From 8c9e607376968865456b33d9a2efdee2c7e1030d Mon Sep 17 00:00:00 2001 From: Yu-cheng Yu Date: Thu, 12 Dec 2019 13:08:53 -0800 Subject: x86/fpu/xstate: Fix small issues In response to earlier comments, fix small issues before introducing XSAVES supervisor states: - Fix comments of xfeature_is_supervisor(). - Replace ((u64)1 << 63) with XCOMP_BV_COMPACTED_FORMAT. No functional changes. Signed-off-by: Yu-cheng Yu Signed-off-by: Borislav Petkov Reviewed-by: Dave Hansen Reviewed-by: Tony Luck Acked-by: Sebastian Andrzej Siewior Cc: Andy Lutomirski Cc: Dave Hansen Cc: Fenghua Yu Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: Peter Zijlstra Cc: "Ravi V. Shankar" Cc: Rik van Riel Cc: Thomas Gleixner Cc: x86-ml Link: https://lkml.kernel.org/r/20191212210855.19260-2-yu-cheng.yu@intel.com --- arch/x86/kernel/fpu/xstate.c | 12 +++++------- 1 file changed, 5 insertions(+), 7 deletions(-) (limited to 'arch/x86') diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c index fa31470bbf24..4588fc57203e 100644 --- a/arch/x86/kernel/fpu/xstate.c +++ b/arch/x86/kernel/fpu/xstate.c @@ -110,12 +110,9 @@ EXPORT_SYMBOL_GPL(cpu_has_xfeatures); 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. + * 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; @@ -419,7 +416,8 @@ static void __init setup_init_fpu_buf(void) print_xstate_features(); if (boot_cpu_has(X86_FEATURE_XSAVES)) - init_fpstate.xsave.header.xcomp_bv = (u64)1 << 63 | xfeatures_mask; + init_fpstate.xsave.header.xcomp_bv = XCOMP_BV_COMPACTED_FORMAT | + xfeatures_mask; /* * Init all the features state with header.xfeatures being 0x0 -- cgit v1.2.3