[PATCH bpf-next v3 2/4] libbpf: Access first syscall argument with CO-RE direct read on arm64
From: Pu Lehui <hidden>
Date: 2024-08-31 04:16:55
Also in:
bpf, linux-riscv
Subsystem:
bpf [general] (safe dynamic programs and tools), bpf [library] (libbpf), the rest · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Linus Torvalds
From: Pu Lehui <pulehui@huawei.com> Currently PT_REGS_PARM1 SYSCALL(x) is consistent with PT_REGS_PARM1_CORE SYSCALL(x), which will introduce the overhead of BPF_CORE_READ(), taking into account the read pt_regs comes directly from the context, let's use CO-RE direct read to access the first system call argument. Suggested-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Pu Lehui <pulehui@huawei.com> --- tools/lib/bpf/bpf_tracing.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/tools/lib/bpf/bpf_tracing.h b/tools/lib/bpf/bpf_tracing.h
index e7d9382efeb3..051c408e6aed 100644
--- a/tools/lib/bpf/bpf_tracing.h
+++ b/tools/lib/bpf/bpf_tracing.h@@ -222,7 +222,7 @@ struct pt_regs___s390 { struct pt_regs___arm64 { unsigned long orig_x0; -}; +} __attribute__((preserve_access_index)); /* arm64 provides struct user_pt_regs instead of struct pt_regs to userspace */ #define __PT_REGS_CAST(x) ((const struct user_pt_regs *)(x))
@@ -241,7 +241,7 @@ struct pt_regs___arm64 { #define __PT_PARM4_SYSCALL_REG __PT_PARM4_REG #define __PT_PARM5_SYSCALL_REG __PT_PARM5_REG #define __PT_PARM6_SYSCALL_REG __PT_PARM6_REG -#define PT_REGS_PARM1_SYSCALL(x) PT_REGS_PARM1_CORE_SYSCALL(x) +#define PT_REGS_PARM1_SYSCALL(x) (((const struct pt_regs___arm64 *)(x))->orig_x0) #define PT_REGS_PARM1_CORE_SYSCALL(x) \ BPF_CORE_READ((const struct pt_regs___arm64 *)(x), __PT_PARM1_SYSCALL_REG)
--
2.34.1