On 2021/12/18 0:45, Andrii Nakryiko wrote:

quoted

On Thu, Dec 16, 2021 at 6:25 PM Pu Lehui [off-list ref] wrote:

quoted

On 2021/12/16 12:06, Andrii Nakryiko wrote:

quoted

On Tue, Dec 14, 2021 at 5:54 AM Pu Lehui [off-list ref] wrote:

quoted

When building bpf selftests on arm64, the following error will occur:

progs/loop2.c:20:7: error: incomplete definition of type 'struct
user_pt_regs'

Some archs, like arm64 and riscv, use userspace pt_regs in
bpf_tracing.h, which causes build failure when bpf prog use
macro in bpf_tracing.h. So let's use vmlinux.h directly.

We could probably also extend bpf_tracing.h to work with
kernel-defined pt_regs, just like we do for x86 (see __KERNEL__ and
__VMLINUX_H__ checks). It's more work, but will benefit other end
users, not just selftests.

It might change a lot. We can use header file directory generated by
"make headers_install" to fix it.

We don't have dependency on "make headers_install" and I'd rather not 
add it.

What do you mean by "change a lot"?

Maybe I misunderstood your advice. Your suggestion might be to extend 
bpf_tracing.h to kernel-space pt_regs, while some archs, like arm64, 
only support user-space. So the patch might be like this:

diff --git a/tools/lib/bpf/bpf_tracing.h b/tools/lib/bpf/bpf_tracing.h
index db05a5937105..2c3cb8e9ae92 100644
--- a/tools/lib/bpf/bpf_tracing.h
+++ b/tools/lib/bpf/bpf_tracing.h

@@ -195,9 +195,13 @@ struct pt_regs;

  #elif defined(bpf_target_arm64)

-struct pt_regs;
+#if defined(__KERNEL__)
+#define PT_REGS_ARM64 const volatile struct pt_regs
+#else
  /* arm64 provides struct user_pt_regs instead of struct pt_regs to 

userspace */
  #define PT_REGS_ARM64 const volatile struct user_pt_regs
+#endif
+
  #define PT_REGS_PARM1(x) (((PT_REGS_ARM64 *)(x))->regs[0])
  #define PT_REGS_PARM2(x) (((PT_REGS_ARM64 *)(x))->regs[1])
  #define PT_REGS_PARM3(x) (((PT_REGS_ARM64 *)(x))->regs[2])