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path: root/arch/x86/kernel/kprobes.c
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2008-02-19x86, kprobes: remove sparse warnings from x86Harvey Harrison
arch/x86/kernel/kprobes.c:584:16: warning: symbol 'kretprobe_trampoline_holder' was not declared. Should it be static? arch/x86/kernel/kprobes.c:676:6: warning: symbol 'trampoline_handler' was not declared. Should it be static? Make them static and add the __used attribute, approach taken from the arm kprobes implementation. kretprobe_trampoline_holder uses inline assemly to define the global symbol kretprobe_trampoline, but nothing ever calls the holder explicitly. trampoline handler is only called from inline assembly in the same file, mark it used and static. Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> Acked-by: Masami Hiramatsu <mhiramat@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-30x86: remove unneded castsJan Engelhardt
x86: remove unneeded casts Signed-off-by: Jan Engelhardt <jengelh@computergmbh.de> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-30x86: fix singlestep handling in reenter_kprobeAbhishek Sagar
Highlight peculiar cases in singles-step kprobe handling. In reenter_kprobe(), a breakpoint in KPROBE_HIT_SS case can only occur when single-stepping a breakpoint on which a probe was installed. Since such probes are single-stepped inline, identifying these cases is unambiguous. All other cases leading up to KPROBE_HIT_SS are possible bugs. Identify and WARN_ON such cases. Signed-off-by: Abhishek Sagar <sagar.abhishek@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-30x86: use wrmsrl in kprobes.c, step.cHarvey Harrison
Where x86_32 passed zero in the high 32 bits, use wrmsrl which will zero extend for us. This allows ifdefs for 32/64 bit to be eliminated. Eliminate ifdef in step.c. Similar cleanup was done when unifying kprobes_32|64.c and wrmsr() was chosen there over wrmsrl(). This patch changes these to wrmsrl. Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-30x86: trivial whitespace in kprobes.cHarvey Harrison
Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> Acked-by: Masami Hiramatsu <mhiramat@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-30x86: kprobes change kprobe_handler flowAbhishek Sagar
Signed-off-by: Abhishek Sagar <sagar.abhishek@gmail.com> Signed-off-by: Quentin Barnes <qbarnes@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-30x86: code clarification patch to Kprobes arch codeQuentin Barnes
When developing the Kprobes arch code for ARM, I ran across some code found in x86 and s390 Kprobes arch code which I didn't consider as good as it could be. Once I figured out what the code was doing, I changed the code for ARM Kprobes to work the way I felt was more appropriate. I've tested the code this way in ARM for about a year and would like to push the same change to the other affected architectures. The code in question is in kprobe_exceptions_notify() which does: ==== /* kprobe_running() needs smp_processor_id() */ preempt_disable(); if (kprobe_running() && kprobe_fault_handler(args->regs, args->trapnr)) ret = NOTIFY_STOP; preempt_enable(); ==== For the moment, ignore the code having the preempt_disable()/ preempt_enable() pair in it. The problem is that kprobe_running() needs to call smp_processor_id() which will assert if preemption is enabled. That sanity check by smp_processor_id() makes perfect sense since calling it with preemption enabled would return an unreliable result. But the function kprobe_exceptions_notify() can be called from a context where preemption could be enabled. If that happens, the assertion in smp_processor_id() happens and we're dead. So what the original author did (speculation on my part!) is put in the preempt_disable()/preempt_enable() pair to simply defeat the check. Once I figured out what was going on, I considered this an inappropriate approach. If kprobe_exceptions_notify() is called from a preemptible context, we can't be in a kprobe processing context at that time anyways since kprobes requires preemption to already be disabled, so just check for preemption enabled, and if so, blow out before ever calling kprobe_running(). I wrote the ARM kprobe code like this: ==== /* To be potentially processing a kprobe fault and to * trust the result from kprobe_running(), we have * be non-preemptible. */ if (!preemptible() && kprobe_running() && kprobe_fault_handler(args->regs, args->trapnr)) ret = NOTIFY_STOP; ==== The above code has been working fine for ARM Kprobes for a year. So I changed the x86 code (2.6.24-rc6) to be the same way and ran the Systemtap tests on that kernel. As on ARM, Systemtap on x86 comes up with the same test results either way, so it's a neutral external functional change (as expected). This issue has been discussed previously on linux-arm-kernel and the Systemtap mailing lists. Pointers to the by base for the two discussions: http://lists.arm.linux.org.uk/lurker/message/20071219.223225.1f5c2a5e.en.html http://sourceware.org/ml/systemtap/2007-q1/msg00251.html Signed-off-by: Quentin Barnes <qbarnes@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Ananth N Mavinakayahanalli <ananth@in.ibm.com> Acked-by: Ananth N Mavinakayahanalli <ananth@in.ibm.com>
2008-01-30x86: kprobes change kprobe_handler flowHarvey Harrison
Make the control flow of kprobe_handler more obvious. Collapse the separate if blocks/gotos with if/else blocks this unifies the duplication of the check for a breakpoint instruction race with another cpu. Create two jump targets: preempt_out: re-enables preemption before returning ret out: only returns ret Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-30x86: kprobes remove fix_riprel #ifdefHarvey Harrison
Move #ifdef around function definiton into the function and unconditionally return on X86_32. Saves an ifdef from the one callsite. [ mingo@elte.hu: minor cleanup. ] Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-30x86: introduce REX prefix helper for kprobesHarvey Harrison
Fold some small ifdefs into a helper function. Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-30x86: move deeply indented code to reenter_kprobeMasami Hiramatsu
Move some deeply indented code related to re-entrance processing from kprobe_handler() to reenter_kprobe(). Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Jim Keniston <jkenisto@us.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-30x86: add reenter_kprobe helperHarvey Harrison
[ mhiramat@redhat.com: updated it to latest x86.git ] Factor common X86_32, X86_64 kprobe reenter logic from deeply indented section to helper function. Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Jim Keniston <jkenisto@us.ibm.com>
2008-01-30x86: fix kprobe_handler reenable preemptionMasami Hiramatsu
Fix a preemption bug in kprobe_handler(). It has to call preempt_enable() before returning. Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-30x86: kprobes leftover cleanupsHarvey Harrison
Eliminate __always_inline, all of these static functions are only called once. Minor whitespace cleanup. Eliminate one supefluous return at end of void function. Change the one #ifndef to #ifdef to match the sense of the rest of the config tests. Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> Acked-by: Masami Hiramatsu <mhiramat@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-30x86: unify extable_{32|64}.cHarvey Harrison
Introduce fixup_exception() on 64-bit and use it in kprobes to eliminate an #ifdef. Only 64-bit needs search_extable() due to a stepping bug. Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-30x86: get rid of _MASK flagsGlauber de Oliveira Costa
There's no need for the *_MASK flags (TF_MASK, IF_MASK, etc), found in processor.h (both _32 and _64). They have a one-to-one mapping with the EFLAGS value. This patch removes the definitions, and use the already existent X86_EFLAGS_ version when applicable. [ roland@redhat.com: KVM build fixes. ] Signed-off-by: Glauber de Oliveira Costa <gcosta@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-30x86: kprobes code for x86 unificationMasami Hiramatsu
This patch unifies kprobes code. - Unify kprobes_*.h to kprobes.h - Unify kprobes_*.c to kprobes.c (Differences are separated by ifdefs) - Most differences are related to REX prefix and rip relatives. - Two inline assembly code are different. - One difference in kprobe_handlre() - One fixup exception code is different, but it will be unified if mm/extable_*.c are unified. - Merge history logs into arch/x86/kernel/kprobes.c. Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com> Signed-off-by: Jim Keniston <jkenisto@us.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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