The following commit has been merged into the objtool/core branch of tip: Commit-ID: 87ccc826bf1c9e5ab4c2f649b404e02c63e47622 Gitweb: https://git.kernel.org/tip/87ccc826bf1c9e5ab4c2f649b404e02c63e47622 Author: Peter Zijlstra <[email protected]> AuthorDate: Wed, 03 Feb 2021 12:02:21 +01:00 Committer: Peter Zijlstra <[email protected]> CommitterDate: Wed, 10 Feb 2021 20:53:51 +01:00
x86/unwind/orc: Change REG_SP_INDIRECT Currently REG_SP_INDIRECT is unused but means (%rsp + offset), change it to mean (%rsp) + offset. The reason is that we're going to swizzle stack in the middle of a C function with non-trivial stack footprint. This means that when the unwinder finds the ToS, it needs to dereference it (%rsp) and then add the offset to the next frame, resulting in: (%rsp) + offset This is somewhat unfortunate, since REG_BP_INDIRECT is used (by DRAP) and thus needs to retain the current (%rbp + offset). Signed-off-by: Peter Zijlstra (Intel) <[email protected]> Reviewed-by: Miroslav Benes <[email protected]> Acked-by: Josh Poimboeuf <[email protected]> --- arch/x86/kernel/unwind_orc.c | 5 ++++- tools/objtool/orc_dump.c | 2 +- 2 files changed, 5 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/unwind_orc.c b/arch/x86/kernel/unwind_orc.c index 73f8001..2a1d47f 100644 --- a/arch/x86/kernel/unwind_orc.c +++ b/arch/x86/kernel/unwind_orc.c @@ -471,7 +471,7 @@ bool unwind_next_frame(struct unwind_state *state) break; case ORC_REG_SP_INDIRECT: - sp = state->sp + orc->sp_offset; + sp = state->sp; indirect = true; break; @@ -521,6 +521,9 @@ bool unwind_next_frame(struct unwind_state *state) if (indirect) { if (!deref_stack_reg(state, sp, &sp)) goto err; + + if (orc->sp_reg == ORC_REG_SP_INDIRECT) + sp += orc->sp_offset; } /* Find IP, SP and possibly regs: */ diff --git a/tools/objtool/orc_dump.c b/tools/objtool/orc_dump.c index c53fae9..f5a8508 100644 --- a/tools/objtool/orc_dump.c +++ b/tools/objtool/orc_dump.c @@ -55,7 +55,7 @@ static void print_reg(unsigned int reg, int offset) if (reg == ORC_REG_BP_INDIRECT) printf("(bp%+d)", offset); else if (reg == ORC_REG_SP_INDIRECT) - printf("(sp%+d)", offset); + printf("(sp)%+d", offset); else if (reg == ORC_REG_UNDEFINED) printf("(und)"); else
