On s390, the first syscall argument should be accessed via orig_gpr2
(see arch/s390/include/asm/syscall.h). Currently gpr[2] is used
instead, leading to bpf_syscall_macro test failure.
orig_gpr2 cannot be added to user_pt_regs, since its layout is a part
of the ABI. Therefore provide access to it only through
PT_REGS_PARM1_CORE_SYSCALL() by using a struct pt_regs flavor.
Reported-by: Andrii Nakryiko <andrii@xxxxxxxxxx>
Signed-off-by: Ilya Leoshkevich <iii@xxxxxxxxxxxxx>
---
tools/lib/bpf/bpf_tracing.h | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/tools/lib/bpf/bpf_tracing.h b/tools/lib/bpf/bpf_tracing.h
index 928f85f7961c..0e0414801457 100644
--- a/tools/lib/bpf/bpf_tracing.h
+++ b/tools/lib/bpf/bpf_tracing.h
@@ -114,9 +114,19 @@
#elif defined(bpf_target_s390)
+struct pt_regs___s390 {
+ unsigned long orig_gpr2;
+} __attribute__((preserve_access_index));
+
/* s390 provides user_pt_regs instead of struct pt_regs to userspace */
#define __PT_REGS_CAST(x) ((const user_pt_regs *)(x))
#define __PT_PARM1_REG gprs[2]
+#define PT_REGS_PARM1_SYSCALL(x) ({ \
+ _Pragma("GCC error \"PT_REGS_PARM1_SYSCALL() is not supported on s390, use PT_REGS_PARM1_CORE_SYSCALL() instead\""); \
+ 0l; \
+})
+#define PT_REGS_PARM1_CORE_SYSCALL(x) \
+ BPF_CORE_READ((const struct pt_regs___s390 *)(x), orig_gpr2)
#define __PT_PARM2_REG gprs[3]
#define __PT_PARM3_REG gprs[4]
#define __PT_PARM4_REG gprs[5]
--
2.34.1
