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author | Josh Poimboeuf <jpoimboe@redhat.com> | 2021-01-21 15:29:22 -0600 |
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committer | Josh Poimboeuf <jpoimboe@redhat.com> | 2021-01-26 11:12:00 -0600 |
commit | ecf11ba4d066fe527586c6edd6ca68457ca55cf4 (patch) | |
tree | ee3fb4bffbc2cf2735b4cba2d3cc14972cff3a6e /tools | |
parent | 18660698a3d30868524cefb60dcd4e0e297f71bb (diff) | |
download | linux-stable-ecf11ba4d066fe527586c6edd6ca68457ca55cf4.tar.gz linux-stable-ecf11ba4d066fe527586c6edd6ca68457ca55cf4.tar.bz2 linux-stable-ecf11ba4d066fe527586c6edd6ca68457ca55cf4.zip |
objtool: Assume only ELF functions do sibling calls
There's an inconsistency in how sibling calls are detected in
non-function asm code, depending on the scope of the object. If the
target code is external to the object, objtool considers it a sibling
call. If the target code is internal but not a function, objtool
*doesn't* consider it a sibling call.
This can cause some inconsistencies between per-object and vmlinux.o
validation.
Instead, assume only ELF functions can do sibling calls. This generally
matches existing reality, and makes sibling call validation consistent
between vmlinux.o and per-object.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/0e9ab6f3628cc7bf3bde7aa6762d54d7df19ad78.1611263461.git.jpoimboe@redhat.com
Diffstat (limited to 'tools')
-rw-r--r-- | tools/objtool/check.c | 36 |
1 files changed, 22 insertions, 14 deletions
diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 5f5949951ca7..b4e1655017de 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -110,15 +110,20 @@ static struct instruction *prev_insn_same_sym(struct objtool_file *file, static bool is_sibling_call(struct instruction *insn) { + /* + * Assume only ELF functions can make sibling calls. This ensures + * sibling call detection consistency between vmlinux.o and individual + * objects. + */ + if (!insn->func) + return false; + /* An indirect jump is either a sibling call or a jump to a table. */ if (insn->type == INSN_JUMP_DYNAMIC) return list_empty(&insn->alts); - if (!is_static_jump(insn)) - return false; - /* add_jump_destinations() sets insn->call_dest for sibling calls. */ - return !!insn->call_dest; + return (is_static_jump(insn) && insn->call_dest); } /* @@ -774,7 +779,7 @@ static int add_jump_destinations(struct objtool_file *file) continue; reloc = find_reloc_by_dest_range(file->elf, insn->sec, - insn->offset, insn->len); + insn->offset, insn->len); if (!reloc) { dest_sec = insn->sec; dest_off = arch_jump_destination(insn); @@ -794,18 +799,21 @@ static int add_jump_destinations(struct objtool_file *file) insn->retpoline_safe = true; continue; - } else if (reloc->sym->sec->idx) { - dest_sec = reloc->sym->sec; - dest_off = reloc->sym->sym.st_value + - arch_dest_reloc_offset(reloc->addend); - } else { - /* external sibling call */ + } else if (insn->func) { + /* internal or external sibling call (with reloc) */ insn->call_dest = reloc->sym; if (insn->call_dest->static_call_tramp) { list_add_tail(&insn->static_call_node, &file->static_call_list); } continue; + } else if (reloc->sym->sec->idx) { + dest_sec = reloc->sym->sec; + dest_off = reloc->sym->sym.st_value + + arch_dest_reloc_offset(reloc->addend); + } else { + /* non-func asm code jumping to another file */ + continue; } insn->jump_dest = find_insn(file, dest_sec, dest_off); @@ -854,7 +862,7 @@ static int add_jump_destinations(struct objtool_file *file) } else if (insn->jump_dest->func->pfunc != insn->func->pfunc && insn->jump_dest->offset == insn->jump_dest->func->offset) { - /* internal sibling call */ + /* internal sibling call (without reloc) */ insn->call_dest = insn->jump_dest->func; if (insn->call_dest->static_call_tramp) { list_add_tail(&insn->static_call_node, @@ -2587,7 +2595,7 @@ static int validate_branch(struct objtool_file *file, struct symbol *func, case INSN_JUMP_CONDITIONAL: case INSN_JUMP_UNCONDITIONAL: - if (func && is_sibling_call(insn)) { + if (is_sibling_call(insn)) { ret = validate_sibling_call(insn, &state); if (ret) return ret; @@ -2609,7 +2617,7 @@ static int validate_branch(struct objtool_file *file, struct symbol *func, case INSN_JUMP_DYNAMIC: case INSN_JUMP_DYNAMIC_CONDITIONAL: - if (func && is_sibling_call(insn)) { + if (is_sibling_call(insn)) { ret = validate_sibling_call(insn, &state); if (ret) return ret; |