[PATCH v4 3.0-rc2-tip 14/22] 14: x86: uprobes exception notifier for x86.
From: Srikar Dronamraju <hidden>
Date: 2011-06-07 13:07:56
Also in:
lkml
Subsystem:
the rest, uprobes, x86 architecture (32-bit and 64-bit) · Maintainers:
Linus Torvalds, Masami Hiramatsu, Oleg Nesterov, Peter Zijlstra, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
Provides a uprobes exception notifier for x86. This uprobe_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 <redacted> Signed-off-by: Srikar Dronamraju <redacted> --- 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 3a7833c..a5d9480 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
@@ -47,4 +48,6 @@ extern int analyze_insn(struct task_struct *tsk, struct uprobe *uprobe); extern void set_instruction_pointer(struct pt_regs *regs, unsigned long vaddr); extern int pre_xol(struct uprobe *uprobe, struct pt_regs *regs); extern int post_xol(struct uprobe *uprobe, struct pt_regs *regs); +extern int uprobe_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 40a2493..55db9f5 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>
@@ -844,6 +845,19 @@ 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 8d90ff3..a323631 100644
--- a/arch/x86/kernel/uprobes.c
+++ b/arch/x86/kernel/uprobes.c@@ -560,3 +560,32 @@ int post_xol(struct uprobe *uprobe, struct pt_regs *regs) result = adjust_ret_addr(regs->sp, correction); return result; } + +/* + * Wrapper routine for handling exceptions. + */ +int uprobe_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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