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?
Thanks,
Daniel
