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Commit 9b960a38 authored by Masami Hiramatsu's avatar Masami Hiramatsu Committed by Steven Rostedt (VMware)
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tracing: probeevent: Unify fetch_insn processing common part 

Unify the fetch_insn bottom process (from stage 2: dereference
indirect data) from kprobe and uprobe events, since those are
mostly same.

Link: http://lkml.kernel.org/r/152465879965.26224.8547240824606804815.stgit@devbox



Signed-off-by: default avatarMasami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: default avatarSteven Rostedt (VMware) <rostedt@goodmis.org>
parent 0a46c854

kernel/trace/trace_kprobe.c

+7 −40
Original line number Diff line number Diff line
@@ -899,13 +899,18 @@ fetch_store_string(unsigned long addr, void *dest, void *base) 
	return ret;

}



static nokprobe_inline int

probe_mem_read(void *dest, void *src, size_t size)

{

	return probe_kernel_read(dest, src, size);

}



/* Note that we don't verify it, since the code does not come from user space */

static int

process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, void *dest,

		   void *base)

{

	unsigned long val;

	int ret = 0;



	/* 1st stage: get value from context */

	switch (code->op) {
@@ -932,45 +937,7 @@ process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, void *dest, 
	}

	code++;



	/* 2nd stage: dereference memory if needed */

	while (code->op == FETCH_OP_DEREF) {

		ret = probe_kernel_read(&val, (void *)val + code->offset,

					sizeof(val));

		if (ret)

			return ret;

		code++;

	}



	/* 3rd stage: store value to buffer */

	if (unlikely(!dest)) {

		if (code->op == FETCH_OP_ST_STRING)

			return fetch_store_strlen(val + code->offset);

		else

			return -EILSEQ;

	}



	switch (code->op) {

	case FETCH_OP_ST_RAW:

		fetch_store_raw(val, code, dest);

		break;

	case FETCH_OP_ST_MEM:

		probe_kernel_read(dest, (void *)val + code->offset, code->size);

		break;

	case FETCH_OP_ST_STRING:

		ret = fetch_store_string(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++;

	}



	return code->op == FETCH_OP_END ? ret : -EILSEQ;

	return process_fetch_insn_bottom(code, val, dest, base);

}

NOKPROBE_SYMBOL(process_fetch_insn)

kernel/trace/trace_probe_tmpl.h

+54 −1
Original line number Diff line number Diff line
@@ -49,13 +49,66 @@ fetch_apply_bitfield(struct fetch_insn *code, void *buf) 
}



/*

 * This must be defined for each callsite.

 * 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, struct pt_regs *regs,

		   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

probe_mem_read(void *dest, void *src, size_t size);



/* 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)

{

	int ret = 0;



	/* 2nd stage: dereference memory if needed */

	while (code->op == FETCH_OP_DEREF) {

		ret = probe_mem_read(&val, (void *)val + code->offset,

					sizeof(val));

		if (ret)

			return ret;

		code++;

	}



	/* 3rd stage: store value to buffer */

	if (unlikely(!dest)) {

		if (code->op == FETCH_OP_ST_STRING)

			return fetch_store_strlen(val + code->offset);

		else

			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_STRING:

		ret = fetch_store_string(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++;

	}



	return code->op == FETCH_OP_END ? ret : -EILSEQ;

}



/* Sum up total data length for dynamic arraies (strings) */

static nokprobe_inline int

kernel/trace/trace_uprobe.c

+2 −41
Original line number Diff line number Diff line
@@ -101,7 +101,7 @@ static unsigned long get_user_stack_nth(struct pt_regs *regs, unsigned int n) 
 * Uprobes-specific fetch functions

 */

static nokprobe_inline int

probe_user_read(void *dest, void *src, size_t size)

probe_mem_read(void *dest, void *src, size_t size)

{

	void __user *vaddr = (void __force __user *)src;
@@ -162,7 +162,6 @@ process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, void *dest, 
		   void *base)

{

	unsigned long val;

	int ret = 0;



	/* 1st stage: get value from context */

	switch (code->op) {
@@ -189,45 +188,7 @@ process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, void *dest, 
	}

	code++;



	/* 2nd stage: dereference memory if needed */

	while (code->op == FETCH_OP_DEREF) {

		ret = probe_user_read(&val, (void *)val + code->offset,

				      sizeof(val));

		if (ret)

			return ret;

		code++;

	}



	/* 3rd stage: store value to buffer */

	if (unlikely(!dest)) {

		if (code->op == FETCH_OP_ST_STRING)

			return fetch_store_strlen(val + code->offset);

		else

			return -EILSEQ;

	}



	switch (code->op) {

	case FETCH_OP_ST_RAW:

		fetch_store_raw(val, code, dest);

		break;

	case FETCH_OP_ST_MEM:

		probe_kernel_read(dest, (void *)val + code->offset, code->size);

		break;

	case FETCH_OP_ST_STRING:

		ret = fetch_store_string(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++;

	}



	return code->op == FETCH_OP_END ? ret : -EILSEQ;

	return process_fetch_insn_bottom(code, val, dest, base);

}

NOKPROBE_SYMBOL(process_fetch_insn)