Messages in this thread | | | Date | Wed, 10 Nov 2021 12:00:39 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH v2 11/23] x86,xen: Remove .fixup usage |
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On Wed, Nov 10, 2021 at 11:35:37AM +0100, Juergen Gross wrote: > On 10.11.21 11:01, Peter Zijlstra wrote: > > 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> > > --- > > arch/x86/include/asm/xen/page.h | 14 +++----------- > > 1 file changed, 3 insertions(+), 11 deletions(-) > > > > --- 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(u > > 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(u > > static inline int xen_safe_read_ulong(const unsigned long *addr, > > unsigned long *val) > > { > > - int ret = 0; > > unsigned long rval = ~0ul; > > + int ret = 0; > > Spurious change.
Yeah, can't help myself, must be reverse xmas tree :-)
> > 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_EFAUL_REG, %[ret]) > > I guess you didn't compile that? There is a typo: s/EFAUL/EFAULT/
Damn.. I figure that must've gotten lost in the robot spam telling me clang can't do __cold on labels :/
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