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-rw-r--r--arch/x86/kernel/cpu/common.c5
-rw-r--r--arch/x86/kernel/i387.c5
-rw-r--r--arch/x86/kernel/traps_64.c2
-rw-r--r--include/asm-x86/i387.h64
-rw-r--r--include/asm-x86/processor.h1
-rw-r--r--include/asm-x86/thread_info.h1
-rw-r--r--include/asm-x86/xsave.h35
7 files changed, 104 insertions, 9 deletions
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index fabbcb7..6c2b9e7 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -709,7 +709,10 @@ void __cpuinit cpu_init(void)
/*
* Force FPU initialization:
*/
- current_thread_info()->status = 0;
+ if (cpu_has_xsave)
+ current_thread_info()->status = TS_XSAVE;
+ else
+ current_thread_info()->status = 0;
clear_used_math();
mxcsr_feature_mask_init();
diff --git a/arch/x86/kernel/i387.c b/arch/x86/kernel/i387.c
index e22a9a9..b778e17 100644
--- a/arch/x86/kernel/i387.c
+++ b/arch/x86/kernel/i387.c
@@ -97,7 +97,10 @@ void __cpuinit fpu_init(void)
mxcsr_feature_mask_init();
/* clean state in init */
- current_thread_info()->status = 0;
+ if (cpu_has_xsave)
+ current_thread_info()->status = TS_XSAVE;
+ else
+ current_thread_info()->status = 0;
clear_used_math();
}
#endif /* CONFIG_X86_64 */
diff --git a/arch/x86/kernel/traps_64.c b/arch/x86/kernel/traps_64.c
index 3580a79..38eb761 100644
--- a/arch/x86/kernel/traps_64.c
+++ b/arch/x86/kernel/traps_64.c
@@ -1134,7 +1134,7 @@ asmlinkage void math_state_restore(void)
/*
* Paranoid restore. send a SIGSEGV if we fail to restore the state.
*/
- if (unlikely(restore_fpu_checking(&me->thread.xstate->fxsave))) {
+ if (unlikely(restore_fpu_checking(me))) {
stts();
force_sig(SIGSEGV, me);
return;
diff --git a/include/asm-x86/i387.h b/include/asm-x86/i387.h
index 6a66478..a6d256f 100644
--- a/include/asm-x86/i387.h
+++ b/include/asm-x86/i387.h
@@ -36,6 +36,8 @@ extern int save_i387_ia32(struct _fpstate_ia32 __user *buf);
extern int restore_i387_ia32(struct _fpstate_ia32 __user *buf);
#endif
+#define X87_FSW_ES (1 << 7) /* Exception Summary */
+
#ifdef CONFIG_X86_64
/* Ignore delayed exceptions from user space */
@@ -46,7 +48,7 @@ static inline void tolerant_fwait(void)
_ASM_EXTABLE(1b, 2b));
}
-static inline int restore_fpu_checking(struct i387_fxsave_struct *fx)
+static inline int fxrstor_checking(struct i387_fxsave_struct *fx)
{
int err;
@@ -66,15 +68,31 @@ static inline int restore_fpu_checking(struct i387_fxsave_struct *fx)
return err;
}
-#define X87_FSW_ES (1 << 7) /* Exception Summary */
+static inline int restore_fpu_checking(struct task_struct *tsk)
+{
+ if (task_thread_info(tsk)->status & TS_XSAVE)
+ return xrstor_checking(&tsk->thread.xstate->xsave);
+ else
+ return fxrstor_checking(&tsk->thread.xstate->fxsave);
+}
/* AMD CPUs don't save/restore FDP/FIP/FOP unless an exception
is pending. Clear the x87 state here by setting it to fixed
values. The kernel data segment can be sometimes 0 and sometimes
new user value. Both should be ok.
Use the PDA as safe address because it should be already in L1. */
-static inline void clear_fpu_state(struct i387_fxsave_struct *fx)
+static inline void clear_fpu_state(struct task_struct *tsk)
{
+ struct xsave_struct *xstate = &tsk->thread.xstate->xsave;
+ struct i387_fxsave_struct *fx = &tsk->thread.xstate->fxsave;
+
+ /*
+ * xsave header may indicate the init state of the FP.
+ */
+ if ((task_thread_info(tsk)->status & TS_XSAVE) &&
+ !(xstate->xsave_hdr.xstate_bv & XSTATE_FP))
+ return;
+
if (unlikely(fx->swd & X87_FSW_ES))
asm volatile("fnclex");
alternative_input(ASM_NOP8 ASM_NOP2,
@@ -107,7 +125,7 @@ static inline int save_i387_checking(struct i387_fxsave_struct __user *fx)
return err;
}
-static inline void __save_init_fpu(struct task_struct *tsk)
+static inline void fxsave(struct task_struct *tsk)
{
/* Using "rex64; fxsave %0" is broken because, if the memory operand
uses any extended registers for addressing, a second REX prefix
@@ -132,7 +150,16 @@ static inline void __save_init_fpu(struct task_struct *tsk)
: "=m" (tsk->thread.xstate->fxsave)
: "cdaSDb" (&tsk->thread.xstate->fxsave));
#endif
- clear_fpu_state(&tsk->thread.xstate->fxsave);
+}
+
+static inline void __save_init_fpu(struct task_struct *tsk)
+{
+ if (task_thread_info(tsk)->status & TS_XSAVE)
+ xsave(tsk);
+ else
+ fxsave(tsk);
+
+ clear_fpu_state(tsk);
task_thread_info(tsk)->status &= ~TS_USEDFPU;
}
@@ -147,6 +174,10 @@ static inline void tolerant_fwait(void)
static inline void restore_fpu(struct task_struct *tsk)
{
+ if (task_thread_info(tsk)->status & TS_XSAVE) {
+ xrstor_checking(&tsk->thread.xstate->xsave);
+ return;
+ }
/*
* The "nop" is needed to make the instructions the same
* length.
@@ -172,6 +203,27 @@ static inline void restore_fpu(struct task_struct *tsk)
*/
static inline void __save_init_fpu(struct task_struct *tsk)
{
+ if (task_thread_info(tsk)->status & TS_XSAVE) {
+ struct xsave_struct *xstate = &tsk->thread.xstate->xsave;
+ struct i387_fxsave_struct *fx = &tsk->thread.xstate->fxsave;
+
+ xsave(tsk);
+
+ /*
+ * xsave header may indicate the init state of the FP.
+ */
+ if (!(xstate->xsave_hdr.xstate_bv & XSTATE_FP))
+ goto end;
+
+ if (unlikely(fx->swd & X87_FSW_ES))
+ asm volatile("fnclex");
+
+ /*
+ * we can do a simple return here or be paranoid :)
+ */
+ goto clear_state;
+ }
+
/* Use more nops than strictly needed in case the compiler
varies code */
alternative_input(
@@ -181,6 +233,7 @@ static inline void __save_init_fpu(struct task_struct *tsk)
X86_FEATURE_FXSR,
[fx] "m" (tsk->thread.xstate->fxsave),
[fsw] "m" (tsk->thread.xstate->fxsave.swd) : "memory");
+clear_state:
/* AMD K7/K8 CPUs don't save/restore FDP/FIP/FOP unless an exception
is pending. Clear the x87 state here by setting it to fixed
values. safe_address is a random variable that should be in L1 */
@@ -190,6 +243,7 @@ static inline void __save_init_fpu(struct task_struct *tsk)
"fildl %[addr]", /* set F?P to defined value */
X86_FEATURE_FXSAVE_LEAK,
[addr] "m" (safe_address));
+end:
task_thread_info(tsk)->status &= ~TS_USEDFPU;
}
diff --git a/include/asm-x86/processor.h b/include/asm-x86/processor.h
index d7c0221..77b7af6 100644
--- a/include/asm-x86/processor.h
+++ b/include/asm-x86/processor.h
@@ -362,6 +362,7 @@ union thread_xstate {
struct i387_fsave_struct fsave;
struct i387_fxsave_struct fxsave;
struct i387_soft_struct soft;
+ struct xsave_struct xsave;
};
#ifdef CONFIG_X86_64
diff --git a/include/asm-x86/thread_info.h b/include/asm-x86/thread_info.h
index e64be88..30586f2 100644
--- a/include/asm-x86/thread_info.h
+++ b/include/asm-x86/thread_info.h
@@ -239,6 +239,7 @@ static inline struct thread_info *stack_thread_info(void)
#define TS_POLLING 0x0004 /* true if in idle loop
and not sleeping */
#define TS_RESTORE_SIGMASK 0x0008 /* restore signal mask in do_signal() */
+#define TS_XSAVE 0x0010 /* Use xsave/xrstor */
#define tsk_is_polling(t) (task_thread_info(t)->status & TS_POLLING)
diff --git a/include/asm-x86/xsave.h b/include/asm-x86/xsave.h
index 6d70e62..e835a91 100644
--- a/include/asm-x86/xsave.h
+++ b/include/asm-x86/xsave.h
@@ -17,10 +17,43 @@
#define XCNTXT_LMASK (XSTATE_FP | XSTATE_SSE)
#define XCNTXT_HMASK 0x0
+#ifdef CONFIG_X86_64
+#define REX_PREFIX "0x48, "
+#else
+#define REX_PREFIX
+#endif
+
extern unsigned int xstate_size, pcntxt_hmask, pcntxt_lmask;
extern struct xsave_struct *init_xstate_buf;
extern void xsave_cntxt_init(void);
extern void xsave_init(void);
-
+extern int init_fpu(struct task_struct *child);
+
+static inline int xrstor_checking(struct xsave_struct *fx)
+{
+ int err;
+
+ asm volatile("1: .byte " REX_PREFIX "0x0f,0xae,0x2f\n\t"
+ "2:\n"
+ ".section .fixup,\"ax\"\n"
+ "3: movl $-1,%[err]\n"
+ " jmp 2b\n"
+ ".previous\n"
+ _ASM_EXTABLE(1b, 3b)
+ : [err] "=r" (err)
+ : "D" (fx), "m" (*fx), "a" (-1), "d" (-1), "0" (0)
+ : "memory");
+
+ return err;
+}
+
+static inline void xsave(struct task_struct *tsk)
+{
+ /* This, however, we can work around by forcing the compiler to select
+ an addressing mode that doesn't require extended registers. */
+ __asm__ __volatile__(".byte " REX_PREFIX "0x0f,0xae,0x27"
+ : : "D" (&(tsk->thread.xstate->xsave)),
+ "a" (-1), "d"(-1) : "memory");
+}
#endif
generated by cgit v1.1 at 2024-10-30 12:51:54 +0000