# Build rules for the FPU support code:
#
-obj-y += init.o bugs.o core.o xsave.o
+obj-y += init.o bugs.o core.o xstate.o
+++ /dev/null
-/*
- * xsave/xrstor support.
- *
- * Author: Suresh Siddha <suresh.b.siddha@intel.com>
- */
-#include <linux/compat.h>
-#include <linux/cpu.h>
-#include <asm/fpu/api.h>
-#include <asm/fpu/internal.h>
-#include <asm/sigframe.h>
-#include <asm/tlbflush.h>
-#include <asm/xcr.h>
-
-/*
- * Mask of xstate features supported by the CPU and the kernel:
- */
-u64 xfeatures_mask;
-
-/*
- * Represents init state for the supported extended state.
- */
-struct xsave_struct init_xstate_ctx;
-
-static struct _fpx_sw_bytes fx_sw_reserved, fx_sw_reserved_ia32;
-static unsigned int xstate_offsets[XFEATURES_NR_MAX], xstate_sizes[XFEATURES_NR_MAX];
-static unsigned int xstate_comp_offsets[sizeof(xfeatures_mask)*8];
-
-/* The number of supported xfeatures in xfeatures_mask: */
-static unsigned int xfeatures_nr;
-
-/*
- * When executing XSAVEOPT (optimized XSAVE), if a processor implementation
- * detects that an FPU state component is still (or is again) in its
- * initialized state, it may clear the corresponding bit in the header.xfeatures
- * field, and can skip the writeout of registers to the corresponding memory layout.
- *
- * This means that when the bit is zero, the state component might still contain
- * some previous - non-initialized register state.
- *
- * Before writing xstate information to user-space we sanitize those components,
- * to 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 user-space 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;
- u64 xfeatures;
-
- if (!fx)
- return;
-
- xfeatures = tsk->thread.fpu.state.xsave.header.xfeatures;
-
- /*
- * 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 ((xfeatures & xfeatures_mask) == xfeatures_mask)
- return;
-
- /*
- * FP is in init state
- */
- if (!(xfeatures & 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 (!(xfeatures & XSTATE_SSE))
- memset(&fx->xmm_space[0], 0, 256);
-
- /*
- * First two features are FPU and SSE, which above we handled
- * in a special way already:
- */
- feature_bit = 0x2;
- xfeatures = (xfeatures_mask & ~xfeatures) >> 2;
-
- /*
- * Update all the remaining memory layouts according to their
- * standard xstate layout, if their header bit is in the init
- * state:
- */
- while (xfeatures) {
- if (xfeatures & 0x1) {
- int offset = xstate_offsets[feature_bit];
- int size = xstate_sizes[feature_bit];
-
- memcpy((void *)fx + offset,
- (void *)&init_xstate_ctx + offset,
- size);
- }
-
- xfeatures >>= 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 xstate_header);
- 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 xfeatures;
- 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 xfeatures which we copied (directly from the cpu or
- * from the state in task struct) to the user buffers.
- */
- err |= __get_user(xfeatures, (__u32 *)&x->header.xfeatures);
-
- /*
- * 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
- * xfeatures in the xsave header.
- *
- * xsave aware apps can change the xfeatures in the xsave
- * header as well as change any contents in the memory layout.
- * xrestore as part of sigreturn will capture all the changes.
- */
- xfeatures |= XSTATE_FPSSE;
-
- err |= __put_user(xfeatures, (__u32 *)&x->header.xfeatures);
-
- 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 xfeatures, int fx_only)
-{
- struct xsave_struct *xsave = &tsk->thread.fpu.state.xsave;
- struct xstate_header *header = &xsave->header;
-
- if (use_xsave()) {
- /* These bits must be zero. */
- memset(header->reserved, 0, 48);
-
- /*
- * Init the state that is not present in the memory
- * layout and not enabled by the OS.
- */
- if (fx_only)
- header->xfeatures = XSTATE_FPSSE;
- else
- header->xfeatures &= (xfeatures_mask & xfeatures);
- }
-
- 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 = xfeatures_mask & ~XSTATE_FPSSE;
- xrstor_state(&init_xstate_ctx, init_bv);
- return fxrstor_user(buf);
- } else {
- u64 init_bv = xfeatures_mask & ~xbv;
- if (unlikely(init_bv))
- xrstor_state(&init_xstate_ctx, 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;
- struct fpu *fpu = &tsk->thread.fpu;
- int state_size = xstate_size;
- u64 xfeatures = 0;
- int fx_only = 0;
-
- ia32_fxstate &= (config_enabled(CONFIG_X86_32) ||
- config_enabled(CONFIG_IA32_EMULATION));
-
- if (!buf) {
- fpu_reset_state(fpu);
- return 0;
- }
-
- if (!access_ok(VERIFY_READ, buf, size))
- return -EACCES;
-
- fpu__activate_curr(fpu);
-
- 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;
- xfeatures = fx_sw_user.xfeatures;
- }
- }
-
- 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 fpu->fpstate_active. 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
- * fpu->fpstate_active is again set.
- */
- drop_fpu(fpu);
-
- 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, xfeatures, fx_only);
- }
-
- fpu->fpstate_active = 1;
- if (use_eager_fpu()) {
- preempt_disable();
- fpu__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, xfeatures, fx_only)) {
- fpu_reset_state(fpu);
- 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.xfeatures = xfeatures_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.
- * Called once per CPU onlining.
- */
-void fpu__init_cpu_xstate(void)
-{
- if (!cpu_has_xsave || !xfeatures_mask)
- return;
-
- cr4_set_bits(X86_CR4_OSXSAVE);
- xsetbv(XCR_XFEATURE_ENABLED_MASK, xfeatures_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;
-
- xfeatures_nr = fls64(xfeatures_mask);
-
- 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);
-}
-
-static void print_xstate_feature(u64 xstate_mask, const char *desc)
-{
- if (xfeatures_mask & xstate_mask) {
- int xstate_feature = fls64(xstate_mask)-1;
-
- pr_info("x86/fpu: Supporting XSAVE feature %2d: '%s'\n", xstate_feature, desc);
- }
-}
-
-/*
- * Print out all the supported xstate features:
- */
-static void print_xstate_features(void)
-{
- print_xstate_feature(XSTATE_FP, "x87 floating point registers");
- print_xstate_feature(XSTATE_SSE, "SSE registers");
- print_xstate_feature(XSTATE_YMM, "AVX registers");
- print_xstate_feature(XSTATE_BNDREGS, "MPX bounds registers");
- print_xstate_feature(XSTATE_BNDCSR, "MPX CSR");
- print_xstate_feature(XSTATE_OPMASK, "AVX-512 opmask");
- print_xstate_feature(XSTATE_ZMM_Hi256, "AVX-512 Hi256");
- print_xstate_feature(XSTATE_Hi16_ZMM, "AVX-512 ZMM_Hi256");
-}
-
-/*
- * 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(xfeatures_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 < xfeatures_nr; i++) {
- if (test_bit(i, (unsigned long *)&xfeatures_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 < xfeatures_nr; i++) {
- if (test_bit(i, (unsigned long *)&xfeatures_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 setup_init_fpu_buf(void)
-{
- static int on_boot_cpu = 1;
-
- if (!on_boot_cpu)
- return;
- on_boot_cpu = 0;
-
- if (!cpu_has_xsave)
- return;
-
- setup_xstate_features();
- print_xstate_features();
-
- if (cpu_has_xsaves) {
- init_xstate_ctx.header.xcomp_bv = (u64)1 << 63 | xfeatures_mask;
- init_xstate_ctx.header.xfeatures = xfeatures_mask;
- }
-
- /*
- * Init all the features state with header_bv being 0x0
- */
- xrstor_state_booting(&init_xstate_ctx, -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_ctx);
-}
-
-/*
- * Calculate total size of enabled xstates in XCR0/xfeatures_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 *)&xfeatures_mask)) {
- cpuid_count(XSTATE_CPUID, i, &eax, &ebx, &ecx, &edx);
- xstate_size += eax;
- }
- }
-}
-
-/*
- * Enable and initialize the xsave feature.
- * Called once per system bootup.
- *
- * ( Not marked __init because of false positive section warnings. )
- */
-void fpu__init_system_xstate(void)
-{
- unsigned int eax, ebx, ecx, edx;
- static bool on_boot_cpu = 1;
-
- if (!on_boot_cpu)
- return;
- on_boot_cpu = 0;
-
- if (!cpu_has_xsave) {
- pr_info("x86/fpu: Legacy x87 FPU detected.\n");
- return;
- }
-
- if (boot_cpu_data.cpuid_level < XSTATE_CPUID) {
- WARN(1, "x86/fpu: XSTATE_CPUID missing!\n");
- return;
- }
-
- cpuid_count(XSTATE_CPUID, 0, &eax, &ebx, &ecx, &edx);
- xfeatures_mask = eax + ((u64)edx << 32);
-
- if ((xfeatures_mask & XSTATE_FPSSE) != XSTATE_FPSSE) {
- pr_err("x86/fpu: FP/SSE not present amongst the CPU's xstate features: 0x%llx.\n", xfeatures_mask);
- BUG();
- }
-
- /*
- * Support only the state known to OS.
- */
- xfeatures_mask = xfeatures_mask & XCNTXT_MASK;
-
- /* Enable xstate instructions to be able to continue with initialization: */
- fpu__init_cpu_xstate();
-
- /*
- * Recompute the context size for enabled features
- */
- init_xstate_size();
-
- update_regset_xstate_info(xstate_size, xfeatures_mask);
- prepare_fx_sw_frame();
- setup_init_fpu_buf();
-
- pr_info("x86/fpu: Enabled xstate features 0x%llx, context size is 0x%x bytes, using '%s' format.\n",
- xfeatures_mask,
- xstate_size,
- cpu_has_xsaves ? "compacted" : "standard");
-}
-
-/*
- * Restore minimal FPU state after suspend:
- */
-void fpu__resume_cpu(void)
-{
- /*
- * Restore XCR0 on xsave capable CPUs:
- */
- if (cpu_has_xsave)
- xsetbv(XCR_XFEATURE_ENABLED_MASK, xfeatures_mask);
-}
-
-/*
- * 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 *)&xfeatures_mask))
- return NULL;
-
- return (void *)xsave + xstate_comp_offsets[feature];
-}
-EXPORT_SYMBOL_GPL(get_xsave_addr);
--- /dev/null
+/*
+ * xsave/xrstor support.
+ *
+ * Author: Suresh Siddha <suresh.b.siddha@intel.com>
+ */
+#include <linux/compat.h>
+#include <linux/cpu.h>
+#include <asm/fpu/api.h>
+#include <asm/fpu/internal.h>
+#include <asm/sigframe.h>
+#include <asm/tlbflush.h>
+#include <asm/xcr.h>
+
+/*
+ * Mask of xstate features supported by the CPU and the kernel:
+ */
+u64 xfeatures_mask;
+
+/*
+ * Represents init state for the supported extended state.
+ */
+struct xsave_struct init_xstate_ctx;
+
+static struct _fpx_sw_bytes fx_sw_reserved, fx_sw_reserved_ia32;
+static unsigned int xstate_offsets[XFEATURES_NR_MAX], xstate_sizes[XFEATURES_NR_MAX];
+static unsigned int xstate_comp_offsets[sizeof(xfeatures_mask)*8];
+
+/* The number of supported xfeatures in xfeatures_mask: */
+static unsigned int xfeatures_nr;
+
+/*
+ * When executing XSAVEOPT (optimized XSAVE), if a processor implementation
+ * detects that an FPU state component is still (or is again) in its
+ * initialized state, it may clear the corresponding bit in the header.xfeatures
+ * field, and can skip the writeout of registers to the corresponding memory layout.
+ *
+ * This means that when the bit is zero, the state component might still contain
+ * some previous - non-initialized register state.
+ *
+ * Before writing xstate information to user-space we sanitize those components,
+ * to 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 user-space 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;
+ u64 xfeatures;
+
+ if (!fx)
+ return;
+
+ xfeatures = tsk->thread.fpu.state.xsave.header.xfeatures;
+
+ /*
+ * 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 ((xfeatures & xfeatures_mask) == xfeatures_mask)
+ return;
+
+ /*
+ * FP is in init state
+ */
+ if (!(xfeatures & 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 (!(xfeatures & XSTATE_SSE))
+ memset(&fx->xmm_space[0], 0, 256);
+
+ /*
+ * First two features are FPU and SSE, which above we handled
+ * in a special way already:
+ */
+ feature_bit = 0x2;
+ xfeatures = (xfeatures_mask & ~xfeatures) >> 2;
+
+ /*
+ * Update all the remaining memory layouts according to their
+ * standard xstate layout, if their header bit is in the init
+ * state:
+ */
+ while (xfeatures) {
+ if (xfeatures & 0x1) {
+ int offset = xstate_offsets[feature_bit];
+ int size = xstate_sizes[feature_bit];
+
+ memcpy((void *)fx + offset,
+ (void *)&init_xstate_ctx + offset,
+ size);
+ }
+
+ xfeatures >>= 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 xstate_header);
+ 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 xfeatures;
+ 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 xfeatures which we copied (directly from the cpu or
+ * from the state in task struct) to the user buffers.
+ */
+ err |= __get_user(xfeatures, (__u32 *)&x->header.xfeatures);
+
+ /*
+ * 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
+ * xfeatures in the xsave header.
+ *
+ * xsave aware apps can change the xfeatures in the xsave
+ * header as well as change any contents in the memory layout.
+ * xrestore as part of sigreturn will capture all the changes.
+ */
+ xfeatures |= XSTATE_FPSSE;
+
+ err |= __put_user(xfeatures, (__u32 *)&x->header.xfeatures);
+
+ 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 xfeatures, int fx_only)
+{
+ struct xsave_struct *xsave = &tsk->thread.fpu.state.xsave;
+ struct xstate_header *header = &xsave->header;
+
+ if (use_xsave()) {
+ /* These bits must be zero. */
+ memset(header->reserved, 0, 48);
+
+ /*
+ * Init the state that is not present in the memory
+ * layout and not enabled by the OS.
+ */
+ if (fx_only)
+ header->xfeatures = XSTATE_FPSSE;
+ else
+ header->xfeatures &= (xfeatures_mask & xfeatures);
+ }
+
+ 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 = xfeatures_mask & ~XSTATE_FPSSE;
+ xrstor_state(&init_xstate_ctx, init_bv);
+ return fxrstor_user(buf);
+ } else {
+ u64 init_bv = xfeatures_mask & ~xbv;
+ if (unlikely(init_bv))
+ xrstor_state(&init_xstate_ctx, 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;
+ struct fpu *fpu = &tsk->thread.fpu;
+ int state_size = xstate_size;
+ u64 xfeatures = 0;
+ int fx_only = 0;
+
+ ia32_fxstate &= (config_enabled(CONFIG_X86_32) ||
+ config_enabled(CONFIG_IA32_EMULATION));
+
+ if (!buf) {
+ fpu_reset_state(fpu);
+ return 0;
+ }
+
+ if (!access_ok(VERIFY_READ, buf, size))
+ return -EACCES;
+
+ fpu__activate_curr(fpu);
+
+ 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;
+ xfeatures = fx_sw_user.xfeatures;
+ }
+ }
+
+ 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 fpu->fpstate_active. 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
+ * fpu->fpstate_active is again set.
+ */
+ drop_fpu(fpu);
+
+ 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, xfeatures, fx_only);
+ }
+
+ fpu->fpstate_active = 1;
+ if (use_eager_fpu()) {
+ preempt_disable();
+ fpu__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, xfeatures, fx_only)) {
+ fpu_reset_state(fpu);
+ 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.xfeatures = xfeatures_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.
+ * Called once per CPU onlining.
+ */
+void fpu__init_cpu_xstate(void)
+{
+ if (!cpu_has_xsave || !xfeatures_mask)
+ return;
+
+ cr4_set_bits(X86_CR4_OSXSAVE);
+ xsetbv(XCR_XFEATURE_ENABLED_MASK, xfeatures_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;
+
+ xfeatures_nr = fls64(xfeatures_mask);
+
+ 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);
+}
+
+static void print_xstate_feature(u64 xstate_mask, const char *desc)
+{
+ if (xfeatures_mask & xstate_mask) {
+ int xstate_feature = fls64(xstate_mask)-1;
+
+ pr_info("x86/fpu: Supporting XSAVE feature %2d: '%s'\n", xstate_feature, desc);
+ }
+}
+
+/*
+ * Print out all the supported xstate features:
+ */
+static void print_xstate_features(void)
+{
+ print_xstate_feature(XSTATE_FP, "x87 floating point registers");
+ print_xstate_feature(XSTATE_SSE, "SSE registers");
+ print_xstate_feature(XSTATE_YMM, "AVX registers");
+ print_xstate_feature(XSTATE_BNDREGS, "MPX bounds registers");
+ print_xstate_feature(XSTATE_BNDCSR, "MPX CSR");
+ print_xstate_feature(XSTATE_OPMASK, "AVX-512 opmask");
+ print_xstate_feature(XSTATE_ZMM_Hi256, "AVX-512 Hi256");
+ print_xstate_feature(XSTATE_Hi16_ZMM, "AVX-512 ZMM_Hi256");
+}
+
+/*
+ * 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(xfeatures_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 < xfeatures_nr; i++) {
+ if (test_bit(i, (unsigned long *)&xfeatures_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 < xfeatures_nr; i++) {
+ if (test_bit(i, (unsigned long *)&xfeatures_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 setup_init_fpu_buf(void)
+{
+ static int on_boot_cpu = 1;
+
+ if (!on_boot_cpu)
+ return;
+ on_boot_cpu = 0;
+
+ if (!cpu_has_xsave)
+ return;
+
+ setup_xstate_features();
+ print_xstate_features();
+
+ if (cpu_has_xsaves) {
+ init_xstate_ctx.header.xcomp_bv = (u64)1 << 63 | xfeatures_mask;
+ init_xstate_ctx.header.xfeatures = xfeatures_mask;
+ }
+
+ /*
+ * Init all the features state with header_bv being 0x0
+ */
+ xrstor_state_booting(&init_xstate_ctx, -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_ctx);
+}
+
+/*
+ * Calculate total size of enabled xstates in XCR0/xfeatures_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 *)&xfeatures_mask)) {
+ cpuid_count(XSTATE_CPUID, i, &eax, &ebx, &ecx, &edx);
+ xstate_size += eax;
+ }
+ }
+}
+
+/*
+ * Enable and initialize the xsave feature.
+ * Called once per system bootup.
+ *
+ * ( Not marked __init because of false positive section warnings. )
+ */
+void fpu__init_system_xstate(void)
+{
+ unsigned int eax, ebx, ecx, edx;
+ static bool on_boot_cpu = 1;
+
+ if (!on_boot_cpu)
+ return;
+ on_boot_cpu = 0;
+
+ if (!cpu_has_xsave) {
+ pr_info("x86/fpu: Legacy x87 FPU detected.\n");
+ return;
+ }
+
+ if (boot_cpu_data.cpuid_level < XSTATE_CPUID) {
+ WARN(1, "x86/fpu: XSTATE_CPUID missing!\n");
+ return;
+ }
+
+ cpuid_count(XSTATE_CPUID, 0, &eax, &ebx, &ecx, &edx);
+ xfeatures_mask = eax + ((u64)edx << 32);
+
+ if ((xfeatures_mask & XSTATE_FPSSE) != XSTATE_FPSSE) {
+ pr_err("x86/fpu: FP/SSE not present amongst the CPU's xstate features: 0x%llx.\n", xfeatures_mask);
+ BUG();
+ }
+
+ /*
+ * Support only the state known to OS.
+ */
+ xfeatures_mask = xfeatures_mask & XCNTXT_MASK;
+
+ /* Enable xstate instructions to be able to continue with initialization: */
+ fpu__init_cpu_xstate();
+
+ /*
+ * Recompute the context size for enabled features
+ */
+ init_xstate_size();
+
+ update_regset_xstate_info(xstate_size, xfeatures_mask);
+ prepare_fx_sw_frame();
+ setup_init_fpu_buf();
+
+ pr_info("x86/fpu: Enabled xstate features 0x%llx, context size is 0x%x bytes, using '%s' format.\n",
+ xfeatures_mask,
+ xstate_size,
+ cpu_has_xsaves ? "compacted" : "standard");
+}
+
+/*
+ * Restore minimal FPU state after suspend:
+ */
+void fpu__resume_cpu(void)
+{
+ /*
+ * Restore XCR0 on xsave capable CPUs:
+ */
+ if (cpu_has_xsave)
+ xsetbv(XCR_XFEATURE_ENABLED_MASK, xfeatures_mask);
+}
+
+/*
+ * 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 *)&xfeatures_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