From 593befa6ab74a805e4f503c8c737c3cffa8066b6 Mon Sep 17 00:00:00 2001 From: Dominik Dingel Date: Thu, 23 Oct 2014 12:07:44 +0200 Subject: mm: introduce mm_forbids_zeropage function Add a new function stub to allow architectures to disable for an mm_structthe backing of non-present, anonymous pages with read-only empty zero pages. Signed-off-by: Dominik Dingel Reviewed-by: Paolo Bonzini Signed-off-by: Martin Schwidefsky --- include/linux/mm.h | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'include/linux') diff --git a/include/linux/mm.h b/include/linux/mm.h index 27eb1bfbe704..ab7dadca4ea5 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -56,6 +56,17 @@ extern int sysctl_legacy_va_layout; #define __pa_symbol(x) __pa(RELOC_HIDE((unsigned long)(x), 0)) #endif +/* + * To prevent common memory management code establishing + * a zero page mapping on a read fault. + * This macro should be defined within . + * s390 does this to prevent multiplexing of hardware bits + * related to the physical page in case of virtualization. + */ +#ifndef mm_forbids_zeropage +#define mm_forbids_zeropage(X) (0) +#endif + extern unsigned long sysctl_user_reserve_kbytes; extern unsigned long sysctl_admin_reserve_kbytes; -- cgit v1.2.3 From f7f242ff004499e0904d3664713dfba01f24c408 Mon Sep 17 00:00:00 2001 From: Heiko Carstens Date: Wed, 15 Oct 2014 12:17:34 +0200 Subject: kprobes: introduce weak arch_check_ftrace_location() helper function Introduce weak arch_check_ftrace_location() helper function which architectures can override in order to implement handling of kprobes on function tracer call sites on their own, without depending on common code or implementing the KPROBES_ON_FTRACE feature. Signed-off-by: Heiko Carstens Acked-by: Masami Hiramatsu Acked-by: Steven Rostedt Signed-off-by: Martin Schwidefsky --- include/linux/kprobes.h | 1 + kernel/kprobes.c | 18 +++++++++++------- 2 files changed, 12 insertions(+), 7 deletions(-) (limited to 'include/linux') diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h index f7296e57d614..5297f9fa0ef2 100644 --- a/include/linux/kprobes.h +++ b/include/linux/kprobes.h @@ -335,6 +335,7 @@ extern void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip, extern int arch_prepare_kprobe_ftrace(struct kprobe *p); #endif +int arch_check_ftrace_location(struct kprobe *p); /* Get the kprobe at this addr (if any) - called with preemption disabled */ struct kprobe *get_kprobe(void *addr); diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 3995f546d0f3..317eb8ad28dd 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -1410,16 +1410,10 @@ static inline int check_kprobe_rereg(struct kprobe *p) return ret; } -static int check_kprobe_address_safe(struct kprobe *p, - struct module **probed_mod) +int __weak arch_check_ftrace_location(struct kprobe *p) { - int ret = 0; unsigned long ftrace_addr; - /* - * If the address is located on a ftrace nop, set the - * breakpoint to the following instruction. - */ ftrace_addr = ftrace_location((unsigned long)p->addr); if (ftrace_addr) { #ifdef CONFIG_KPROBES_ON_FTRACE @@ -1431,7 +1425,17 @@ static int check_kprobe_address_safe(struct kprobe *p, return -EINVAL; #endif } + return 0; +} +static int check_kprobe_address_safe(struct kprobe *p, + struct module **probed_mod) +{ + int ret; + + ret = arch_check_ftrace_location(p); + if (ret) + return ret; jump_label_lock(); preempt_disable(); -- cgit v1.2.3