diff options
Diffstat (limited to 'tools/testing/selftests/bpf/trace_helpers.c')
| -rw-r--r-- | tools/testing/selftests/bpf/trace_helpers.c | 226 |
1 files changed, 226 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/trace_helpers.c b/tools/testing/selftests/bpf/trace_helpers.c new file mode 100644 index 000000000..9c4be2cdb --- /dev/null +++ b/tools/testing/selftests/bpf/trace_helpers.c @@ -0,0 +1,226 @@ +// SPDX-License-Identifier: GPL-2.0 +#include <ctype.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <assert.h> +#include <errno.h> +#include <fcntl.h> +#include <poll.h> +#include <unistd.h> +#include <linux/perf_event.h> +#include <sys/mman.h> +#include "trace_helpers.h" + +#define DEBUGFS "/sys/kernel/debug/tracing/" + +#define MAX_SYMS 300000 +static struct ksym syms[MAX_SYMS]; +static int sym_cnt; + +static int ksym_cmp(const void *p1, const void *p2) +{ + return ((struct ksym *)p1)->addr - ((struct ksym *)p2)->addr; +} + +int load_kallsyms(void) +{ + FILE *f; + char func[256], buf[256]; + char symbol; + void *addr; + int i = 0; + + /* + * This is called/used from multiplace places, + * load symbols just once. + */ + if (sym_cnt) + return 0; + + f = fopen("/proc/kallsyms", "r"); + if (!f) + return -ENOENT; + + while (fgets(buf, sizeof(buf), f)) { + if (sscanf(buf, "%p %c %s", &addr, &symbol, func) != 3) + break; + if (!addr) + continue; + syms[i].addr = (long) addr; + syms[i].name = strdup(func); + i++; + } + fclose(f); + sym_cnt = i; + qsort(syms, sym_cnt, sizeof(struct ksym), ksym_cmp); + return 0; +} + +struct ksym *ksym_search(long key) +{ + int start = 0, end = sym_cnt; + int result; + + /* kallsyms not loaded. return NULL */ + if (sym_cnt <= 0) + return NULL; + + while (start < end) { + size_t mid = start + (end - start) / 2; + + result = key - syms[mid].addr; + if (result < 0) + end = mid; + else if (result > 0) + start = mid + 1; + else + return &syms[mid]; + } + + if (start >= 1 && syms[start - 1].addr < key && + key < syms[start].addr) + /* valid ksym */ + return &syms[start - 1]; + + /* out of range. return _stext */ + return &syms[0]; +} + +long ksym_get_addr(const char *name) +{ + int i; + + for (i = 0; i < sym_cnt; i++) { + if (strcmp(syms[i].name, name) == 0) + return syms[i].addr; + } + + return 0; +} + +/* open kallsyms and read symbol addresses on the fly. Without caching all symbols, + * this is faster than load + find. + */ +int kallsyms_find(const char *sym, unsigned long long *addr) +{ + char type, name[500]; + unsigned long long value; + int err = 0; + FILE *f; + + f = fopen("/proc/kallsyms", "r"); + if (!f) + return -EINVAL; + + while (fscanf(f, "%llx %c %499s%*[^\n]\n", &value, &type, name) > 0) { + if (strcmp(name, sym) == 0) { + *addr = value; + goto out; + } + } + err = -ENOENT; + +out: + fclose(f); + return err; +} + +void read_trace_pipe(void) +{ + int trace_fd; + + trace_fd = open(DEBUGFS "trace_pipe", O_RDONLY, 0); + if (trace_fd < 0) + return; + + while (1) { + static char buf[4096]; + ssize_t sz; + + sz = read(trace_fd, buf, sizeof(buf) - 1); + if (sz > 0) { + buf[sz] = 0; + puts(buf); + } + } +} + +ssize_t get_uprobe_offset(const void *addr) +{ + size_t start, end, base; + char buf[256]; + bool found = false; + FILE *f; + + f = fopen("/proc/self/maps", "r"); + if (!f) + return -errno; + + while (fscanf(f, "%zx-%zx %s %zx %*[^\n]\n", &start, &end, buf, &base) == 4) { + if (buf[2] == 'x' && (uintptr_t)addr >= start && (uintptr_t)addr < end) { + found = true; + break; + } + } + + fclose(f); + + if (!found) + return -ESRCH; + +#if defined(__powerpc64__) && defined(_CALL_ELF) && _CALL_ELF == 2 + +#define OP_RT_RA_MASK 0xffff0000UL +#define LIS_R2 0x3c400000UL +#define ADDIS_R2_R12 0x3c4c0000UL +#define ADDI_R2_R2 0x38420000UL + + /* + * A PPC64 ABIv2 function may have a local and a global entry + * point. We need to use the local entry point when patching + * functions, so identify and step over the global entry point + * sequence. + * + * The global entry point sequence is always of the form: + * + * addis r2,r12,XXXX + * addi r2,r2,XXXX + * + * A linker optimisation may convert the addis to lis: + * + * lis r2,XXXX + * addi r2,r2,XXXX + */ + { + const u32 *insn = (const u32 *)(uintptr_t)addr; + + if ((((*insn & OP_RT_RA_MASK) == ADDIS_R2_R12) || + ((*insn & OP_RT_RA_MASK) == LIS_R2)) && + ((*(insn + 1) & OP_RT_RA_MASK) == ADDI_R2_R2)) + return (uintptr_t)(insn + 2) - start + base; + } +#endif + return (uintptr_t)addr - start + base; +} + +ssize_t get_rel_offset(uintptr_t addr) +{ + size_t start, end, offset; + char buf[256]; + FILE *f; + + f = fopen("/proc/self/maps", "r"); + if (!f) + return -errno; + + while (fscanf(f, "%zx-%zx %s %zx %*[^\n]\n", &start, &end, buf, &offset) == 4) { + if (addr >= start && addr < end) { + fclose(f); + return (size_t)addr - start + offset; + } + } + + fclose(f); + return -EINVAL; +} |