From: Naveen N. Rao Date: Wed, 19 Apr 2017 12:51:01 +0000 (+0530) Subject: powerpc/kprobes: Fix handling of function offsets on ABIv2 X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=290e3070762ac80e5fc4087d8c4de7e3f1d90aca;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git powerpc/kprobes: Fix handling of function offsets on ABIv2 commit 239aeba76409 ("perf powerpc: Fix kprobe and kretprobe handling with kallsyms on ppc64le") changed how we use the offset field in struct kprobe on ABIv2. perf now offsets from the global entry point if an offset is specified and otherwise chooses the local entry point. Fix the same in kernel for kprobe API users. We do this by extending kprobe_lookup_name() to accept an additional parameter to indicate the offset specified with the kprobe registration. If offset is 0, we return the local function entry and return the global entry point otherwise. With: # cd /sys/kernel/debug/tracing/ # echo "p _do_fork" >> kprobe_events # echo "p _do_fork+0x10" >> kprobe_events before this patch: # cat ../kprobes/list c0000000000d0748 k _do_fork+0x8 [DISABLED] c0000000000d0758 k _do_fork+0x18 [DISABLED] c0000000000412b0 k kretprobe_trampoline+0x0 [OPTIMIZED] and after: # cat ../kprobes/list c0000000000d04c8 k _do_fork+0x8 [DISABLED] c0000000000d04d0 k _do_fork+0x10 [DISABLED] c0000000000412b0 k kretprobe_trampoline+0x0 [OPTIMIZED] Acked-by: Ananth N Mavinakayanahalli Signed-off-by: Naveen N. Rao Signed-off-by: Michael Ellerman --- diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c index e5f518a962c6..65828fbc410d 100644 --- a/arch/powerpc/kernel/kprobes.c +++ b/arch/powerpc/kernel/kprobes.c @@ -42,14 +42,14 @@ 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 *kprobe_lookup_name(const char *name, unsigned int offset) { 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) + if (addr && !offset) addr = (kprobe_opcode_t *)ppc_function_entry(addr); #elif defined(PPC64_ELF_ABI_v1) /* diff --git a/arch/powerpc/kernel/optprobes.c b/arch/powerpc/kernel/optprobes.c index aefe076d00e0..ce81a322251c 100644 --- a/arch/powerpc/kernel/optprobes.c +++ b/arch/powerpc/kernel/optprobes.c @@ -243,8 +243,8 @@ int arch_prepare_optimized_kprobe(struct optimized_kprobe *op, struct kprobe *p) /* * 2. branch to optimized_callback() and emulate_step() */ - op_callback_addr = kprobe_lookup_name("optimized_callback"); - emulate_step_addr = kprobe_lookup_name("emulate_step"); + op_callback_addr = kprobe_lookup_name("optimized_callback", 0); + emulate_step_addr = kprobe_lookup_name("emulate_step", 0); if (!op_callback_addr || !emulate_step_addr) { WARN(1, "kprobe_lookup_name() failed\n"); goto error; diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h index 16f153c84646..1f82a3db00b1 100644 --- a/include/linux/kprobes.h +++ b/include/linux/kprobes.h @@ -379,7 +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); +kprobe_opcode_t *kprobe_lookup_name(const char *name, unsigned int offset); int register_kprobe(struct kprobe *p); void unregister_kprobe(struct kprobe *p); int register_kprobes(struct kprobe **kps, int num); diff --git a/kernel/kprobes.c b/kernel/kprobes.c index e5087e692b42..406889889ce5 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -72,7 +72,8 @@ 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) +kprobe_opcode_t * __weak kprobe_lookup_name(const char *name, + unsigned int __unused) { return ((kprobe_opcode_t *)(kallsyms_lookup_name(name))); } @@ -1403,7 +1404,7 @@ static kprobe_opcode_t *kprobe_addr(struct kprobe *p) goto invalid; if (p->symbol_name) { - addr = kprobe_lookup_name(p->symbol_name); + addr = kprobe_lookup_name(p->symbol_name, p->offset); if (!addr) return ERR_PTR(-ENOENT); } @@ -2196,7 +2197,7 @@ static int __init init_kprobes(void) /* lookup the function address from its name */ for (i = 0; kretprobe_blacklist[i].name != NULL; i++) { kretprobe_blacklist[i].addr = - kprobe_lookup_name(kretprobe_blacklist[i].name); + kprobe_lookup_name(kretprobe_blacklist[i].name, 0); if (!kretprobe_blacklist[i].addr) printk("kretprobe: lookup failed: %s\n", kretprobe_blacklist[i].name);