From 87ccc826bf1c9e5ab4c2f649b404e02c63e47622 Mon Sep 17 00:00:00 2001
From: Peter Zijlstra <peterz@infradead.org>
Date: Wed, 3 Feb 2021 12:02:21 +0100
Subject: 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>
---
tools/objtool/orc_dump.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
(limited to 'tools/objtool')
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
--
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