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| author | Kewen Lin <linkw@linux.ibm.com> | 2023-03-08 00:57:21 -0600 |
|---|---|---|
| committer | Kewen Lin <linkw@linux.ibm.com> | 2023-03-08 00:57:21 -0600 |
| commit | 15b83b69ca99d97643075776ba94f2dd1f05b46e (patch) | |
| tree | 38356a5d8d2b0fd08fbfe8ab77ce8b003ed3e1c8 /libgcc | |
| parent | 2a2a159f7bd9d929ce457937f669ed2dd6ebccec (diff) | |
| download | gcc-15b83b69ca99d97643075776ba94f2dd1f05b46e.zip gcc-15b83b69ca99d97643075776ba94f2dd1f05b46e.tar.gz gcc-15b83b69ca99d97643075776ba94f2dd1f05b46e.tar.bz2 | |
libgcc, rs6000: Fix bump size for powerpc64 elfv1 ABI [PR108727]
As PR108727 shows, when cleanup code called by the stack
unwinder calls function _Unwind_Resume, it goes via plt
stub like:
function 00000000.plt_call._Unwind_Resume:
=> 0x0000000010003580 <+0>: std r2,40(r1)
0x0000000010003584 <+4>: ld r12,-31760(r2)
0x0000000010003588 <+8>: mtctr r12
0x000000001000358c <+12>: ld r2,-31752(r2)
0x0000000010003590 <+16>: cmpldi r2,0
0x0000000010003594 <+20>: bnectr+
0x0000000010003598 <+24>: b 0x100031a4
<_Unwind_Resume@plt>
It wants to save TOC base (r2) to r1 + 40, but we only
bump the stack segment by 32 bytes as follows:
stdu %r29,-32(%r3)
It means the access is out of the stack segment allocated
by __generic_morestack, once the touch area isn't writable
like this failure shows, it would cause segment fault.
So fix the bump size with one reasonable value PARAMS.
PR libgcc/108727
libgcc/ChangeLog:
* config/rs6000/morestack.S (__morestack): Use PARAMS for new stack
bump size.
Diffstat (limited to 'libgcc')
| -rw-r--r-- | libgcc/config/rs6000/morestack.S | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/libgcc/config/rs6000/morestack.S b/libgcc/config/rs6000/morestack.S index 5e7ad13..f2fea6a 100644 --- a/libgcc/config/rs6000/morestack.S +++ b/libgcc/config/rs6000/morestack.S @@ -205,12 +205,12 @@ ENTRY0(__morestack) bl JUMP_TARGET(__generic_morestack) # Start using new stack - stdu %r29,-32(%r3) # back-chain + stdu %r29,-PARAMS(%r3) # back-chain mr %r1,%r3 # Set __private_ss stack guard for the new stack. ld %r12,NEWSTACKSIZE_SAVE(%r29) # modified size - addi %r3,%r3,BACKOFF-32 + addi %r3,%r3,BACKOFF-PARAMS sub %r3,%r3,%r12 # Note that a signal frame has $pc pointing at the instruction # where the signal occurred. For something like a timer |