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 <hpa@zytor.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
H. Peter Anvin
Ingo Molnar
parent
b4a091a62c
commit
6152e4b1c9
@ -552,18 +552,17 @@ static int restore_i387_xsave(void __user *buf)
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(struct i387_fxsave_struct __user *) &fx_user->_fxsr_env[0];
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struct xsave_hdr_struct *xsave_hdr =
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¤t->thread.xstate->xsave.xsave_hdr;
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unsigned int lmask, hmask;
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u64 mask;
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int err;
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if (check_for_xstate(fx, buf, &fx_sw_user))
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goto fx_only;
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lmask = fx_sw_user.xstate_bv;
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hmask = fx_sw_user.xstate_bv >> 32;
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mask = fx_sw_user.xstate_bv;
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err = restore_i387_fxsave(buf, fx_sw_user.xstate_size);
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xsave_hdr->xstate_bv &= (pcntxt_lmask | (((u64) pcntxt_hmask) << 32));
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xsave_hdr->xstate_bv &= pcntxt_mask;
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/*
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* These bits must be zero.
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*/
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@ -573,9 +572,8 @@ static int restore_i387_xsave(void __user *buf)
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* Init the state that is not present in the memory layout
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* and enabled by the OS.
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*/
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lmask = ~(pcntxt_lmask & ~lmask);
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hmask = ~(pcntxt_hmask & ~hmask);
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xsave_hdr->xstate_bv &= (lmask | (((u64) hmask) << 32));
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mask = ~(pcntxt_mask & ~mask);
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xsave_hdr->xstate_bv &= mask;
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return err;
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fx_only:
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@ -9,11 +9,12 @@
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#ifdef CONFIG_IA32_EMULATION
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#include <asm/sigcontext32.h>
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#endif
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#include <asm/xcr.h>
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/*
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* Supported feature mask by the CPU and the kernel.
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*/
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unsigned int pcntxt_hmask, pcntxt_lmask;
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u64 pcntxt_mask;
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struct _fpx_sw_bytes fx_sw_reserved;
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#ifdef CONFIG_IA32_EMULATION
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@ -127,30 +128,28 @@ int save_i387_xstate(void __user *buf)
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int restore_user_xstate(void __user *buf)
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{
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struct _fpx_sw_bytes fx_sw_user;
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unsigned int lmask, hmask;
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u64 mask;
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int err;
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if (((unsigned long)buf % 64) ||
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check_for_xstate(buf, buf, &fx_sw_user))
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goto fx_only;
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lmask = fx_sw_user.xstate_bv;
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hmask = fx_sw_user.xstate_bv >> 32;
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mask = fx_sw_user.xstate_bv;
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/*
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* restore the state passed by the user.
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*/
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err = xrestore_user(buf, lmask, hmask);
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err = xrestore_user(buf, mask);
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if (err)
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return err;
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/*
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* init the state skipped by the user.
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*/
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lmask = pcntxt_lmask & ~lmask;
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hmask = pcntxt_hmask & ~hmask;
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mask = pcntxt_mask & ~mask;
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xrstor_state(init_xstate_buf, lmask, hmask);
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xrstor_state(init_xstate_buf, mask);
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return 0;
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@ -160,8 +159,7 @@ int restore_user_xstate(void __user *buf)
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* memory layout. Restore just the FP/SSE and init all
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* the other extended state.
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*/
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xrstor_state(init_xstate_buf, pcntxt_lmask & ~XSTATE_FPSSE,
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pcntxt_hmask);
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xrstor_state(init_xstate_buf, pcntxt_mask & ~XSTATE_FPSSE);
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return fxrstor_checking((__force struct i387_fxsave_struct *)buf);
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}
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@ -231,8 +229,7 @@ void prepare_fx_sw_frame(void)
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fx_sw_reserved.magic1 = FP_XSTATE_MAGIC1;
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fx_sw_reserved.extended_size = sig_xstate_size;
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fx_sw_reserved.xstate_bv = pcntxt_lmask |
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(((u64) (pcntxt_hmask)) << 32);
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fx_sw_reserved.xstate_bv = pcntxt_mask;
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fx_sw_reserved.xstate_size = xstate_size;
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#ifdef CONFIG_IA32_EMULATION
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memcpy(&fx_sw_reserved_ia32, &fx_sw_reserved,
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@ -263,11 +260,8 @@ void __cpuinit xsave_init(void)
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/*
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* Enable all the features that the HW is capable of
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* and the Linux kernel is aware of.
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*
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* xsetbv();
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*/
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asm volatile(".byte 0x0f,0x01,0xd1" : : "c" (0),
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"a" (pcntxt_lmask), "d" (pcntxt_hmask));
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xsetbv(XCR_XFEATURE_ENABLED_MASK, pcntxt_mask);
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}
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/*
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@ -287,36 +281,31 @@ void __init xsave_cntxt_init(void)
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unsigned int eax, ebx, ecx, edx;
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cpuid_count(0xd, 0, &eax, &ebx, &ecx, &edx);
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pcntxt_mask = eax + ((u64)edx << 32);
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pcntxt_lmask = eax;
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pcntxt_hmask = edx;
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if ((pcntxt_lmask & XSTATE_FPSSE) != XSTATE_FPSSE) {
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printk(KERN_ERR "FP/SSE not shown under xsave features %x\n",
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pcntxt_lmask);
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if ((pcntxt_mask & XSTATE_FPSSE) != XSTATE_FPSSE) {
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printk(KERN_ERR "FP/SSE not shown under xsave features 0x%llx\n",
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pcntxt_mask);
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BUG();
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}
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/*
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* for now OS knows only about FP/SSE
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*/
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pcntxt_lmask = pcntxt_lmask & XCNTXT_LMASK;
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pcntxt_hmask = pcntxt_hmask & XCNTXT_HMASK;
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pcntxt_mask = pcntxt_mask & XCNTXT_MASK;
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xsave_init();
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/*
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* Recompute the context size for enabled features
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*/
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cpuid_count(0xd, 0, &eax, &ebx, &ecx, &edx);
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xstate_size = ebx;
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prepare_fx_sw_frame();
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setup_xstate_init();
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printk(KERN_INFO "xsave/xrstor: enabled xstate_bv 0x%Lx, "
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printk(KERN_INFO "xsave/xrstor: enabled xstate_bv 0x%llx, "
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"cntxt size 0x%x\n",
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(pcntxt_lmask | ((u64) pcntxt_hmask << 32)), xstate_size);
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pcntxt_mask, xstate_size);
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}
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@ -1,6 +1,7 @@
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#ifndef __ASM_X86_XSAVE_H
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#define __ASM_X86_XSAVE_H
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#include <linux/types.h>
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#include <asm/processor.h>
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#include <asm/i387.h>
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@ -14,8 +15,7 @@
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/*
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* These are the features that the OS can handle currently.
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*/
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#define XCNTXT_LMASK (XSTATE_FP | XSTATE_SSE)
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#define XCNTXT_HMASK 0x0
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#define XCNTXT_MASK (XSTATE_FP | XSTATE_SSE)
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#ifdef CONFIG_X86_64
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#define REX_PREFIX "0x48, "
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@ -23,7 +23,8 @@
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#define REX_PREFIX
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#endif
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extern unsigned int xstate_size, pcntxt_hmask, pcntxt_lmask;
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extern unsigned int xstate_size;
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extern u64 pcntxt_mask;
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extern struct xsave_struct *init_xstate_buf;
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extern void xsave_cntxt_init(void);
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@ -73,12 +74,12 @@ static inline int xsave_user(struct xsave_struct __user *buf)
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return err;
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}
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static inline int xrestore_user(struct xsave_struct __user *buf,
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unsigned int lmask,
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unsigned int hmask)
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static inline int xrestore_user(struct xsave_struct __user *buf, u64 mask)
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{
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int err;
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struct xsave_struct *xstate = ((__force struct xsave_struct *)buf);
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u32 lmask = mask;
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u32 hmask = mask >> 32;
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__asm__ __volatile__("1: .byte " REX_PREFIX "0x0f,0xae,0x2f\n"
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"2:\n"
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@ -96,8 +97,11 @@ static inline int xrestore_user(struct xsave_struct __user *buf,
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return err;
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}
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static inline void xrstor_state(struct xsave_struct *fx, int lmask, int hmask)
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static inline void xrstor_state(struct xsave_struct *fx, u64 mask)
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{
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u32 lmask = mask;
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u32 hmask = mask >> 32;
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asm volatile(".byte " REX_PREFIX "0x0f,0xae,0x2f\n\t"
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: : "D" (fx), "m" (*fx), "a" (lmask), "d" (hmask)
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: "memory");
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