summaryrefslogtreecommitdiff
path: root/arch/x86
AgeCommit message (Collapse)Author
2012-03-12perf/x86: Fix local vs remote memory events for NHM/WSMPeter Zijlstra
Verified using the below proglet.. before: [root@westmere ~]# perf stat -e node-stores -e node-store-misses ./numa 0 remote write Performance counter stats for './numa 0': 2,101,554 node-stores 2,096,931 node-store-misses 5.021546079 seconds time elapsed [root@westmere ~]# perf stat -e node-stores -e node-store-misses ./numa 1 local write Performance counter stats for './numa 1': 501,137 node-stores 199 node-store-misses 5.124451068 seconds time elapsed After: [root@westmere ~]# perf stat -e node-stores -e node-store-misses ./numa 0 remote write Performance counter stats for './numa 0': 2,107,516 node-stores 2,097,187 node-store-misses 5.012755149 seconds time elapsed [root@westmere ~]# perf stat -e node-stores -e node-store-misses ./numa 1 local write Performance counter stats for './numa 1': 2,063,355 node-stores 165 node-store-misses 5.082091494 seconds time elapsed #define _GNU_SOURCE #include <sched.h> #include <stdio.h> #include <errno.h> #include <sys/mman.h> #include <sys/types.h> #include <dirent.h> #include <signal.h> #include <unistd.h> #include <numaif.h> #include <stdlib.h> #define SIZE (32*1024*1024) volatile int done; void sig_done(int sig) { done = 1; } int main(int argc, char **argv) { cpu_set_t *mask, *mask2; size_t size; int i, err, t; int nrcpus = 1024; char *mem; unsigned long nodemask = 0x01; /* node 0 */ DIR *node; struct dirent *de; int read = 0; int local = 0; if (argc < 2) { printf("usage: %s [0-3]\n", argv[0]); printf(" bit0 - local/remote\n"); printf(" bit1 - read/write\n"); exit(0); } switch (atoi(argv[1])) { case 0: printf("remote write\n"); break; case 1: printf("local write\n"); local = 1; break; case 2: printf("remote read\n"); read = 1; break; case 3: printf("local read\n"); local = 1; read = 1; break; } mask = CPU_ALLOC(nrcpus); size = CPU_ALLOC_SIZE(nrcpus); CPU_ZERO_S(size, mask); node = opendir("/sys/devices/system/node/node0/"); if (!node) perror("opendir"); while ((de = readdir(node))) { int cpu; if (sscanf(de->d_name, "cpu%d", &cpu) == 1) CPU_SET_S(cpu, size, mask); } closedir(node); mask2 = CPU_ALLOC(nrcpus); CPU_ZERO_S(size, mask2); for (i = 0; i < size; i++) CPU_SET_S(i, size, mask2); CPU_XOR_S(size, mask2, mask2, mask); // invert if (!local) mask = mask2; err = sched_setaffinity(0, size, mask); if (err) perror("sched_setaffinity"); mem = mmap(0, SIZE, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); err = mbind(mem, SIZE, MPOL_BIND, &nodemask, 8*sizeof(nodemask), MPOL_MF_MOVE); if (err) perror("mbind"); signal(SIGALRM, sig_done); alarm(5); if (!read) { while (!done) { for (i = 0; i < SIZE; i++) mem[i] = 0x01; } } else { while (!done) { for (i = 0; i < SIZE; i++) t += *(volatile char *)(mem + i); } } return 0; } Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Stephane Eranian <eranian@google.com> Cc: <stable@kernel.org> Link: http://lkml.kernel.org/n/tip-tq73sxus35xmqpojf7ootxgs@git.kernel.org Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-03-09x86: Derandom delay_tsc for 64 bitThomas Gleixner
Commit f0fbf0abc093 ("x86: integrate delay functions") converted delay_tsc() into a random delay generator for 64 bit. The reason is that it merged the mostly identical versions of delay_32.c and delay_64.c. Though the subtle difference of the result was: static void delay_tsc(unsigned long loops) { - unsigned bclock, now; + unsigned long bclock, now; Now the function uses rdtscl() which returns the lower 32bit of the TSC. On 32bit that's not problematic as unsigned long is 32bit. On 64 bit this fails when the lower 32bit are close to wrap around when bclock is read, because the following check if ((now - bclock) >= loops) break; evaluated to true on 64bit for e.g. bclock = 0xffffffff and now = 0 because the unsigned long (now - bclock) of these values results in 0xffffffff00000001 which is definitely larger than the loops value. That explains Tvortkos observation: "Because I am seeing udelay(500) (_occasionally_) being short, and that by delaying for some duration between 0us (yep) and 491us." Make those variables explicitely u32 again, so this works for both 32 and 64 bit. Reported-by: Tvrtko Ursulin <tvrtko.ursulin@onelan.co.uk> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: stable@vger.kernel.org # >= 2.6.27 Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-06x86: fix typo in recent find_vma_prev purgeLinus Torvalds
It turns out that test-compiling this file on x86-64 doesn't really help, because much of it is x86-32-specific. And so I hadn't noticed the slightly over-eager removal of the 'r' from 'addr' variable despite thinking I had tested it. Signed-off-by: Linus "oopsie" Torvalds <torvalds@linux-foundation.org>
2012-03-06vm: avoid using find_vma_prev() unnecessarilyLinus Torvalds
Several users of "find_vma_prev()" were not in fact interested in the previous vma if there was no primary vma to be found either. And in those cases, we're much better off just using the regular "find_vma()", and then "prev" can be looked up by just checking vma->vm_prev. The find_vma_prev() semantics are fairly subtle (see Mikulas' recent commit 83cd904d271b: "mm: fix find_vma_prev"), and the whole "return prev by reference" means that it generates worse code too. Thus this "let's avoid using this inconvenient and clearly too subtle interface when we don't really have to" patch. Cc: Mikulas Patocka <mpatocka@redhat.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-05Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes/pci Pull PCI fixes from Jesse Barnes: "A couple of fixes for booting specific machines, and one for a minor memory leak on pre-_CRS platforms." * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes/pci: x86/PCI: do not tie MSI MS-7253 use_crs quirk to BIOS version x86/PCI: use host bridge _CRS info on MSI MS-7253 PCI: fix memleak when ACPI _CRS is not used.
2012-03-05aout: move setup_arg_pages() prior to reading/mapping the binaryAl Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-02perf/x86/kvm: Fix Host-Only/Guest-Only counting with SVM disabledJoerg Roedel
It turned out that a performance counter on AMD does not count at all when the GO or HO bit is set in the control register and SVM is disabled in EFER. This patch works around this issue by masking out the HO bit in the performance counter control register when SVM is not enabled. The GO bit is not touched because it is only set when the user wants to count in guest-mode only. So when SVM is disabled the counter should not run at all and the not-counting is the intended behaviour. Signed-off-by: Joerg Roedel <joerg.roedel@amd.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Avi Kivity <avi@redhat.com> Cc: Stephane Eranian <eranian@google.com> Cc: David Ahern <dsahern@gmail.com> Cc: Gleb Natapov <gleb@redhat.com> Cc: Robert Richter <robert.richter@amd.com> Cc: stable@vger.kernel.org # v3.2 Link: http://lkml.kernel.org/r/1330523852-19566-1-git-send-email-joerg.roedel@amd.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-03-01x86/PCI: do not tie MSI MS-7253 use_crs quirk to BIOS versionJonathan Nieder
Carlos was getting WARNING: at drivers/pci/pci.c:118 pci_ioremap_bar+0x24/0x52() when probing his sound card, and sound did not work. After adding pci=use_crs to the kernel command line, no more trouble. Ok, we can add a quirk. dmidecode output reveals that this is an MSI MS-7253, for which we already have a quirk, but the short-sighted author tied the quirk to a single BIOS version, making it not kick in on Carlos's machine with BIOS V1.2. If a later BIOS update makes it no longer necessary to look at the _CRS info it will still be harmless, so let's stop trying to guess which versions have and don't have accurate _CRS tables. Addresses https://bugtrack.alsa-project.org/alsa-bug/view.php?id=5533 Also see <https://bugzilla.kernel.org/show_bug.cgi?id=42619>. Reported-by: Carlos Luna <caralu74@gmail.com> Reviewed-by: Bjorn Helgaas <bhelgaas@google.com> Signed-off-by: Jonathan Nieder <jrnieder@gmail.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2012-02-28x86/PCI: use host bridge _CRS info on MSI MS-7253Jonathan Nieder
In the spirit of commit 29cf7a30f8a0 ("x86/PCI: use host bridge _CRS info on ASUS M2V-MX SE"), this DMI quirk turns on "pci_use_crs" by default on a board that needs it. This fixes boot failures and oopses introduced in 3e3da00c01d0 ("x86/pci: AMD one chain system to use pci read out res"). The quirk is quite targetted (to a specific board and BIOS version) for two reasons: (1) to emphasize that this method of tackling the problem one quirk at a time is a little insane (2) to give BIOS vendors an opportunity to use simpler tables and allow us to return to generic behavior (whatever that happens to be) with a later BIOS update In other words, I am not at all happy with having quirks like this. But it is even worse for the kernel not to work out of the box on these machines, so... Reference: https://bugzilla.kernel.org/show_bug.cgi?id=42619 Reported-by: Svante Signell <svante.signell@telia.com> Signed-off-by: Jonathan Nieder <jrnieder@gmail.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2012-02-27Merge branch 'x86-urgent-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip * 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/mce/AMD: Fix UP build error x86: Specify a size for the cmp in the NMI handler x86/nmi: Test saved %cs in NMI to determine nested NMI case x86/amd: Fix L1i and L2 cache sharing information for AMD family 15h processors x86/microcode: Remove noisy AMD microcode warning
2012-02-26Merge tag 'stable/for-linus-fixes-3.3-rc5' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen Two fixes to fix a memory corruption bug when WC pages never get converted back to WB but end up being recycled in the general memory pool as WC. There is a better way of fixing this, but there is not enough time to do the full benchmarking to pick one of the right options - so picking the one that favors stability for right now. Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> * tag 'stable/for-linus-fixes-3.3-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen: xen/pat: Disable PAT support for now. xen/setup: Remove redundant filtering of PTE masks.
2012-02-23PCI: fix memleak when ACPI _CRS is not used.Yinghai Lu
warning: unreferenced object 0xffff8801f6914200 (size 512): comm "swapper/0", pid 1, jiffies 4294893643 (age 2664.644s) hex dump (first 32 bytes): 00 00 c0 fe 00 00 00 00 ff ff ff ff 00 00 00 00 ................ 60 58 2f f6 03 88 ff ff 00 02 00 00 00 00 00 00 `X/............. backtrace: [<ffffffff81c2408c>] kmemleak_alloc+0x26/0x43 [<ffffffff8113764f>] __kmalloc+0x121/0x183 [<ffffffff81ca8d93>] get_current_resources+0x5a/0xc6 [<ffffffff81c5bedd>] pci_acpi_scan_root+0x13c/0x21c [<ffffffff81c2a745>] acpi_pci_root_add+0x1e1/0x421 [<ffffffff81408f50>] acpi_device_probe+0x50/0x190 [<ffffffff8149edc7>] really_probe+0x99/0x126 [<ffffffff8149ef83>] driver_probe_device+0x3b/0x56 [<ffffffff8149effd>] __driver_attach+0x5f/0x82 [<ffffffff8149d860>] bus_for_each_dev+0x5c/0x88 [<ffffffff8149eb87>] driver_attach+0x1e/0x20 [<ffffffff8149e7cc>] bus_add_driver+0xca/0x21d [<ffffffff8149f47b>] driver_register+0x91/0xfe [<ffffffff81409d09>] acpi_bus_register_driver+0x43/0x45 [<ffffffff8278bdc9>] acpi_pci_root_init+0x20/0x28 [<ffffffff810001e7>] do_one_initcall+0x57/0x134 The system has _CRS for root buses, but they are not used because the machine date is before the cutoff date for _CRS usage. Try to free those unused resource arrays and names. Reviewed-by: Bjorn Helgaas <bhelgaas@google.com> Signed-off-by: Yinghai Lu <yinghai@kernel.org> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2012-02-22x86/mce/AMD: Fix UP build errorBorislav Petkov
141168c36cde ("x86: Simplify code by removing a !SMP #ifdefs from 'struct cpuinfo_x86'") removed a bunch of CONFIG_SMP ifdefs around code touching struct cpuinfo_x86 members but also caused the following build error with Randy's randconfigs: mce_amd.c:(.cpuinit.text+0x4723): undefined reference to `cpu_llc_shared_map' Restore the #ifdef in threshold_create_bank() which creates symlinks on the non-BSP CPUs. There's a better patch series being worked on by Kevin Winchester which will solve this in a cleaner fashion, but that series is too ambitious for v3.3 merging - so we first queue up this trivial fix and then do the rest for v3.4. Signed-off-by: Borislav Petkov <bp@alien8.de> Acked-by: Kevin Winchester <kjwinchester@gmail.com> Cc: Randy Dunlap <rdunlap@xenotime.net> Cc: Nick Bowler <nbowler@elliptictech.com> Link: http://lkml.kernel.org/r/20120203191801.GA2846@x1.osrc.amd.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-02-20i387: export 'fpu_owner_task' per-cpu variableLinus Torvalds
(And define it properly for x86-32, which had its 'current_task' declaration in separate from x86-64) Bitten by my dislike for modules on the machines I use, and the fact that apparently nobody else actually wanted to test the patches I sent out. Snif. Nobody else cares. Anyway, we probably should uninline the 'kernel_fpu_begin()' function that is what modules actually use and that references this, but this is the minimal fix for now. Reported-by: Josh Boyer <jwboyer@gmail.com> Reported-and-tested-by: Jongman Heo <jongman.heo@samsung.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-02-20x86: Specify a size for the cmp in the NMI handlerSteven Rostedt
Linus noticed that the cmp used to check if the code segment is __KERNEL_CS or not did not specify a size. Perhaps it does not matter as H. Peter Anvin noted that user space can not set the bottom two bits of the %cs register. But it's best not to let the assembly choose and change things between different versions of gas, but instead just pick the size. Four bytes are used to compare the saved code segment against __KERNEL_CS. Perhaps this might mess up Xen, but we can fix that when the time comes. Also I noticed that there was another non-specified cmp that checks the special stack variable if it is 1 or 0. This too probably doesn't matter what cmp is used, but this patch uses cmpl just to make it non ambiguous. Link: http://lkml.kernel.org/r/CA+55aFxfAn9MWRgS3O5k2tqN5ys1XrhSFVO5_9ZAoZKDVgNfGA@mail.gmail.com Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2012-02-20i387: support lazy restore of FPU stateLinus Torvalds
This makes us recognize when we try to restore FPU state that matches what we already have in the FPU on this CPU, and avoids the restore entirely if so. To do this, we add two new data fields: - a percpu 'fpu_owner_task' variable that gets written any time we update the "has_fpu" field, and thus acts as a kind of back-pointer to the task that owns the CPU. The exception is when we save the FPU state as part of a context switch - if the save can keep the FPU state around, we leave the 'fpu_owner_task' variable pointing at the task whose FP state still remains on the CPU. - a per-thread 'last_cpu' field, that indicates which CPU that thread used its FPU on last. We update this on every context switch (writing an invalid CPU number if the last context switch didn't leave the FPU in a lazily usable state), so we know that *that* thread has done nothing else with the FPU since. These two fields together can be used when next switching back to the task to see if the CPU still matches: if 'fpu_owner_task' matches the task we are switching to, we know that no other task (or kernel FPU usage) touched the FPU on this CPU in the meantime, and if the current CPU number matches the 'last_cpu' field, we know that this thread did no other FP work on any other CPU, so the FPU state on the CPU must match what was saved on last context switch. In that case, we can avoid the 'f[x]rstor' entirely, and just clear the CR0.TS bit. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-02-20i387: use 'restore_fpu_checking()' directly in task switching codeLinus Torvalds
This inlines what is usually just a couple of instructions, but more importantly it also fixes the theoretical error case (can that FPU restore really ever fail? Maybe we should remove the checking). We can't start sending signals from within the scheduler, we're much too deep in the kernel and are holding the runqueue lock etc. So don't bother even trying. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-02-20i387: fix up some fpu_counter confusionLinus Torvalds
This makes sure we clear the FPU usage counter for newly created tasks, just so that we start off in a known state (for example, don't try to preload the FPU state on the first task switch etc). It also fixes a thinko in when we increment the fpu_counter at task switch time, introduced by commit 34ddc81a230b ("i387: re-introduce FPU state preloading at context switch time"). We should increment the *new* task fpu_counter, not the old task, and only if we decide to use that state (whether lazily or preloaded). Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-02-20xen/pat: Disable PAT support for now.Konrad Rzeszutek Wilk
[Pls also look at https://lkml.org/lkml/2012/2/10/228] Using of PAT to change pages from WB to WC works quite nicely. Changing it back to WB - not so much. The crux of the matter is that the code that does this (__page_change_att_set_clr) has only limited information so when it tries to the change it gets the "raw" unfiltered information instead of the properly filtered one - and the "raw" one tell it that PSE bit is on (while infact it is not). As a result when the PTE is set to be WB from WC, we get tons of: :WARNING: at arch/x86/xen/mmu.c:475 xen_make_pte+0x67/0xa0() :Hardware name: HP xw4400 Workstation .. snip.. :Pid: 27, comm: kswapd0 Tainted: G W 3.2.2-1.fc16.x86_64 #1 :Call Trace: : [<ffffffff8106dd1f>] warn_slowpath_common+0x7f/0xc0 : [<ffffffff8106dd7a>] warn_slowpath_null+0x1a/0x20 : [<ffffffff81005a17>] xen_make_pte+0x67/0xa0 : [<ffffffff810051bd>] __raw_callee_save_xen_make_pte+0x11/0x1e : [<ffffffff81040e15>] ? __change_page_attr_set_clr+0x9d5/0xc00 : [<ffffffff8114c2e8>] ? __purge_vmap_area_lazy+0x158/0x1d0 : [<ffffffff8114cca5>] ? vm_unmap_aliases+0x175/0x190 : [<ffffffff81041168>] change_page_attr_set_clr+0x128/0x4c0 : [<ffffffff81041542>] set_pages_array_wb+0x42/0xa0 : [<ffffffff8100a9b2>] ? check_events+0x12/0x20 : [<ffffffffa0074d4c>] ttm_pages_put+0x1c/0x70 [ttm] : [<ffffffffa0074e98>] ttm_page_pool_free+0xf8/0x180 [ttm] : [<ffffffffa0074f78>] ttm_pool_mm_shrink+0x58/0x90 [ttm] : [<ffffffff8112ba04>] shrink_slab+0x154/0x310 : [<ffffffff8112f17a>] balance_pgdat+0x4fa/0x6c0 : [<ffffffff8112f4b8>] kswapd+0x178/0x3d0 : [<ffffffff815df134>] ? __schedule+0x3d4/0x8c0 : [<ffffffff81090410>] ? remove_wait_queue+0x50/0x50 : [<ffffffff8112f340>] ? balance_pgdat+0x6c0/0x6c0 : [<ffffffff8108fb6c>] kthread+0x8c/0xa0 for every page. The proper fix for this is has been posted and is https://lkml.org/lkml/2012/2/10/228 "x86/cpa: Use pte_attrs instead of pte_flags on CPA/set_p.._wb/wc operations." along with a detailed description of the problem and solution. But since that posting has gone nowhere I am proposing this band-aid solution so that at least users don't get the page corruption (the pages that are WC don't get changed to WB and end up being recycled for filesystem or other things causing mysterious crashes). The negative impact of this patch is that users of WC flag (which are InfiniBand, radeon, nouveau drivers) won't be able to set that flag - so they are going to see performance degradation. But stability is more important here. Fixes RH BZ# 742032, 787403, and 745574 Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2012-02-20xen/setup: Remove redundant filtering of PTE masks.Konrad Rzeszutek Wilk
commit 7347b4082e55ac4a673f06a0a0ce25c37273c9ec "xen: Allow unprivileged Xen domains to create iomap pages" added a redundant line in the early bootup code to filter out the PTE. That filtering is already done a bit earlier so this extra processing is not required. Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2012-02-20x86/nmi: Test saved %cs in NMI to determine nested NMI caseSteven Rostedt
Currently, the NMI handler tests if it is nested by checking the special variable saved on the stack (set during NMI handling) and whether the saved stack is the NMI stack as well (to prevent the race when the variable is set to zero). But userspace may set their %rsp to any value as long as they do not derefence it, and it may make it point to the NMI stack, which will prevent NMIs from triggering while the userspace app is running. (I tested this, and it is indeed the case) Add another check to determine nested NMIs by looking at the saved %cs (code segment register) and making sure that it is the kernel code segment. Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: <stable@kernel.org> Link: http://lkml.kernel.org/r/1329687817.1561.27.camel@acer.local.home Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-02-18i387: re-introduce FPU state preloading at context switch timeLinus Torvalds
After all the FPU state cleanups and finally finding the problem that caused all our FPU save/restore problems, this re-introduces the preloading of FPU state that was removed in commit b3b0870ef3ff ("i387: do not preload FPU state at task switch time"). However, instead of simply reverting the removal, this reimplements preloading with several fixes, most notably - properly abstracted as a true FPU state switch, rather than as open-coded save and restore with various hacks. In particular, implementing it as a proper FPU state switch allows us to optimize the CR0.TS flag accesses: there is no reason to set the TS bit only to then almost immediately clear it again. CR0 accesses are quite slow and expensive, don't flip the bit back and forth for no good reason. - Make sure that the same model works for both x86-32 and x86-64, so that there are no gratuitous differences between the two due to the way they save and restore segment state differently due to architectural differences that really don't matter to the FPU state. - Avoid exposing the "preload" state to the context switch routines, and in particular allow the concept of lazy state restore: if nothing else has used the FPU in the meantime, and the process is still on the same CPU, we can avoid restoring state from memory entirely, just re-expose the state that is still in the FPU unit. That optimized lazy restore isn't actually implemented here, but the infrastructure is set up for it. Of course, older CPU's that use 'fnsave' to save the state cannot take advantage of this, since the state saving also trashes the state. In other words, there is now an actual _design_ to the FPU state saving, rather than just random historical baggage. Hopefully it's easier to follow as a result. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-02-18i387: move TS_USEDFPU flag from thread_info to task_structLinus Torvalds
This moves the bit that indicates whether a thread has ownership of the FPU from the TS_USEDFPU bit in thread_info->status to a word of its own (called 'has_fpu') in task_struct->thread.has_fpu. This fixes two independent bugs at the same time: - changing 'thread_info->status' from the scheduler causes nasty problems for the other users of that variable, since it is defined to be thread-synchronous (that's what the "TS_" part of the naming was supposed to indicate). So perfectly valid code could (and did) do ti->status |= TS_RESTORE_SIGMASK; and the compiler was free to do that as separate load, or and store instructions. Which can cause problems with preemption, since a task switch could happen in between, and change the TS_USEDFPU bit. The change to TS_USEDFPU would be overwritten by the final store. In practice, this seldom happened, though, because the 'status' field was seldom used more than once, so gcc would generally tend to generate code that used a read-modify-write instruction and thus happened to avoid this problem - RMW instructions are naturally low fat and preemption-safe. - On x86-32, the current_thread_info() pointer would, during interrupts and softirqs, point to a *copy* of the real thread_info, because x86-32 uses %esp to calculate the thread_info address, and thus the separate irq (and softirq) stacks would cause these kinds of odd thread_info copy aliases. This is normally not a problem, since interrupts aren't supposed to look at thread information anyway (what thread is running at interrupt time really isn't very well-defined), but it confused the heck out of irq_fpu_usable() and the code that tried to squirrel away the FPU state. (It also caused untold confusion for us poor kernel developers). It also turns out that using 'task_struct' is actually much more natural for most of the call sites that care about the FPU state, since they tend to work with the task struct for other reasons anyway (ie scheduling). And the FPU data that we are going to save/restore is found there too. Thanks to Arjan Van De Ven <arjan@linux.intel.com> for pointing us to the %esp issue. Cc: Arjan van de Ven <arjan@linux.intel.com> Reported-and-tested-by: Raphael Prevost <raphael@buro.asia> Acked-and-tested-by: Suresh Siddha <suresh.b.siddha@intel.com> Tested-by: Peter Anvin <hpa@zytor.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-02-16i387: move AMD K7/K8 fpu fxsave/fxrstor workaround from save to restoreLinus Torvalds
The AMD K7/K8 CPUs don't save/restore FDP/FIP/FOP unless an exception is pending. In order to not leak FIP state from one process to another, we need to do a floating point load after the fxsave of the old process, and before the fxrstor of the new FPU state. That resets the state to the (uninteresting) kernel load, rather than some potentially sensitive user information. We used to do this directly after the FPU state save, but that is actually very inconvenient, since it (a) corrupts what is potentially perfectly good FPU state that we might want to lazy avoid restoring later and (b) on x86-64 it resulted in a very annoying ordering constraint, where "__unlazy_fpu()" in the task switch needs to be delayed until after the DS segment has been reloaded just to get the new DS value. Coupling it to the fxrstor instead of the fxsave automatically avoids both of these issues, and also ensures that we only do it when actually necessary (the FP state after a save may never actually get used). It's simply a much more natural place for the leaked state cleanup. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-02-16i387: do not preload FPU state at task switch timeLinus Torvalds
Yes, taking the trap to re-load the FPU/MMX state is expensive, but so is spending several days looking for a bug in the state save/restore code. And the preload code has some rather subtle interactions with both paravirtualization support and segment state restore, so it's not nearly as simple as it should be. Also, now that we no longer necessarily depend on a single bit (ie TS_USEDFPU) for keeping track of the state of the FPU, we migth be able to do better. If we are really switching between two processes that keep touching the FP state, save/restore is inevitable, but in the case of having one process that does most of the FPU usage, we may actually be able to do much better than the preloading. In particular, we may be able to keep track of which CPU the process ran on last, and also per CPU keep track of which process' FP state that CPU has. For modern CPU's that don't destroy the FPU contents on save time, that would allow us to do a lazy restore by just re-enabling the existing FPU state - with no restore cost at all! Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-02-16i387: don't ever touch TS_USEDFPU directly, use helper functionsLinus Torvalds
This creates three helper functions that do the TS_USEDFPU accesses, and makes everybody that used to do it by hand use those helpers instead. In addition, there's a couple of helper functions for the "change both CR0.TS and TS_USEDFPU at the same time" case, and the places that do that together have been changed to use those. That means that we have fewer random places that open-code this situation. The intent is partly to clarify the code without actually changing any semantics yet (since we clearly still have some hard to reproduce bug in this area), but also to make it much easier to use another approach entirely to caching the CR0.TS bit for software accesses. Right now we use a bit in the thread-info 'status' variable (this patch does not change that), but we might want to make it a full field of its own or even make it a per-cpu variable. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-02-16i387: move TS_USEDFPU clearing out of __save_init_fpu and into callersLinus Torvalds
Touching TS_USEDFPU without touching CR0.TS is confusing, so don't do it. By moving it into the callers, we always do the TS_USEDFPU next to the CR0.TS accesses in the source code, and it's much easier to see how the two go hand in hand. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-02-16i387: fix x86-64 preemption-unsafe user stack save/restoreLinus Torvalds
Commit 5b1cbac37798 ("i387: make irq_fpu_usable() tests more robust") added a sanity check to the #NM handler to verify that we never cause the "Device Not Available" exception in kernel mode. However, that check actually pinpointed a (fundamental) race where we do cause that exception as part of the signal stack FPU state save/restore code. Because we use the floating point instructions themselves to save and restore state directly from user mode, we cannot do that atomically with testing the TS_USEDFPU bit: the user mode access itself may cause a page fault, which causes a task switch, which saves and restores the FP/MMX state from the kernel buffers. This kind of "recursive" FP state save is fine per se, but it means that when the signal stack save/restore gets restarted, it will now take the '#NM' exception we originally tried to avoid. With preemption this can happen even without the page fault - but because of the user access, we cannot just disable preemption around the save/restore instruction. There are various ways to solve this, including using the "enable/disable_page_fault()" helpers to not allow page faults at all during the sequence, and fall back to copying things by hand without the use of the native FP state save/restore instructions. However, the simplest thing to do is to just allow the #NM from kernel space, but fix the race in setting and clearing CR0.TS that this all exposed: the TS bit changes and the TS_USEDFPU bit absolutely have to be atomic wrt scheduling, so while the actual state save/restore can be interrupted and restarted, the act of actually clearing/setting CR0.TS and the TS_USEDFPU bit together must not. Instead of just adding random "preempt_disable/enable()" calls to what is already excessively ugly code, this introduces some helper functions that mostly mirror the "kernel_fpu_begin/end()" functionality, just for the user state instead. Those helper functions should probably eventually replace the other ad-hoc CR0.TS and TS_USEDFPU tests too, but I'll need to think about it some more: the task switching functionality in particular needs to expose the difference between the 'prev' and 'next' threads, while the new helper functions intentionally were written to only work with 'current'. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-02-15i387: fix sense of sanity checkLinus Torvalds
The check for save_init_fpu() (introduced in commit 5b1cbac37798: "i387: make irq_fpu_usable() tests more robust") was the wrong way around, but I hadn't noticed, because my "tests" were bogus: the FPU exceptions are disabled by default, so even doing a divide by zero never actually triggers this code at all unless you do extra work to enable them. So if anybody did enable them, they'd get one spurious warning. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-02-14Merge tag 'stable/for-linus-fixes-3.3-rc3' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen Two fixes for VCPU offlining; One to fix the string format exposed by the xen-pci[front|back] to conform to the one used in majority of PCI drivers; Two fixes to make the code more resilient to invalid configurations. Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> * tag 'stable/for-linus-fixes-3.3-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen: xenbus_dev: add missing error check to watch handling xen/pci[front|back]: Use %d instead of %1x for displaying PCI devfn. xen pvhvm: do not remap pirqs onto evtchns if !xen_have_vector_callback xen/smp: Fix CPU online/offline bug triggering a BUG: scheduling while atomic. xen/bootup: During bootup suppress XENBUS: Unable to read cpu state
2012-02-13i387: make irq_fpu_usable() tests more robustLinus Torvalds
Some code - especially the crypto layer - wants to use the x86 FP/MMX/AVX register set in what may be interrupt (typically softirq) context. That *can* be ok, but the tests for when it was ok were somewhat suspect. We cannot touch the thread-specific status bits either, so we'd better check that we're not going to try to save FP state or anything like that. Now, it may be that the TS bit is always cleared *before* we set the USEDFPU bit (and only set when we had already cleared the USEDFP before), so the TS bit test may actually have been sufficient, but it certainly was not obviously so. So this explicitly verifies that we will not touch the TS_USEDFPU bit, and adds a few related sanity-checks. Because it seems that somehow AES-NI is corrupting user FP state. The cause is not clear, and this patch doesn't fix it, but while debugging it I really wanted the code to be more obviously correct and robust. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-02-13i387: math_state_restore() isn't called from asmLinus Torvalds
It was marked asmlinkage for some really old and stale legacy reasons. Fix that and the equally stale comment. Noticed when debugging the irq_fpu_usable() bugs. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-02-10Merge branch 'perf-urgent-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip * 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: perf: Fix double start/stop in x86_pmu_start() perf evsel: Fix an issue where perf report fails to show the proper percentage perf tools: Fix prefix matching for kernel maps perf tools: Fix perf stack to non executable on x86_64 perf: Remove deprecated WARN_ON_ONCE()
2012-02-09x86/amd: Fix L1i and L2 cache sharing information for AMD family 15h processorsAndreas Herrmann
For L1 instruction cache and L2 cache the shared CPU information is wrong. On current AMD family 15h CPUs those caches are shared between both cores of a compute unit. This fixes https://bugzilla.kernel.org/show_bug.cgi?id=42607 Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com> Cc: Petkov Borislav <Borislav.Petkov@amd.com> Cc: Dave Jones <davej@redhat.com> Cc: <stable@kernel.org> Link: http://lkml.kernel.org/r/20120208195229.GA17523@alberich.amd.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-02-07perf: Fix double start/stop in x86_pmu_start()Stephane Eranian
The following patch fixes a bug introduced by the following commit: e050e3f0a71b ("perf: Fix broken interrupt rate throttling") The patch caused the following warning to pop up depending on the sampling frequency adjustments: ------------[ cut here ]------------ WARNING: at arch/x86/kernel/cpu/perf_event.c:995 x86_pmu_start+0x79/0xd4() It was caused by the following call sequence: perf_adjust_freq_unthr_context.part() { stop() if (delta > 0) { perf_adjust_period() { if (period > 8*...) { stop() ... start() } } } start() } Which caused a double start and a double stop, thus triggering the assert in x86_pmu_start(). The patch fixes the problem by avoiding the double calls. We pass a new argument to perf_adjust_period() to indicate whether or not the event is already stopped. We can't just remove the start/stop from that function because it's called from __perf_event_overflow where the event needs to be reloaded via a stop/start back-toback call. The patch reintroduces the assertion in x86_pmu_start() which was removed by commit: 84f2b9b ("perf: Remove deprecated WARN_ON_ONCE()") In this second version, we've added calls to disable/enable PMU during unthrottling or frequency adjustment based on bug report of spurious NMI interrupts from Eric Dumazet. Reported-and-tested-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: Stephane Eranian <eranian@google.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: markus@trippelsdorf.de Cc: paulus@samba.org Link: http://lkml.kernel.org/r/20120207133956.GA4932@quad [ Minor edits to the changelog and to the code ] Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-02-07x86/microcode: Remove noisy AMD microcode warningPrarit Bhargava
AMD processors will never support /dev/cpu/microcode updating so just silently fail instead of printing out a warning for every cpu. Signed-off-by: Prarit Bhargava <prarit@redhat.com> Cc: Borislav Petkov <borislav.petkov@amd.com> Link: http://lkml.kernel.org/r/1328552935-965-1-git-send-email-prarit@redhat.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-02-06Merge branch 'kvm-updates/3.3' of git://git.kernel.org/pub/scm/virt/kvm/kvmLinus Torvalds
Fixing a regression with the PMU MSRs when PMU virtualization is disabled, a guest-internal DoS with the SYSCALL instruction, and a dirty memory logging race that may cause live migration to fail. * 'kvm-updates/3.3' of git://git.kernel.org/pub/scm/virt/kvm/kvm: KVM: do not #GP on perf MSR writes when vPMU is disabled KVM: x86: fix missing checks in syscall emulation KVM: x86: extend "struct x86_emulate_ops" with "get_cpuid" KVM: Fix __set_bit() race in mark_page_dirty() during dirty logging
2012-02-03xen pvhvm: do not remap pirqs onto evtchns if !xen_have_vector_callbackStefano Stabellini
CC: stable@kernel.org #2.6.37 and onwards Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2012-02-03xen/smp: Fix CPU online/offline bug triggering a BUG: scheduling while atomic.Konrad Rzeszutek Wilk
When a user offlines a VCPU and then onlines it, we get: NMI watchdog disabled (cpu2): hardware events not enabled BUG: scheduling while atomic: swapper/2/0/0x00000002 Modules linked in: dm_multipath dm_mod xen_evtchn iscsi_boot_sysfs iscsi_tcp libiscsi_tcp libiscsi scsi_transport_iscsi scsi_mod libcrc32c crc32c radeon fbco ttm bitblit softcursor drm_kms_helper xen_blkfront xen_netfront xen_fbfront fb_sys_fops sysimgblt sysfillrect syscopyarea xen_kbdfront xenfs [last unloaded: Pid: 0, comm: swapper/2 Tainted: G O 3.2.0phase15.1-00003-gd6f7f5b-dirty #4 Call Trace: [<ffffffff81070571>] __schedule_bug+0x61/0x70 [<ffffffff8158eb78>] __schedule+0x798/0x850 [<ffffffff8158ed6a>] schedule+0x3a/0x50 [<ffffffff810349be>] cpu_idle+0xbe/0xe0 [<ffffffff81583599>] cpu_bringup_and_idle+0xe/0x10 The reason for this should be obvious from this call-chain: cpu_bringup_and_idle: \- cpu_bringup | \-[preempt_disable] | |- cpu_idle \- play_dead [assuming the user offlined the VCPU] | \ | +- (xen_play_dead) | \- HYPERVISOR_VCPU_off [so VCPU is dead, once user | | onlines it starts from here] | \- cpu_bringup [preempt_disable] | +- preempt_enable_no_reschedule() +- schedule() \- preempt_enable() So we have two preempt_disble() and one preempt_enable(). Calling preempt_enable() after the cpu_bringup() in the xen_play_dead fixes the imbalance. Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2012-02-03perf: Remove deprecated WARN_ON_ONCE()Stephane Eranian
With the new throttling/unthrottling code introduced with commit: e050e3f0a71b ("perf: Fix broken interrupt rate throttling") we occasionally hit two WARN_ON_ONCE() checks in: - intel_pmu_pebs_enable() - intel_pmu_lbr_enable() - x86_pmu_start() The assertions are no longer problematic. There is a valid path where they can trigger but it is harmless. The assertion can be triggered with: $ perf record -e instructions:pp .... Leading to paths: intel_pmu_pebs_enable intel_pmu_enable_event x86_perf_event_set_period x86_pmu_start perf_adjust_freq_unthr_context perf_event_task_tick scheduler_tick And: intel_pmu_lbr_enable intel_pmu_enable_event x86_perf_event_set_period x86_pmu_start perf_adjust_freq_unthr_context. perf_event_task_tick scheduler_tick cpuc->enabled is always on because when we get to perf_adjust_freq_unthr_context() the PMU is not totally disabled. Furthermore when we need to adjust a period, we only stop the event we need to change and not the entire PMU. Thus, when we re-enable, cpuc->enabled is already set. Note that when we stop the event, both pebs and lbr are stopped if necessary (and possible). Signed-off-by: Stephane Eranian <eranian@google.com> Cc: peterz@infradead.org Link: http://lkml.kernel.org/r/20120202110401.GA30911@quad Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-02-02Merge branches 'core-urgent-for-linus', 'perf-urgent-for-linus', ↵Linus Torvalds
'sched-urgent-for-linus' and 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip * 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: bugs, x86: Fix printk levels for panic, softlockups and stack dumps * 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: perf top: Fix number of samples displayed perf tools: Fix strlen() bug in perf_event__synthesize_event_type() perf tools: Fix broken build by defining _GNU_SOURCE in Makefile x86/dumpstack: Remove unneeded check in dump_trace() perf: Fix broken interrupt rate throttling * 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched/rt: Fix task stack corruption under __ARCH_WANT_INTERRUPTS_ON_CTXSW sched: Fix ancient race in do_exit() sched/nohz: Fix nohz cpu idle load balancing state with cpu hotplug sched/s390: Fix compile error in sched/core.c sched: Fix rq->nr_uninterruptible update race * 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/reboot: Remove VersaLogic Menlow reboot quirk x86/reboot: Skip DMI checks if reboot set by user x86: Properly parenthesize cmpxchg() macro arguments
2012-02-01KVM: do not #GP on perf MSR writes when vPMU is disabledGleb Natapov
Return to behaviour perf MSR had before introducing vPMU in case vPMU is disabled. Some guests access those registers unconditionally and do not expect it to fail. Signed-off-by: Gleb Natapov <gleb@redhat.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2012-02-01KVM: x86: fix missing checks in syscall emulationStephan Bärwolf
On hosts without this patch, 32bit guests will crash (and 64bit guests may behave in a wrong way) for example by simply executing following nasm-demo-application: [bits 32] global _start SECTION .text _start: syscall (I tested it with winxp and linux - both always crashed) Disassembly of section .text: 00000000 <_start>: 0: 0f 05 syscall The reason seems a missing "invalid opcode"-trap (int6) for the syscall opcode "0f05", which is not available on Intel CPUs within non-longmodes, as also on some AMD CPUs within legacy-mode. (depending on CPU vendor, MSR_EFER and cpuid) Because previous mentioned OSs may not engage corresponding syscall target-registers (STAR, LSTAR, CSTAR), they remain NULL and (non trapping) syscalls are leading to multiple faults and finally crashs. Depending on the architecture (AMD or Intel) pretended by guests, various checks according to vendor's documentation are implemented to overcome the current issue and behave like the CPUs physical counterparts. [mtosatti: cleanup/beautify code] Signed-off-by: Stephan Baerwolf <stephan.baerwolf@tu-ilmenau.de> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2012-02-01KVM: x86: extend "struct x86_emulate_ops" with "get_cpuid"Stephan Bärwolf
In order to be able to proceed checks on CPU-specific properties within the emulator, function "get_cpuid" is introduced. With "get_cpuid" it is possible to virtually call the guests "cpuid"-opcode without changing the VM's context. [mtosatti: cleanup/beautify code] Signed-off-by: Stephan Baerwolf <stephan.baerwolf@tu-ilmenau.de> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2012-01-30x86/reboot: Remove VersaLogic Menlow reboot quirkMichael D Labriola
This commit removes the reboot quirk originally added by commit e19e074 ("x86: Fix reboot problem on VersaLogic Menlow boards"). Testing with a VersaLogic Ocelot (VL-EPMs-21a rev 1.00 w/ BIOS 6.5.102) revealed the following regarding the reboot hang problem: - v2.6.37 reboot=bios was needed. - v2.6.38-rc1: behavior changed, reboot=acpi is needed, reboot=kbd and reboot=bios results in system hang. - v2.6.38: VersaLogic patch (e19e074 "x86: Fix reboot problem on VersaLogic Menlow boards") was applied prior to v2.6.38-rc7. This patch sets a quirk for VersaLogic Menlow boards that forces the use of reboot=bios, which doesn't work anymore. - v3.2: It seems that commit 660e34c ("x86: Reorder reboot method preferences") changed the default reboot method to acpi prior to v3.0-rc1, which means the default behavior is appropriate for the Ocelot. No VersaLogic quirk is required. The Ocelot board used for testing can successfully reboot w/out having to pass any reboot= arguments for all 3 current versions of the BIOS. Signed-off-by: Michael D Labriola <michael.d.labriola@gmail.com> Cc: Matthew Garrett <mjg@redhat.com> Cc: Michael D Labriola <mlabriol@gdeb.com> Cc: Kushal Koolwal <kushalkoolwal@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/87vcnub9hu.fsf@gmail.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-01-30x86/reboot: Skip DMI checks if reboot set by userMichael D Labriola
Skip DMI checks for vendor specific reboot quirks if the user passed in a reboot= arg on the command line - we should never override user choices. Signed-off-by: Michael D Labriola <michael.d.labriola@gmail.com> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: Michael D Labriola <mlabriol@gdeb.com> Cc: Matthew Garrett <mjg@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/87wr8ab9od.fsf@gmail.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-01-28Merge branch 'stable/for-linus-fixes-3.3' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen * 'stable/for-linus-fixes-3.3' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen: xen/granttable: Disable grant v2 for HVM domains. x86: xen: size struct xen_spinlock to always fit in arch_spinlock_t
2012-01-28x86/dumpstack: Remove unneeded check in dump_trace()Dan Carpenter
Smatch complains that we have some inconsistent NULL checking. If "task" were NULL then it would lead to a NULL dereference later. We can remove this test because earlier on in the function we have: if (!task) task = current; Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Namhyung Kim <namhyung@gmail.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Clemens Ladisch <clemens@ladisch.de> Link: http://lkml.kernel.org/r/20120128105246.GA25092@elgon.mountain Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-01-27Merge commit 'v3.3-rc1' into stable/for-linus-fixes-3.3Konrad Rzeszutek Wilk
* commit 'v3.3-rc1': (9775 commits) Linux 3.3-rc1 x86, syscall: Need __ARCH_WANT_SYS_IPC for 32 bits qnx4: don't leak ->BitMap on late failure exits qnx4: reduce the insane nesting in qnx4_checkroot() qnx4: di_fname is an array, for crying out loud... KEYS: Permit key_serial() to be called with a const key pointer keys: fix user_defined key sparse messages ima: fix cred sparse warning uml: fix compile for x86-64 MPILIB: Add a missing ENOMEM check tpm: fix (ACPI S3) suspend regression nvme: fix merge error due to change of 'make_request_fn' fn type xen: using EXPORT_SYMBOL requires including export.h gpio: tps65910: Use correct offset for gpio initialization acpi/apei/einj: Add extensions to EINJ from rev 5.0 of acpi spec intel_idle: Split up and provide per CPU initialization func ACPI processor: Remove unneeded variable passed by acpi_processor_hotadd_init V2 tg3: Fix single-vector MSI-X code openvswitch: Fix multipart datapath dumps. ipv6: fix per device IP snmp counters ...
2012-01-26bugs, x86: Fix printk levels for panic, softlockups and stack dumpsPrarit Bhargava
rsyslog will display KERN_EMERG messages on a connected terminal. However, these messages are useless/undecipherable for a general user. For example, after a softlockup we get: Message from syslogd@intel-s3e37-04 at Jan 25 14:18:06 ... kernel:Stack: Message from syslogd@intel-s3e37-04 at Jan 25 14:18:06 ... kernel:Call Trace: Message from syslogd@intel-s3e37-04 at Jan 25 14:18:06 ... kernel:Code: ff ff a8 08 75 25 31 d2 48 8d 86 38 e0 ff ff 48 89 d1 0f 01 c8 0f ae f0 48 8b 86 38 e0 ff ff a8 08 75 08 b1 01 4c 89 e0 0f 01 c9 <e8> ea 69 dd ff 4c 29 e8 48 89 c7 e8 0f bc da ff 49 89 c4 49 89 This happens because the printk levels for these messages are incorrect. Only an informational message should be displayed on a terminal. I modified the printk levels for various messages in the kernel and tested the output by using the drivers/misc/lkdtm.c kernel modules (ie, softlockups, panics, hard lockups, etc.) and confirmed that the console output was still the same and that the output to the terminals was correct. For example, in the case of a softlockup we now see the much more informative: Message from syslogd@intel-s3e37-04 at Jan 25 10:18:06 ... BUG: soft lockup - CPU4 stuck for 60s! instead of the above confusing messages. AFAICT, the messages no longer have to be KERN_EMERG. In the most important case of a panic we set console_verbose(). As for the other less severe cases the correct data is output to the console and /var/log/messages. Successfully tested by me using the drivers/misc/lkdtm.c module. Signed-off-by: Prarit Bhargava <prarit@redhat.com> Cc: dzickus@redhat.com Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/1327586134-11926-1-git-send-email-prarit@redhat.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-16 01:44:27 +0000