Create a new subdirectory for the FPU support code in arch/x86/kernel/fpu/.
Rename 'i387.c' to 'core.c' - as this really collects the core FPU support
code, nothing i387 specific.
We'll better organize this directory in later patches.
Reviewed-by: Borislav Petkov <bp@alien8.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
obj-y += resource.o
obj-y += process.o
-obj-y += i387.o xsave.o
+obj-y += fpu/
obj-y += ptrace.o
obj-$(CONFIG_X86_32) += tls.o
obj-$(CONFIG_IA32_EMULATION) += tls.o
--- /dev/null
+#
+# Build rules for the FPU support code:
+#
+
+obj-y += core.o xsave.o
--- /dev/null
+/*
+ * Copyright (C) 1994 Linus Torvalds
+ *
+ * Pentium III FXSR, SSE support
+ * General FPU state handling cleanups
+ * Gareth Hughes <gareth@valinux.com>, May 2000
+ */
+#include <linux/module.h>
+#include <linux/regset.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+
+#include <asm/sigcontext.h>
+#include <asm/processor.h>
+#include <asm/math_emu.h>
+#include <asm/tlbflush.h>
+#include <asm/uaccess.h>
+#include <asm/ptrace.h>
+#include <asm/i387.h>
+#include <asm/fpu-internal.h>
+#include <asm/user.h>
+
+static DEFINE_PER_CPU(bool, in_kernel_fpu);
+
+void kernel_fpu_disable(void)
+{
+ WARN_ON(this_cpu_read(in_kernel_fpu));
+ this_cpu_write(in_kernel_fpu, true);
+}
+
+void kernel_fpu_enable(void)
+{
+ this_cpu_write(in_kernel_fpu, false);
+}
+
+/*
+ * Were we in an interrupt that interrupted kernel mode?
+ *
+ * On others, we can do a kernel_fpu_begin/end() pair *ONLY* if that
+ * pair does nothing at all: the thread must not have fpu (so
+ * that we don't try to save the FPU state), and TS must
+ * be set (so that the clts/stts pair does nothing that is
+ * visible in the interrupted kernel thread).
+ *
+ * Except for the eagerfpu case when we return true; in the likely case
+ * the thread has FPU but we are not going to set/clear TS.
+ */
+static inline bool interrupted_kernel_fpu_idle(void)
+{
+ if (this_cpu_read(in_kernel_fpu))
+ return false;
+
+ if (use_eager_fpu())
+ return true;
+
+ return !__thread_has_fpu(current) &&
+ (read_cr0() & X86_CR0_TS);
+}
+
+/*
+ * Were we in user mode (or vm86 mode) when we were
+ * interrupted?
+ *
+ * Doing kernel_fpu_begin/end() is ok if we are running
+ * in an interrupt context from user mode - we'll just
+ * save the FPU state as required.
+ */
+static inline bool interrupted_user_mode(void)
+{
+ struct pt_regs *regs = get_irq_regs();
+ return regs && user_mode(regs);
+}
+
+/*
+ * Can we use the FPU in kernel mode with the
+ * whole "kernel_fpu_begin/end()" sequence?
+ *
+ * It's always ok in process context (ie "not interrupt")
+ * but it is sometimes ok even from an irq.
+ */
+bool irq_fpu_usable(void)
+{
+ return !in_interrupt() ||
+ interrupted_user_mode() ||
+ interrupted_kernel_fpu_idle();
+}
+EXPORT_SYMBOL(irq_fpu_usable);
+
+void __kernel_fpu_begin(void)
+{
+ struct task_struct *me = current;
+
+ this_cpu_write(in_kernel_fpu, true);
+
+ if (__thread_has_fpu(me)) {
+ __save_init_fpu(me);
+ } else {
+ this_cpu_write(fpu_owner_task, NULL);
+ if (!use_eager_fpu())
+ clts();
+ }
+}
+EXPORT_SYMBOL(__kernel_fpu_begin);
+
+void __kernel_fpu_end(void)
+{
+ struct task_struct *me = current;
+
+ if (__thread_has_fpu(me)) {
+ if (WARN_ON(restore_fpu_checking(me)))
+ fpu_reset_state(me);
+ } else if (!use_eager_fpu()) {
+ stts();
+ }
+
+ this_cpu_write(in_kernel_fpu, false);
+}
+EXPORT_SYMBOL(__kernel_fpu_end);
+
+/*
+ * Save the FPU state (initialize it if necessary):
+ *
+ * This only ever gets called for the current task.
+ */
+void fpu__save(struct task_struct *tsk)
+{
+ WARN_ON(tsk != current);
+
+ preempt_disable();
+ if (__thread_has_fpu(tsk)) {
+ if (use_eager_fpu()) {
+ __save_fpu(tsk);
+ } else {
+ __save_init_fpu(tsk);
+ __thread_fpu_end(tsk);
+ }
+ }
+ preempt_enable();
+}
+EXPORT_SYMBOL_GPL(fpu__save);
+
+unsigned int mxcsr_feature_mask __read_mostly = 0xffffffffu;
+unsigned int xstate_size;
+EXPORT_SYMBOL_GPL(xstate_size);
+static struct i387_fxsave_struct fx_scratch;
+
+static void mxcsr_feature_mask_init(void)
+{
+ unsigned long mask = 0;
+
+ if (cpu_has_fxsr) {
+ memset(&fx_scratch, 0, sizeof(struct i387_fxsave_struct));
+ asm volatile("fxsave %0" : "+m" (fx_scratch));
+ mask = fx_scratch.mxcsr_mask;
+ if (mask == 0)
+ mask = 0x0000ffbf;
+ }
+ mxcsr_feature_mask &= mask;
+}
+
+static void fpstate_xstate_init_size(void)
+{
+ /*
+ * Note that xstate_size might be overwriten later during
+ * xsave_init().
+ */
+
+ if (!cpu_has_fpu) {
+ /*
+ * Disable xsave as we do not support it if i387
+ * emulation is enabled.
+ */
+ setup_clear_cpu_cap(X86_FEATURE_XSAVE);
+ setup_clear_cpu_cap(X86_FEATURE_XSAVEOPT);
+ xstate_size = sizeof(struct i387_soft_struct);
+ return;
+ }
+
+ if (cpu_has_fxsr)
+ xstate_size = sizeof(struct i387_fxsave_struct);
+ else
+ xstate_size = sizeof(struct i387_fsave_struct);
+}
+
+/*
+ * Called on the boot CPU at bootup to set up the initial FPU state that
+ * is later cloned into all processes.
+ *
+ * Also called on secondary CPUs to set up the FPU state of their
+ * idle threads.
+ */
+void fpu__cpu_init(void)
+{
+ unsigned long cr0;
+ unsigned long cr4_mask = 0;
+
+#ifndef CONFIG_MATH_EMULATION
+ if (!cpu_has_fpu) {
+ pr_emerg("No FPU found and no math emulation present\n");
+ pr_emerg("Giving up\n");
+ for (;;)
+ asm volatile("hlt");
+ }
+#endif
+ if (cpu_has_fxsr)
+ cr4_mask |= X86_CR4_OSFXSR;
+ if (cpu_has_xmm)
+ cr4_mask |= X86_CR4_OSXMMEXCPT;
+ if (cr4_mask)
+ cr4_set_bits(cr4_mask);
+
+ cr0 = read_cr0();
+ cr0 &= ~(X86_CR0_TS|X86_CR0_EM); /* clear TS and EM */
+ if (!cpu_has_fpu)
+ cr0 |= X86_CR0_EM;
+ write_cr0(cr0);
+
+ /*
+ * fpstate_xstate_init_size() is only called once, to avoid overriding
+ * 'xstate_size' during (secondary CPU) bootup or during CPU hotplug.
+ */
+ if (xstate_size == 0)
+ fpstate_xstate_init_size();
+
+ mxcsr_feature_mask_init();
+ xsave_init();
+ eager_fpu_init();
+}
+
+void fpstate_init(struct fpu *fpu)
+{
+ if (!cpu_has_fpu) {
+ finit_soft_fpu(&fpu->state->soft);
+ return;
+ }
+
+ memset(fpu->state, 0, xstate_size);
+
+ if (cpu_has_fxsr) {
+ fx_finit(&fpu->state->fxsave);
+ } else {
+ struct i387_fsave_struct *fp = &fpu->state->fsave;
+ fp->cwd = 0xffff037fu;
+ fp->swd = 0xffff0000u;
+ fp->twd = 0xffffffffu;
+ fp->fos = 0xffff0000u;
+ }
+}
+EXPORT_SYMBOL_GPL(fpstate_init);
+
+int fpstate_alloc(struct fpu *fpu)
+{
+ if (fpu->state)
+ return 0;
+
+ fpu->state = kmem_cache_alloc(task_xstate_cachep, GFP_KERNEL);
+ if (!fpu->state)
+ return -ENOMEM;
+
+ /* The CPU requires the FPU state to be aligned to 16 byte boundaries: */
+ WARN_ON((unsigned long)fpu->state & 15);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(fpstate_alloc);
+
+/*
+ * Allocate the backing store for the current task's FPU registers
+ * and initialize the registers themselves as well.
+ *
+ * Can fail.
+ */
+int fpstate_alloc_init(struct task_struct *curr)
+{
+ int ret;
+
+ if (WARN_ON_ONCE(curr != current))
+ return -EINVAL;
+ if (WARN_ON_ONCE(curr->flags & PF_USED_MATH))
+ return -EINVAL;
+
+ /*
+ * Memory allocation at the first usage of the FPU and other state.
+ */
+ ret = fpstate_alloc(&curr->thread.fpu);
+ if (ret)
+ return ret;
+
+ fpstate_init(&curr->thread.fpu);
+
+ /* Safe to do for the current task: */
+ curr->flags |= PF_USED_MATH;
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(fpstate_alloc_init);
+
+/*
+ * The _current_ task is using the FPU for the first time
+ * so initialize it and set the mxcsr to its default
+ * value at reset if we support XMM instructions and then
+ * remember the current task has used the FPU.
+ */
+static int fpu__unlazy_stopped(struct task_struct *child)
+{
+ int ret;
+
+ if (WARN_ON_ONCE(child == current))
+ return -EINVAL;
+
+ if (child->flags & PF_USED_MATH) {
+ task_disable_lazy_fpu_restore(child);
+ return 0;
+ }
+
+ /*
+ * Memory allocation at the first usage of the FPU and other state.
+ */
+ ret = fpstate_alloc(&child->thread.fpu);
+ if (ret)
+ return ret;
+
+ fpstate_init(&child->thread.fpu);
+
+ /* Safe to do for stopped child tasks: */
+ child->flags |= PF_USED_MATH;
+
+ return 0;
+}
+
+/*
+ * The xstateregs_active() routine is the same as the fpregs_active() routine,
+ * as the "regset->n" for the xstate regset will be updated based on the feature
+ * capabilites supported by the xsave.
+ */
+int fpregs_active(struct task_struct *target, const struct user_regset *regset)
+{
+ return tsk_used_math(target) ? regset->n : 0;
+}
+
+int xfpregs_active(struct task_struct *target, const struct user_regset *regset)
+{
+ return (cpu_has_fxsr && tsk_used_math(target)) ? regset->n : 0;
+}
+
+int xfpregs_get(struct task_struct *target, const struct user_regset *regset,
+ unsigned int pos, unsigned int count,
+ void *kbuf, void __user *ubuf)
+{
+ int ret;
+
+ if (!cpu_has_fxsr)
+ return -ENODEV;
+
+ ret = fpu__unlazy_stopped(target);
+ if (ret)
+ return ret;
+
+ sanitize_i387_state(target);
+
+ return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
+ &target->thread.fpu.state->fxsave, 0, -1);
+}
+
+int xfpregs_set(struct task_struct *target, const struct user_regset *regset,
+ unsigned int pos, unsigned int count,
+ const void *kbuf, const void __user *ubuf)
+{
+ int ret;
+
+ if (!cpu_has_fxsr)
+ return -ENODEV;
+
+ ret = fpu__unlazy_stopped(target);
+ if (ret)
+ return ret;
+
+ sanitize_i387_state(target);
+
+ ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
+ &target->thread.fpu.state->fxsave, 0, -1);
+
+ /*
+ * mxcsr reserved bits must be masked to zero for security reasons.
+ */
+ target->thread.fpu.state->fxsave.mxcsr &= mxcsr_feature_mask;
+
+ /*
+ * update the header bits in the xsave header, indicating the
+ * presence of FP and SSE state.
+ */
+ if (cpu_has_xsave)
+ target->thread.fpu.state->xsave.xsave_hdr.xstate_bv |= XSTATE_FPSSE;
+
+ return ret;
+}
+
+int xstateregs_get(struct task_struct *target, const struct user_regset *regset,
+ unsigned int pos, unsigned int count,
+ void *kbuf, void __user *ubuf)
+{
+ struct xsave_struct *xsave;
+ int ret;
+
+ if (!cpu_has_xsave)
+ return -ENODEV;
+
+ ret = fpu__unlazy_stopped(target);
+ if (ret)
+ return ret;
+
+ xsave = &target->thread.fpu.state->xsave;
+
+ /*
+ * Copy the 48bytes defined by the software first into the xstate
+ * memory layout in the thread struct, so that we can copy the entire
+ * xstateregs to the user using one user_regset_copyout().
+ */
+ memcpy(&xsave->i387.sw_reserved,
+ xstate_fx_sw_bytes, sizeof(xstate_fx_sw_bytes));
+ /*
+ * Copy the xstate memory layout.
+ */
+ ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, xsave, 0, -1);
+ return ret;
+}
+
+int xstateregs_set(struct task_struct *target, const struct user_regset *regset,
+ unsigned int pos, unsigned int count,
+ const void *kbuf, const void __user *ubuf)
+{
+ struct xsave_struct *xsave;
+ int ret;
+
+ if (!cpu_has_xsave)
+ return -ENODEV;
+
+ ret = fpu__unlazy_stopped(target);
+ if (ret)
+ return ret;
+
+ xsave = &target->thread.fpu.state->xsave;
+
+ ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, xsave, 0, -1);
+ /*
+ * mxcsr reserved bits must be masked to zero for security reasons.
+ */
+ xsave->i387.mxcsr &= mxcsr_feature_mask;
+ xsave->xsave_hdr.xstate_bv &= pcntxt_mask;
+ /*
+ * These bits must be zero.
+ */
+ memset(&xsave->xsave_hdr.reserved, 0, 48);
+ return ret;
+}
+
+#if defined CONFIG_X86_32 || defined CONFIG_IA32_EMULATION
+
+/*
+ * FPU tag word conversions.
+ */
+
+static inline unsigned short twd_i387_to_fxsr(unsigned short twd)
+{
+ unsigned int tmp; /* to avoid 16 bit prefixes in the code */
+
+ /* Transform each pair of bits into 01 (valid) or 00 (empty) */
+ tmp = ~twd;
+ tmp = (tmp | (tmp>>1)) & 0x5555; /* 0V0V0V0V0V0V0V0V */
+ /* and move the valid bits to the lower byte. */
+ tmp = (tmp | (tmp >> 1)) & 0x3333; /* 00VV00VV00VV00VV */
+ tmp = (tmp | (tmp >> 2)) & 0x0f0f; /* 0000VVVV0000VVVV */
+ tmp = (tmp | (tmp >> 4)) & 0x00ff; /* 00000000VVVVVVVV */
+
+ return tmp;
+}
+
+#define FPREG_ADDR(f, n) ((void *)&(f)->st_space + (n) * 16)
+#define FP_EXP_TAG_VALID 0
+#define FP_EXP_TAG_ZERO 1
+#define FP_EXP_TAG_SPECIAL 2
+#define FP_EXP_TAG_EMPTY 3
+
+static inline u32 twd_fxsr_to_i387(struct i387_fxsave_struct *fxsave)
+{
+ struct _fpxreg *st;
+ u32 tos = (fxsave->swd >> 11) & 7;
+ u32 twd = (unsigned long) fxsave->twd;
+ u32 tag;
+ u32 ret = 0xffff0000u;
+ int i;
+
+ for (i = 0; i < 8; i++, twd >>= 1) {
+ if (twd & 0x1) {
+ st = FPREG_ADDR(fxsave, (i - tos) & 7);
+
+ switch (st->exponent & 0x7fff) {
+ case 0x7fff:
+ tag = FP_EXP_TAG_SPECIAL;
+ break;
+ case 0x0000:
+ if (!st->significand[0] &&
+ !st->significand[1] &&
+ !st->significand[2] &&
+ !st->significand[3])
+ tag = FP_EXP_TAG_ZERO;
+ else
+ tag = FP_EXP_TAG_SPECIAL;
+ break;
+ default:
+ if (st->significand[3] & 0x8000)
+ tag = FP_EXP_TAG_VALID;
+ else
+ tag = FP_EXP_TAG_SPECIAL;
+ break;
+ }
+ } else {
+ tag = FP_EXP_TAG_EMPTY;
+ }
+ ret |= tag << (2 * i);
+ }
+ return ret;
+}
+
+/*
+ * FXSR floating point environment conversions.
+ */
+
+void
+convert_from_fxsr(struct user_i387_ia32_struct *env, struct task_struct *tsk)
+{
+ struct i387_fxsave_struct *fxsave = &tsk->thread.fpu.state->fxsave;
+ struct _fpreg *to = (struct _fpreg *) &env->st_space[0];
+ struct _fpxreg *from = (struct _fpxreg *) &fxsave->st_space[0];
+ int i;
+
+ env->cwd = fxsave->cwd | 0xffff0000u;
+ env->swd = fxsave->swd | 0xffff0000u;
+ env->twd = twd_fxsr_to_i387(fxsave);
+
+#ifdef CONFIG_X86_64
+ env->fip = fxsave->rip;
+ env->foo = fxsave->rdp;
+ /*
+ * should be actually ds/cs at fpu exception time, but
+ * that information is not available in 64bit mode.
+ */
+ env->fcs = task_pt_regs(tsk)->cs;
+ if (tsk == current) {
+ savesegment(ds, env->fos);
+ } else {
+ env->fos = tsk->thread.ds;
+ }
+ env->fos |= 0xffff0000;
+#else
+ env->fip = fxsave->fip;
+ env->fcs = (u16) fxsave->fcs | ((u32) fxsave->fop << 16);
+ env->foo = fxsave->foo;
+ env->fos = fxsave->fos;
+#endif
+
+ for (i = 0; i < 8; ++i)
+ memcpy(&to[i], &from[i], sizeof(to[0]));
+}
+
+void convert_to_fxsr(struct task_struct *tsk,
+ const struct user_i387_ia32_struct *env)
+
+{
+ struct i387_fxsave_struct *fxsave = &tsk->thread.fpu.state->fxsave;
+ struct _fpreg *from = (struct _fpreg *) &env->st_space[0];
+ struct _fpxreg *to = (struct _fpxreg *) &fxsave->st_space[0];
+ int i;
+
+ fxsave->cwd = env->cwd;
+ fxsave->swd = env->swd;
+ fxsave->twd = twd_i387_to_fxsr(env->twd);
+ fxsave->fop = (u16) ((u32) env->fcs >> 16);
+#ifdef CONFIG_X86_64
+ fxsave->rip = env->fip;
+ fxsave->rdp = env->foo;
+ /* cs and ds ignored */
+#else
+ fxsave->fip = env->fip;
+ fxsave->fcs = (env->fcs & 0xffff);
+ fxsave->foo = env->foo;
+ fxsave->fos = env->fos;
+#endif
+
+ for (i = 0; i < 8; ++i)
+ memcpy(&to[i], &from[i], sizeof(from[0]));
+}
+
+int fpregs_get(struct task_struct *target, const struct user_regset *regset,
+ unsigned int pos, unsigned int count,
+ void *kbuf, void __user *ubuf)
+{
+ struct user_i387_ia32_struct env;
+ int ret;
+
+ ret = fpu__unlazy_stopped(target);
+ if (ret)
+ return ret;
+
+ if (!static_cpu_has(X86_FEATURE_FPU))
+ return fpregs_soft_get(target, regset, pos, count, kbuf, ubuf);
+
+ if (!cpu_has_fxsr)
+ return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
+ &target->thread.fpu.state->fsave, 0,
+ -1);
+
+ sanitize_i387_state(target);
+
+ if (kbuf && pos == 0 && count == sizeof(env)) {
+ convert_from_fxsr(kbuf, target);
+ return 0;
+ }
+
+ convert_from_fxsr(&env, target);
+
+ return user_regset_copyout(&pos, &count, &kbuf, &ubuf, &env, 0, -1);
+}
+
+int fpregs_set(struct task_struct *target, const struct user_regset *regset,
+ unsigned int pos, unsigned int count,
+ const void *kbuf, const void __user *ubuf)
+{
+ struct user_i387_ia32_struct env;
+ int ret;
+
+ ret = fpu__unlazy_stopped(target);
+ if (ret)
+ return ret;
+
+ sanitize_i387_state(target);
+
+ if (!static_cpu_has(X86_FEATURE_FPU))
+ return fpregs_soft_set(target, regset, pos, count, kbuf, ubuf);
+
+ if (!cpu_has_fxsr)
+ return user_regset_copyin(&pos, &count, &kbuf, &ubuf,
+ &target->thread.fpu.state->fsave, 0,
+ -1);
+
+ if (pos > 0 || count < sizeof(env))
+ convert_from_fxsr(&env, target);
+
+ ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &env, 0, -1);
+ if (!ret)
+ convert_to_fxsr(target, &env);
+
+ /*
+ * update the header bit in the xsave header, indicating the
+ * presence of FP.
+ */
+ if (cpu_has_xsave)
+ target->thread.fpu.state->xsave.xsave_hdr.xstate_bv |= XSTATE_FP;
+ return ret;
+}
+
+/*
+ * FPU state for core dumps.
+ * This is only used for a.out dumps now.
+ * It is declared generically using elf_fpregset_t (which is
+ * struct user_i387_struct) but is in fact only used for 32-bit
+ * dumps, so on 64-bit it is really struct user_i387_ia32_struct.
+ */
+int dump_fpu(struct pt_regs *regs, struct user_i387_struct *fpu)
+{
+ struct task_struct *tsk = current;
+ int fpvalid;
+
+ fpvalid = !!used_math();
+ if (fpvalid)
+ fpvalid = !fpregs_get(tsk, NULL,
+ 0, sizeof(struct user_i387_ia32_struct),
+ fpu, NULL);
+
+ return fpvalid;
+}
+EXPORT_SYMBOL(dump_fpu);
+
+#endif /* CONFIG_X86_32 || CONFIG_IA32_EMULATION */
+
+static int __init no_387(char *s)
+{
+ setup_clear_cpu_cap(X86_FEATURE_FPU);
+ return 1;
+}
+
+__setup("no387", no_387);
+
+/*
+ * Set the X86_FEATURE_FPU CPU-capability bit based on
+ * trying to execute an actual sequence of FPU instructions:
+ */
+void fpu__detect(struct cpuinfo_x86 *c)
+{
+ unsigned long cr0;
+ u16 fsw, fcw;
+
+ fsw = fcw = 0xffff;
+
+ cr0 = read_cr0();
+ cr0 &= ~(X86_CR0_TS | X86_CR0_EM);
+ write_cr0(cr0);
+
+ asm volatile("fninit ; fnstsw %0 ; fnstcw %1"
+ : "+m" (fsw), "+m" (fcw));
+
+ if (fsw == 0 && (fcw & 0x103f) == 0x003f)
+ set_cpu_cap(c, X86_FEATURE_FPU);
+ else
+ clear_cpu_cap(c, X86_FEATURE_FPU);
+
+ /* The final cr0 value is set in fpu_init() */
+}
--- /dev/null
+/*
+ * xsave/xrstor support.
+ *
+ * Author: Suresh Siddha <suresh.b.siddha@intel.com>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/bootmem.h>
+#include <linux/compat.h>
+#include <linux/cpu.h>
+#include <asm/i387.h>
+#include <asm/fpu-internal.h>
+#include <asm/sigframe.h>
+#include <asm/tlbflush.h>
+#include <asm/xcr.h>
+
+/*
+ * Supported feature mask by the CPU and the kernel.
+ */
+u64 pcntxt_mask;
+
+/*
+ * Represents init state for the supported extended state.
+ */
+struct xsave_struct *init_xstate_buf;
+
+static struct _fpx_sw_bytes fx_sw_reserved, fx_sw_reserved_ia32;
+static unsigned int *xstate_offsets, *xstate_sizes;
+static unsigned int xstate_comp_offsets[sizeof(pcntxt_mask)*8];
+static unsigned int xstate_features;
+
+/*
+ * If a processor implementation discern that a processor state component is
+ * in its initialized state it may modify the corresponding bit in the
+ * xsave_hdr.xstate_bv as '0', with out modifying the corresponding memory
+ * layout in the case of xsaveopt. While presenting the xstate information to
+ * the user, we always ensure that the memory layout of a feature will be in
+ * the init state if the corresponding header bit is zero. This is to ensure
+ * that the user doesn't see some stale state in the memory layout during
+ * signal handling, debugging etc.
+ */
+void __sanitize_i387_state(struct task_struct *tsk)
+{
+ struct i387_fxsave_struct *fx = &tsk->thread.fpu.state->fxsave;
+ int feature_bit = 0x2;
+ u64 xstate_bv;
+
+ if (!fx)
+ return;
+
+ xstate_bv = tsk->thread.fpu.state->xsave.xsave_hdr.xstate_bv;
+
+ /*
+ * None of the feature bits are in init state. So nothing else
+ * to do for us, as the memory layout is up to date.
+ */
+ if ((xstate_bv & pcntxt_mask) == pcntxt_mask)
+ return;
+
+ /*
+ * FP is in init state
+ */
+ if (!(xstate_bv & XSTATE_FP)) {
+ fx->cwd = 0x37f;
+ fx->swd = 0;
+ fx->twd = 0;
+ fx->fop = 0;
+ fx->rip = 0;
+ fx->rdp = 0;
+ memset(&fx->st_space[0], 0, 128);
+ }
+
+ /*
+ * SSE is in init state
+ */
+ if (!(xstate_bv & XSTATE_SSE))
+ memset(&fx->xmm_space[0], 0, 256);
+
+ xstate_bv = (pcntxt_mask & ~xstate_bv) >> 2;
+
+ /*
+ * Update all the other memory layouts for which the corresponding
+ * header bit is in the init state.
+ */
+ while (xstate_bv) {
+ if (xstate_bv & 0x1) {
+ int offset = xstate_offsets[feature_bit];
+ int size = xstate_sizes[feature_bit];
+
+ memcpy(((void *) fx) + offset,
+ ((void *) init_xstate_buf) + offset,
+ size);
+ }
+
+ xstate_bv >>= 1;
+ feature_bit++;
+ }
+}
+
+/*
+ * Check for the presence of extended state information in the
+ * user fpstate pointer in the sigcontext.
+ */
+static inline int check_for_xstate(struct i387_fxsave_struct __user *buf,
+ void __user *fpstate,
+ struct _fpx_sw_bytes *fx_sw)
+{
+ int min_xstate_size = sizeof(struct i387_fxsave_struct) +
+ sizeof(struct xsave_hdr_struct);
+ unsigned int magic2;
+
+ if (__copy_from_user(fx_sw, &buf->sw_reserved[0], sizeof(*fx_sw)))
+ return -1;
+
+ /* Check for the first magic field and other error scenarios. */
+ if (fx_sw->magic1 != FP_XSTATE_MAGIC1 ||
+ fx_sw->xstate_size < min_xstate_size ||
+ fx_sw->xstate_size > xstate_size ||
+ fx_sw->xstate_size > fx_sw->extended_size)
+ return -1;
+
+ /*
+ * Check for the presence of second magic word at the end of memory
+ * layout. This detects the case where the user just copied the legacy
+ * fpstate layout with out copying the extended state information
+ * in the memory layout.
+ */
+ if (__get_user(magic2, (__u32 __user *)(fpstate + fx_sw->xstate_size))
+ || magic2 != FP_XSTATE_MAGIC2)
+ return -1;
+
+ return 0;
+}
+
+/*
+ * Signal frame handlers.
+ */
+static inline int save_fsave_header(struct task_struct *tsk, void __user *buf)
+{
+ if (use_fxsr()) {
+ struct xsave_struct *xsave = &tsk->thread.fpu.state->xsave;
+ struct user_i387_ia32_struct env;
+ struct _fpstate_ia32 __user *fp = buf;
+
+ convert_from_fxsr(&env, tsk);
+
+ if (__copy_to_user(buf, &env, sizeof(env)) ||
+ __put_user(xsave->i387.swd, &fp->status) ||
+ __put_user(X86_FXSR_MAGIC, &fp->magic))
+ return -1;
+ } else {
+ struct i387_fsave_struct __user *fp = buf;
+ u32 swd;
+ if (__get_user(swd, &fp->swd) || __put_user(swd, &fp->status))
+ return -1;
+ }
+
+ return 0;
+}
+
+static inline int save_xstate_epilog(void __user *buf, int ia32_frame)
+{
+ struct xsave_struct __user *x = buf;
+ struct _fpx_sw_bytes *sw_bytes;
+ u32 xstate_bv;
+ int err;
+
+ /* Setup the bytes not touched by the [f]xsave and reserved for SW. */
+ sw_bytes = ia32_frame ? &fx_sw_reserved_ia32 : &fx_sw_reserved;
+ err = __copy_to_user(&x->i387.sw_reserved, sw_bytes, sizeof(*sw_bytes));
+
+ if (!use_xsave())
+ return err;
+
+ err |= __put_user(FP_XSTATE_MAGIC2, (__u32 *)(buf + xstate_size));
+
+ /*
+ * Read the xstate_bv which we copied (directly from the cpu or
+ * from the state in task struct) to the user buffers.
+ */
+ err |= __get_user(xstate_bv, (__u32 *)&x->xsave_hdr.xstate_bv);
+
+ /*
+ * For legacy compatible, we always set FP/SSE bits in the bit
+ * vector while saving the state to the user context. This will
+ * enable us capturing any changes(during sigreturn) to
+ * the FP/SSE bits by the legacy applications which don't touch
+ * xstate_bv in the xsave header.
+ *
+ * xsave aware apps can change the xstate_bv in the xsave
+ * header as well as change any contents in the memory layout.
+ * xrestore as part of sigreturn will capture all the changes.
+ */
+ xstate_bv |= XSTATE_FPSSE;
+
+ err |= __put_user(xstate_bv, (__u32 *)&x->xsave_hdr.xstate_bv);
+
+ return err;
+}
+
+static inline int save_user_xstate(struct xsave_struct __user *buf)
+{
+ int err;
+
+ if (use_xsave())
+ err = xsave_user(buf);
+ else if (use_fxsr())
+ err = fxsave_user((struct i387_fxsave_struct __user *) buf);
+ else
+ err = fsave_user((struct i387_fsave_struct __user *) buf);
+
+ if (unlikely(err) && __clear_user(buf, xstate_size))
+ err = -EFAULT;
+ return err;
+}
+
+/*
+ * Save the fpu, extended register state to the user signal frame.
+ *
+ * 'buf_fx' is the 64-byte aligned pointer at which the [f|fx|x]save
+ * state is copied.
+ * 'buf' points to the 'buf_fx' or to the fsave header followed by 'buf_fx'.
+ *
+ * buf == buf_fx for 64-bit frames and 32-bit fsave frame.
+ * buf != buf_fx for 32-bit frames with fxstate.
+ *
+ * If the fpu, extended register state is live, save the state directly
+ * to the user frame pointed by the aligned pointer 'buf_fx'. Otherwise,
+ * copy the thread's fpu state to the user frame starting at 'buf_fx'.
+ *
+ * If this is a 32-bit frame with fxstate, put a fsave header before
+ * the aligned state at 'buf_fx'.
+ *
+ * For [f]xsave state, update the SW reserved fields in the [f]xsave frame
+ * indicating the absence/presence of the extended state to the user.
+ */
+int save_xstate_sig(void __user *buf, void __user *buf_fx, int size)
+{
+ struct xsave_struct *xsave = ¤t->thread.fpu.state->xsave;
+ struct task_struct *tsk = current;
+ int ia32_fxstate = (buf != buf_fx);
+
+ ia32_fxstate &= (config_enabled(CONFIG_X86_32) ||
+ config_enabled(CONFIG_IA32_EMULATION));
+
+ if (!access_ok(VERIFY_WRITE, buf, size))
+ return -EACCES;
+
+ if (!static_cpu_has(X86_FEATURE_FPU))
+ return fpregs_soft_get(current, NULL, 0,
+ sizeof(struct user_i387_ia32_struct), NULL,
+ (struct _fpstate_ia32 __user *) buf) ? -1 : 1;
+
+ if (user_has_fpu()) {
+ /* Save the live register state to the user directly. */
+ if (save_user_xstate(buf_fx))
+ return -1;
+ /* Update the thread's fxstate to save the fsave header. */
+ if (ia32_fxstate)
+ fpu_fxsave(&tsk->thread.fpu);
+ } else {
+ sanitize_i387_state(tsk);
+ if (__copy_to_user(buf_fx, xsave, xstate_size))
+ return -1;
+ }
+
+ /* Save the fsave header for the 32-bit frames. */
+ if ((ia32_fxstate || !use_fxsr()) && save_fsave_header(tsk, buf))
+ return -1;
+
+ if (use_fxsr() && save_xstate_epilog(buf_fx, ia32_fxstate))
+ return -1;
+
+ return 0;
+}
+
+static inline void
+sanitize_restored_xstate(struct task_struct *tsk,
+ struct user_i387_ia32_struct *ia32_env,
+ u64 xstate_bv, int fx_only)
+{
+ struct xsave_struct *xsave = &tsk->thread.fpu.state->xsave;
+ struct xsave_hdr_struct *xsave_hdr = &xsave->xsave_hdr;
+
+ if (use_xsave()) {
+ /* These bits must be zero. */
+ memset(xsave_hdr->reserved, 0, 48);
+
+ /*
+ * Init the state that is not present in the memory
+ * layout and not enabled by the OS.
+ */
+ if (fx_only)
+ xsave_hdr->xstate_bv = XSTATE_FPSSE;
+ else
+ xsave_hdr->xstate_bv &= (pcntxt_mask & xstate_bv);
+ }
+
+ if (use_fxsr()) {
+ /*
+ * mscsr reserved bits must be masked to zero for security
+ * reasons.
+ */
+ xsave->i387.mxcsr &= mxcsr_feature_mask;
+
+ convert_to_fxsr(tsk, ia32_env);
+ }
+}
+
+/*
+ * Restore the extended state if present. Otherwise, restore the FP/SSE state.
+ */
+static inline int restore_user_xstate(void __user *buf, u64 xbv, int fx_only)
+{
+ if (use_xsave()) {
+ if ((unsigned long)buf % 64 || fx_only) {
+ u64 init_bv = pcntxt_mask & ~XSTATE_FPSSE;
+ xrstor_state(init_xstate_buf, init_bv);
+ return fxrstor_user(buf);
+ } else {
+ u64 init_bv = pcntxt_mask & ~xbv;
+ if (unlikely(init_bv))
+ xrstor_state(init_xstate_buf, init_bv);
+ return xrestore_user(buf, xbv);
+ }
+ } else if (use_fxsr()) {
+ return fxrstor_user(buf);
+ } else
+ return frstor_user(buf);
+}
+
+int __restore_xstate_sig(void __user *buf, void __user *buf_fx, int size)
+{
+ int ia32_fxstate = (buf != buf_fx);
+ struct task_struct *tsk = current;
+ int state_size = xstate_size;
+ u64 xstate_bv = 0;
+ int fx_only = 0;
+
+ ia32_fxstate &= (config_enabled(CONFIG_X86_32) ||
+ config_enabled(CONFIG_IA32_EMULATION));
+
+ if (!buf) {
+ fpu_reset_state(tsk);
+ return 0;
+ }
+
+ if (!access_ok(VERIFY_READ, buf, size))
+ return -EACCES;
+
+ if (!used_math() && fpstate_alloc_init(tsk))
+ return -1;
+
+ if (!static_cpu_has(X86_FEATURE_FPU))
+ return fpregs_soft_set(current, NULL,
+ 0, sizeof(struct user_i387_ia32_struct),
+ NULL, buf) != 0;
+
+ if (use_xsave()) {
+ struct _fpx_sw_bytes fx_sw_user;
+ if (unlikely(check_for_xstate(buf_fx, buf_fx, &fx_sw_user))) {
+ /*
+ * Couldn't find the extended state information in the
+ * memory layout. Restore just the FP/SSE and init all
+ * the other extended state.
+ */
+ state_size = sizeof(struct i387_fxsave_struct);
+ fx_only = 1;
+ } else {
+ state_size = fx_sw_user.xstate_size;
+ xstate_bv = fx_sw_user.xstate_bv;
+ }
+ }
+
+ if (ia32_fxstate) {
+ /*
+ * For 32-bit frames with fxstate, copy the user state to the
+ * thread's fpu state, reconstruct fxstate from the fsave
+ * header. Sanitize the copied state etc.
+ */
+ struct fpu *fpu = &tsk->thread.fpu;
+ struct user_i387_ia32_struct env;
+ int err = 0;
+
+ /*
+ * Drop the current fpu which clears used_math(). This ensures
+ * that any context-switch during the copy of the new state,
+ * avoids the intermediate state from getting restored/saved.
+ * Thus avoiding the new restored state from getting corrupted.
+ * We will be ready to restore/save the state only after
+ * set_used_math() is again set.
+ */
+ drop_fpu(tsk);
+
+ if (__copy_from_user(&fpu->state->xsave, buf_fx, state_size) ||
+ __copy_from_user(&env, buf, sizeof(env))) {
+ fpstate_init(fpu);
+ err = -1;
+ } else {
+ sanitize_restored_xstate(tsk, &env, xstate_bv, fx_only);
+ }
+
+ set_used_math();
+ if (use_eager_fpu()) {
+ preempt_disable();
+ math_state_restore();
+ preempt_enable();
+ }
+
+ return err;
+ } else {
+ /*
+ * For 64-bit frames and 32-bit fsave frames, restore the user
+ * state to the registers directly (with exceptions handled).
+ */
+ user_fpu_begin();
+ if (restore_user_xstate(buf_fx, xstate_bv, fx_only)) {
+ fpu_reset_state(tsk);
+ return -1;
+ }
+ }
+
+ return 0;
+}
+
+/*
+ * Prepare the SW reserved portion of the fxsave memory layout, indicating
+ * the presence of the extended state information in the memory layout
+ * pointed by the fpstate pointer in the sigcontext.
+ * This will be saved when ever the FP and extended state context is
+ * saved on the user stack during the signal handler delivery to the user.
+ */
+static void prepare_fx_sw_frame(void)
+{
+ int fsave_header_size = sizeof(struct i387_fsave_struct);
+ int size = xstate_size + FP_XSTATE_MAGIC2_SIZE;
+
+ if (config_enabled(CONFIG_X86_32))
+ size += fsave_header_size;
+
+ fx_sw_reserved.magic1 = FP_XSTATE_MAGIC1;
+ fx_sw_reserved.extended_size = size;
+ fx_sw_reserved.xstate_bv = pcntxt_mask;
+ fx_sw_reserved.xstate_size = xstate_size;
+
+ if (config_enabled(CONFIG_IA32_EMULATION)) {
+ fx_sw_reserved_ia32 = fx_sw_reserved;
+ fx_sw_reserved_ia32.extended_size += fsave_header_size;
+ }
+}
+
+/*
+ * Enable the extended processor state save/restore feature
+ */
+static inline void xstate_enable(void)
+{
+ cr4_set_bits(X86_CR4_OSXSAVE);
+ xsetbv(XCR_XFEATURE_ENABLED_MASK, pcntxt_mask);
+}
+
+/*
+ * Record the offsets and sizes of different state managed by the xsave
+ * memory layout.
+ */
+static void __init setup_xstate_features(void)
+{
+ int eax, ebx, ecx, edx, leaf = 0x2;
+
+ xstate_features = fls64(pcntxt_mask);
+ xstate_offsets = alloc_bootmem(xstate_features * sizeof(int));
+ xstate_sizes = alloc_bootmem(xstate_features * sizeof(int));
+
+ do {
+ cpuid_count(XSTATE_CPUID, leaf, &eax, &ebx, &ecx, &edx);
+
+ if (eax == 0)
+ break;
+
+ xstate_offsets[leaf] = ebx;
+ xstate_sizes[leaf] = eax;
+
+ leaf++;
+ } while (1);
+}
+
+/*
+ * This function sets up offsets and sizes of all extended states in
+ * xsave area. This supports both standard format and compacted format
+ * of the xsave aread.
+ *
+ * Input: void
+ * Output: void
+ */
+void setup_xstate_comp(void)
+{
+ unsigned int xstate_comp_sizes[sizeof(pcntxt_mask)*8];
+ int i;
+
+ /*
+ * The FP xstates and SSE xstates are legacy states. They are always
+ * in the fixed offsets in the xsave area in either compacted form
+ * or standard form.
+ */
+ xstate_comp_offsets[0] = 0;
+ xstate_comp_offsets[1] = offsetof(struct i387_fxsave_struct, xmm_space);
+
+ if (!cpu_has_xsaves) {
+ for (i = 2; i < xstate_features; i++) {
+ if (test_bit(i, (unsigned long *)&pcntxt_mask)) {
+ xstate_comp_offsets[i] = xstate_offsets[i];
+ xstate_comp_sizes[i] = xstate_sizes[i];
+ }
+ }
+ return;
+ }
+
+ xstate_comp_offsets[2] = FXSAVE_SIZE + XSAVE_HDR_SIZE;
+
+ for (i = 2; i < xstate_features; i++) {
+ if (test_bit(i, (unsigned long *)&pcntxt_mask))
+ xstate_comp_sizes[i] = xstate_sizes[i];
+ else
+ xstate_comp_sizes[i] = 0;
+
+ if (i > 2)
+ xstate_comp_offsets[i] = xstate_comp_offsets[i-1]
+ + xstate_comp_sizes[i-1];
+
+ }
+}
+
+/*
+ * setup the xstate image representing the init state
+ */
+static void __init setup_init_fpu_buf(void)
+{
+ /*
+ * Setup init_xstate_buf to represent the init state of
+ * all the features managed by the xsave
+ */
+ init_xstate_buf = alloc_bootmem_align(xstate_size,
+ __alignof__(struct xsave_struct));
+ fx_finit(&init_xstate_buf->i387);
+
+ if (!cpu_has_xsave)
+ return;
+
+ setup_xstate_features();
+
+ if (cpu_has_xsaves) {
+ init_xstate_buf->xsave_hdr.xcomp_bv =
+ (u64)1 << 63 | pcntxt_mask;
+ init_xstate_buf->xsave_hdr.xstate_bv = pcntxt_mask;
+ }
+
+ /*
+ * Init all the features state with header_bv being 0x0
+ */
+ xrstor_state_booting(init_xstate_buf, -1);
+ /*
+ * Dump the init state again. This is to identify the init state
+ * of any feature which is not represented by all zero's.
+ */
+ xsave_state_booting(init_xstate_buf, -1);
+}
+
+static enum { AUTO, ENABLE, DISABLE } eagerfpu = AUTO;
+static int __init eager_fpu_setup(char *s)
+{
+ if (!strcmp(s, "on"))
+ eagerfpu = ENABLE;
+ else if (!strcmp(s, "off"))
+ eagerfpu = DISABLE;
+ else if (!strcmp(s, "auto"))
+ eagerfpu = AUTO;
+ return 1;
+}
+__setup("eagerfpu=", eager_fpu_setup);
+
+
+/*
+ * Calculate total size of enabled xstates in XCR0/pcntxt_mask.
+ */
+static void __init init_xstate_size(void)
+{
+ unsigned int eax, ebx, ecx, edx;
+ int i;
+
+ if (!cpu_has_xsaves) {
+ cpuid_count(XSTATE_CPUID, 0, &eax, &ebx, &ecx, &edx);
+ xstate_size = ebx;
+ return;
+ }
+
+ xstate_size = FXSAVE_SIZE + XSAVE_HDR_SIZE;
+ for (i = 2; i < 64; i++) {
+ if (test_bit(i, (unsigned long *)&pcntxt_mask)) {
+ cpuid_count(XSTATE_CPUID, i, &eax, &ebx, &ecx, &edx);
+ xstate_size += eax;
+ }
+ }
+}
+
+/*
+ * Enable and initialize the xsave feature.
+ */
+static void __init xstate_enable_boot_cpu(void)
+{
+ unsigned int eax, ebx, ecx, edx;
+
+ if (boot_cpu_data.cpuid_level < XSTATE_CPUID) {
+ WARN(1, KERN_ERR "XSTATE_CPUID missing\n");
+ return;
+ }
+
+ cpuid_count(XSTATE_CPUID, 0, &eax, &ebx, &ecx, &edx);
+ pcntxt_mask = eax + ((u64)edx << 32);
+
+ if ((pcntxt_mask & XSTATE_FPSSE) != XSTATE_FPSSE) {
+ pr_err("FP/SSE not shown under xsave features 0x%llx\n",
+ pcntxt_mask);
+ BUG();
+ }
+
+ /*
+ * Support only the state known to OS.
+ */
+ pcntxt_mask = pcntxt_mask & XCNTXT_MASK;
+
+ xstate_enable();
+
+ /*
+ * Recompute the context size for enabled features
+ */
+ init_xstate_size();
+
+ update_regset_xstate_info(xstate_size, pcntxt_mask);
+ prepare_fx_sw_frame();
+ setup_init_fpu_buf();
+
+ /* Auto enable eagerfpu for xsaveopt */
+ if (cpu_has_xsaveopt && eagerfpu != DISABLE)
+ eagerfpu = ENABLE;
+
+ if (pcntxt_mask & XSTATE_EAGER) {
+ if (eagerfpu == DISABLE) {
+ pr_err("eagerfpu not present, disabling some xstate features: 0x%llx\n",
+ pcntxt_mask & XSTATE_EAGER);
+ pcntxt_mask &= ~XSTATE_EAGER;
+ } else {
+ eagerfpu = ENABLE;
+ }
+ }
+
+ pr_info("enabled xstate_bv 0x%llx, cntxt size 0x%x using %s\n",
+ pcntxt_mask, xstate_size,
+ cpu_has_xsaves ? "compacted form" : "standard form");
+}
+
+/*
+ * For the very first instance, this calls xstate_enable_boot_cpu();
+ * for all subsequent instances, this calls xstate_enable().
+ *
+ * This is somewhat obfuscated due to the lack of powerful enough
+ * overrides for the section checks.
+ */
+void xsave_init(void)
+{
+ static __refdata void (*next_func)(void) = xstate_enable_boot_cpu;
+ void (*this_func)(void);
+
+ if (!cpu_has_xsave)
+ return;
+
+ this_func = next_func;
+ next_func = xstate_enable;
+ this_func();
+}
+
+/*
+ * setup_init_fpu_buf() is __init and it is OK to call it here because
+ * init_xstate_buf will be unset only once during boot.
+ */
+void __init_refok eager_fpu_init(void)
+{
+ WARN_ON(used_math());
+ current_thread_info()->status = 0;
+
+ if (eagerfpu == ENABLE)
+ setup_force_cpu_cap(X86_FEATURE_EAGER_FPU);
+
+ if (!cpu_has_eager_fpu) {
+ stts();
+ return;
+ }
+
+ if (!init_xstate_buf)
+ setup_init_fpu_buf();
+}
+
+/*
+ * Given the xsave area and a state inside, this function returns the
+ * address of the state.
+ *
+ * This is the API that is called to get xstate address in either
+ * standard format or compacted format of xsave area.
+ *
+ * Inputs:
+ * xsave: base address of the xsave area;
+ * xstate: state which is defined in xsave.h (e.g. XSTATE_FP, XSTATE_SSE,
+ * etc.)
+ * Output:
+ * address of the state in the xsave area.
+ */
+void *get_xsave_addr(struct xsave_struct *xsave, int xstate)
+{
+ int feature = fls64(xstate) - 1;
+ if (!test_bit(feature, (unsigned long *)&pcntxt_mask))
+ return NULL;
+
+ return (void *)xsave + xstate_comp_offsets[feature];
+}
+EXPORT_SYMBOL_GPL(get_xsave_addr);
+++ /dev/null
-/*
- * Copyright (C) 1994 Linus Torvalds
- *
- * Pentium III FXSR, SSE support
- * General FPU state handling cleanups
- * Gareth Hughes <gareth@valinux.com>, May 2000
- */
-#include <linux/module.h>
-#include <linux/regset.h>
-#include <linux/sched.h>
-#include <linux/slab.h>
-
-#include <asm/sigcontext.h>
-#include <asm/processor.h>
-#include <asm/math_emu.h>
-#include <asm/tlbflush.h>
-#include <asm/uaccess.h>
-#include <asm/ptrace.h>
-#include <asm/i387.h>
-#include <asm/fpu-internal.h>
-#include <asm/user.h>
-
-static DEFINE_PER_CPU(bool, in_kernel_fpu);
-
-void kernel_fpu_disable(void)
-{
- WARN_ON(this_cpu_read(in_kernel_fpu));
- this_cpu_write(in_kernel_fpu, true);
-}
-
-void kernel_fpu_enable(void)
-{
- this_cpu_write(in_kernel_fpu, false);
-}
-
-/*
- * Were we in an interrupt that interrupted kernel mode?
- *
- * On others, we can do a kernel_fpu_begin/end() pair *ONLY* if that
- * pair does nothing at all: the thread must not have fpu (so
- * that we don't try to save the FPU state), and TS must
- * be set (so that the clts/stts pair does nothing that is
- * visible in the interrupted kernel thread).
- *
- * Except for the eagerfpu case when we return true; in the likely case
- * the thread has FPU but we are not going to set/clear TS.
- */
-static inline bool interrupted_kernel_fpu_idle(void)
-{
- if (this_cpu_read(in_kernel_fpu))
- return false;
-
- if (use_eager_fpu())
- return true;
-
- return !__thread_has_fpu(current) &&
- (read_cr0() & X86_CR0_TS);
-}
-
-/*
- * Were we in user mode (or vm86 mode) when we were
- * interrupted?
- *
- * Doing kernel_fpu_begin/end() is ok if we are running
- * in an interrupt context from user mode - we'll just
- * save the FPU state as required.
- */
-static inline bool interrupted_user_mode(void)
-{
- struct pt_regs *regs = get_irq_regs();
- return regs && user_mode(regs);
-}
-
-/*
- * Can we use the FPU in kernel mode with the
- * whole "kernel_fpu_begin/end()" sequence?
- *
- * It's always ok in process context (ie "not interrupt")
- * but it is sometimes ok even from an irq.
- */
-bool irq_fpu_usable(void)
-{
- return !in_interrupt() ||
- interrupted_user_mode() ||
- interrupted_kernel_fpu_idle();
-}
-EXPORT_SYMBOL(irq_fpu_usable);
-
-void __kernel_fpu_begin(void)
-{
- struct task_struct *me = current;
-
- this_cpu_write(in_kernel_fpu, true);
-
- if (__thread_has_fpu(me)) {
- __save_init_fpu(me);
- } else {
- this_cpu_write(fpu_owner_task, NULL);
- if (!use_eager_fpu())
- clts();
- }
-}
-EXPORT_SYMBOL(__kernel_fpu_begin);
-
-void __kernel_fpu_end(void)
-{
- struct task_struct *me = current;
-
- if (__thread_has_fpu(me)) {
- if (WARN_ON(restore_fpu_checking(me)))
- fpu_reset_state(me);
- } else if (!use_eager_fpu()) {
- stts();
- }
-
- this_cpu_write(in_kernel_fpu, false);
-}
-EXPORT_SYMBOL(__kernel_fpu_end);
-
-/*
- * Save the FPU state (initialize it if necessary):
- *
- * This only ever gets called for the current task.
- */
-void fpu__save(struct task_struct *tsk)
-{
- WARN_ON(tsk != current);
-
- preempt_disable();
- if (__thread_has_fpu(tsk)) {
- if (use_eager_fpu()) {
- __save_fpu(tsk);
- } else {
- __save_init_fpu(tsk);
- __thread_fpu_end(tsk);
- }
- }
- preempt_enable();
-}
-EXPORT_SYMBOL_GPL(fpu__save);
-
-unsigned int mxcsr_feature_mask __read_mostly = 0xffffffffu;
-unsigned int xstate_size;
-EXPORT_SYMBOL_GPL(xstate_size);
-static struct i387_fxsave_struct fx_scratch;
-
-static void mxcsr_feature_mask_init(void)
-{
- unsigned long mask = 0;
-
- if (cpu_has_fxsr) {
- memset(&fx_scratch, 0, sizeof(struct i387_fxsave_struct));
- asm volatile("fxsave %0" : "+m" (fx_scratch));
- mask = fx_scratch.mxcsr_mask;
- if (mask == 0)
- mask = 0x0000ffbf;
- }
- mxcsr_feature_mask &= mask;
-}
-
-static void fpstate_xstate_init_size(void)
-{
- /*
- * Note that xstate_size might be overwriten later during
- * xsave_init().
- */
-
- if (!cpu_has_fpu) {
- /*
- * Disable xsave as we do not support it if i387
- * emulation is enabled.
- */
- setup_clear_cpu_cap(X86_FEATURE_XSAVE);
- setup_clear_cpu_cap(X86_FEATURE_XSAVEOPT);
- xstate_size = sizeof(struct i387_soft_struct);
- return;
- }
-
- if (cpu_has_fxsr)
- xstate_size = sizeof(struct i387_fxsave_struct);
- else
- xstate_size = sizeof(struct i387_fsave_struct);
-}
-
-/*
- * Called on the boot CPU at bootup to set up the initial FPU state that
- * is later cloned into all processes.
- *
- * Also called on secondary CPUs to set up the FPU state of their
- * idle threads.
- */
-void fpu__cpu_init(void)
-{
- unsigned long cr0;
- unsigned long cr4_mask = 0;
-
-#ifndef CONFIG_MATH_EMULATION
- if (!cpu_has_fpu) {
- pr_emerg("No FPU found and no math emulation present\n");
- pr_emerg("Giving up\n");
- for (;;)
- asm volatile("hlt");
- }
-#endif
- if (cpu_has_fxsr)
- cr4_mask |= X86_CR4_OSFXSR;
- if (cpu_has_xmm)
- cr4_mask |= X86_CR4_OSXMMEXCPT;
- if (cr4_mask)
- cr4_set_bits(cr4_mask);
-
- cr0 = read_cr0();
- cr0 &= ~(X86_CR0_TS|X86_CR0_EM); /* clear TS and EM */
- if (!cpu_has_fpu)
- cr0 |= X86_CR0_EM;
- write_cr0(cr0);
-
- /*
- * fpstate_xstate_init_size() is only called once, to avoid overriding
- * 'xstate_size' during (secondary CPU) bootup or during CPU hotplug.
- */
- if (xstate_size == 0)
- fpstate_xstate_init_size();
-
- mxcsr_feature_mask_init();
- xsave_init();
- eager_fpu_init();
-}
-
-void fpstate_init(struct fpu *fpu)
-{
- if (!cpu_has_fpu) {
- finit_soft_fpu(&fpu->state->soft);
- return;
- }
-
- memset(fpu->state, 0, xstate_size);
-
- if (cpu_has_fxsr) {
- fx_finit(&fpu->state->fxsave);
- } else {
- struct i387_fsave_struct *fp = &fpu->state->fsave;
- fp->cwd = 0xffff037fu;
- fp->swd = 0xffff0000u;
- fp->twd = 0xffffffffu;
- fp->fos = 0xffff0000u;
- }
-}
-EXPORT_SYMBOL_GPL(fpstate_init);
-
-int fpstate_alloc(struct fpu *fpu)
-{
- if (fpu->state)
- return 0;
-
- fpu->state = kmem_cache_alloc(task_xstate_cachep, GFP_KERNEL);
- if (!fpu->state)
- return -ENOMEM;
-
- /* The CPU requires the FPU state to be aligned to 16 byte boundaries: */
- WARN_ON((unsigned long)fpu->state & 15);
-
- return 0;
-}
-EXPORT_SYMBOL_GPL(fpstate_alloc);
-
-/*
- * Allocate the backing store for the current task's FPU registers
- * and initialize the registers themselves as well.
- *
- * Can fail.
- */
-int fpstate_alloc_init(struct task_struct *curr)
-{
- int ret;
-
- if (WARN_ON_ONCE(curr != current))
- return -EINVAL;
- if (WARN_ON_ONCE(curr->flags & PF_USED_MATH))
- return -EINVAL;
-
- /*
- * Memory allocation at the first usage of the FPU and other state.
- */
- ret = fpstate_alloc(&curr->thread.fpu);
- if (ret)
- return ret;
-
- fpstate_init(&curr->thread.fpu);
-
- /* Safe to do for the current task: */
- curr->flags |= PF_USED_MATH;
-
- return 0;
-}
-EXPORT_SYMBOL_GPL(fpstate_alloc_init);
-
-/*
- * The _current_ task is using the FPU for the first time
- * so initialize it and set the mxcsr to its default
- * value at reset if we support XMM instructions and then
- * remember the current task has used the FPU.
- */
-static int fpu__unlazy_stopped(struct task_struct *child)
-{
- int ret;
-
- if (WARN_ON_ONCE(child == current))
- return -EINVAL;
-
- if (child->flags & PF_USED_MATH) {
- task_disable_lazy_fpu_restore(child);
- return 0;
- }
-
- /*
- * Memory allocation at the first usage of the FPU and other state.
- */
- ret = fpstate_alloc(&child->thread.fpu);
- if (ret)
- return ret;
-
- fpstate_init(&child->thread.fpu);
-
- /* Safe to do for stopped child tasks: */
- child->flags |= PF_USED_MATH;
-
- return 0;
-}
-
-/*
- * The xstateregs_active() routine is the same as the fpregs_active() routine,
- * as the "regset->n" for the xstate regset will be updated based on the feature
- * capabilites supported by the xsave.
- */
-int fpregs_active(struct task_struct *target, const struct user_regset *regset)
-{
- return tsk_used_math(target) ? regset->n : 0;
-}
-
-int xfpregs_active(struct task_struct *target, const struct user_regset *regset)
-{
- return (cpu_has_fxsr && tsk_used_math(target)) ? regset->n : 0;
-}
-
-int xfpregs_get(struct task_struct *target, const struct user_regset *regset,
- unsigned int pos, unsigned int count,
- void *kbuf, void __user *ubuf)
-{
- int ret;
-
- if (!cpu_has_fxsr)
- return -ENODEV;
-
- ret = fpu__unlazy_stopped(target);
- if (ret)
- return ret;
-
- sanitize_i387_state(target);
-
- return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
- &target->thread.fpu.state->fxsave, 0, -1);
-}
-
-int xfpregs_set(struct task_struct *target, const struct user_regset *regset,
- unsigned int pos, unsigned int count,
- const void *kbuf, const void __user *ubuf)
-{
- int ret;
-
- if (!cpu_has_fxsr)
- return -ENODEV;
-
- ret = fpu__unlazy_stopped(target);
- if (ret)
- return ret;
-
- sanitize_i387_state(target);
-
- ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
- &target->thread.fpu.state->fxsave, 0, -1);
-
- /*
- * mxcsr reserved bits must be masked to zero for security reasons.
- */
- target->thread.fpu.state->fxsave.mxcsr &= mxcsr_feature_mask;
-
- /*
- * update the header bits in the xsave header, indicating the
- * presence of FP and SSE state.
- */
- if (cpu_has_xsave)
- target->thread.fpu.state->xsave.xsave_hdr.xstate_bv |= XSTATE_FPSSE;
-
- return ret;
-}
-
-int xstateregs_get(struct task_struct *target, const struct user_regset *regset,
- unsigned int pos, unsigned int count,
- void *kbuf, void __user *ubuf)
-{
- struct xsave_struct *xsave;
- int ret;
-
- if (!cpu_has_xsave)
- return -ENODEV;
-
- ret = fpu__unlazy_stopped(target);
- if (ret)
- return ret;
-
- xsave = &target->thread.fpu.state->xsave;
-
- /*
- * Copy the 48bytes defined by the software first into the xstate
- * memory layout in the thread struct, so that we can copy the entire
- * xstateregs to the user using one user_regset_copyout().
- */
- memcpy(&xsave->i387.sw_reserved,
- xstate_fx_sw_bytes, sizeof(xstate_fx_sw_bytes));
- /*
- * Copy the xstate memory layout.
- */
- ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, xsave, 0, -1);
- return ret;
-}
-
-int xstateregs_set(struct task_struct *target, const struct user_regset *regset,
- unsigned int pos, unsigned int count,
- const void *kbuf, const void __user *ubuf)
-{
- struct xsave_struct *xsave;
- int ret;
-
- if (!cpu_has_xsave)
- return -ENODEV;
-
- ret = fpu__unlazy_stopped(target);
- if (ret)
- return ret;
-
- xsave = &target->thread.fpu.state->xsave;
-
- ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, xsave, 0, -1);
- /*
- * mxcsr reserved bits must be masked to zero for security reasons.
- */
- xsave->i387.mxcsr &= mxcsr_feature_mask;
- xsave->xsave_hdr.xstate_bv &= pcntxt_mask;
- /*
- * These bits must be zero.
- */
- memset(&xsave->xsave_hdr.reserved, 0, 48);
- return ret;
-}
-
-#if defined CONFIG_X86_32 || defined CONFIG_IA32_EMULATION
-
-/*
- * FPU tag word conversions.
- */
-
-static inline unsigned short twd_i387_to_fxsr(unsigned short twd)
-{
- unsigned int tmp; /* to avoid 16 bit prefixes in the code */
-
- /* Transform each pair of bits into 01 (valid) or 00 (empty) */
- tmp = ~twd;
- tmp = (tmp | (tmp>>1)) & 0x5555; /* 0V0V0V0V0V0V0V0V */
- /* and move the valid bits to the lower byte. */
- tmp = (tmp | (tmp >> 1)) & 0x3333; /* 00VV00VV00VV00VV */
- tmp = (tmp | (tmp >> 2)) & 0x0f0f; /* 0000VVVV0000VVVV */
- tmp = (tmp | (tmp >> 4)) & 0x00ff; /* 00000000VVVVVVVV */
-
- return tmp;
-}
-
-#define FPREG_ADDR(f, n) ((void *)&(f)->st_space + (n) * 16)
-#define FP_EXP_TAG_VALID 0
-#define FP_EXP_TAG_ZERO 1
-#define FP_EXP_TAG_SPECIAL 2
-#define FP_EXP_TAG_EMPTY 3
-
-static inline u32 twd_fxsr_to_i387(struct i387_fxsave_struct *fxsave)
-{
- struct _fpxreg *st;
- u32 tos = (fxsave->swd >> 11) & 7;
- u32 twd = (unsigned long) fxsave->twd;
- u32 tag;
- u32 ret = 0xffff0000u;
- int i;
-
- for (i = 0; i < 8; i++, twd >>= 1) {
- if (twd & 0x1) {
- st = FPREG_ADDR(fxsave, (i - tos) & 7);
-
- switch (st->exponent & 0x7fff) {
- case 0x7fff:
- tag = FP_EXP_TAG_SPECIAL;
- break;
- case 0x0000:
- if (!st->significand[0] &&
- !st->significand[1] &&
- !st->significand[2] &&
- !st->significand[3])
- tag = FP_EXP_TAG_ZERO;
- else
- tag = FP_EXP_TAG_SPECIAL;
- break;
- default:
- if (st->significand[3] & 0x8000)
- tag = FP_EXP_TAG_VALID;
- else
- tag = FP_EXP_TAG_SPECIAL;
- break;
- }
- } else {
- tag = FP_EXP_TAG_EMPTY;
- }
- ret |= tag << (2 * i);
- }
- return ret;
-}
-
-/*
- * FXSR floating point environment conversions.
- */
-
-void
-convert_from_fxsr(struct user_i387_ia32_struct *env, struct task_struct *tsk)
-{
- struct i387_fxsave_struct *fxsave = &tsk->thread.fpu.state->fxsave;
- struct _fpreg *to = (struct _fpreg *) &env->st_space[0];
- struct _fpxreg *from = (struct _fpxreg *) &fxsave->st_space[0];
- int i;
-
- env->cwd = fxsave->cwd | 0xffff0000u;
- env->swd = fxsave->swd | 0xffff0000u;
- env->twd = twd_fxsr_to_i387(fxsave);
-
-#ifdef CONFIG_X86_64
- env->fip = fxsave->rip;
- env->foo = fxsave->rdp;
- /*
- * should be actually ds/cs at fpu exception time, but
- * that information is not available in 64bit mode.
- */
- env->fcs = task_pt_regs(tsk)->cs;
- if (tsk == current) {
- savesegment(ds, env->fos);
- } else {
- env->fos = tsk->thread.ds;
- }
- env->fos |= 0xffff0000;
-#else
- env->fip = fxsave->fip;
- env->fcs = (u16) fxsave->fcs | ((u32) fxsave->fop << 16);
- env->foo = fxsave->foo;
- env->fos = fxsave->fos;
-#endif
-
- for (i = 0; i < 8; ++i)
- memcpy(&to[i], &from[i], sizeof(to[0]));
-}
-
-void convert_to_fxsr(struct task_struct *tsk,
- const struct user_i387_ia32_struct *env)
-
-{
- struct i387_fxsave_struct *fxsave = &tsk->thread.fpu.state->fxsave;
- struct _fpreg *from = (struct _fpreg *) &env->st_space[0];
- struct _fpxreg *to = (struct _fpxreg *) &fxsave->st_space[0];
- int i;
-
- fxsave->cwd = env->cwd;
- fxsave->swd = env->swd;
- fxsave->twd = twd_i387_to_fxsr(env->twd);
- fxsave->fop = (u16) ((u32) env->fcs >> 16);
-#ifdef CONFIG_X86_64
- fxsave->rip = env->fip;
- fxsave->rdp = env->foo;
- /* cs and ds ignored */
-#else
- fxsave->fip = env->fip;
- fxsave->fcs = (env->fcs & 0xffff);
- fxsave->foo = env->foo;
- fxsave->fos = env->fos;
-#endif
-
- for (i = 0; i < 8; ++i)
- memcpy(&to[i], &from[i], sizeof(from[0]));
-}
-
-int fpregs_get(struct task_struct *target, const struct user_regset *regset,
- unsigned int pos, unsigned int count,
- void *kbuf, void __user *ubuf)
-{
- struct user_i387_ia32_struct env;
- int ret;
-
- ret = fpu__unlazy_stopped(target);
- if (ret)
- return ret;
-
- if (!static_cpu_has(X86_FEATURE_FPU))
- return fpregs_soft_get(target, regset, pos, count, kbuf, ubuf);
-
- if (!cpu_has_fxsr)
- return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
- &target->thread.fpu.state->fsave, 0,
- -1);
-
- sanitize_i387_state(target);
-
- if (kbuf && pos == 0 && count == sizeof(env)) {
- convert_from_fxsr(kbuf, target);
- return 0;
- }
-
- convert_from_fxsr(&env, target);
-
- return user_regset_copyout(&pos, &count, &kbuf, &ubuf, &env, 0, -1);
-}
-
-int fpregs_set(struct task_struct *target, const struct user_regset *regset,
- unsigned int pos, unsigned int count,
- const void *kbuf, const void __user *ubuf)
-{
- struct user_i387_ia32_struct env;
- int ret;
-
- ret = fpu__unlazy_stopped(target);
- if (ret)
- return ret;
-
- sanitize_i387_state(target);
-
- if (!static_cpu_has(X86_FEATURE_FPU))
- return fpregs_soft_set(target, regset, pos, count, kbuf, ubuf);
-
- if (!cpu_has_fxsr)
- return user_regset_copyin(&pos, &count, &kbuf, &ubuf,
- &target->thread.fpu.state->fsave, 0,
- -1);
-
- if (pos > 0 || count < sizeof(env))
- convert_from_fxsr(&env, target);
-
- ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &env, 0, -1);
- if (!ret)
- convert_to_fxsr(target, &env);
-
- /*
- * update the header bit in the xsave header, indicating the
- * presence of FP.
- */
- if (cpu_has_xsave)
- target->thread.fpu.state->xsave.xsave_hdr.xstate_bv |= XSTATE_FP;
- return ret;
-}
-
-/*
- * FPU state for core dumps.
- * This is only used for a.out dumps now.
- * It is declared generically using elf_fpregset_t (which is
- * struct user_i387_struct) but is in fact only used for 32-bit
- * dumps, so on 64-bit it is really struct user_i387_ia32_struct.
- */
-int dump_fpu(struct pt_regs *regs, struct user_i387_struct *fpu)
-{
- struct task_struct *tsk = current;
- int fpvalid;
-
- fpvalid = !!used_math();
- if (fpvalid)
- fpvalid = !fpregs_get(tsk, NULL,
- 0, sizeof(struct user_i387_ia32_struct),
- fpu, NULL);
-
- return fpvalid;
-}
-EXPORT_SYMBOL(dump_fpu);
-
-#endif /* CONFIG_X86_32 || CONFIG_IA32_EMULATION */
-
-static int __init no_387(char *s)
-{
- setup_clear_cpu_cap(X86_FEATURE_FPU);
- return 1;
-}
-
-__setup("no387", no_387);
-
-/*
- * Set the X86_FEATURE_FPU CPU-capability bit based on
- * trying to execute an actual sequence of FPU instructions:
- */
-void fpu__detect(struct cpuinfo_x86 *c)
-{
- unsigned long cr0;
- u16 fsw, fcw;
-
- fsw = fcw = 0xffff;
-
- cr0 = read_cr0();
- cr0 &= ~(X86_CR0_TS | X86_CR0_EM);
- write_cr0(cr0);
-
- asm volatile("fninit ; fnstsw %0 ; fnstcw %1"
- : "+m" (fsw), "+m" (fcw));
-
- if (fsw == 0 && (fcw & 0x103f) == 0x003f)
- set_cpu_cap(c, X86_FEATURE_FPU);
- else
- clear_cpu_cap(c, X86_FEATURE_FPU);
-
- /* The final cr0 value is set in fpu_init() */
-}
+++ /dev/null
-/*
- * xsave/xrstor support.
- *
- * Author: Suresh Siddha <suresh.b.siddha@intel.com>
- */
-
-#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
-
-#include <linux/bootmem.h>
-#include <linux/compat.h>
-#include <linux/cpu.h>
-#include <asm/i387.h>
-#include <asm/fpu-internal.h>
-#include <asm/sigframe.h>
-#include <asm/tlbflush.h>
-#include <asm/xcr.h>
-
-/*
- * Supported feature mask by the CPU and the kernel.
- */
-u64 pcntxt_mask;
-
-/*
- * Represents init state for the supported extended state.
- */
-struct xsave_struct *init_xstate_buf;
-
-static struct _fpx_sw_bytes fx_sw_reserved, fx_sw_reserved_ia32;
-static unsigned int *xstate_offsets, *xstate_sizes;
-static unsigned int xstate_comp_offsets[sizeof(pcntxt_mask)*8];
-static unsigned int xstate_features;
-
-/*
- * If a processor implementation discern that a processor state component is
- * in its initialized state it may modify the corresponding bit in the
- * xsave_hdr.xstate_bv as '0', with out modifying the corresponding memory
- * layout in the case of xsaveopt. While presenting the xstate information to
- * the user, we always ensure that the memory layout of a feature will be in
- * the init state if the corresponding header bit is zero. This is to ensure
- * that the user doesn't see some stale state in the memory layout during
- * signal handling, debugging etc.
- */
-void __sanitize_i387_state(struct task_struct *tsk)
-{
- struct i387_fxsave_struct *fx = &tsk->thread.fpu.state->fxsave;
- int feature_bit = 0x2;
- u64 xstate_bv;
-
- if (!fx)
- return;
-
- xstate_bv = tsk->thread.fpu.state->xsave.xsave_hdr.xstate_bv;
-
- /*
- * None of the feature bits are in init state. So nothing else
- * to do for us, as the memory layout is up to date.
- */
- if ((xstate_bv & pcntxt_mask) == pcntxt_mask)
- return;
-
- /*
- * FP is in init state
- */
- if (!(xstate_bv & XSTATE_FP)) {
- fx->cwd = 0x37f;
- fx->swd = 0;
- fx->twd = 0;
- fx->fop = 0;
- fx->rip = 0;
- fx->rdp = 0;
- memset(&fx->st_space[0], 0, 128);
- }
-
- /*
- * SSE is in init state
- */
- if (!(xstate_bv & XSTATE_SSE))
- memset(&fx->xmm_space[0], 0, 256);
-
- xstate_bv = (pcntxt_mask & ~xstate_bv) >> 2;
-
- /*
- * Update all the other memory layouts for which the corresponding
- * header bit is in the init state.
- */
- while (xstate_bv) {
- if (xstate_bv & 0x1) {
- int offset = xstate_offsets[feature_bit];
- int size = xstate_sizes[feature_bit];
-
- memcpy(((void *) fx) + offset,
- ((void *) init_xstate_buf) + offset,
- size);
- }
-
- xstate_bv >>= 1;
- feature_bit++;
- }
-}
-
-/*
- * Check for the presence of extended state information in the
- * user fpstate pointer in the sigcontext.
- */
-static inline int check_for_xstate(struct i387_fxsave_struct __user *buf,
- void __user *fpstate,
- struct _fpx_sw_bytes *fx_sw)
-{
- int min_xstate_size = sizeof(struct i387_fxsave_struct) +
- sizeof(struct xsave_hdr_struct);
- unsigned int magic2;
-
- if (__copy_from_user(fx_sw, &buf->sw_reserved[0], sizeof(*fx_sw)))
- return -1;
-
- /* Check for the first magic field and other error scenarios. */
- if (fx_sw->magic1 != FP_XSTATE_MAGIC1 ||
- fx_sw->xstate_size < min_xstate_size ||
- fx_sw->xstate_size > xstate_size ||
- fx_sw->xstate_size > fx_sw->extended_size)
- return -1;
-
- /*
- * Check for the presence of second magic word at the end of memory
- * layout. This detects the case where the user just copied the legacy
- * fpstate layout with out copying the extended state information
- * in the memory layout.
- */
- if (__get_user(magic2, (__u32 __user *)(fpstate + fx_sw->xstate_size))
- || magic2 != FP_XSTATE_MAGIC2)
- return -1;
-
- return 0;
-}
-
-/*
- * Signal frame handlers.
- */
-static inline int save_fsave_header(struct task_struct *tsk, void __user *buf)
-{
- if (use_fxsr()) {
- struct xsave_struct *xsave = &tsk->thread.fpu.state->xsave;
- struct user_i387_ia32_struct env;
- struct _fpstate_ia32 __user *fp = buf;
-
- convert_from_fxsr(&env, tsk);
-
- if (__copy_to_user(buf, &env, sizeof(env)) ||
- __put_user(xsave->i387.swd, &fp->status) ||
- __put_user(X86_FXSR_MAGIC, &fp->magic))
- return -1;
- } else {
- struct i387_fsave_struct __user *fp = buf;
- u32 swd;
- if (__get_user(swd, &fp->swd) || __put_user(swd, &fp->status))
- return -1;
- }
-
- return 0;
-}
-
-static inline int save_xstate_epilog(void __user *buf, int ia32_frame)
-{
- struct xsave_struct __user *x = buf;
- struct _fpx_sw_bytes *sw_bytes;
- u32 xstate_bv;
- int err;
-
- /* Setup the bytes not touched by the [f]xsave and reserved for SW. */
- sw_bytes = ia32_frame ? &fx_sw_reserved_ia32 : &fx_sw_reserved;
- err = __copy_to_user(&x->i387.sw_reserved, sw_bytes, sizeof(*sw_bytes));
-
- if (!use_xsave())
- return err;
-
- err |= __put_user(FP_XSTATE_MAGIC2, (__u32 *)(buf + xstate_size));
-
- /*
- * Read the xstate_bv which we copied (directly from the cpu or
- * from the state in task struct) to the user buffers.
- */
- err |= __get_user(xstate_bv, (__u32 *)&x->xsave_hdr.xstate_bv);
-
- /*
- * For legacy compatible, we always set FP/SSE bits in the bit
- * vector while saving the state to the user context. This will
- * enable us capturing any changes(during sigreturn) to
- * the FP/SSE bits by the legacy applications which don't touch
- * xstate_bv in the xsave header.
- *
- * xsave aware apps can change the xstate_bv in the xsave
- * header as well as change any contents in the memory layout.
- * xrestore as part of sigreturn will capture all the changes.
- */
- xstate_bv |= XSTATE_FPSSE;
-
- err |= __put_user(xstate_bv, (__u32 *)&x->xsave_hdr.xstate_bv);
-
- return err;
-}
-
-static inline int save_user_xstate(struct xsave_struct __user *buf)
-{
- int err;
-
- if (use_xsave())
- err = xsave_user(buf);
- else if (use_fxsr())
- err = fxsave_user((struct i387_fxsave_struct __user *) buf);
- else
- err = fsave_user((struct i387_fsave_struct __user *) buf);
-
- if (unlikely(err) && __clear_user(buf, xstate_size))
- err = -EFAULT;
- return err;
-}
-
-/*
- * Save the fpu, extended register state to the user signal frame.
- *
- * 'buf_fx' is the 64-byte aligned pointer at which the [f|fx|x]save
- * state is copied.
- * 'buf' points to the 'buf_fx' or to the fsave header followed by 'buf_fx'.
- *
- * buf == buf_fx for 64-bit frames and 32-bit fsave frame.
- * buf != buf_fx for 32-bit frames with fxstate.
- *
- * If the fpu, extended register state is live, save the state directly
- * to the user frame pointed by the aligned pointer 'buf_fx'. Otherwise,
- * copy the thread's fpu state to the user frame starting at 'buf_fx'.
- *
- * If this is a 32-bit frame with fxstate, put a fsave header before
- * the aligned state at 'buf_fx'.
- *
- * For [f]xsave state, update the SW reserved fields in the [f]xsave frame
- * indicating the absence/presence of the extended state to the user.
- */
-int save_xstate_sig(void __user *buf, void __user *buf_fx, int size)
-{
- struct xsave_struct *xsave = ¤t->thread.fpu.state->xsave;
- struct task_struct *tsk = current;
- int ia32_fxstate = (buf != buf_fx);
-
- ia32_fxstate &= (config_enabled(CONFIG_X86_32) ||
- config_enabled(CONFIG_IA32_EMULATION));
-
- if (!access_ok(VERIFY_WRITE, buf, size))
- return -EACCES;
-
- if (!static_cpu_has(X86_FEATURE_FPU))
- return fpregs_soft_get(current, NULL, 0,
- sizeof(struct user_i387_ia32_struct), NULL,
- (struct _fpstate_ia32 __user *) buf) ? -1 : 1;
-
- if (user_has_fpu()) {
- /* Save the live register state to the user directly. */
- if (save_user_xstate(buf_fx))
- return -1;
- /* Update the thread's fxstate to save the fsave header. */
- if (ia32_fxstate)
- fpu_fxsave(&tsk->thread.fpu);
- } else {
- sanitize_i387_state(tsk);
- if (__copy_to_user(buf_fx, xsave, xstate_size))
- return -1;
- }
-
- /* Save the fsave header for the 32-bit frames. */
- if ((ia32_fxstate || !use_fxsr()) && save_fsave_header(tsk, buf))
- return -1;
-
- if (use_fxsr() && save_xstate_epilog(buf_fx, ia32_fxstate))
- return -1;
-
- return 0;
-}
-
-static inline void
-sanitize_restored_xstate(struct task_struct *tsk,
- struct user_i387_ia32_struct *ia32_env,
- u64 xstate_bv, int fx_only)
-{
- struct xsave_struct *xsave = &tsk->thread.fpu.state->xsave;
- struct xsave_hdr_struct *xsave_hdr = &xsave->xsave_hdr;
-
- if (use_xsave()) {
- /* These bits must be zero. */
- memset(xsave_hdr->reserved, 0, 48);
-
- /*
- * Init the state that is not present in the memory
- * layout and not enabled by the OS.
- */
- if (fx_only)
- xsave_hdr->xstate_bv = XSTATE_FPSSE;
- else
- xsave_hdr->xstate_bv &= (pcntxt_mask & xstate_bv);
- }
-
- if (use_fxsr()) {
- /*
- * mscsr reserved bits must be masked to zero for security
- * reasons.
- */
- xsave->i387.mxcsr &= mxcsr_feature_mask;
-
- convert_to_fxsr(tsk, ia32_env);
- }
-}
-
-/*
- * Restore the extended state if present. Otherwise, restore the FP/SSE state.
- */
-static inline int restore_user_xstate(void __user *buf, u64 xbv, int fx_only)
-{
- if (use_xsave()) {
- if ((unsigned long)buf % 64 || fx_only) {
- u64 init_bv = pcntxt_mask & ~XSTATE_FPSSE;
- xrstor_state(init_xstate_buf, init_bv);
- return fxrstor_user(buf);
- } else {
- u64 init_bv = pcntxt_mask & ~xbv;
- if (unlikely(init_bv))
- xrstor_state(init_xstate_buf, init_bv);
- return xrestore_user(buf, xbv);
- }
- } else if (use_fxsr()) {
- return fxrstor_user(buf);
- } else
- return frstor_user(buf);
-}
-
-int __restore_xstate_sig(void __user *buf, void __user *buf_fx, int size)
-{
- int ia32_fxstate = (buf != buf_fx);
- struct task_struct *tsk = current;
- int state_size = xstate_size;
- u64 xstate_bv = 0;
- int fx_only = 0;
-
- ia32_fxstate &= (config_enabled(CONFIG_X86_32) ||
- config_enabled(CONFIG_IA32_EMULATION));
-
- if (!buf) {
- fpu_reset_state(tsk);
- return 0;
- }
-
- if (!access_ok(VERIFY_READ, buf, size))
- return -EACCES;
-
- if (!used_math() && fpstate_alloc_init(tsk))
- return -1;
-
- if (!static_cpu_has(X86_FEATURE_FPU))
- return fpregs_soft_set(current, NULL,
- 0, sizeof(struct user_i387_ia32_struct),
- NULL, buf) != 0;
-
- if (use_xsave()) {
- struct _fpx_sw_bytes fx_sw_user;
- if (unlikely(check_for_xstate(buf_fx, buf_fx, &fx_sw_user))) {
- /*
- * Couldn't find the extended state information in the
- * memory layout. Restore just the FP/SSE and init all
- * the other extended state.
- */
- state_size = sizeof(struct i387_fxsave_struct);
- fx_only = 1;
- } else {
- state_size = fx_sw_user.xstate_size;
- xstate_bv = fx_sw_user.xstate_bv;
- }
- }
-
- if (ia32_fxstate) {
- /*
- * For 32-bit frames with fxstate, copy the user state to the
- * thread's fpu state, reconstruct fxstate from the fsave
- * header. Sanitize the copied state etc.
- */
- struct fpu *fpu = &tsk->thread.fpu;
- struct user_i387_ia32_struct env;
- int err = 0;
-
- /*
- * Drop the current fpu which clears used_math(). This ensures
- * that any context-switch during the copy of the new state,
- * avoids the intermediate state from getting restored/saved.
- * Thus avoiding the new restored state from getting corrupted.
- * We will be ready to restore/save the state only after
- * set_used_math() is again set.
- */
- drop_fpu(tsk);
-
- if (__copy_from_user(&fpu->state->xsave, buf_fx, state_size) ||
- __copy_from_user(&env, buf, sizeof(env))) {
- fpstate_init(fpu);
- err = -1;
- } else {
- sanitize_restored_xstate(tsk, &env, xstate_bv, fx_only);
- }
-
- set_used_math();
- if (use_eager_fpu()) {
- preempt_disable();
- math_state_restore();
- preempt_enable();
- }
-
- return err;
- } else {
- /*
- * For 64-bit frames and 32-bit fsave frames, restore the user
- * state to the registers directly (with exceptions handled).
- */
- user_fpu_begin();
- if (restore_user_xstate(buf_fx, xstate_bv, fx_only)) {
- fpu_reset_state(tsk);
- return -1;
- }
- }
-
- return 0;
-}
-
-/*
- * Prepare the SW reserved portion of the fxsave memory layout, indicating
- * the presence of the extended state information in the memory layout
- * pointed by the fpstate pointer in the sigcontext.
- * This will be saved when ever the FP and extended state context is
- * saved on the user stack during the signal handler delivery to the user.
- */
-static void prepare_fx_sw_frame(void)
-{
- int fsave_header_size = sizeof(struct i387_fsave_struct);
- int size = xstate_size + FP_XSTATE_MAGIC2_SIZE;
-
- if (config_enabled(CONFIG_X86_32))
- size += fsave_header_size;
-
- fx_sw_reserved.magic1 = FP_XSTATE_MAGIC1;
- fx_sw_reserved.extended_size = size;
- fx_sw_reserved.xstate_bv = pcntxt_mask;
- fx_sw_reserved.xstate_size = xstate_size;
-
- if (config_enabled(CONFIG_IA32_EMULATION)) {
- fx_sw_reserved_ia32 = fx_sw_reserved;
- fx_sw_reserved_ia32.extended_size += fsave_header_size;
- }
-}
-
-/*
- * Enable the extended processor state save/restore feature
- */
-static inline void xstate_enable(void)
-{
- cr4_set_bits(X86_CR4_OSXSAVE);
- xsetbv(XCR_XFEATURE_ENABLED_MASK, pcntxt_mask);
-}
-
-/*
- * Record the offsets and sizes of different state managed by the xsave
- * memory layout.
- */
-static void __init setup_xstate_features(void)
-{
- int eax, ebx, ecx, edx, leaf = 0x2;
-
- xstate_features = fls64(pcntxt_mask);
- xstate_offsets = alloc_bootmem(xstate_features * sizeof(int));
- xstate_sizes = alloc_bootmem(xstate_features * sizeof(int));
-
- do {
- cpuid_count(XSTATE_CPUID, leaf, &eax, &ebx, &ecx, &edx);
-
- if (eax == 0)
- break;
-
- xstate_offsets[leaf] = ebx;
- xstate_sizes[leaf] = eax;
-
- leaf++;
- } while (1);
-}
-
-/*
- * This function sets up offsets and sizes of all extended states in
- * xsave area. This supports both standard format and compacted format
- * of the xsave aread.
- *
- * Input: void
- * Output: void
- */
-void setup_xstate_comp(void)
-{
- unsigned int xstate_comp_sizes[sizeof(pcntxt_mask)*8];
- int i;
-
- /*
- * The FP xstates and SSE xstates are legacy states. They are always
- * in the fixed offsets in the xsave area in either compacted form
- * or standard form.
- */
- xstate_comp_offsets[0] = 0;
- xstate_comp_offsets[1] = offsetof(struct i387_fxsave_struct, xmm_space);
-
- if (!cpu_has_xsaves) {
- for (i = 2; i < xstate_features; i++) {
- if (test_bit(i, (unsigned long *)&pcntxt_mask)) {
- xstate_comp_offsets[i] = xstate_offsets[i];
- xstate_comp_sizes[i] = xstate_sizes[i];
- }
- }
- return;
- }
-
- xstate_comp_offsets[2] = FXSAVE_SIZE + XSAVE_HDR_SIZE;
-
- for (i = 2; i < xstate_features; i++) {
- if (test_bit(i, (unsigned long *)&pcntxt_mask))
- xstate_comp_sizes[i] = xstate_sizes[i];
- else
- xstate_comp_sizes[i] = 0;
-
- if (i > 2)
- xstate_comp_offsets[i] = xstate_comp_offsets[i-1]
- + xstate_comp_sizes[i-1];
-
- }
-}
-
-/*
- * setup the xstate image representing the init state
- */
-static void __init setup_init_fpu_buf(void)
-{
- /*
- * Setup init_xstate_buf to represent the init state of
- * all the features managed by the xsave
- */
- init_xstate_buf = alloc_bootmem_align(xstate_size,
- __alignof__(struct xsave_struct));
- fx_finit(&init_xstate_buf->i387);
-
- if (!cpu_has_xsave)
- return;
-
- setup_xstate_features();
-
- if (cpu_has_xsaves) {
- init_xstate_buf->xsave_hdr.xcomp_bv =
- (u64)1 << 63 | pcntxt_mask;
- init_xstate_buf->xsave_hdr.xstate_bv = pcntxt_mask;
- }
-
- /*
- * Init all the features state with header_bv being 0x0
- */
- xrstor_state_booting(init_xstate_buf, -1);
- /*
- * Dump the init state again. This is to identify the init state
- * of any feature which is not represented by all zero's.
- */
- xsave_state_booting(init_xstate_buf, -1);
-}
-
-static enum { AUTO, ENABLE, DISABLE } eagerfpu = AUTO;
-static int __init eager_fpu_setup(char *s)
-{
- if (!strcmp(s, "on"))
- eagerfpu = ENABLE;
- else if (!strcmp(s, "off"))
- eagerfpu = DISABLE;
- else if (!strcmp(s, "auto"))
- eagerfpu = AUTO;
- return 1;
-}
-__setup("eagerfpu=", eager_fpu_setup);
-
-
-/*
- * Calculate total size of enabled xstates in XCR0/pcntxt_mask.
- */
-static void __init init_xstate_size(void)
-{
- unsigned int eax, ebx, ecx, edx;
- int i;
-
- if (!cpu_has_xsaves) {
- cpuid_count(XSTATE_CPUID, 0, &eax, &ebx, &ecx, &edx);
- xstate_size = ebx;
- return;
- }
-
- xstate_size = FXSAVE_SIZE + XSAVE_HDR_SIZE;
- for (i = 2; i < 64; i++) {
- if (test_bit(i, (unsigned long *)&pcntxt_mask)) {
- cpuid_count(XSTATE_CPUID, i, &eax, &ebx, &ecx, &edx);
- xstate_size += eax;
- }
- }
-}
-
-/*
- * Enable and initialize the xsave feature.
- */
-static void __init xstate_enable_boot_cpu(void)
-{
- unsigned int eax, ebx, ecx, edx;
-
- if (boot_cpu_data.cpuid_level < XSTATE_CPUID) {
- WARN(1, KERN_ERR "XSTATE_CPUID missing\n");
- return;
- }
-
- cpuid_count(XSTATE_CPUID, 0, &eax, &ebx, &ecx, &edx);
- pcntxt_mask = eax + ((u64)edx << 32);
-
- if ((pcntxt_mask & XSTATE_FPSSE) != XSTATE_FPSSE) {
- pr_err("FP/SSE not shown under xsave features 0x%llx\n",
- pcntxt_mask);
- BUG();
- }
-
- /*
- * Support only the state known to OS.
- */
- pcntxt_mask = pcntxt_mask & XCNTXT_MASK;
-
- xstate_enable();
-
- /*
- * Recompute the context size for enabled features
- */
- init_xstate_size();
-
- update_regset_xstate_info(xstate_size, pcntxt_mask);
- prepare_fx_sw_frame();
- setup_init_fpu_buf();
-
- /* Auto enable eagerfpu for xsaveopt */
- if (cpu_has_xsaveopt && eagerfpu != DISABLE)
- eagerfpu = ENABLE;
-
- if (pcntxt_mask & XSTATE_EAGER) {
- if (eagerfpu == DISABLE) {
- pr_err("eagerfpu not present, disabling some xstate features: 0x%llx\n",
- pcntxt_mask & XSTATE_EAGER);
- pcntxt_mask &= ~XSTATE_EAGER;
- } else {
- eagerfpu = ENABLE;
- }
- }
-
- pr_info("enabled xstate_bv 0x%llx, cntxt size 0x%x using %s\n",
- pcntxt_mask, xstate_size,
- cpu_has_xsaves ? "compacted form" : "standard form");
-}
-
-/*
- * For the very first instance, this calls xstate_enable_boot_cpu();
- * for all subsequent instances, this calls xstate_enable().
- *
- * This is somewhat obfuscated due to the lack of powerful enough
- * overrides for the section checks.
- */
-void xsave_init(void)
-{
- static __refdata void (*next_func)(void) = xstate_enable_boot_cpu;
- void (*this_func)(void);
-
- if (!cpu_has_xsave)
- return;
-
- this_func = next_func;
- next_func = xstate_enable;
- this_func();
-}
-
-/*
- * setup_init_fpu_buf() is __init and it is OK to call it here because
- * init_xstate_buf will be unset only once during boot.
- */
-void __init_refok eager_fpu_init(void)
-{
- WARN_ON(used_math());
- current_thread_info()->status = 0;
-
- if (eagerfpu == ENABLE)
- setup_force_cpu_cap(X86_FEATURE_EAGER_FPU);
-
- if (!cpu_has_eager_fpu) {
- stts();
- return;
- }
-
- if (!init_xstate_buf)
- setup_init_fpu_buf();
-}
-
-/*
- * Given the xsave area and a state inside, this function returns the
- * address of the state.
- *
- * This is the API that is called to get xstate address in either
- * standard format or compacted format of xsave area.
- *
- * Inputs:
- * xsave: base address of the xsave area;
- * xstate: state which is defined in xsave.h (e.g. XSTATE_FP, XSTATE_SSE,
- * etc.)
- * Output:
- * address of the state in the xsave area.
- */
-void *get_xsave_addr(struct xsave_struct *xsave, int xstate)
-{
- int feature = fls64(xstate) - 1;
- if (!test_bit(feature, (unsigned long *)&pcntxt_mask))
- return NULL;
-
- return (void *)xsave + xstate_comp_offsets[feature];
-}
-EXPORT_SYMBOL_GPL(get_xsave_addr);
projects / firefly-linux-kernel-4.4.55.git / commitdiff