tracing/probes: Refactor parse_probe_arg()

Decompose parse_probe_arg() by extracting register, memory/symbol,
dereference, immediate, and default BTF/CPU parsing handlers into
dedicated static helper functions (parse_probe_arg_register,
parse_probe_arg_mem_symbol, parse_probe_arg_deref, parse_probe_arg_imm,
and parse_probe_arg_default). This modularizes the recursive argument
parser and improves readability.

Link: https://lore.kernel.org/all/178399138581.27810.9471730417467607229.stgit@devnote2/

Assisted-by: Antigravity:gemini-3.5-flash
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
This commit is contained in:
Masami Hiramatsu 2026-07-14 10:09:45 +09:00 committed by Masami Hiramatsu (Google)
parent 2590d67a1c
commit 7e79d7fbaf

View File

@ -1516,6 +1516,175 @@ static int __parse_imm_string(char *str, char **pbuf, int offs)
return 0;
}
static int parse_probe_arg_register(char *arg, struct fetch_insn *code,
struct traceprobe_parse_context *ctx)
{
int ret;
if (ctx->flags & (TPARG_FL_TEVENT | TPARG_FL_FPROBE)) {
/* eprobe and fprobe do not handle registers */
trace_probe_log_err(ctx->offset, BAD_VAR);
return -EINVAL;
}
ret = regs_query_register_offset(arg + 1);
if (ret >= 0) {
code->op = FETCH_OP_REG;
code->param = (unsigned int)ret;
return 0;
}
trace_probe_log_err(ctx->offset, BAD_REG_NAME);
return -EINVAL;
}
static int parse_probe_arg_mem_symbol(char *arg, struct fetch_insn **pcode,
struct fetch_insn *end,
struct traceprobe_parse_context *ctx)
{
struct fetch_insn *code = *pcode;
unsigned long param;
long offset = 0;
int ret;
if (isdigit(arg[1])) {
ret = kstrtoul(arg + 1, 0, &param);
if (ret) {
trace_probe_log_err(ctx->offset, BAD_MEM_ADDR);
return ret;
}
/* load address */
code->op = FETCH_OP_IMM;
code->immediate = param;
} else if (arg[1] == '+') {
/* Kernel probes do not support file offsets */
if (ctx->flags & TPARG_FL_KERNEL) {
trace_probe_log_err(ctx->offset, FILE_ON_KPROBE);
return -EINVAL;
}
ret = kstrtol(arg + 2, 0, &offset);
if (ret) {
trace_probe_log_err(ctx->offset, BAD_FILE_OFFS);
return ret;
}
code->op = FETCH_OP_FOFFS;
code->immediate = (unsigned long)offset;
offset = 0;
} else {
/* uprobes don't support symbols */
if (!(ctx->flags & TPARG_FL_KERNEL)) {
trace_probe_log_err(ctx->offset, SYM_ON_UPROBE);
return -EINVAL;
}
/* Preserve symbol for updating */
code->op = FETCH_NOP_SYMBOL;
code->data = kstrdup(arg + 1, GFP_KERNEL);
if (!code->data)
return -ENOMEM;
if (++code == end) {
trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
return -EINVAL;
}
code->op = FETCH_OP_IMM;
code->immediate = 0;
}
/* These are fetching from memory */
if (++code == end) {
trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
return -EINVAL;
}
*pcode = code;
code->op = FETCH_OP_DEREF;
code->offset = offset;
return 0;
}
static int parse_probe_arg_deref(char *arg, struct fetch_insn **pcode,
struct fetch_insn *end,
struct traceprobe_parse_context *ctx)
{
int deref = FETCH_OP_DEREF;
long offset = 0;
char *tmp;
int ret;
if (arg[1] == 'u') {
deref = FETCH_OP_UDEREF;
arg[1] = arg[0];
arg++;
}
if (arg[0] == '+')
arg++; /* Skip '+', because kstrtol() rejects it. */
tmp = strchr(arg, '(');
if (!tmp) {
trace_probe_log_err(ctx->offset, DEREF_NEED_BRACE);
return -EINVAL;
}
*tmp = '\0';
ret = kstrtol(arg, 0, &offset);
if (ret) {
trace_probe_log_err(ctx->offset, BAD_DEREF_OFFS);
return ret;
}
ctx->offset += (tmp + 1 - arg) + (arg[0] != '-' ? 1 : 0);
arg = tmp + 1;
return handle_dereference(arg, pcode, end, ctx, deref, offset);
}
static int parse_probe_arg_imm(char *arg, struct fetch_insn *code,
struct traceprobe_parse_context *ctx)
{
char *tmp;
int ret;
if (arg[1] == '"') { /* Immediate string */
ret = __parse_imm_string(arg + 2, &tmp, ctx->offset + 2);
if (ret)
return ret;
code->op = FETCH_OP_IMMSTR;
code->data = tmp;
} else {
ret = str_to_immediate(arg + 1, &code->immediate);
if (ret) {
trace_probe_log_err(ctx->offset + 1, BAD_IMM);
return ret;
}
code->op = FETCH_OP_IMM;
}
return 0;
}
static int parse_probe_arg_default(char *arg, struct fetch_insn **pcode,
struct fetch_insn *end,
struct traceprobe_parse_context *ctx)
{
int ret;
if (str_has_prefix(arg, THIS_CPU_PTR_PREFIX) ||
str_has_prefix(arg, THIS_CPU_READ_PREFIX)) {
return parse_this_cpu(arg, pcode, end, ctx);
}
if (isalpha(arg[0]) || arg[0] == '_') {
/* BTF variable or event field */
if (ctx->flags & TPARG_FL_TEVENT) {
ret = parse_trace_event(arg, *pcode, ctx);
if (ret < 0) {
trace_probe_log_err(ctx->offset, NO_EVENT_FIELD);
return -EINVAL;
}
return 0;
}
if (!tparg_is_function_entry(ctx->flags) &&
!tparg_is_function_return(ctx->flags)) {
trace_probe_log_err(ctx->offset, NOSUP_BTFARG);
return -EINVAL;
}
return parse_btf_arg(arg, pcode, end, ctx);
}
return 0;
}
/* Recursive argument parser */
static int
parse_probe_arg(char *arg, const struct fetch_type *type,
@ -1523,151 +1692,30 @@ parse_probe_arg(char *arg, const struct fetch_type *type,
struct traceprobe_parse_context *ctx)
{
struct fetch_insn *code = *pcode;
unsigned long param;
int deref = FETCH_OP_DEREF;
long offset = 0;
char *tmp;
int ret = 0;
int ret;
switch (arg[0]) {
case '$':
ret = parse_probe_vars(arg, type, pcode, end, ctx);
break;
case '%': /* named register */
if (ctx->flags & (TPARG_FL_TEVENT | TPARG_FL_FPROBE)) {
/* eprobe and fprobe do not handle registers */
trace_probe_log_err(ctx->offset, BAD_VAR);
break;
}
ret = regs_query_register_offset(arg + 1);
if (ret >= 0) {
code->op = FETCH_OP_REG;
code->param = (unsigned int)ret;
ret = 0;
} else
trace_probe_log_err(ctx->offset, BAD_REG_NAME);
ret = parse_probe_arg_register(arg, code, ctx);
break;
case '@': /* memory, file-offset or symbol */
if (isdigit(arg[1])) {
ret = kstrtoul(arg + 1, 0, &param);
if (ret) {
trace_probe_log_err(ctx->offset, BAD_MEM_ADDR);
break;
}
/* load address */
code->op = FETCH_OP_IMM;
code->immediate = param;
} else if (arg[1] == '+') {
/* Kernel probes do not support file offsets */
if (ctx->flags & TPARG_FL_KERNEL) {
trace_probe_log_err(ctx->offset, FILE_ON_KPROBE);
return -EINVAL;
}
ret = kstrtol(arg + 2, 0, &offset);
if (ret) {
trace_probe_log_err(ctx->offset, BAD_FILE_OFFS);
break;
}
code->op = FETCH_OP_FOFFS;
code->immediate = (unsigned long)offset; // imm64?
offset = 0;
} else {
/* uprobes don't support symbols */
if (!(ctx->flags & TPARG_FL_KERNEL)) {
trace_probe_log_err(ctx->offset, SYM_ON_UPROBE);
return -EINVAL;
}
/* Preserve symbol for updating */
code->op = FETCH_NOP_SYMBOL;
code->data = kstrdup(arg + 1, GFP_KERNEL);
if (!code->data)
return -ENOMEM;
if (++code == end) {
trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
return -EINVAL;
}
code->op = FETCH_OP_IMM;
code->immediate = 0;
}
/* These are fetching from memory */
if (++code == end) {
trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
return -EINVAL;
}
*pcode = code;
code->op = FETCH_OP_DEREF;
code->offset = offset;
ret = parse_probe_arg_mem_symbol(arg, pcode, end, ctx);
break;
case '+': /* deref memory */
case '-':
if (arg[1] == 'u') {
deref = FETCH_OP_UDEREF;
arg[1] = arg[0];
arg++;
}
if (arg[0] == '+')
arg++; /* Skip '+', because kstrtol() rejects it. */
tmp = strchr(arg, '(');
if (!tmp) {
trace_probe_log_err(ctx->offset, DEREF_NEED_BRACE);
return -EINVAL;
}
*tmp = '\0';
ret = kstrtol(arg, 0, &offset);
if (ret) {
trace_probe_log_err(ctx->offset, BAD_DEREF_OFFS);
break;
}
ctx->offset += (tmp + 1 - arg) + (arg[0] != '-' ? 1 : 0);
arg = tmp + 1;
ret = handle_dereference(arg, pcode, end, ctx, deref, offset);
if (ret < 0)
return ret;
ret = parse_probe_arg_deref(arg, pcode, end, ctx);
break;
case '\\': /* Immediate value */
if (arg[1] == '"') { /* Immediate string */
ret = __parse_imm_string(arg + 2, &tmp, ctx->offset + 2);
if (ret)
break;
code->op = FETCH_OP_IMMSTR;
code->data = tmp;
} else {
ret = str_to_immediate(arg + 1, &code->immediate);
if (ret)
trace_probe_log_err(ctx->offset + 1, BAD_IMM);
else
code->op = FETCH_OP_IMM;
}
ret = parse_probe_arg_imm(arg, code, ctx);
break;
case '(':
ret = handle_typecast(arg, pcode, end, ctx);
break;
default:
if (str_has_prefix(arg, THIS_CPU_PTR_PREFIX) ||
str_has_prefix(arg, THIS_CPU_READ_PREFIX)) {
ret = parse_this_cpu(arg, pcode, end, ctx);
} else if (isalpha(arg[0]) || arg[0] == '_') {
/* BTF variable or event field*/
if (ctx->flags & TPARG_FL_TEVENT) {
ret = parse_trace_event(arg, *pcode, ctx);
if (ret < 0) {
trace_probe_log_err(ctx->offset,
NO_EVENT_FIELD);
return -EINVAL;
}
break;
}
if (!tparg_is_function_entry(ctx->flags) &&
!tparg_is_function_return(ctx->flags)) {
trace_probe_log_err(ctx->offset, NOSUP_BTFARG);
return -EINVAL;
}
ret = parse_btf_arg(arg, pcode, end, ctx);
}
ret = parse_probe_arg_default(arg, pcode, end, ctx);
break;
}
if (!ret && code->op == FETCH_OP_NOP) {