diff options
| -rw-r--r-- | tools/lib/bpf/usdt.c | 105 |
1 files changed, 105 insertions, 0 deletions
diff --git a/tools/lib/bpf/usdt.c b/tools/lib/bpf/usdt.c index 2799387c5465..1bce2eab5e89 100644 --- a/tools/lib/bpf/usdt.c +++ b/tools/lib/bpf/usdt.c @@ -1168,8 +1168,113 @@ static int parse_usdt_spec(struct usdt_spec *spec, const struct usdt_note *note, return 0; } +/* Architecture-specific logic for parsing USDT argument location specs */ + +#if defined(__x86_64__) || defined(__i386__) + +static int calc_pt_regs_off(const char *reg_name) +{ + static struct { + const char *names[4]; + size_t pt_regs_off; + } reg_map[] = { +#if __x86_64__ +#define reg_off(reg64, reg32) offsetof(struct pt_regs, reg64) +#else +#define reg_off(reg64, reg32) offsetof(struct pt_regs, reg32) +#endif + { {"rip", "eip", "", ""}, reg_off(rip, eip) }, + { {"rax", "eax", "ax", "al"}, reg_off(rax, eax) }, + { {"rbx", "ebx", "bx", "bl"}, reg_off(rbx, ebx) }, + { {"rcx", "ecx", "cx", "cl"}, reg_off(rcx, ecx) }, + { {"rdx", "edx", "dx", "dl"}, reg_off(rdx, edx) }, + { {"rsi", "esi", "si", "sil"}, reg_off(rsi, esi) }, + { {"rdi", "edi", "di", "dil"}, reg_off(rdi, edi) }, + { {"rbp", "ebp", "bp", "bpl"}, reg_off(rbp, ebp) }, + { {"rsp", "esp", "sp", "spl"}, reg_off(rsp, esp) }, +#undef reg_off +#if __x86_64__ + { {"r8", "r8d", "r8w", "r8b"}, offsetof(struct pt_regs, r8) }, + { {"r9", "r9d", "r9w", "r9b"}, offsetof(struct pt_regs, r9) }, + { {"r10", "r10d", "r10w", "r10b"}, offsetof(struct pt_regs, r10) }, + { {"r11", "r11d", "r11w", "r11b"}, offsetof(struct pt_regs, r11) }, + { {"r12", "r12d", "r12w", "r12b"}, offsetof(struct pt_regs, r12) }, + { {"r13", "r13d", "r13w", "r13b"}, offsetof(struct pt_regs, r13) }, + { {"r14", "r14d", "r14w", "r14b"}, offsetof(struct pt_regs, r14) }, + { {"r15", "r15d", "r15w", "r15b"}, offsetof(struct pt_regs, r15) }, +#endif + }; + int i, j; + + for (i = 0; i < ARRAY_SIZE(reg_map); i++) { + for (j = 0; j < ARRAY_SIZE(reg_map[i].names); j++) { + if (strcmp(reg_name, reg_map[i].names[j]) == 0) + return reg_map[i].pt_regs_off; + } + } + + pr_warn("usdt: unrecognized register '%s'\n", reg_name); + return -ENOENT; +} + +static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec *arg) +{ + char *reg_name = NULL; + int arg_sz, len, reg_off; + long off; + + if (sscanf(arg_str, " %d @ %ld ( %%%m[^)] ) %n", &arg_sz, &off, ®_name, &len) == 3) { + /* Memory dereference case, e.g., -4@-20(%rbp) */ + arg->arg_type = USDT_ARG_REG_DEREF; + arg->val_off = off; + reg_off = calc_pt_regs_off(reg_name); + free(reg_name); + if (reg_off < 0) + return reg_off; + arg->reg_off = reg_off; + } else if (sscanf(arg_str, " %d @ %%%ms %n", &arg_sz, ®_name, &len) == 2) { + /* Register read case, e.g., -4@%eax */ + arg->arg_type = USDT_ARG_REG; + arg->val_off = 0; + + reg_off = calc_pt_regs_off(reg_name); + free(reg_name); + if (reg_off < 0) + return reg_off; + arg->reg_off = reg_off; + } else if (sscanf(arg_str, " %d @ $%ld %n", &arg_sz, &off, &len) == 2) { + /* Constant value case, e.g., 4@$71 */ + arg->arg_type = USDT_ARG_CONST; + arg->val_off = off; + arg->reg_off = 0; + } else { + pr_warn("usdt: unrecognized arg #%d spec '%s'\n", arg_num, arg_str); + return -EINVAL; + } + + arg->arg_signed = arg_sz < 0; + if (arg_sz < 0) + arg_sz = -arg_sz; + + switch (arg_sz) { + case 1: case 2: case 4: case 8: + arg->arg_bitshift = 64 - arg_sz * 8; + break; + default: + pr_warn("usdt: unsupported arg #%d (spec '%s') size: %d\n", + arg_num, arg_str, arg_sz); + return -EINVAL; + } + + return len; +} + +#else + static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec *arg) { pr_warn("usdt: libbpf doesn't support USDTs on current architecture\n"); return -ENOTSUP; } + +#endif |