On 2021/12/22 7:52, Andrii Nakryiko wrote:

On Mon, Dec 20, 2021 at 4:58 PM Pu Lehui [off-list ref] wrote:

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On 2021/12/20 22:02, Pu Lehui wrote:

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

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

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

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

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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,

yes

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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])

Please ignore the last reply. User-space pt_regs of arm64/s390 is the
first part of the kernel-space's, it should has covered both kernel and
userspace.

Alright, so is there still a problem or not? Looking at the definition
of struct pt_regs for arm64, just casting struct pt_regs to struct
user_pt_regs will indeed just work. So in that case, what was your
original issue?

Thanks for your reply. The original issue is, when arm64 bpf selftests 
cross compiling in x86_64 host, clang cannot find the arch specific uapi 
ptrace.h, and then the above error occur. Of course it works when 
compiling in arm64 host for it owns the corresponding uapi ptrace.h. So 
my suggestion is to add arch specific use header file directory 
generated by "make headers_install" for the cross compiling issue.

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--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile

@@ -294,7 +294,8 @@ MENDIAN=$(if

$(IS_LITTLE_ENDIAN),-mlittle-endian,-mbig-endian)
    CLANG_SYS_INCLUDES = $(call get_sys_includes,$(CLANG))
    BPF_CFLAGS = -g -D__TARGET_ARCH_$(SRCARCH) $(MENDIAN) \
               -I$(INCLUDE_DIR) -I$(CURDIR) -I$(APIDIR) \
-            -I$(abspath $(OUTPUT)/../usr/include)
+            -I$(abspath $(OUTPUT)/../usr/include) \
+            -I../../../../usr/include

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Signed-off-by: Pu Lehui <pulehui@huawei.com>
---
    tools/testing/selftests/bpf/progs/loop1.c     |  8 ++------
    tools/testing/selftests/bpf/progs/loop2.c     |  8 ++------
    tools/testing/selftests/bpf/progs/loop3.c     |  8 ++------
    tools/testing/selftests/bpf/progs/loop6.c     | 20
++++++-------------
    .../selftests/bpf/progs/test_overhead.c       |  8 ++------
    .../selftests/bpf/progs/test_probe_user.c     |  6 +-----
    6 files changed, 15 insertions(+), 43 deletions(-)

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