From: Alexander Lobakin <alobakin@pm.me>
To: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Arnd Bergmann <arnd@arndb.de>,
Nathan Chancellor <natechancellor@gmail.com>,
Nick Desaulniers <ndesaulniers@google.com>,
Huacai Chen <chenhuacai@kernel.org>,
Pei Huang <huangpei@loongson.cn>,
Kees Cook <keescook@chromium.org>,
Alexander Lobakin <alobakin@pm.me>,
Fangrui Song <maskray@google.com>,
Jiaxun Yang <jiaxun.yang@flygoat.com>,
Ralf Baechle <ralf@linux-mips.org>,
Corey Minyard <cminyard@mvista.com>,
linux-mips@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-arch@vger.kernel.org, stable@vger.kernel.org,
clang-built-linux@googlegroups.com
Subject: [PATCH v5 mips-next 4/9] MIPS: properly stop .eh_frame generation
Date: Sun, 10 Jan 2021 11:56:28 +0000 [thread overview]
Message-ID: <20210110115546.30970-4-alobakin@pm.me> (raw)
In-Reply-To: <20210110115546.30970-1-alobakin@pm.me>
Commit 866b6a89c6d1 ("MIPS: Add DWARF unwinding to assembly") added
-fno-asynchronous-unwind-tables to KBUILD_CFLAGS to prevent compiler
from emitting .eh_frame symbols.
However, as MIPS heavily uses CFI, that's not enough. Use the
approach taken for x86 (as it also uses CFI) and explicitly put CFI
symbols into the .debug_frame section (except for VDSO).
This allows us to drop .eh_frame from DISCARDS as it's no longer
being generated.
Fixes: 866b6a89c6d1 ("MIPS: Add DWARF unwinding to assembly")
Suggested-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Alexander Lobakin <alobakin@pm.me>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
---
arch/mips/include/asm/asm.h | 18 ++++++++++++++++++
arch/mips/kernel/vmlinux.lds.S | 1 -
2 files changed, 18 insertions(+), 1 deletion(-)
diff --git a/arch/mips/include/asm/asm.h b/arch/mips/include/asm/asm.h
index 3682d1a0bb80..ea4b62ece336 100644
--- a/arch/mips/include/asm/asm.h
+++ b/arch/mips/include/asm/asm.h
@@ -20,10 +20,27 @@
#include <asm/sgidefs.h>
#include <asm/asm-eva.h>
+#ifndef __VDSO__
+/*
+ * Emit CFI data in .debug_frame sections, not .eh_frame sections.
+ * We don't do DWARF unwinding at runtime, so only the offline DWARF
+ * information is useful to anyone. Note we should change this if we
+ * ever decide to enable DWARF unwinding at runtime.
+ */
+#define CFI_SECTIONS .cfi_sections .debug_frame
+#else
+ /*
+ * For the vDSO, emit both runtime unwind information and debug
+ * symbols for the .dbg file.
+ */
+#define CFI_SECTIONS
+#endif
+
/*
* LEAF - declare leaf routine
*/
#define LEAF(symbol) \
+ CFI_SECTIONS; \
.globl symbol; \
.align 2; \
.type symbol, @function; \
@@ -36,6 +53,7 @@ symbol: .frame sp, 0, ra; \
* NESTED - declare nested routine entry point
*/
#define NESTED(symbol, framesize, rpc) \
+ CFI_SECTIONS; \
.globl symbol; \
.align 2; \
.type symbol, @function; \
diff --git a/arch/mips/kernel/vmlinux.lds.S b/arch/mips/kernel/vmlinux.lds.S
index 09669a8fddec..10d8f0dcb76b 100644
--- a/arch/mips/kernel/vmlinux.lds.S
+++ b/arch/mips/kernel/vmlinux.lds.S
@@ -224,6 +224,5 @@ SECTIONS
*(.options)
*(.pdr)
*(.reginfo)
- *(.eh_frame)
}
}
--
2.30.0
next prev parent reply other threads:[~2021-01-10 11:57 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-10 11:53 [PATCH v5 mips-next 0/9] MIPS: vmlinux.lds.S sections fixes & cleanup Alexander Lobakin
2021-01-10 11:56 ` [PATCH v5 mips-next 1/9] MIPS: vmlinux.lds.S: add missing PAGE_ALIGNED_DATA() section Alexander Lobakin
2021-01-10 11:56 ` [PATCH v5 mips-next 2/9] MIPS: CPS: don't create redundant .text.cps-vec section Alexander Lobakin
2021-01-10 11:56 ` [PATCH v5 mips-next 3/9] MIPS: vmlinux.lds.S: add ".gnu.attributes" to DISCARDS Alexander Lobakin
2021-01-10 11:56 ` Alexander Lobakin [this message]
2021-01-10 11:56 ` [PATCH v5 mips-next 5/9] MIPS: vmlinux.lds.S: explicitly catch .rel.dyn symbols Alexander Lobakin
2021-01-11 1:28 ` Nathan Chancellor
2021-01-10 11:56 ` [PATCH v5 mips-next 6/9] MIPS: vmlinux.lds.S: explicitly declare .got table Alexander Lobakin
2021-01-10 11:56 ` [PATCH v5 mips-next 7/9] vmlinux.lds.h: catch compound literals into data and BSS Alexander Lobakin
2021-01-10 11:56 ` [PATCH v5 mips-next 8/9] vmlinux.lds.h: catch UBSAN's "unnamed data" into data Alexander Lobakin
2021-01-11 2:05 ` Nathan Chancellor
2021-01-10 11:57 ` [PATCH v5 mips-next 9/9] MIPS: select ARCH_WANT_LD_ORPHAN_WARN Alexander Lobakin
2021-01-11 19:53 ` [PATCH v5 mips-next 0/9] MIPS: vmlinux.lds.S sections fixes & cleanup Kees Cook
2021-01-11 20:57 ` Alexander Lobakin
2021-01-11 22:43 ` Thomas Bogendoerfer
2021-01-15 11:15 ` Arnd Bergmann
2021-01-15 14:40 ` Thomas Bogendoerfer
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20210110115546.30970-4-alobakin@pm.me \
--to=alobakin@pm.me \
--cc=arnd@arndb.de \
--cc=chenhuacai@kernel.org \
--cc=clang-built-linux@googlegroups.com \
--cc=cminyard@mvista.com \
--cc=huangpei@loongson.cn \
--cc=jiaxun.yang@flygoat.com \
--cc=keescook@chromium.org \
--cc=linux-arch@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mips@vger.kernel.org \
--cc=maskray@google.com \
--cc=natechancellor@gmail.com \
--cc=ndesaulniers@google.com \
--cc=ralf@linux-mips.org \
--cc=stable@vger.kernel.org \
--cc=tsbogend@alpha.franken.de \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).