x86, xsave: context switch support using xsave/xrstor

[linux-2.6-omap-h63xx.git] / include / asm-x86 / xsave.h

diff --git a/include/asm-x86/xsave.h b/include/asm-x86/xsave.h
index 6d70e62c6bdc1a3c9878bd1cc6225b6a5265b58a..e835a917ee19c53165dc92be913217a176abc4d7 100644 (file)
--- 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