Messages in this thread | | | Subject | Re: [PATCH bpf-next] selftests/bpf: Fix building error when using userspace pt_regs | From | Pu Lehui <> | Date | Thu, 23 Dec 2021 12:52:14 +0800 |
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On 2021/12/23 7:17, Andrii Nakryiko wrote: > On Tue, Dec 21, 2021 at 5:33 PM Pu Lehui <pulehui@huawei.com> wrote: >> >> >> >> On 2021/12/22 7:52, Andrii Nakryiko wrote: >>> On Mon, Dec 20, 2021 at 4:58 PM Pu Lehui <pulehui@huawei.com> wrote: >>>> >>>> >>>> >>>> On 2021/12/20 22:02, Pu Lehui wrote: >>>>> >>>>> >>>>> 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, >>> >>> yes >>> >>>>> 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. > > I see. Can you try adding something like: > > ARCH_APIDIR := $(abspath ../../../../arch/$(SRCARCH)/include/uapi) > > and then add -I$(ARCH_APIDIR) to BPF_CFLAGS? > > Please let me know if that works for your cross-compilation case. > It works, thanks. I will add it to v2. >>>>>>> >>>>>>> --- a/tools/testing/selftests/bpf/Makefile >>>>>>> +++ b/tools/testing/selftests/bpf/Makefile >>>>>>> @@ -294,7 +294,8 @@ MENDIAN=$(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(-) >>>>>>>>> >>>>>>>> >>>>>>>> [...] >>>>>>>> . >>>>>>>> >>>>>> . >>>>>> >>>>> . >>> . >>> > . >
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