diff options
Diffstat (limited to 'kernel/bpf/stackmap.c')
| -rw-r--r-- | kernel/bpf/stackmap.c | 80 |
1 files changed, 72 insertions, 8 deletions
diff --git a/kernel/bpf/stackmap.c b/kernel/bpf/stackmap.c index 57eeb1234b67..3ba102b41512 100644 --- a/kernel/bpf/stackmap.c +++ b/kernel/bpf/stackmap.c @@ -262,16 +262,11 @@ out: return ret; } -static void stack_map_get_build_id_offset(struct bpf_map *map, - struct stack_map_bucket *bucket, +static void stack_map_get_build_id_offset(struct bpf_stack_build_id *id_offs, u64 *ips, u32 trace_nr, bool user) { int i; struct vm_area_struct *vma; - struct bpf_stack_build_id *id_offs; - - bucket->nr = trace_nr; - id_offs = (struct bpf_stack_build_id *)bucket->data; /* * We cannot do up_read() in nmi context, so build_id lookup is @@ -361,8 +356,10 @@ BPF_CALL_3(bpf_get_stackid, struct pt_regs *, regs, struct bpf_map *, map, pcpu_freelist_pop(&smap->freelist); if (unlikely(!new_bucket)) return -ENOMEM; - stack_map_get_build_id_offset(map, new_bucket, ips, - trace_nr, user); + new_bucket->nr = trace_nr; + stack_map_get_build_id_offset( + (struct bpf_stack_build_id *)new_bucket->data, + ips, trace_nr, user); trace_len = trace_nr * sizeof(struct bpf_stack_build_id); if (hash_matches && bucket->nr == trace_nr && memcmp(bucket->data, new_bucket->data, trace_len) == 0) { @@ -405,6 +402,73 @@ const struct bpf_func_proto bpf_get_stackid_proto = { .arg3_type = ARG_ANYTHING, }; +BPF_CALL_4(bpf_get_stack, struct pt_regs *, regs, void *, buf, u32, size, + u64, flags) +{ + u32 init_nr, trace_nr, copy_len, elem_size, num_elem; + bool user_build_id = flags & BPF_F_USER_BUILD_ID; + u32 skip = flags & BPF_F_SKIP_FIELD_MASK; + bool user = flags & BPF_F_USER_STACK; + struct perf_callchain_entry *trace; + bool kernel = !user; + int err = -EINVAL; + u64 *ips; + + if (unlikely(flags & ~(BPF_F_SKIP_FIELD_MASK | BPF_F_USER_STACK | + BPF_F_USER_BUILD_ID))) + goto clear; + if (kernel && user_build_id) + goto clear; + + elem_size = (user && user_build_id) ? sizeof(struct bpf_stack_build_id) + : sizeof(u64); + if (unlikely(size % elem_size)) + goto clear; + + num_elem = size / elem_size; + if (sysctl_perf_event_max_stack < num_elem) + init_nr = 0; + else + init_nr = sysctl_perf_event_max_stack - num_elem; + trace = get_perf_callchain(regs, init_nr, kernel, user, + sysctl_perf_event_max_stack, false, false); + if (unlikely(!trace)) + goto err_fault; + + trace_nr = trace->nr - init_nr; + if (trace_nr < skip) + goto err_fault; + + trace_nr -= skip; + trace_nr = (trace_nr <= num_elem) ? trace_nr : num_elem; + copy_len = trace_nr * elem_size; + ips = trace->ip + skip + init_nr; + if (user && user_build_id) + stack_map_get_build_id_offset(buf, ips, trace_nr, user); + else + memcpy(buf, ips, copy_len); + + if (size > copy_len) + memset(buf + copy_len, 0, size - copy_len); + return copy_len; + +err_fault: + err = -EFAULT; +clear: + memset(buf, 0, size); + return err; +} + +const struct bpf_func_proto bpf_get_stack_proto = { + .func = bpf_get_stack, + .gpl_only = true, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_CTX, + .arg2_type = ARG_PTR_TO_UNINIT_MEM, + .arg3_type = ARG_CONST_SIZE_OR_ZERO, + .arg4_type = ARG_ANYTHING, +}; + /* Called from eBPF program */ static void *stack_map_lookup_elem(struct bpf_map *map, void *key) { |