From: Ingo Molnar Date: Tue, 28 Apr 2015 06:46:23 +0000 (+0200) Subject: x86/fpu: Rename fpu/xsave.c to fpu/xstate.c X-Git-Tag: firefly_0821_release~176^2~1627^2~102 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=62784854502895321d100b1004b486131b9dd286;p=firefly-linux-kernel-4.4.55.git x86/fpu: Rename fpu/xsave.c to fpu/xstate.c Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Dave Hansen Cc: Fenghua Yu Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Oleg Nesterov Cc: Peter Zijlstra Cc: Thomas Gleixner Signed-off-by: Ingo Molnar --- diff --git a/arch/x86/kernel/fpu/Makefile b/arch/x86/kernel/fpu/Makefile index 2020a2b7a597..6ae59bccdd2f 100644 --- a/arch/x86/kernel/fpu/Makefile +++ b/arch/x86/kernel/fpu/Makefile @@ -2,4 +2,4 @@ # 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 diff --git a/arch/x86/kernel/fpu/xsave.c b/arch/x86/kernel/fpu/xsave.c deleted file mode 100644 index f549e2a44336..000000000000 --- a/arch/x86/kernel/fpu/xsave.c +++ /dev/null @@ -1,714 +0,0 @@ -/* - * xsave/xrstor support. - * - * Author: Suresh Siddha - */ -#include -#include -#include -#include -#include -#include -#include - -/* - * 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); diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c new file mode 100644 index 000000000000..f549e2a44336 --- /dev/null +++ b/arch/x86/kernel/fpu/xstate.c @@ -0,0 +1,714 @@ +/* + * xsave/xrstor support. + * + * Author: Suresh Siddha + */ +#include +#include +#include +#include +#include +#include +#include + +/* + * 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);