[RFC PATCH v1 3/5] s390/vdso: Annotate __kernel_[rt_]sigreturn as signal frames
From: Jens Remus <hidden>
Date: 2026-01-27 15:33:57
Also in:
bpf, linux-s390, lkml
Subsystem:
s390 architecture, the rest · Maintainers:
Heiko Carstens, Vasily Gorbik, Alexander Gordeev, Linus Torvalds
The GNU assembler supports CFI directive .cfi_signal_frame with binutils 2.17+. Use it to annotate the vDSO functions __kernel_sigreturn() and __kernel_rt_sigreturn() as signal frames. This enables generation of SFrame stack trace information for the vDSO to likewise annotate these functions for use in stack tracers, such as the kernel unwind user sframe. Signed-off-by: Jens Remus <redacted> --- arch/s390/include/asm/dwarf.h | 3 +++ arch/s390/kernel/vdso/vdso_user_wrapper.S | 15 +++++++++++++-- 2 files changed, 16 insertions(+), 2 deletions(-)
diff --git a/arch/s390/include/asm/dwarf.h b/arch/s390/include/asm/dwarf.h
index 2f148b15fd7d..e5663d6b11db 100644
--- a/arch/s390/include/asm/dwarf.h
+++ b/arch/s390/include/asm/dwarf.h@@ -35,6 +35,8 @@ #define CFI_VAL_OFFSET nocfi #endif +#define CFI_SIGNAL_FRAME .cfi_signal_frame + #else /* !BUILD_VDSO */ /*
@@ -49,6 +51,7 @@ #define CFI_RESTORE nocfi #define CFI_REL_OFFSET nocfi #define CFI_VAL_OFFSET nocfi +#define CFI_SIGNAL_FRAME nocfi #endif /* !BUILD_VDSO */
diff --git a/arch/s390/kernel/vdso/vdso_user_wrapper.S b/arch/s390/kernel/vdso/vdso_user_wrapper.S
index aa06c85bcbd3..757503929ab0 100644
--- a/arch/s390/kernel/vdso/vdso_user_wrapper.S
+++ b/arch/s390/kernel/vdso/vdso_user_wrapper.S@@ -47,6 +47,17 @@ SYM_FUNC_START(__kernel_\func) SYM_FUNC_END(__kernel_\func) .endm +.macro vdso_syscall_sf func,syscall +SYM_FUNC_START(__kernel_\func) + CFI_STARTPROC simple + CFI_SIGNAL_FRAME + svc \syscall + /* Trap, if syscall returns, which shouldn't happen */ + .insn e,0x0000 + CFI_ENDPROC +SYM_FUNC_END(__kernel_\func) +.endm + vdso_syscall restart_syscall,__NR_restart_syscall -vdso_syscall sigreturn,__NR_sigreturn -vdso_syscall rt_sigreturn,__NR_rt_sigreturn +vdso_syscall_sf sigreturn,__NR_sigreturn +vdso_syscall_sf rt_sigreturn,__NR_rt_sigreturn
--
2.51.0