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Subject[RFC 1/2] x86, xsave: cleanup xsave/xrstor support
Date
Removed the functions fpu_fxrstor_checking() and restore_fpu_checking()
because they weren't doing anything. Removed redundant xsave/xrstor
implementations. Since xsave/xrstor is not specific to the FPU, and also
for consistency, all xsave/xrstor functions now take a xsave_struct
argument.

Signed-off-by: Hans Rosenfeld <hans.rosenfeld@amd.com>
---
arch/x86/include/asm/i387.h | 20 +++-------
arch/x86/include/asm/xsave.h | 81 +++++++++++++++---------------------------
arch/x86/kernel/traps.c | 2 +-
arch/x86/kernel/xsave.c | 4 +-
4 files changed, 38 insertions(+), 69 deletions(-)
diff --git a/arch/x86/include/asm/i387.h b/arch/x86/include/asm/i387.h
index ef32890..d908383 100644
--- a/arch/x86/include/asm/i387.h
+++ b/arch/x86/include/asm/i387.h
@@ -227,12 +227,14 @@ static inline void fpu_fxsave(struct fpu *fpu)
static inline void fpu_save_init(struct fpu *fpu)
{
if (use_xsave()) {
- fpu_xsave(fpu);
+ struct xsave_struct *xstate = &fpu->state->xsave;
+
+ fpu_xsave(xstate);

/*
* xsave header may indicate the init state of the FP.
*/
- if (!(fpu->state->xsave.xsave_hdr.xstate_bv & XSTATE_FP))
+ if (!(xstate->xsave_hdr.xstate_bv & XSTATE_FP))
return;
} else if (use_fxsr()) {
fpu_fxsave(fpu);
@@ -262,22 +264,12 @@ static inline void __save_init_fpu(struct task_struct *tsk)
task_thread_info(tsk)->status &= ~TS_USEDFPU;
}

-static inline int fpu_fxrstor_checking(struct fpu *fpu)
-{
- return fxrstor_checking(&fpu->state->fxsave);
-}
-
static inline int fpu_restore_checking(struct fpu *fpu)
{
if (use_xsave())
- return fpu_xrstor_checking(fpu);
+ return xrstor_checking(&fpu->state->xsave, -1);
else
- return fpu_fxrstor_checking(fpu);
-}
-
-static inline int restore_fpu_checking(struct task_struct *tsk)
-{
- return fpu_restore_checking(&tsk->thread.fpu);
+ return fxrstor_checking(&fpu->state->fxsave);
}

/*
diff --git a/arch/x86/include/asm/xsave.h b/arch/x86/include/asm/xsave.h
index c6ce245..8bcbbce 100644
--- a/arch/x86/include/asm/xsave.h
+++ b/arch/x86/include/asm/xsave.h
@@ -42,10 +42,11 @@ extern int check_for_xstate(struct i387_fxsave_struct __user *buf,
void __user *fpstate,
struct _fpx_sw_bytes *sw);

-static inline int fpu_xrstor_checking(struct fpu *fpu)
+static inline int xrstor_checking(struct xsave_struct *fx, u64 mask)
{
- struct xsave_struct *fx = &fpu->state->xsave;
int err;
+ u32 lmask = mask;
+ u32 hmask = mask >> 32;

asm volatile("1: .byte " REX_PREFIX "0x0f,0xae,0x2f\n\t"
"2:\n"
@@ -55,13 +56,23 @@ static inline int fpu_xrstor_checking(struct fpu *fpu)
".previous\n"
_ASM_EXTABLE(1b, 3b)
: [err] "=r" (err)
- : "D" (fx), "m" (*fx), "a" (-1), "d" (-1), "0" (0)
+ : "D" (fx), "m" (*fx), "a" (lmask), "d" (hmask), "0" (0)
: "memory");

return err;
}

-static inline int xsave_user(struct xsave_struct __user *buf)
+static inline void xrstor_state(struct xsave_struct *fx, u64 mask)
+{
+ u32 lmask = mask;
+ u32 hmask = mask >> 32;
+
+ asm volatile(".byte " REX_PREFIX "0x0f,0xae,0x2f\n\t"
+ : : "D" (fx), "m" (*fx), "a" (lmask), "d" (hmask)
+ : "memory");
+}
+
+static inline int xsave_checking(struct xsave_struct __user *buf)
{
int err;

@@ -74,58 +85,24 @@ static inline int xsave_user(struct xsave_struct __user *buf)
if (unlikely(err))
return -EFAULT;

- __asm__ __volatile__("1: .byte " REX_PREFIX "0x0f,0xae,0x27\n"
- "2:\n"
- ".section .fixup,\"ax\"\n"
- "3: movl $-1,%[err]\n"
- " jmp 2b\n"
- ".previous\n"
- ".section __ex_table,\"a\"\n"
- _ASM_ALIGN "\n"
- _ASM_PTR "1b,3b\n"
- ".previous"
- : [err] "=r" (err)
- : "D" (buf), "a" (-1), "d" (-1), "0" (0)
- : "memory");
+ asm volatile("1: .byte " REX_PREFIX "0x0f,0xae,0x27\n"
+ "2:\n"
+ ".section .fixup,\"ax\"\n"
+ "3: movl $-1,%[err]\n"
+ " jmp 2b\n"
+ ".previous\n"
+ _ASM_EXTABLE(1b,3b)
+ : [err] "=r" (err)
+ : "D" (buf), "a" (-1), "d" (-1), "0" (0)
+ : "memory");
+
if (unlikely(err) && __clear_user(buf, xstate_size))
err = -EFAULT;
- /* No need to clear here because the caller clears USED_MATH */
- return err;
-}
-
-static inline int xrestore_user(struct xsave_struct __user *buf, u64 mask)
-{
- int err;
- struct xsave_struct *xstate = ((__force struct xsave_struct *)buf);
- u32 lmask = mask;
- u32 hmask = mask >> 32;

- __asm__ __volatile__("1: .byte " REX_PREFIX "0x0f,0xae,0x2f\n"
- "2:\n"
- ".section .fixup,\"ax\"\n"
- "3: movl $-1,%[err]\n"
- " jmp 2b\n"
- ".previous\n"
- ".section __ex_table,\"a\"\n"
- _ASM_ALIGN "\n"
- _ASM_PTR "1b,3b\n"
- ".previous"
- : [err] "=r" (err)
- : "D" (xstate), "a" (lmask), "d" (hmask), "0" (0)
- : "memory"); /* memory required? */
+ /* No need to clear here because the caller clears USED_MATH */
return err;
}

-static inline void xrstor_state(struct xsave_struct *fx, u64 mask)
-{
- u32 lmask = mask;
- u32 hmask = mask >> 32;
-
- asm volatile(".byte " REX_PREFIX "0x0f,0xae,0x2f\n\t"
- : : "D" (fx), "m" (*fx), "a" (lmask), "d" (hmask)
- : "memory");
-}
-
static inline void xsave_state(struct xsave_struct *fx, u64 mask)
{
u32 lmask = mask;
@@ -136,7 +113,7 @@ static inline void xsave_state(struct xsave_struct *fx, u64 mask)
: "memory");
}

-static inline void fpu_xsave(struct fpu *fpu)
+static inline void fpu_xsave(struct xsave_struct *fx)
{
/* This, however, we can work around by forcing the compiler to select
an addressing mode that doesn't require extended registers. */
@@ -144,7 +121,7 @@ static inline void fpu_xsave(struct fpu *fpu)
".byte " REX_PREFIX "0x0f,0xae,0x27",
".byte " REX_PREFIX "0x0f,0xae,0x37",
X86_FEATURE_XSAVEOPT,
- [fx] "D" (&fpu->state->xsave), "a" (-1), "d" (-1) :
+ [fx] "D" (fx), "a" (-1), "d" (-1) :
"memory");
}
#endif
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index f02c179..1b0d148 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -720,7 +720,7 @@ void __math_state_restore(void)
/*
* Paranoid restore. send a SIGSEGV if we fail to restore the state.
*/
- if (unlikely(restore_fpu_checking(tsk))) {
+ if (unlikely(fpu_restore_checking(&tsk->thread.fpu))) {
stts();
force_sig(SIGSEGV, tsk);
return;
diff --git a/arch/x86/kernel/xsave.c b/arch/x86/kernel/xsave.c
index 9c253bd..5eb15d4 100644
--- a/arch/x86/kernel/xsave.c
+++ b/arch/x86/kernel/xsave.c
@@ -170,7 +170,7 @@ int save_i387_xstate(void __user *buf)

if (task_thread_info(tsk)->status & TS_USEDFPU) {
if (use_xsave())
- err = xsave_user(buf);
+ err = xsave_checking(buf);
else
err = fxsave_user(buf);

@@ -247,7 +247,7 @@ static int restore_user_xstate(void __user *buf)
/*
* restore the state passed by the user.
*/
- err = xrestore_user(buf, mask);
+ err = xrstor_checking((__force struct xsave_struct *)buf, mask);
if (err)
return err;

--
1.5.6.5



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