diff options
| author | Ilya Leoshkevich | 2019-07-04 16:18:15 +0200 |
|---|---|---|
| committer | Vasily Gorbik | 2019-11-30 10:52:44 +0100 |
| commit | 914d52e46490b6599b7f03fad233f4f19bf23cf7 (patch) | |
| tree | fc4a50362037e203cfacff290f77f8db02df8fb6 /arch/s390 | |
| parent | ea1f56fa16ae5f6e67f6ea03836b36c6053d33d1 (diff) | |
s390: implement perf_arch_fetch_caller_regs
On s390 bpf_get_stack_raw_tp() returns 0 entries for both kernel and
user stacks. While there is no practical unwinding solution for userspace
on s390 at this moment, there certainly is a kernel unwinder. However,
it is not properly integrated with BPF.
In order to start unwinding, bpf_get_stack_raw_tp() obtains the current
kernel register values using perf_fetch_caller_regs(), which is not
implemented for s390. The actual unwinding then happens by passing those
registers to perf_callchain_kernel().
Implement perf_arch_fetch_caller_regs() for s390, where
__builtin_frame_address(0) points to back_chain.
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Diffstat (limited to 'arch/s390')
| -rw-r--r-- | arch/s390/include/asm/perf_event.h | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/arch/s390/include/asm/perf_event.h b/arch/s390/include/asm/perf_event.h index 4652ffffe0b2..b9da71632827 100644 --- a/arch/s390/include/asm/perf_event.h +++ b/arch/s390/include/asm/perf_event.h @@ -12,6 +12,7 @@ #include <linux/perf_event.h> #include <linux/device.h> +#include <asm/stacktrace.h> /* Per-CPU flags for PMU states */ #define PMU_F_RESERVED 0x1000 @@ -73,4 +74,10 @@ struct perf_sf_sde_regs { #define SDB_FULL_BLOCKS(hwc) (SAMPL_FLAGS(hwc) & PERF_CPUM_SF_FULL_BLOCKS) #define SAMPLE_FREQ_MODE(hwc) (SAMPL_FLAGS(hwc) & PERF_CPUM_SF_FREQ_MODE) +#define perf_arch_fetch_caller_regs(regs, __ip) do { \ + (regs)->psw.addr = (__ip); \ + (regs)->gprs[15] = (unsigned long)__builtin_frame_address(0) - \ + offsetof(struct stack_frame, back_chain); \ +} while (0) + #endif /* _ASM_S390_PERF_EVENT_H */ |