diff options
| author | Ilya Leoshkevich <iii@linux.ibm.com> | 2022-02-09 03:17:44 +0100 |
|---|---|---|
| committer | Andrii Nakryiko <andrii.nakryiko@gmail.com> | 2022-02-09 09:48:32 -0800 |
| commit | 9f6e3a7a59894af6ff9221083800556e68ffcd8a (patch) | |
| tree | 110d7ada34abf534fe01a37ff27a3c6137bf5e3e | |
| parent | f1a756d7935340abb489207686ad852911d26c41 (diff) | |
| download | libbpf-9f6e3a7a59894af6ff9221083800556e68ffcd8a.tar.gz | |
libbpf: Fix accessing the first syscall argument on arm64
On arm64, the first syscall argument should be accessed via orig_x0
(see arch/arm64/include/asm/syscall.h). Currently regs[0] is used
instead, leading to bpf_syscall_macro test failure.
orig_x0 cannot be added to struct 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: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220209021745.2215452-10-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 276130d..b645310 100644 --- a/src/bpf_tracing.h +++ b/src/bpf_tracing.h @@ -146,6 +146,10 @@ #elif defined(bpf_target_arm64) +struct pt_regs___arm64 { + unsigned long orig_x0; +}; + /* arm64 provides struct user_pt_regs instead of struct pt_regs to userspace */ #define __PT_REGS_CAST(x) ((const struct user_pt_regs *)(x)) #define __PT_PARM1_REG regs[0] @@ -158,6 +162,8 @@ #define __PT_RC_REG regs[0] #define __PT_SP_REG sp #define __PT_IP_REG pc +#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___arm64 *)(x), orig_x0) #elif defined(bpf_target_mips) |