Commit e2b48e43 authored by Peter Zijlstra's avatar Peter Zijlstra
Browse files

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: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: default avatarJuergen Gross <jgross@suse.com>
Reviewed-by: default avatarJosh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20211110101325.545019822@infradead.org
parent 99641e09

arch/x86/include/asm/xen/page.h

+3 −11
Original line number Diff line number Diff line
@@ -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;