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| author | Peter Zijlstra <peterz@infradead.org> | 2021-02-03 12:02:21 +0100 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2021-02-10 20:53:51 +0100 |
| commit | 87ccc826bf1c9e5ab4c2f649b404e02c63e47622 (patch) | |
| tree | e38d55a0877be33672867af408ecc512d44493ee | |
| parent | 9077c016a39c78054f03e0354ad8409b47af68dc (diff) | |
| download | linux-87ccc826bf1c9e5ab4c2f649b404e02c63e47622.tar.bz2 | |
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) <peterz@infradead.org>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
| -rw-r--r-- | arch/x86/kernel/unwind_orc.c | 5 | ||||
| -rw-r--r-- | 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 73f800100066..2a1d47f47eee 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 c53fae9dbe93..f5a8508c42d6 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 |