lkml.org 
[lkml]   [2021]   [Dec]   [20]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
SubjectRe: [PATCH bpf-next] selftests/bpf: Fix building error when using userspace pt_regs
From
Date


On 2021/12/18 0:45, Andrii Nakryiko wrote:
> On Thu, Dec 16, 2021 at 6:25 PM Pu Lehui <pulehui@huawei.com> wrote:
>>
>>
>>
>> On 2021/12/16 12:06, Andrii Nakryiko wrote:
>>> On Tue, Dec 14, 2021 at 5:54 AM Pu Lehui <pulehui@huawei.com> wrote:
>>>>
>>>> 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])
>>
>> --- 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
>>>>
>>>> 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(-)
>>>>
>>>
>>> [...]
>>> .
>>>
> .
>

\
 
 \ /
  Last update: 2021-12-20 15:02    [W:0.238 / U:1.236 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site