Merge branch 'x86-xsave-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86/xsave changes from Peter Anvin: "This is a patchset to support the XSAVES instruction required to support context switch of supervisor-only features in upcoming silicon. This patchset missed the 3.16 merge window, which is why it is based on 3.15-rc7" * 'x86-xsave-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86, xsave: Add forgotten inline annotation x86/xsaves: Clean up code in xstate offsets computation in xsave area x86/xsave: Make it clear that the XSAVE macros use (%edi)/(%rdi) Define kernel API to get address of each state in xsave area x86/xsaves: Enable xsaves/xrstors x86/xsaves: Call booting time xsaves and xrstors in setup_init_fpu_buf x86/xsaves: Save xstate to task's xsave area in __save_fpu during booting time x86/xsaves: Add xsaves and xrstors support for booting time x86/xsaves: Clear reserved bits in xsave header x86/xsaves: Use xsave/xrstor for saving and restoring user space context x86/xsaves: Use xsaves/xrstors for context switch x86/xsaves: Use xsaves/xrstors to save and restore xsave area x86/xsaves: Define a macro for handling xsave/xrstor instruction fault x86/xsaves: Define macros for xsave instructions x86/xsaves: Change compacted format xsave area header x86/alternative: Add alternative_input_2 to support alternative with two features and input x86/xsaves: Add a kernel parameter noxsaves to disable xsaves/xrstors
This commit is contained in:
Linus Torvalds
commit
7453f33b2e
9 changed files with 325 additions and 71 deletions
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@ -2200,6 +2200,21 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
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and restore using xsave. The kernel will fallback to
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enabling legacy floating-point and sse state.
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noxsaveopt [X86] Disables xsaveopt used in saving x86 extended
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register states. The kernel will fall back to use
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xsave to save the states. By using this parameter,
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performance of saving the states is degraded because
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xsave doesn't support modified optimization while
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xsaveopt supports it on xsaveopt enabled systems.
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noxsaves [X86] Disables xsaves and xrstors used in saving and
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restoring x86 extended register state in compacted
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form of xsave area. The kernel will fall back to use
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xsaveopt and xrstor to save and restore the states
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in standard form of xsave area. By using this
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parameter, xsave area per process might occupy more
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memory on xsaves enabled systems.
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eagerfpu= [X86]
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on enable eager fpu restore
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off disable eager fpu restore
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@ -161,6 +161,20 @@ static inline int alternatives_text_reserved(void *start, void *end)
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asm volatile (ALTERNATIVE(oldinstr, newinstr, feature) \
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: : "i" (0), ## input)
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/*
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* This is similar to alternative_input. But it has two features and
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* respective instructions.
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*
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* If CPU has feature2, newinstr2 is used.
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* Otherwise, if CPU has feature1, newinstr1 is used.
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* Otherwise, oldinstr is used.
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*/
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#define alternative_input_2(oldinstr, newinstr1, feature1, newinstr2, \
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feature2, input...) \
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asm volatile(ALTERNATIVE_2(oldinstr, newinstr1, feature1, \
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newinstr2, feature2) \
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: : "i" (0), ## input)
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/* Like alternative_input, but with a single output argument */
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#define alternative_io(oldinstr, newinstr, feature, output, input...) \
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asm volatile (ALTERNATIVE(oldinstr, newinstr, feature) \
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@ -508,9 +508,12 @@ static inline void user_fpu_begin(void)
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static inline void __save_fpu(struct task_struct *tsk)
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{
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if (use_xsave())
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xsave_state(&tsk->thread.fpu.state->xsave, -1);
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if (use_xsave()) {
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if (unlikely(system_state == SYSTEM_BOOTING))
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xsave_state_booting(&tsk->thread.fpu.state->xsave, -1);
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else
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xsave_state(&tsk->thread.fpu.state->xsave, -1);
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} else
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fpu_fxsave(&tsk->thread.fpu);
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}
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@ -385,8 +385,8 @@ struct bndcsr_struct {
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struct xsave_hdr_struct {
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u64 xstate_bv;
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u64 reserved1[2];
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u64 reserved2[5];
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u64 xcomp_bv;
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u64 reserved[6];
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} __attribute__((packed));
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struct xsave_struct {
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@ -52,24 +52,170 @@ extern void xsave_init(void);
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extern void update_regset_xstate_info(unsigned int size, u64 xstate_mask);
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extern int init_fpu(struct task_struct *child);
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static inline int fpu_xrstor_checking(struct xsave_struct *fx)
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{
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int err;
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/* These macros all use (%edi)/(%rdi) as the single memory argument. */
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#define XSAVE ".byte " REX_PREFIX "0x0f,0xae,0x27"
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#define XSAVEOPT ".byte " REX_PREFIX "0x0f,0xae,0x37"
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#define XSAVES ".byte " REX_PREFIX "0x0f,0xc7,0x2f"
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#define XRSTOR ".byte " REX_PREFIX "0x0f,0xae,0x2f"
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#define XRSTORS ".byte " REX_PREFIX "0x0f,0xc7,0x1f"
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asm volatile("1: .byte " REX_PREFIX "0x0f,0xae,0x2f\n\t"
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"2:\n"
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".section .fixup,\"ax\"\n"
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"3: movl $-1,%[err]\n"
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" jmp 2b\n"
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".previous\n"
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_ASM_EXTABLE(1b, 3b)
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#define xstate_fault ".section .fixup,\"ax\"\n" \
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"3: movl $-1,%[err]\n" \
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" jmp 2b\n" \
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".previous\n" \
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_ASM_EXTABLE(1b, 3b) \
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: [err] "=r" (err)
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: "D" (fx), "m" (*fx), "a" (-1), "d" (-1), "0" (0)
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/*
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* This function is called only during boot time when x86 caps are not set
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* up and alternative can not be used yet.
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*/
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static inline int xsave_state_booting(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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int err = 0;
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WARN_ON(system_state != SYSTEM_BOOTING);
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if (boot_cpu_has(X86_FEATURE_XSAVES))
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asm volatile("1:"XSAVES"\n\t"
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"2:\n\t"
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: : "D" (fx), "m" (*fx), "a" (lmask), "d" (hmask)
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: "memory");
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else
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asm volatile("1:"XSAVE"\n\t"
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"2:\n\t"
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: : "D" (fx), "m" (*fx), "a" (lmask), "d" (hmask)
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: "memory");
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asm volatile(xstate_fault
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: "0" (0)
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: "memory");
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return err;
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}
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/*
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* This function is called only during boot time when x86 caps are not set
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* up and alternative can not be used yet.
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*/
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static inline int xrstor_state_booting(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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int err = 0;
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WARN_ON(system_state != SYSTEM_BOOTING);
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if (boot_cpu_has(X86_FEATURE_XSAVES))
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asm volatile("1:"XRSTORS"\n\t"
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"2:\n\t"
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: : "D" (fx), "m" (*fx), "a" (lmask), "d" (hmask)
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: "memory");
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else
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asm volatile("1:"XRSTOR"\n\t"
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"2:\n\t"
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: : "D" (fx), "m" (*fx), "a" (lmask), "d" (hmask)
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: "memory");
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asm volatile(xstate_fault
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: "0" (0)
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: "memory");
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return err;
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}
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/*
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* Save processor xstate to xsave area.
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*/
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static inline int xsave_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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int err = 0;
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/*
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* If xsaves is enabled, xsaves replaces xsaveopt because
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* it supports compact format and supervisor states in addition to
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* modified optimization in xsaveopt.
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*
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* Otherwise, if xsaveopt is enabled, xsaveopt replaces xsave
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* because xsaveopt supports modified optimization which is not
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* supported by xsave.
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*
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* If none of xsaves and xsaveopt is enabled, use xsave.
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*/
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alternative_input_2(
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"1:"XSAVE,
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"1:"XSAVEOPT,
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X86_FEATURE_XSAVEOPT,
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"1:"XSAVES,
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X86_FEATURE_XSAVES,
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[fx] "D" (fx), "a" (lmask), "d" (hmask) :
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"memory");
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asm volatile("2:\n\t"
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xstate_fault
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: "0" (0)
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: "memory");
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return err;
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}
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/*
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* Restore processor xstate from xsave area.
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*/
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static inline int xrstor_state(struct xsave_struct *fx, u64 mask)
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{
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int err = 0;
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u32 lmask = mask;
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u32 hmask = mask >> 32;
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/*
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* Use xrstors to restore context if it is enabled. xrstors supports
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* compacted format of xsave area which is not supported by xrstor.
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*/
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alternative_input(
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"1: " XRSTOR,
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"1: " XRSTORS,
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X86_FEATURE_XSAVES,
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"D" (fx), "m" (*fx), "a" (lmask), "d" (hmask)
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: "memory");
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asm volatile("2:\n"
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xstate_fault
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: "0" (0)
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: "memory");
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return err;
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}
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/*
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* Save xstate context for old process during context switch.
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*/
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static inline void fpu_xsave(struct fpu *fpu)
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{
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xsave_state(&fpu->state->xsave, -1);
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}
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/*
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* Restore xstate context for new process during context switch.
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*/
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static inline int fpu_xrstor_checking(struct xsave_struct *fx)
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{
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return xrstor_state(fx, -1);
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}
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/*
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* Save xstate to user space xsave area.
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*
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* We don't use modified optimization because xrstor/xrstors might track
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* a different application.
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*
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* We don't use compacted format xsave area for
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* backward compatibility for old applications which don't understand
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* compacted format of xsave area.
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*/
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static inline int xsave_user(struct xsave_struct __user *buf)
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{
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int err;
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@ -83,69 +229,34 @@ static inline int xsave_user(struct xsave_struct __user *buf)
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return -EFAULT;
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__asm__ __volatile__(ASM_STAC "\n"
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"1: .byte " REX_PREFIX "0x0f,0xae,0x27\n"
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"1:"XSAVE"\n"
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"2: " ASM_CLAC "\n"
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".section .fixup,\"ax\"\n"
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"3: movl $-1,%[err]\n"
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" jmp 2b\n"
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".previous\n"
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_ASM_EXTABLE(1b,3b)
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: [err] "=r" (err)
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xstate_fault
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: "D" (buf), "a" (-1), "d" (-1), "0" (0)
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: "memory");
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return err;
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}
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/*
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* Restore xstate from user space xsave area.
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*/
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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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int err = 0;
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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__(ASM_STAC "\n"
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"1: .byte " REX_PREFIX "0x0f,0xae,0x2f\n"
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"1:"XRSTOR"\n"
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"2: " ASM_CLAC "\n"
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".section .fixup,\"ax\"\n"
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"3: movl $-1,%[err]\n"
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" jmp 2b\n"
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".previous\n"
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_ASM_EXTABLE(1b,3b)
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: [err] "=r" (err)
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xstate_fault
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: "D" (xstate), "a" (lmask), "d" (hmask), "0" (0)
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: "memory"); /* memory required? */
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return err;
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}
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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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void *get_xsave_addr(struct xsave_struct *xsave, int xstate);
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void setup_xstate_comp(void);
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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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}
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static inline void xsave_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,0x27\n\t"
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: : "D" (fx), "m" (*fx), "a" (lmask), "d" (hmask)
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: "memory");
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}
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static inline void fpu_xsave(struct fpu *fpu)
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{
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/* This, however, we can work around by forcing the compiler to select
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an addressing mode that doesn't require extended registers. */
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alternative_input(
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".byte " REX_PREFIX "0x0f,0xae,0x27",
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".byte " REX_PREFIX "0x0f,0xae,0x37",
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X86_FEATURE_XSAVEOPT,
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[fx] "D" (&fpu->state->xsave), "a" (-1), "d" (-1) :
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"memory");
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}
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#endif
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|
|
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@ -148,6 +148,7 @@ static int __init x86_xsave_setup(char *s)
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{
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setup_clear_cpu_cap(X86_FEATURE_XSAVE);
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setup_clear_cpu_cap(X86_FEATURE_XSAVEOPT);
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setup_clear_cpu_cap(X86_FEATURE_XSAVES);
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setup_clear_cpu_cap(X86_FEATURE_AVX);
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setup_clear_cpu_cap(X86_FEATURE_AVX2);
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return 1;
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|
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@ -161,6 +162,13 @@ static int __init x86_xsaveopt_setup(char *s)
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}
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__setup("noxsaveopt", x86_xsaveopt_setup);
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static int __init x86_xsaves_setup(char *s)
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{
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setup_clear_cpu_cap(X86_FEATURE_XSAVES);
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return 1;
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}
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__setup("noxsaves", x86_xsaves_setup);
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#ifdef CONFIG_X86_32
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static int cachesize_override = -1;
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static int disable_x86_serial_nr = 1;
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|
|
|
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|
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@ -375,7 +375,7 @@ int xstateregs_set(struct task_struct *target, const struct user_regset *regset,
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/*
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* These bits must be zero.
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*/
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xsave_hdr->reserved1[0] = xsave_hdr->reserved1[1] = 0;
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memset(xsave_hdr->reserved, 0, 48);
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return ret;
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}
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|
|
|
|||
|
|
@ -93,6 +93,7 @@ void arch_task_cache_init(void)
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kmem_cache_create("task_xstate", xstate_size,
|
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__alignof__(union thread_xstate),
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SLAB_PANIC | SLAB_NOTRACK, NULL);
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setup_xstate_comp();
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}
|
||||
|
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/*
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||||
|
|
|
|||
|
|
@ -8,6 +8,7 @@
|
|||
|
||||
#include <linux/bootmem.h>
|
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#include <linux/compat.h>
|
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#include <linux/cpu.h>
|
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#include <asm/i387.h>
|
||||
#include <asm/fpu-internal.h>
|
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#include <asm/sigframe.h>
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||||
|
|
@ -24,7 +25,9 @@ u64 pcntxt_mask;
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|||
struct xsave_struct *init_xstate_buf;
|
||||
|
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static struct _fpx_sw_bytes fx_sw_reserved, fx_sw_reserved_ia32;
|
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static unsigned int *xstate_offsets, *xstate_sizes, xstate_features;
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static unsigned int *xstate_offsets, *xstate_sizes;
|
||||
static unsigned int xstate_comp_offsets[sizeof(pcntxt_mask)*8];
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||||
static unsigned int xstate_features;
|
||||
|
||||
/*
|
||||
* If a processor implementation discern that a processor state component is
|
||||
|
|
@ -283,7 +286,7 @@ sanitize_restored_xstate(struct task_struct *tsk,
|
|||
|
||||
if (use_xsave()) {
|
||||
/* These bits must be zero. */
|
||||
xsave_hdr->reserved1[0] = xsave_hdr->reserved1[1] = 0;
|
||||
memset(xsave_hdr->reserved, 0, 48);
|
||||
|
||||
/*
|
||||
* Init the state that is not present in the memory
|
||||
|
|
@ -478,6 +481,52 @@ static void __init setup_xstate_features(void)
|
|||
} while (1);
|
||||
}
|
||||
|
||||
/*
|
||||
* This function sets up offsets and sizes of all extended states in
|
||||
* xsave area. This supports both standard format and compacted format
|
||||
* of the xsave aread.
|
||||
*
|
||||
* Input: void
|
||||
* Output: void
|
||||
*/
|
||||
void setup_xstate_comp(void)
|
||||
{
|
||||
unsigned int xstate_comp_sizes[sizeof(pcntxt_mask)*8];
|
||||
int i;
|
||||
|
||||
/*
|
||||
* The FP xstates and SSE xstates are legacy states. They are always
|
||||
* in the fixed offsets in the xsave area in either compacted form
|
||||
* or standard form.
|
||||
*/
|
||||
xstate_comp_offsets[0] = 0;
|
||||
xstate_comp_offsets[1] = offsetof(struct i387_fxsave_struct, xmm_space);
|
||||
|
||||
if (!cpu_has_xsaves) {
|
||||
for (i = 2; i < xstate_features; i++) {
|
||||
if (test_bit(i, (unsigned long *)&pcntxt_mask)) {
|
||||
xstate_comp_offsets[i] = xstate_offsets[i];
|
||||
xstate_comp_sizes[i] = xstate_sizes[i];
|
||||
}
|
||||
}
|
||||
return;
|
||||
}
|
||||
|
||||
xstate_comp_offsets[2] = FXSAVE_SIZE + XSAVE_HDR_SIZE;
|
||||
|
||||
for (i = 2; i < xstate_features; i++) {
|
||||
if (test_bit(i, (unsigned long *)&pcntxt_mask))
|
||||
xstate_comp_sizes[i] = xstate_sizes[i];
|
||||
else
|
||||
xstate_comp_sizes[i] = 0;
|
||||
|
||||
if (i > 2)
|
||||
xstate_comp_offsets[i] = xstate_comp_offsets[i-1]
|
||||
+ xstate_comp_sizes[i-1];
|
||||
|
||||
}
|
||||
}
|
||||
|
||||
/*
|
||||
* setup the xstate image representing the init state
|
||||
*/
|
||||
|
|
@ -496,15 +545,21 @@ static void __init setup_init_fpu_buf(void)
|
|||
|
||||
setup_xstate_features();
|
||||
|
||||
if (cpu_has_xsaves) {
|
||||
init_xstate_buf->xsave_hdr.xcomp_bv =
|
||||
(u64)1 << 63 | pcntxt_mask;
|
||||
init_xstate_buf->xsave_hdr.xstate_bv = pcntxt_mask;
|
||||
}
|
||||
|
||||
/*
|
||||
* Init all the features state with header_bv being 0x0
|
||||
*/
|
||||
xrstor_state(init_xstate_buf, -1);
|
||||
xrstor_state_booting(init_xstate_buf, -1);
|
||||
/*
|
||||
* Dump the init state again. This is to identify the init state
|
||||
* of any feature which is not represented by all zero's.
|
||||
*/
|
||||
xsave_state(init_xstate_buf, -1);
|
||||
xsave_state_booting(init_xstate_buf, -1);
|
||||
}
|
||||
|
||||
static enum { AUTO, ENABLE, DISABLE } eagerfpu = AUTO;
|
||||
|
|
@ -520,6 +575,30 @@ static int __init eager_fpu_setup(char *s)
|
|||
}
|
||||
__setup("eagerfpu=", eager_fpu_setup);
|
||||
|
||||
|
||||
/*
|
||||
* Calculate total size of enabled xstates in XCR0/pcntxt_mask.
|
||||
*/
|
||||
static void __init init_xstate_size(void)
|
||||
{
|
||||
unsigned int eax, ebx, ecx, edx;
|
||||
int i;
|
||||
|
||||
if (!cpu_has_xsaves) {
|
||||
cpuid_count(XSTATE_CPUID, 0, &eax, &ebx, &ecx, &edx);
|
||||
xstate_size = ebx;
|
||||
return;
|
||||
}
|
||||
|
||||
xstate_size = FXSAVE_SIZE + XSAVE_HDR_SIZE;
|
||||
for (i = 2; i < 64; i++) {
|
||||
if (test_bit(i, (unsigned long *)&pcntxt_mask)) {
|
||||
cpuid_count(XSTATE_CPUID, i, &eax, &ebx, &ecx, &edx);
|
||||
xstate_size += eax;
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
/*
|
||||
* Enable and initialize the xsave feature.
|
||||
*/
|
||||
|
|
@ -551,8 +630,7 @@ static void __init xstate_enable_boot_cpu(void)
|
|||
/*
|
||||
* Recompute the context size for enabled features
|
||||
*/
|
||||
cpuid_count(XSTATE_CPUID, 0, &eax, &ebx, &ecx, &edx);
|
||||
xstate_size = ebx;
|
||||
init_xstate_size();
|
||||
|
||||
update_regset_xstate_info(xstate_size, pcntxt_mask);
|
||||
prepare_fx_sw_frame();
|
||||
|
|
@ -572,8 +650,9 @@ static void __init xstate_enable_boot_cpu(void)
|
|||
}
|
||||
}
|
||||
|
||||
pr_info("enabled xstate_bv 0x%llx, cntxt size 0x%x\n",
|
||||
pcntxt_mask, xstate_size);
|
||||
pr_info("enabled xstate_bv 0x%llx, cntxt size 0x%x using %s\n",
|
||||
pcntxt_mask, xstate_size,
|
||||
cpu_has_xsaves ? "compacted form" : "standard form");
|
||||
}
|
||||
|
||||
/*
|
||||
|
|
@ -635,3 +714,26 @@ void eager_fpu_init(void)
|
|||
else
|
||||
fxrstor_checking(&init_xstate_buf->i387);
|
||||
}
|
||||
|
||||
/*
|
||||
* Given the xsave area and a state inside, this function returns the
|
||||
* address of the state.
|
||||
*
|
||||
* This is the API that is called to get xstate address in either
|
||||
* standard format or compacted format of xsave area.
|
||||
*
|
||||
* Inputs:
|
||||
* xsave: base address of the xsave area;
|
||||
* xstate: state which is defined in xsave.h (e.g. XSTATE_FP, XSTATE_SSE,
|
||||
* etc.)
|
||||
* Output:
|
||||
* address of the state in the xsave area.
|
||||
*/
|
||||
void *get_xsave_addr(struct xsave_struct *xsave, int xstate)
|
||||
{
|
||||
int feature = fls64(xstate) - 1;
|
||||
if (!test_bit(feature, (unsigned long *)&pcntxt_mask))
|
||||
return NULL;
|
||||
|
||||
return (void *)xsave + xstate_comp_offsets[feature];
|
||||
}
|
||||
|
|
|
|||
Loading…
Add table
Add a link
Reference in a new issue