From 03482e08a87d24e5c8c23e6981c482e832cf3bdc Mon Sep 17 00:00:00 2001 From: Yu-cheng Yu Date: Fri, 17 Jun 2016 13:07:15 -0700 Subject: [PATCH] x86/fpu/xstate: Align xstate components according to CPUID CPUID function 0x0d, sub function (i, i > 1) returns in ecx[1] the alignment requirement of component 'i' when the compacted format is used. If ecx[1] is 0, component 'i' is located immediately following the preceding component. If ecx[1] is 1, component 'i' is located on the next 64-byte boundary following the preceding component. Signed-off-by: Yu-cheng Yu Reviewed-by: Dave Hansen Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Dave Hansen Cc: Denys Vlasenko Cc: Fenghua Yu Cc: H. Peter Anvin Cc: Josh Poimboeuf Cc: Linus Torvalds Cc: Oleg Nesterov Cc: Peter Zijlstra Cc: Quentin Casasnovas Cc: Ravi V. Shankar Cc: Sai Praneeth Prakhya Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/331e2bef1a0a7a584f06adde095b6bbfbe166472.1466179491.git.yu-cheng.yu@intel.com Signed-off-by: Ingo Molnar --- arch/x86/kernel/fpu/xstate.c | 60 +++++++++++++++++++----------------- 1 file changed, 32 insertions(+), 28 deletions(-) diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c index 0b01f003df8b..7963029cb4ad 100644 --- a/arch/x86/kernel/fpu/xstate.c +++ b/arch/x86/kernel/fpu/xstate.c @@ -269,6 +269,33 @@ static void __init print_xstate_features(void) 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); + 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 @@ -306,10 +333,14 @@ static void __init setup_xstate_comp(void) else xstate_comp_sizes[i] = 0; - if (i > FIRST_EXTENDED_XFEATURE) + if (i > FIRST_EXTENDED_XFEATURE) { xstate_comp_offsets[i] = xstate_comp_offsets[i-1] + xstate_comp_sizes[i-1]; + if (xfeature_is_aligned(i)) + xstate_comp_offsets[i] = + ALIGN(xstate_comp_offsets[i], 64); + } } } @@ -366,33 +397,6 @@ static int xfeature_is_user(int 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; -- 2.39.5