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authorPeter Zijlstra <peterz@infradead.org>2020-08-18 15:57:49 +0200
committerIngo Molnar <mingo@kernel.org>2020-09-01 09:58:06 +0200
commit5b06fd3bb9cdce4f3e731c48eb5b74c4acc47997 (patch)
tree533fcad5bdd98fd31ccd3956dec2e3478f15ca91 /tools/objtool
parent452cddbff74b6a15b9354505671011700fe03710 (diff)
downloadlinux-5b06fd3bb9cdce4f3e731c48eb5b74c4acc47997.tar.bz2
static_call: Handle tail-calls
GCC can turn our static_call(name)(args...) into a tail call, in which case we get a JMP.d32 into the trampoline (which then does a further tail-call). Teach objtool to recognise and mark these in .static_call_sites and adjust the code patching to deal with this. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: https://lore.kernel.org/r/20200818135805.101186767@infradead.org
Diffstat (limited to 'tools/objtool')
-rw-r--r--tools/objtool/check.c18
1 files changed, 13 insertions, 5 deletions
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index f8f7a40c6ef3..75d0cd2f9044 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -516,7 +516,7 @@ static int create_static_call_sections(struct objtool_file *file)
}
memset(reloc, 0, sizeof(*reloc));
reloc->sym = key_sym;
- reloc->addend = 0;
+ reloc->addend = is_sibling_call(insn) ? STATIC_CALL_SITE_TAIL : 0;
reloc->type = R_X86_64_PC32;
reloc->offset = idx * sizeof(struct static_call_site) + 4;
reloc->sec = reloc_sec;
@@ -747,6 +747,10 @@ static int add_jump_destinations(struct objtool_file *file)
} else {
/* external sibling call */
insn->call_dest = reloc->sym;
+ if (insn->call_dest->static_call_tramp) {
+ list_add_tail(&insn->static_call_node,
+ &file->static_call_list);
+ }
continue;
}
@@ -798,6 +802,10 @@ static int add_jump_destinations(struct objtool_file *file)
/* internal sibling call */
insn->call_dest = insn->jump_dest->func;
+ if (insn->call_dest->static_call_tramp) {
+ list_add_tail(&insn->static_call_node,
+ &file->static_call_list);
+ }
}
}
}
@@ -1684,6 +1692,10 @@ static int decode_sections(struct objtool_file *file)
if (ret)
return ret;
+ ret = read_static_call_tramps(file);
+ if (ret)
+ return ret;
+
ret = add_jump_destinations(file);
if (ret)
return ret;
@@ -1716,10 +1728,6 @@ static int decode_sections(struct objtool_file *file)
if (ret)
return ret;
- ret = read_static_call_tramps(file);
- if (ret)
- return ret;
-
return 0;
}