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/* SPDX-License-Identifier: GPL-2.0 */
/*
* Traceprobe fetch helper inlines
*/
static nokprobe_inline void
fetch_store_raw(unsigned long val, struct fetch_insn *code, void *buf)
{
switch (code->size) {
case 1:
*(u8 *)buf = (u8)val;
break;
case 2:
*(u16 *)buf = (u16)val;
break;
case 4:
*(u32 *)buf = (u32)val;
break;
case 8:
//TBD: 32bit signed
*(u64 *)buf = (u64)val;
break;
default:
*(unsigned long *)buf = val;
}
}
static nokprobe_inline void
fetch_apply_bitfield(struct fetch_insn *code, void *buf)
{
switch (code->basesize) {
case 1:
*(u8 *)buf <<= code->lshift;
*(u8 *)buf >>= code->rshift;
break;
case 2:
*(u16 *)buf <<= code->lshift;
*(u16 *)buf >>= code->rshift;
break;
case 4:
*(u32 *)buf <<= code->lshift;
*(u32 *)buf >>= code->rshift;
break;
case 8:
*(u64 *)buf <<= code->lshift;
*(u64 *)buf >>= code->rshift;
break;
}
}
/*
* These functions must be defined for each callsite.
* Return consumed dynamic data size (>= 0), or error (< 0).
* If dest is NULL, don't store result and return required dynamic data size.
*/
static int
process_fetch_insn(struct fetch_insn *code, void *rec,
void *dest, void *base);
static nokprobe_inline int fetch_store_strlen(unsigned long addr);
static nokprobe_inline int
fetch_store_string(unsigned long addr, void *dest, void *base);
static nokprobe_inline int fetch_store_strlen_user(unsigned long addr);
static nokprobe_inline int
fetch_store_string_user(unsigned long addr, void *dest, void *base);
static nokprobe_inline int
probe_mem_read(void *dest, void *src, size_t size);
static nokprobe_inline int
probe_mem_read_user(void *dest, void *src, size_t size);
static nokprobe_inline int
fetch_store_symstrlen(unsigned long addr)
{
char namebuf[KSYM_SYMBOL_LEN];
int ret;
ret = sprint_symbol(namebuf, addr);
if (ret < 0)
return 0;
return ret + 1;
}
/*
* Fetch a null-terminated symbol string + offset. Caller MUST set *(u32 *)buf
* with max length and relative data location.
*/
static nokprobe_inline int
fetch_store_symstring(unsigned long addr, void *dest, void *base)
{
int maxlen = get_loc_len(*(u32 *)dest);
void *__dest;
if (unlikely(!maxlen))
return -ENOMEM;
__dest = get_loc_data(dest, base);
return sprint_symbol(__dest, addr);
}
/* common part of process_fetch_insn*/
static nokprobe_inline int
process_common_fetch_insn(struct fetch_insn *code, unsigned long *val)
{
switch (code->op) {
case FETCH_OP_IMM:
*val = code->immediate;
break;
case FETCH_OP_COMM:
*val = (unsigned long)current->comm;
break;
case FETCH_OP_DATA:
*val = (unsigned long)code->data;
break;
default:
return -EILSEQ;
}
return 0;
}
/* From the 2nd stage, routine is same */
static nokprobe_inline int
process_fetch_insn_bottom(struct fetch_insn *code, unsigned long val,
void *dest, void *base)
{
struct fetch_insn *s3 = NULL;
int total = 0, ret = 0, i = 0;
u32 loc = 0;
unsigned long lval = val;
stage2:
/* 2nd stage: dereference memory if needed */
do {
if (code->op == FETCH_OP_DEREF) {
lval = val;
ret = probe_mem_read(&val, (void *)val + code->offset,
sizeof(val));
} else if (code->op == FETCH_OP_UDEREF) {
lval = val;
ret = probe_mem_read_user(&val,
(void *)val + code->offset, sizeof(val));
} else
break;
if (ret)
return ret;
code++;
} while (1);
s3 = code;
stage3:
/* 3rd stage: store value to buffer */
if (unlikely(!dest)) {
switch (code->op) {
case FETCH_OP_ST_STRING:
ret = fetch_store_strlen(val + code->offset);
code++;
goto array;
case FETCH_OP_ST_USTRING:
ret = fetch_store_strlen_user(val + code->offset);
code++;
goto array;
case FETCH_OP_ST_SYMSTR:
ret = fetch_store_symstrlen(val + code->offset);
code++;
goto array;
default:
return -EILSEQ;
}
}
switch (code->op) {
case FETCH_OP_ST_RAW:
fetch_store_raw(val, code, dest);
break;
case FETCH_OP_ST_MEM:
probe_mem_read(dest, (void *)val + code->offset, code->size);
break;
case FETCH_OP_ST_UMEM:
probe_mem_read_user(dest, (void *)val + code->offset, code->size);
break;
case FETCH_OP_ST_STRING:
loc = *(u32 *)dest;
ret = fetch_store_string(val + code->offset, dest, base);
break;
case FETCH_OP_ST_USTRING:
loc = *(u32 *)dest;
ret = fetch_store_string_user(val + code->offset, dest, base);
break;
case FETCH_OP_ST_SYMSTR:
loc = *(u32 *)dest;
ret = fetch_store_symstring(val + code->offset, dest, base);
break;
default:
return -EILSEQ;
}
code++;
/* 4th stage: modify stored value if needed */
if (code->op == FETCH_OP_MOD_BF) {
fetch_apply_bitfield(code, dest);
code++;
}
array:
/* the last stage: Loop on array */
if (code->op == FETCH_OP_LP_ARRAY) {
total += ret;
if (++i < code->param) {
code = s3;
if (s3->op != FETCH_OP_ST_STRING &&
s3->op != FETCH_OP_ST_USTRING) {
dest += s3->size;
val += s3->size;
goto stage3;
}
code--;
val = lval + sizeof(char *);
if (dest) {
dest += sizeof(u32);
*(u32 *)dest = update_data_loc(loc, ret);
}
goto stage2;
}
code++;
ret = total;
}
return code->op == FETCH_OP_END ? ret : -EILSEQ;
}
/* Sum up total data length for dynamic arrays (strings) */
static nokprobe_inline int
__get_data_size(struct trace_probe *tp, struct pt_regs *regs)
{
struct probe_arg *arg;
int i, len, ret = 0;
for (i = 0; i < tp->nr_args; i++) {
arg = tp->args + i;
if (unlikely(arg->dynamic)) {
len = process_fetch_insn(arg->code, regs, NULL, NULL);
if (len > 0)
ret += len;
}
}
return ret;
}
/* Store the value of each argument */
static nokprobe_inline void
store_trace_args(void *data, struct trace_probe *tp, void *rec,
int header_size, int maxlen)
{
struct probe_arg *arg;
void *base = data - header_size;
void *dyndata = data + tp->size;
u32 *dl; /* Data location */
int ret, i;
for (i = 0; i < tp->nr_args; i++) {
arg = tp->args + i;
dl = data + arg->offset;
/* Point the dynamic data area if needed */
if (unlikely(arg->dynamic))
*dl = make_data_loc(maxlen, dyndata - base);
ret = process_fetch_insn(arg->code, rec, dl, base);
if (unlikely(ret < 0 && arg->dynamic)) {
*dl = make_data_loc(0, dyndata - base);
} else {
dyndata += ret;
maxlen -= ret;
}
}
}
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