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Commit 49e0b465 authored by Naveen N. Rao's avatar Naveen N. Rao Committed by Michael Ellerman
Browse files

kprobes: Convert kprobe_lookup_name() to a function 



The macro is now pretty long and ugly on powerpc. In the light of further
changes needed here, convert it to a __weak variant to be over-ridden with a
nicer looking function.

Suggested-by: default avatarMasami Hiramatsu <mhiramat@kernel.org>
Acked-by: default avatarMasami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: default avatarNaveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent a460246c

arch/powerpc/include/asm/kprobes.h

+0 −53
Original line number Diff line number Diff line
@@ -61,59 +61,6 @@ extern kprobe_opcode_t optprobe_template_end[]; 
#define MAX_OPTINSN_SIZE	(optprobe_template_end - optprobe_template_entry)

#define RELATIVEJUMP_SIZE	sizeof(kprobe_opcode_t)	/* 4 bytes */



#ifdef PPC64_ELF_ABI_v2

/* PPC64 ABIv2 needs local entry point */

#define kprobe_lookup_name(name, addr)					\

{									\

	addr = (kprobe_opcode_t *)kallsyms_lookup_name(name);		\

	if (addr)							\

		addr = (kprobe_opcode_t *)ppc_function_entry(addr);	\

}

#elif defined(PPC64_ELF_ABI_v1)

/*

 * 64bit powerpc ABIv1 uses function descriptors:

 * - Check for the dot variant of the symbol first.

 * - If that fails, try looking up the symbol provided.

 *

 * This ensures we always get to the actual symbol and not the descriptor.

 * Also handle <module:symbol> format.

 */

#define kprobe_lookup_name(name, addr)					\

{									\

	char dot_name[MODULE_NAME_LEN + 1 + KSYM_NAME_LEN];		\

	const char *modsym;							\

	bool dot_appended = false;					\

	if ((modsym = strchr(name, ':')) != NULL) {			\

		modsym++;						\

		if (*modsym != '\0' && *modsym != '.') {		\

			/* Convert to <module:.symbol> */		\

			strncpy(dot_name, name, modsym - name);		\

			dot_name[modsym - name] = '.';			\

			dot_name[modsym - name + 1] = '\0';		\

			strncat(dot_name, modsym,			\

				sizeof(dot_name) - (modsym - name) - 2);\

			dot_appended = true;				\

		} else {						\

			dot_name[0] = '\0';				\

			strncat(dot_name, name, sizeof(dot_name) - 1);	\

		}							\

	} else if (name[0] != '.') {					\

		dot_name[0] = '.';					\

		dot_name[1] = '\0';					\

		strncat(dot_name, name, KSYM_NAME_LEN - 2);		\

		dot_appended = true;					\

	} else {							\

		dot_name[0] = '\0';					\

		strncat(dot_name, name, KSYM_NAME_LEN - 1);		\

	}								\

	addr = (kprobe_opcode_t *)kallsyms_lookup_name(dot_name);	\

	if (!addr && dot_appended) {					\

		/* Let's try the original non-dot symbol lookup	*/	\

		addr = (kprobe_opcode_t *)kallsyms_lookup_name(name);	\

	}								\

}

#endif



#define flush_insn_slot(p)	do { } while (0)

#define kretprobe_blacklist_size 0

arch/powerpc/kernel/kprobes.c

+58 −0
Original line number Diff line number Diff line
@@ -42,6 +42,64 @@ DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk); 


struct kretprobe_blackpoint kretprobe_blacklist[] = {{NULL, NULL}};



kprobe_opcode_t *kprobe_lookup_name(const char *name)

{

	kprobe_opcode_t *addr;



#ifdef PPC64_ELF_ABI_v2

	/* PPC64 ABIv2 needs local entry point */

	addr = (kprobe_opcode_t *)kallsyms_lookup_name(name);

	if (addr)

		addr = (kprobe_opcode_t *)ppc_function_entry(addr);

#elif defined(PPC64_ELF_ABI_v1)

	/*

	 * 64bit powerpc ABIv1 uses function descriptors:

	 * - Check for the dot variant of the symbol first.

	 * - If that fails, try looking up the symbol provided.

	 *

	 * This ensures we always get to the actual symbol and not

	 * the descriptor.

	 *

	 * Also handle <module:symbol> format.

	 */

	char dot_name[MODULE_NAME_LEN + 1 + KSYM_NAME_LEN];

	const char *modsym;

	bool dot_appended = false;

	if ((modsym = strchr(name, ':')) != NULL) {

		modsym++;

		if (*modsym != '\0' && *modsym != '.') {

			/* Convert to <module:.symbol> */

			strncpy(dot_name, name, modsym - name);

			dot_name[modsym - name] = '.';

			dot_name[modsym - name + 1] = '\0';

			strncat(dot_name, modsym,

				sizeof(dot_name) - (modsym - name) - 2);

			dot_appended = true;

		} else {

			dot_name[0] = '\0';

			strncat(dot_name, name, sizeof(dot_name) - 1);

		}

	} else if (name[0] != '.') {

		dot_name[0] = '.';

		dot_name[1] = '\0';

		strncat(dot_name, name, KSYM_NAME_LEN - 2);

		dot_appended = true;

	} else {

		dot_name[0] = '\0';

		strncat(dot_name, name, KSYM_NAME_LEN - 1);

	}

	addr = (kprobe_opcode_t *)kallsyms_lookup_name(dot_name);

	if (!addr && dot_appended) {

		/* Let's try the original non-dot symbol lookup	*/

		addr = (kprobe_opcode_t *)kallsyms_lookup_name(name);

	}

#else

	addr = (kprobe_opcode_t *)kallsyms_lookup_name(name);

#endif



	return addr;

}



int __kprobes arch_prepare_kprobe(struct kprobe *p)

{

	int ret = 0;

arch/powerpc/kernel/optprobes.c

+2 −2
Original line number Diff line number Diff line
@@ -243,8 +243,8 @@ int arch_prepare_optimized_kprobe(struct optimized_kprobe *op, struct kprobe *p) 
	/*

	 * 2. branch to optimized_callback() and emulate_step()

	 */

	kprobe_lookup_name("optimized_callback", op_callback_addr);

	kprobe_lookup_name("emulate_step", emulate_step_addr);

	op_callback_addr = kprobe_lookup_name("optimized_callback");

	emulate_step_addr = kprobe_lookup_name("emulate_step");

	if (!op_callback_addr || !emulate_step_addr) {

		WARN(1, "kprobe_lookup_name() failed\n");

		goto error;

include/linux/kprobes.h

+1 −0
Original line number Diff line number Diff line
@@ -379,6 +379,7 @@ static inline struct kprobe_ctlblk *get_kprobe_ctlblk(void) 
	return this_cpu_ptr(&kprobe_ctlblk);

}



kprobe_opcode_t *kprobe_lookup_name(const char *name);

int register_kprobe(struct kprobe *p);

void unregister_kprobe(struct kprobe *p);

int register_kprobes(struct kprobe **kps, int num);

kernel/kprobes.c

+8 −12
Original line number Diff line number Diff line
@@ -58,15 +58,6 @@ 
#define KPROBE_TABLE_SIZE (1 << KPROBE_HASH_BITS)





/*

 * Some oddball architectures like 64bit powerpc have function descriptors

 * so this must be overridable.

 */

#ifndef kprobe_lookup_name

#define kprobe_lookup_name(name, addr) \

	addr = ((kprobe_opcode_t *)(kallsyms_lookup_name(name)))

#endif



static int kprobes_initialized;

static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE];

static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE];
@@ -81,6 +72,11 @@ static struct { 
	raw_spinlock_t lock ____cacheline_aligned_in_smp;

} kretprobe_table_locks[KPROBE_TABLE_SIZE];



kprobe_opcode_t * __weak kprobe_lookup_name(const char *name)

{

	return ((kprobe_opcode_t *)(kallsyms_lookup_name(name)));

}



static raw_spinlock_t *kretprobe_table_lock_ptr(unsigned long hash)

{

	return &(kretprobe_table_locks[hash].lock);
@@ -1407,7 +1403,7 @@ static kprobe_opcode_t *kprobe_addr(struct kprobe *p) 
		goto invalid;



	if (p->symbol_name) {

		kprobe_lookup_name(p->symbol_name, addr);

		addr = kprobe_lookup_name(p->symbol_name);

		if (!addr)

			return ERR_PTR(-ENOENT);

	}
@@ -2199,8 +2195,8 @@ static int __init init_kprobes(void) 
	if (kretprobe_blacklist_size) {

		/* lookup the function address from its name */

		for (i = 0; kretprobe_blacklist[i].name != NULL; i++) {

			kprobe_lookup_name(kretprobe_blacklist[i].name,

					   kretprobe_blacklist[i].addr);

			kretprobe_blacklist[i].addr =

				kprobe_lookup_name(kretprobe_blacklist[i].name);

			if (!kretprobe_blacklist[i].addr)

				printk("kretprobe: lookup failed: %s\n",

				       kretprobe_blacklist[i].name);