x86/fpu: Get rid of xstate_fault()
Add macros for the alternative XSAVE*/XRSTOR* operations which contain the fault handling and use them. Kill xstate_fault(). Also, copy_xregs_to_kernel() didn't have the extended state as memory reference in the asm. Signed-off-by: Borislav Petkov <bp@suse.de> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com> Cc: Rik van Riel <riel@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1447932326-4371-3-git-send-email-bp@alien8.de Signed-off-by: Ingo Molnar <mingo@kernel.org>hifive-unleashed-5.1
Borislav Petkov
Ingo Molnar
parent
b74a0cf1b3
commit
b7106fa0f2
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@ -224,19 +224,6 @@ static inline void copy_fxregs_to_kernel(struct fpu *fpu)
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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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/* xstate instruction fault handler: */
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#define xstate_fault(__err) \
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\
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".section .fixup,\"ax\"\n" \
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\
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"3: movl $-2,%[_err]\n" \
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" jmp 2b\n" \
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\
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".previous\n" \
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\
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_ASM_EXTABLE(1b, 3b) \
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: [_err] "=r" (__err)
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#define XSTATE_OP(op, st, lmask, hmask, err) \
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asm volatile("1:" op "\n\t" \
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"xor %[err], %[err]\n" \
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@ -250,6 +237,54 @@ static inline void copy_fxregs_to_kernel(struct fpu *fpu)
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: "D" (st), "m" (*st), "a" (lmask), "d" (hmask) \
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: "memory")
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/*
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* If XSAVES is enabled, it replaces XSAVEOPT because it supports a compact
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* format and supervisor states in addition to modified optimization in
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* XSAVEOPT.
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*
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* Otherwise, if XSAVEOPT is enabled, XSAVEOPT replaces XSAVE because XSAVEOPT
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* supports modified optimization which is not supported by XSAVE.
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*
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* We use XSAVE as a fallback.
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*
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* The 661 label is defined in the ALTERNATIVE* macros as the address of the
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* original instruction which gets replaced. We need to use it here as the
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* address of the instruction where we might get an exception at.
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*/
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#define XSTATE_XSAVE(st, lmask, hmask, err) \
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asm volatile(ALTERNATIVE_2(XSAVE, \
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XSAVEOPT, X86_FEATURE_XSAVEOPT, \
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XSAVES, X86_FEATURE_XSAVES) \
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"\n" \
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"xor %[err], %[err]\n" \
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"3:\n" \
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".pushsection .fixup,\"ax\"\n" \
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"4: movl $-2, %[err]\n" \
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"jmp 3b\n" \
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".popsection\n" \
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_ASM_EXTABLE(661b, 4b) \
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: [err] "=r" (err) \
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: "D" (st), "m" (*st), "a" (lmask), "d" (hmask) \
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: "memory")
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/*
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* Use XRSTORS to restore context if it is enabled. XRSTORS supports compact
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* XSAVE area format.
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*/
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#define XSTATE_XRESTORE(st, lmask, hmask, err) \
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asm volatile(ALTERNATIVE(XRSTOR, \
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XRSTORS, X86_FEATURE_XSAVES) \
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"\n" \
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"xor %[err], %[err]\n" \
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"3:\n" \
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".pushsection .fixup,\"ax\"\n" \
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"4: movl $-2, %[err]\n" \
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"jmp 3b\n" \
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".popsection\n" \
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_ASM_EXTABLE(661b, 4b) \
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: [err] "=r" (err) \
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: "D" (st), "m" (*st), "a" (lmask), "d" (hmask) \
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: "memory")
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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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@ -303,33 +338,11 @@ static inline void copy_xregs_to_kernel(struct xregs_state *xstate)
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u64 mask = -1;
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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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int err;
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WARN_ON(!alternatives_patched);
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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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[xstate] "D" (xstate), "a" (lmask), "d" (hmask) :
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"memory");
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asm volatile("2:\n\t"
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xstate_fault(err)
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: "0" (err)
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: "memory");
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XSTATE_XSAVE(xstate, lmask, hmask, err);
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/* We should never fault when copying to a kernel buffer: */
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WARN_ON_FPU(err);
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@ -342,23 +355,9 @@ static inline void copy_kernel_to_xregs(struct xregs_state *xstate, 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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int err;
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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" (xstate), "m" (*xstate), "a" (lmask), "d" (hmask)
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: "memory");
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asm volatile("2:\n"
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xstate_fault(err)
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: "0" (err)
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: "memory");
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XSTATE_XRESTORE(xstate, lmask, hmask, err);
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/* We should never fault when copying from a kernel buffer: */
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WARN_ON_FPU(err);
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