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authorLinus Torvalds <torvalds@linux-foundation.org>2014-08-13 18:20:04 -0600
committerLinus Torvalds <torvalds@linux-foundation.org>2014-08-13 18:20:04 -0600
commit7453f33b2e07fc2835e24cda0893de83c78d8d76 (patch)
tree02d82193515fcc94cf39e284fd325c4491913331 /arch/x86/include
parentfd1cf90580289f83f9c972bb367a74d846d281c4 (diff)
parentd0f2dd186133a0241a2ccefb188a0e49e8187859 (diff)
downloadlinux-7453f33b2e07fc2835e24cda0893de83c78d8d76.tar.gz
Merge branch 'x86-xsave-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86/xsave changes from Peter Anvin: "This is a patchset to support the XSAVES instruction required to support context switch of supervisor-only features in upcoming silicon. This patchset missed the 3.16 merge window, which is why it is based on 3.15-rc7" * 'x86-xsave-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86, xsave: Add forgotten inline annotation x86/xsaves: Clean up code in xstate offsets computation in xsave area x86/xsave: Make it clear that the XSAVE macros use (%edi)/(%rdi) Define kernel API to get address of each state in xsave area x86/xsaves: Enable xsaves/xrstors x86/xsaves: Call booting time xsaves and xrstors in setup_init_fpu_buf x86/xsaves: Save xstate to task's xsave area in __save_fpu during booting time x86/xsaves: Add xsaves and xrstors support for booting time x86/xsaves: Clear reserved bits in xsave header x86/xsaves: Use xsave/xrstor for saving and restoring user space context x86/xsaves: Use xsaves/xrstors for context switch x86/xsaves: Use xsaves/xrstors to save and restore xsave area x86/xsaves: Define a macro for handling xsave/xrstor instruction fault x86/xsaves: Define macros for xsave instructions x86/xsaves: Change compacted format xsave area header x86/alternative: Add alternative_input_2 to support alternative with two features and input x86/xsaves: Add a kernel parameter noxsaves to disable xsaves/xrstors
Diffstat (limited to 'arch/x86/include')
-rw-r--r--arch/x86/include/asm/alternative.h14
-rw-r--r--arch/x86/include/asm/fpu-internal.h9
-rw-r--r--arch/x86/include/asm/processor.h4
-rw-r--r--arch/x86/include/asm/xsave.h223
4 files changed, 189 insertions, 61 deletions
diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index 0a3f9c9f98d..473bdbee378 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -161,6 +161,20 @@ static inline int alternatives_text_reserved(void *start, void *end)
asm volatile (ALTERNATIVE(oldinstr, newinstr, feature) \
: : "i" (0), ## input)
+/*
+ * This is similar to alternative_input. But it has two features and
+ * respective instructions.
+ *
+ * If CPU has feature2, newinstr2 is used.
+ * Otherwise, if CPU has feature1, newinstr1 is used.
+ * Otherwise, oldinstr is used.
+ */
+#define alternative_input_2(oldinstr, newinstr1, feature1, newinstr2, \
+ feature2, input...) \
+ asm volatile(ALTERNATIVE_2(oldinstr, newinstr1, feature1, \
+ newinstr2, feature2) \
+ : : "i" (0), ## input)
+
/* Like alternative_input, but with a single output argument */
#define alternative_io(oldinstr, newinstr, feature, output, input...) \
asm volatile (ALTERNATIVE(oldinstr, newinstr, feature) \
diff --git a/arch/x86/include/asm/fpu-internal.h b/arch/x86/include/asm/fpu-internal.h
index e3b85422cf1..412ececa00b 100644
--- a/arch/x86/include/asm/fpu-internal.h
+++ b/arch/x86/include/asm/fpu-internal.h
@@ -508,9 +508,12 @@ static inline void user_fpu_begin(void)
static inline void __save_fpu(struct task_struct *tsk)
{
- if (use_xsave())
- xsave_state(&tsk->thread.fpu.state->xsave, -1);
- else
+ if (use_xsave()) {
+ if (unlikely(system_state == SYSTEM_BOOTING))
+ xsave_state_booting(&tsk->thread.fpu.state->xsave, -1);
+ else
+ xsave_state(&tsk->thread.fpu.state->xsave, -1);
+ } else
fpu_fxsave(&tsk->thread.fpu);
}
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index ee30b9f0b91..eb71ec79473 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -385,8 +385,8 @@ struct bndcsr_struct {
struct xsave_hdr_struct {
u64 xstate_bv;
- u64 reserved1[2];
- u64 reserved2[5];
+ u64 xcomp_bv;
+ u64 reserved[6];
} __attribute__((packed));
struct xsave_struct {
diff --git a/arch/x86/include/asm/xsave.h b/arch/x86/include/asm/xsave.h
index d949ef28c48..7e7a79ada65 100644
--- a/arch/x86/include/asm/xsave.h
+++ b/arch/x86/include/asm/xsave.h
@@ -52,24 +52,170 @@ extern void xsave_init(void);
extern void update_regset_xstate_info(unsigned int size, u64 xstate_mask);
extern int init_fpu(struct task_struct *child);
-static inline int fpu_xrstor_checking(struct xsave_struct *fx)
+/* These macros all use (%edi)/(%rdi) as the single memory argument. */
+#define XSAVE ".byte " REX_PREFIX "0x0f,0xae,0x27"
+#define XSAVEOPT ".byte " REX_PREFIX "0x0f,0xae,0x37"
+#define XSAVES ".byte " REX_PREFIX "0x0f,0xc7,0x2f"
+#define XRSTOR ".byte " REX_PREFIX "0x0f,0xae,0x2f"
+#define XRSTORS ".byte " REX_PREFIX "0x0f,0xc7,0x1f"
+
+#define xstate_fault ".section .fixup,\"ax\"\n" \
+ "3: movl $-1,%[err]\n" \
+ " jmp 2b\n" \
+ ".previous\n" \
+ _ASM_EXTABLE(1b, 3b) \
+ : [err] "=r" (err)
+
+/*
+ * This function is called only during boot time when x86 caps are not set
+ * up and alternative can not be used yet.
+ */
+static inline int xsave_state_booting(struct xsave_struct *fx, u64 mask)
{
- int err;
+ u32 lmask = mask;
+ u32 hmask = mask >> 32;
+ int err = 0;
+
+ WARN_ON(system_state != SYSTEM_BOOTING);
+
+ if (boot_cpu_has(X86_FEATURE_XSAVES))
+ asm volatile("1:"XSAVES"\n\t"
+ "2:\n\t"
+ : : "D" (fx), "m" (*fx), "a" (lmask), "d" (hmask)
+ : "memory");
+ else
+ asm volatile("1:"XSAVE"\n\t"
+ "2:\n\t"
+ : : "D" (fx), "m" (*fx), "a" (lmask), "d" (hmask)
+ : "memory");
+
+ asm volatile(xstate_fault
+ : "0" (0)
+ : "memory");
+
+ return err;
+}
+
+/*
+ * This function is called only during boot time when x86 caps are not set
+ * up and alternative can not be used yet.
+ */
+static inline int xrstor_state_booting(struct xsave_struct *fx, u64 mask)
+{
+ u32 lmask = mask;
+ u32 hmask = mask >> 32;
+ int err = 0;
+
+ WARN_ON(system_state != SYSTEM_BOOTING);
- 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)
+ if (boot_cpu_has(X86_FEATURE_XSAVES))
+ asm volatile("1:"XRSTORS"\n\t"
+ "2:\n\t"
+ : : "D" (fx), "m" (*fx), "a" (lmask), "d" (hmask)
+ : "memory");
+ else
+ asm volatile("1:"XRSTOR"\n\t"
+ "2:\n\t"
+ : : "D" (fx), "m" (*fx), "a" (lmask), "d" (hmask)
+ : "memory");
+
+ asm volatile(xstate_fault
+ : "0" (0)
+ : "memory");
+
+ return err;
+}
+
+/*
+ * Save processor xstate to xsave area.
+ */
+static inline int xsave_state(struct xsave_struct *fx, u64 mask)
+{
+ u32 lmask = mask;
+ u32 hmask = mask >> 32;
+ int err = 0;
+
+ /*
+ * If xsaves is enabled, xsaves replaces xsaveopt because
+ * it supports compact format and supervisor states in addition to
+ * modified optimization in xsaveopt.
+ *
+ * Otherwise, if xsaveopt is enabled, xsaveopt replaces xsave
+ * because xsaveopt supports modified optimization which is not
+ * supported by xsave.
+ *
+ * If none of xsaves and xsaveopt is enabled, use xsave.
+ */
+ alternative_input_2(
+ "1:"XSAVE,
+ "1:"XSAVEOPT,
+ X86_FEATURE_XSAVEOPT,
+ "1:"XSAVES,
+ X86_FEATURE_XSAVES,
+ [fx] "D" (fx), "a" (lmask), "d" (hmask) :
+ "memory");
+ asm volatile("2:\n\t"
+ xstate_fault
+ : "0" (0)
: "memory");
return err;
}
+/*
+ * Restore processor xstate from xsave area.
+ */
+static inline int xrstor_state(struct xsave_struct *fx, u64 mask)
+{
+ int err = 0;
+ u32 lmask = mask;
+ u32 hmask = mask >> 32;
+
+ /*
+ * Use xrstors to restore context if it is enabled. xrstors supports
+ * compacted format of xsave area which is not supported by xrstor.
+ */
+ alternative_input(
+ "1: " XRSTOR,
+ "1: " XRSTORS,
+ X86_FEATURE_XSAVES,
+ "D" (fx), "m" (*fx), "a" (lmask), "d" (hmask)
+ : "memory");
+
+ asm volatile("2:\n"
+ xstate_fault
+ : "0" (0)
+ : "memory");
+
+ return err;
+}
+
+/*
+ * Save xstate context for old process during context switch.
+ */
+static inline void fpu_xsave(struct fpu *fpu)
+{
+ xsave_state(&fpu->state->xsave, -1);
+}
+
+/*
+ * Restore xstate context for new process during context switch.
+ */
+static inline int fpu_xrstor_checking(struct xsave_struct *fx)
+{
+ return xrstor_state(fx, -1);
+}
+
+/*
+ * Save xstate to user space xsave area.
+ *
+ * We don't use modified optimization because xrstor/xrstors might track
+ * a different application.
+ *
+ * We don't use compacted format xsave area for
+ * backward compatibility for old applications which don't understand
+ * compacted format of xsave area.
+ */
static inline int xsave_user(struct xsave_struct __user *buf)
{
int err;
@@ -83,69 +229,34 @@ static inline int xsave_user(struct xsave_struct __user *buf)
return -EFAULT;
__asm__ __volatile__(ASM_STAC "\n"
- "1: .byte " REX_PREFIX "0x0f,0xae,0x27\n"
+ "1:"XSAVE"\n"
"2: " ASM_CLAC "\n"
- ".section .fixup,\"ax\"\n"
- "3: movl $-1,%[err]\n"
- " jmp 2b\n"
- ".previous\n"
- _ASM_EXTABLE(1b,3b)
- : [err] "=r" (err)
+ xstate_fault
: "D" (buf), "a" (-1), "d" (-1), "0" (0)
: "memory");
return err;
}
+/*
+ * Restore xstate from user space xsave area.
+ */
static inline int xrestore_user(struct xsave_struct __user *buf, u64 mask)
{
- int err;
+ int err = 0;
struct xsave_struct *xstate = ((__force struct xsave_struct *)buf);
u32 lmask = mask;
u32 hmask = mask >> 32;
__asm__ __volatile__(ASM_STAC "\n"
- "1: .byte " REX_PREFIX "0x0f,0xae,0x2f\n"
+ "1:"XRSTOR"\n"
"2: " ASM_CLAC "\n"
- ".section .fixup,\"ax\"\n"
- "3: movl $-1,%[err]\n"
- " jmp 2b\n"
- ".previous\n"
- _ASM_EXTABLE(1b,3b)
- : [err] "=r" (err)
+ xstate_fault
: "D" (xstate), "a" (lmask), "d" (hmask), "0" (0)
: "memory"); /* memory required? */
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;
- u32 hmask = mask >> 32;
+void *get_xsave_addr(struct xsave_struct *xsave, int xstate);
+void setup_xstate_comp(void);
- asm volatile(".byte " REX_PREFIX "0x0f,0xae,0x27\n\t"
- : : "D" (fx), "m" (*fx), "a" (lmask), "d" (hmask)
- : "memory");
-}
-
-static inline void fpu_xsave(struct fpu *fpu)
-{
- /* This, however, we can work around by forcing the compiler to select
- an addressing mode that doesn't require extended registers. */
- alternative_input(
- ".byte " REX_PREFIX "0x0f,0xae,0x27",
- ".byte " REX_PREFIX "0x0f,0xae,0x37",
- X86_FEATURE_XSAVEOPT,
- [fx] "D" (&fpu->state->xsave), "a" (-1), "d" (-1) :
- "memory");
-}
#endif