diff --git a/libunwind/src/UnwindRegistersSave.S b/libunwind/src/UnwindRegistersSave.S index 58ffd1b9e1fb3..5534d1734b6ba 100644 --- a/libunwind/src/UnwindRegistersSave.S +++ b/libunwind/src/UnwindRegistersSave.S @@ -305,9 +305,21 @@ DEFINE_LIBUNWIND_FUNCTION(__unw_getcontext) mflr 0 std 0, PPC64_OFFS_SRR0(3) // store lr as ssr0 PPC64_STR(1) + PPC64_STR(4) // Save r4 first since it will be used for fixing r2. +#if defined(_AIX) + // The TOC register (r2) was changed by the glue code if unw_getcontext + // is called from a different module. Save the original TOC register + // in the context if this is the case. + mflr 4 + lwz 4, 0(4) // Get the first instruction at the return address. + xoris 0, 4, 0xe841 // Is it reloading the TOC register "ld 2,40(1)"? + cmplwi 0, 0x28 + bne 0, LnoR2Fix // No need to fix up r2 if it is not. + ld 2, 40(1) // Use the saved TOC register in the stack. +LnoR2Fix: +#endif PPC64_STR(2) PPC64_STR(3) - PPC64_STR(4) PPC64_STR(5) PPC64_STR(6) PPC64_STR(7) @@ -547,9 +559,21 @@ DEFINE_LIBUNWIND_FUNCTION(__unw_getcontext) mflr 0 stw 0, 0(3) // store lr as ssr0 stw 1, 12(3) + stw 4, 24(3) // Save r4 first since it will be used for fixing r2. +#if defined(_AIX) + // The TOC register (r2) was changed by the glue code if unw_getcontext + // is called from a different module. Save the original TOC register + // in the context if this is the case. + mflr 4 + lwz 4, 0(4) // Get the instruction at the return address. + xoris 0, 4, 0x8041 // Is it reloading the TOC register "ld 2,40(1)"? + cmplwi 0, 0x14 + bne 0, LnoR2Fix // No need to fix up r2 if it is not. + lwz 2, 20(1) // Use the saved TOC register in the stack. +LnoR2Fix: +#endif stw 2, 16(3) stw 3, 20(3) - stw 4, 24(3) stw 5, 28(3) stw 6, 32(3) stw 7, 36(3) diff --git a/libunwind/test/unw_resume.pass.cpp b/libunwind/test/unw_resume.pass.cpp index 76273e4a8ef0a..08e8d4edeaf29 100644 --- a/libunwind/test/unw_resume.pass.cpp +++ b/libunwind/test/unw_resume.pass.cpp @@ -10,9 +10,6 @@ // Ensure that unw_resume() resumes execution at the stack frame identified by // cursor. -// TODO: Investigate this failure on AIX system. -// XFAIL: target={{.*}}-aix{{.*}} - // TODO: Figure out why this fails with Memory Sanitizer. // XFAIL: msan