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authorChristophe Leroy <christophe.leroy@csgroup.eu>2021-05-13 09:07:51 +0000
committerMichael Ellerman <mpe@ellerman.id.au>2021-05-23 20:51:35 +1000
commit7ee3e97e00a3893e354c3993c3f7d9dc127e9c5e (patch)
tree9cd913eb3e356b43d2a0839837b4fd0a6472917b
parent6fcb574125e673f33ff058caa54b4e65629f3a08 (diff)
kprobes: Allow architectures to override optinsn page allocation
Some architectures like powerpc require a non standard allocation of optinsn page, because module pages are too far from the kernel for direct branches. Define weak alloc_optinsn_page() and free_optinsn_page(), that fall back on alloc_insn_page() and free_insn_page() when not overridden by the architecture. Suggested-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Reviewed-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/40a43d6df1fdf41ade36e9a46e60a4df774ca9f6.1620896780.git.christophe.leroy@csgroup.eu
-rw-r--r--include/linux/kprobes.h3
-rw-r--r--kernel/kprobes.c14
2 files changed, 15 insertions, 2 deletions
diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h
index 1883a4a9f16a..02d4020615a7 100644
--- a/include/linux/kprobes.h
+++ b/include/linux/kprobes.h
@@ -409,6 +409,9 @@ void dump_kprobe(struct kprobe *kp);
void *alloc_insn_page(void);
void free_insn_page(void *page);
+void *alloc_optinsn_page(void);
+void free_optinsn_page(void *page);
+
int kprobe_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
char *sym);
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 745f08fdd7a6..8c0a6fdef771 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -321,11 +321,21 @@ int kprobe_cache_get_kallsym(struct kprobe_insn_cache *c, unsigned int *symnum,
}
#ifdef CONFIG_OPTPROBES
+void __weak *alloc_optinsn_page(void)
+{
+ return alloc_insn_page();
+}
+
+void __weak free_optinsn_page(void *page)
+{
+ free_insn_page(page);
+}
+
/* For optimized_kprobe buffer */
struct kprobe_insn_cache kprobe_optinsn_slots = {
.mutex = __MUTEX_INITIALIZER(kprobe_optinsn_slots.mutex),
- .alloc = alloc_insn_page,
- .free = free_insn_page,
+ .alloc = alloc_optinsn_page,
+ .free = free_optinsn_page,
.sym = KPROBE_OPTINSN_PAGE_SYM,
.pages = LIST_HEAD_INIT(kprobe_optinsn_slots.pages),
/* .insn_size is initialized later */