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unwind: repair register restoration for OR1K 

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.

Patch by Oi Chee Cheung!

Reviewed By: whitequark, compnerd

Differential Revision: https://reviews.llvm.org/D107042
This commit is contained in:
Saleem Abdulrasool 2021-08-02 16:34:56 +00:00
parent 9e02f58780
commit d6d0b6559e
1 changed files with 3 additions and 2 deletions
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5
libunwind/src/UnwindRegistersRestore.S
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@ -800,11 +800,12 @@ DEFINE_LIBUNWIND_FUNCTION(_ZN9libunwind14Registers_or1k6jumptoEv)
l.lwz r30,120(r3)
l.lwz r31,124(r3)
# load new pc into ra
l.lwz r9, 128(r3)
# at last, restore r3
l.lwz r3, 12(r3)
# load new pc into ra
l.lwz r9, 128(r3)
# jump to pc
l.jr r9
l.nop