forked from luck/tmp_suning_uos_patched
06c8173eb9
Commit:f31a9f7c71("x86/xsaves: Use xsaves/xrstors to save and restore xsave area") introduced alternative instructions for XSAVES/XRSTORS and commit:adb9d526e9("x86/xsaves: Add xsaves and xrstors support for booting time") added support for the XSAVES/XRSTORS instructions at boot time. Unfortunately both failed to properly protect them against faulting: The 'xstate_fault' macro will use the closest label named '1' backward and that ends up in the .altinstr_replacement section rather than in .text. This means that the kernel will never find in the __ex_table the .text address where this instruction might fault, leading to serious problems if userspace manages to trigger the fault. Signed-off-by: Quentin Casasnovas <quentin.casasnovas@oracle.com> Signed-off-by: Jamie Iles <jamie.iles@oracle.com> [ Improved the changelog, fixed some whitespace noise. ] Acked-by: Borislav Petkov <bp@alien8.de> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: <stable@vger.kernel.org> Cc: Allan Xavier <mr.a.xavier@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Thomas Gleixner <tglx@linutronix.de> Fixes:adb9d526e9("x86/xsaves: Add xsaves and xrstors support for booting time") Fixes:f31a9f7c71("x86/xsaves: Use xsaves/xrstors to save and restore xsave area") Signed-off-by: Ingo Molnar <mingo@kernel.org>
258 lines
6.3 KiB
C
258 lines
6.3 KiB
C
#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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#define XSTATE_CPUID 0x0000000d
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#define XSTATE_FP 0x1
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#define XSTATE_SSE 0x2
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#define XSTATE_YMM 0x4
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#define XSTATE_BNDREGS 0x8
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#define XSTATE_BNDCSR 0x10
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#define XSTATE_OPMASK 0x20
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#define XSTATE_ZMM_Hi256 0x40
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#define XSTATE_Hi16_ZMM 0x80
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#define XSTATE_FPSSE (XSTATE_FP | XSTATE_SSE)
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#define XSTATE_AVX512 (XSTATE_OPMASK | XSTATE_ZMM_Hi256 | XSTATE_Hi16_ZMM)
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/* Bit 63 of XCR0 is reserved for future expansion */
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#define XSTATE_EXTEND_MASK (~(XSTATE_FPSSE | (1ULL << 63)))
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#define FXSAVE_SIZE 512
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#define XSAVE_HDR_SIZE 64
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#define XSAVE_HDR_OFFSET FXSAVE_SIZE
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#define XSAVE_YMM_SIZE 256
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#define XSAVE_YMM_OFFSET (XSAVE_HDR_SIZE + XSAVE_HDR_OFFSET)
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/* Supported features which support lazy state saving */
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#define XSTATE_LAZY (XSTATE_FP | XSTATE_SSE | XSTATE_YMM \
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| XSTATE_OPMASK | XSTATE_ZMM_Hi256 | XSTATE_Hi16_ZMM)
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/* Supported features which require eager state saving */
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#define XSTATE_EAGER (XSTATE_BNDREGS | XSTATE_BNDCSR)
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/* All currently supported features */
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#define XCNTXT_MASK (XSTATE_LAZY | XSTATE_EAGER)
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#ifdef CONFIG_X86_64
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#define REX_PREFIX "0x48, "
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#else
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#define REX_PREFIX
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#endif
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extern unsigned int xstate_size;
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extern u64 pcntxt_mask;
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extern u64 xstate_fx_sw_bytes[USER_XSTATE_FX_SW_WORDS];
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extern struct xsave_struct *init_xstate_buf;
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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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/* 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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#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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/*
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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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xstate_fault
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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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xstate_fault
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: "D" (fx), "m" (*fx), "a" (lmask), "d" (hmask)
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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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xstate_fault
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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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xstate_fault
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: "D" (fx), "m" (*fx), "a" (lmask), "d" (hmask)
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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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XSAVEOPT,
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X86_FEATURE_XSAVEOPT,
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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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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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/*
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* Clear the xsave header first, so that reserved fields are
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* initialized to zero.
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*/
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err = __clear_user(&buf->xsave_hdr, sizeof(buf->xsave_hdr));
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if (unlikely(err))
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return -EFAULT;
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__asm__ __volatile__(ASM_STAC "\n"
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"1:"XSAVE"\n"
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"2: " ASM_CLAC "\n"
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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 = 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:"XRSTOR"\n"
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"2: " ASM_CLAC "\n"
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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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void *get_xsave_addr(struct xsave_struct *xsave, int xstate);
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void setup_xstate_comp(void);
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#endif
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