- 24 9月, 2016 1 次提交
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由 Josh Poimboeuf 提交于
Linus reported the following objtool warning: kernel/signal.o: warning: objtool: .altinstr_replacement+0x54: call without frame pointer save/setup The warning is valid. It's caused by the fact that gcc placed the call instruction in alternative_call_2()'s inline asm before the frame pointer setup, which breaks frame pointer convention and can result in a bad stack trace. Force a stack frame to be created before the call instruction by listing the stack pointer as an output operand in the inline asm statement. Reported-and-tested-by: NLinus Torvalds <torvalds@linux-foundation.org> Signed-off-by: NJosh Poimboeuf <jpoimboe@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20160923214939.j5o7c67nhepzmh3t@trebleSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 29 4月, 2016 2 次提交
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由 Andy Lutomirski 提交于
asm/alternative.h isn't directly useful from assembly, but it shouldn't break the build. Signed-off-by: NAndy Lutomirski <luto@kernel.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/e5b693fcef99fe6e80341c9e97a002fb23871e91.1461698311.git.luto@kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Andy Lutomirski 提交于
alternative.h pulls in ptrace.h, which means that alternatives can't be used in anything referenced from ptrace.h, which is a mess. Break the dependency by pulling text patching helpers into their own header. Signed-off-by: NAndy Lutomirski <luto@kernel.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/99b93b13f2c9eb671f5c98bba4c2cbdc061293a2.1461698311.git.luto@kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 30 1月, 2016 1 次提交
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由 Borislav Petkov 提交于
Move them to a separate header and have the following dependency: x86/cpufeatures.h <- x86/processor.h <- x86/cpufeature.h This makes it easier to use the header in asm code and not include the whole cpufeature.h and add guards for asm. Suggested-by: NH. Peter Anvin <hpa@zytor.com> Signed-off-by: NBorislav Petkov <bp@suse.de> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1453842730-28463-5-git-send-email-bp@alien8.deSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 19 5月, 2015 1 次提交
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由 Ingo Molnar 提交于
We'd like to use xsave_state() earlier, but its SYSTEM_BOOTING check is too imprecise. The real condition that xsave_state() would like to check is whether alternative XSAVE instructions were patched into the kernel image already. Add such a (read-mostly) debug flag and use it in xsave_state(). Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: NIngo Molnar <mingo@kernel.org>
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- 04 4月, 2015 1 次提交
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由 Borislav Petkov 提交于
Quentin caught a corner case with the generation of instruction padding in the ALTERNATIVE_2 macro: if len(orig_insn) < len(alt1) < len(alt2), then not enough padding gets added and that is not good(tm) as we could overwrite the beginning of the next instruction. Luckily, at the time of this writing, we don't have ALTERNATIVE_2() invocations which have that problem and even if we did, a simple fix would be to prepend the instructions with enough prefixes so that that corner case doesn't happen. However, best it would be if we fixed it properly. See below for a simple, abstracted example of what we're doing. So what we ended up doing is, we compute the max(len(alt1), len(alt2)) - len(orig_insn) and feed that value to the .skip gas directive. The max() cannot have conditionals due to gas limitations, thus the fancy integer math. With this patch, all ALTERNATIVE_2 sites get padded correctly; generating obscure test cases pass too: #define alt_max_short(a, b) ((a) ^ (((a) ^ (b)) & -(-((a) < (b))))) #define gen_skip(orig, alt1, alt2, marker) \ .skip -((alt_max_short(alt1, alt2) - (orig)) > 0) * \ (alt_max_short(alt1, alt2) - (orig)),marker .pushsection .text, "ax" .globl main main: gen_skip(1, 2, 4, 0x09) gen_skip(4, 1, 2, 0x10) ... .popsection Thanks to Quentin for catching it and double-checking the fix! Reported-by: NQuentin Casasnovas <quentin.casasnovas@oracle.com> Signed-off-by: NBorislav Petkov <bp@suse.de> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20150404133443.GE21152@pd.tnicSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 23 2月, 2015 1 次提交
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由 Borislav Petkov 提交于
Up until now we have always paid attention to make sure the length of the new instruction replacing the old one is at least less or equal to the length of the old instruction. If the new instruction is longer, at the time it replaces the old instruction it will overwrite the beginning of the next instruction in the kernel image and cause your pants to catch fire. So instead of having to pay attention, teach the alternatives framework to pad shorter old instructions with NOPs at buildtime - but only in the case when len(old instruction(s)) < len(new instruction(s)) and add nothing in the >= case. (In that case we do add_nops() when patching). This way the alternatives user shouldn't have to care about instruction sizes and simply use the macros. Add asm ALTERNATIVE* flavor macros too, while at it. Also, we need to save the pad length in a separate struct alt_instr member for NOP optimization and the way to do that reliably is to carry the pad length instead of trying to detect whether we're looking at single-byte NOPs or at pathological instruction offsets like e9 90 90 90 90, for example, which is a valid instruction. Thanks to Michael Matz for the great help with toolchain questions. Signed-off-by: NBorislav Petkov <bp@suse.de>
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- 30 5月, 2014 1 次提交
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由 Fenghua Yu 提交于
alternative_input_2() replaces old instruction with new instructions with input based on two features. In alternative_input_2(oldinstr, newinstr1, feature1, newinstr2, feature2, input...), feature2 has higher priority to replace oldinstr than feature1. If CPU has feature2, newinstr2 replaces oldinstr and newinstr2 is executed during run time. If CPU doesn't have feature2, but it has feature1, newinstr1 replaces oldinstr and newinstr1 is executed during run time. If CPU doesn't have feature2 and feature1, oldinstr is executed during run time. Signed-off-by: NFenghua Yu <fenghua.yu@intel.com> Link: http://lkml.kernel.org/r/1401387164-43416-5-git-send-email-fenghua.yu@intel.comSigned-off-by: NH. Peter Anvin <hpa@linux.intel.com>
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- 23 7月, 2013 1 次提交
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由 Jiri Kosina 提交于
In fd4363ff ("x86: Introduce int3 (breakpoint)-based instruction patching"), the mechanism that was introduced for notifying alternatives code from int3 exception handler that and exception occured was die_notifier. This is however problematic, as early code might be using jump labels even before the notifier registration has been performed, which will then lead to an oops due to unhandled exception. One of such occurences has been encountered by Fengguang: int3: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC Modules linked in: CPU: 1 PID: 0 Comm: swapper/1 Not tainted 3.11.0-rc1-01429-g04bf576 #8 task: ffff88000da1b040 ti: ffff88000da1c000 task.ti: ffff88000da1c000 RIP: 0010:[<ffffffff811098cc>] [<ffffffff811098cc>] ttwu_do_wakeup+0x28/0x225 RSP: 0000:ffff88000dd03f10 EFLAGS: 00000006 RAX: 0000000000000000 RBX: ffff88000dd12940 RCX: ffffffff81769c40 RDX: 0000000000000002 RSI: 0000000000000000 RDI: 0000000000000001 RBP: ffff88000dd03f28 R08: ffffffff8176a8c0 R09: 0000000000000002 R10: ffffffff810ff484 R11: ffff88000dd129e8 R12: ffff88000dbc90c0 R13: ffff88000dbc90c0 R14: ffff88000da1dfd8 R15: ffff88000da1dfd8 FS: 0000000000000000(0000) GS:ffff88000dd00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b CR2: 00000000ffffffff CR3: 0000000001c88000 CR4: 00000000000006e0 Stack: ffff88000dd12940 ffff88000dbc90c0 ffff88000da1dfd8 ffff88000dd03f48 ffffffff81109e2b ffff88000dd12940 0000000000000000 ffff88000dd03f68 ffffffff81109e9e 0000000000000000 0000000000012940 ffff88000dd03f98 Call Trace: <IRQ> [<ffffffff81109e2b>] ttwu_do_activate.constprop.56+0x6d/0x79 [<ffffffff81109e9e>] sched_ttwu_pending+0x67/0x84 [<ffffffff8110c845>] scheduler_ipi+0x15a/0x2b0 [<ffffffff8104dfb4>] smp_reschedule_interrupt+0x38/0x41 [<ffffffff8173bf5d>] reschedule_interrupt+0x6d/0x80 <EOI> [<ffffffff810ff484>] ? __atomic_notifier_call_chain+0x5/0xc1 [<ffffffff8105cc30>] ? native_safe_halt+0xd/0x16 [<ffffffff81015f10>] default_idle+0x147/0x282 [<ffffffff81017026>] arch_cpu_idle+0x3d/0x5d [<ffffffff81127d6a>] cpu_idle_loop+0x46d/0x5db [<ffffffff81127f5c>] cpu_startup_entry+0x84/0x84 [<ffffffff8104f4f8>] start_secondary+0x3c8/0x3d5 [...] Fix this by directly calling poke_int3_handler() from the int3 exception handler (analogically to what ftrace has been doing already), instead of relying on notifier, registration of which might not have yet been finalized by the time of the first trap. Reported-and-tested-by: NFengguang Wu <fengguang.wu@intel.com> Signed-off-by: NJiri Kosina <jkosina@suse.cz> Acked-by: NMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: H. Peter Anvin <hpa@linux.intel.com> Cc: Fengguang Wu <fengguang.wu@intel.com> Cc: Steven Rostedt <rostedt@goodmis.org> Link: http://lkml.kernel.org/r/alpine.LNX.2.00.1307231007490.14024@pobox.suse.czSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 19 7月, 2013 1 次提交
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由 Masami Hiramatsu 提交于
Since introducing the text_poke_bp() for all text_poke_smp*() callers, text_poke_smp*() are now unused. This patch basically reverts: 3d55cc8a ("x86: Add text_poke_smp for SMP cross modifying code") 7deb18dc ("x86: Introduce text_poke_smp_batch() for batch-code modifying") and related commits. This patch also fixes a Kconfig dependency issue on STOP_MACHINE in the case of CONFIG_SMP && !CONFIG_MODULE_UNLOAD. Signed-off-by: NMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Reviewed-by: NJiri Kosina <jkosina@suse.cz> Cc: H. Peter Anvin <hpa@linux.intel.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Jason Baron <jbaron@akamai.com> Cc: yrl.pp-manager.tt@hitachi.com Cc: Borislav Petkov <bpetkov@suse.de> Link: http://lkml.kernel.org/r/20130718114753.26675.18714.stgit@mhiramat-M0-7522Signed-off-by: NIngo Molnar <mingo@kernel.org>
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- 17 7月, 2013 1 次提交
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由 Jiri Kosina 提交于
Introduce a method for run-time instruction patching on a live SMP kernel based on int3 breakpoint, completely avoiding the need for stop_machine(). The way this is achieved: - add a int3 trap to the address that will be patched - sync cores - update all but the first byte of the patched range - sync cores - replace the first byte (int3) by the first byte of replacing opcode - sync cores According to http://lkml.indiana.edu/hypermail/linux/kernel/1001.1/01530.html synchronization after replacing "all but first" instructions should not be necessary (on Intel hardware), as the syncing after the subsequent patching of the first byte provides enough safety. But there's not only Intel HW out there, and we'd rather be on a safe side. If any CPU instruction execution would collide with the patching, it'd be trapped by the int3 breakpoint and redirected to the provided "handler" (which would typically mean just skipping over the patched region, acting as "nop" has been there, in case we are doing nop -> jump and jump -> nop transitions). Ftrace has been using this very technique since 08d636b6 ("ftrace/x86: Have arch x86_64 use breakpoints instead of stop machine") for ages already, and jump labels are another obvious potential user of this. Based on activities of Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> a few years ago. Reviewed-by: NSteven Rostedt <rostedt@goodmis.org> Reviewed-by: NMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Signed-off-by: NJiri Kosina <jkosina@suse.cz> Link: http://lkml.kernel.org/r/alpine.LNX.2.00.1307121102440.29788@pobox.suse.czSigned-off-by: NH. Peter Anvin <hpa@linux.intel.com>
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- 22 9月, 2012 1 次提交
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由 H. Peter Anvin 提交于
.section/.previous doesn't nest. Use .pushsection/.popsection in <asm/alternative.h> so that they can be properly nested. Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com> Link: http://lkml.kernel.org/r/1348256595-29119-5-git-send-email-hpa@linux.intel.com
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- 23 8月, 2012 1 次提交
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由 Rusty Russell 提交于
We still patch SMP instructions to UP variants if we boot with a single CPU, but not at any other time. In particular, not if we unplug CPUs to return to a single cpu. Paul McKenney points out: mean offline overhead is 6251/48=130.2 milliseconds. If I remove the alternatives_smp_switch() from the offline path [...] the mean offline overhead is 550/42=13.1 milliseconds Basically, we're never going to get those 120ms back, and the code is pretty messy. We get rid of: 1) The "smp-alt-once" boot option. It's actually "smp-alt-boot", the documentation is wrong. It's now the default. 2) The skip_smp_alternatives flag used by suspend. 3) arch_disable_nonboot_cpus_begin() and arch_disable_nonboot_cpus_end() which were only used to set this one flag. Signed-off-by: NRusty Russell <rusty@rustcorp.com.au> Cc: Paul McKenney <paul.mckenney@us.ibm.com> Cc: Suresh Siddha <suresh.b.siddha@intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/87vcgwwive.fsf@rustcorp.com.auSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 30 6月, 2012 1 次提交
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由 Fenghua Yu 提交于
According to Intel 64 and IA-32 SDM and Optimization Reference Manual, beginning with Ivybridge, REG string operation using MOVSB and STOSB can provide both flexible and high-performance REG string operations in cases like memory copy. Enhancement availability is indicated by CPUID.7.0.EBX[9] (Enhanced REP MOVSB/ STOSB). If CPU erms feature is detected, patch copy_user_generic with enhanced fast string version of copy_user_generic. A few new macros are defined to reduce duplicate code in ALTERNATIVE and ALTERNATIVE_2. Signed-off-by: NFenghua Yu <fenghua.yu@intel.com> Link: http://lkml.kernel.org/r/1337908785-14015-1-git-send-email-fenghua.yu@intel.comSigned-off-by: NH. Peter Anvin <hpa@linux.intel.com>
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- 21 1月, 2012 1 次提交
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由 Jan Beulich 提交于
Eric pointed out overly restrictive constraints in atomic64_set(), but there are issues throughout the file. In the cited case, %ebx and %ecx are inputs only (don't get changed by either of the two low level implementations). This was also the case elsewhere. Further in many cases early-clobber indicators were missing. Finally, the previous implementation rolled a custom alternative instruction macro from scratch, rather than using alternative_call() (which was introduced with the commit that the description of the change in question actually refers to). Adjusting has the benefit of not hiding referenced symbols from the compiler, which however requires them to be declared not just in the exporting source file (which, as a desirable side effect, in turn allows that exporting file to become a real 5-line stub). This patch does not eliminate the overly restrictive memory clobbers, however: Doing so would occasionally make the compiler set up a second register for accessing the memory object (to satisfy the added "m" constraint), and it's not clear which of the two non-optimal alternatives is better. v2: Re-do the declaration and exporting of the internal symbols. Reported-by: NEric Dumazet <eric.dumazet@gmail.com> Signed-off-by: NJan Beulich <jbeulich@suse.com> Link: http://lkml.kernel.org/r/4F19A2A5020000780006E0D9@nat28.tlf.novell.com Cc: Luca Barbieri <luca@luca-barbieri.com> Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>
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- 16 9月, 2011 1 次提交
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由 Linus Torvalds 提交于
On x86-64, they were just wasteful: with the explicitly added (now unnecessary) padding, the size of the alternatives structure was 16 bytes, and an alignment of 8 bytes didn't hurt much. However, it was still silly, since the natural size and alignment for the structure is actually just 12 bytes, 4-byte aligned since commit 59e97e4d ("x86: Make alternative instruction pointers relative"). So removing the padding, and removing the extra alignment is just a good idea. On x86-32, the alignment of 4 bytes was correct, but was incorrectly hardcoded as 8 bytes in <asm/alternative-asm.h>. That header file had used to be an x86-64 only header file, but various unification efforts have made it be used for x86-32 too (ie the unification of rwlock and rwsem). That in turn caused x86-32 boot failures, because the extra alignment would result in random zero-filled words in the altinstructions section, causing oopses early at boot when doing alternative instruction replacement. So just remove all the alignment noise entirely. It's wrong, and it's unnecessary. The section itself is already properly aligned by the linker scripts, and all additions to the section had better be of the proper 12-byte format, keeping it aligned. So if the align directive were to ever make a difference, that would be an indication of a serious bug to begin with. Reported-by: NWerner Landgraf <w.landgraf@ru.r> Acked-by: NAndrew Lutomirski <luto@mit.edu> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 14 7月, 2011 1 次提交
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由 Andy Lutomirski 提交于
This save a few bytes on x86-64 and means that future patches can apply alternatives to unrelocated code. Signed-off-by: NAndy Lutomirski <luto@mit.edu> Link: http://lkml.kernel.org/r/ff64a6b9a1a3860ca4a7b8b6dc7b4754f9491cd7.1310563276.git.luto@mit.eduSigned-off-by: NH. Peter Anvin <hpa@linux.intel.com>
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- 19 4月, 2011 1 次提交
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由 H. Peter Anvin 提交于
Clean up and unify the NOP selection infrastructure: - Make the atomic 5-byte NOP a part of the selection system. - Pick NOPs once during early boot and then be done with it. Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com> Cc: Tejun Heo <tj@kernel.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jason Baron <jbaron@redhat.com> Link: http://lkml.kernel.org/r/1303166160-10315-3-git-send-email-hpa@linux.intel.com
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- 05 4月, 2011 1 次提交
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由 Jason Baron 提交于
Introduce: static __always_inline bool static_branch(struct jump_label_key *key); instead of the old JUMP_LABEL(key, label) macro. In this way, jump labels become really easy to use: Define: struct jump_label_key jump_key; Can be used as: if (static_branch(&jump_key)) do unlikely code enable/disale via: jump_label_inc(&jump_key); jump_label_dec(&jump_key); that's it! For the jump labels disabled case, the static_branch() becomes an atomic_read(), and jump_label_inc()/dec() are simply atomic_inc(), atomic_dec() operations. We show testing results for this change below. Thanks to H. Peter Anvin for suggesting the 'static_branch()' construct. Since we now require a 'struct jump_label_key *key', we can store a pointer into the jump table addresses. In this way, we can enable/disable jump labels, in basically constant time. This change allows us to completely remove the previous hashtable scheme. Thanks to Peter Zijlstra for this re-write. Testing: I ran a series of 'tbench 20' runs 5 times (with reboots) for 3 configurations, where tracepoints were disabled. jump label configured in avg: 815.6 jump label *not* configured in (using atomic reads) avg: 800.1 jump label *not* configured in (regular reads) avg: 803.4 Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <20110316212947.GA8792@redhat.com> Signed-off-by: NJason Baron <jbaron@redhat.com> Suggested-by: NH. Peter Anvin <hpa@linux.intel.com> Tested-by: NDavid Daney <ddaney@caviumnetworks.com> Acked-by: NRalf Baechle <ralf@linux-mips.org> Acked-by: NDavid S. Miller <davem@davemloft.net> Acked-by: NMathieu Desnoyers <mathieu.desnoyers@efficios.com> Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
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- 14 12月, 2010 1 次提交
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由 Suresh Siddha 提交于
During suspend, we disable all the non boot cpus. And during resume we bring them all back again. So no need to do alternatives_smp_switch() in between. On my core 2 based laptop, this speeds up the suspend path by 15msec and the resume path by 5 msec (suspend/resume speed up differences can be attributed to the different P-states that the cpu is in during suspend/resume). Signed-off-by: NSuresh Siddha <suresh.b.siddha@intel.com> LKML-Reference: <1290557500.4946.8.camel@sbsiddha-MOBL3.sc.intel.com> Cc: Rafael J. Wysocki <rjw@sisk.pl> Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>
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- 07 12月, 2010 1 次提交
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由 Masami Hiramatsu 提交于
Introduce text_poke_smp_batch(). This function modifies several text areas with one stop_machine() on SMP. Because calling stop_machine() is heavy task, it is better to aggregate text_poke requests. ( Note: I've talked with Rusty about this interface, and he would not like to expand stop_machine() interface, since it is not for generic use. ) Signed-off-by: NMasami Hiramatsu <mhiramat@redhat.com> Acked-by: NSteven Rostedt <rostedt@goodmis.org> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Jason Baron <jbaron@redhat.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Jan Beulich <jbeulich@novell.com> Cc: 2nddept-manager@sdl.hitachi.co.jp LKML-Reference: <20101203095422.2961.51217.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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- 08 7月, 2010 1 次提交
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由 H. Peter Anvin 提交于
We already have cpufeature indicies above 255, so use a 16-bit number for the alternatives index. This consumes a padding field and so doesn't add any size, but it means that abusing the padding field to create assembly errors on overflow no longer works. We can retain the test simply by redirecting it to the .discard section, however. [ v3: updated to include open-coded locations ] Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com> LKML-Reference: <tip-f88731e3068f9d1392ba71cc9f50f035d26a0d4f@git.kernel.org> Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
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- 30 4月, 2010 1 次提交
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由 H. Peter Anvin 提交于
Checkin b3ac891b: x86: Add support for lock prefix in alternatives ... did not define LOCK_PREFIX_HERE in the case of a uniprocessor build. As a result, it would cause any of the usages of this macro to fail on a uniprocessor build. Fix this by defining LOCK_PREFIX_HERE as a null string. Signed-off-by: NH. Peter Anvin <hpa@zytor.com> Cc: Luca Barbieri <luca@luca-barbieri.com> LKML-Reference: <1267005265-27958-2-git-send-email-luca@luca-barbieri.com>
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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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- 07 4月, 2010 1 次提交
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由 Borislav Petkov 提交于
Add support for the hardware version of the Hamming weight function, popcnt, present in CPUs which advertize it under CPUID, Function 0x0000_0001_ECX[23]. On CPUs which don't support it, we fallback to the default lib/hweight.c sw versions. A synthetic benchmark comparing popcnt with __sw_hweight64 showed almost a 3x speedup on a F10h machine. Signed-off-by: NBorislav Petkov <borislav.petkov@amd.com> LKML-Reference: <20100318112015.GC11152@aftab> Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
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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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- 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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- 02 12月, 2009 1 次提交
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由 Jan Beulich 提交于
Having run into the run-(boot-)time check a couple of times lately, I finally took time to find a build-time check so that one doesn't need to analyze the register/stack dump and resolve this (through manual lookup in vmlinux) to the offending construct. The assembler will emit a message like "Error: value of <num> too large for field of 1 bytes at <offset>", which while not pointing out the source location still makes analysis quite a bit easier. Signed-off-by: NJan Beulich <jbeulich@novell.com> LKML-Reference: <4B0FF8AA0200007800022703@vpn.id2.novell.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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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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- 28 4月, 2009 1 次提交
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由 Mathieu Desnoyers 提交于
Alternative header duplicates assembly that could be merged in one single macro. Merging this into this macro also allows to directly declare ALTERNATIVE() statements within assembly code. Uses a __stringify() of the feature bits rather than passing a "i" operand. Leave the old %0 operand as-is (set to 0), unused to stay compatible with API. (v2: tab alignment fixes) [ Impact: cleanup ] Signed-off-by: NMathieu Desnoyers <mathieu.desnoyers@polymtl.ca> LKML-Reference: <20090428151346.GA31212@Krystal> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 23 10月, 2008 2 次提交
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由 H. Peter Anvin 提交于
Change header guards named "ASM_X86__*" to "_ASM_X86_*" since: a. the double underscore is ugly and pointless. b. no leading underscore violates namespace constraints. Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
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由 Al Viro 提交于
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk> Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
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- 23 7月, 2008 1 次提交
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由 Vegard Nossum 提交于
This patch is the result of an automatic script that consolidates the format of all the headers in include/asm-x86/. The format: 1. No leading underscore. Names with leading underscores are reserved. 2. Pathname components are separated by two underscores. So we can distinguish between mm_types.h and mm/types.h. 3. Everything except letters and numbers are turned into single underscores. Signed-off-by: NVegard Nossum <vegard.nossum@gmail.com>
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- 24 5月, 2008 1 次提交
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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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- 17 4月, 2008 1 次提交
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由 Joe Perches 提交于
Signed-off-by: NJoe Perches <joe@perches.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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