Message ID | dcf77485d32f1a49d0c79a5be7e038491c10ea2a.1491991939.git.naveen.n.rao@linux.vnet.ibm.com (mailing list archive) |
---|---|
State | Changes Requested |
Headers | show |
On Wed, 12 Apr 2017 16:28:25 +0530 "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com> wrote: > 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 GEP (Global entry point) if an > offset is specified and otherwise chooses the LEP (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 <ananth@linux.vnet.ibm.com> > Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> > --- > arch/powerpc/kernel/kprobes.c | 4 ++-- > arch/powerpc/kernel/optprobes.c | 4 ++-- > include/linux/kprobes.h | 2 +- > kernel/kprobes.c | 7 ++++--- > 4 files changed, 9 insertions(+), 8 deletions(-) > > diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c > index a7aa7394954d..0732a0291ace 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) Hmm, if we do this change, it is natural that kprobe_lookup_name() returns the address + offset. Thank you,
diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c index a7aa7394954d..0732a0291ace 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 f3421b6b47a3..6a128f3a7ed1 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))); } @@ -1396,7 +1397,7 @@ 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); } @@ -2189,7 +2190,7 @@ 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);