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Subject[tip: x86/core] x86/xen: Remove .fixup usage
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@infradead.org>
AuthorDate: Wed, 10 Nov 2021 11:01:13 +01:00
Committer: Peter Zijlstra <peterz@infradead.org>
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@infradead.org>
Reviewed-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20211110101325.545019822@infradead.org
---
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;
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