diff options
author | Hendrik Brueckner <brueckner@linux.vnet.ibm.com> | 2017-11-20 11:41:07 +0100 |
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committer | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2017-12-13 10:51:35 +0100 |
commit | bc3703f21cec8a2ac6a64f6fb3686fbcb1ba1513 (patch) | |
tree | 8afb21635860b1ba73e8d5be04536b626cbb338b /arch/s390 | |
parent | a5f1005517534aeb1fac20180badfbf0896c183c (diff) | |
download | linux-stable-bc3703f21cec8a2ac6a64f6fb3686fbcb1ba1513.tar.gz linux-stable-bc3703f21cec8a2ac6a64f6fb3686fbcb1ba1513.tar.bz2 linux-stable-bc3703f21cec8a2ac6a64f6fb3686fbcb1ba1513.zip |
s390/kernel: emit CFI data in .debug_frame and discard .eh_frame sections
Using perf probe and libdw on kernel modules failed to find CFI
data for symbols. The CFI data is stored in the .eh_frame section.
The elfutils libdw is not able to extract the CFI data correctly,
because the .eh_frame section requires "non-simple" relocations
for kernel modules.
The suggestion is to avoid these "non-simple" relocations by emitting
the CFI data in the .debug_frame section. Let gcc emit respective
directives by specifying the -fno-asynchronous-unwind-tables option.
Using the .debug_frame section for CFI data, the .eh_frame section
becomes unused and, thus, discard it for kernel and modules builds
The vDSO requires the .eh_frame section and, hence, emit the CFI data
in both, the .eh_frame and .debug_frame sections.
See also discussion on elfutils/libdw bugzilla:
https://sourceware.org/bugzilla/show_bug.cgi?id=22452
Suggested-by: Mark Wielaard <mark@klomp.org>
Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390')
-rw-r--r-- | arch/s390/Makefile | 1 | ||||
-rw-r--r-- | arch/s390/include/asm/dwarf.h | 25 | ||||
-rw-r--r-- | arch/s390/kernel/vdso32/Makefile | 3 | ||||
-rw-r--r-- | arch/s390/kernel/vdso32/clock_getres.S | 1 | ||||
-rw-r--r-- | arch/s390/kernel/vdso32/clock_gettime.S | 1 | ||||
-rw-r--r-- | arch/s390/kernel/vdso32/getcpu.S | 1 | ||||
-rw-r--r-- | arch/s390/kernel/vdso32/gettimeofday.S | 1 | ||||
-rw-r--r-- | arch/s390/kernel/vdso64/Makefile | 3 | ||||
-rw-r--r-- | arch/s390/kernel/vdso64/clock_getres.S | 1 | ||||
-rw-r--r-- | arch/s390/kernel/vdso64/clock_gettime.S | 1 | ||||
-rw-r--r-- | arch/s390/kernel/vdso64/getcpu.S | 1 | ||||
-rw-r--r-- | arch/s390/kernel/vdso64/gettimeofday.S | 1 | ||||
-rw-r--r-- | arch/s390/kernel/vmlinux.lds.S | 3 |
13 files changed, 43 insertions, 0 deletions
diff --git a/arch/s390/Makefile b/arch/s390/Makefile index de54cfc6109d..494bb9ad5edf 100644 --- a/arch/s390/Makefile +++ b/arch/s390/Makefile @@ -90,6 +90,7 @@ endif KBUILD_CFLAGS += -mbackchain -msoft-float $(cflags-y) KBUILD_CFLAGS += -pipe -fno-strength-reduce -Wno-sign-compare +KBUILD_CFLAGS += -fno-asynchronous-unwind-tables KBUILD_AFLAGS += $(aflags-y) OBJCOPYFLAGS := -O binary diff --git a/arch/s390/include/asm/dwarf.h b/arch/s390/include/asm/dwarf.h new file mode 100644 index 000000000000..dffdb81e534f --- /dev/null +++ b/arch/s390/include/asm/dwarf.h @@ -0,0 +1,25 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _ASM_S390_DWARF_H +#define _ASM_S390_DWARF_H + +#ifdef __ASSEMBLY__ + +#ifndef BUILD_VDSO + /* + * Emit CFI data in .debug_frame sections and not in .eh_frame + * sections. The .eh_frame CFI is used for runtime unwind + * information that is not being used. Hence, vmlinux.lds.S + * can discard the .eh_frame sections. + */ + .cfi_sections .debug_frame +#else + /* + * For vDSO, emit CFI data in both, .eh_frame and .debug_frame + * sections. + */ + .cfi_sections .eh_frame, .debug_frame +#endif + +#endif /* __ASSEMBLY__ */ + +#endif /* _ASM_S390_DWARF_H */ diff --git a/arch/s390/kernel/vdso32/Makefile b/arch/s390/kernel/vdso32/Makefile index 308564b9bf68..c5c856f320bc 100644 --- a/arch/s390/kernel/vdso32/Makefile +++ b/arch/s390/kernel/vdso32/Makefile @@ -10,6 +10,9 @@ obj-vdso32 = gettimeofday.o clock_getres.o clock_gettime.o note.o getcpu.o targets := $(obj-vdso32) vdso32.so vdso32.so.dbg obj-vdso32 := $(addprefix $(obj)/, $(obj-vdso32)) +KBUILD_AFLAGS += -DBUILD_VDSO +KBUILD_CFLAGS += -DBUILD_VDSO + KBUILD_AFLAGS_31 := $(filter-out -m64,$(KBUILD_AFLAGS)) KBUILD_AFLAGS_31 += -m31 -s diff --git a/arch/s390/kernel/vdso32/clock_getres.S b/arch/s390/kernel/vdso32/clock_getres.S index f61df5253c23..6aeddf8e4bc7 100644 --- a/arch/s390/kernel/vdso32/clock_getres.S +++ b/arch/s390/kernel/vdso32/clock_getres.S @@ -9,6 +9,7 @@ #include <asm/vdso.h> #include <asm/asm-offsets.h> #include <asm/unistd.h> +#include <asm/dwarf.h> .text .align 4 diff --git a/arch/s390/kernel/vdso32/clock_gettime.S b/arch/s390/kernel/vdso32/clock_gettime.S index 2d6ec3abe095..d0ac32c413e2 100644 --- a/arch/s390/kernel/vdso32/clock_gettime.S +++ b/arch/s390/kernel/vdso32/clock_gettime.S @@ -9,6 +9,7 @@ #include <asm/vdso.h> #include <asm/asm-offsets.h> #include <asm/unistd.h> +#include <asm/dwarf.h> .text .align 4 diff --git a/arch/s390/kernel/vdso32/getcpu.S b/arch/s390/kernel/vdso32/getcpu.S index 5477a2c112fb..539d92a2c61b 100644 --- a/arch/s390/kernel/vdso32/getcpu.S +++ b/arch/s390/kernel/vdso32/getcpu.S @@ -8,6 +8,7 @@ */ #include <asm/vdso.h> #include <asm/asm-offsets.h> +#include <asm/dwarf.h> .text .align 4 diff --git a/arch/s390/kernel/vdso32/gettimeofday.S b/arch/s390/kernel/vdso32/gettimeofday.S index aa8bf13a2edb..435f819c3e65 100644 --- a/arch/s390/kernel/vdso32/gettimeofday.S +++ b/arch/s390/kernel/vdso32/gettimeofday.S @@ -9,6 +9,7 @@ #include <asm/vdso.h> #include <asm/asm-offsets.h> #include <asm/unistd.h> +#include <asm/dwarf.h> .text .align 4 diff --git a/arch/s390/kernel/vdso64/Makefile b/arch/s390/kernel/vdso64/Makefile index f81ae7998883..15b1ceafc4c1 100644 --- a/arch/s390/kernel/vdso64/Makefile +++ b/arch/s390/kernel/vdso64/Makefile @@ -10,6 +10,9 @@ obj-vdso64 = gettimeofday.o clock_getres.o clock_gettime.o note.o getcpu.o targets := $(obj-vdso64) vdso64.so vdso64.so.dbg obj-vdso64 := $(addprefix $(obj)/, $(obj-vdso64)) +KBUILD_AFLAGS += -DBUILD_VDSO +KBUILD_CFLAGS += -DBUILD_VDSO + KBUILD_AFLAGS_64 := $(filter-out -m64,$(KBUILD_AFLAGS)) KBUILD_AFLAGS_64 += -m64 -s diff --git a/arch/s390/kernel/vdso64/clock_getres.S b/arch/s390/kernel/vdso64/clock_getres.S index faf5213b15df..5b0d9c380de2 100644 --- a/arch/s390/kernel/vdso64/clock_getres.S +++ b/arch/s390/kernel/vdso64/clock_getres.S @@ -9,6 +9,7 @@ #include <asm/vdso.h> #include <asm/asm-offsets.h> #include <asm/unistd.h> +#include <asm/dwarf.h> .text .align 4 diff --git a/arch/s390/kernel/vdso64/clock_gettime.S b/arch/s390/kernel/vdso64/clock_gettime.S index 6046b3bfca46..deccd793b279 100644 --- a/arch/s390/kernel/vdso64/clock_gettime.S +++ b/arch/s390/kernel/vdso64/clock_gettime.S @@ -9,6 +9,7 @@ #include <asm/vdso.h> #include <asm/asm-offsets.h> #include <asm/unistd.h> +#include <asm/dwarf.h> .text .align 4 diff --git a/arch/s390/kernel/vdso64/getcpu.S b/arch/s390/kernel/vdso64/getcpu.S index e9c34364d97b..022acdecd5b9 100644 --- a/arch/s390/kernel/vdso64/getcpu.S +++ b/arch/s390/kernel/vdso64/getcpu.S @@ -8,6 +8,7 @@ */ #include <asm/vdso.h> #include <asm/asm-offsets.h> +#include <asm/dwarf.h> .text .align 4 diff --git a/arch/s390/kernel/vdso64/gettimeofday.S b/arch/s390/kernel/vdso64/gettimeofday.S index cc9dbc27da6f..964afb1de06d 100644 --- a/arch/s390/kernel/vdso64/gettimeofday.S +++ b/arch/s390/kernel/vdso64/gettimeofday.S @@ -9,6 +9,7 @@ #include <asm/vdso.h> #include <asm/asm-offsets.h> #include <asm/unistd.h> +#include <asm/dwarf.h> .text .align 4 diff --git a/arch/s390/kernel/vmlinux.lds.S b/arch/s390/kernel/vmlinux.lds.S index a049ff005f03..608cf2987d19 100644 --- a/arch/s390/kernel/vmlinux.lds.S +++ b/arch/s390/kernel/vmlinux.lds.S @@ -141,4 +141,7 @@ SECTIONS /* Sections to be discarded */ DISCARDS + /DISCARD/ : { + *(.eh_frame) + } } |