From: Saleem Abdulrasool <compnerd@compnerd.org>
Date: Mon, 2 Aug 2021 16:34:56 +0000 (+0000)
Subject: unwind: repair register restoration for OR1K
X-Git-Tag: upstream/15.0.7~34915
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=d6d0b6559e97a3d0b258814e870d3e19f3a7ffcc;p=platform%2Fupstream%2Fllvm.git

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
---

diff --git a/libunwind/src/UnwindRegistersRestore.S b/libunwind/src/UnwindRegistersRestore.S
index d8bf1ad..c2106f3 100644
--- a/libunwind/src/UnwindRegistersRestore.S
+++ b/libunwind/src/UnwindRegistersRestore.S
@@ -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