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| author | Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> | 2017-04-19 18:21:01 +0530 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2017-04-20 23:18:55 +1000 |
| commit | 290e3070762ac80e5fc4087d8c4de7e3f1d90aca (patch) | |
| tree | c09a1a2111a7db3fa59b077aef7e18f931cdf73d /kernel/kprobes.c | |
| parent | 49e0b4658fe6aab5bf6bfe0738a86c1895930ad1 (diff) | |
| download | lwn-290e3070762ac80e5fc4087d8c4de7e3f1d90aca.tar.gz lwn-290e3070762ac80e5fc4087d8c4de7e3f1d90aca.zip | |
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 <ananth@linux.vnet.ibm.com>
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'kernel/kprobes.c')
| -rw-r--r-- | kernel/kprobes.c | 7 |
1 files changed, 4 insertions, 3 deletions
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); |