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x86/xen: Remove .fixup usage

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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
This commit is contained in:
Peter Zijlstra 2021-11-10 11:01:13 +01:00
parent 99641e094d
commit e2b48e4328
1 changed files with 3 additions and 11 deletions
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14
arch/x86/include/asm/xen/page.h
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@ -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;