diff options
| author | Saket Kumar Bhaskar <skb99@linux.ibm.com> | 2024-12-09 12:27:20 +0530 |
|---|---|---|
| committer | Andrii Nakryiko <andrii@kernel.org> | 2024-12-09 13:55:29 -0800 |
| commit | 4d33dc1bc31df80356c49e40dbd3ddff19500bcb (patch) | |
| tree | 0b04971c7b5aa144483aee8d0f3c63557faade9d /tools/testing/selftests/bpf/progs | |
| parent | 82c1f13de315f38ecdb63d8b0e63ad7d70994d55 (diff) | |
selftests/bpf: Fix fill_link_info selftest on powerpc
With CONFIG_KPROBES_ON_FTRACE enabled on powerpc, ftrace_location_range
returns ftrace location for bpf_fentry_test1 at offset of 4 bytes from
function entry. This is because branch to _mcount function is at offset
of 4 bytes in function profile sequence.
To fix this, add entry_offset of 4 bytes while verifying the address for
kprobe entry address of bpf_fentry_test1 in verify_perf_link_info in
selftest, when CONFIG_KPROBES_ON_FTRACE is enabled.
Disassemble of bpf_fentry_test1:
c000000000e4b080 <bpf_fentry_test1>:
c000000000e4b080: a6 02 08 7c mflr r0
c000000000e4b084: b9 e2 22 4b bl c00000000007933c <_mcount>
c000000000e4b088: 01 00 63 38 addi r3,r3,1
c000000000e4b08c: b4 07 63 7c extsw r3,r3
c000000000e4b090: 20 00 80 4e blr
When CONFIG_PPC_FTRACE_OUT_OF_LINE [1] is enabled, these function profile
sequence is moved out of line with an unconditional branch at offset 0.
So, the test works without altering the offset for
'CONFIG_KPROBES_ON_FTRACE && CONFIG_PPC_FTRACE_OUT_OF_LINE' case.
Disassemble of bpf_fentry_test1:
c000000000f95190 <bpf_fentry_test1>:
c000000000f95190: 00 00 00 60 nop
c000000000f95194: 01 00 63 38 addi r3,r3,1
c000000000f95198: b4 07 63 7c extsw r3,r3
c000000000f9519c: 20 00 80 4e blr
[1] https://lore.kernel.org/all/20241030070850.1361304-13-hbathini@linux.ibm.com/
Fixes: 23cf7aa539dc ("selftests/bpf: Add selftest for fill_link_info")
Signed-off-by: Saket Kumar Bhaskar <skb99@linux.ibm.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20241209065720.234344-1-skb99@linux.ibm.com
Diffstat (limited to 'tools/testing/selftests/bpf/progs')
| -rw-r--r-- | tools/testing/selftests/bpf/progs/test_fill_link_info.c | 13 |
1 files changed, 10 insertions, 3 deletions
diff --git a/tools/testing/selftests/bpf/progs/test_fill_link_info.c b/tools/testing/selftests/bpf/progs/test_fill_link_info.c index 6afa834756e9..fac33a14f200 100644 --- a/tools/testing/selftests/bpf/progs/test_fill_link_info.c +++ b/tools/testing/selftests/bpf/progs/test_fill_link_info.c @@ -6,13 +6,20 @@ #include <stdbool.h> extern bool CONFIG_X86_KERNEL_IBT __kconfig __weak; +extern bool CONFIG_PPC_FTRACE_OUT_OF_LINE __kconfig __weak; +extern bool CONFIG_KPROBES_ON_FTRACE __kconfig __weak; +extern bool CONFIG_PPC64 __kconfig __weak; -/* This function is here to have CONFIG_X86_KERNEL_IBT - * used and added to object BTF. +/* This function is here to have CONFIG_X86_KERNEL_IBT, + * CONFIG_PPC_FTRACE_OUT_OF_LINE, CONFIG_KPROBES_ON_FTRACE, + * CONFIG_PPC6 used and added to object BTF. */ int unused(void) { - return CONFIG_X86_KERNEL_IBT ? 0 : 1; + return CONFIG_X86_KERNEL_IBT || + CONFIG_PPC_FTRACE_OUT_OF_LINE || + CONFIG_KPROBES_ON_FTRACE || + CONFIG_PPC64 ? 0 : 1; } SEC("kprobe") |