[PATCH 5.4 093/340] MIPS: properly stop .eh_frame generation
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: 2021-03-01 22:16:42
Also in:
lkml
Subsystem:
mips, the rest · Maintainers:
Thomas Bogendoerfer, Linus Torvalds
From: Alexander Lobakin <redacted>
[ Upstream commit 894ef530012fb5078466efdfb2c15d8b2f1565cd ]
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 <redacted>
Signed-off-by: Alexander Lobakin <redacted>
Reviewed-by: Kees Cook <redacted>
Reviewed-by: Nathan Chancellor <redacted>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
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 c23527ba65d09..64bffc1f75e0c 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 09770a4d97846..faf98f209b3f4 100644
--- a/arch/mips/kernel/vmlinux.lds.S
+++ b/arch/mips/kernel/vmlinux.lds.S@@ -226,6 +226,5 @@ SECTIONS *(.options) *(.pdr) *(.reginfo) - *(.eh_frame) } }
--
2.27.0