diff options
| -rw-r--r-- | arch/x86/kernel/fpu/xstate.c | 28 |
1 files changed, 15 insertions, 13 deletions
diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c index bcb9f5648cfd..a64f61ae8540 100644 --- a/arch/x86/kernel/fpu/xstate.c +++ b/arch/x86/kernel/fpu/xstate.c @@ -59,7 +59,7 @@ static short xsave_cpuid_features[] __initdata = { * 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; +u64 xfeatures_mask_all __ro_after_init; static unsigned int xstate_offsets[XFEATURE_MAX] __ro_after_init = { [ 0 ... XFEATURE_MAX - 1] = -1}; @@ -213,19 +213,8 @@ void fpstate_sanitize_xstate(struct fpu *fpu) */ 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); @@ -825,6 +814,7 @@ void __init fpu__init_system_xstate(void) { unsigned int eax, ebx, ecx, edx; static int on_boot_cpu __initdata = 1; + u64 xfeatures; int err; int i; @@ -879,6 +869,8 @@ void __init fpu__init_system_xstate(void) } xfeatures_mask_all &= fpu__get_supported_xfeatures_mask(); + /* Store it for paranoia check at the end */ + xfeatures = xfeatures_mask_all; /* Enable xstate instructions to be able to continue with initialization: */ fpu__init_cpu_xstate(); @@ -896,8 +888,18 @@ void __init fpu__init_system_xstate(void) setup_init_fpu_buf(); setup_xstate_comp_offsets(); setup_supervisor_only_offsets(); - print_xstate_offset_size(); + /* + * Paranoia check whether something in the setup modified the + * xfeatures mask. + */ + if (xfeatures != xfeatures_mask_all) { + pr_err("x86/fpu: xfeatures modified from 0x%016llx to 0x%016llx during init, disabling XSAVE\n", + xfeatures, xfeatures_mask_all); + goto out_disable; + } + + 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, |