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kprobes: Convert kprobe_lookup_name() to a function

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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: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Naveen N. Rao 2017-04-19 18:21:00 +05:30 committed by Michael Ellerman
parent a460246c70
commit 49e0b4658f
5 changed files with 69 additions and 67 deletions
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53
arch/powerpc/include/asm/kprobes.h
View file

@ -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

58
arch/powerpc/kernel/kprobes.c
View file

@ -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;

4
arch/powerpc/kernel/optprobes.c
View file

@ -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;

1
include/linux/kprobes.h
View file

@ -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);

20
kernel/kprobes.c
View file

@ -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);