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authorLinus Torvalds <torvalds@linux-foundation.org>2016-01-11 16:56:38 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2016-01-11 16:56:38 -0800
commit6896d9f7e7ee98d772224a539b7581a1e6dd6b2c (patch)
treea9c491e55e36437fbe1d358f7cd5f6db222fd1d6 /arch
parent671d5532aaad777782b66eff71bc4dfad25f942d (diff)
parente49a449b869afb2b8bf282427c8355bc3a2fad56 (diff)
Merge branch 'x86-fpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fpu updates from Ingo Molnar: "This cleans up the FPU fault handling methods to be more robust, and moves eligible variables to .init.data" * 'x86-fpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/fpu: Put a few variables in .init.data x86/fpu: Get rid of xstate_fault() x86/fpu: Add an XSTATE_OP() macro
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/include/asm/fpu/internal.h173
-rw-r--r--arch/x86/kernel/fpu/init.c4
-rw-r--r--arch/x86/kernel/fpu/xstate.c4
3 files changed, 87 insertions, 94 deletions
diff --git a/arch/x86/include/asm/fpu/internal.h b/arch/x86/include/asm/fpu/internal.h
index 3c3550c3a4a3..eadcdd5bb946 100644
--- a/arch/x86/include/asm/fpu/internal.h
+++ b/arch/x86/include/asm/fpu/internal.h
@@ -224,18 +224,67 @@ static inline void copy_fxregs_to_kernel(struct fpu *fpu)
#define XRSTOR ".byte " REX_PREFIX "0x0f,0xae,0x2f"
#define XRSTORS ".byte " REX_PREFIX "0x0f,0xc7,0x1f"
-/* xstate instruction fault handler: */
-#define xstate_fault(__err) \
- \
- ".section .fixup,\"ax\"\n" \
- \
- "3: movl $-2,%[_err]\n" \
- " jmp 2b\n" \
- \
- ".previous\n" \
- \
- _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")
+
+/*
+ * If XSAVES is enabled, it replaces XSAVEOPT because it supports a 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.
+ *
+ * We use XSAVE as a fallback.
+ *
+ * The 661 label is defined in the ALTERNATIVE* macros as the address of the
+ * original instruction which gets replaced. We need to use it here as the
+ * address of the instruction where we might get an exception at.
+ */
+#define XSTATE_XSAVE(st, lmask, hmask, err) \
+ asm volatile(ALTERNATIVE_2(XSAVE, \
+ XSAVEOPT, X86_FEATURE_XSAVEOPT, \
+ XSAVES, X86_FEATURE_XSAVES) \
+ "\n" \
+ "xor %[err], %[err]\n" \
+ "3:\n" \
+ ".pushsection .fixup,\"ax\"\n" \
+ "4: movl $-2, %[err]\n" \
+ "jmp 3b\n" \
+ ".popsection\n" \
+ _ASM_EXTABLE(661b, 4b) \
+ : [err] "=r" (err) \
+ : "D" (st), "m" (*st), "a" (lmask), "d" (hmask) \
+ : "memory")
+
+/*
+ * Use XRSTORS to restore context if it is enabled. XRSTORS supports compact
+ * XSAVE area format.
+ */
+#define XSTATE_XRESTORE(st, lmask, hmask, err) \
+ asm volatile(ALTERNATIVE(XRSTOR, \
+ XRSTORS, X86_FEATURE_XSAVES) \
+ "\n" \
+ "xor %[err], %[err]\n" \
+ "3:\n" \
+ ".pushsection .fixup,\"ax\"\n" \
+ "4: movl $-2, %[err]\n" \
+ "jmp 3b\n" \
+ ".popsection\n" \
+ _ASM_EXTABLE(661b, 4b) \
+ : [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
@@ -246,22 +295,14 @@ 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 +317,14 @@ 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);
@@ -305,33 +338,11 @@ static inline void copy_xregs_to_kernel(struct xregs_state *xstate)
u64 mask = -1;
u32 lmask = mask;
u32 hmask = mask >> 32;
- int err = 0;
+ int err;
WARN_ON(!alternatives_patched);
- /*
- * 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,
- XSAVEOPT,
- X86_FEATURE_XSAVEOPT,
- XSAVES,
- X86_FEATURE_XSAVES,
- [xstate] "D" (xstate), "a" (lmask), "d" (hmask) :
- "memory");
- asm volatile("2:\n\t"
- xstate_fault(err)
- : "0" (err)
- : "memory");
+ XSTATE_XSAVE(xstate, lmask, hmask, err);
/* We should never fault when copying to a kernel buffer: */
WARN_ON_FPU(err);
@@ -344,23 +355,9 @@ static inline void copy_kernel_to_xregs(struct xregs_state *xstate, u64 mask)
{
u32 lmask = mask;
u32 hmask = mask >> 32;
- int err = 0;
+ int err;
- /*
- * 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,
- XRSTORS,
- X86_FEATURE_XSAVES,
- "D" (xstate), "m" (*xstate), "a" (lmask), "d" (hmask)
- : "memory");
-
- asm volatile("2:\n"
- xstate_fault(err)
- : "0" (err)
- : "memory");
+ XSTATE_XRESTORE(xstate, lmask, hmask, err);
/* We should never fault when copying from a kernel buffer: */
WARN_ON_FPU(err);
@@ -388,12 +385,10 @@ 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 +400,12 @@ 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;
-
- __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? */
+ int err;
+
+ stac();
+ XSTATE_OP(XRSTOR, xstate, lmask, hmask, err);
+ clac();
+
return err;
}
diff --git a/arch/x86/kernel/fpu/init.c b/arch/x86/kernel/fpu/init.c
index 0d4e092ae1bf..7b2978ab30df 100644
--- a/arch/x86/kernel/fpu/init.c
+++ b/arch/x86/kernel/fpu/init.c
@@ -197,7 +197,7 @@ static void __init fpu__init_task_struct_size(void)
*/
static void __init fpu__init_system_xstate_size_legacy(void)
{
- static int on_boot_cpu = 1;
+ static int on_boot_cpu __initdata = 1;
WARN_ON_FPU(!on_boot_cpu);
on_boot_cpu = 0;
@@ -287,7 +287,7 @@ __setup("eagerfpu=", eager_fpu_setup);
*/
static void __init fpu__init_system_ctx_switch(void)
{
- static bool on_boot_cpu = 1;
+ static bool on_boot_cpu __initdata = 1;
WARN_ON_FPU(!on_boot_cpu);
on_boot_cpu = 0;
diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c
index 70fc312221fc..40f100285984 100644
--- a/arch/x86/kernel/fpu/xstate.c
+++ b/arch/x86/kernel/fpu/xstate.c
@@ -297,7 +297,7 @@ static void __init setup_xstate_comp(void)
*/
static void __init setup_init_fpu_buf(void)
{
- static int on_boot_cpu = 1;
+ static int on_boot_cpu __initdata = 1;
WARN_ON_FPU(!on_boot_cpu);
on_boot_cpu = 0;
@@ -608,7 +608,7 @@ static void fpu__init_disable_system_xstate(void)
void __init fpu__init_system_xstate(void)
{
unsigned int eax, ebx, ecx, edx;
- static int on_boot_cpu = 1;
+ static int on_boot_cpu __initdata = 1;
int err;
WARN_ON_FPU(!on_boot_cpu);