*/
u64 xfeatures_mask __read_mostly;
-static unsigned int xstate_offsets[XFEATURES_NR_MAX] = { [ 0 ... XFEATURES_NR_MAX - 1] = -1};
-static unsigned int xstate_sizes[XFEATURES_NR_MAX] = { [ 0 ... XFEATURES_NR_MAX - 1] = -1};
+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[sizeof(xfeatures_mask)*8];
-/* The number of supported xfeatures in xfeatures_mask: */
-static unsigned int xfeatures_nr;
+/*
+ * Clear all of the X86_FEATURE_* bits that are unavailable
+ * when the CPU has no XSAVE support.
+ */
+void fpu__xstate_clear_all_cpu_caps(void)
+{
+ setup_clear_cpu_cap(X86_FEATURE_XSAVE);
+ setup_clear_cpu_cap(X86_FEATURE_XSAVEOPT);
+ setup_clear_cpu_cap(X86_FEATURE_XSAVEC);
+ setup_clear_cpu_cap(X86_FEATURE_XSAVES);
+ setup_clear_cpu_cap(X86_FEATURE_AVX);
+ setup_clear_cpu_cap(X86_FEATURE_AVX2);
+ setup_clear_cpu_cap(X86_FEATURE_AVX512F);
+ setup_clear_cpu_cap(X86_FEATURE_AVX512PF);
+ setup_clear_cpu_cap(X86_FEATURE_AVX512ER);
+ setup_clear_cpu_cap(X86_FEATURE_AVX512CD);
+ setup_clear_cpu_cap(X86_FEATURE_MPX);
+}
/*
* Return whether the system supports a given xfeature.
/*
* 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 "XSTATE_SSE | XSTATE_YMM" we'll print the
+ * asks about "XFEATURE_MASK_SSE | XFEATURE_MASK_YMM" we'll print the
* missing AVX feature - this is the most informative message
* to users:
*/
/*
* FP is in init state
*/
- if (!(xfeatures & XSTATE_FP)) {
+ if (!(xfeatures & XFEATURE_MASK_FP)) {
fx->cwd = 0x37f;
fx->swd = 0;
fx->twd = 0;
/*
* SSE is in init state
*/
- if (!(xfeatures & XSTATE_SSE))
+ if (!(xfeatures & XFEATURE_MASK_SSE))
memset(&fx->xmm_space[0], 0, 256);
/*
xsetbv(XCR_XFEATURE_ENABLED_MASK, xfeatures_mask);
}
+/*
+ * Note that in the future we will likely need a pair of
+ * functions here: one for user xstates and the other for
+ * system xstates. For now, they are the same.
+ */
+static int xfeature_enabled(enum xfeature xfeature)
+{
+ return !!(xfeatures_mask & (1UL << xfeature));
+}
+
/*
* Record the offsets and sizes of various xstates contained
* in the XSAVE state memory layout.
- *
- * ( Note that certain features might be non-present, for them
- * we'll have 0 offset and 0 size. )
*/
static void __init setup_xstate_features(void)
{
- u32 eax, ebx, ecx, edx, leaf;
-
- xfeatures_nr = fls64(xfeatures_mask);
-
- for (leaf = 2; leaf < xfeatures_nr; leaf++) {
- cpuid_count(XSTATE_CPUID, leaf, &eax, &ebx, &ecx, &edx);
-
- xstate_offsets[leaf] = ebx;
- xstate_sizes[leaf] = eax;
+ 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);
+
+ for (i = FIRST_EXTENDED_XFEATURE; i < XFEATURE_MAX; i++) {
+ if (!xfeature_enabled(i))
+ continue;
+
+ cpuid_count(XSTATE_CPUID, i, &eax, &ebx, &ecx, &edx);
+ xstate_offsets[i] = ebx;
+ xstate_sizes[i] = eax;
+ /*
+ * 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];
- printk(KERN_INFO "x86/fpu: xstate_offset[%d]: %4d, xstate_sizes[%d]: %4d\n", leaf, ebx, leaf, eax);
+ printk(KERN_INFO "x86/fpu: xstate_offset[%d]: %4d, xstate_sizes[%d]: %4d\n", i, ebx, i, eax);
}
}
*/
static void __init print_xstate_features(void)
{
- print_xstate_feature(XSTATE_FP);
- print_xstate_feature(XSTATE_SSE);
- print_xstate_feature(XSTATE_YMM);
- print_xstate_feature(XSTATE_BNDREGS);
- print_xstate_feature(XSTATE_BNDCSR);
- print_xstate_feature(XSTATE_OPMASK);
- print_xstate_feature(XSTATE_ZMM_Hi256);
- print_xstate_feature(XSTATE_Hi16_ZMM);
+ 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);
}
/*
xstate_comp_offsets[1] = offsetof(struct fxregs_state, xmm_space);
if (!cpu_has_xsaves) {
- for (i = 2; i < xfeatures_nr; i++) {
- if (test_bit(i, (unsigned long *)&xfeatures_mask)) {
+ for (i = FIRST_EXTENDED_XFEATURE; i < XFEATURE_MAX; i++) {
+ if (xfeature_enabled(i)) {
xstate_comp_offsets[i] = xstate_offsets[i];
xstate_comp_sizes[i] = xstate_sizes[i];
}
return;
}
- xstate_comp_offsets[2] = FXSAVE_SIZE + XSAVE_HDR_SIZE;
+ xstate_comp_offsets[FIRST_EXTENDED_XFEATURE] =
+ FXSAVE_SIZE + XSAVE_HDR_SIZE;
- for (i = 2; i < xfeatures_nr; i++) {
- if (test_bit(i, (unsigned long *)&xfeatures_mask))
+ for (i = FIRST_EXTENDED_XFEATURE; i < XFEATURE_MAX; i++) {
+ if (xfeature_enabled(i))
xstate_comp_sizes[i] = xstate_sizes[i];
else
xstate_comp_sizes[i] = 0;
- if (i > 2)
+ if (i > FIRST_EXTENDED_XFEATURE)
xstate_comp_offsets[i] = xstate_comp_offsets[i-1]
+ xstate_comp_sizes[i-1];
copy_xregs_to_kernel_booting(&init_fpstate.xsave);
}
+static int xfeature_is_supervisor(int xfeature_nr)
+{
+ /*
+ * We currently do not support supervisor states, but if
+ * we did, we could find out like this.
+ *
+ * SDM says: If state component i is a user state component,
+ * ECX[0] return 0; if state component i is a supervisor
+ * state component, ECX[0] returns 1.
+ u32 eax, ebx, ecx, edx;
+ cpuid_count(XSTATE_CPUID, xfeature_nr, &eax, &ebx, &ecx, &edx;
+ return !!(ecx & 1);
+ */
+ return 0;
+}
+/*
+static int xfeature_is_user(int xfeature_nr)
+{
+ return !xfeature_is_supervisor(xfeature_nr);
+}
+*/
+
+/*
+ * 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);
+ 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);
+}
+
+static int xfeature_uncompacted_offset(int xfeature_nr)
+{
+ u32 eax, ebx, ecx, edx;
+
+ 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.
+ */
+static int using_compacted_format(void)
+{
+ return cpu_has_xsaves;
+}
+
+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);
+
+ /*
+ * 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)) {
+ 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 != xstate_size);
+}
+
/*
* Calculate total size of enabled xstates in XCR0/xfeatures_mask.
+ *
+ * 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.
+ *
+ * Note that we do not currently set any bits on IA32_XSS so
+ * 'XCR0 | IA32_XSS == XCR0' for now.
*/
-static void __init init_xstate_size(void)
+static unsigned int __init calculate_xstate_size(void)
{
unsigned int eax, ebx, ecx, edx;
- int i;
+ unsigned int calculated_xstate_size;
if (!cpu_has_xsaves) {
+ /*
+ * - 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);
- xstate_size = ebx;
- return;
+ calculated_xstate_size = ebx;
+ } else {
+ /*
+ * - 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);
+ calculated_xstate_size = ebx;
}
+ return calculated_xstate_size;
+}
- 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;
- }
- }
+/*
+ * 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_xstate_size(void)
+{
+ /* Recompute the context size for enabled features: */
+ unsigned int possible_xstate_size = calculate_xstate_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.
+ */
+ xstate_size = possible_xstate_size;
+ do_extra_xstate_size_checks();
+ 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 = 0;
+ cr4_clear_bits(X86_CR4_OSXSAVE);
+ fpu__xstate_clear_all_cpu_caps();
}
/*
{
unsigned int eax, ebx, ecx, edx;
static int on_boot_cpu = 1;
+ int err;
WARN_ON_FPU(!on_boot_cpu);
on_boot_cpu = 0;
cpuid_count(XSTATE_CPUID, 0, &eax, &ebx, &ecx, &edx);
xfeatures_mask = eax + ((u64)edx << 32);
- if ((xfeatures_mask & XSTATE_FPSSE) != XSTATE_FPSSE) {
+ if ((xfeatures_mask & XFEATURE_MASK_FPSSE) != XFEATURE_MASK_FPSSE) {
pr_err("x86/fpu: FP/SSE not present amongst the CPU's xstate features: 0x%llx.\n", xfeatures_mask);
BUG();
}
/* Enable xstate instructions to be able to continue with initialization: */
fpu__init_cpu_xstate();
-
- /* Recompute the context size for enabled features: */
- init_xstate_size();
+ err = init_xstate_size();
+ if (err) {
+ /* something went wrong, boot without any XSAVE support */
+ fpu__init_disable_system_xstate();
+ return;
+ }
update_regset_xstate_info(xstate_size, xfeatures_mask);
fpu__init_prepare_fx_sw_frame();
* Inputs:
* xstate: the thread's storage area for all FPU data
* xstate_feature: state which is defined in xsave.h (e.g.
- * XSTATE_FP, XSTATE_SSE, etc...)
+ * XFEATURE_MASK_FP, XFEATURE_MASK_SSE, etc...)
* Output:
* address of the state in the xsave area, or NULL if the
* field is not present in the xsave buffer.
* Note that this only works on the current task.
*
* Inputs:
- * @xsave_state: state which is defined in xsave.h (e.g. XSTATE_FP,
- * XSTATE_SSE, etc...)
+ * @xsave_state: state which is defined in xsave.h (e.g. XFEATURE_MASK_FP,
+ * XFEATURE_MASK_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'.
projects / karo-tx-linux.git / blobdiff