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| Started by | Borislav Petkov <bp@alien8.de> |
|---|---|
| First post | 2015-11-19 12:30 +0100 |
| Last post | 2015-11-24 10:40 +0100 |
| Articles | 2 — 2 participants |
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[RFC PATCH 1/2] x86/fpu: Add an XSTATE_OP macro Borislav Petkov <bp@alien8.de> - 2015-11-19 12:30 +0100
[tip:x86/fpu] x86/fpu: Add an XSTATE_OP() macro tip-bot for Borislav Petkov <tipbot@zytor.com> - 2015-11-24 10:40 +0100
| From | Borislav Petkov <bp@alien8.de> |
|---|---|
| Date | 2015-11-19 12:30 +0100 |
| Subject | [RFC PATCH 1/2] x86/fpu: Add an XSTATE_OP macro |
| Message-ID | <qwvzA-by-13@gated-at.bofh.it> |
From: Borislav Petkov <bp@suse.de>
Add an XSTATE_OP macro which contains the XSAVE* fault handling and
replace all non-alternatives users of xstate_fault() with it.
This fixes also the buglet in copy_xregs_to_user() and
copy_user_to_xregs() where the inline asm didn't have @xstate as memory
reference and thus potentially causing unwanted reordering of accesses
to the extended state.
Signed-off-by: Borislav Petkov <bp@suse.de>
---
arch/x86/include/asm/fpu/internal.h | 68 +++++++++++++++++--------------------
1 file changed, 31 insertions(+), 37 deletions(-)
diff --git a/arch/x86/include/asm/fpu/internal.h b/arch/x86/include/asm/fpu/internal.h
index 3c3550c3a4a3..709a3df8ab37 100644
--- a/arch/x86/include/asm/fpu/internal.h
+++ b/arch/x86/include/asm/fpu/internal.h
@@ -237,6 +237,20 @@ static inline void copy_fxregs_to_kernel(struct fpu *fpu)
_ASM_EXTABLE(1b, 3b) \
: [_err] "=r" (__err)
+#define XSTATE_OP(op, st, lmask, hmask, err) \
+ asm volatile("1:" op "\n\t" \
+ "xor %[err], %[err]\n" \
+ "2:\n\t" \
+ ".pushsection .fixup,\"ax\"\n\t" \
+ "3: movl $-2,%[err]\n\t" \
+ "jmp 2b\n\t" \
+ ".popsection\n\t" \
+ _ASM_EXTABLE(1b, 3b) \
+ : [err] "=r" (err) \
+ : "D" (st), "m" (*st), "a" (lmask), "d" (hmask) \
+ : "memory")
+
+
/*
* This function is called only during boot time when x86 caps are not set
* up and alternative can not be used yet.
@@ -246,22 +260,14 @@ static inline void copy_xregs_to_kernel_booting(struct xregs_state *xstate)
u64 mask = -1;
u32 lmask = mask;
u32 hmask = mask >> 32;
- int err = 0;
+ int err;
WARN_ON(system_state != SYSTEM_BOOTING);
- if (boot_cpu_has(X86_FEATURE_XSAVES))
- asm volatile("1:"XSAVES"\n\t"
- "2:\n\t"
- xstate_fault(err)
- : "D" (xstate), "m" (*xstate), "a" (lmask), "d" (hmask), "0" (err)
- : "memory");
+ if (static_cpu_has_safe(X86_FEATURE_XSAVES))
+ XSTATE_OP(XSAVES, xstate, lmask, hmask, err);
else
- asm volatile("1:"XSAVE"\n\t"
- "2:\n\t"
- xstate_fault(err)
- : "D" (xstate), "m" (*xstate), "a" (lmask), "d" (hmask), "0" (err)
- : "memory");
+ XSTATE_OP(XSAVE, xstate, lmask, hmask, err);
/* We should never fault when copying to a kernel buffer: */
WARN_ON_FPU(err);
@@ -276,22 +282,14 @@ static inline void copy_kernel_to_xregs_booting(struct xregs_state *xstate)
u64 mask = -1;
u32 lmask = mask;
u32 hmask = mask >> 32;
- int err = 0;
+ int err;
WARN_ON(system_state != SYSTEM_BOOTING);
- if (boot_cpu_has(X86_FEATURE_XSAVES))
- asm volatile("1:"XRSTORS"\n\t"
- "2:\n\t"
- xstate_fault(err)
- : "D" (xstate), "m" (*xstate), "a" (lmask), "d" (hmask), "0" (err)
- : "memory");
+ if (static_cpu_has_safe(X86_FEATURE_XSAVES))
+ XSTATE_OP(XRSTORS, xstate, lmask, hmask, err);
else
- asm volatile("1:"XRSTOR"\n\t"
- "2:\n\t"
- xstate_fault(err)
- : "D" (xstate), "m" (*xstate), "a" (lmask), "d" (hmask), "0" (err)
- : "memory");
+ XSTATE_OP(XRSTOR, xstate, lmask, hmask, err);
/* We should never fault when copying from a kernel buffer: */
WARN_ON_FPU(err);
@@ -388,12 +386,10 @@ static inline int copy_xregs_to_user(struct xregs_state __user *buf)
if (unlikely(err))
return -EFAULT;
- __asm__ __volatile__(ASM_STAC "\n"
- "1:"XSAVE"\n"
- "2: " ASM_CLAC "\n"
- xstate_fault(err)
- : "D" (buf), "a" (-1), "d" (-1), "0" (err)
- : "memory");
+ stac();
+ XSTATE_OP(XSAVE, buf, -1, -1, err);
+ clac();
+
return err;
}
@@ -405,14 +401,12 @@ static inline int copy_user_to_xregs(struct xregs_state __user *buf, u64 mask)
struct xregs_state *xstate = ((__force struct xregs_state *)buf);
u32 lmask = mask;
u32 hmask = mask >> 32;
- int err = 0;
+ int err;
+
+ stac();
+ XSTATE_OP(XRSTOR, xstate, lmask, hmask, err);
+ clac();
- __asm__ __volatile__(ASM_STAC "\n"
- "1:"XRSTOR"\n"
- "2: " ASM_CLAC "\n"
- xstate_fault(err)
- : "D" (xstate), "a" (lmask), "d" (hmask), "0" (err)
- : "memory"); /* memory required? */
return err;
}
--
2.3.5
--
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| From | tip-bot for Borislav Petkov <tipbot@zytor.com> |
|---|---|
| Date | 2015-11-24 10:40 +0100 |
| Subject | [tip:x86/fpu] x86/fpu: Add an XSTATE_OP() macro |
| Message-ID | <qyieS-6jd-3@gated-at.bofh.it> |
| In reply to | #1273048 |
Commit-ID: b74a0cf1b3db30173eefa00c411775d2b1697700
Gitweb: http://git.kernel.org/tip/b74a0cf1b3db30173eefa00c411775d2b1697700
Author: Borislav Petkov <bp@suse.de>
AuthorDate: Thu, 19 Nov 2015 12:25:25 +0100
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 24 Nov 2015 09:52:52 +0100
x86/fpu: Add an XSTATE_OP() macro
Add an XSTATE_OP() macro which contains the XSAVE* fault handling
and replace all non-alternatives users of xstate_fault() with
it.
This fixes also the buglet in copy_xregs_to_user() and
copy_user_to_xregs() where the inline asm didn't have @xstate as
memory reference and thus potentially causing unwanted
reordering of accesses to the extended state.
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/1447932326-4371-2-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/include/asm/fpu/internal.h | 68 +++++++++++++++++--------------------
1 file changed, 31 insertions(+), 37 deletions(-)
diff --git a/arch/x86/include/asm/fpu/internal.h b/arch/x86/include/asm/fpu/internal.h
index 3c3550c..709a3df 100644
--- a/arch/x86/include/asm/fpu/internal.h
+++ b/arch/x86/include/asm/fpu/internal.h
@@ -237,6 +237,20 @@ static inline void copy_fxregs_to_kernel(struct fpu *fpu)
_ASM_EXTABLE(1b, 3b) \
: [_err] "=r" (__err)
+#define XSTATE_OP(op, st, lmask, hmask, err) \
+ asm volatile("1:" op "\n\t" \
+ "xor %[err], %[err]\n" \
+ "2:\n\t" \
+ ".pushsection .fixup,\"ax\"\n\t" \
+ "3: movl $-2,%[err]\n\t" \
+ "jmp 2b\n\t" \
+ ".popsection\n\t" \
+ _ASM_EXTABLE(1b, 3b) \
+ : [err] "=r" (err) \
+ : "D" (st), "m" (*st), "a" (lmask), "d" (hmask) \
+ : "memory")
+
+
/*
* This function is called only during boot time when x86 caps are not set
* up and alternative can not be used yet.
@@ -246,22 +260,14 @@ static inline void copy_xregs_to_kernel_booting(struct xregs_state *xstate)
u64 mask = -1;
u32 lmask = mask;
u32 hmask = mask >> 32;
- int err = 0;
+ int err;
WARN_ON(system_state != SYSTEM_BOOTING);
- if (boot_cpu_has(X86_FEATURE_XSAVES))
- asm volatile("1:"XSAVES"\n\t"
- "2:\n\t"
- xstate_fault(err)
- : "D" (xstate), "m" (*xstate), "a" (lmask), "d" (hmask), "0" (err)
- : "memory");
+ if (static_cpu_has_safe(X86_FEATURE_XSAVES))
+ XSTATE_OP(XSAVES, xstate, lmask, hmask, err);
else
- asm volatile("1:"XSAVE"\n\t"
- "2:\n\t"
- xstate_fault(err)
- : "D" (xstate), "m" (*xstate), "a" (lmask), "d" (hmask), "0" (err)
- : "memory");
+ XSTATE_OP(XSAVE, xstate, lmask, hmask, err);
/* We should never fault when copying to a kernel buffer: */
WARN_ON_FPU(err);
@@ -276,22 +282,14 @@ static inline void copy_kernel_to_xregs_booting(struct xregs_state *xstate)
u64 mask = -1;
u32 lmask = mask;
u32 hmask = mask >> 32;
- int err = 0;
+ int err;
WARN_ON(system_state != SYSTEM_BOOTING);
- if (boot_cpu_has(X86_FEATURE_XSAVES))
- asm volatile("1:"XRSTORS"\n\t"
- "2:\n\t"
- xstate_fault(err)
- : "D" (xstate), "m" (*xstate), "a" (lmask), "d" (hmask), "0" (err)
- : "memory");
+ if (static_cpu_has_safe(X86_FEATURE_XSAVES))
+ XSTATE_OP(XRSTORS, xstate, lmask, hmask, err);
else
- asm volatile("1:"XRSTOR"\n\t"
- "2:\n\t"
- xstate_fault(err)
- : "D" (xstate), "m" (*xstate), "a" (lmask), "d" (hmask), "0" (err)
- : "memory");
+ XSTATE_OP(XRSTOR, xstate, lmask, hmask, err);
/* We should never fault when copying from a kernel buffer: */
WARN_ON_FPU(err);
@@ -388,12 +386,10 @@ static inline int copy_xregs_to_user(struct xregs_state __user *buf)
if (unlikely(err))
return -EFAULT;
- __asm__ __volatile__(ASM_STAC "\n"
- "1:"XSAVE"\n"
- "2: " ASM_CLAC "\n"
- xstate_fault(err)
- : "D" (buf), "a" (-1), "d" (-1), "0" (err)
- : "memory");
+ stac();
+ XSTATE_OP(XSAVE, buf, -1, -1, err);
+ clac();
+
return err;
}
@@ -405,14 +401,12 @@ static inline int copy_user_to_xregs(struct xregs_state __user *buf, u64 mask)
struct xregs_state *xstate = ((__force struct xregs_state *)buf);
u32 lmask = mask;
u32 hmask = mask >> 32;
- int err = 0;
+ int err;
+
+ stac();
+ XSTATE_OP(XRSTOR, xstate, lmask, hmask, err);
+ clac();
- __asm__ __volatile__(ASM_STAC "\n"
- "1:"XRSTOR"\n"
- "2: " ASM_CLAC "\n"
- xstate_fault(err)
- : "D" (xstate), "a" (lmask), "d" (hmask), "0" (err)
- : "memory"); /* memory required? */
return err;
}
--
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