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From: Julien Thierry <jthierry@redhat.com>
To: linux-kernel@vger.kernel.org
Cc: jpoimboe@redhat.com, peterz@infradead.org, raphael.gault@arm.com,
	Julien Thierry <jthierry@redhat.com>
Subject: [PATCH 05/10] objtool: check: Remove check preventing branches within alternative
Date: Wed, 25 Mar 2020 08:41:58 +0000	[thread overview]
Message-ID: <20200325084203.17005-6-jthierry@redhat.com> (raw)
In-Reply-To: <20200325084203.17005-1-jthierry@redhat.com>

While jumping from outside an alternative region to the middle of an
alternative region is very likely wrong, jumping from an alternative
region into the same region is valid. It is a common pattern on arm64.

The first pattern is unlikely to happen in practice and checking only
for this adds a lot of complexity.

Just remove the current check.

Suggested-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Julien Thierry <jthierry@redhat.com>
---
 tools/objtool/check.c | 6 ------
 1 file changed, 6 deletions(-)

diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 75ebaa0a6216..b8c288c02c99 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -2015,12 +2015,6 @@ static int validate_branch(struct objtool_file *file, struct symbol *func,
 	insn = first;
 	sec = insn->sec;
 
-	if (insn->alt_group && list_empty(&insn->alts)) {
-		WARN_FUNC("don't know how to handle branch to middle of alternative instruction group",
-			  sec, insn->offset);
-		return 1;
-	}
-
 	while (1) {
 		next_insn = next_insn_same_sec(file, insn);
 
-- 
2.21.1


  parent reply	other threads:[~2020-03-25  8:42 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-25  8:41 [PATCH 00/10] Objtool updates for easier portability Julien Thierry
2020-03-25  8:41 ` [PATCH 01/10] objtool: Move header sync-check ealier in build Julien Thierry
2020-03-25  8:41 ` [PATCH 02/10] objtool: check: Remove redundant checks on operand type Julien Thierry
2020-03-25  8:41 ` [PATCH 03/10] objtool: check: Clean instruction state before each function validation Julien Thierry
2020-03-25  8:41 ` [PATCH 04/10] objtool: check: Ignore empty alternative groups Julien Thierry
2020-03-25  8:41 ` Julien Thierry [this message]
2020-03-25  8:41 ` [PATCH 06/10] objtool: check: Use arch specific values in restore_reg() Julien Thierry
2020-03-25  8:42 ` [PATCH 07/10] objtool: check: Allow save/restore hint in non standard function symbols Julien Thierry
2020-03-25  8:42 ` [PATCH 08/10] objtool: Add abstraction for computation of symbols offsets Julien Thierry
2020-03-25  8:42 ` [PATCH 09/10] objtool: Split generic and arch specific CFI definitions Julien Thierry
2020-03-25  8:42 ` [PATCH 10/10] objtool: Support multiple stack_op per instruction Julien Thierry

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