Change xsave_user() and xrestore_user() to avoid the (imho) horrible and should-die xstate_fault helper, they both can use __user_insn().
This also removes the "memory" clobber but I think it was never needed. xrestore_user() doesn't change the memory, it only changes the FPU regs. xsave_user() does write to "*buf" but this memory is "__user", we must never access it directly. This patch adds '"=m" (*buf)' in both cases, but this is only because currently __user_insn() needs the non-empty "output" arg. Note: I think we can change all other xstate_fault users too, including alternative_input's. Signed-off-by: Oleg Nesterov <[email protected]> --- arch/x86/include/asm/xsave.h | 19 +++++-------------- 1 files changed, 5 insertions(+), 14 deletions(-) diff --git a/arch/x86/include/asm/xsave.h b/arch/x86/include/asm/xsave.h index 5fa9770..441f171 100644 --- a/arch/x86/include/asm/xsave.h +++ b/arch/x86/include/asm/xsave.h @@ -229,12 +229,8 @@ static inline int xsave_user(struct xsave_struct __user *buf) if (unlikely(err)) return -EFAULT; - __asm__ __volatile__(ASM_STAC "\n" - "1:"XSAVE"\n" - "2: " ASM_CLAC "\n" - xstate_fault - : "D" (buf), "a" (-1), "d" (-1), "0" (0) - : "memory"); + err = __user_insn(XSAVE, "=m" (*buf), /* unneeded */ + "D" (buf), "a" (-1), "d" (-1)); return err; } @@ -243,17 +239,12 @@ static inline int xsave_user(struct xsave_struct __user *buf) */ static inline int xrestore_user(struct xsave_struct __user *buf, u64 mask) { - int err = 0; - struct xsave_struct *xstate = ((__force struct xsave_struct *)buf); u32 lmask = mask; u32 hmask = mask >> 32; + int err; - __asm__ __volatile__(ASM_STAC "\n" - "1:"XRSTOR"\n" - "2: " ASM_CLAC "\n" - xstate_fault - : "D" (xstate), "a" (lmask), "d" (hmask), "0" (0) - : "memory"); /* memory required? */ + err = __user_insn(XRSTOR, "=m" (*buf), /* unneeded */ + "D" (buf), "a" (lmask), "d" (hmask)); return err; } -- 1.5.5.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
