From 7ee3e97e00a3893e354c3993c3f7d9dc127e9c5e Mon Sep 17 00:00:00 2001 From: Christophe Leroy Date: Thu, 13 May 2021 09:07:51 +0000 Subject: [PATCH] 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 Signed-off-by: Christophe Leroy Reviewed-by: Naveen N. Rao Acked-by: Masami Hiramatsu Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/40a43d6df1fdf41ade36e9a46e60a4df774ca9f6.1620896780.git.christophe.leroy@csgroup.eu --- include/linux/kprobes.h | 3 +++ kernel/kprobes.c | 14 ++++++++++++-- 2 files changed, 15 insertions(+), 2 deletions(-) diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h index 1883a4a..02d4020 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 745f08f..8c0a6fd 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 */ -- 2.7.4