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| author |   Hendrik Brueckner <brueckner@linux.vnet.ibm.com> | 2017-11-20 11:46:13 +0100 |
|---|---|---|
| committer |   Martin Schwidefsky <schwidefsky@de.ibm.com> | 2017-12-13 10:51:36 +0100 |
| commit | 7bceec4e58ee23be653c0dd366479d6cb64ae686 (patch) | |
| tree | cd285499f296c534522f812c6d4af6febd7aa8a2 /arch/s390/Makefile | |
| parent | s390/kernel: emit CFI data in .debug_frame and discard .eh_frame sections (diff) | |
| download | linux-dev-7bceec4e58ee23be653c0dd366479d6cb64ae686.tar.xz linux-dev-7bceec4e58ee23be653c0dd366479d6cb64ae686.zip | |
s390/vdso: revise CFI annotations of vDSO functions
Revise and add CFI CFA and register rule annotations to the vDSO
functions for proper stack unwinding and debugging.
Because glibc might call the vDSO in special ways, the vDSO code
does not rely on a stack frame created by the caller. The TOD clock
value can be therefore not stored in the pre-allocated stack area
and additional stack space is required.
To correctly annotate these situations with CFI, the .cfi_val_offset
directive is required to create relative offsets on the value of the
stack register %r15. Because the .cfi_val_offset directive is
available with recent GNU assembler versions only, additional checks
are necessary.
Note that if the vDSO is assembled with an older assembler version,
stack unwinding and debugging from within the vDSO code might not
be possible.
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/Makefile')
| -rw-r--r-- | arch/s390/Makefile | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/arch/s390/Makefile b/arch/s390/Makefile index 494bb9ad5edf..aa37ba79c762 100644 --- a/arch/s390/Makefile +++ b/arch/s390/Makefile @@ -88,10 +88,13 @@ KBUILD_CFLAGS += -DCC_USING_HOTPATCH endif endif +# Test CFI features of binutils +cfi := $(call as-instr,.cfi_startproc\n.cfi_val_offset 15$(comma)-160\n.cfi_endproc,-DCONFIG_AS_CFI_VAL_OFFSET=1) + 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) +KBUILD_CFLAGS += -fno-asynchronous-unwind-tables $(cfi) +KBUILD_AFLAGS += $(aflags-y) $(cfi) OBJCOPYFLAGS := -O binary |