- 05 3月, 2012 18 次提交
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由 Christian Borntraeger 提交于
On some cpus the overhead for virtualization instructions is in the same range as a system call. Having to call multiple ioctls to get set registers will make certain userspace handled exits more expensive than necessary. Lets provide a section in kvm_run that works as a shared save area for guest registers. We also provide two 64bit flags fields (architecture specific), that will specify 1. which parts of these fields are valid. 2. which registers were modified by userspace Each bit for these flag fields will define a group of registers (like general purpose) or a single register. Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com> Signed-off-by: NAvi Kivity <avi@redhat.com>
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由 Christian Borntraeger 提交于
There are several places in the kvm module, which set the prefix register. Since we need to flush the cpu, lets combine this operation into a helper function. This helper will also explicitely mask out the unused bits. Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com> Signed-off-by: NAvi Kivity <avi@redhat.com>
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由 Boris Ostrovsky 提交于
In some cases guests should not provide workarounds for errata even when the physical processor is affected. For example, because of erratum 400 on family 10h processors a Linux guest will read an MSR (resulting in VMEXIT) before going to idle in order to avoid getting stuck in a non-C0 state. This is not necessary: HLT and IO instructions are intercepted and therefore there is no reason for erratum 400 workaround in the guest. This patch allows us to present a guest with certain errata as fixed, regardless of the state of actual hardware. Signed-off-by: NBoris Ostrovsky <boris.ostrovsky@amd.com> Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com> Signed-off-by: NAvi Kivity <avi@redhat.com>
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由 Davidlohr Bueso 提交于
We can remove the first ->nx state assignment since it is assigned afterwards anyways. Signed-off-by: NDavidlohr Bueso <dave@gnu.org> Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com> Signed-off-by: NAvi Kivity <avi@redhat.com>
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由 Carsten Otte 提交于
This patch fixes the return code of kvm_arch_vcpu_ioctl in case of an unkown ioctl number. Signed-off-by: NCarsten Otte <cotte@de.ibm.com> Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com> Signed-off-by: NAvi Kivity <avi@redhat.com>
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由 Carsten Otte 提交于
This patch announces a new capability KVM_CAP_S390_UCONTROL that indicates that kvm can now support virtual machines that are controlled by userspace. Signed-off-by: NCarsten Otte <cotte@de.ibm.com> Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com> Signed-off-by: NAvi Kivity <avi@redhat.com>
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由 Carsten Otte 提交于
This patch fixes definition of the idle_mask and the local_int array in kvm_s390_float_interrupt. Previous definition had 64 cpus max hardcoded instead of using KVM_MAX_VCPUS. Signed-off-by: NCarsten Otte <cotte@de.ibm.com> Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com> Signed-off-by: NAvi Kivity <avi@redhat.com>
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由 Carsten Otte 提交于
This patch makes sure user controlled virtual machines do not use a system control area (sca). This is needed in order to create virtual machines with more cpus than the size of the sca [64]. Signed-off-by: NCarsten Otte <cotte@de.ibm.com> Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com> Signed-off-by: NAvi Kivity <avi@redhat.com>
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由 Carsten Otte 提交于
This patch allows the user to fault in pages on a virtual cpus address space for user controlled virtual machines. Typically this is superfluous because userspace can just create a mapping and let the kernel's page fault logic take are of it. There is one exception: SIE won't start if the lowcore is not present. Normally the kernel takes care of this [handle_validity() in arch/s390/kvm/intercept.c] but since the kernel does not handle intercepts for user controlled virtual machines, userspace needs to be able to handle this condition. Signed-off-by: NCarsten Otte <cotte@de.ibm.com> Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com> Signed-off-by: NAvi Kivity <avi@redhat.com>
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由 Carsten Otte 提交于
This patch disables the in-kernel interrupt stack for KVM virtual machines that are controlled by user. Userspace has to take care of handling interrupts on its own. Signed-off-by: NCarsten Otte <cotte@de.ibm.com> Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com> Signed-off-by: NAvi Kivity <avi@redhat.com>
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由 Carsten Otte 提交于
This patch disables in-kernel handling of SIE intercepts for user controlled virtual machines. All intercepts are passed to userspace via KVM_EXIT_SIE exit reason just like SIE intercepts that cannot be handled in-kernel for regular KVM guests. Signed-off-by: NCarsten Otte <cotte@de.ibm.com> Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com> Signed-off-by: NAvi Kivity <avi@redhat.com>
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由 Carsten Otte 提交于
This patch exports the s390 SIE hardware control block to userspace via the mapping of the vcpu file descriptor. In order to do so, a new arch callback named kvm_arch_vcpu_fault is introduced for all architectures. It allows to map architecture specific pages. Signed-off-by: NCarsten Otte <cotte@de.ibm.com> Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com> Signed-off-by: NAvi Kivity <avi@redhat.com>
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由 Carsten Otte 提交于
This patch introduces a new exit reason in the kvm_run structure named KVM_EXIT_S390_UCONTROL. This exit indicates, that a virtual cpu has regognized a fault on the host page table. The idea is that userspace can handle this fault by mapping memory at the fault location into the cpu's address space and then continue to run the virtual cpu. Signed-off-by: NCarsten Otte <cotte@de.ibm.com> Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com> Signed-off-by: NAvi Kivity <avi@redhat.com>
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由 Carsten Otte 提交于
This patch introduces two ioctls for virtual cpus, that are only valid for kernel virtual machines that are controlled by userspace. Each virtual cpu has its individual address space in this mode of operation, and each address space is backed by the gmap implementation just like the address space for regular KVM guests. KVM_S390_UCAS_MAP allows to map a part of the user's virtual address space to the vcpu. Starting offset and length in both the user and the vcpu address space need to be aligned to 1M. KVM_S390_UCAS_UNMAP can be used to unmap a range of memory from a virtual cpu in a similar way. Signed-off-by: NCarsten Otte <cotte@de.ibm.com> Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com> Signed-off-by: NAvi Kivity <avi@redhat.com>
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由 Carsten Otte 提交于
This patch introduces a new config option for user controlled kernel virtual machines. It introduces a parameter to KVM_CREATE_VM that allows to set bits that alter the capabilities of the newly created virtual machine. The parameter is passed to kvm_arch_init_vm for all architectures. The only valid modifier bit for now is KVM_VM_S390_UCONTROL. This requires CAP_SYS_ADMIN privileges and creates a user controlled virtual machine on s390 architectures. Signed-off-by: NCarsten Otte <cotte@de.ibm.com> Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com> Signed-off-by: NAvi Kivity <avi@redhat.com>
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由 Xiao Guangrong 提交于
get_written_sptes is called twice in kvm_mmu_pte_write, one of them can be removed Signed-off-by: NXiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com> Signed-off-by: NAvi Kivity <avi@redhat.com>
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由 Takuya Yoshikawa 提交于
Signed-off-by: NTakuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp> Signed-off-by: NAvi Kivity <avi@redhat.com>
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由 Takuya Yoshikawa 提交于
There is only one user of it and for_each_set_bit() does the same. Signed-off-by: NTakuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp> Signed-off-by: NAvi Kivity <avi@redhat.com>
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- 27 2月, 2012 2 次提交
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由 Heiko Carstens 提交于
The new is_compat_task() define for the !COMPAT case in include/linux/compat.h conflicts with a similar define in arch/s390/include/asm/compat.h. This is the minimal patch which fixes the build issues. Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Ohad Ben-Cohen 提交于
omap3isp depends on omap's iommu and will fail to probe if initialized before it (which always happen if they are builtin). Make omap's iommu subsys_initcall as an interim solution until the probe deferral mechanism is merged. Reported-by: NJames <angweiyang@gmail.com> Debugged-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: NOhad Ben-Cohen <ohad@wizery.com> Cc: stable <stable@vger.kernel.org> Cc: Tony Lindgren <tony@atomide.com> Cc: Hiroshi Doyu <hdoyu@nvidia.com> Cc: Joerg Roedel <Joerg.Roedel@amd.com> Signed-off-by: NJoerg Roedel <joerg.roedel@amd.com>
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- 24 2月, 2012 7 次提交
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由 Danny Kukawka 提交于
arch/arm/mach-shmobile/board-ag5evm.c: included 'linux/dma-mapping.h' twice, remove the duplicate. Signed-off-by: NDanny Kukawka <danny.kukawka@bisect.de> Signed-off-by: NPaul Mundt <lethal@linux-sh.org>
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由 Magnus Damm 提交于
Fix the bit field width information for the IPSR4 register in the r8a7779 pin function controller (PFC). Without this fix the Marzen board fails to receive data over the serial console due to misconfigured pin function for the RX pin. Signed-off-by: NMagnus Damm <damm@opensource.se> Tested-by: NKuninori Morimoto <kuninori.morimoto.gx@renesas.com> Tested-by: NSimon Horman <horms@verge.net.au> Signed-off-by: NPaul Mundt <lethal@linux-sh.org>
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由 Magnus Damm 提交于
Convert the sh73a0 SMP code to use 32-bit PSTR access. This fixes wakeup from deep sleep for sh73a0 secondary CPUs. Signed-off-by: NMagnus Damm <damm@opensource.se> Signed-off-by: NPaul Mundt <lethal@linux-sh.org>
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由 Phil Edworthy 提交于
Signed-off-by: NPhil Edworthy <phil.edworthy@renesas.com> Signed-off-by: NPaul Mundt <lethal@linux-sh.org>
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由 Shimoda, Yoshihiro 提交于
The latest sh_eth driver needs a resource of TSU in the channel 1, if the controller has TSU registers. So, this patch adds the resource. Signed-off-by: NYoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com> Signed-off-by: NPaul Mundt <lethal@linux-sh.org>
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由 Rusty Russell 提交于
This has been obsolescent for a while; time for the final push. Signed-off-by: NRusty Russell <rusty@rustcorp.com.au> Cc: Paul Mundt <lethal@linux-sh.org> Cc: linux-sh@vger.kernel.org Signed-off-by: NPaul Mundt <lethal@linux-sh.org>
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由 Masanari Iida 提交于
Correct spelling "erorr" to "error" in arch/sh/drivers/pci/pci-sh7780.c Signed-off-by: NMasanari Iida <standby24x7@gmail.com> Signed-off-by: NPaul Mundt <lethal@linux-sh.org>
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- 22 2月, 2012 6 次提交
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由 Borislav Petkov 提交于
141168c3 ("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: NBorislav Petkov <bp@alien8.de> Acked-by: NKevin 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.comSigned-off-by: NIngo Molnar <mingo@elte.hu>
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由 Benjamin Herrenschmidt 提交于
We have a few problems when returning to userspace. This is a quick set of fixes for 3.3, I'll look into a more comprehensive rework for 3.4. This fixes: - We kept interrupts soft-disabled when schedule'ing or calling do_signal when returning to userspace as a result of a hardware interrupt. - Rename do_signal to do_notify_resume like all other archs (and do_signal_pending back to do_signal, which it was before Roland changed it). - Add the missing call to key_replace_session_keyring() to do_notify_resume(). Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org> ---
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由 Michael Ellerman 提交于
In commit 54321242 ("Disable interrupts early in Program Check"), we switched from enabling to disabling interrupts in program_check_common. Whereas ENABLE_INTS leaves r3 untouched, if lockdep is enabled DISABLE_INTS calls into lockdep code and will clobber r3. That means we pass a bogus struct pt_regs* into program_check_exception() and all hell breaks loose. So load our regs pointer into r3 after we call DISABLE_INTS. Signed-off-by: NMichael Ellerman <michael@ellerman.id.au> Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
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由 Rusty Russell 提交于
This has been obsolescent for a while; time for the final push. In adjacent context, replaced old cpus_* with cpumask_*. Signed-off-by: NRusty Russell <rusty@rustcorp.com.au> Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
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由 Linus Torvalds 提交于
The 'poll()' system call timeout parameter is supposed to be 'int', not 'long'. Now, the reason this matters is that right now 32-bit compat mode is broken on at least x86-64, because the 32-bit code just calls 'sys_poll()' directly on x86-64, and the 32-bit argument will have been zero-extended, turning a signed 'int' into a large unsigned 'long' value. We could just introduce a 'compat_sys_poll()' function for this, and that may eventually be what we have to do, but since the actual standard poll() semantics is *supposed* to be 'int', and since at least on x86-64 glibc sign-extends the argument before invocing the system call (so nobody can actually use a 64-bit timeout value in user space _anyway_, even in 64-bit binaries), the simpler solution would seem to be to just fix the definition of the system call to match what it should have been from the very start. If it turns out that somebody somehow circumvents the user-level libc 64-bit sign extension and actually uses a large unsigned 64-bit timeout despite that not being how poll() is supposed to work, we will need to do the compat_sys_poll() approach. Reported-by: NThomas Meyer <thomas@m3y3r.de> Acked-by: NEric Dumazet <eric.dumazet@gmail.com> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Eric Paris 提交于
Both bugs being fixed were introduced in: 29ef73b7 Include linux/audit.h to fix below build errors: CC arch/arm/kernel/ptrace.o arch/arm/kernel/ptrace.c: In function 'syscall_trace': arch/arm/kernel/ptrace.c:919: error: implicit declaration of function 'audit_syscall_exit' arch/arm/kernel/ptrace.c:921: error: implicit declaration of function 'audit_syscall_entry' arch/arm/kernel/ptrace.c:921: error: 'AUDIT_ARCH_ARMEB' undeclared (first use in this function) arch/arm/kernel/ptrace.c:921: error: (Each undeclared identifier is reported only once arch/arm/kernel/ptrace.c:921: error: for each function it appears in.) make[1]: *** [arch/arm/kernel/ptrace.o] Error 1 make: *** [arch/arm/kernel] Error 2 This part of the patch is: Reported-by: NAxel Lin <axel.lin@gmail.com> Reported-by: NPeter Ujfalusi <peter.ujfalusi@ti.com> (They both provided patches to fix it) This patch also (at the request of the list) fixes the fact that ARM has both LE and BE versions however the audit code was called as if it was always BE. If audit userspace were to try to interpret the bits it got from a LE system it would obviously do so incorrectly. Fix this by using the right arch flag on the right system. This part of the patch is: Reported-by: NRussell King - ARM Linux <linux@arm.linux.org.uk> Signed-off-by: NEric Paris <eparis@redhat.com> Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>
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- 21 2月, 2012 7 次提交
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由 Russell King 提交于
The voltage domain code wants the voltage tables, which are in the opp*.c files. These files aren't built when PM_OPP is disabled, causing the following build errors at link time: twl-common.c:(.init.text+0x2e48): undefined reference to `omap34xx_vddmpu_volt_data' twl-common.c:(.init.text+0x2e4c): undefined reference to `omap34xx_vddcore_volt_data' twl-common.c:(.init.text+0x2e5c): undefined reference to `omap36xx_vddmpu_volt_data' twl-common.c:(.init.text+0x2e60): undefined reference to `omap36xx_vddcore_volt_data' twl-common.c:(.init.text+0x2830): undefined reference to `omap44xx_vdd_mpu_volt_data' twl-common.c:(.init.text+0x283c): undefined reference to `omap44xx_vdd_iva_volt_data' twl-common.c:(.init.text+0x2844): undefined reference to `omap44xx_vdd_core_volt_data' Acked-by: NKevin Hilman <khilman@ti.com> Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>
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由 Myron Stowe 提交于
The patch series to re-factor PCI's 'latency timer' setup (re: http://marc.info/?l=linux-kernel&m=131983853831049&w=2) forgot to remove the ARM specific definition of 'pcibios_max_latency' once such had been moved into the pci core resulting in ARM related compile errors - drivers/built-in.o:(.data+0x230): multiple definition of `pcibios_max_latency' arch/arm/common/built-in.o:(.data+0x40c): first defined here make[1]: *** [vmlinux.o] Error 1 In the series, patch 2/16 (commit 168c8619) converted the ARM specific version of 'pcibios_set_master()' to a non-inlined version. This was done in preperation for hosting it up into PCI's core, which was done in patch 10/16 (commit 96c55900) of the series (and where the removal of ARM's 'pcibios_max_latency' was overlooked). Reported-by: NRussell King <rmk+kernel@arm.linux.org.uk> Signed-off-by: NMyron Stowe <myron.stowe@redhat.com> Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>
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由 Santosh Shilimkar 提交于
Current ARM local timer code registers CPUFREQ notifiers even in case the twd_timer_setup() isn't called. That seems to be wrong and would eventually lead to kernel crash on the CPU frequency transitions on the SOCs where the local timer doesn't exist or broken because of hardware BUG. Fix it by testing twd_evt and *__this_cpu_ptr(twd_evt). The issue was observed with v3.3-rc3 and building an OMAP2+ kernel on OMAP3 SOC which doesn't have TWD. Below is the dump for reference : Unable to handle kernel paging request at virtual address 007e900 pgd = cdc20000 [007e9000] *pgd=00000000 Internal error: Oops: 5 [#1] SMP Modules linked in: CPU: 0 Not tainted (3.3.0-rc3-pm+debug+initramfs #9) PC is at twd_update_frequency+0x34/0x48 LR is at twd_update_frequency+0x10/0x48 pc : [<c001382c>] lr : [<c0013808>] psr: 60000093 sp : ce311dd8 ip : 00000000 fp : 00000000 r10: 00000000 r9 : 00000001 r8 : ce310000 r7 : c0440458 r6 : c00137f8 r5 : 00000000 r4 : c0947a74 r3 : 00000000 r2 : 007e9000 r1 : 00000000 r0 : 00000000 Flags: nZCv IRQs off FIQs on Mode SVC_32 ISA ARM Segment usr Control: 10c5387d Table: 8dc20019 DAC: 00000015 Process sh (pid: 599, stack limit = 0xce3102f8) Stack: (0xce311dd8 to 0xce312000) 1dc0: 6000c 1de0: 00000001 00000002 00000000 00000000 00000000 00000000 00000 1e00: ffffffff c093d8f0 00000000 ce311ebc 00000001 00000001 ce310 1e20: c001386c c0437c4c c0e95b60 c0e95ba8 00000001 c0e95bf8 ffff4 1e40: 00000000 00000000 c005ef74 ce310000 c0435cf0 ce311ebc 00000 1e60: ce352b40 0007a120 c08d5108 c08ba040 c08ba040 c005f030 00000 1e80: c08bc554 c032fe2c 0007a120 c08d4b64 ce352b40 c08d8618 ffff8 1ea0: c08ba040 c033364c ce311ecc c0433b50 00000002 ffffffea c0330 1ec0: 0007a120 0007a120 22222201 00000000 22222222 00000000 ce357 1ee0: ce3d6000 cdc2aed8 ce352ba0 c0470164 00000002 c032f47c 00034 1f00: c0331cac ce352b40 00000007 c032f6d0 ce352bbc 0003d090 c0930 1f20: c093d8bc c03306a4 00000007 ce311f80 00000007 cdc2aec0 ce358 1f40: ce8d20c0 00000007 b6fe5000 ce311f80 00000007 ce310000 0000c 1f60: c000de74 ce987400 ce8d20c0 b6fe5000 00000000 00000000 0000c 1f80: 00000000 00000000 001fbac8 00000000 00000007 001fbac8 00004 1fa0: c000df04 c000dd60 00000007 001fbac8 00000001 b6fe5000 00000 1fc0: 00000007 001fbac8 00000007 00000004 b6fe5000 00000000 00202 1fe0: 00000000 beb565f8 00101ffc 00008e8c 60000010 00000001 00000 [<c001382c>] (twd_update_frequency+0x34/0x48) from [<c008ac4c>] ) [<c008ac4c>] (smp_call_function_single+0x17c/0x1c8) from [<c0013) [<c0013890>] (twd_cpufreq_transition+0x24/0x30) from [<c0437c4c>) [<c0437c4c>] (notifier_call_chain+0x44/0x84) from [<c005efe4>] () [<c005efe4>] (__srcu_notifier_call_chain+0x70/0xa4) from [<c005f) [<c005f030>] (srcu_notifier_call_chain+0x18/0x20) from [<c032fe2) [<c032fe2c>] (cpufreq_notify_transition+0xc8/0x1b0) from [<c0333) [<c033364c>] (omap_target+0x1b4/0x28c) from [<c032f47c>] (__cpuf) [<c032f47c>] (__cpufreq_driver_target+0x50/0x64) from [<c0331d24) [<c0331d24>] (cpufreq_set+0x78/0x98) from [<c032f6d0>] (store_sc) [<c032f6d0>] (store_scaling_setspeed+0x5c/0x74) from [<c03306a4>) [<c03306a4>] (store+0x58/0x74) from [<c014d868>] (sysfs_write_fi) [<c014d868>] (sysfs_write_file+0x80/0xb4) from [<c00f2c2c>] (vfs) [<c00f2c2c>] (vfs_write+0xa8/0x138) from [<c00f2e9c>] (sys_write) [<c00f2e9c>] (sys_write+0x40/0x6c) from [<c000dd60>] (ret_fast_s) Code: e594300c e792210c e1a01000 e5840004 (e7930002) ---[ end trace 5da3b5167c1ecdda ]--- Reported-by: NKevin Hilman <khilman@ti.com> Acked-by: NMarc Zyngier <marc.zyngier@arm.com> Tested-by: NKevin Hilman <khilman@ti.com> Signed-off-by: NSantosh Shilimkar <santosh.shilimkar@ti.com> Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>
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由 Linus Torvalds 提交于
(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: NJosh Boyer <jwboyer@gmail.com> Reported-and-tested-by: NJongman Heo <jongman.heo@samsung.com> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Steven Rostedt 提交于
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.comSuggested-by: NLinus Torvalds <torvalds@linux-foundation.org> Cc: H. Peter Anvin <hpa@zytor.com> Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
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由 Linus Torvalds 提交于
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: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Linus Torvalds 提交于
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: NLinus Torvalds <torvalds@linux-foundation.org>
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