diff options
| author | Josh Poimboeuf <jpoimboe@kernel.org> | 2025-04-08 00:02:14 -0700 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2025-04-08 09:14:11 +0200 |
| commit | fe1042b1ef79e4d5df33d5c0f0ce936493714eec (patch) | |
| tree | 30710f1b8faf6c8849840d13f1c88f0f68d42f9f /tools/objtool/check.c | |
| parent | a8df7d0ef92eca28c610206c6748daf537ac0586 (diff) | |
objtool: Split INSN_CONTEXT_SWITCH into INSN_SYSCALL and INSN_SYSRET
INSN_CONTEXT_SWITCH is ambiguous. It can represent both call semantics
(SYSCALL, SYSENTER) and return semantics (SYSRET, IRET, RETS, RETU).
Those differ significantly: calls preserve control flow whereas returns
terminate it.
Objtool uses an arbitrary rule for INSN_CONTEXT_SWITCH that almost works
by accident: if in a function, keep going; otherwise stop. It should
instead be based on the semantics of the underlying instruction.
In preparation for improving that, split INSN_CONTEXT_SWITCH into
INSN_SYCALL and INSN_SYSRET.
No functional change.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/19a76c74d2c051d3bc9a775823cafc65ad267a7a.1744095216.git.jpoimboe@kernel.org
Diffstat (limited to 'tools/objtool/check.c')
| -rw-r--r-- | tools/objtool/check.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/tools/objtool/check.c b/tools/objtool/check.c index c81b070ca495..2c703b960420 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -3684,7 +3684,8 @@ static int validate_branch(struct objtool_file *file, struct symbol *func, break; - case INSN_CONTEXT_SWITCH: + case INSN_SYSCALL: + case INSN_SYSRET: if (func) { if (!next_insn || !next_insn->hint) { WARN_INSN(insn, "unsupported instruction in callable function"); @@ -3886,7 +3887,8 @@ static int validate_unret(struct objtool_file *file, struct instruction *insn) WARN_INSN(insn, "RET before UNTRAIN"); return 1; - case INSN_CONTEXT_SWITCH: + case INSN_SYSCALL: + case INSN_SYSRET: if (insn_func(insn)) break; return 0; |