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2015-02-17MIPS: Emulate the new MIPS R6 BEQZC and JIC instructionsMarkos Chandras1-1/+1
MIPS R6 uses the <R6 ldc2 opcode for the new BEQZC and JIC instructions Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2015-02-17MIPS: Emulate the new MIPS R6 BALC instructionMarkos Chandras1-1/+1
MIPS R6 uses the <R6 swc2 opcode for the new BALC instructions. Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2015-02-17MIPS: Emulate the new MIPS R6 BNVC, BNEC and BNEZLAC instructionsMarkos Chandras1-1/+1
MIPS R6 uses the <R6 DADDI opcode for the new BNVC, BNEC and BNEZLAC instructions. Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2015-02-17MIPS: Emulate the new MIPS R6 BOVC, BEQC and BEQZALC instructionsMarkos Chandras1-1/+1
MIPS R6 uses the <R6 ADDI opcode for the new BOVC, BEQC and BEQZALC instructions. Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2015-02-17MIPS: Emulate the new MIPS R6 branch compact (BC) instructionMarkos Chandras1-1/+1
MIPS R6 uses the <R6 LWC2 opcode for the new BC instruction. Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2015-02-17MIPS: Emulate the BC1{EQ,NE}Z FPU instructionsMarkos Chandras1-1/+2
MIPS R6 introduced the following two branch instructions for COP1: BC1EQZ: Branch if Cop1 (FPR) Register Bit 0 is Equal to Zero BC1NEZ: Branch if Cop1 (FPR) Register Bit 0 is Not Equal to Zero Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2015-02-17MIPS: kernel: Prepare the JR instruction for emulation on MIPS R6Markos Chandras1-0/+3
The MIPS R6 JR instruction is an alias to the JALR one, so it may need emulation for non-R6 userlands. Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2015-02-17MIPS: kernel: r4k_switch: Add support for MIPS R6Leonid Yegoshin1-5/+7
Add the MIPS R6 related preprocessor definitions for save/restore FPU related functions. We also set the appropriate ISA level so the final return instruction "jr ra" will produce the correct opcode on R6. Signed-off-by: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com> Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2015-02-17MIPS: kernel: proc: Add MIPS R6 support to /proc/cpuinfoMarkos Chandras1-0/+3
Print 'mips64r6' and/or 'mips32r6' if the kernel is running on a MIPS R6 core. Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2015-02-17MIPS: asm: local: Set the appropriate ISA level for MIPS R6Markos Chandras1-2/+3
MIPS R6 changed the opcodes for LL/SC instructions so we need to set the appropriate ISA level. Cc: Matthew Fortune <Matthew.Fortune@imgtec.com> Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2015-02-17MIPS: asm: spinlock: Replace "sub" instruction with "addiu"Markos Chandras1-5/+2
"sub $reg, imm" is not a real MIPS instruction. The assembler can replace that with "addi $reg, -imm". However, addi has been removed from R6, so we replace the "sub" instruction with the "addiu" one. Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2015-02-17MIPS: asm: futex: Set the appropriate ISA level for MIPS R6Markos Chandras1-4/+4
MIPS R6 changed the opcodes for LL/SC instructions so we need to set the appropriate ISA level. Cc: Matthew Fortune <Matthew.Fortune@imgtec.com> Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2015-02-17MIPS: asm: bitops: Update ISA constraints for MIPS R6 supportMarkos Chandras1-15/+15
MIPS R6 changed the opcodes for LL/SC instructions so we need to set the correct ISA level. Cc: Matthew Fortune <Matthew.Fortune@imgtec.com> Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2015-02-17MIPS: asm: atomic: Update ISA constraints for MIPS R6 supportMarkos Chandras1-6/+6
MIPS R6 changed the opcodes for LL/SC instructions so we need to set the correct ISA level. Cc: Matthew Fortune <Matthew.Fortune@imgtec.com> Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2015-02-17MIPS: asm: cmpxchg: Update ISA constraints for MIPS R6 supportMarkos Chandras1-5/+5
MIPS R6 changed the opcodes for LL/SC instructions so we need to set the correct ISA. Cc: Matthew Fortune <Matthew.Fortune@imgtec.com> Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2015-02-17MIPS: Use the new "ZC" constraint for MIPS R6Markos Chandras1-1/+6
GCC versions supporting MIPS R6 use the ZC constraint to enforce a 9-bit offset for MIPS R6. We will use that for all MIPS R6 LL/SC instructions. Cc: Matthew Fortune <Matthew.Fortune@imgtec.com> Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2015-02-17MIPS: asm: Rename GCC_OFF12_ASM to GCC_OFF_SMALL_ASMMarkos Chandras9-93/+93
The GCC_OFF12_ASM macro is used for 12-bit immediate constrains but we will also use it for 9-bit constrains on MIPS R6 so we rename it to something more appropriate. Cc: Maciej W. Rozycki <macro@linux-mips.org> Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2015-02-17MIPS: asm: spram: Add new symbol for MIPS scratch pad storageMarkos Chandras1-2/+2
MIPS R6, just like MIPS R2, have scratch pad storage, so add a new symbol which is selected by MIPS R2 and R6. Link: http://www.linux-mips.org/archives/linux-mips/2015-01/msg00389.html Cc: Maciej W. Rozycki <macro@linux-mips.org> Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2015-02-17MIPS: asm: r4kcache: Add MIPS R6 cache unroll functionsMarkos Chandras1-2/+148
MIPS R6 changed the 'cache' instruction opcode and reduced the offset field to 8 bits. This means we now have to adjust the base register every 256 bytes and as a result of which we can no longer use the previous cache functions. Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2015-02-17MIPS: asm: irqflags: Add MIPS R6 related definitionsMarkos Chandras1-3/+4
Add the MIPS R6 related definitions to the IRQ related macros Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2015-02-17MIPS: asm: hazards: Add MIPSR6 definitionsMarkos Chandras1-4/+5
Add the MIPSR6 related definitions to MIPS hazards Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2015-02-17MIPS: asm: cpu: Add MIPSR6 ISA definitionsLeonid Yegoshin2-6/+20
Add MIPS R6 to the ISA definitions Signed-off-by: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com> Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2015-02-17MIPS: Use generic checksum functions for MIPS R6Markos Chandras2-0/+6
The following instructions have been removed from MIPS R6 ulw, ulh, swl, lwr, lwl, swr. However, all of them are used in the MIPS specific checksum implementation. As a result of which, we will use the generic checksum on MIPS R6 Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2015-02-17MIPS: asm: asmmacro: Replace "add" instructions with "addu"Markos Chandras1-2/+2
The "add" instruction is actually a macro in binutils and depending on the size of the immediate it can expand to an "addi" instruction. However, the "addi" instruction traps on overflows which is not something we want on address calculation. Link: http://www.linux-mips.org/archives/linux-mips/2015-01/msg00121.html Cc: Paul Burton <paul.burton@imgtec.com> Cc: Maciej W. Rozycki <macro@linux-mips.org> Cc: <stable@vger.kernel.org> # v3.15+ Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2015-02-17MIPS: asm: asmmacro: Add MIPS R6 support to the simple EI/DI variantsLeonid Yegoshin1-1/+1
EI/DI instructions are available in MIPS R6 so add the needed definitions. Signed-off-by: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com> Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2015-02-17MIPS: asm: stackframe: Do not preserve the HI/LO registers on MIPS R6Leonid Yegoshin1-4/+4
The HI/LO registers have been removed from MIPS R6. Instructions such as MULT and DIV have been replaced with a new pair of instructions for the HI/LO operations for example: MULT -> MUL, MUH DIV -> DIV, MOD So we avoid preserving the pre-R6 HI/LO registers in MIPS R6 Signed-off-by: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com> Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2015-02-17MIPS: asm: module: define MODULE_PROC_FAMILY for MIPS R6Leonid Yegoshin1-0/+4
Define the MODULE_PROC_FAMILY for the MIPS R6 ISA. Signed-off-by: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com> Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2015-02-17MIPS: asm: compiler: Add new macros to set ISA and arch asm annotationsMarkos Chandras1-0/+13
There are certain places where the code uses .set mips32 or .set mips64 or .set arch=r4000. In preparation of MIPS R6 support, and in order to use as less #ifdefs as possible, we define new macros to set similar annotations for MIPS R6. Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2015-02-16MIPS: mm: Add MIPS R6 instruction encodingsLeonid Yegoshin1-3/+6
MIPS R6 defines new opcodes for ll, sc, cache and pref instructions so we need to take these into consideration in the micro-assembler. Signed-off-by: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com> Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2015-02-16MIPS: Add cases for CPU_QEMU_GENERICLeonid Yegoshin1-0/+7
Add a CPU_QEMU_GENERIC case to various switch statements. Signed-off-by: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com> Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2015-02-16MIPS: Add generic QEMU PRid and cpu type identifiersLeonid Yegoshin1-0/+3
Latest versions of QEMU added support for mips32r6-generic and mips64r6-generic cpu types so add related definitions in preparation of MIPS R6 support. This is also used for QEMU R2 generic cpus. Signed-off-by: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com> Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2015-02-16MIPS: HTW: Prevent accidental HTW start due to nested htw_{start, stop}Markos Chandras3-7/+29
activate_mm() and switch_mm() call get_new_mmu_context() which in turn can enable the HTW before the entryhi is changed with the new ASID. Since the latter will enable the HTW in local_flush_tlb_all(), then there is a small timing window where the HTW is running with the new ASID but with an old pgd since the TLBMISS_HANDLER_SETUP_PGD hasn't assigned a new one yet. In order to prevent that, we introduce a simple htw counter to avoid starting HTW accidentally due to nested htw_{start,stop}() sequences. Moreover, since various IPI calls can enforce TLB flushing operations on a different core, such an operation may interrupt another htw_{stop,start} in progress leading inconsistent updates of the htw_seq variable. In order to avoid that, we disable the interrupts whenever we update that variable. Signed-off-by: Markos Chandras <markos.chandras@imgtec.com> Cc: <stable@vger.kernel.org> # 3.17+ Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/9118/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2015-02-16MIPS: asm: pgtable: Prevent HTW race when updating PTEsMarkos Chandras1-10/+4
Whenever we modify a page table entry, we need to ensure that the HTW will not fetch a stable entry. And for that to happen we need to ensure that HTW is stopped before we modify the said entry otherwise the HTW may already be in the process of reading that entry and fetching the old information. As a result of which, we replace the htw_reset() calls with htw_{stop,start} in more appropriate places. This also removes the remaining users of htw_reset() and as a result we drop that macro Signed-off-by: Markos Chandras <markos.chandras@imgtec.com> Cc: <stable@vger.kernel.org> # 3.17+ Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/9116/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2015-02-16MIPS: asm: pgtable: Add c0 hazards on HTW start/stop sequencesMarkos Chandras1-4/+6
When we use htw_{start,stop}() outside of htw_reset(), we need to ensure that c0 changes have been propagated properly before we attempt to continue with subsequence memory operations. Signed-off-by: Markos Chandras <markos.chandras@imgtec.com> Cc: <stable@vger.kernel.org> # 3.17+ Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/9114/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2015-02-14Merge git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6Linus Torvalds2-7/+15
Pull crypto update from Herbert Xu: "Here is the crypto update for 3.20: - Added 192/256-bit key support to aesni GCM. - Added MIPS OCTEON MD5 support. - Fixed hwrng starvation and race conditions. - Added note that memzero_explicit is not a subsitute for memset. - Added user-space interface for crypto_rng. - Misc fixes" * git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6: (71 commits) crypto: tcrypt - do not allocate iv on stack for aead speed tests crypto: testmgr - limit IV copy length in aead tests crypto: tcrypt - fix buflen reminder calculation crypto: testmgr - mark rfc4106(gcm(aes)) as fips_allowed crypto: caam - fix resource clean-up on error path for caam_jr_init crypto: caam - pair irq map and dispose in the same function crypto: ccp - terminate ccp_support array with empty element crypto: caam - remove unused local variable crypto: caam - remove dead code crypto: caam - don't emit ICV check failures to dmesg hwrng: virtio - drop extra empty line crypto: replace scatterwalk_sg_next with sg_next crypto: atmel - Free memory in error path crypto: doc - remove colons in comments crypto: seqiv - Ensure that IV size is at least 8 bytes crypto: cts - Weed out non-CBC algorithms MAINTAINERS: add linux-crypto to hw random crypto: cts - Remove bogus use of seqiv crypto: qat - don't need qat_auth_state struct crypto: algif_rng - fix sparse non static symbol warning ...
2015-02-13Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvmLinus Torvalds1-0/+1
Pull KVM update from Paolo Bonzini: "Fairly small update, but there are some interesting new features. Common: Optional support for adding a small amount of polling on each HLT instruction executed in the guest (or equivalent for other architectures). This can improve latency up to 50% on some scenarios (e.g. O_DSYNC writes or TCP_RR netperf tests). This also has to be enabled manually for now, but the plan is to auto-tune this in the future. ARM/ARM64: The highlights are support for GICv3 emulation and dirty page tracking s390: Several optimizations and bugfixes. Also a first: a feature exposed by KVM (UUID and long guest name in /proc/sysinfo) before it is available in IBM's hypervisor! :) MIPS: Bugfixes. x86: Support for PML (page modification logging, a new feature in Broadwell Xeons that speeds up dirty page tracking), nested virtualization improvements (nested APICv---a nice optimization), usual round of emulation fixes. There is also a new option to reduce latency of the TSC deadline timer in the guest; this needs to be tuned manually. Some commits are common between this pull and Catalin's; I see you have already included his tree. Powerpc: Nothing yet. The KVM/PPC changes will come in through the PPC maintainers, because I haven't received them yet and I might end up being offline for some part of next week" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (130 commits) KVM: ia64: drop kvm.h from installed user headers KVM: x86: fix build with !CONFIG_SMP KVM: x86: emulate: correct page fault error code for NoWrite instructions KVM: Disable compat ioctl for s390 KVM: s390: add cpu model support KVM: s390: use facilities and cpu_id per KVM KVM: s390/CPACF: Choose crypto control block format s390/kernel: Update /proc/sysinfo file with Extended Name and UUID KVM: s390: reenable LPP facility KVM: s390: floating irqs: fix user triggerable endless loop kvm: add halt_poll_ns module parameter kvm: remove KVM_MMIO_SIZE KVM: MIPS: Don't leak FPU/DSP to guest KVM: MIPS: Disable HTW while in guest KVM: nVMX: Enable nested posted interrupt processing KVM: nVMX: Enable nested virtual interrupt delivery KVM: nVMX: Enable nested apic register virtualization KVM: nVMX: Make nested control MSRs per-cpu KVM: nVMX: Enable nested virtualize x2apic mode KVM: nVMX: Prepare for using hardware MSR bitmap ...
2015-02-13all arches, signal: move restart_block to struct task_structAndy Lutomirski1-4/+0
If an attacker can cause a controlled kernel stack overflow, overwriting the restart block is a very juicy exploit target. This is because the restart_block is held in the same memory allocation as the kernel stack. Moving the restart block to struct task_struct prevents this exploit by making the restart_block harder to locate. Note that there are other fields in thread_info that are also easy targets, at least on some architectures. It's also a decent simplification, since the restart code is more or less identical on all architectures. [james.hogan@imgtec.com: metag: align thread_info::supervisor_stack] Signed-off-by: Andy Lutomirski <luto@amacapital.net> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: David Miller <davem@davemloft.net> Acked-by: Richard Weinberger <richard@nod.at> Cc: Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Matt Turner <mattst88@gmail.com> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Haavard Skinnemoen <hskinnemoen@gmail.com> Cc: Hans-Christian Egtvedt <egtvedt@samfundet.no> Cc: Steven Miao <realmz6@gmail.com> Cc: Mark Salter <msalter@redhat.com> Cc: Aurelien Jacquiot <a-jacquiot@ti.com> Cc: Mikael Starvik <starvik@axis.com> Cc: Jesper Nilsson <jesper.nilsson@axis.com> Cc: David Howells <dhowells@redhat.com> Cc: Richard Kuo <rkuo@codeaurora.org> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Michal Simek <monstr@monstr.eu> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Jonas Bonn <jonas@southpole.se> Cc: "James E.J. Bottomley" <jejb@parisc-linux.org> Cc: Helge Deller <deller@gmx.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc) Tested-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc) Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Chen Liqin <liqin.linux@gmail.com> Cc: Lennox Wu <lennox.wu@gmail.com> Cc: Chris Metcalf <cmetcalf@ezchip.com> Cc: Guan Xuetao <gxt@mprc.pku.edu.cn> Cc: Chris Zankel <chris@zankel.net> Cc: Max Filippov <jcmvbkbc@gmail.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Guenter Roeck <linux@roeck-us.net> Signed-off-by: James Hogan <james.hogan@imgtec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-02-12MIPS,prctl: add PR_[GS]ET_FP_MODE prctl options for MIPSPaul Burton3-0/+16
Userland code may be built using an ABI which permits linking to objects that have more restrictive floating point requirements. For example, userland code may be built to target the O32 FPXX ABI. Such code may be linked with other FPXX code, or code built for either one of the more restrictive FP32 or FP64. When linking with more restrictive code, the overall requirement of the process becomes that of the more restrictive code. The kernel has no way to know in advance which mode the process will need to be executed in, and indeed it may need to change during execution. The dynamic loader is the only code which will know the overall required mode, and so it needs to have a means to instruct the kernel to switch the FP mode of the process. This patch introduces 2 new options to the prctl syscall which provide such a capability. The FP mode of the process is represented as a simple bitmask combining a number of mode bits mirroring those present in the hardware. Userland can either retrieve the current FP mode of the process: mode = prctl(PR_GET_FP_MODE); or modify the current FP mode of the process: err = prctl(PR_SET_FP_MODE, new_mode); Signed-off-by: Paul Burton <paul.burton@imgtec.com> Cc: Matthew Fortune <matthew.fortune@imgtec.com> Cc: Markos Chandras <markos.chandras@imgtec.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/8899/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2015-02-12mm: make FIRST_USER_ADDRESS unsigned long on all archsKirill A. Shutemov1-1/+1
LKP has triggered a compiler warning after my recent patch "mm: account pmd page tables to the process": mm/mmap.c: In function 'exit_mmap': >> mm/mmap.c:2857:2: warning: right shift count >= width of type [enabled by default] The code: > 2857 WARN_ON(mm_nr_pmds(mm) > 2858 round_up(FIRST_USER_ADDRESS, PUD_SIZE) >> PUD_SHIFT); In this, on tile, we have FIRST_USER_ADDRESS defined as 0. round_up() has the same type -- int. PUD_SHIFT. I think the best way to fix it is to define FIRST_USER_ADDRESS as unsigned long. On every arch for consistency. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reported-by: Wu Fengguang <fengguang.wu@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-02-11mips: drop _PAGE_FILE and pte_file()-related helpersKirill A. Shutemov4-56/+0
We've replaced remap_file_pages(2) implementation with emulation. Nobody creates non-linear mapping anymore. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Ralf Baechle <ralf@linux-mips.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-02-06kvm: add halt_poll_ns module parameterPaolo Bonzini1-0/+1
This patch introduces a new module parameter for the KVM module; when it is present, KVM attempts a bit of polling on every HLT before scheduling itself out via kvm_vcpu_block. This parameter helps a lot for latency-bound workloads---in particular I tested it with O_DSYNC writes with a battery-backed disk in the host. In this case, writes are fast (because the data doesn't have to go all the way to the platters) but they cannot be merged by either the host or the guest. KVM's performance here is usually around 30% of bare metal, or 50% if you use cache=directsync or cache=writethrough (these parameters avoid that the guest sends pointless flush requests, and at the same time they are not slow because of the battery-backed cache). The bad performance happens because on every halt the host CPU decides to halt itself too. When the interrupt comes, the vCPU thread is then migrated to a new physical CPU, and in general the latency is horrible because the vCPU thread has to be scheduled back in. With this patch performance reaches 60-65% of bare metal and, more important, 99% of what you get if you use idle=poll in the guest. This means that the tunable gets rid of this particular bottleneck, and more work can be done to improve performance in the kernel or QEMU. Of course there is some price to pay; every time an otherwise idle vCPUs is interrupted by an interrupt, it will poll unnecessarily and thus impose a little load on the host. The above results were obtained with a mostly random value of the parameter (500000), and the load was around 1.5-2.5% CPU usage on one of the host's core for each idle guest vCPU. The patch also adds a new stat, /sys/kernel/debug/kvm/halt_successful_poll, that can be used to tune the parameter. It counts how many HLT instructions received an interrupt during the polling period; each successful poll avoids that Linux schedules the VCPU thread out and back in, and may also avoid a likely trip to C1 and back for the physical CPU. While the VM is idle, a Linux 4 VCPU VM halts around 10 times per second. Of these halts, almost all are failed polls. During the benchmark, instead, basically all halts end within the polling period, except a more or less constant stream of 50 per second coming from vCPUs that are not running the benchmark. The wasted time is thus very low. Things may be slightly different for Windows VMs, which have a ~10 ms timer tick. The effect is also visible on Marcelo's recently-introduced latency test for the TSC deadline timer. Though of course a non-RT kernel has awful latency bounds, the latency of the timer is around 8000-10000 clock cycles compared to 20000-120000 without setting halt_poll_ns. For the TSC deadline timer, thus, the effect is both a smaller average latency and a smaller variance. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-02-04MIPS: Fix syscall_get_nr for the syscall exit tracing.Lars Persson2-7/+2
Register 2 is alredy overwritten by the return value when syscall_trace_leave() is called. Signed-off-by: Lars Persson <larper@axis.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/9187/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2015-02-02mtd: nand: jz4740: Convert to GPIO descriptor APILars-Peter Clausen1-2/+0
Use the GPIO descriptor API instead of the deprecated legacy GPIO API to manage the busy GPIO. The patch updates both the jz4740 nand driver and the only user of the driver the qi-lb60 board driver. Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Acked-by: Ralf Baechle <ralf@linux-mips.org> Signed-off-by: Brian Norris <computersforpeace@gmail.com>
2015-01-31MIPS: mipsregs.h: Add write_32bit_cp1_register()James Hogan1-0/+15
Add a write_32bit_cp1_register() macro to compliment the read_32bit_cp1_register() macro. This is to abstract whether .set hardfloat needs to be used based on GAS_HAS_SET_HARDFLOAT. The implementation of _read_32bit_cp1_register() .sets mips1 due to failure of gas v2.19 to assemble cfc1 for Octeon (see commit 25c300030016 ("MIPS: Override assembler target architecture for octeon.")). I haven't copied this over to _write_32bit_cp1_register() as I'm uncertain whether it applies to ctc1 too, or whether anybody cares about that version of binutils any longer. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Burton <paul.burton@imgtec.com> Cc: David Daney <david.daney@cavium.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/9172/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2015-01-19MIPS: ARC: Fix build error.Ralf Baechle1-3/+3
[...] struct component { ^ In file included from ./arch/mips/include/asm/sn/klconfig.h:58:0, from ./arch/mips/include/asm/sn/module.h:12, from ./arch/mips/include/asm/sn/node.h:8, from ./arch/mips/include/asm/mach-ip35/mmzone.h:4, from ./arch/mips/include/asm/mmzone.h:9, from ./arch/mips/include/asm/mach-ip35/topology.h:7, from ./arch/mips/include/asm/topology.h:11, from include/linux/topology.h:35, from include/linux/gfp.h:8, from include/linux/device.h:29, from drivers/base/component.c:14: ./arch/mips/include/asm/fw/arc/hinv.h:122:16: note: originally defined here typedef struct component { ^ make[2]: *** [drivers/base/component.o] Error 1 make[2]: Target `__build' not remade because of errors. make[1]: *** [drivers/base] Error 2 make[1]: Target `__build' not remade because of errors. Fix by using an nameless struct definition in the COMPONENT definition. Which is what the ARC spec uses anyway. While at it, do the same thing for two other typedefs. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2015-01-16MIPS: Remove unused dt_setup_arch()Geert Uytterhoeven1-7/+0
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/8928/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2015-01-13MIPS: ARC: Add declarations for a few missing ARC firmware functions.Ralf Baechle1-0/+3
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2015-01-13MIPS: ARC: Use __noreturn instead of open coded attributes in declarations.Ralf Baechle1-2/+3
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2015-01-13MIPS: Use generic csum_tcpudp_magic for MIPS.Ralf Baechle1-13/+0
Its implementation is identical to MIPS. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2015-01-13MIPS: Use <asm-generic/checksum.h>Ralf Baechle1-0/+7
Right now the MIPS <asm/checksum.h> still overrides all functions. This will change in the future. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>