| // SPDX-License-Identifier: GPL-2.0-only |
| /* |
| * xsave/xrstor support. |
| * |
| * Author: Suresh Siddha <suresh.b.siddha@intel.com> |
| */ |
| #include <linux/compat.h> |
| #include <linux/cpu.h> |
| #include <linux/mman.h> |
| #include <linux/pkeys.h> |
| #include <linux/seq_file.h> |
| #include <linux/proc_fs.h> |
| |
| #include <asm/fpu/api.h> |
| #include <asm/fpu/internal.h> |
| #include <asm/fpu/signal.h> |
| #include <asm/fpu/regset.h> |
| #include <asm/fpu/xstate.h> |
| |
| #include <asm/tlbflush.h> |
| #include <asm/cpufeature.h> |
| |
| /* |
| * Although we spell it out in here, the Processor Trace |
| * xfeature is completely unused. We use other mechanisms |
| * to save/restore PT state in Linux. |
| */ |
| static const char *xfeature_names[] = |
| { |
| "x87 floating point registers" , |
| "SSE registers" , |
| "AVX registers" , |
| "MPX bounds registers" , |
| "MPX CSR" , |
| "AVX-512 opmask" , |
| "AVX-512 Hi256" , |
| "AVX-512 ZMM_Hi256" , |
| "Processor Trace (unused)" , |
| "Protection Keys User registers", |
| "unknown xstate feature" , |
| }; |
| |
| static short xsave_cpuid_features[] __initdata = { |
| X86_FEATURE_FPU, |
| X86_FEATURE_XMM, |
| X86_FEATURE_AVX, |
| X86_FEATURE_MPX, |
| X86_FEATURE_MPX, |
| X86_FEATURE_AVX512F, |
| X86_FEATURE_AVX512F, |
| X86_FEATURE_AVX512F, |
| X86_FEATURE_INTEL_PT, |
| X86_FEATURE_PKU, |
| }; |
| |
| /* |
| * This represents the full set of bits that should ever be set in a kernel |
| * XSAVE buffer, both supervisor and user xstates. |
| */ |
| u64 xfeatures_mask_all __read_mostly; |
| |
| static unsigned int xstate_offsets[XFEATURE_MAX] = { [ 0 ... XFEATURE_MAX - 1] = -1}; |
| static unsigned int xstate_sizes[XFEATURE_MAX] = { [ 0 ... XFEATURE_MAX - 1] = -1}; |
| static unsigned int xstate_comp_offsets[XFEATURE_MAX] = { [ 0 ... XFEATURE_MAX - 1] = -1}; |
| static unsigned int xstate_supervisor_only_offsets[XFEATURE_MAX] = { [ 0 ... XFEATURE_MAX - 1] = -1}; |
| |
| /* |
| * The XSAVE area of kernel can be in standard or compacted format; |
| * it is always in standard format for user mode. This is the user |
| * mode standard format size used for signal and ptrace frames. |
| */ |
| unsigned int fpu_user_xstate_size; |
| |
| /* |
| * Return whether the system supports a given xfeature. |
| * |
| * Also return the name of the (most advanced) feature that the caller requested: |
| */ |
| int cpu_has_xfeatures(u64 xfeatures_needed, const char **feature_name) |
| { |
| u64 xfeatures_missing = xfeatures_needed & ~xfeatures_mask_all; |
| |
| if (unlikely(feature_name)) { |
| long xfeature_idx, max_idx; |
| u64 xfeatures_print; |
| /* |
| * So we use FLS here to be able to print the most advanced |
| * feature that was requested but is missing. So if a driver |
| * asks about "XFEATURE_MASK_SSE | XFEATURE_MASK_YMM" we'll print the |
| * missing AVX feature - this is the most informative message |
| * to users: |
| */ |
| if (xfeatures_missing) |
| xfeatures_print = xfeatures_missing; |
| else |
| xfeatures_print = xfeatures_needed; |
| |
| xfeature_idx = fls64(xfeatures_print)-1; |
| max_idx = ARRAY_SIZE(xfeature_names)-1; |
| xfeature_idx = min(xfeature_idx, max_idx); |
| |
| *feature_name = xfeature_names[xfeature_idx]; |
| } |
| |
| if (xfeatures_missing) |
| return 0; |
| |
| return 1; |
| } |
| EXPORT_SYMBOL_GPL(cpu_has_xfeatures); |
| |
| static bool xfeature_is_supervisor(int xfeature_nr) |
| { |
| /* |
| * Extended State Enumeration Sub-leaves (EAX = 0DH, ECX = n, n > 1) |
| * returns ECX[0] set to (1) for a supervisor state, and cleared (0) |
| * for a user state. |
| */ |
| u32 eax, ebx, ecx, edx; |
| |
| cpuid_count(XSTATE_CPUID, xfeature_nr, &eax, &ebx, &ecx, &edx); |
| return ecx & 1; |
| } |
| |
| /* |
| * When executing XSAVEOPT (or other optimized XSAVE instructions), 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 fpstate_sanitize_xstate(struct fpu *fpu) |
| { |
| struct fxregs_state *fx = &fpu->state.fxsave; |
| int feature_bit; |
| u64 xfeatures; |
| |
| if (!use_xsaveopt()) |
| return; |
| |
| xfeatures = 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_all) == xfeatures_mask_all) |
| return; |
| |
| /* |
| * FP is in init state |
| */ |
| if (!(xfeatures & XFEATURE_MASK_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 & XFEATURE_MASK_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_user() & ~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_comp_offsets[feature_bit]; |
| int size = xstate_sizes[feature_bit]; |
| |
| memcpy((void *)fx + offset, |
| (void *)&init_fpstate.xsave + offset, |
| size); |
| } |
| |
| xfeatures >>= 1; |
| feature_bit++; |
| } |
| } |
| |
| /* |
| * Enable the extended processor state save/restore feature. |
| * Called once per CPU onlining. |
| */ |
| void fpu__init_cpu_xstate(void) |
| { |
| u64 unsup_bits; |
| |
| if (!boot_cpu_has(X86_FEATURE_XSAVE) || !xfeatures_mask_all) |
| return; |
| /* |
| * Unsupported supervisor xstates should not be found in |
| * the xfeatures mask. |
| */ |
| unsup_bits = xfeatures_mask_all & XFEATURE_MASK_SUPERVISOR_UNSUPPORTED; |
| WARN_ONCE(unsup_bits, "x86/fpu: Found unsupported supervisor xstates: 0x%llx\n", |
| unsup_bits); |
| |
| xfeatures_mask_all &= ~XFEATURE_MASK_SUPERVISOR_UNSUPPORTED; |
| |
| cr4_set_bits(X86_CR4_OSXSAVE); |
| |
| /* |
| * XCR_XFEATURE_ENABLED_MASK (aka. XCR0) sets user features |
| * managed by XSAVE{C, OPT, S} and XRSTOR{S}. Only XSAVE user |
| * states can be set here. |
| */ |
| xsetbv(XCR_XFEATURE_ENABLED_MASK, xfeatures_mask_user()); |
| |
| /* |
| * MSR_IA32_XSS sets supervisor states managed by XSAVES. |
| */ |
| if (boot_cpu_has(X86_FEATURE_XSAVES)) |
| wrmsrl(MSR_IA32_XSS, xfeatures_mask_supervisor()); |
| } |
| |
| static bool xfeature_enabled(enum xfeature xfeature) |
| { |
| return xfeatures_mask_all & BIT_ULL(xfeature); |
| } |
| |
| /* |
| * Record the offsets and sizes of various xstates contained |
| * in the XSAVE state memory layout. |
| */ |
| static void __init setup_xstate_features(void) |
| { |
| u32 eax, ebx, ecx, edx, i; |
| /* start at the beginnning of the "extended state" */ |
| unsigned int last_good_offset = offsetof(struct xregs_state, |
| extended_state_area); |
| /* |
| * 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_offsets[XFEATURE_FP] = 0; |
| xstate_sizes[XFEATURE_FP] = offsetof(struct fxregs_state, |
| xmm_space); |
| |
| xstate_offsets[XFEATURE_SSE] = xstate_sizes[XFEATURE_FP]; |
| xstate_sizes[XFEATURE_SSE] = sizeof_field(struct fxregs_state, |
| xmm_space); |
| |
| for (i = FIRST_EXTENDED_XFEATURE; i < XFEATURE_MAX; i++) { |
| if (!xfeature_enabled(i)) |
| continue; |
| |
| cpuid_count(XSTATE_CPUID, i, &eax, &ebx, &ecx, &edx); |
| |
| xstate_sizes[i] = eax; |
| |
| /* |
| * If an xfeature is supervisor state, the offset in EBX is |
| * invalid, leave it to -1. |
| */ |
| if (xfeature_is_supervisor(i)) |
| continue; |
| |
| xstate_offsets[i] = ebx; |
| |
| /* |
| * In our xstate size checks, we assume that the highest-numbered |
| * xstate feature has the highest offset in the buffer. Ensure |
| * it does. |
| */ |
| WARN_ONCE(last_good_offset > xstate_offsets[i], |
| "x86/fpu: misordered xstate at %d\n", last_good_offset); |
| |
| last_good_offset = xstate_offsets[i]; |
| } |
| } |
| |
| static void __init print_xstate_feature(u64 xstate_mask) |
| { |
| const char *feature_name; |
| |
| if (cpu_has_xfeatures(xstate_mask, &feature_name)) |
| pr_info("x86/fpu: Supporting XSAVE feature 0x%03Lx: '%s'\n", xstate_mask, feature_name); |
| } |
| |
| /* |
| * Print out all the supported xstate features: |
| */ |
| static void __init print_xstate_features(void) |
| { |
| print_xstate_feature(XFEATURE_MASK_FP); |
| print_xstate_feature(XFEATURE_MASK_SSE); |
| print_xstate_feature(XFEATURE_MASK_YMM); |
| print_xstate_feature(XFEATURE_MASK_BNDREGS); |
| print_xstate_feature(XFEATURE_MASK_BNDCSR); |
| print_xstate_feature(XFEATURE_MASK_OPMASK); |
| print_xstate_feature(XFEATURE_MASK_ZMM_Hi256); |
| print_xstate_feature(XFEATURE_MASK_Hi16_ZMM); |
| print_xstate_feature(XFEATURE_MASK_PKRU); |
| } |
| |
| /* |
| * This check is important because it is easy to get XSTATE_* |
| * confused with XSTATE_BIT_*. |
| */ |
| #define CHECK_XFEATURE(nr) do { \ |
| WARN_ON(nr < FIRST_EXTENDED_XFEATURE); \ |
| WARN_ON(nr >= XFEATURE_MAX); \ |
| } while (0) |
| |
| /* |
| * We could cache this like xstate_size[], but we only use |
| * it here, so it would be a waste of space. |
| */ |
| static int xfeature_is_aligned(int xfeature_nr) |
| { |
| u32 eax, ebx, ecx, edx; |
| |
| CHECK_XFEATURE(xfeature_nr); |
| |
| if (!xfeature_enabled(xfeature_nr)) { |
| WARN_ONCE(1, "Checking alignment of disabled xfeature %d\n", |
| xfeature_nr); |
| return 0; |
| } |
| |
| cpuid_count(XSTATE_CPUID, xfeature_nr, &eax, &ebx, &ecx, &edx); |
| /* |
| * The value returned by ECX[1] indicates the alignment |
| * of state component 'i' when the compacted format |
| * of the extended region of an XSAVE area is used: |
| */ |
| return !!(ecx & 2); |
| } |
| |
| /* |
| * 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 area. |
| */ |
| static void __init setup_xstate_comp_offsets(void) |
| { |
| unsigned int next_offset; |
| 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[XFEATURE_FP] = 0; |
| xstate_comp_offsets[XFEATURE_SSE] = offsetof(struct fxregs_state, |
| xmm_space); |
| |
| if (!boot_cpu_has(X86_FEATURE_XSAVES)) { |
| for (i = FIRST_EXTENDED_XFEATURE; i < XFEATURE_MAX; i++) { |
| if (xfeature_enabled(i)) |
| xstate_comp_offsets[i] = xstate_offsets[i]; |
| } |
| return; |
| } |
| |
| next_offset = FXSAVE_SIZE + XSAVE_HDR_SIZE; |
| |
| for (i = FIRST_EXTENDED_XFEATURE; i < XFEATURE_MAX; i++) { |
| if (!xfeature_enabled(i)) |
| continue; |
| |
| if (xfeature_is_aligned(i)) |
| next_offset = ALIGN(next_offset, 64); |
| |
| xstate_comp_offsets[i] = next_offset; |
| next_offset += xstate_sizes[i]; |
| } |
| } |
| |
| /* |
| * Setup offsets of a supervisor-state-only XSAVES buffer: |
| * |
| * The offsets stored in xstate_comp_offsets[] only work for one specific |
| * value of the Requested Feature BitMap (RFBM). In cases where a different |
| * RFBM value is used, a different set of offsets is required. This set of |
| * offsets is for when RFBM=xfeatures_mask_supervisor(). |
| */ |
| static void __init setup_supervisor_only_offsets(void) |
| { |
| unsigned int next_offset; |
| int i; |
| |
| next_offset = FXSAVE_SIZE + XSAVE_HDR_SIZE; |
| |
| for (i = FIRST_EXTENDED_XFEATURE; i < XFEATURE_MAX; i++) { |
| if (!xfeature_enabled(i) || !xfeature_is_supervisor(i)) |
| continue; |
| |
| if (xfeature_is_aligned(i)) |
| next_offset = ALIGN(next_offset, 64); |
| |
| xstate_supervisor_only_offsets[i] = next_offset; |
| next_offset += xstate_sizes[i]; |
| } |
| } |
| |
| /* |
| * Print out xstate component offsets and sizes |
| */ |
| static void __init print_xstate_offset_size(void) |
| { |
| int i; |
| |
| for (i = FIRST_EXTENDED_XFEATURE; i < XFEATURE_MAX; i++) { |
| if (!xfeature_enabled(i)) |
| continue; |
| pr_info("x86/fpu: xstate_offset[%d]: %4d, xstate_sizes[%d]: %4d\n", |
| i, xstate_comp_offsets[i], i, xstate_sizes[i]); |
| } |
| } |
| |
| /* |
| * setup the xstate image representing the init state |
| */ |
| static void __init setup_init_fpu_buf(void) |
| { |
| static int on_boot_cpu __initdata = 1; |
| |
| WARN_ON_FPU(!on_boot_cpu); |
| on_boot_cpu = 0; |
| |
| if (!boot_cpu_has(X86_FEATURE_XSAVE)) |
| return; |
| |
| setup_xstate_features(); |
| print_xstate_features(); |
| |
| if (boot_cpu_has(X86_FEATURE_XSAVES)) |
| init_fpstate.xsave.header.xcomp_bv = XCOMP_BV_COMPACTED_FORMAT | |
| xfeatures_mask_all; |
| |
| /* |
| * Init all the features state with header.xfeatures being 0x0 |
| */ |
| copy_kernel_to_xregs_booting(&init_fpstate.xsave); |
| |
| /* |
| * Dump the init state again. This is to identify the init state |
| * of any feature which is not represented by all zero's. |
| */ |
| copy_xregs_to_kernel_booting(&init_fpstate.xsave); |
| } |
| |
| static int xfeature_uncompacted_offset(int xfeature_nr) |
| { |
| u32 eax, ebx, ecx, edx; |
| |
| /* |
| * Only XSAVES supports supervisor states and it uses compacted |
| * format. Checking a supervisor state's uncompacted offset is |
| * an error. |
| */ |
| if (XFEATURE_MASK_SUPERVISOR_ALL & BIT_ULL(xfeature_nr)) { |
| WARN_ONCE(1, "No fixed offset for xstate %d\n", xfeature_nr); |
| return -1; |
| } |
| |
| CHECK_XFEATURE(xfeature_nr); |
| cpuid_count(XSTATE_CPUID, xfeature_nr, &eax, &ebx, &ecx, &edx); |
| return ebx; |
| } |
| |
| static int xfeature_size(int xfeature_nr) |
| { |
| u32 eax, ebx, ecx, edx; |
| |
| CHECK_XFEATURE(xfeature_nr); |
| cpuid_count(XSTATE_CPUID, xfeature_nr, &eax, &ebx, &ecx, &edx); |
| return eax; |
| } |
| |
| /* |
| * 'XSAVES' implies two different things: |
| * 1. saving of supervisor/system state |
| * 2. using the compacted format |
| * |
| * Use this function when dealing with the compacted format so |
| * that it is obvious which aspect of 'XSAVES' is being handled |
| * by the calling code. |
| */ |
| int using_compacted_format(void) |
| { |
| return boot_cpu_has(X86_FEATURE_XSAVES); |
| } |
| |
| /* Validate an xstate header supplied by userspace (ptrace or sigreturn) */ |
| int validate_user_xstate_header(const struct xstate_header *hdr) |
| { |
| /* No unknown or supervisor features may be set */ |
| if (hdr->xfeatures & ~xfeatures_mask_user()) |
| return -EINVAL; |
| |
| /* Userspace must use the uncompacted format */ |
| if (hdr->xcomp_bv) |
| return -EINVAL; |
| |
| /* |
| * If 'reserved' is shrunken to add a new field, make sure to validate |
| * that new field here! |
| */ |
| BUILD_BUG_ON(sizeof(hdr->reserved) != 48); |
| |
| /* No reserved bits may be set */ |
| if (memchr_inv(hdr->reserved, 0, sizeof(hdr->reserved))) |
| return -EINVAL; |
| |
| return 0; |
| } |
| |
| static void __xstate_dump_leaves(void) |
| { |
| int i; |
| u32 eax, ebx, ecx, edx; |
| static int should_dump = 1; |
| |
| if (!should_dump) |
| return; |
| should_dump = 0; |
| /* |
| * Dump out a few leaves past the ones that we support |
| * just in case there are some goodies up there |
| */ |
| for (i = 0; i < XFEATURE_MAX + 10; i++) { |
| cpuid_count(XSTATE_CPUID, i, &eax, &ebx, &ecx, &edx); |
| pr_warn("CPUID[%02x, %02x]: eax=%08x ebx=%08x ecx=%08x edx=%08x\n", |
| XSTATE_CPUID, i, eax, ebx, ecx, edx); |
| } |
| } |
| |
| #define XSTATE_WARN_ON(x) do { \ |
| if (WARN_ONCE(x, "XSAVE consistency problem, dumping leaves")) { \ |
| __xstate_dump_leaves(); \ |
| } \ |
| } while (0) |
| |
| #define XCHECK_SZ(sz, nr, nr_macro, __struct) do { \ |
| if ((nr == nr_macro) && \ |
| WARN_ONCE(sz != sizeof(__struct), \ |
| "%s: struct is %zu bytes, cpu state %d bytes\n", \ |
| __stringify(nr_macro), sizeof(__struct), sz)) { \ |
| __xstate_dump_leaves(); \ |
| } \ |
| } while (0) |
| |
| /* |
| * We have a C struct for each 'xstate'. We need to ensure |
| * that our software representation matches what the CPU |
| * tells us about the state's size. |
| */ |
| static void check_xstate_against_struct(int nr) |
| { |
| /* |
| * Ask the CPU for the size of the state. |
| */ |
| int sz = xfeature_size(nr); |
| /* |
| * Match each CPU state with the corresponding software |
| * structure. |
| */ |
| XCHECK_SZ(sz, nr, XFEATURE_YMM, struct ymmh_struct); |
| XCHECK_SZ(sz, nr, XFEATURE_BNDREGS, struct mpx_bndreg_state); |
| XCHECK_SZ(sz, nr, XFEATURE_BNDCSR, struct mpx_bndcsr_state); |
| XCHECK_SZ(sz, nr, XFEATURE_OPMASK, struct avx_512_opmask_state); |
| XCHECK_SZ(sz, nr, XFEATURE_ZMM_Hi256, struct avx_512_zmm_uppers_state); |
| XCHECK_SZ(sz, nr, XFEATURE_Hi16_ZMM, struct avx_512_hi16_state); |
| XCHECK_SZ(sz, nr, XFEATURE_PKRU, struct pkru_state); |
| |
| /* |
| * Make *SURE* to add any feature numbers in below if |
| * there are "holes" in the xsave state component |
| * numbers. |
| */ |
| if ((nr < XFEATURE_YMM) || |
| (nr >= XFEATURE_MAX) || |
| (nr == XFEATURE_PT_UNIMPLEMENTED_SO_FAR)) { |
| WARN_ONCE(1, "no structure for xstate: %d\n", nr); |
| XSTATE_WARN_ON(1); |
| } |
| } |
| |
| /* |
| * This essentially double-checks what the cpu told us about |
| * how large the XSAVE buffer needs to be. We are recalculating |
| * it to be safe. |
| */ |
| static void do_extra_xstate_size_checks(void) |
| { |
| int paranoid_xstate_size = FXSAVE_SIZE + XSAVE_HDR_SIZE; |
| int i; |
| |
| for (i = FIRST_EXTENDED_XFEATURE; i < XFEATURE_MAX; i++) { |
| if (!xfeature_enabled(i)) |
| continue; |
| |
| check_xstate_against_struct(i); |
| /* |
| * Supervisor state components can be managed only by |
| * XSAVES, which is compacted-format only. |
| */ |
| if (!using_compacted_format()) |
| XSTATE_WARN_ON(xfeature_is_supervisor(i)); |
| |
| /* Align from the end of the previous feature */ |
| if (xfeature_is_aligned(i)) |
| paranoid_xstate_size = ALIGN(paranoid_xstate_size, 64); |
| /* |
| * The offset of a given state in the non-compacted |
| * format is given to us in a CPUID leaf. We check |
| * them for being ordered (increasing offsets) in |
| * setup_xstate_features(). |
| */ |
| if (!using_compacted_format()) |
| paranoid_xstate_size = xfeature_uncompacted_offset(i); |
| /* |
| * The compacted-format offset always depends on where |
| * the previous state ended. |
| */ |
| paranoid_xstate_size += xfeature_size(i); |
| } |
| XSTATE_WARN_ON(paranoid_xstate_size != fpu_kernel_xstate_size); |
| } |
| |
| |
| /* |
| * Get total size of enabled xstates in XCR0 | IA32_XSS. |
| * |
| * Note the SDM's wording here. "sub-function 0" only enumerates |
| * the size of the *user* states. If we use it to size a buffer |
| * that we use 'XSAVES' on, we could potentially overflow the |
| * buffer because 'XSAVES' saves system states too. |
| */ |
| static unsigned int __init get_xsaves_size(void) |
| { |
| unsigned int eax, ebx, ecx, edx; |
| /* |
| * - CPUID function 0DH, sub-function 1: |
| * EBX enumerates the size (in bytes) required by |
| * the XSAVES instruction for an XSAVE area |
| * containing all the state components |
| * corresponding to bits currently set in |
| * XCR0 | IA32_XSS. |
| */ |
| cpuid_count(XSTATE_CPUID, 1, &eax, &ebx, &ecx, &edx); |
| return ebx; |
| } |
| |
| static unsigned int __init get_xsave_size(void) |
| { |
| unsigned int eax, ebx, ecx, edx; |
| /* |
| * - CPUID function 0DH, sub-function 0: |
| * EBX enumerates the size (in bytes) required by |
| * the XSAVE instruction for an XSAVE area |
| * containing all the *user* state components |
| * corresponding to bits currently set in XCR0. |
| */ |
| cpuid_count(XSTATE_CPUID, 0, &eax, &ebx, &ecx, &edx); |
| return ebx; |
| } |
| |
| /* |
| * Will the runtime-enumerated 'xstate_size' fit in the init |
| * task's statically-allocated buffer? |
| */ |
| static bool is_supported_xstate_size(unsigned int test_xstate_size) |
| { |
| if (test_xstate_size <= sizeof(union fpregs_state)) |
| return true; |
| |
| pr_warn("x86/fpu: xstate buffer too small (%zu < %d), disabling xsave\n", |
| sizeof(union fpregs_state), test_xstate_size); |
| return false; |
| } |
| |
| static int __init init_xstate_size(void) |
| { |
| /* Recompute the context size for enabled features: */ |
| unsigned int possible_xstate_size; |
| unsigned int xsave_size; |
| |
| xsave_size = get_xsave_size(); |
| |
| if (boot_cpu_has(X86_FEATURE_XSAVES)) |
| possible_xstate_size = get_xsaves_size(); |
| else |
| possible_xstate_size = xsave_size; |
| |
| /* Ensure we have the space to store all enabled: */ |
| if (!is_supported_xstate_size(possible_xstate_size)) |
| return -EINVAL; |
| |
| /* |
| * The size is OK, we are definitely going to use xsave, |
| * make it known to the world that we need more space. |
| */ |
| fpu_kernel_xstate_size = possible_xstate_size; |
| do_extra_xstate_size_checks(); |
| |
| /* |
| * User space is always in standard format. |
| */ |
| fpu_user_xstate_size = xsave_size; |
| return 0; |
| } |
| |
| /* |
| * We enabled the XSAVE hardware, but something went wrong and |
| * we can not use it. Disable it. |
| */ |
| static void fpu__init_disable_system_xstate(void) |
| { |
| xfeatures_mask_all = 0; |
| cr4_clear_bits(X86_CR4_OSXSAVE); |
| setup_clear_cpu_cap(X86_FEATURE_XSAVE); |
| } |
| |
| /* |
| * Enable and initialize the xsave feature. |
| * Called once per system bootup. |
| */ |
| void __init fpu__init_system_xstate(void) |
| { |
| unsigned int eax, ebx, ecx, edx; |
| static int on_boot_cpu __initdata = 1; |
| int err; |
| int i; |
| |
| WARN_ON_FPU(!on_boot_cpu); |
| on_boot_cpu = 0; |
| |
| if (!boot_cpu_has(X86_FEATURE_FPU)) { |
| pr_info("x86/fpu: No FPU detected\n"); |
| return; |
| } |
| |
| if (!boot_cpu_has(X86_FEATURE_XSAVE)) { |
| pr_info("x86/fpu: x87 FPU will use %s\n", |
| boot_cpu_has(X86_FEATURE_FXSR) ? "FXSAVE" : "FSAVE"); |
| return; |
| } |
| |
| if (boot_cpu_data.cpuid_level < XSTATE_CPUID) { |
| WARN_ON_FPU(1); |
| return; |
| } |
| |
| /* |
| * Find user xstates supported by the processor. |
| */ |
| cpuid_count(XSTATE_CPUID, 0, &eax, &ebx, &ecx, &edx); |
| xfeatures_mask_all = eax + ((u64)edx << 32); |
| |
| /* |
| * Find supervisor xstates supported by the processor. |
| */ |
| cpuid_count(XSTATE_CPUID, 1, &eax, &ebx, &ecx, &edx); |
| xfeatures_mask_all |= ecx + ((u64)edx << 32); |
| |
| if ((xfeatures_mask_user() & XFEATURE_MASK_FPSSE) != XFEATURE_MASK_FPSSE) { |
| /* |
| * This indicates that something really unexpected happened |
| * with the enumeration. Disable XSAVE and try to continue |
| * booting without it. This is too early to BUG(). |
| */ |
| pr_err("x86/fpu: FP/SSE not present amongst the CPU's xstate features: 0x%llx.\n", |
| xfeatures_mask_all); |
| goto out_disable; |
| } |
| |
| /* |
| * Clear XSAVE features that are disabled in the normal CPUID. |
| */ |
| for (i = 0; i < ARRAY_SIZE(xsave_cpuid_features); i++) { |
| if (!boot_cpu_has(xsave_cpuid_features[i])) |
| xfeatures_mask_all &= ~BIT_ULL(i); |
| } |
| |
| xfeatures_mask_all &= fpu__get_supported_xfeatures_mask(); |
| |
| /* Enable xstate instructions to be able to continue with initialization: */ |
| fpu__init_cpu_xstate(); |
| err = init_xstate_size(); |
| if (err) |
| goto out_disable; |
| |
| /* |
| * Update info used for ptrace frames; use standard-format size and no |
| * supervisor xstates: |
| */ |
| update_regset_xstate_info(fpu_user_xstate_size, xfeatures_mask_user()); |
| |
| fpu__init_prepare_fx_sw_frame(); |
| setup_init_fpu_buf(); |
| setup_xstate_comp_offsets(); |
| setup_supervisor_only_offsets(); |
| print_xstate_offset_size(); |
| |
| pr_info("x86/fpu: Enabled xstate features 0x%llx, context size is %d bytes, using '%s' format.\n", |
| xfeatures_mask_all, |
| fpu_kernel_xstate_size, |
| boot_cpu_has(X86_FEATURE_XSAVES) ? "compacted" : "standard"); |
| return; |
| |
| out_disable: |
| /* something went wrong, try to boot without any XSAVE support */ |
| fpu__init_disable_system_xstate(); |
| } |
| |
| /* |
| * Restore minimal FPU state after suspend: |
| */ |
| void fpu__resume_cpu(void) |
| { |
| /* |
| * Restore XCR0 on xsave capable CPUs: |
| */ |
| if (boot_cpu_has(X86_FEATURE_XSAVE)) |
| xsetbv(XCR_XFEATURE_ENABLED_MASK, xfeatures_mask_user()); |
| |
| /* |
| * Restore IA32_XSS. The same CPUID bit enumerates support |
| * of XSAVES and MSR_IA32_XSS. |
| */ |
| if (boot_cpu_has(X86_FEATURE_XSAVES)) |
| wrmsrl(MSR_IA32_XSS, xfeatures_mask_supervisor()); |
| } |
| |
| /* |
| * Given an xstate feature nr, calculate where in the xsave |
| * buffer the state is. Callers should ensure that the buffer |
| * is valid. |
| */ |
| static void *__raw_xsave_addr(struct xregs_state *xsave, int xfeature_nr) |
| { |
| if (!xfeature_enabled(xfeature_nr)) { |
| WARN_ON_FPU(1); |
| return NULL; |
| } |
| |
| return (void *)xsave + xstate_comp_offsets[xfeature_nr]; |
| } |
| /* |
| * 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. |
| * |
| * Note that if there is no data for the field in the xsave buffer |
| * this will return NULL. |
| * |
| * Inputs: |
| * xstate: the thread's storage area for all FPU data |
| * xfeature_nr: state which is defined in xsave.h (e.g. XFEATURE_FP, |
| * XFEATURE_SSE, etc...) |
| * Output: |
| * address of the state in the xsave area, or NULL if the |
| * field is not present in the xsave buffer. |
| */ |
| void *get_xsave_addr(struct xregs_state *xsave, int xfeature_nr) |
| { |
| /* |
| * Do we even *have* xsave state? |
| */ |
| if (!boot_cpu_has(X86_FEATURE_XSAVE)) |
| return NULL; |
| |
| /* |
| * We should not ever be requesting features that we |
| * have not enabled. |
| */ |
| WARN_ONCE(!(xfeatures_mask_all & BIT_ULL(xfeature_nr)), |
| "get of unsupported state"); |
| /* |
| * This assumes the last 'xsave*' instruction to |
| * have requested that 'xfeature_nr' be saved. |
| * If it did not, we might be seeing and old value |
| * of the field in the buffer. |
| * |
| * This can happen because the last 'xsave' did not |
| * request that this feature be saved (unlikely) |
| * or because the "init optimization" caused it |
| * to not be saved. |
| */ |
| if (!(xsave->header.xfeatures & BIT_ULL(xfeature_nr))) |
| return NULL; |
| |
| return __raw_xsave_addr(xsave, xfeature_nr); |
| } |
| EXPORT_SYMBOL_GPL(get_xsave_addr); |
| |
| /* |
| * This wraps up the common operations that need to occur when retrieving |
| * data from xsave state. It first ensures that the current task was |
| * using the FPU and retrieves the data in to a buffer. It then calculates |
| * the offset of the requested field in the buffer. |
| * |
| * This function is safe to call whether the FPU is in use or not. |
| * |
| * Note that this only works on the current task. |
| * |
| * Inputs: |
| * @xfeature_nr: state which is defined in xsave.h (e.g. XFEATURE_FP, |
| * XFEATURE_SSE, etc...) |
| * Output: |
| * address of the state in the xsave area or NULL if the state |
| * is not present or is in its 'init state'. |
| */ |
| const void *get_xsave_field_ptr(int xfeature_nr) |
| { |
| struct fpu *fpu = ¤t->thread.fpu; |
| |
| /* |
| * fpu__save() takes the CPU's xstate registers |
| * and saves them off to the 'fpu memory buffer. |
| */ |
| fpu__save(fpu); |
| |
| return get_xsave_addr(&fpu->state.xsave, xfeature_nr); |
| } |
| |
| #ifdef CONFIG_ARCH_HAS_PKEYS |
| |
| /* |
| * This will go out and modify PKRU register to set the access |
| * rights for @pkey to @init_val. |
| */ |
| int arch_set_user_pkey_access(struct task_struct *tsk, int pkey, |
| unsigned long init_val) |
| { |
| u32 old_pkru; |
| int pkey_shift = (pkey * PKRU_BITS_PER_PKEY); |
| u32 new_pkru_bits = 0; |
| |
| /* |
| * This check implies XSAVE support. OSPKE only gets |
| * set if we enable XSAVE and we enable PKU in XCR0. |
| */ |
| if (!boot_cpu_has(X86_FEATURE_OSPKE)) |
| return -EINVAL; |
| |
| /* |
| * This code should only be called with valid 'pkey' |
| * values originating from in-kernel users. Complain |
| * if a bad value is observed. |
| */ |
| WARN_ON_ONCE(pkey >= arch_max_pkey()); |
| |
| /* Set the bits we need in PKRU: */ |
| if (init_val & PKEY_DISABLE_ACCESS) |
| new_pkru_bits |= PKRU_AD_BIT; |
| if (init_val & PKEY_DISABLE_WRITE) |
| new_pkru_bits |= PKRU_WD_BIT; |
| |
| /* Shift the bits in to the correct place in PKRU for pkey: */ |
| new_pkru_bits <<= pkey_shift; |
| |
| /* Get old PKRU and mask off any old bits in place: */ |
| old_pkru = read_pkru(); |
| old_pkru &= ~((PKRU_AD_BIT|PKRU_WD_BIT) << pkey_shift); |
| |
| /* Write old part along with new part: */ |
| write_pkru(old_pkru | new_pkru_bits); |
| |
| return 0; |
| } |
| #endif /* ! CONFIG_ARCH_HAS_PKEYS */ |
| |
| /* |
| * Weird legacy quirk: SSE and YMM states store information in the |
| * MXCSR and MXCSR_FLAGS fields of the FP area. That means if the FP |
| * area is marked as unused in the xfeatures header, we need to copy |
| * MXCSR and MXCSR_FLAGS if either SSE or YMM are in use. |
| */ |
| static inline bool xfeatures_mxcsr_quirk(u64 xfeatures) |
| { |
| if (!(xfeatures & (XFEATURE_MASK_SSE|XFEATURE_MASK_YMM))) |
| return false; |
| |
| if (xfeatures & XFEATURE_MASK_FP) |
| return false; |
| |
| return true; |
| } |
| |
| static void fill_gap(unsigned to, void **kbuf, unsigned *pos, unsigned *count) |
| { |
| if (*pos < to) { |
| unsigned size = to - *pos; |
| |
| if (size > *count) |
| size = *count; |
| memcpy(*kbuf, (void *)&init_fpstate.xsave + *pos, size); |
| *kbuf += size; |
| *pos += size; |
| *count -= size; |
| } |
| } |
| |
| static void copy_part(unsigned offset, unsigned size, void *from, |
| void **kbuf, unsigned *pos, unsigned *count) |
| { |
| fill_gap(offset, kbuf, pos, count); |
| if (size > *count) |
| size = *count; |
| if (size) { |
| memcpy(*kbuf, from, size); |
| *kbuf += size; |
| *pos += size; |
| *count -= size; |
| } |
| } |
| |
| /* |
| * Convert from kernel XSAVES compacted format to standard format and copy |
| * to a kernel-space ptrace buffer. |
| * |
| * It supports partial copy but pos always starts from zero. This is called |
| * from xstateregs_get() and there we check the CPU has XSAVES. |
| */ |
| int copy_xstate_to_kernel(void *kbuf, struct xregs_state *xsave, unsigned int offset_start, unsigned int size_total) |
| { |
| struct xstate_header header; |
| const unsigned off_mxcsr = offsetof(struct fxregs_state, mxcsr); |
| unsigned count = size_total; |
| int i; |
| |
| /* |
| * Currently copy_regset_to_user() starts from pos 0: |
| */ |
| if (unlikely(offset_start != 0)) |
| return -EFAULT; |
| |
| /* |
| * The destination is a ptrace buffer; we put in only user xstates: |
| */ |
| memset(&header, 0, sizeof(header)); |
| header.xfeatures = xsave->header.xfeatures; |
| header.xfeatures &= xfeatures_mask_user(); |
| |
| if (header.xfeatures & XFEATURE_MASK_FP) |
| copy_part(0, off_mxcsr, |
| &xsave->i387, &kbuf, &offset_start, &count); |
| if (header.xfeatures & (XFEATURE_MASK_SSE | XFEATURE_MASK_YMM)) |
| copy_part(off_mxcsr, MXCSR_AND_FLAGS_SIZE, |
| &xsave->i387.mxcsr, &kbuf, &offset_start, &count); |
| if (header.xfeatures & XFEATURE_MASK_FP) |
| copy_part(offsetof(struct fxregs_state, st_space), 128, |
| &xsave->i387.st_space, &kbuf, &offset_start, &count); |
| if (header.xfeatures & XFEATURE_MASK_SSE) |
| copy_part(xstate_offsets[XFEATURE_MASK_SSE], 256, |
| &xsave->i387.xmm_space, &kbuf, &offset_start, &count); |
| /* |
| * Fill xsave->i387.sw_reserved value for ptrace frame: |
| */ |
| copy_part(offsetof(struct fxregs_state, sw_reserved), 48, |
| xstate_fx_sw_bytes, &kbuf, &offset_start, &count); |
| /* |
| * Copy xregs_state->header: |
| */ |
| copy_part(offsetof(struct xregs_state, header), sizeof(header), |
| &header, &kbuf, &offset_start, &count); |
| |
| for (i = FIRST_EXTENDED_XFEATURE; i < XFEATURE_MAX; i++) { |
| /* |
| * Copy only in-use xstates: |
| */ |
| if ((header.xfeatures >> i) & 1) { |
| void *src = __raw_xsave_addr(xsave, i); |
| |
| copy_part(xstate_offsets[i], xstate_sizes[i], |
| src, &kbuf, &offset_start, &count); |
| } |
| |
| } |
| fill_gap(size_total, &kbuf, &offset_start, &count); |
| |
| return 0; |
| } |
| |
| static inline int |
| __copy_xstate_to_user(void __user *ubuf, const void *data, unsigned int offset, unsigned int size, unsigned int size_total) |
| { |
| if (!size) |
| return 0; |
| |
| if (offset < size_total) { |
| unsigned int copy = min(size, size_total - offset); |
| |
| if (__copy_to_user(ubuf + offset, data, copy)) |
| return -EFAULT; |
| } |
| return 0; |
| } |
| |
| /* |
| * Convert from kernel XSAVES compacted format to standard format and copy |
| * to a user-space buffer. It supports partial copy but pos always starts from |
| * zero. This is called from xstateregs_get() and there we check the CPU |
| * has XSAVES. |
| */ |
| int copy_xstate_to_user(void __user *ubuf, struct xregs_state *xsave, unsigned int offset_start, unsigned int size_total) |
| { |
| unsigned int offset, size; |
| int ret, i; |
| struct xstate_header header; |
| |
| /* |
| * Currently copy_regset_to_user() starts from pos 0: |
| */ |
| if (unlikely(offset_start != 0)) |
| return -EFAULT; |
| |
| /* |
| * The destination is a ptrace buffer; we put in only user xstates: |
| */ |
| memset(&header, 0, sizeof(header)); |
| header.xfeatures = xsave->header.xfeatures; |
| header.xfeatures &= xfeatures_mask_user(); |
| |
| /* |
| * Copy xregs_state->header: |
| */ |
| offset = offsetof(struct xregs_state, header); |
| size = sizeof(header); |
| |
| ret = __copy_xstate_to_user(ubuf, &header, offset, size, size_total); |
| if (ret) |
| return ret; |
| |
| for (i = 0; i < XFEATURE_MAX; i++) { |
| /* |
| * Copy only in-use xstates: |
| */ |
| if ((header.xfeatures >> i) & 1) { |
| void *src = __raw_xsave_addr(xsave, i); |
| |
| offset = xstate_offsets[i]; |
| size = xstate_sizes[i]; |
| |
| /* The next component has to fit fully into the output buffer: */ |
| if (offset + size > size_total) |
| break; |
| |
| ret = __copy_xstate_to_user(ubuf, src, offset, size, size_total); |
| if (ret) |
| return ret; |
| } |
| |
| } |
| |
| if (xfeatures_mxcsr_quirk(header.xfeatures)) { |
| offset = offsetof(struct fxregs_state, mxcsr); |
| size = MXCSR_AND_FLAGS_SIZE; |
| __copy_xstate_to_user(ubuf, &xsave->i387.mxcsr, offset, size, size_total); |
| } |
| |
| /* |
| * Fill xsave->i387.sw_reserved value for ptrace frame: |
| */ |
| offset = offsetof(struct fxregs_state, sw_reserved); |
| size = sizeof(xstate_fx_sw_bytes); |
| |
| ret = __copy_xstate_to_user(ubuf, xstate_fx_sw_bytes, offset, size, size_total); |
| if (ret) |
| return ret; |
| |
| return 0; |
| } |
| |
| /* |
| * Convert from a ptrace standard-format kernel buffer to kernel XSAVES format |
| * and copy to the target thread. This is called from xstateregs_set(). |
| */ |
| int copy_kernel_to_xstate(struct xregs_state *xsave, const void *kbuf) |
| { |
| unsigned int offset, size; |
| int i; |
| struct xstate_header hdr; |
| |
| offset = offsetof(struct xregs_state, header); |
| size = sizeof(hdr); |
| |
| memcpy(&hdr, kbuf + offset, size); |
| |
| if (validate_user_xstate_header(&hdr)) |
| return -EINVAL; |
| |
| for (i = 0; i < XFEATURE_MAX; i++) { |
| u64 mask = ((u64)1 << i); |
| |
| if (hdr.xfeatures & mask) { |
| void *dst = __raw_xsave_addr(xsave, i); |
| |
| offset = xstate_offsets[i]; |
| size = xstate_sizes[i]; |
| |
| memcpy(dst, kbuf + offset, size); |
| } |
| } |
| |
| if (xfeatures_mxcsr_quirk(hdr.xfeatures)) { |
| offset = offsetof(struct fxregs_state, mxcsr); |
| size = MXCSR_AND_FLAGS_SIZE; |
| memcpy(&xsave->i387.mxcsr, kbuf + offset, size); |
| } |
| |
| /* |
| * The state that came in from userspace was user-state only. |
| * Mask all the user states out of 'xfeatures': |
| */ |
| xsave->header.xfeatures &= XFEATURE_MASK_SUPERVISOR_ALL; |
| |
| /* |
| * Add back in the features that came in from userspace: |
| */ |
| xsave->header.xfeatures |= hdr.xfeatures; |
| |
| return 0; |
| } |
| |
| /* |
| * Convert from a ptrace or sigreturn standard-format user-space buffer to |
| * kernel XSAVES format and copy to the target thread. This is called from |
| * xstateregs_set(), as well as potentially from the sigreturn() and |
| * rt_sigreturn() system calls. |
| */ |
| int copy_user_to_xstate(struct xregs_state *xsave, const void __user *ubuf) |
| { |
| unsigned int offset, size; |
| int i; |
| struct xstate_header hdr; |
| |
| offset = offsetof(struct xregs_state, header); |
| size = sizeof(hdr); |
| |
| if (__copy_from_user(&hdr, ubuf + offset, size)) |
| return -EFAULT; |
| |
| if (validate_user_xstate_header(&hdr)) |
| return -EINVAL; |
| |
| for (i = 0; i < XFEATURE_MAX; i++) { |
| u64 mask = ((u64)1 << i); |
| |
| if (hdr.xfeatures & mask) { |
| void *dst = __raw_xsave_addr(xsave, i); |
| |
| offset = xstate_offsets[i]; |
| size = xstate_sizes[i]; |
| |
| if (__copy_from_user(dst, ubuf + offset, size)) |
| return -EFAULT; |
| } |
| } |
| |
| if (xfeatures_mxcsr_quirk(hdr.xfeatures)) { |
| offset = offsetof(struct fxregs_state, mxcsr); |
| size = MXCSR_AND_FLAGS_SIZE; |
| if (__copy_from_user(&xsave->i387.mxcsr, ubuf + offset, size)) |
| return -EFAULT; |
| } |
| |
| /* |
| * The state that came in from userspace was user-state only. |
| * Mask all the user states out of 'xfeatures': |
| */ |
| xsave->header.xfeatures &= XFEATURE_MASK_SUPERVISOR_ALL; |
| |
| /* |
| * Add back in the features that came in from userspace: |
| */ |
| xsave->header.xfeatures |= hdr.xfeatures; |
| |
| return 0; |
| } |
| |
| /* |
| * Save only supervisor states to the kernel buffer. This blows away all |
| * old states, and is intended to be used only in __fpu__restore_sig(), where |
| * user states are restored from the user buffer. |
| */ |
| void copy_supervisor_to_kernel(struct xregs_state *xstate) |
| { |
| struct xstate_header *header; |
| u64 max_bit, min_bit; |
| u32 lmask, hmask; |
| int err, i; |
| |
| if (WARN_ON(!boot_cpu_has(X86_FEATURE_XSAVES))) |
| return; |
| |
| if (!xfeatures_mask_supervisor()) |
| return; |
| |
| max_bit = __fls(xfeatures_mask_supervisor()); |
| min_bit = __ffs(xfeatures_mask_supervisor()); |
| |
| lmask = xfeatures_mask_supervisor(); |
| hmask = xfeatures_mask_supervisor() >> 32; |
| XSTATE_OP(XSAVES, xstate, lmask, hmask, err); |
| |
| /* We should never fault when copying to a kernel buffer: */ |
| if (WARN_ON_FPU(err)) |
| return; |
| |
| /* |
| * At this point, the buffer has only supervisor states and must be |
| * converted back to normal kernel format. |
| */ |
| header = &xstate->header; |
| header->xcomp_bv |= xfeatures_mask_all; |
| |
| /* |
| * This only moves states up in the buffer. Start with |
| * the last state and move backwards so that states are |
| * not overwritten until after they are moved. Note: |
| * memmove() allows overlapping src/dst buffers. |
| */ |
| for (i = max_bit; i >= min_bit; i--) { |
| u8 *xbuf = (u8 *)xstate; |
| |
| if (!((header->xfeatures >> i) & 1)) |
| continue; |
| |
| /* Move xfeature 'i' into its normal location */ |
| memmove(xbuf + xstate_comp_offsets[i], |
| xbuf + xstate_supervisor_only_offsets[i], |
| xstate_sizes[i]); |
| } |
| } |
| |
| #ifdef CONFIG_PROC_PID_ARCH_STATUS |
| /* |
| * Report the amount of time elapsed in millisecond since last AVX512 |
| * use in the task. |
| */ |
| static void avx512_status(struct seq_file *m, struct task_struct *task) |
| { |
| unsigned long timestamp = READ_ONCE(task->thread.fpu.avx512_timestamp); |
| long delta; |
| |
| if (!timestamp) { |
| /* |
| * Report -1 if no AVX512 usage |
| */ |
| delta = -1; |
| } else { |
| delta = (long)(jiffies - timestamp); |
| /* |
| * Cap to LONG_MAX if time difference > LONG_MAX |
| */ |
| if (delta < 0) |
| delta = LONG_MAX; |
| delta = jiffies_to_msecs(delta); |
| } |
| |
| seq_put_decimal_ll(m, "AVX512_elapsed_ms:\t", delta); |
| seq_putc(m, '\n'); |
| } |
| |
| /* |
| * Report architecture specific information |
| */ |
| int proc_pid_arch_status(struct seq_file *m, struct pid_namespace *ns, |
| struct pid *pid, struct task_struct *task) |
| { |
| /* |
| * Report AVX512 state if the processor and build option supported. |
| */ |
| if (cpu_feature_enabled(X86_FEATURE_AVX512F)) |
| avx512_status(m, task); |
| |
| return 0; |
| } |
| #endif /* CONFIG_PROC_PID_ARCH_STATUS */ |