- 30 10月, 2010 1 次提交
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由 Jason Baron 提交于
Currently, text_poke_smp() passes a NULL as the third argument to __stop_machine(), which will only run stop_machine_text_poke() on 1 cpu. Change NULL -> cpu_online_mask, as stop_machine_text_poke() is intended to be run on all cpus. I actually didn't notice any problems with stop_machine_text_poke() only being called on 1 cpu, but found this via code inspection. Signed-off-by: NJason Baron <jbaron@redhat.com> LKML-Reference: <20101028152026.GB2875@redhat.com> Acked-by: NMathieu Desnoyers <mathieu.desnoyers@efficios.com> Acked-by: NMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>
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- 14 10月, 2010 1 次提交
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由 Masami Hiramatsu 提交于
Use __stop_machine() in text_poke_smp() because the caller must get online_cpus before calling text_poke_smp(), but stop_machine() do it again. We don't need it. Signed-off-by: NMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: 2nddept-manager@sdl.hitachi.co.jp Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> LKML-Reference: <20101014031036.4100.83989.stgit@ltc236.sdl.hitachi.co.jp> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 23 9月, 2010 1 次提交
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由 Jason Baron 提交于
base patch to implement 'jump labeling'. Based on a new 'asm goto' inline assembly gcc mechanism, we can now branch to labels from an 'asm goto' statment. This allows us to create a 'no-op' fastpath, which can subsequently be patched with a jump to the slowpath code. This is useful for code which might be rarely used, but which we'd like to be able to call, if needed. Tracepoints are the current usecase that these are being implemented for. Acked-by: NDavid S. Miller <davem@davemloft.net> Signed-off-by: NJason Baron <jbaron@redhat.com> LKML-Reference: <ee8b3595967989fdaf84e698dc7447d315ce972a.1284733808.git.jbaron@redhat.com> [ cleaned up some formating ] Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
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- 21 9月, 2010 2 次提交
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由 Jason Baron 提交于
Make text_poke_early available outside of alternative.c. The jump label patchset wants to make use of it in order to set up the optimal no-op sequences at run-time. Signed-off-by: NJason Baron <jbaron@redhat.com> LKML-Reference: <04cfddf2ba77bcabfc3e524f1849d871d6a1cf9d.1284733808.git.jbaron@redhat.com> Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
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由 Jason Baron 提交于
Move Steve's code for finding the best 5-byte no-op from ftrace.c to alternative.c. The idea is that other consumers (in this case jump label) want to make use of that code. Signed-off-by: NJason Baron <jbaron@redhat.com> LKML-Reference: <96259ae74172dcac99c0020c249743c523a92e18.1284733808.git.jbaron@redhat.com> Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
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- 14 7月, 2010 1 次提交
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由 H. Peter Anvin 提交于
Make the alternatives-patching code BUG on encountering an invalid CPU feature number. Should have done this a long time ago. Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com> Cc: Yinghai Lu <yinhai@kernel.org> Cc: Suresh Siddha <suresh.b.siddha@intel.com> LKML-Reference: <tip-df378ccf@git.kernel.org>
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- 29 4月, 2010 1 次提交
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由 Jan Beulich 提交于
Reduce the SMP locks table size by using relative pointers instead of absolute ones, thus cutting the table size by half. Signed-off-by: NJan Beulich <jbeulich@novell.com> LKML-Reference: <4BCF30FE020000780003B3B6@vpn.id2.novell.com> Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
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- 30 3月, 2010 1 次提交
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由 Tejun Heo 提交于
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: NTejun Heo <tj@kernel.org> Guess-its-ok-by: NChristoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
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- 04 3月, 2010 1 次提交
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由 Masami Hiramatsu 提交于
Fix stop_machine_text_poke() to issue smp_mb() before exiting waiting loop, and use cpu_relax() for waiting. Changes in v2: - Don't use ACCESS_ONCE(). Signed-off-by: NMasami Hiramatsu <mhiramat@redhat.com> Acked-by: NMathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: systemtap <systemtap@sources.redhat.com> Cc: DLE <dle-develop@lists.sourceforge.net> Cc: Jason Baron <jbaron@redhat.com> LKML-Reference: <20100304033850.3819.74590.stgit@localhost6.localdomain6> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 26 2月, 2010 2 次提交
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由 Luca Barbieri 提交于
The current lock prefix UP/SMP alternative code doesn't allow LOCK_PREFIX to be used in alternatives code. This patch solves the problem by adding a new LOCK_PREFIX_ALTERNATIVE_PATCH macro that only records the lock prefix location but does not emit the prefix. The user of this macro can then start any alternative sequence with "lock" and have it UP/SMP patched. To make this work, the UP/SMP alternative code is changed to do the lock/DS prefix switching only if the byte actually contains a lock or DS prefix. Thus, if an alternative without the "lock" is selected, it will now do nothing instead of clobbering the code. Changes in v2: - Naming change - Change label to not conflict with alternatives Signed-off-by: NLuca Barbieri <luca@luca-barbieri.com> LKML-Reference: <1267005265-27958-2-git-send-email-luca@luca-barbieri.com> Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
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由 Masami Hiramatsu 提交于
Add generic text_poke_smp for SMP which uses stop_machine() to synchronize modifying code. This stop_machine() method is officially described at "7.1.3 Handling Self- and Cross-Modifying Code" on the intel's software developer's manual 3A. Since stop_machine() can't protect code against NMI/MCE, this function can not modify those handlers. And also, this function is basically for modifying multibyte-single-instruction. For modifying multibyte-multi-instructions, we need another special trap & detour code. This code originaly comes from immediate values with stop_machine() version. Thanks Jason and Mathieu! Signed-off-by: NMasami Hiramatsu <mhiramat@redhat.com> Cc: systemtap <systemtap@sources.redhat.com> Cc: DLE <dle-develop@lists.sourceforge.net> Cc: Mathieu Desnoyers <compudj@krystal.dyndns.org> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Jim Keniston <jkenisto@us.ibm.com> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Anders Kaseorg <andersk@ksplice.com> Cc: Tim Abbott <tabbott@ksplice.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Jason Baron <jbaron@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> LKML-Reference: <20100225133438.6725.80273.stgit@localhost6.localdomain6> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 08 2月, 2010 1 次提交
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由 Masami Hiramatsu 提交于
Fixes these warnings: arch/x86/kernel/alternative.c: In function 'alternatives_text_reserved': arch/x86/kernel/alternative.c:402: warning: comparison of distinct pointer types lacks a cast arch/x86/kernel/alternative.c:402: warning: comparison of distinct pointer types lacks a cast arch/x86/kernel/alternative.c:405: warning: comparison of distinct pointer types lacks a cast arch/x86/kernel/alternative.c:405: warning: comparison of distinct pointer types lacks a cast Caused by: 2cfa1978: ftrace/alternatives: Introducing *_text_reserved functions Changes in v2: - Use local variables to compare, instead of type casts. Reported-by: NIngo Molnar <mingo@elte.hu> Signed-off-by: NMasami Hiramatsu <mhiramat@redhat.com> Cc: systemtap <systemtap@sources.redhat.com> Cc: DLE <dle-develop@lists.sourceforge.net> LKML-Reference: <20100205171647.15750.37221.stgit@dhcp-100-2-132.bos.redhat.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 04 2月, 2010 1 次提交
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由 Masami Hiramatsu 提交于
Introducing *_text_reserved functions for checking the text address range is partially reserved or not. This patch provides checking routines for x86 smp alternatives and dynamic ftrace. Since both functions modify fixed pieces of kernel text, they should reserve and protect those from other dynamic text modifier, like kprobes. This will also be extended when introducing other subsystems which modify fixed pieces of kernel text. Dynamic text modifiers should avoid those. Signed-off-by: NMasami Hiramatsu <mhiramat@redhat.com> Cc: systemtap <systemtap@sources.redhat.com> Cc: DLE <dle-develop@lists.sourceforge.net> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: przemyslaw@pawelczyk.it Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Jim Keniston <jkenisto@us.ibm.com> Cc: Mathieu Desnoyers <compudj@krystal.dyndns.org> Cc: Jason Baron <jbaron@redhat.com> LKML-Reference: <20100202214911.4694.16587.stgit@dhcp-100-2-132.bos.redhat.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 30 12月, 2009 1 次提交
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由 Jan Beulich 提交于
In order to avoid unnecessary chains of branches, rather than implementing copy_user_generic() as a function consisting of just a single (possibly patched) branch, instead properly deal with patching call instructions in the alternative instructions framework, and move the patching into the callers. As a follow-on, one could also introduce something like __EXPORT_SYMBOL_ALT() to avoid patching call sites in modules. Signed-off-by: NJan Beulich <jbeulich@novell.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> LKML-Reference: <4B2BB8180200007800026AE7@vpn.id2.novell.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 11 9月, 2009 1 次提交
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由 Ben Hutchings 提交于
As reported in <http://bugs.debian.org/511703> and <http://bugs.debian.org/515982>, kernels with paravirt-alternatives enabled crash in text_poke_early() on at least some 486-class processors. The problem is that text_poke_early() itself uses inline functions affected by paravirt-alternatives and so will modify instructions that have already been prefetched. Pentium and later processors will invalidate the prefetched instructions in this case, but 486-class processors do not. Change sync_core() to limit prefetching on 486-class (and 386-class) processors, and move the call to sync_core() above the call to the modifiable local_irq_restore(). Signed-off-by: NBen Hutchings <ben@decadent.org.uk> LKML-Reference: <1252547631.3423.134.camel@localhost> Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
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- 22 8月, 2009 1 次提交
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由 Jan Beulich 提交于
Some of the NOPs tables aren't used on 64-bits, quite some code and data is needed post-init for module loading only, and a couple of functions aren't used outside that file (i.e. can be static, and don't need to be exported). The change to __INITDATA/__INITRODATA is needed to avoid an assembler warning. Signed-off-by: NJan Beulich <jbeulich@novell.com> LKML-Reference: <4A8BC8A00200007800010823@vpn.id2.novell.com> Acked-by: NSam Ravnborg <sam@ravnborg.org> Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
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- 10 3月, 2009 1 次提交
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由 Masami Hiramatsu 提交于
Expand irq-off region to cover fixmap using code and cache synchronizing. Signed-off-by: NMasami Hiramatsu <mhiramat@redhat.com> LKML-Reference: <49B54688.8090403@redhat.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 06 3月, 2009 2 次提交
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由 Masami Hiramatsu 提交于
Use fixmaps instead of vmap/vunmap in text_poke() for avoiding page allocation and delayed unmapping. At the result of above change, text_poke() becomes atomic and can be called from stop_machine() etc. Signed-off-by: NMasami Hiramatsu <mhiramat@redhat.com> Acked-by: NMathieu Desnoyers <mathieu.desnoyers@polymtl.ca> LKML-Reference: <49B14352.2040705@redhat.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Masami Hiramatsu 提交于
Use the mutual exclusion provided by the text edit lock in alternatives code. Since alternative_smp_* will be called from module init code, etc, we'd better protect it from other subsystems. Signed-off-by: NMasami Hiramatsu <mhiramat@redhat.com> LKML-Reference: <49B14332.9030109@redhat.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 25 2月, 2009 1 次提交
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由 Peter Zijlstra 提交于
Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 18 2月, 2009 1 次提交
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由 Andi Kleen 提交于
Impact: low priority bug fix This removes part of a a patch I added myself some time ago. After some consideration the patch was a bad idea. In particular it stopped machine check exceptions during code patching. To quote the comment: * MCEs only happen when something got corrupted and in this * case we must do something about the corruption. * Ignoring it is worse than a unlikely patching race. * Also machine checks tend to be broadcast and if one CPU * goes into machine check the others follow quickly, so we don't * expect a machine check to cause undue problems during to code * patching. So undo the machine check related parts of 8f4e956b NMIs are still disabled. This only removes code, the only additions are a new comment. Signed-off-by: NAndi Kleen <ak@linux.intel.com> Acked-by: NThomas Gleixner <tglx@linutronix.de> Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
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- 13 10月, 2008 1 次提交
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由 Thomas Gleixner 提交于
num_possible_cpus() can be > 1 when disabled CPUs have been accounted. Disabled CPUs are not in the cpu_present_map, so we can use num_present_cpus() as a safe indicator to switch to UP alternatives. Reported-by: NChuck Ebbert <cebbert@redhat.com> Signed-off-by: NThomas Gleixner <tglx@linutronix.de> Cc: <stable@kernel.org> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 06 9月, 2008 1 次提交
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由 H. Peter Anvin 提交于
Use X86_FEATURE_NOPL to determine if it is safe to use P6 NOPs in alternatives. Also, replace table and loop with simple if statement. Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
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- 19 8月, 2008 1 次提交
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由 H. Peter Anvin 提交于
Use X86_FEATURE_NOPL to determine if it is safe to use P6 NOPs in alternatives. Also, replace table and loop with simple if statement. Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
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- 16 8月, 2008 1 次提交
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由 Mathieu Desnoyers 提交于
If a kernel thread is preempted in single-cpu mode right after the NOP (nop about to be turned into a lock prefix), then we CPU hotplug a CPU, and then the thread is scheduled back again, a SMP-unsafe atomic operation will be used on shared SMP variables, leading to corruption. No corruption would happen in the reverse case : going from SMP to UP is ok because we split a bit instruction into tiny pieces, which does not present this condition. Changing the 0x90 (single-byte nop) currently used into a 0x3E DS segment override prefix should fix this issue. Since the default of the atomic instructions is to use the DS segment anyway, it should not affect the behavior. The exception to this are references that use ESP/RSP and EBP/RBP as the base register (they will use the SS segment), however, in Linux (a) DS == SS at all times, and (b) we do not distinguish between segment violations reported as #SS as opposed to #GP, so there is no need to disassemble the instruction to figure out the suitable segment. This patch assumes that the 0x3E prefix will leave atomic operations as-is (thus assuming they normally touch data in the DS segment). Since there seem to be no obvious ill-use of other segment override prefixes for atomic operations, it should be safe. It can be verified with a quick grep -r LOCK_PREFIX include/asm-x86/ grep -A 1 -r LOCK_PREFIX arch/x86/ Taken from This source : AMD64 Architecture Programmer's Manual Volume 3: General-Purpose and System Instructions States "Instructions that Reference a Non-Stack Segment—If an instruction encoding references any base register other than rBP or rSP, or if an instruction contains an immediate offset, the default segment is the data segment (DS). These instructions can use the segment-override prefix to select one of the non-default segments, as shown in Table 1-5." Therefore, forcing the DS segment on the atomic operations, which already use the DS segment, should not change. This source : http://wiki.osdev.org/X86_Instruction_Encoding States "In 64-bit the CS, SS, DS and ES segment overrides are ignored." Confirmed by "AMD 64-Bit Technology" A.7 http://www.amd.com/us-en/assets/content_type/white_papers_and_tech_docs/x86-64_overview.pdf "In 64-bit mode, the DS, ES, SS and CS segment-override prefixes have no effect. These four prefixes are no longer treated as segment-override prefixes in the context of multipleprefix rules. Instead, they are treated as null prefixes." This patch applies to 2.6.27-rc2, but would also have to be applied to earlier kernels (2.6.26, 2.6.25, ...). Performance impact of the fix : tests done on "xaddq" and "xaddl" shows it actually improves performances on Intel Xeon, AMD64, Pentium M. It does not change the performance on Pentium II, Pentium 3 and Pentium 4. Xeon E5405 2.0GHz : NR_TESTS 10000000 test empty cycles : 162207948 test test 1-byte nop xadd cycles : 170755422 test test DS override prefix xadd cycles : 170000118 * test test LOCK xadd cycles : 472012134 AMD64 2.0GHz : NR_TESTS 10000000 test empty cycles : 146674549 test test 1-byte nop xadd cycles : 150273860 test test DS override prefix xadd cycles : 149982382 * test test LOCK xadd cycles : 270000690 Pentium 4 3.0GHz NR_TESTS 10000000 test empty cycles : 290001195 test test 1-byte nop xadd cycles : 310000560 test test DS override prefix xadd cycles : 310000575 * test test LOCK xadd cycles : 1050103740 Pentium M 2.0GHz NR_TESTS 10000000 test empty cycles : 180000523 test test 1-byte nop xadd cycles : 320000345 test test DS override prefix xadd cycles : 310000374 * test test LOCK xadd cycles : 480000357 Pentium 3 550MHz NR_TESTS 10000000 test empty cycles : 510000231 test test 1-byte nop xadd cycles : 620000128 test test DS override prefix xadd cycles : 620000110 * test test LOCK xadd cycles : 800000088 Pentium II 350MHz NR_TESTS 10000000 test empty cycles : 200833494 test test 1-byte nop xadd cycles : 340000130 test test DS override prefix xadd cycles : 340000126 * test test LOCK xadd cycles : 530000078 Speed test modules can be found at http://ltt.polymtl.ca/svn/trunk/tests/kernel/test-prefix-speed-32.c http://ltt.polymtl.ca/svn/trunk/tests/kernel/test-prefix-speed.c Macro-benchmarks 2.0GHz E5405 Core 2 dual Quad-Core Xeon Summary * replace smp lock prefixes with DS segment selector prefixes no lock prefix (s) with lock prefix (s) Speedup make -j1 kernel/ 33.94 +/- 0.07 34.91 +/- 0.27 2.8 % hackbench 50 2.99 +/- 0.01 3.74 +/- 0.01 25.1 % * replace smp lock prefixes with 0x90 nops no lock prefix (s) with lock prefix (s) Speedup make -j1 kernel/ 34.16 +/- 0.32 34.91 +/- 0.27 2.2 % hackbench 50 3.00 +/- 0.01 3.74 +/- 0.01 24.7 % Detail : 1 CPU, replace smp lock prefixes with DS segment selector prefixes make -j1 kernel/ real 0m34.067s user 0m30.630s sys 0m2.980s real 0m33.867s user 0m30.582s sys 0m3.024s real 0m33.939s user 0m30.738s sys 0m2.876s real 0m33.913s user 0m30.806s sys 0m2.808s avg : 33.94s std. dev. : 0.07s hackbench 50 Time: 2.978 Time: 2.982 Time: 3.010 Time: 2.984 Time: 2.982 avg : 2.99 std. dev. : 0.01 1 CPU, noreplace-smp make -j1 kernel/ real 0m35.326s user 0m30.630s sys 0m3.260s real 0m34.325s user 0m30.802s sys 0m3.084s real 0m35.568s user 0m30.722s sys 0m3.168s real 0m34.435s user 0m30.886s sys 0m2.996s avg.: 34.91s std. dev. : 0.27s hackbench 50 Time: 3.733 Time: 3.750 Time: 3.761 Time: 3.737 Time: 3.741 avg : 3.74 std. dev. : 0.01 1 CPU, replace smp lock prefixes with 0x90 nops make -j1 kernel/ real 0m34.139s user 0m30.782s sys 0m2.820s real 0m34.010s user 0m30.630s sys 0m2.976s real 0m34.777s user 0m30.658s sys 0m2.916s real 0m33.924s user 0m30.634s sys 0m2.924s real 0m33.962s user 0m30.774s sys 0m2.800s real 0m34.141s user 0m30.770s sys 0m2.828s avg : 34.16 std. dev. : 0.32 hackbench 50 Time: 2.999 Time: 2.994 Time: 3.004 Time: 2.991 Time: 2.988 avg : 3.00 std. dev. : 0.01 I did more runs (20 runs of each) to compare the nop case to the DS prefix case. Results in seconds. They actually does not seems to show a significant difference. NOP 34.155 33.955 34.012 35.299 35.679 34.141 33.995 35.016 34.254 33.957 33.957 34.008 35.013 34.494 33.893 34.295 34.314 34.854 33.991 34.132 DS 34.080 34.304 34.374 35.095 34.291 34.135 33.940 34.208 35.276 34.288 33.861 33.898 34.610 34.709 33.851 34.256 35.161 34.283 33.865 35.078 Used http://www.graphpad.com/quickcalcs/ttest1.cfm?Format=C to do the T-test (yeah, I'm lazy) : Group Group One (DS prefix) Group Two (nops) Mean 34.37815 34.37070 SD 0.46108 0.51905 SEM 0.10310 0.11606 N 20 20 P value and statistical significance: The two-tailed P value equals 0.9620 By conventional criteria, this difference is considered to be not statistically significant. Confidence interval: The mean of Group One minus Group Two equals 0.00745 95% confidence interval of this difference: From -0.30682 to 0.32172 Intermediate values used in calculations: t = 0.0480 df = 38 standard error of difference = 0.155 So, unless these calculus are completely bogus, the difference between the nop and the DS case seems not to be statistically significant. Signed-off-by: NMathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Acked-by: NH. Peter Anvin <hpa@zytor.com> CC: Linus Torvalds <torvalds@linux-foundation.org> CC: Jeremy Fitzhardinge <jeremy@goop.org> CC: Roland McGrath <roland@redhat.com> CC: Ingo Molnar <mingo@elte.hu> Cc: Steven Rostedt <rostedt@goodmis.org> CC: Steven Rostedt <srostedt@redhat.com> CC: Thomas Gleixner <tglx@linutronix.de> CC: Peter Zijlstra <peterz@infradead.org> CC: Andrew Morton <akpm@linux-foundation.org> CC: David Miller <davem@davemloft.net> CC: Ulrich Drepper <drepper@redhat.com> CC: Rusty Russell <rusty@rustcorp.com.au> CC: Gregory Haskins <ghaskins@novell.com> CC: Arnaldo Carvalho de Melo <acme@redhat.com> CC: "Luis Claudio R. Goncalves" <lclaudio@uudg.org> CC: Clark Williams <williams@redhat.com> CC: Christoph Lameter <cl@linux-foundation.org> CC: Andi Kleen <andi@firstfloor.org> CC: Harvey Harrison <harvey.harrison@gmail.com> Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
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- 24 5月, 2008 2 次提交
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由 Pekka Paalanen 提交于
text_poke is sleepable. The original fix by Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>. Signed-off-by: NPekka Paalanen <pq@iki.fi> Signed-off-by: NIngo Molnar <mingo@elte.hu> Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
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由 Steven Rostedt 提交于
This patch patches the call to mcount with nops instead of a jmp over the mcount call. Signed-off-by: NSteven Rostedt <srostedt@redhat.com> Signed-off-by: NIngo Molnar <mingo@elte.hu> Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
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- 26 4月, 2008 3 次提交
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由 Ingo Molnar 提交于
Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Mathieu Desnoyers 提交于
Clean up the codepath, remove alignment restrictions and do sanity checking of the end result, to make sure we patched the right site. Signed-off-by: NMathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Jiri Slaby 提交于
kernel_text_address returns true even for modules which is not wanted in text_poke. Use core_kernel_text instead. This is a regression introduced in e587cadd which caused occasionaly crashes after suspend/resume. Signed-off-by: NJiri Slaby <jirislaby@gmail.com> CC: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> CC: Andi Kleen <andi@firstfloor.org> CC: pageexec@freemail.hu CC: H. Peter Anvin <hpa@zytor.com> CC: Jeremy Fitzhardinge <jeremy@goop.org> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 17 4月, 2008 3 次提交
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由 Mathieu Desnoyers 提交于
* Ingo Molnar (mingo@elte.hu) wrote: > > * Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> wrote: > > > The shadow vmap for DEBUG_RODATA kernel text modification uses > > virt_to_page to get the pages from the pointer address. > > > > However, I think vmalloc_to_page would be required in case the page is > > used for modules. > > > > Since only the core kernel text is marked read-only, use > > kernel_text_address() to make sure we only shadow map the core kernel > > text, not modules. > > actually, i think we should mark module text readonly too. > Yes, but in the meantime, the x86 tree would need this patch to make kprobes work correctly on modules. I suspect that without this fix, with the enhanced hotplug and kprobes patch, kprobes will use text_poke to insert breakpoints in modules (vmalloced pages used), which will map the wrong pages and corrupt random kernel locations instead of updating the correct page. Work that would write protect the module pages should clearly be done, but it can come in a later time. We have to make sure we interact correctly with the page allocation debugging, as an example. Here is the patch against x86.git 2.6.25-rc5 : The shadow vmap for DEBUG_RODATA kernel text modification uses virt_to_page to get the pages from the pointer address. However, I think vmalloc_to_page would be required in case the page is used for modules. Since only the core kernel text is marked read-only, use kernel_text_address() to make sure we only shadow map the core kernel text, not modules. Signed-off-by: NMathieu Desnoyers <mathieu.desnoyers@polymtl.ca> CC: akpm@linux-foundation.org Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Mathieu Desnoyers 提交于
Fix a memcpy that should be a text_poke (in apply_alternatives). Use kernel_wp_save/kernel_wp_restore in text_poke to support DEBUG_RODATA correctly and so the CPU HOTPLUG special case can be removed. Add text_poke_early, for alternatives and paravirt boot-time and module load time patching. Changelog: - Fix text_set and text_poke alignment check (mixed up bitwise and and or) - Remove text_set - Export add_nops, so it can be used by others. - Document text_poke_early. - Remove clflush, since it breaks some VIA architectures and is not strictly necessary. - Add kerneldoc to text_poke and text_poke_early. - Create a second vmap instead of using the WP bit to support Xen and VMI. - Move local_irq disable within text_poke and text_poke_early to be able to be sleepable in these functions. Signed-off-by: NMathieu Desnoyers <mathieu.desnoyers@polymtl.ca> CC: Andi Kleen <andi@firstfloor.org> CC: pageexec@freemail.hu CC: H. Peter Anvin <hpa@zytor.com> CC: Jeremy Fitzhardinge <jeremy@goop.org> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Harvey Harrison 提交于
__FUNCTION__ is gcc-specific, use __func__ Signed-off-by: NHarvey Harrison <harvey.harrison@gmail.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 10 4月, 2008 1 次提交
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由 Steven Rostedt 提交于
gcc expects all toplevel assembly to return to the original section type. The code in alteranative.c does not do this. This caused some strange bugs in sched-devel where code would end up in the .rodata section and when the kernel sets the NX bit on all .rodata, the kernel would crash when executing this code. This patch adds a .previous marker to return the code back to the original section. Credit goes to Andrew Pinski for telling me it wasn't a gcc bug but a bug in the toplevel asm code in the kernel. ;-) Signed-off-by: NSteven Rostedt <srostedt@redhat.com> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 30 1月, 2008 3 次提交
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由 Ingo Molnar 提交于
An older binutils bug caused us to not fix up alternatives. This problem involved mutex.c but we dont do lockdep section tricks there anymore, so this workaround is moot. Keep the printk nevertheless, just in case ... We can remove that later on. Signed-off-by: NIngo Molnar <mingo@elte.hu> Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
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由 Andi Kleen 提交于
On VMs implemented using JITs that cache translated code changing the lock prefixes is a quite costly operation that forces the JIT to throw away and retranslate a lot of code. Previously a SMP kernel would rewrite the locks once for each CPU which is quite unnecessary. This patch changes the code to never switch at boot in the normal case (SMP kernel booting with >1 CPU) or only once for SMP kernel on UP. This makes a significant difference in boot up performance on AMD SimNow! Also I expect it to be a little faster on native systems too because a smp switch does a lot of text_poke()s which each synchronize the pipeline. v1->v2: Rename max_cpus v1->v2: Fix off by one in UP check (Thomas Gleixner) Signed-off-by: NAndi Kleen <ak@suse.de> Signed-off-by: NIngo Molnar <mingo@elte.hu> Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
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由 Jeremy Fitzhardinge 提交于
The patch to suppress bitops-related warnings added a pile of ugly casts. Many of these were related to the management of x86 CPU capabilities. Clean these up by adding specific set/clear_cpu_cap macros, and use them consistently. Signed-off-by: NJeremy Fitzhardinge <jeremy@xensource.com> Cc: Andi Kleen <ak@suse.de> Signed-off-by: NIngo Molnar <mingo@elte.hu> Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
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- 20 10月, 2007 1 次提交
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由 Mike Travis 提交于
cpu_data is currently an array defined using NR_CPUS. This means that we overallocate since we will rarely really use maximum configured cpus. When NR_CPU count is raised to 4096 the size of cpu_data becomes 3,145,728 bytes. These changes were adopted from the sparc64 (and ia64) code. An additional field was added to cpuinfo_x86 to be a non-ambiguous cpu index. This corresponds to the index into a cpumask_t as well as the per_cpu index. It's used in various places like show_cpuinfo(). cpu_data is defined to be the boot_cpu_data structure for the NON-SMP case. Signed-off-by: NMike Travis <travis@sgi.com> Acked-by: NChristoph Lameter <clameter@sgi.com> Cc: Andi Kleen <ak@suse.de> Cc: James Bottomley <James.Bottomley@steeleye.com> Cc: Dmitry Torokhov <dtor@mail.ru> Cc: "Antonino A. Daplas" <adaplas@pol.net> Cc: Mark M. Hoffman <mhoffman@lightlink.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NIngo Molnar <mingo@elte.hu> Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
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- 18 10月, 2007 2 次提交
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由 Jan Beulich 提交于
Add support for and use the multi-byte NOPs recently documented to be available on all PentiumPro and later processors. This patch only applies cleanly on top of the "x86: misc. constifications" patch sent earlier. [ tglx: arch/x86 adaptation ] Signed-off-by: NJan Beulich <jbeulich@novell.com> Signed-off-by: NAndi Kleen <ak@suse.de> Signed-off-by: NIngo Molnar <mingo@elte.hu> Signed-off-by: NThomas Gleixner <tglx@linutronix.de> arch/x86/kernel/alternative.c | 23 ++++++++++++++++++++++- include/asm-x86/processor_32.h | 22 ++++++++++++++++++++++ include/asm-x86/processor_64.h | 22 ++++++++++++++++++++++ 3 files changed, 66 insertions(+), 1 deletion(-)
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由 Jan Beulich 提交于
Miscellaneous x86 stuff that can live in .rodata. [ tglx: arch/x86 adaptation ] Signed-off-by: NJan Beulich <jbeulich@novell.com> Signed-off-by: NAndi Kleen <ak@suse.de> Signed-off-by: NIngo Molnar <mingo@elte.hu> Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
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