x86, xsave: enable xsave/xrstor on cpus with xsave support

Enables xsave/xrstor by turning on cr4.osxsave on cpu's which have
the xsave support. For now, features that OS supports/enabled are
FP and SSE.

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

4 files changed, 40 insertions, 0 deletions

diff --git a/include/asm-x86/i387.h b/include/asm-x86/i387.h
index 3958de6aad0e..6a6647896670 100644
--- a/include/asm-x86/i387.h
+++ b/include/asm-x86/i387.h
@@ -18,6 +18,7 @@
 #include <asm/sigcontext.h>
 #include <asm/user.h>
 #include <asm/uaccess.h>
+#include <asm/xsave.h>
 
 extern void fpu_init(void);
 extern void mxcsr_feature_mask_init(void);
diff --git a/include/asm-x86/processor-flags.h b/include/asm-x86/processor-flags.h
index 5dd79774f693..dc5f0712f9fa 100644
--- a/include/asm-x86/processor-flags.h
+++ b/include/asm-x86/processor-flags.h
@@ -59,6 +59,7 @@
 #define X86_CR4_OSFXSR  0x00000200 /* enable fast FPU save and restore */
 #define X86_CR4_OSXMMEXCPT 0x00000400 /* enable unmasked SSE exceptions */
 #define X86_CR4_VMXE    0x00002000 /* enable VMX virtualization */
+#define X86_CR4_OSXSAVE 0x00040000 /* enable xsave and xrestore */
 
 /*
  * x86-64 Task Priority Register, CR8
diff --git a/include/asm-x86/processor.h b/include/asm-x86/processor.h
index d60b4d81febe..d7c0221c0278 100644
--- a/include/asm-x86/processor.h
+++ b/include/asm-x86/processor.h
@@ -346,6 +346,18 @@ struct i387_soft_struct {
         u32                     entry_eip;
 };
 
+struct xsave_hdr_struct {
+        u64 xstate_bv;
+        u64 reserved1[2];
+        u64 reserved2[5];
+} __attribute__((packed));
+
+struct xsave_struct {
+        struct i387_fxsave_struct i387;
+        struct xsave_hdr_struct xsave_hdr;
+        /* new processor state extensions will go here */
+} __attribute__ ((packed, aligned (64)));
+
 union thread_xstate {
         struct i387_fsave_struct        fsave;
         struct i387_fxsave_struct       fxsave;
diff --git a/include/asm-x86/xsave.h b/include/asm-x86/xsave.h
new file mode 100644
index 000000000000..6d70e62c6bdc
--- /dev/null
+++ b/include/asm-x86/xsave.h
@@ -0,0 +1,26 @@
+#ifndef __ASM_X86_XSAVE_H
+#define __ASM_X86_XSAVE_H
+
+#include <asm/processor.h>
+#include <asm/i387.h>
+
+#define XSTATE_FP       0x1
+#define XSTATE_SSE      0x2
+
+#define XSTATE_FPSSE    (XSTATE_FP | XSTATE_SSE)
+
+#define FXSAVE_SIZE     512
+
+/*
+ * These are the features that the OS can handle currently.
+ */
+#define XCNTXT_LMASK    (XSTATE_FP | XSTATE_SSE)
+#define XCNTXT_HMASK    0x0
+
+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);
+
+#endif