diff options
| -rw-r--r-- | arch/x86/kernel/fpu/xstate.c | 35 |
1 files changed, 24 insertions, 11 deletions
diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c index 4704955..a8297f2 100644 --- a/arch/x86/kernel/fpu/xstate.c +++ b/arch/x86/kernel/fpu/xstate.c @@ -185,18 +185,41 @@ void fpu__init_cpu_xstate(void) } /* + * 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. */ 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); for (i = FIRST_EXTENDED_XFEATURE; i < XFEATURE_MAX; i++) { - cpuid_count(XSTATE_CPUID, i, &eax, &ebx, &ecx, &edx); + 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", i, ebx, i, eax); } @@ -226,16 +249,6 @@ static void __init print_xstate_features(void) } /* - * 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)); -} - -/* * 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. |