x86/fpu: Dont restore PKRU in fpregs_restore_userspace()

[linux-2.6-microblaze.git] / arch / x86 / include / asm / fpu / xstate.h

diff --git a/arch/x86/include/asm/fpu/xstate.h b/arch/x86/include/asm/fpu/xstate.h
index 47a9223..6a0aaaf 100644 (file)
--- a/arch/x86/include/asm/fpu/xstate.h
+++ b/arch/x86/include/asm/fpu/xstate.h
@@ -6,6 +6,7 @@
 #include <linux/types.h>
 
 #include <asm/processor.h>
+#include <asm/fpu/api.h>
 #include <asm/user.h>
 
 /* Bit 63 of XCR0 is reserved for future expansion */
@@ -34,6 +35,14 @@
                                      XFEATURE_MASK_BNDREGS | \
                                      XFEATURE_MASK_BNDCSR)
 
+/*
+ * Features which are restored when returning to user space.
+ * PKRU is not restored on return to user space because PKRU
+ * is switched eagerly in switch_to() and flush_thread()
+ */
+#define XFEATURE_MASK_USER_RESTORE     \
+       (XFEATURE_MASK_USER_SUPPORTED & ~XFEATURE_MASK_PKRU)
+
 /* All currently supported supervisor features */
 #define XFEATURE_MASK_SUPERVISOR_SUPPORTED (XFEATURE_MASK_PASID)
 
@@ -42,21 +51,21 @@
  * and its size may be huge. Saving/restoring such supervisor state components
  * at each context switch can cause high CPU and space overhead, which should
  * be avoided. Such supervisor state components should only be saved/restored
- * on demand. The on-demand dynamic supervisor features are set in this mask.
+ * on demand. The on-demand supervisor features are set in this mask.
  *
- * Unlike the existing supported supervisor features, a dynamic supervisor
+ * Unlike the existing supported supervisor features, an independent supervisor
  * feature does not allocate a buffer in task->fpu, and the corresponding
  * supervisor state component cannot be saved/restored at each context switch.
  *
- * To support a dynamic supervisor feature, a developer should follow the
+ * To support an independent supervisor feature, a developer should follow the
  * dos and don'ts as below:
  * - Do dynamically allocate a buffer for the supervisor state component.
  * - Do manually invoke the XSAVES/XRSTORS instruction to save/restore the
  *   state component to/from the buffer.
- * - Don't set the bit corresponding to the dynamic supervisor feature in
+ * - Don't set the bit corresponding to the independent supervisor feature in
  *   IA32_XSS at run time, since it has been set at boot time.
  */
-#define XFEATURE_MASK_DYNAMIC (XFEATURE_MASK_LBR)
+#define XFEATURE_MASK_INDEPENDENT (XFEATURE_MASK_LBR)
 
 /*
  * Unsupported supervisor features. When a supervisor feature in this mask is
@@ -66,7 +75,7 @@
 
 /* All supervisor states including supported and unsupported states. */
 #define XFEATURE_MASK_SUPERVISOR_ALL (XFEATURE_MASK_SUPERVISOR_SUPPORTED | \
-                                     XFEATURE_MASK_DYNAMIC | \
+                                     XFEATURE_MASK_INDEPENDENT | \
                                      XFEATURE_MASK_SUPERVISOR_UNSUPPORTED)
 
 #ifdef CONFIG_X86_64
@@ -82,17 +91,32 @@ static inline u64 xfeatures_mask_supervisor(void)
        return xfeatures_mask_all & XFEATURE_MASK_SUPERVISOR_SUPPORTED;
 }
 
-static inline u64 xfeatures_mask_user(void)
+/*
+ * The xfeatures which are enabled in XCR0 and expected to be in ptrace
+ * buffers and signal frames.
+ */
+static inline u64 xfeatures_mask_uabi(void)
 {
        return xfeatures_mask_all & XFEATURE_MASK_USER_SUPPORTED;
 }
 
-static inline u64 xfeatures_mask_dynamic(void)
+/*
+ * The xfeatures which are restored by the kernel when returning to user
+ * mode. This is not necessarily the same as xfeatures_mask_uabi() as the
+ * kernel does not manage all XCR0 enabled features via xsave/xrstor as
+ * some of them have to be switched eagerly on context switch and exec().
+ */
+static inline u64 xfeatures_mask_restore_user(void)
+{
+       return xfeatures_mask_all & XFEATURE_MASK_USER_RESTORE;
+}
+
+static inline u64 xfeatures_mask_independent(void)
 {
        if (!boot_cpu_has(X86_FEATURE_ARCH_LBR))
-               return XFEATURE_MASK_DYNAMIC & ~XFEATURE_MASK_LBR;
+               return XFEATURE_MASK_INDEPENDENT & ~XFEATURE_MASK_LBR;
 
-       return XFEATURE_MASK_DYNAMIC;
+       return XFEATURE_MASK_INDEPENDENT;
 }
 
 extern u64 xstate_fx_sw_bytes[USER_XSTATE_FX_SW_WORDS];
@@ -101,19 +125,21 @@ extern void __init update_regset_xstate_info(unsigned int size,
                                             u64 xstate_mask);
 
 void *get_xsave_addr(struct xregs_state *xsave, int xfeature_nr);
-const void *get_xsave_field_ptr(int xfeature_nr);
-int using_compacted_format(void);
 int xfeature_size(int xfeature_nr);
-struct membuf;
-void copy_xstate_to_kernel(struct membuf to, struct xregs_state *xsave);
-int copy_kernel_to_xstate(struct xregs_state *xsave, const void *kbuf);
-int copy_user_to_xstate(struct xregs_state *xsave, const void __user *ubuf);
-void copy_supervisor_to_kernel(struct xregs_state *xsave);
-void copy_dynamic_supervisor_to_kernel(struct xregs_state *xstate, u64 mask);
-void copy_kernel_to_dynamic_supervisor(struct xregs_state *xstate, u64 mask);
+int copy_uabi_from_kernel_to_xstate(struct xregs_state *xsave, const void *kbuf);
+int copy_sigframe_from_user_to_xstate(struct xregs_state *xsave, const void __user *ubuf);
+
+void xsaves(struct xregs_state *xsave, u64 mask);
+void xrstors(struct xregs_state *xsave, u64 mask);
 
+enum xstate_copy_mode {
+       XSTATE_COPY_FP,
+       XSTATE_COPY_FX,
+       XSTATE_COPY_XSAVE,
+};
 
-/* Validate an xstate header supplied by userspace (ptrace or sigreturn) */
-int validate_user_xstate_header(const struct xstate_header *hdr);
+struct membuf;
+void copy_xstate_to_uabi_buf(struct membuf to, struct xregs_state *xsave,
+                            enum xstate_copy_mode mode);
 
 #endif