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| author | Ilya Leoshkevich <iii@linux.ibm.com> | 2022-02-09 03:17:45 +0100 |
|---|---|---|
| committer | Andrii Nakryiko <andrii.nakryiko@gmail.com> | 2022-02-09 09:48:32 -0800 |
| commit | f7e08b4a8f24ee23dc596710ff85fbcd2ad6f10f (patch) | |
| tree | 74172359dfadaa296ab732d0f07a2bad5963cd49 | |
| parent | 9f6e3a7a59894af6ff9221083800556e68ffcd8a (diff) | |
| download | libbpf-f7e08b4a8f24ee23dc596710ff85fbcd2ad6f10f.tar.gz | |
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
| -rw-r--r-- | src/bpf_tracing.h | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/src/bpf_tracing.h b/src/bpf_tracing.h index b645310..eb6eb3b 100644 --- a/src/bpf_tracing.h +++ b/src/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) |