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authorMasami Hiramatsu <mhiramat@kernel.org>2018-04-25 21:18:03 +0900
committerSteven Rostedt (VMware) <rostedt@goodmis.org>2018-10-10 22:19:07 -0400
commit533059281ee594f9fbb9e58042aaec77083ef251 (patch)
tree92019727bc72f3253f5e9de7152ced000cc4f27b /kernel/trace/trace_probe.c
parent7bfbc63eda08b8158c040d6882c807f62b0750bb (diff)
tracing: probeevent: Introduce new argument fetching code
Replace {k,u}probe event argument fetching framework with switch-case based. Currently that is implemented with structures, macros and chain of function-pointers, which is more complicated than necessary and may get a performance penalty by retpoline. This simplify that with an array of "fetch_insn" (opcode and oprands), and make process_fetch_insn() just interprets it. No function pointers are used. Link: http://lkml.kernel.org/r/152465868340.26224.2551120475197839464.stgit@devbox Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace/trace_probe.c')
-rw-r--r--kernel/trace/trace_probe.c401
1 files changed, 112 insertions, 289 deletions
diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
index 5f3b5b3fd2cd..c59c69cb2f2e 100644
--- a/kernel/trace/trace_probe.c
+++ b/kernel/trace/trace_probe.c
@@ -61,174 +61,6 @@ int PRINT_TYPE_FUNC_NAME(string)(struct trace_seq *s, void *data, void *ent)
const char PRINT_TYPE_FMT_NAME(string)[] = "\\\"%s\\\"";
-#define CHECK_FETCH_FUNCS(method, fn) \
- (((FETCH_FUNC_NAME(method, u8) == fn) || \
- (FETCH_FUNC_NAME(method, u16) == fn) || \
- (FETCH_FUNC_NAME(method, u32) == fn) || \
- (FETCH_FUNC_NAME(method, u64) == fn) || \
- (FETCH_FUNC_NAME(method, string) == fn) || \
- (FETCH_FUNC_NAME(method, string_size) == fn)) \
- && (fn != NULL))
-
-/* Data fetch function templates */
-#define DEFINE_FETCH_reg(type) \
-void FETCH_FUNC_NAME(reg, type)(struct pt_regs *regs, void *offset, void *dest) \
-{ \
- *(type *)dest = (type)regs_get_register(regs, \
- (unsigned int)((unsigned long)offset)); \
-} \
-NOKPROBE_SYMBOL(FETCH_FUNC_NAME(reg, type));
-DEFINE_BASIC_FETCH_FUNCS(reg)
-/* No string on the register */
-#define fetch_reg_string NULL
-#define fetch_reg_string_size NULL
-
-#define DEFINE_FETCH_retval(type) \
-void FETCH_FUNC_NAME(retval, type)(struct pt_regs *regs, \
- void *dummy, void *dest) \
-{ \
- *(type *)dest = (type)regs_return_value(regs); \
-} \
-NOKPROBE_SYMBOL(FETCH_FUNC_NAME(retval, type));
-DEFINE_BASIC_FETCH_FUNCS(retval)
-/* No string on the retval */
-#define fetch_retval_string NULL
-#define fetch_retval_string_size NULL
-
-/* Dereference memory access function */
-struct deref_fetch_param {
- struct fetch_param orig;
- long offset;
- fetch_func_t fetch;
- fetch_func_t fetch_size;
-};
-
-#define DEFINE_FETCH_deref(type) \
-void FETCH_FUNC_NAME(deref, type)(struct pt_regs *regs, \
- void *data, void *dest) \
-{ \
- struct deref_fetch_param *dprm = data; \
- unsigned long addr; \
- call_fetch(&dprm->orig, regs, &addr); \
- if (addr) { \
- addr += dprm->offset; \
- dprm->fetch(regs, (void *)addr, dest); \
- } else \
- *(type *)dest = 0; \
-} \
-NOKPROBE_SYMBOL(FETCH_FUNC_NAME(deref, type));
-DEFINE_BASIC_FETCH_FUNCS(deref)
-DEFINE_FETCH_deref(string)
-
-void FETCH_FUNC_NAME(deref, string_size)(struct pt_regs *regs,
- void *data, void *dest)
-{
- struct deref_fetch_param *dprm = data;
- unsigned long addr;
-
- call_fetch(&dprm->orig, regs, &addr);
- if (addr && dprm->fetch_size) {
- addr += dprm->offset;
- dprm->fetch_size(regs, (void *)addr, dest);
- } else
- *(string_size *)dest = 0;
-}
-NOKPROBE_SYMBOL(FETCH_FUNC_NAME(deref, string_size));
-
-static void update_deref_fetch_param(struct deref_fetch_param *data)
-{
- if (CHECK_FETCH_FUNCS(deref, data->orig.fn))
- update_deref_fetch_param(data->orig.data);
- else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn))
- update_symbol_cache(data->orig.data);
-}
-NOKPROBE_SYMBOL(update_deref_fetch_param);
-
-static void free_deref_fetch_param(struct deref_fetch_param *data)
-{
- if (CHECK_FETCH_FUNCS(deref, data->orig.fn))
- free_deref_fetch_param(data->orig.data);
- else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn))
- free_symbol_cache(data->orig.data);
- kfree(data);
-}
-NOKPROBE_SYMBOL(free_deref_fetch_param);
-
-/* Bitfield fetch function */
-struct bitfield_fetch_param {
- struct fetch_param orig;
- unsigned char hi_shift;
- unsigned char low_shift;
-};
-
-#define DEFINE_FETCH_bitfield(type) \
-void FETCH_FUNC_NAME(bitfield, type)(struct pt_regs *regs, \
- void *data, void *dest) \
-{ \
- struct bitfield_fetch_param *bprm = data; \
- type buf = 0; \
- call_fetch(&bprm->orig, regs, &buf); \
- if (buf) { \
- buf <<= bprm->hi_shift; \
- buf >>= bprm->low_shift; \
- } \
- *(type *)dest = buf; \
-} \
-NOKPROBE_SYMBOL(FETCH_FUNC_NAME(bitfield, type));
-DEFINE_BASIC_FETCH_FUNCS(bitfield)
-#define fetch_bitfield_string NULL
-#define fetch_bitfield_string_size NULL
-
-static void
-update_bitfield_fetch_param(struct bitfield_fetch_param *data)
-{
- /*
- * Don't check the bitfield itself, because this must be the
- * last fetch function.
- */
- if (CHECK_FETCH_FUNCS(deref, data->orig.fn))
- update_deref_fetch_param(data->orig.data);
- else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn))
- update_symbol_cache(data->orig.data);
-}
-
-static void
-free_bitfield_fetch_param(struct bitfield_fetch_param *data)
-{
- /*
- * Don't check the bitfield itself, because this must be the
- * last fetch function.
- */
- if (CHECK_FETCH_FUNCS(deref, data->orig.fn))
- free_deref_fetch_param(data->orig.data);
- else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn))
- free_symbol_cache(data->orig.data);
-
- kfree(data);
-}
-
-void FETCH_FUNC_NAME(comm, string)(struct pt_regs *regs,
- void *data, void *dest)
-{
- int maxlen = get_rloc_len(*(u32 *)dest);
- u8 *dst = get_rloc_data(dest);
- long ret;
-
- if (!maxlen)
- return;
-
- ret = strlcpy(dst, current->comm, maxlen);
- *(u32 *)dest = make_data_rloc(ret, get_rloc_offs(*(u32 *)dest));
-}
-NOKPROBE_SYMBOL(FETCH_FUNC_NAME(comm, string));
-
-void FETCH_FUNC_NAME(comm, string_size)(struct pt_regs *regs,
- void *data, void *dest)
-{
- *(u32 *)dest = strlen(current->comm) + 1;
-}
-NOKPROBE_SYMBOL(FETCH_FUNC_NAME(comm, string_size));
-
static const struct fetch_type *find_fetch_type(const char *type,
const struct fetch_type *ftbl)
{
@@ -272,37 +104,6 @@ fail:
return NULL;
}
-/* Special function : only accept unsigned long */
-static void fetch_kernel_stack_address(struct pt_regs *regs, void *dummy, void *dest)
-{
- *(unsigned long *)dest = kernel_stack_pointer(regs);
-}
-NOKPROBE_SYMBOL(fetch_kernel_stack_address);
-
-static void fetch_user_stack_address(struct pt_regs *regs, void *dummy, void *dest)
-{
- *(unsigned long *)dest = user_stack_pointer(regs);
-}
-NOKPROBE_SYMBOL(fetch_user_stack_address);
-
-static fetch_func_t get_fetch_size_function(const struct fetch_type *type,
- fetch_func_t orig_fn,
- const struct fetch_type *ftbl)
-{
- int i;
-
- if (type != &ftbl[FETCH_TYPE_STRING])
- return NULL; /* Only string type needs size function */
-
- for (i = 0; i < FETCH_MTD_END; i++)
- if (type->fetch[i] == orig_fn)
- return ftbl[FETCH_TYPE_STRSIZE].fetch[i];
-
- WARN_ON(1); /* This should not happen */
-
- return NULL;
-}
-
/* Split symbol and offset. */
int traceprobe_split_symbol_offset(char *symbol, long *offset)
{
@@ -327,7 +128,7 @@ int traceprobe_split_symbol_offset(char *symbol, long *offset)
#define PARAM_MAX_STACK (THREAD_SIZE / sizeof(unsigned long))
static int parse_probe_vars(char *arg, const struct fetch_type *t,
- struct fetch_param *f, bool is_return,
+ struct fetch_insn *code, bool is_return,
bool is_kprobe)
{
int ret = 0;
@@ -335,33 +136,24 @@ static int parse_probe_vars(char *arg, const struct fetch_type *t,
if (strcmp(arg, "retval") == 0) {
if (is_return)
- f->fn = t->fetch[FETCH_MTD_retval];
+ code->op = FETCH_OP_RETVAL;
else
ret = -EINVAL;
} else if (strncmp(arg, "stack", 5) == 0) {
if (arg[5] == '\0') {
- if (strcmp(t->name, DEFAULT_FETCH_TYPE_STR))
- return -EINVAL;
-
- if (is_kprobe)
- f->fn = fetch_kernel_stack_address;
- else
- f->fn = fetch_user_stack_address;
+ code->op = FETCH_OP_STACKP;
} else if (isdigit(arg[5])) {
ret = kstrtoul(arg + 5, 10, &param);
if (ret || (is_kprobe && param > PARAM_MAX_STACK))
ret = -EINVAL;
else {
- f->fn = t->fetch[FETCH_MTD_stack];
- f->data = (void *)param;
+ code->op = FETCH_OP_STACK;
+ code->param = (unsigned int)param;
}
} else
ret = -EINVAL;
} else if (strcmp(arg, "comm") == 0) {
- if (strcmp(t->name, "string") != 0 &&
- strcmp(t->name, "string_size") != 0)
- return -EINVAL;
- f->fn = t->fetch[FETCH_MTD_comm];
+ code->op = FETCH_OP_COMM;
} else
ret = -EINVAL;
@@ -369,10 +161,13 @@ static int parse_probe_vars(char *arg, const struct fetch_type *t,
}
/* Recursive argument parser */
-static int parse_probe_arg(char *arg, const struct fetch_type *t,
- struct fetch_param *f, bool is_return, bool is_kprobe,
- const struct fetch_type *ftbl)
+static int
+parse_probe_arg(char *arg, const struct fetch_type *type,
+ struct fetch_insn **pcode, struct fetch_insn *end,
+ bool is_return, bool is_kprobe,
+ const struct fetch_type *ftbl)
{
+ struct fetch_insn *code = *pcode;
unsigned long param;
long offset;
char *tmp;
@@ -380,14 +175,15 @@ static int parse_probe_arg(char *arg, const struct fetch_type *t,
switch (arg[0]) {
case '$':
- ret = parse_probe_vars(arg + 1, t, f, is_return, is_kprobe);
+ ret = parse_probe_vars(arg + 1, type, code,
+ is_return, is_kprobe);
break;
case '%': /* named register */
ret = regs_query_register_offset(arg + 1);
if (ret >= 0) {
- f->fn = t->fetch[FETCH_MTD_reg];
- f->data = (void *)(unsigned long)ret;
+ code->op = FETCH_OP_REG;
+ code->param = (unsigned int)ret;
ret = 0;
}
break;
@@ -397,9 +193,9 @@ static int parse_probe_arg(char *arg, const struct fetch_type *t,
ret = kstrtoul(arg + 1, 0, &param);
if (ret)
break;
-
- f->fn = t->fetch[FETCH_MTD_memory];
- f->data = (void *)param;
+ /* load address */
+ code->op = FETCH_OP_IMM;
+ code->immediate = param;
} else if (arg[1] == '+') {
/* kprobes don't support file offsets */
if (is_kprobe)
@@ -409,8 +205,8 @@ static int parse_probe_arg(char *arg, const struct fetch_type *t,
if (ret)
break;
- f->fn = t->fetch[FETCH_MTD_file_offset];
- f->data = (void *)offset;
+ code->op = FETCH_OP_FOFFS;
+ code->immediate = (unsigned long)offset; // imm64?
} else {
/* uprobes don't support symbols */
if (!is_kprobe)
@@ -420,10 +216,19 @@ static int parse_probe_arg(char *arg, const struct fetch_type *t,
if (ret)
break;
- f->data = alloc_symbol_cache(arg + 1, offset);
- if (f->data)
- f->fn = t->fetch[FETCH_MTD_symbol];
+ code->op = FETCH_OP_IMM;
+ code->immediate =
+ (unsigned long)kallsyms_lookup_name(arg + 1);
+ if (!code->immediate)
+ return -ENOENT;
+ code->immediate += offset;
}
+ /* These are fetching from memory */
+ if (++code == end)
+ return -E2BIG;
+ *pcode = code;
+ code->op = FETCH_OP_DEREF;
+ code->offset = offset;
break;
case '+': /* deref memory */
@@ -431,11 +236,10 @@ static int parse_probe_arg(char *arg, const struct fetch_type *t,
case '-':
tmp = strchr(arg, '(');
if (!tmp)
- break;
+ return -EINVAL;
*tmp = '\0';
ret = kstrtol(arg, 0, &offset);
-
if (ret)
break;
@@ -443,36 +247,29 @@ static int parse_probe_arg(char *arg, const struct fetch_type *t,
tmp = strrchr(arg, ')');
if (tmp) {
- struct deref_fetch_param *dprm;
- const struct fetch_type *t2;
+ const struct fetch_type *t2;
t2 = find_fetch_type(NULL, ftbl);
*tmp = '\0';
- dprm = kzalloc(sizeof(struct deref_fetch_param), GFP_KERNEL);
-
- if (!dprm)
- return -ENOMEM;
-
- dprm->offset = offset;
- dprm->fetch = t->fetch[FETCH_MTD_memory];
- dprm->fetch_size = get_fetch_size_function(t,
- dprm->fetch, ftbl);
- ret = parse_probe_arg(arg, t2, &dprm->orig, is_return,
- is_kprobe, ftbl);
+ ret = parse_probe_arg(arg, t2, &code, end, is_return,
+ is_kprobe, ftbl);
if (ret)
- kfree(dprm);
- else {
- f->fn = t->fetch[FETCH_MTD_deref];
- f->data = (void *)dprm;
- }
+ break;
+ if (code->op == FETCH_OP_COMM)
+ return -EINVAL;
+ if (++code == end)
+ return -E2BIG;
+ *pcode = code;
+
+ code->op = FETCH_OP_DEREF;
+ code->offset = offset;
}
break;
}
- if (!ret && !f->fn) { /* Parsed, but do not find fetch method */
- pr_info("%s type has no corresponding fetch method.\n", t->name);
+ if (!ret && code->op == FETCH_OP_NOP) {
+ /* Parsed, but do not find fetch method */
ret = -EINVAL;
}
-
return ret;
}
@@ -481,22 +278,15 @@ static int parse_probe_arg(char *arg, const struct fetch_type *t,
/* Bitfield type needs to be parsed into a fetch function */
static int __parse_bitfield_probe_arg(const char *bf,
const struct fetch_type *t,
- struct fetch_param *f)
+ struct fetch_insn **pcode)
{
- struct bitfield_fetch_param *bprm;
+ struct fetch_insn *code = *pcode;
unsigned long bw, bo;
char *tail;
if (*bf != 'b')
return 0;
- bprm = kzalloc(sizeof(*bprm), GFP_KERNEL);
- if (!bprm)
- return -ENOMEM;
-
- bprm->orig = *f;
- f->fn = t->fetch[FETCH_MTD_bitfield];
- f->data = (void *)bprm;
bw = simple_strtoul(bf + 1, &tail, 0); /* Use simple one */
if (bw == 0 || *tail != '@')
@@ -507,9 +297,15 @@ static int __parse_bitfield_probe_arg(const char *bf,
if (tail == bf || *tail != '/')
return -EINVAL;
+ code++;
+ if (code->op != FETCH_OP_NOP)
+ return -E2BIG;
+ *pcode = code;
- bprm->hi_shift = BYTES_TO_BITS(t->size) - (bw + bo);
- bprm->low_shift = bprm->hi_shift + bo;
+ code->op = FETCH_OP_MOD_BF;
+ code->lshift = BYTES_TO_BITS(t->size) - (bw + bo);
+ code->rshift = BYTES_TO_BITS(t->size) - bw;
+ code->basesize = t->size;
return (BYTES_TO_BITS(t->size) < (bw + bo)) ? -EINVAL : 0;
}
@@ -519,6 +315,7 @@ int traceprobe_parse_probe_arg(char *arg, ssize_t *size,
struct probe_arg *parg, bool is_return, bool is_kprobe,
const struct fetch_type *ftbl)
{
+ struct fetch_insn *code, *tmp = NULL;
const char *t;
int ret;
@@ -549,18 +346,60 @@ int traceprobe_parse_probe_arg(char *arg, ssize_t *size,
}
parg->offset = *size;
*size += parg->type->size;
- ret = parse_probe_arg(arg, parg->type, &parg->fetch, is_return,
- is_kprobe, ftbl);
-
- if (ret >= 0 && t != NULL)
- ret = __parse_bitfield_probe_arg(t, parg->type, &parg->fetch);
- if (ret >= 0) {
- parg->fetch_size.fn = get_fetch_size_function(parg->type,
- parg->fetch.fn,
- ftbl);
- parg->fetch_size.data = parg->fetch.data;
+ code = tmp = kzalloc(sizeof(*code) * FETCH_INSN_MAX, GFP_KERNEL);
+ if (!code)
+ return -ENOMEM;
+ code[FETCH_INSN_MAX - 1].op = FETCH_OP_END;
+
+ ret = parse_probe_arg(arg, parg->type, &code, &code[FETCH_INSN_MAX - 1],
+ is_return, is_kprobe, ftbl);
+ if (ret)
+ goto fail;
+
+ /* Store operation */
+ if (!strcmp(parg->type->name, "string")) {
+ if (code->op != FETCH_OP_DEREF && code->op != FETCH_OP_IMM &&
+ code->op != FETCH_OP_COMM) {
+ pr_info("string only accepts memory or address.\n");
+ ret = -EINVAL;
+ goto fail;
+ }
+ /* Since IMM or COMM must be the 1st insn, this is safe */
+ if (code->op == FETCH_OP_IMM || code->op == FETCH_OP_COMM)
+ code++;
+ code->op = FETCH_OP_ST_STRING; /* In DEREF case, replace it */
+ parg->dynamic = true;
+ } else if (code->op == FETCH_OP_DEREF) {
+ code->op = FETCH_OP_ST_MEM;
+ code->size = parg->type->size;
+ } else {
+ code++;
+ if (code->op != FETCH_OP_NOP) {
+ ret = -E2BIG;
+ goto fail;
+ }
+ code->op = FETCH_OP_ST_RAW;
+ code->size = parg->type->size;
+ }
+ /* Modify operation */
+ if (t != NULL) {
+ ret = __parse_bitfield_probe_arg(t, parg->type, &code);
+ if (ret)
+ goto fail;
}
+ code++;
+ code->op = FETCH_OP_END;
+
+ /* Shrink down the code buffer */
+ parg->code = kzalloc(sizeof(*code) * (code - tmp + 1), GFP_KERNEL);
+ if (!parg->code)
+ ret = -ENOMEM;
+ else
+ memcpy(parg->code, tmp, sizeof(*code) * (code - tmp + 1));
+
+fail:
+ kfree(tmp);
return ret;
}
@@ -582,25 +421,9 @@ int traceprobe_conflict_field_name(const char *name,
return 0;
}
-void traceprobe_update_arg(struct probe_arg *arg)
-{
- if (CHECK_FETCH_FUNCS(bitfield, arg->fetch.fn))
- update_bitfield_fetch_param(arg->fetch.data);
- else if (CHECK_FETCH_FUNCS(deref, arg->fetch.fn))
- update_deref_fetch_param(arg->fetch.data);
- else if (CHECK_FETCH_FUNCS(symbol, arg->fetch.fn))
- update_symbol_cache(arg->fetch.data);
-}
-
void traceprobe_free_probe_arg(struct probe_arg *arg)
{
- if (CHECK_FETCH_FUNCS(bitfield, arg->fetch.fn))
- free_bitfield_fetch_param(arg->fetch.data);
- else if (CHECK_FETCH_FUNCS(deref, arg->fetch.fn))
- free_deref_fetch_param(arg->fetch.data);
- else if (CHECK_FETCH_FUNCS(symbol, arg->fetch.fn))
- free_symbol_cache(arg->fetch.data);
-
+ kfree(arg->code);
kfree(arg->name);
kfree(arg->comm);
}