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