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authorIlya Leoshkevich <iii@linux.ibm.com>2022-02-09 03:17:45 +0100
committerAndrii Nakryiko <andrii@kernel.org>2022-02-08 21:37:50 -0800
commit1f22a6f9f9a0f50218a11a0554709fd34a821fa3 (patch)
tree8a0c033171027bd17fd306411b10c34cac437b4b /tools/lib
parentfbca4a2f649730b67488a8b36140ce4d2cf13c63 (diff)
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libbpf: Fix accessing the first syscall argument on s390
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@kernel.org> Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20220209021745.2215452-11-iii@linux.ibm.com
Diffstat (limited to 'tools/lib')
-rw-r--r--tools/lib/bpf/bpf_tracing.h6
1 files changed, 6 insertions, 0 deletions
diff --git a/tools/lib/bpf/bpf_tracing.h b/tools/lib/bpf/bpf_tracing.h
index b6453107f75c..eb6eb3b28063 100644
--- a/tools/lib/bpf/bpf_tracing.h
+++ b/tools/lib/bpf/bpf_tracing.h
@@ -118,6 +118,10 @@
#elif defined(bpf_target_s390)
+struct pt_regs___s390 {
+ unsigned long orig_gpr2;
+};
+
/* 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]
@@ -130,6 +134,8 @@
#define __PT_RC_REG gprs[2]
#define __PT_SP_REG gprs[15]
#define __PT_IP_REG psw.addr
+#define PT_REGS_PARM1_SYSCALL(x) ({ _Pragma("GCC error \"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)
#elif defined(bpf_target_arm)