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

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);