glibc/sysdeps/powerpc/ifunc-sel.h
Nick Alcock de6591238b Do not stack-protect ifunc resolvers [BZ #7065]
When dynamically linking, ifunc resolvers are called before TLS is
initialized, so they cannot be safely stack-protected.

We avoid disabling stack-protection on large numbers of files by
using __attribute__ ((__optimize__ ("-fno-stack-protector")))
to turn it off just for the resolvers themselves.  (We provide
the attribute even when statically linking, because we will later
use it elsewhere too.)
2016-12-26 10:08:41 +01:00

52 lines
1.1 KiB
C

/* Used by the elf ifunc tests. */
#ifndef ELF_IFUNC_SEL_H
#define ELF_IFUNC_SEL_H 1
extern int global;
static inline void *
inhibit_stack_protector
ifunc_sel (int (*f1) (void), int (*f2) (void), int (*f3) (void))
{
register void *ret __asm__ ("r3");
__asm__ ("mflr 12\n\t"
"bcl 20,31,1f\n"
"1:\tmflr 11\n\t"
"mtlr 12\n\t"
"addis 12,11,global-1b@ha\n\t"
"lwz 12,global-1b@l(12)\n\t"
"addis %0,11,%2-1b@ha\n\t"
"addi %0,%0,%2-1b@l\n\t"
"cmpwi 12,1\n\t"
"beq 2f\n\t"
"addis %0,11,%3-1b@ha\n\t"
"addi %0,%0,%3-1b@l\n\t"
"cmpwi 12,-1\n\t"
"beq 2f\n\t"
"addis %0,11,%4-1b@ha\n\t"
"addi %0,%0,%4-1b@l\n\t"
"2:"
: "=r" (ret)
: "i" (&global), "i" (f1), "i" (f2), "i" (f3)
: "11", "12", "cr0");
return ret;
}
static inline void *
inhibit_stack_protector
ifunc_one (int (*f1) (void))
{
register void *ret __asm__ ("r3");
__asm__ ("mflr 12\n\t"
"bcl 20,31,1f\n"
"1:\tmflr %0\n\t"
"mtlr 12\n\t"
"addis %0,%0,%1-1b@ha\n\t"
"addi %0,%0,%1-1b@l"
: "=r" (ret)
: "i" (f1)
: "12");
return ret;
}
#endif