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path: root/arch/x86/kernel/step.c
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2011-08-04x86-64: Add user_64bit_mode paravirt opAndy Lutomirski1-1/+1
Three places in the kernel assume that the only long mode CPL 3 selector is __USER_CS. This is not true on Xen -- Xen's sysretq changes cs to the magic value 0xe033. Two of the places are corner cases, but as of "x86-64: Improve vsyscall emulation CS and RIP handling" (c9712944b2a12373cb6ff8059afcfb7e826a6c54), vsyscalls will segfault if called with Xen's extra CS selector. This causes a panic when older init builds die. It seems impossible to make Xen use __USER_CS reliably without taking a performance hit on every system call, so this fixes the tests instead with a new paravirt op. It's a little ugly because ptrace.h can't include paravirt.h. Signed-off-by: Andy Lutomirski <luto@mit.edu> Link: http://lkml.kernel.org/r/f4fcb3947340d9e96ce1054a432f183f9da9db83.1312378163.git.luto@mit.edu Reported-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2011-03-18x86: Fix common misspellingsLucas De Marchi1-1/+1
They were generated by 'codespell' and then manually reviewed. Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi> Cc: trivial@kernel.org LKML-Reference: <1300389856-1099-3-git-send-email-lucas.demarchi@profusion.mobi> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-26x86, ptrace: Fix block-stepPeter Zijlstra1-4/+20
Implement ptrace-block-step using TIF_BLOCKSTEP which will set DEBUGCTLMSR_BTF when set for a task while preserving any other DEBUGCTLMSR bits. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <20100325135414.017536066@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-26x86, perf, bts, mm: Delete the never used BTS-ptrace codePeter Zijlstra1-32/+4
Support for the PMU's BTS features has been upstreamed in v2.6.32, but we still have the old and disabled ptrace-BTS, as Linus noticed it not so long ago. It's buggy: TIF_DEBUGCTLMSR is trampling all over that MSR without regard for other uses (perf) and doesn't provide the flexibility needed for perf either. Its users are ptrace-block-step and ptrace-bts, since ptrace-bts was never used and ptrace-block-step can be implemented using a much simpler approach. So axe all 3000 lines of it. That includes the *locked_memory*() APIs in mm/mlock.c as well. Reported-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Roland McGrath <roland@redhat.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Markus Metzger <markus.t.metzger@intel.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Andrew Morton <akpm@linux-foundation.org> LKML-Reference: <20100325135413.938004390@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-07-19x86: Use get_desc_base()Akinobu Mita1-5/+4
Use get_desc_base() to get the base address in desc_struct Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> LKML-Reference: <20090718150853.GA11294@localhost.localdomain> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-07-16x86 ptrace: user-sets-TF nitsRoland McGrath1-0/+13
This closes some arcane holes in single-step handling that can arise only when user programs set TF directly (via popf or sigreturn) and then use vDSO (syscall/sysenter) system call entry. In those entry paths, the clear_TF_reenable case hits and we must check TIF_SINGLESTEP to be sure our bookkeeping stays correct wrt the user's view of TF. Signed-off-by: Roland McGrath <roland@redhat.com>
2008-07-16x86 ptrace: block-step fixRoland McGrath1-6/+16
The enable_single_step() logic bails out early if TF is already set. That skips some of the bookkeeping that keeps things straight. This makes PTRACE_SINGLEBLOCK break the behavior of a user task that was already setting TF itself in user mode. Fix the bookkeeping to notice the old TF setting as it should. Test case at: http://sources.redhat.com/cgi-bin/cvsweb.cgi/~checkout~/tests/ptrace-tests/tests/step-jump-cont-strict.c?cvsroot=systemtap Signed-off-by: Roland McGrath <roland@redhat.com>
2008-04-17x86: prevent unconditional writes to DebugCtl MSRJan Beulich1-1/+1
Otherwise, enabling (or better, subsequent disabling) of single stepping would cause a kernel oops on CPUs not having this MSR. The patch could have been added a conditional to the MSR write in user_disable_single_step(), but centralizing the updates seems safer and (looking forward) better manageable. Signed-off-by: Jan Beulich <jbeulich@novell.com> Cc: Markus Metzger <markus.t.metzger@intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-04-03x86 ptrace: avoid unnecessary wrmsrRoland McGrath1-4/+7
This avoids using wrmsr on MSR_IA32_DEBUGCTLMSR when it's not needed. No wrmsr ever needs to be done if noone has ever used block stepping. Without this change, using ptrace on 2.6.25 on an x86 KVM guest will tickle KVM's missing support for the MSR and crash the guest kernel. Though host KVM is the buggy one, this makes for a regression in the guest behavior from 2.6.24->2.6.25 that we can easily avoid. I also corrected some bad whitespace. Signed-off-by: Roland McGrath <roland@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-03-07x86: fix typo in step.cJan Beulich1-2/+2
TIF_DEBUGCTLMSR has no meaning in the actual MSR... Signed-off-by: Jan Beulich <jbeulich@novell.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-01-30x86: remove last user of get_segment_eipHarvey Harrison1-84/+0
is_prefetch was the last user of get_segment_eip and only on X86_32. This function returned the faulting instruction's address and set the upper segment limit. Instead, use the convert_ip_to_linear helper and rely on probe_kernel_address to do the segment checks which was already done everywhere the segment limit was being checked on X86_32. Remove get_segment_eip as well. 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: common x86_32|64 namingHarvey Harrison1-2/+2
Rename convert_rip_to_linear to convert_ip_to_linear for shared X86_32|64 use. 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: use wrmsrl in kprobes.c, step.cHarvey Harrison1-4/+0
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: move get_segment_eip() to step.cHarvey Harrison1-0/+81
get_segment_eip has similarities to convert_rip_to_linear(), and is used in a similar context. Move get_segment_eip to step.c to allow easier consolidation. 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, ptrace: support for branch trace store(BTS)Markus Metzger1-5/+13
Resend using different mail client Changes to the last version: - split implementation into two layers: ds/bts and ptrace - renamed TIF's - save/restore ds save area msr in __switch_to_xtra() - make block-stepping only look at BTF bit Signed-off-by: Markus Metzger <markus.t.metzger@intel.com> Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-30x86: rename the struct pt_regs members for 32/64-bit consistencyH. Peter Anvin1-10/+5
We have a lot of code which differs only by the naming of specific members of structures that contain registers. In order to enable additional unifications, this patch drops the e- or r- size prefix from the register names in struct pt_regs, and drops the x- prefixes for segment registers on the 32-bit side. This patch also performs the equivalent renames in some additional places that might be candidates for unification in the future. Signed-off-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-30x86: debugctlmsr arch_has_block_stepRoland McGrath1-3/+61
This implements user-mode step-until-branch on x86 using the BTF bit in MSR_IA32_DEBUGCTLMSR. It's just like single-step, only less so. Signed-off-by: Roland McGrath <roland@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-30x86 single_step: TIF_FORCED_TFRoland McGrath1-6/+3
This changes the single-step support to use a new thread_info flag TIF_FORCED_TF instead of the PT_DTRACE flag in task_struct.ptrace. This keeps arch implementation uses out of this non-arch field. This changes the ptrace access to eflags to mask TF and maintain the TIF_FORCED_TF flag directly if userland sets TF, instead of relying on ptrace_signal_deliver. The 64-bit and 32-bit kernels are harmonized on this same behavior. The ptrace_signal_deliver approach works now, but this change makes the low-level register access code reliable when called from different contexts than a ptrace stop, which will be possible in the future. The 64-bit do_debug exception handler is also changed not to clear TF from user-mode registers. This matches the 32-bit kernel's behavior. Signed-off-by: Roland McGrath <roland@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-30x86: single_step: share codeRoland McGrath1-0/+14
This removes the single-step code from ptrace_32.c and uses the step.c code shared with the 64-bit kernel. The two versions of the code were nearly identical already, so the shared code has only a couple of simple #ifdef's. Signed-off-by: Roland McGrath <roland@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-30x86: single_step 0xf0Roland McGrath1-1/+1
This fixes the 64-bit single-step handling code's instruction decoder to grok the 0xf0 (lock) prefix, which the 32-bit code already does correctly. Signed-off-by: Roland McGrath <roland@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-30x86: single_step segment macrosRoland McGrath1-3/+1
This cleans up the single-step code to use the asm/segment.h macros for segment selector magic bits, rather than its own constant. Signed-off-by: Roland McGrath <roland@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-30x86: single_step movedRoland McGrath1-0/+140
This moves the single-step support code from ptrace_64.c into a new file step.c, verbatim. This paves the way for consolidating this code between 64-bit and 32-bit versions. Signed-off-by: Roland McGrath <roland@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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