[tip: x86/core] x86/xen: Remove .fixup usage

[tip-bot2 for Peter Zijlstra]

The following commit has been merged into the x86/core branch of tip:

Commit-ID:     e2b48e43284c0916ebf8e4240199b9d9747e337a
Gitweb:        https://git.kernel.org/tip/e2b48e43284c0916ebf8e4240199b9d9747e337a
Author:        Peter Zijlstra <peterz@xxxxxxxxxxxxx>
AuthorDate:    Wed, 10 Nov 2021 11:01:13 +01:00
Committer:     Peter Zijlstra <peterz@xxxxxxxxxxxxx>
CommitterDate: Sat, 11 Dec 2021 09:09:48 +01:00

x86/xen: Remove .fixup usage

Employ the fancy new EX_TYPE_IMM_REG to store -EFAULT in the return
register and use this to remove some Xen .fixup usage.

All callers of these functions only test for 0 return, so the actual
return value change from -1 to -EFAULT is immaterial.

Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Reviewed-by: Juergen Gross <jgross@xxxxxxxx>
Reviewed-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20211110101325.545019822@xxxxxxxxxxxxx
---
 arch/x86/include/asm/xen/page.h | 14 +++-----------
 1 file changed, 3 insertions(+), 11 deletions(-)

diff --git a/arch/x86/include/asm/xen/page.h b/arch/x86/include/asm/xen/page.h
index 1a162e5..e989bc2 100644
--- a/arch/x86/include/asm/xen/page.h
+++ b/arch/x86/include/asm/xen/page.h
@@ -96,11 +96,7 @@ static inline int xen_safe_write_ulong(unsigned long *addr, unsigned long val)
 
 	asm volatile("1: mov %[val], %[ptr]\n"
 		     "2:\n"
-		     ".section .fixup, \"ax\"\n"
-		     "3: sub $1, %[ret]\n"
-		     "   jmp 2b\n"
-		     ".previous\n"
-		     _ASM_EXTABLE(1b, 3b)
+		     _ASM_EXTABLE_TYPE_REG(1b, 2b, EX_TYPE_EFAULT_REG, %[ret])
 		     : [ret] "+r" (ret), [ptr] "=m" (*addr)
 		     : [val] "r" (val));
 
@@ -110,16 +106,12 @@ static inline int xen_safe_write_ulong(unsigned long *addr, unsigned long val)
 static inline int xen_safe_read_ulong(const unsigned long *addr,
 				      unsigned long *val)
 {
-	int ret = 0;
 	unsigned long rval = ~0ul;
+	int ret = 0;
 
 	asm volatile("1: mov %[ptr], %[rval]\n"
 		     "2:\n"
-		     ".section .fixup, \"ax\"\n"
-		     "3: sub $1, %[ret]\n"
-		     "   jmp 2b\n"
-		     ".previous\n"
-		     _ASM_EXTABLE(1b, 3b)
+		     _ASM_EXTABLE_TYPE_REG(1b, 2b, EX_TYPE_EFAULT_REG, %[ret])
 		     : [ret] "+r" (ret), [rval] "+r" (rval)
 		     : [ptr] "m" (*addr));
 	*val = rval;