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authorNaveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>2017-09-22 12:10:45 +0300
committerMichael Ellerman <mpe@ellerman.id.au>2017-10-04 15:42:17 +0300
commitbf3a91251735863fcb230c96e984ebcacee820d9 (patch)
treea54610879baee8bc1b545f6e958e97aae080eec4 /arch
parenta7b440383f9b078254d38ab6a3672810f1eca74f (diff)
downloadlinux-bf3a91251735863fcb230c96e984ebcacee820d9.tar.xz
powerpc/kprobes: Clean up jprobe detection in livepatch handler
In commit c05b8c4474c03 ("powerpc/kprobes: Skip livepatch_handler() for jprobes"), we added a helper is_current_kprobe_addr() to help detect if the modified regs->nip was due to a jprobe or livepatch. Masami felt that the function name was not quite clear. To that end, this patch renames is_current_kprobe_addr() to __is_active_jprobe() and adds a comment to (hopefully) better clarify the purpose of this helper. The helper has also now been moved to kprobes-ftrace.c so that it is only available for KPROBES_ON_FTRACE. 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 'arch')
-rw-r--r--arch/powerpc/include/asm/kprobes.h2
-rw-r--r--arch/powerpc/kernel/kprobes-ftrace.c11
-rw-r--r--arch/powerpc/kernel/kprobes.c6
-rw-r--r--arch/powerpc/kernel/trace/ftrace_64_mprofile.S4
4 files changed, 14 insertions, 9 deletions
diff --git a/arch/powerpc/include/asm/kprobes.h b/arch/powerpc/include/asm/kprobes.h
index 8814a7249ceb..9f3be5c8a4a3 100644
--- a/arch/powerpc/include/asm/kprobes.h
+++ b/arch/powerpc/include/asm/kprobes.h
@@ -103,8 +103,8 @@ extern int kprobe_exceptions_notify(struct notifier_block *self,
extern int kprobe_fault_handler(struct pt_regs *regs, int trapnr);
extern int kprobe_handler(struct pt_regs *regs);
extern int kprobe_post_handler(struct pt_regs *regs);
-extern int is_current_kprobe_addr(unsigned long addr);
#ifdef CONFIG_KPROBES_ON_FTRACE
+extern int __is_active_jprobe(unsigned long addr);
extern int skip_singlestep(struct kprobe *p, struct pt_regs *regs,
struct kprobe_ctlblk *kcb);
#else
diff --git a/arch/powerpc/kernel/kprobes-ftrace.c b/arch/powerpc/kernel/kprobes-ftrace.c
index 6c089d9757c9..48f675a73cff 100644
--- a/arch/powerpc/kernel/kprobes-ftrace.c
+++ b/arch/powerpc/kernel/kprobes-ftrace.c
@@ -25,6 +25,17 @@
#include <linux/preempt.h>
#include <linux/ftrace.h>
+/*
+ * This is called from ftrace code after invoking registered handlers to
+ * disambiguate regs->nip changes done by jprobes and livepatch. We check if
+ * there is an active jprobe at the provided address (mcount location).
+ */
+int __is_active_jprobe(unsigned long addr)
+{
+ struct kprobe *p = kprobe_running();
+ return (p && (unsigned long)p->addr == addr) ? 1 : 0;
+}
+
static nokprobe_inline
int __skip_singlestep(struct kprobe *p, struct pt_regs *regs,
struct kprobe_ctlblk *kcb, unsigned long orig_nip)
diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c
index 4c1702423676..48a81614f629 100644
--- a/arch/powerpc/kernel/kprobes.c
+++ b/arch/powerpc/kernel/kprobes.c
@@ -43,12 +43,6 @@ DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
struct kretprobe_blackpoint kretprobe_blacklist[] = {{NULL, NULL}};
-int is_current_kprobe_addr(unsigned long addr)
-{
- struct kprobe *p = kprobe_running();
- return (p && (unsigned long)p->addr == addr) ? 1 : 0;
-}
-
bool arch_within_kprobe_blacklist(unsigned long addr)
{
return (addr >= (unsigned long)__kprobes_text_start &&
diff --git a/arch/powerpc/kernel/trace/ftrace_64_mprofile.S b/arch/powerpc/kernel/trace/ftrace_64_mprofile.S
index c98e90b4ea7b..c1cfcce0551d 100644
--- a/arch/powerpc/kernel/trace/ftrace_64_mprofile.S
+++ b/arch/powerpc/kernel/trace/ftrace_64_mprofile.S
@@ -110,9 +110,9 @@ ftrace_call:
/* NIP has not been altered, skip over further checks */
beq 1f
- /* Check if there is an active kprobe on us */
+ /* Check if there is an active jprobe on us */
subi r3, r14, 4
- bl is_current_kprobe_addr
+ bl __is_active_jprobe
nop
/*