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From: Julien Thierry <jthierry@redhat.com>
To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org
Cc: mark.rutland@arm.com, linux-efi@vger.kernel.org,
	michal.lkml@markovi.net, keescook@chromium.org,
	peterz@infradead.org, catalin.marinas@arm.com,
	masahiroy@kernel.org, broonie@kernel.org,
	linux-hardening@vger.kernel.org, jpoimboe@redhat.com,
	will@kernel.org, ardb@kernel.org,
	Julien Thierry <jthierry@redhat.com>
Subject: [RFC PATCH 14/17] objtool: arm64: Cache section with switch table information
Date: Wed, 20 Jan 2021 18:37:57 +0100	[thread overview]
Message-ID: <20210120173800.1660730-15-jthierry@redhat.com> (raw)
In-Reply-To: <20210120173800.1660730-1-jthierry@redhat.com>

Section ".discard.switch_table_info", created by the gcc plugin will
be looked up for every dynamic jump in the object file while the section
might not even exist.

Cache the result of the first lookup.

Signed-off-by: Julien Thierry <jthierry@redhat.com>
---
 tools/objtool/arch/arm64/special.c | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/tools/objtool/arch/arm64/special.c b/tools/objtool/arch/arm64/special.c
index 396b9c5feebd..c9c3e0bfd581 100644
--- a/tools/objtool/arch/arm64/special.c
+++ b/tools/objtool/arch/arm64/special.c
@@ -33,6 +33,19 @@ bool arch_support_alt_relocation(struct special_alt *special_alt,
 	return false;
 }
 
+static struct section *get_switch_table_info_section(struct objtool_file *file)
+{
+	static bool first = true;
+	static struct section *info_section = NULL;
+
+	if (first) {
+		first = false;
+		info_section = find_section_by_name(file->elf,
+						    ".discard.switch_table_info");
+	}
+
+	return info_section;
+}
 
 /*
  * Aarch64 jump tables are just arrays of offsets (of varying size/signess)
@@ -64,8 +77,7 @@ struct reloc *arch_find_switch_table(struct objtool_file *file,
 	void *sti_sec_start;
 	struct reloc *text_reloc;
 
-	table_info_sec = find_section_by_name(file->elf,
-					      ".discard.switch_table_info");
+	table_info_sec = get_switch_table_info_section(file);
 	if (!table_info_sec)
 		goto try_c_jmptbl;
 
-- 
2.25.4


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  parent reply	other threads:[~2021-01-20 17:47 UTC|newest]

Thread overview: 53+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-20 17:37 [RFC PATCH 00/17] objtool: add base support for arm64 Julien Thierry
2021-01-20 17:37 ` [RFC PATCH 01/17] tools: Add some generic functions and headers Julien Thierry
2021-01-20 17:37 ` [RFC PATCH 02/17] tools: arm64: Make aarch64 instruction decoder available to tools Julien Thierry
2021-01-20 17:37 ` [RFC PATCH 03/17] tools: bug: Remove duplicate definition Julien Thierry
2021-01-20 17:37 ` [RFC PATCH 04/17] objtool: arm64: Add base definition for arm64 backend Julien Thierry
2021-01-20 17:37 ` [RFC PATCH 05/17] objtool: arm64: Decode add/sub instructions Julien Thierry
2021-01-20 17:37 ` [RFC PATCH 06/17] objtool: arm64: Decode jump and call related instructions Julien Thierry
2021-01-20 17:37 ` [RFC PATCH 07/17] objtool: arm64: Decode other system instructions Julien Thierry
2021-01-20 17:37 ` [RFC PATCH 08/17] objtool: arm64: Decode load/store instructions Julien Thierry
2021-01-20 17:37 ` [RFC PATCH 09/17] objtool: arm64: Decode LDR instructions Julien Thierry
2021-01-20 17:37 ` [RFC PATCH 10/17] objtool: arm64: Accept padding in code sections Julien Thierry
2021-01-20 17:37 ` [RFC PATCH 11/17] efi: libstub: Ignore relocations for .discard sections Julien Thierry
2021-01-20 17:37 ` [RFC PATCH 12/17] gcc-plugins: objtool: Add plugin to detect switch table on arm64 Julien Thierry
2021-01-27 22:15   ` Nick Desaulniers
2021-01-27 23:26     ` Josh Poimboeuf
2021-01-29 18:10       ` Nick Desaulniers
2021-02-01 21:44         ` Josh Poimboeuf
2021-02-01 23:17           ` Nick Desaulniers
2021-02-02  0:02             ` Josh Poimboeuf
2021-02-02 14:24               ` David Laight
2021-02-02 22:33               ` Nick Desaulniers
2021-02-02 23:36                 ` Josh Poimboeuf
2021-02-02 23:52                   ` Nick Desaulniers
2021-02-02  8:57             ` Julien Thierry
2021-02-02 23:01               ` Nick Desaulniers
2021-02-03  0:14                 ` Josh Poimboeuf
2021-02-03 11:57                   ` Peter Zijlstra
2021-02-03 13:04                   ` Mark Brown
2021-02-03 13:58                   ` Mark Rutland
2021-02-03  8:11                 ` Julien Thierry
2021-02-09 16:30                 ` Daniel Kiss
2021-01-20 17:37 ` [RFC PATCH 13/17] objtool: arm64: Implement functions to add switch tables alternatives Julien Thierry
2021-01-20 17:37 ` Julien Thierry [this message]
2021-01-20 17:37 ` [RFC PATCH 15/17] objtool: arm64: Handle supported relocations in alternatives Julien Thierry
2021-01-20 17:37 ` [RFC PATCH 16/17] objtool: arm64: Ignore replacement section for alternative callback Julien Thierry
2021-01-20 17:38 ` [RFC PATCH 17/17] objtool: arm64: Enable stack validation for arm64 Julien Thierry
2021-01-21  9:03 ` [RFC PATCH 00/17] objtool: add base support " Ard Biesheuvel
2021-01-21 10:26   ` Julien Thierry
2021-01-21 11:08     ` Ard Biesheuvel
2021-01-21 11:23       ` Peter Zijlstra
2021-01-21 11:48         ` Ard Biesheuvel
2021-01-21 18:54           ` Josh Poimboeuf
2021-01-22 17:43             ` Mark Brown
2021-01-22 17:54               ` Ard Biesheuvel
2021-01-28 22:10                 ` Madhavan T. Venkataraman
2021-01-29 15:47                   ` Mark Brown
2021-01-22 21:15               ` Madhavan T. Venkataraman
2021-01-22 21:43                 ` Ard Biesheuvel
2021-01-22 21:44                   ` Madhavan T. Venkataraman
2021-01-25 21:19                   ` Josh Poimboeuf
2021-01-22 21:16               ` Madhavan T. Venkataraman
2021-01-21 13:23       ` Julien Thierry
2021-01-21 14:23         ` Mark Brown

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