On Fri, Aug 4, 2017 at 6:58 AM, Daniel Borkmann <dan...@iogearbox.net> wrote: > On 08/04/2017 07:46 AM, Joel Fernandes wrote: >> >> When cross-compiling the bpf sample map_perf_test for aarch64, I find that >> __NR_getpgrp is undefined. This causes build errors. Fix it by allowing >> the >> deprecated syscall in the sample. >> >> Signed-off-by: Joel Fernandes <joe...@google.com> >> --- >> samples/bpf/map_perf_test_user.c | 2 ++ >> 1 file changed, 2 insertions(+) >> >> diff --git a/samples/bpf/map_perf_test_user.c >> b/samples/bpf/map_perf_test_user.c >> index 1a8894b5ac51..6e6fc7121640 100644 >> --- a/samples/bpf/map_perf_test_user.c >> +++ b/samples/bpf/map_perf_test_user.c >> @@ -8,7 +8,9 @@ >> #include <sched.h> >> #include <stdio.h> >> #include <sys/types.h> >> +#define __ARCH_WANT_SYSCALL_DEPRECATED >> #include <asm/unistd.h> >> +#undef __ARCH_WANT_SYSCALL_DEPRECATED > > > So the only arch that sets __ARCH_WANT_SYSCALL_DEPRECATED > is score: > > $ git grep -n __ARCH_WANT_SYSCALL_DEPRECATED > arch/score/include/uapi/asm/unistd.h:7:#define > __ARCH_WANT_SYSCALL_DEPRECATED > include/uapi/asm-generic/unistd.h:837:#ifdef > __ARCH_WANT_SYSCALL_DEPRECATED > include/uapi/asm-generic/unistd.h:899:#endif /* > __ARCH_WANT_SYSCALL_DEPRECATED */ > > But even if this would make aarch64 compile, the syscall > numbers don't match up: > > $ git grep -n __NR_getpgrp include/uapi/asm-generic/unistd.h > include/uapi/asm-generic/unistd.h:841:#define __NR_getpgrp 1060 > include/uapi/asm-generic/unistd.h:843:__SYSCALL(__NR_getpgrp, sys_getpgrp) > > The only thing that can be found on arm64 is: > > $ git grep -n __NR_getpgrp arch/arm64/ > arch/arm64/include/asm/unistd32.h:154:#define __NR_getpgrp 65 > arch/arm64/include/asm/unistd32.h:155:__SYSCALL(__NR_getpgrp, sys_getpgrp) > > In arch/arm64/include/asm/unistd.h, it does include the > uapi/asm/unistd.h when compat is not set, but without the > __ARCH_WANT_SYSCALL_DEPRECATED. That doesn't look correct > unless I'm missing something, hmm, can't we just attach the > kprobes to a different syscall, one that is not deprecated, > so that we don't run into this in the first place?
Yes, I agree that's better. I think we can use getpgid. I'll try to whip something today and send it out. I also wanted to fix something else, HOSTCC is set to gcc, but I want the boostrap part of the sample to run an ARM so I have to make HOSTCC my cross-compiler. Right now I'm hacking it to point to the arm64 gcc however I think I'd like to add a 'cross compile mode' or something whether HOSTCC points to CROSS_COMPILE instead. I'm happy to discuss any ideas to get this fixed too. thanks! -Joel > > Thanks, > Daniel
