From 6152e4b1c99a3689fc318d092cd144597f7dbd14 Mon Sep 17 00:00:00 2001 From: "H. Peter Anvin" Date: Tue, 29 Jul 2008 17:23:16 -0700 Subject: [PATCH] x86, xsave: keep the XSAVE feature mask as an u64 The XSAVE feature mask is a 64-bit number; keep it that way, in order to avoid the mistake done with rdmsr/wrmsr. Use the xsetbv() function provided in the previous patch. Signed-off-by: H. Peter Anvin Signed-off-by: Ingo Molnar --- arch/x86/kernel/i387.c | 12 +++++------ arch/x86/kernel/xsave.c | 45 ++++++++++++++++------------------------- include/asm-x86/xsave.h | 18 ++++++++++------- 3 files changed, 33 insertions(+), 42 deletions(-) diff --git a/arch/x86/kernel/i387.c b/arch/x86/kernel/i387.c index e0ed59f5c19..45723f1fe19 100644 --- a/arch/x86/kernel/i387.c +++ b/arch/x86/kernel/i387.c @@ -552,18 +552,17 @@ static int restore_i387_xsave(void __user *buf) (struct i387_fxsave_struct __user *) &fx_user->_fxsr_env[0]; struct xsave_hdr_struct *xsave_hdr = ¤t->thread.xstate->xsave.xsave_hdr; - unsigned int lmask, hmask; + u64 mask; int err; if (check_for_xstate(fx, buf, &fx_sw_user)) goto fx_only; - lmask = fx_sw_user.xstate_bv; - hmask = fx_sw_user.xstate_bv >> 32; + mask = fx_sw_user.xstate_bv; err = restore_i387_fxsave(buf, fx_sw_user.xstate_size); - xsave_hdr->xstate_bv &= (pcntxt_lmask | (((u64) pcntxt_hmask) << 32)); + xsave_hdr->xstate_bv &= pcntxt_mask; /* * These bits must be zero. */ @@ -573,9 +572,8 @@ static int restore_i387_xsave(void __user *buf) * Init the state that is not present in the memory layout * and enabled by the OS. */ - lmask = ~(pcntxt_lmask & ~lmask); - hmask = ~(pcntxt_hmask & ~hmask); - xsave_hdr->xstate_bv &= (lmask | (((u64) hmask) << 32)); + mask = ~(pcntxt_mask & ~mask); + xsave_hdr->xstate_bv &= mask; return err; fx_only: diff --git a/arch/x86/kernel/xsave.c b/arch/x86/kernel/xsave.c index dd66d0714c1..7415f3e38a5 100644 --- a/arch/x86/kernel/xsave.c +++ b/arch/x86/kernel/xsave.c @@ -9,11 +9,12 @@ #ifdef CONFIG_IA32_EMULATION #include #endif +#include /* * Supported feature mask by the CPU and the kernel. */ -unsigned int pcntxt_hmask, pcntxt_lmask; +u64 pcntxt_mask; struct _fpx_sw_bytes fx_sw_reserved; #ifdef CONFIG_IA32_EMULATION @@ -127,30 +128,28 @@ int save_i387_xstate(void __user *buf) int restore_user_xstate(void __user *buf) { struct _fpx_sw_bytes fx_sw_user; - unsigned int lmask, hmask; + u64 mask; int err; if (((unsigned long)buf % 64) || check_for_xstate(buf, buf, &fx_sw_user)) goto fx_only; - lmask = fx_sw_user.xstate_bv; - hmask = fx_sw_user.xstate_bv >> 32; + mask = fx_sw_user.xstate_bv; /* * restore the state passed by the user. */ - err = xrestore_user(buf, lmask, hmask); + err = xrestore_user(buf, mask); if (err) return err; /* * init the state skipped by the user. */ - lmask = pcntxt_lmask & ~lmask; - hmask = pcntxt_hmask & ~hmask; + mask = pcntxt_mask & ~mask; - xrstor_state(init_xstate_buf, lmask, hmask); + xrstor_state(init_xstate_buf, mask); return 0; @@ -160,8 +159,7 @@ fx_only: * memory layout. Restore just the FP/SSE and init all * the other extended state. */ - xrstor_state(init_xstate_buf, pcntxt_lmask & ~XSTATE_FPSSE, - pcntxt_hmask); + xrstor_state(init_xstate_buf, pcntxt_mask & ~XSTATE_FPSSE); return fxrstor_checking((__force struct i387_fxsave_struct *)buf); } @@ -231,8 +229,7 @@ void prepare_fx_sw_frame(void) fx_sw_reserved.magic1 = FP_XSTATE_MAGIC1; fx_sw_reserved.extended_size = sig_xstate_size; - fx_sw_reserved.xstate_bv = pcntxt_lmask | - (((u64) (pcntxt_hmask)) << 32); + fx_sw_reserved.xstate_bv = pcntxt_mask; fx_sw_reserved.xstate_size = xstate_size; #ifdef CONFIG_IA32_EMULATION memcpy(&fx_sw_reserved_ia32, &fx_sw_reserved, @@ -263,11 +260,8 @@ void __cpuinit xsave_init(void) /* * Enable all the features that the HW is capable of * and the Linux kernel is aware of. - * - * xsetbv(); */ - asm volatile(".byte 0x0f,0x01,0xd1" : : "c" (0), - "a" (pcntxt_lmask), "d" (pcntxt_hmask)); + xsetbv(XCR_XFEATURE_ENABLED_MASK, pcntxt_mask); } /* @@ -287,36 +281,31 @@ void __init xsave_cntxt_init(void) unsigned int eax, ebx, ecx, edx; cpuid_count(0xd, 0, &eax, &ebx, &ecx, &edx); + pcntxt_mask = eax + ((u64)edx << 32); - pcntxt_lmask = eax; - pcntxt_hmask = edx; - - if ((pcntxt_lmask & XSTATE_FPSSE) != XSTATE_FPSSE) { - printk(KERN_ERR "FP/SSE not shown under xsave features %x\n", - pcntxt_lmask); + if ((pcntxt_mask & XSTATE_FPSSE) != XSTATE_FPSSE) { + printk(KERN_ERR "FP/SSE not shown under xsave features 0x%llx\n", + pcntxt_mask); BUG(); } /* * for now OS knows only about FP/SSE */ - pcntxt_lmask = pcntxt_lmask & XCNTXT_LMASK; - pcntxt_hmask = pcntxt_hmask & XCNTXT_HMASK; - + pcntxt_mask = pcntxt_mask & XCNTXT_MASK; xsave_init(); /* * Recompute the context size for enabled features */ cpuid_count(0xd, 0, &eax, &ebx, &ecx, &edx); - xstate_size = ebx; prepare_fx_sw_frame(); setup_xstate_init(); - printk(KERN_INFO "xsave/xrstor: enabled xstate_bv 0x%Lx, " + printk(KERN_INFO "xsave/xrstor: enabled xstate_bv 0x%llx, " "cntxt size 0x%x\n", - (pcntxt_lmask | ((u64) pcntxt_hmask << 32)), xstate_size); + pcntxt_mask, xstate_size); } diff --git a/include/asm-x86/xsave.h b/include/asm-x86/xsave.h index b7f64b9fcd9..08e9a1ac07a 100644 --- a/include/asm-x86/xsave.h +++ b/include/asm-x86/xsave.h @@ -1,6 +1,7 @@ #ifndef __ASM_X86_XSAVE_H #define __ASM_X86_XSAVE_H +#include #include #include @@ -14,8 +15,7 @@ /* * These are the features that the OS can handle currently. */ -#define XCNTXT_LMASK (XSTATE_FP | XSTATE_SSE) -#define XCNTXT_HMASK 0x0 +#define XCNTXT_MASK (XSTATE_FP | XSTATE_SSE) #ifdef CONFIG_X86_64 #define REX_PREFIX "0x48, " @@ -23,7 +23,8 @@ #define REX_PREFIX #endif -extern unsigned int xstate_size, pcntxt_hmask, pcntxt_lmask; +extern unsigned int xstate_size; +extern u64 pcntxt_mask; extern struct xsave_struct *init_xstate_buf; extern void xsave_cntxt_init(void); @@ -73,12 +74,12 @@ static inline int xsave_user(struct xsave_struct __user *buf) return err; } -static inline int xrestore_user(struct xsave_struct __user *buf, - unsigned int lmask, - unsigned int hmask) +static inline int xrestore_user(struct xsave_struct __user *buf, u64 mask) { int err; struct xsave_struct *xstate = ((__force struct xsave_struct *)buf); + u32 lmask = mask; + u32 hmask = mask >> 32; __asm__ __volatile__("1: .byte " REX_PREFIX "0x0f,0xae,0x2f\n" "2:\n" @@ -96,8 +97,11 @@ static inline int xrestore_user(struct xsave_struct __user *buf, return err; } -static inline void xrstor_state(struct xsave_struct *fx, int lmask, int hmask) +static inline void xrstor_state(struct xsave_struct *fx, u64 mask) { + u32 lmask = mask; + u32 hmask = mask >> 32; + asm volatile(".byte " REX_PREFIX "0x0f,0xae,0x2f\n\t" : : "D" (fx), "m" (*fx), "a" (lmask), "d" (hmask) : "memory"); -- 2.41.0