From 474c256841074b913e76e392082373e12103a75d Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Tue, 26 Sep 2006 10:52:35 +0200 Subject: [PATCH] i386: make fault notifier unconditional and export it It's needed for external debuggers and overhead is very small. Also make the actual notifier chain they use static Cc: jbeulich@novell.com Signed-off-by: Andi Kleen --- arch/i386/mm/fault.c | 14 ++++---------- 1 file changed, 4 insertions(+), 10 deletions(-) (limited to 'arch/i386/mm/fault.c') diff --git a/arch/i386/mm/fault.c b/arch/i386/mm/fault.c index f7279468323..0ce86168a0b 100644 --- a/arch/i386/mm/fault.c +++ b/arch/i386/mm/fault.c @@ -30,18 +30,20 @@ extern void die(const char *,struct pt_regs *,long); -#ifdef CONFIG_KPROBES -ATOMIC_NOTIFIER_HEAD(notify_page_fault_chain); +static ATOMIC_NOTIFIER_HEAD(notify_page_fault_chain); + int register_page_fault_notifier(struct notifier_block *nb) { vmalloc_sync_all(); return atomic_notifier_chain_register(¬ify_page_fault_chain, nb); } +EXPORT_SYMBOL_GPL(register_page_fault_notifier); int unregister_page_fault_notifier(struct notifier_block *nb) { return atomic_notifier_chain_unregister(¬ify_page_fault_chain, nb); } +EXPORT_SYMBOL_GPL(unregister_page_fault_notifier); static inline int notify_page_fault(enum die_val val, const char *str, struct pt_regs *regs, long err, int trap, int sig) @@ -55,14 +57,6 @@ static inline int notify_page_fault(enum die_val val, const char *str, }; return atomic_notifier_call_chain(¬ify_page_fault_chain, val, &args); } -#else -static inline int notify_page_fault(enum die_val val, const char *str, - struct pt_regs *regs, long err, int trap, int sig) -{ - return NOTIFY_DONE; -} -#endif - /* * Unlock any spinlocks which will prevent us from getting the -- cgit From 78be3706b21a232310590fe00258b224177ac05f Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Tue, 26 Sep 2006 10:52:39 +0200 Subject: [PATCH] i386: Allow a kernel not to be in ring 0 We allow for the fact that the guest kernel may not run in ring 0. This requires some abstraction in a few places when setting %cs or checking privilege level (user vs kernel). This is Chris' [RFC PATCH 15/33] move segment checks to subarch, except rather than using #define USER_MODE_MASK which depends on a config option, we use Zach's more flexible approach of assuming ring 3 == userspace. I also used "get_kernel_rpl()" over "get_kernel_cs()" because I think it reads better in the code... 1) Remove the hardcoded 3 and introduce #define SEGMENT_RPL_MASK 3 2) Add a get_kernel_rpl() macro, and don't assume it's zero. And: Clean up of patch for letting kernel run other than ring 0: a. Add some comments about the SEGMENT_IS_*_CODE() macros. b. Add a USER_RPL macro. (Code was comparing a value to a mask in some places and to the magic number 3 in other places.) c. Add macros for table indicator field and use them. d. Change the entry.S tests for LDT stack segment to use the macros Signed-off-by: Rusty Russell Signed-off-by: Zachary Amsden Signed-off-by: Jeremy Fitzhardinge Signed-off-by: Andrew Morton Signed-off-by: Andi Kleen --- arch/i386/mm/fault.c | 11 ++++------- 1 file changed, 4 insertions(+), 7 deletions(-) (limited to 'arch/i386/mm/fault.c') diff --git a/arch/i386/mm/fault.c b/arch/i386/mm/fault.c index 0ce86168a0b..5e17a3f43b4 100644 --- a/arch/i386/mm/fault.c +++ b/arch/i386/mm/fault.c @@ -27,6 +27,7 @@ #include #include #include +#include extern void die(const char *,struct pt_regs *,long); @@ -113,10 +114,10 @@ static inline unsigned long get_segment_eip(struct pt_regs *regs, } /* The standard kernel/user address space limit. */ - *eip_limit = (seg & 3) ? USER_DS.seg : KERNEL_DS.seg; + *eip_limit = user_mode(regs) ? USER_DS.seg : KERNEL_DS.seg; /* By far the most common cases. */ - if (likely(seg == __USER_CS || seg == __KERNEL_CS)) + if (likely(SEGMENT_IS_FLAT_CODE(seg))) return eip; /* Check the segment exists, is within the current LDT/GDT size, @@ -430,11 +431,7 @@ good_area: write = 0; switch (error_code & 3) { default: /* 3: write, present */ -#ifdef TEST_VERIFY_AREA - if (regs->cs == KERNEL_CS) - printk("WP fault at %08lx\n", regs->eip); -#endif - /* fall through */ + /* fall through */ case 2: /* write, not present */ if (!(vma->vm_flags & VM_WRITE)) goto bad_area; -- cgit