On s390 64-bit the s390x ELF ABI [1] designates register 11 as the
"preferred" frame pointer (FP) register in user space.
[1]: s390x ELF ABI, https://github.com/IBM/s390x-abi/releases
Signed-off-by: Jens Remus <redacted>
---
Notes (jremus):
Cherry-picked from "[PATCH v4 00/12] s390: SFrame user space unwinding"
series and adjusted to .eh_frame:
https://lore.kernel.org/all/20260127151926.2805123-9-jremus@linux.ibm.com/ (local)
arch/s390/include/asm/ptrace.h | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/arch/s390/include/asm/ptrace.h b/arch/s390/include/asm/ptrace.h
index 495e310c3d6d..85765979a595 100644
--- a/arch/s390/include/asm/ptrace.h
+++ b/arch/s390/include/asm/ptrace.h
@@ -255,6 +255,12 @@ static __always_inline unsigned long user_stack_pointer(const struct pt_regs *re
return regs->gprs[15];
}
+static __always_inline unsigned long frame_pointer(const struct pt_regs *regs)
+{
+ /* Return ABI-designated "preferred" frame-pointer register value. */
+ return regs->gprs[11];
+}
+
static __always_inline unsigned long regs_get_register(const struct pt_regs *regs,
unsigned int offset)
{--
2.53.0