Messages in this thread Patch in this message | | | From | Srikar Dronamraju <> | Date | Mon, 14 Mar 2011 19:06:54 +0530 | Subject | [PATCH v2 2.6.38-rc8-tip 15/20] 15: x86: uprobes exception notifier for x86. |
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Provides a uprobes exception notifier for x86. This uprobes_exception notifier gets called in interrupt context and routes int3 and singlestep exception when a uprobed process encounters a INT3 or a singlestep exception.
Signed-off-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> --- arch/x86/include/asm/uprobes.h | 3 +++ arch/x86/kernel/signal.c | 14 ++++++++++++++ arch/x86/kernel/uprobes.c | 29 +++++++++++++++++++++++++++++ 3 files changed, 46 insertions(+), 0 deletions(-)
diff --git a/arch/x86/include/asm/uprobes.h b/arch/x86/include/asm/uprobes.h index 0e1b23f..f49cf49 100644 --- a/arch/x86/include/asm/uprobes.h +++ b/arch/x86/include/asm/uprobes.h @@ -22,6 +22,7 @@ * Srikar Dronamraju * Jim Keniston */ +#include <linux/notifier.h> typedef u8 uprobe_opcode_t; #define MAX_UINSN_BYTES 16 @@ -52,4 +53,6 @@ extern int pre_xol(struct uprobe *uprobe, struct pt_regs *regs); extern int post_xol(struct uprobe *uprobe, struct pt_regs *regs); extern void arch_uprobe_enable_sstep(struct pt_regs *regs); extern void arch_uprobe_disable_sstep(struct pt_regs *regs); +extern int uprobes_exception_notify(struct notifier_block *self, + unsigned long val, void *data); #endif /* _ASM_UPROBES_H */ diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c index 4fd173c..0b06b94 100644 --- a/arch/x86/kernel/signal.c +++ b/arch/x86/kernel/signal.c @@ -20,6 +20,7 @@ #include <linux/personality.h> #include <linux/uaccess.h> #include <linux/user-return-notifier.h> +#include <linux/uprobes.h> #include <asm/processor.h> #include <asm/ucontext.h> @@ -848,6 +849,19 @@ do_notify_resume(struct pt_regs *regs, void *unused, __u32 thread_info_flags) if (thread_info_flags & _TIF_SIGPENDING) do_signal(regs); + if (thread_info_flags & _TIF_UPROBE) { + clear_thread_flag(TIF_UPROBE); +#ifdef CONFIG_X86_32 + /* + * On x86_32, do_notify_resume() gets called with + * interrupts disabled. Hence enable interrupts if they + * are still disabled. + */ + local_irq_enable(); +#endif + uprobe_notify_resume(regs); + } + if (thread_info_flags & _TIF_NOTIFY_RESUME) { clear_thread_flag(TIF_NOTIFY_RESUME); tracehook_notify_resume(regs); diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c index 5667e90..b55469c 100644 --- a/arch/x86/kernel/uprobes.c +++ b/arch/x86/kernel/uprobes.c @@ -569,3 +569,32 @@ void arch_uprobe_disable_sstep(struct pt_regs *regs) clear_thread_flag(TIF_FORCED_TF); regs->flags &= ~X86_EFLAGS_TF; } + +/* + * Wrapper routine for handling exceptions. + */ +int uprobes_exception_notify(struct notifier_block *self, + unsigned long val, void *data) +{ + struct die_args *args = data; + struct pt_regs *regs = args->regs; + int ret = NOTIFY_DONE; + + /* We are only interested in userspace traps */ + if (regs && !user_mode_vm(regs)) + return NOTIFY_DONE; + + switch (val) { + case DIE_INT3: + /* Run your handler here */ + if (uprobe_bkpt_notifier(regs)) + ret = NOTIFY_STOP; + break; + case DIE_DEBUG: + if (uprobe_post_notifier(regs)) + ret = NOTIFY_STOP; + default: + break; + } + return ret; +}
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