This replicates Josh's commit TODO ("x86/vdso: Enable sframe generation
in VDSO") for s390.
Enable SFrame generation in the vDSO library so kernel and user space
can unwind through it.
Signed-off-by: Jens Remus <jre...@linux.ibm.com>
---
Notes (jremus):
Link to latest x86 patch:
https://lore.kernel.org/all/20250425024023.173709...@goodmis.org/
arch/s390/include/asm/dwarf.h | 4 ++++
arch/s390/kernel/vdso64/Makefile | 7 ++++++-
arch/s390/kernel/vdso64/vdso64.lds.S | 5 +++++
3 files changed, 15 insertions(+), 1 deletion(-)
diff --git a/arch/s390/include/asm/dwarf.h b/arch/s390/include/asm/dwarf.h
index 5052ee6a40f7..aeb54e716d5a 100644
--- a/arch/s390/include/asm/dwarf.h
+++ b/arch/s390/include/asm/dwarf.h
@@ -16,7 +16,11 @@
* symbols for the .dbg file.
*/
+#ifdef CONFIG_AS_SFRAME
+ .cfi_sections .eh_frame, .debug_frame, .sframe
+#else
.cfi_sections .eh_frame, .debug_frame
+#endif
#define CFI_STARTPROC .cfi_startproc
#define CFI_ENDPROC .cfi_endproc
diff --git a/arch/s390/kernel/vdso64/Makefile b/arch/s390/kernel/vdso64/Makefile
index d8f0df742809..e96156b9c4df 100644
--- a/arch/s390/kernel/vdso64/Makefile
+++ b/arch/s390/kernel/vdso64/Makefile
@@ -20,7 +20,11 @@ targets := $(obj-vdso64) $(obj-cvdso64) vdso64.so
vdso64.so.dbg
obj-vdso64 := $(addprefix $(obj)/, $(obj-vdso64))
obj-cvdso64 := $(addprefix $(obj)/, $(obj-cvdso64))
-KBUILD_AFLAGS += -DBUILD_VDSO
+ifeq ($(CONFIG_AS_SFRAME),y)
+ SFRAME_CFLAGS := -Wa,--gsframe
+endif
+
+KBUILD_AFLAGS += -DBUILD_VDSO $(SFRAME_CFLAGS)
KBUILD_CFLAGS += -DBUILD_VDSO -DDISABLE_BRANCH_PROFILING
KBUILD_AFLAGS_64 := $(filter-out -m64,$(KBUILD_AFLAGS))
@@ -32,6 +36,7 @@ KBUILD_CFLAGS_64 := $(filter-out
-mno-pic-data-is-text-relative,$(KBUILD_CFLAGS_
KBUILD_CFLAGS_64 := $(filter-out -munaligned-symbols,$(KBUILD_CFLAGS_64))
KBUILD_CFLAGS_64 := $(filter-out
-fno-asynchronous-unwind-tables,$(KBUILD_CFLAGS_64))
KBUILD_CFLAGS_64 += -m64 -fPIC -fno-common -fno-builtin
-fasynchronous-unwind-tables
+KBUILD_CFLAGS_64 += $(SFRAME_CFLAGS)
ldflags-y := -shared -soname=linux-vdso64.so.1 \
--hash-style=both --build-id=sha1 -T
diff --git a/arch/s390/kernel/vdso64/vdso64.lds.S
b/arch/s390/kernel/vdso64/vdso64.lds.S
index e4f6551ae898..7acecb0d9b7e 100644
--- a/arch/s390/kernel/vdso64/vdso64.lds.S
+++ b/arch/s390/kernel/vdso64/vdso64.lds.S
@@ -50,6 +50,9 @@ SECTIONS
.eh_frame_hdr : { *(.eh_frame_hdr) } :text :eh_frame_hdr
.eh_frame : { KEEP (*(.eh_frame)) } :text
+
+ .sframe : { *(.sframe) } :text :sframe
+
.gcc_except_table : { *(.gcc_except_table .gcc_except_table.*) }
.rela.dyn ALIGN(8) : { *(.rela.dyn) }
@@ -114,6 +117,7 @@ SECTIONS
* Very old versions of ld do not recognize this name token; use the constant.
*/
#define PT_GNU_EH_FRAME 0x6474e550
+#define PT_GNU_SFRAME 0x6474e554
/*
* We must supply the ELF program headers explicitly to get just one
@@ -125,6 +129,7 @@ PHDRS
dynamic PT_DYNAMIC FLAGS(4); /* PF_R */
note PT_NOTE FLAGS(4); /* PF_R */
eh_frame_hdr PT_GNU_EH_FRAME;
+ sframe PT_GNU_SFRAME;
}
/*
--
2.48.1
