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author | Ingo Molnar <mingo@elte.hu> | 2008-07-10 11:43:00 +0200 |
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committer | Ingo Molnar <mingo@elte.hu> | 2008-07-10 11:43:00 +0200 |
commit | bac0c9103b31c3dd83ad9d731dd9834e2ba75e4f (patch) | |
tree | 702dd6a7ce06d224d594c2293af546b11ac9f51b /arch/x86/mm | |
parent | Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rol... (diff) | |
parent | ftrace: prevent ftrace modifications while being kprobe'd, v2 (diff) | |
download | linux-bac0c9103b31c3dd83ad9d731dd9834e2ba75e4f.tar.xz linux-bac0c9103b31c3dd83ad9d731dd9834e2ba75e4f.zip |
Merge branch 'tracing/ftrace' into auto-ftrace-next
Diffstat (limited to 'arch/x86/mm')
-rw-r--r-- | arch/x86/mm/fault.c | 56 | ||||
-rw-r--r-- | arch/x86/mm/init_32.c | 4 | ||||
-rw-r--r-- | arch/x86/mm/init_64.c | 10 |
3 files changed, 68 insertions, 2 deletions
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index 8bcb6f40ccb6..42394b353c6a 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -49,6 +49,60 @@ #define PF_RSVD (1<<3) #define PF_INSTR (1<<4) +#ifdef CONFIG_PAGE_FAULT_HANDLERS +static HLIST_HEAD(pf_handlers); /* protected by RCU */ +static DEFINE_SPINLOCK(pf_handlers_writer); + +void register_page_fault_handler(struct pf_handler *new_pfh) +{ + unsigned long flags; + spin_lock_irqsave(&pf_handlers_writer, flags); + hlist_add_head_rcu(&new_pfh->hlist, &pf_handlers); + spin_unlock_irqrestore(&pf_handlers_writer, flags); +} +EXPORT_SYMBOL_GPL(register_page_fault_handler); + +/** + * unregister_page_fault_handler: + * The caller must ensure @old_pfh is not in use anymore before freeing it. + * This function does not guarantee it. The list of handlers is protected by + * RCU, so you can do this by e.g. calling synchronize_rcu(). + */ +void unregister_page_fault_handler(struct pf_handler *old_pfh) +{ + unsigned long flags; + spin_lock_irqsave(&pf_handlers_writer, flags); + hlist_del_rcu(&old_pfh->hlist); + spin_unlock_irqrestore(&pf_handlers_writer, flags); +} +EXPORT_SYMBOL_GPL(unregister_page_fault_handler); +#endif + +/* returns non-zero if do_page_fault() should return */ +static int handle_custom_pf(struct pt_regs *regs, unsigned long error_code, + unsigned long address) +{ +#ifdef CONFIG_PAGE_FAULT_HANDLERS + int ret = 0; + struct pf_handler *cur; + struct hlist_node *ncur; + + if (hlist_empty(&pf_handlers)) + return 0; + + rcu_read_lock(); + hlist_for_each_entry_rcu(cur, ncur, &pf_handlers, hlist) { + ret = cur->handler(regs, error_code, address); + if (ret) + break; + } + rcu_read_unlock(); + return ret; +#else + return 0; +#endif +} + static inline int notify_page_fault(struct pt_regs *regs) { #ifdef CONFIG_KPROBES @@ -606,6 +660,8 @@ void __kprobes do_page_fault(struct pt_regs *regs, unsigned long error_code) if (notify_page_fault(regs)) return; + if (handle_custom_pf(regs, error_code, address)) + return; /* * We fault-in kernel-space virtual memory on-demand. The diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c index ec30d10154b6..f96eca21ad8f 100644 --- a/arch/x86/mm/init_32.c +++ b/arch/x86/mm/init_32.c @@ -710,6 +710,8 @@ void mark_rodata_ro(void) unsigned long start = PFN_ALIGN(_text); unsigned long size = PFN_ALIGN(_etext) - start; +#ifndef CONFIG_DYNAMIC_FTRACE + /* Dynamic tracing modifies the kernel text section */ set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT); printk(KERN_INFO "Write protecting the kernel text: %luk\n", size >> 10); @@ -722,6 +724,8 @@ void mark_rodata_ro(void) printk(KERN_INFO "Testing CPA: write protecting again\n"); set_pages_ro(virt_to_page(start), size>>PAGE_SHIFT); #endif +#endif /* CONFIG_DYNAMIC_FTRACE */ + start += size; size = (unsigned long)__end_rodata - start; set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT); diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c index 819dad973b13..17c0a6138a53 100644 --- a/arch/x86/mm/init_64.c +++ b/arch/x86/mm/init_64.c @@ -767,6 +767,13 @@ EXPORT_SYMBOL_GPL(rodata_test_data); void mark_rodata_ro(void) { unsigned long start = PFN_ALIGN(_stext), end = PFN_ALIGN(__end_rodata); + unsigned long rodata_start = + ((unsigned long)__start_rodata + PAGE_SIZE - 1) & PAGE_MASK; + +#ifdef CONFIG_DYNAMIC_FTRACE + /* Dynamic tracing modifies the kernel text section */ + start = rodata_start; +#endif printk(KERN_INFO "Write protecting the kernel read-only data: %luk\n", (end - start) >> 10); @@ -776,8 +783,7 @@ void mark_rodata_ro(void) * The rodata section (but not the kernel text!) should also be * not-executable. */ - start = ((unsigned long)__start_rodata + PAGE_SIZE - 1) & PAGE_MASK; - set_memory_nx(start, (end - start) >> PAGE_SHIFT); + set_memory_nx(rodata_start, (end - rodata_start) >> PAGE_SHIFT); rodata_test(); |