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path: root/arch/i386/kernel/ptrace.c
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2007-02-13[PATCH] i386: Convert i386 PDA code to use %fsJeremy Fitzhardinge
Convert the PDA code to use %fs rather than %gs as the segment for per-processor data. This is because some processors show a small but measurable performance gain for reloading a NULL segment selector (as %fs generally is in user-space) versus a non-NULL one (as %gs generally is). On modern processors the difference is very small, perhaps undetectable. Some old AMD "K6 3D+" processors are noticably slower when %fs is used rather than %gs; I have no idea why this might be, but I think they're sufficiently rare that it doesn't matter much. This patch also fixes the math emulator, which had not been adjusted to match the changed struct pt_regs. [frederik.deweerdt@gmail.com: fixit with gdb] [mingo@elte.hu: Fix KVM too] Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com> Signed-off-by: Andi Kleen <ak@suse.de> Cc: Ian Campbell <Ian.Campbell@XenSource.com> Acked-by: Ingo Molnar <mingo@elte.hu> Acked-by: Zachary Amsden <zach@vmware.com> Cc: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: Frederik Deweerdt <frederik.deweerdt@gmail.com> Signed-off-by: Andrew Morton <akpm@osdl.org>
2006-12-22[PATCH] ptrace: Fix EFL_OFFSET value according to i386 pda changesJeremy Fitzhardinge
The PDA patches introduced a bug in ptrace: it reads eflags from the wrong place on the target's stack, but writes it back to the correct place. The result is a corrupted eflags, which is most visible when it turns interrupts off unexpectedly. This patch fixes this by making the ptrace code a little less fragile. It changes [gs]et_stack_long to take a straightforward byte offset into struct pt_regs, rather than requiring all callers to do a sizeof(struct pt_regs) offset adjustment. This means that the eflag's offset (EFL_OFFSET) on the target stack can be simply computed with offsetof(). Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com> Cc: Frederik Deweerdt <deweerdt@free.fr> Cc: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-07[PATCH] i386: Fix places where using %gs changes the usermode ABIJeremy Fitzhardinge
There are a few places where the change in struct pt_regs and the use of %gs affect the userspace ABI. These are primarily debugging interfaces where thread state can be inspected or extracted. Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com> Signed-off-by: Andi Kleen <ak@suse.de> Cc: Chuck Ebbert <76306.1226@compuserve.com> Cc: Zachary Amsden <zach@vmware.com> Cc: Jan Beulich <jbeulich@novell.com> Cc: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org>
2006-09-26[PATCH] i386/x86-64: rename is_at_popf(), add iret to tests and fixChuck Ebbert
is_at_popf() needs to test for the iret instruction as well as popf. So add that test and rename it to is_setting_trap_flag(). Also change max insn length from 16 to 15 to match reality. LAHF / SAHF can't affect TF, so the comment in x86_64 is removed. Signed-off-by: Chuck Ebbert <76306.1226@compuserve.com> Signed-off-by: Andi Kleen <ak@suse.de>
2006-07-09[PATCH] i386: use thread_info flags for debug regs and IO bitmapsStephane Eranian
Use thread info flags to track use of debug registers and IO bitmaps. - add TIF_DEBUG to track when debug registers are active - add TIF_IO_BITMAP to track when I/O bitmap is used - modify __switch_to() to use the new TIF flags Performance tested on Pentium II, ten runs of LMbench context switch benchmark (smaller is better:) before after avg 3.65 3.39 min 3.55 3.33 Signed-off-by: Stephane Eranian <eranian@hpl.hp.com> Signed-off-by: Chuck Ebbert <76306.1226@compuserve.com> Acked-by: Andi Kleen <ak@suse.de> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-05-01[PATCH] drop task argument of audit_syscall_{entry,exit}Al Viro
... it's always current, and that's a good thing - allows simpler locking. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2006-03-23[PATCH] i386: Don't let ptrace set the nested task bitChuck Ebbert
There's no good reason for allowing ptrace to set the NT bit in EFLAGS, so mask it off. Signed-off-by: Chuck Ebbert <76306.1226@compuserve.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-05[PATCH] i386: PTRACE_POKEUSR: allow changing RF bit in EFLAGS register.Chuck Ebbert
Setting RF (resume flag) allows a debugger to resume execution after a code breakpoint without tripping the breakpoint again. It is reset by the CPU after execution of one instruction. Requested by Stephane Eranian: "I am trying to the user HW debug registers on i386 and I am running into a problem with ptrace() not allowing access to EFLAGS_RF for POKEUSER (see FLAG_MASK). [ ... ] It avoids the need to remove the breakpoint, single step, and reinstall. The equivalent functionality exists on IA-64 and is allowed by ptrace()" Cc: Stephane Eranian <eranian@hpl.hp.com> Signed-off-by: Chuck Ebbert <76306.1226@compuserve.com> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-07[PATCH] consolidate sys_ptrace()Christoph Hellwig
The sys_ptrace boilerplate code (everything outside the big switch statement for the arch-specific requests) is shared by most architectures. This patch moves it to kernel/ptrace.c and leaves the arch-specific code as arch_ptrace. Some architectures have a too different ptrace so we have to exclude them. They continue to keep their implementations. For sh64 I had to add a sh64_ptrace wrapper because it does some initialization on the first call. For um I removed an ifdefed SUBARCH_PTRACE_SPECIAL block, but SUBARCH_PTRACE_SPECIAL isn't defined anywhere in the tree. Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Paul Mackerras <paulus@samba.org> Acked-by: Ralf Baechle <ralf@linux-mips.org> Acked-By: David Howells <dhowells@redhat.com> Acked-by: Russell King <rmk+kernel@arm.linux.org.uk> Acked-by: Paul Mundt <lethal@linux-sh.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30[PATCH] unify sys_ptrace prototypeChristoph Hellwig
Make sure we always return, as all syscalls should. Also move the common prototype to <linux/syscalls.h> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-09[PATCH] i386: seccomp fix for auditing/ptraceAndrea Arcangeli
This is the same issue as ppc64 before, when returning to userland we shouldn't re-compute the seccomp check or the task could be killed during sigreturn when orig_eax is overwritten by the sigreturn syscall. This was found by Roland. This was harmless from a security standpoint, but some i686 users reported failures with auditing enabled system wide (some distro surprisingly makes it the default) and I reproduced it too by keeping the whole workload under strace -f. Patch is tested and works for me under strace -f. nobody@athlon:~/cpushare> strace -o /tmp/o -f python seccomp_test.py make: Nothing to be done for `seccomp_test'. Starting computing some malicious bytecode init load start stop receive_data failure kill exit_code 0 signal 9 The malicious bytecode has been killed successfully by seccomp Starting computing some safe bytecode init load start stop 174 counts kill exit_code 0 signal 0 The seccomp_test.py completed successfully, thank you for testing. (akpm: collaterally cleaned up a bit of do_syscall_trace() too) Signed-off-by: Andrea Arcangeli <andrea@cpushare.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-05[PATCH] SYSEMU: fix sysaudit / singlestep interactionBodo Stroesser
Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> This is simply an adjustment for "Ptrace - i386: fix Syscall Audit interaction with singlestep" to work on top of SYSEMU patches, too. On this patch, I have some doubts: I wonder why we need to alter that way ptrace_disable(). I left the patch this way because it has been extensively tested, but I don't understand the reason. The current PTRACE_DETACH handling simply clears child->ptrace; actually this is not enough because entry.S just looks at the thread_flags; actually, do_syscall_trace checks current->ptrace but I don't think depending on that is good, at least for performance, so I think the clearing is done elsewhere. For instance, on PTRACE_CONT it's done, but doing PTRACE_DETACH without PTRACE_CONT is possible (and happens when gdb crashes and one kills it manually). Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> CC: Roland McGrath <roland@redhat.com> Cc: Jeff Dike <jdike@addtoit.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-05[PATCH] Uml support: add PTRACE_SYSEMU_SINGLESTEP option to i386Bodo Stroesser
This patch implements the new ptrace option PTRACE_SYSEMU_SINGLESTEP, which can be used by UML to singlestep a process: it will receive SINGLESTEP interceptions for normal instructions and syscalls, but syscall execution will be skipped just like with PTRACE_SYSEMU. Signed-off-by: Bodo Stroesser <bstroesser@fujitsu-siemens.com> Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Cc: Jeff Dike <jdike@addtoit.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-05[PATCH] Uml support: reorganize PTRACE_SYSEMU supportBodo Stroesser
With this patch, we change the way we handle switching from PTRACE_SYSEMU to PTRACE_{SINGLESTEP,SYSCALL}, to free TIF_SYSCALL_EMU from double use as a preparation for PTRACE_SYSEMU_SINGLESTEP extension, without changing the behavior of the host kernel. Signed-off-by: Bodo Stroesser <bstroesser@fujitsu-siemens.com> Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Cc: Jeff Dike <jdike@addtoit.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-05[PATCH] UML Support - Ptrace: adds the host SYSEMU support, for UML and ↵Laurent Vivier
general usage Jeff Dike <jdike@addtoit.com>, Paolo 'Blaisorblade' Giarrusso <blaisorblade_spam@yahoo.it>, Bodo Stroesser <bstroesser@fujitsu-siemens.com> Adds a new ptrace(2) mode, called PTRACE_SYSEMU, resembling PTRACE_SYSCALL except that the kernel does not execute the requested syscall; this is useful to improve performance for virtual environments, like UML, which want to run the syscall on their own. In fact, using PTRACE_SYSCALL means stopping child execution twice, on entry and on exit, and each time you also have two context switches; with SYSEMU you avoid the 2nd stop and so save two context switches per syscall. Also, some architectures don't have support in the host for changing the syscall number via ptrace(), which is currently needed to skip syscall execution (UML turns any syscall into getpid() to avoid it being executed on the host). Fixing that is hard, while SYSEMU is easier to implement. * This version of the patch includes some suggestions of Jeff Dike to avoid adding any instructions to the syscall fast path, plus some other little changes, by myself, to make it work even when the syscall is executed with SYSENTER (but I'm unsure about them). It has been widely tested for quite a lot of time. * Various fixed were included to handle the various switches between various states, i.e. when for instance a syscall entry is traced with one of PT_SYSCALL / _SYSEMU / _SINGLESTEP and another one is used on exit. Basically, this is done by remembering which one of them was used even after the call to ptrace_notify(). * We're combining TIF_SYSCALL_EMU with TIF_SYSCALL_TRACE or TIF_SINGLESTEP to make do_syscall_trace() notice that the current syscall was started with SYSEMU on entry, so that no notification ought to be done in the exit path; this is a bit of a hack, so this problem is solved in another way in next patches. * Also, the effects of the patch: "Ptrace - i386: fix Syscall Audit interaction with singlestep" are cancelled; they are restored back in the last patch of this series. Detailed descriptions of the patches doing this kind of processing follow (but I've already summed everything up). * Fix behaviour when changing interception kind #1. In do_syscall_trace(), we check the status of the TIF_SYSCALL_EMU flag only after doing the debugger notification; but the debugger might have changed the status of this flag because he continued execution with PTRACE_SYSCALL, so this is wrong. This patch fixes it by saving the flag status before calling ptrace_notify(). * Fix behaviour when changing interception kind #2: avoid intercepting syscall on return when using SYSCALL again. A guest process switching from using PTRACE_SYSEMU to PTRACE_SYSCALL crashes. The problem is in arch/i386/kernel/entry.S. The current SYSEMU patch inhibits the syscall-handler to be called, but does not prevent do_syscall_trace() to be called after this for syscall completion interception. The appended patch fixes this. It reuses the flag TIF_SYSCALL_EMU to remember "we come from PTRACE_SYSEMU and now are in PTRACE_SYSCALL", since the flag is unused in the depicted situation. * Fix behaviour when changing interception kind #3: avoid intercepting syscall on return when using SINGLESTEP. When testing 2.6.9 and the skas3.v6 patch, with my latest patch and had problems with singlestepping on UML in SKAS with SYSEMU. It looped receiving SIGTRAPs without moving forward. EIP of the traced process was the same for all SIGTRAPs. What's missing is to handle switching from PTRACE_SYSCALL_EMU to PTRACE_SINGLESTEP in a way very similar to what is done for the change from PTRACE_SYSCALL_EMU to PTRACE_SYSCALL_TRACE. I.e., after calling ptrace(PTRACE_SYSEMU), on the return path, the debugger is notified and then wake ups the process; the syscall is executed (or skipped, when do_syscall_trace() returns 0, i.e. when using PTRACE_SYSEMU), and do_syscall_trace() is called again. Since we are on the return path of a SYSEMU'd syscall, if the wake up is performed through ptrace(PTRACE_SYSCALL), we must still avoid notifying the parent of the syscall exit. Now, this behaviour is extended even to resuming with PTRACE_SINGLESTEP. Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Cc: Jeff Dike <jdike@addtoit.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-05[PATCH] Ptrace/i386: fix "syscall audit" interaction with singlestepBodo Stroesser
Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Avoid giving two traps for singlestep instead of one, when syscall auditing is enabled. In fact no singlestep trap is sent on syscall entry, only on syscall exit, as can be seen in entry.S: # Note that in this mask _TIF_SINGLESTEP is not tested !!! <<<<<<<<<<<<<< testb $(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|_TIF_SECCOMP),TI_flags(%ebp) jnz syscall_trace_entry ... syscall_trace_entry: ... call do_syscall_trace But auditing a SINGLESTEP'ed process causes do_syscall_trace to be called, so the tracer will get one more trap on the syscall entry path, which it shouldn't. Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> CC: Roland McGrath <roland@redhat.com> Cc: Jeff Dike <jdike@addtoit.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-23[PATCH] xen: x86: Rename usermode macroVincent Hanquez
Rename user_mode to user_mode_vm and add a user_mode macro similar to the x86-64 one. This is useful for Xen because the linux xen kernel does not runs on the same priviledge that a vanilla linux kernel, and with this we just need to redefine user_mode(). Signed-off-by: Vincent Hanquez <vincent.hanquez@cl.cam.ac.uk> Cc: Ian Pratt <m+Ian.Pratt@cl.cam.ac.uk> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-05-03Merge with master.kernel.org:/pub/scm/linux/kernel/git/torvalds/linux-2.6.gitDavid Woodhouse
2005-05-01[PATCH] convert that currently tests _NSIG directly to use valid_signal()Jesper Juhl
Convert most of the current code that uses _NSIG directly to instead use valid_signal(). This avoids gcc -W warnings and off-by-one errors. Signed-off-by: Jesper Juhl <juhl-lkml@dif.dk> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-04-29[AUDIT] Don't allow ptrace to fool auditing, log arch of audited syscalls.
We were calling ptrace_notify() after auditing the syscall and arguments, but the debugger could have _changed_ them before the syscall was actually invoked. Reorder the calls to fix that. While we're touching ever call to audit_syscall_entry(), we also make it take an extra argument: the architecture of the syscall which was made, because some architectures allow more than one type of syscall. Also add an explicit success/failure flag to audit_syscall_exit(), for the benefit of architectures which return that in a condition register rather than only returning a single register. Change type of syscall return value to 'long' not 'int'. Signed-off-by: David Woodhouse <dwmw2@infradead.org>
2005-04-16Linux-2.6.12-rc2Linus Torvalds
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!