This is an archive of the discontinued LLVM Phabricator instance.

Differential D107042

[libunwind][OR1K] Fix register restore on resume
ClosedPublic

Authored by occheung on Jul 29 2021, 12:53 AM.

Details

Reviewers
whitequark
compnerd
Group Reviewers
Restricted Project
Commits
rGd6d0b6559e97: unwind: repair register restoration for OR1K
Summary

Currently, OR1K architecture put the program counter at offset 0x128 of the current or1k_thread_state_t. However, the PC is restored after updating the thread pointer in r3, which causes the PC to be fetched incorrectly.

This patch swaps the order of restoration of r9 and r3, such that the PC is restored to r9 using the current thread state.

Diff Detail

Event Timeline

occheung created this revision.Jul 29 2021, 12:53 AM
Herald added a reviewer: Restricted Project. · View Herald TranscriptJul 29 2021, 12:53 AM
Herald added a subscriber: libcxx-commits. · View Herald Transcript
occheung requested review of this revision.Jul 29 2021, 12:53 AM
Herald added a project: Restricted Project. · View Herald TranscriptJul 29 2021, 12:53 AM
Herald added a subscriber: llvm-commits. · View Herald Transcript
Harbormaster completed remote builds in B116892: Diff 362660.Jul 29 2021, 1:00 AM
whitequark accepted this revision.Jul 29 2021, 7:50 AM

LGTM

compnerd accepted this revision.Jul 29 2021, 1:17 PM
This revision is now accepted and ready to land.Jul 29 2021, 1:17 PM
occheung added a comment.Jul 29 2021, 6:49 PM

Thank you for the approval. I do not have commit access, please commit this patch for me.

Closed by commit rGd6d0b6559e97: unwind: repair register restoration for OR1K (authored by compnerd). · Explain WhyAug 2 2021, 9:40 AM
This revision was automatically updated to reflect the committed changes.
compnerd added a commit: rGd6d0b6559e97: unwind: repair register restoration for OR1K.

Revision Contents

PathSize
libunwind/
src/
5 lines

Diff 363501

libunwind/src/UnwindRegistersRestore.S

Show First 20 Lines • Show All 794 Lines • ▼ Show 20 Lines#
l.lwz r25,100(r3) l.lwz r25,100(r3)
l.lwz r26,104(r3) l.lwz r26,104(r3)
l.lwz r27,108(r3) l.lwz r27,108(r3)
l.lwz r28,112(r3) l.lwz r28,112(r3)
l.lwz r29,116(r3) l.lwz r29,116(r3)
l.lwz r30,120(r3) l.lwz r30,120(r3)
l.lwz r31,124(r3) l.lwz r31,124(r3)
# load new pc into ra
l.lwz r9, 128(r3)
# at last, restore r3 # at last, restore r3
l.lwz r3, 12(r3) l.lwz r3, 12(r3)
# load new pc into ra
l.lwz r9, 128(r3)
# jump to pc # jump to pc
l.jr r9 l.jr r9
l.nop l.nop
#elif defined(__hexagon__) #elif defined(__hexagon__)
# On entry: # On entry:
# thread_state pointer is in r2 # thread_state pointer is in r2
DEFINE_LIBUNWIND_FUNCTION(_ZN9libunwind17Registers_hexagon6jumptoEv) DEFINE_LIBUNWIND_FUNCTION(_ZN9libunwind17Registers_hexagon6jumptoEv)
▲ Show 20 Lines • Show All 346 Lines • Show Last 20 Lines