kernel/git/stable/linux.git/arch/mips/mm, branch linux-4.12.y

MIPS: Perform post-DMA cache flushes on systems with MAARs

2017-06-30T02:40:46+00:00

Recent CPUs from Imagination Technologies such as the I6400 or P6600 are able to speculatively fetch data from memory into caches. This means that if used in a system with non-coherent DMA they require that caches be invalidated after a device performs DMA, and before the CPU reads the DMA'd data, in order to ensure that stale values weren't speculatively prefetched. Such CPUs also introduced Memory Accessibility Attribute Registers (MAARs) in order to control the regions in which they are allowed to speculate. Thus we can use the presence of MAARs as a good indication that the CPU requires the above cache maintenance. Use the presence of MAARs to determine the result of cpu_needs_post_dma_flush() in the default case, in order to handle these recent CPUs correctly. Note that the return type of cpu_needs_post_dma_flush() is changed to bool, such that it's clearer what's happening when cpu_has_maar is cast to bool for the return value. If this patch were backported to a pre-v4.7 kernel then MIPS_CPU_MAAR was 1ull<<34, so when cast to an int we would incorrectly return 0. It so happens that MIPS_CPU_MAAR is currently 1ull<<30, so when truncated to an int gives a non-zero value anyway, but even so the implicit conversion from long long int to bool makes it clearer to understand what will happen than the implicit conversion from long long int to int would. The bool return type also fits this usage better semantically, so seems like an all-round win. Thanks to Ed for spotting the issue for pre-v4.7 kernels & suggesting the return type change. Signed-off-by: Paul Burton Reviewed-by: Bryan O'Donoghue Tested-by: Bryan O'Donoghue Cc: Ed Blake Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/16363/ Signed-off-by: Ralf Baechle

mm: larger stack guard gap, between vmas

2017-06-19T13:50:20+00:00

Stack guard page is a useful feature to reduce a risk of stack smashing into a different mapping. We have been using a single page gap which is sufficient to prevent having stack adjacent to a different mapping. But this seems to be insufficient in the light of the stack usage in userspace. E.g. glibc uses as large as 64kB alloca() in many commonly used functions. Others use constructs liks gid_t buffer[NGROUPS_MAX] which is 256kB or stack strings with MAX_ARG_STRLEN. This will become especially dangerous for suid binaries and the default no limit for the stack size limit because those applications can be tricked to consume a large portion of the stack and a single glibc call could jump over the guard page. These attacks are not theoretical, unfortunatelly. Make those attacks less probable by increasing the stack guard gap to 1MB (on systems with 4k pages; but make it depend on the page size because systems with larger base pages might cap stack allocations in the PAGE_SIZE units) which should cover larger alloca() and VLA stack allocations. It is obviously not a full fix because the problem is somehow inherent, but it should reduce attack space a lot. One could argue that the gap size should be configurable from userspace, but that can be done later when somebody finds that the new 1MB is wrong for some special case applications. For now, add a kernel command line option (stack_guard_gap) to specify the stack gap size (in page units). Implementation wise, first delete all the old code for stack guard page: because although we could get away with accounting one extra page in a stack vma, accounting a larger gap can break userspace - case in point, a program run with "ulimit -S -v 20000" failed when the 1MB gap was counted for RLIMIT_AS; similar problems could come with RLIMIT_MLOCK and strict non-overcommit mode. Instead of keeping gap inside the stack vma, maintain the stack guard gap as a gap between vmas: using vm_start_gap() in place of vm_start (or vm_end_gap() in place of vm_end if VM_GROWSUP) in just those few places which need to respect the gap - mainly arch_get_unmapped_area(), and and the vma tree's subtree_gap support for that. Original-patch-by: Oleg Nesterov Original-patch-by: Michal Hocko Signed-off-by: Hugh Dickins Acked-by: Michal Hocko Tested-by: Helge Deller # parisc Signed-off-by: Linus Torvalds

MIPS: mm: fixed mappings: correct initialisation

2017-06-08T12:51:58+00:00

fixrange_init operates at PMD-granularity and expects the addresses to be PMD-size aligned, but currently that might not be the case for PKMAP_BASE unless it is defined properly, so ensure a correct alignment is used before passing the address to fixrange_init. fixed mappings: only align the start address that is passed to fixrange_init rather than the value before adding the size, as we may end up with uninitialised upper part of the range. Signed-off-by: Marcin Nowakowski Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/15948/ Signed-off-by: Ralf Baechle

Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus

2017-05-12T16:56:30+00:00

Pull MIPS updates from James Hogan: "math-emu: - Add missing clearing of BLTZALL and BGEZALL emulation counters - Fix BC1EQZ and BC1NEZ condition handling - Fix BLEZL and BGTZL identification BPF: - Add JIT support for SKF_AD_HATYPE - Use unsigned access for unsigned SKB fields - Quit clobbering callee saved registers in JIT code - Fix multiple problems in JIT skb access helpers Loongson 3: - Select MIPS_L1_CACHE_SHIFT_6 Octeon: - Remove vestiges of CONFIG_CAVIUM_OCTEON_2ND_KERNEL - Remove unused L2C types and macros. - Remove unused SLI types and macros. - Fix compile error when USB is not enabled. - Octeon: Remove unused PCIERCX types and macros. - Octeon: Clean up platform code. SNI: - Remove recursive include of cpu-feature-overrides.h Sibyte: - Export symbol periph_rev to sb1250-mac network driver. - Fix Kconfig warning. Generic platform: - Enable Root FS on NFS in generic_defconfig SMP-MT: - Use CPU interrupt controller IPI IRQ domain support UASM: - Add support for LHU for uasm. - Remove needless ISA abstraction mm: - Add 48-bit VA space and 4-level page tables for 4K pages. PCI: - Add controllers before the specified head irqchip driver for MIPS CPU: - Replace magic 0x100 with IE_SW0 - Prepare for non-legacy IRQ domains - Introduce IPI IRQ domain support MAINTAINERS: - Update email-id of Rahul Bedarkar NET: - sb1250-mac: Add missing MODULE_LICENSE() CPUFREQ: - Loongson2: drop set_cpus_allowed_ptr() Misc: - Disable Werror when W= is set - Opt into HAVE_COPY_THREAD_TLS - Enable GENERIC_CPU_AUTOPROBE - Use common outgoing-CPU-notification code - Remove dead define of ST_OFF - Remove CONFIG_ARCH_HAS_ILOG2_U{32,64} - Stengthen IPI IRQ domain sanity check - Remove confusing else statement in __do_page_fault() - Don't unnecessarily include kmalloc.h into . - Delete unused definition of SMP_CACHE_SHIFT. - Delete redundant definition of SMP_CACHE_BYTES" * 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus: (39 commits) MIPS: Sibyte: Fix Kconfig warning. MIPS: Sibyte: Export symbol periph_rev to sb1250-mac network driver. NET: sb1250-mac: Add missing MODULE_LICENSE() MAINTAINERS: Update email-id of Rahul Bedarkar MIPS: Remove confusing else statement in __do_page_fault() MIPS: Stengthen IPI IRQ domain sanity check MIPS: smp-mt: Use CPU interrupt controller IPI IRQ domain support irqchip: mips-cpu: Introduce IPI IRQ domain support irqchip: mips-cpu: Prepare for non-legacy IRQ domains irqchip: mips-cpu: Replace magic 0x100 with IE_SW0 MIPS: Remove CONFIG_ARCH_HAS_ILOG2_U{32,64} MIPS: generic: Enable Root FS on NFS in generic_defconfig MIPS: mach-rm: Remove recursive include of cpu-feature-overrides.h MIPS: Opt into HAVE_COPY_THREAD_TLS CPUFREQ: Loongson2: drop set_cpus_allowed_ptr() MIPS: uasm: Remove needless ISA abstraction MIPS: Remove dead define of ST_OFF MIPS: Use common outgoing-CPU-notification code MIPS: math-emu: Fix BC1EQZ and BC1NEZ condition handling MIPS: r2-on-r6-emu: Clear BLTZALL and BGEZALL debugfs counters ...

Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

2017-05-08T19:37:56+00:00

Pull KVM updates from Paolo Bonzini: "ARM: - HYP mode stub supports kexec/kdump on 32-bit - improved PMU support - virtual interrupt controller performance improvements - support for userspace virtual interrupt controller (slower, but necessary for KVM on the weird Broadcom SoCs used by the Raspberry Pi 3) MIPS: - basic support for hardware virtualization (ImgTec P5600/P6600/I6400 and Cavium Octeon III) PPC: - in-kernel acceleration for VFIO s390: - support for guests without storage keys - adapter interruption suppression x86: - usual range of nVMX improvements, notably nested EPT support for accessed and dirty bits - emulation of CPL3 CPUID faulting generic: - first part of VCPU thread request API - kvm_stat improvements" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (227 commits) kvm: nVMX: Don't validate disabled secondary controls KVM: put back #ifndef CONFIG_S390 around kvm_vcpu_kick Revert "KVM: Support vCPU-based gfn->hva cache" tools/kvm: fix top level makefile KVM: x86: don't hold kvm->lock in KVM_SET_GSI_ROUTING KVM: Documentation: remove VM mmap documentation kvm: nVMX: Remove superfluous VMX instruction fault checks KVM: x86: fix emulation of RSM and IRET instructions KVM: mark requests that need synchronization KVM: return if kvm_vcpu_wake_up() did wake up the VCPU KVM: add explicit barrier to kvm_vcpu_kick KVM: perform a wake_up in kvm_make_all_cpus_request KVM: mark requests that do not need a wakeup KVM: remove #ifndef CONFIG_S390 around kvm_vcpu_wake_up KVM: x86: always use kvm_make_request instead of set_bit KVM: add kvm_{test,clear}_request to replace {test,clear}_bit s390: kvm: Cpu model support for msa6, msa7 and msa8 KVM: x86: remove irq disablement around KVM_SET_CLOCK/KVM_GET_CLOCK kvm: better MWAIT emulation for guests KVM: x86: virtualize cpuid faulting ...

MIPS: Remove confusing else statement in __do_page_fault()

2017-04-12T22:47:04+00:00

Commit 41c594ab65fc ("[MIPS] MT: Improved multithreading support.") added an else case to an if statement in do_page_fault() (which has since gained 2 leading underscores) for some unclear reason. If the condition in the if statement evaluates true then we execute a goto & branch elsewhere anyway, so the else has no effect. Combined with an #if 0 block with misleading indentation introduced in the same commit it makes the code less clear than it could be. Remove the unnecessary else statement & de-indent the printk within the #if 0 block in order to make the code easier for humans to parse. Signed-off-by: Paul Burton Cc: linux-mips@linux-mips.org Cc: trivial@kernel.org Patchwork: https://patchwork.linux-mips.org/patch/15842/ Signed-off-by: Ralf Baechle

MIPS: uasm: Remove needless ISA abstraction

2017-04-12T11:52:21+00:00

We always either target MIPS32/MIPS64 or microMIPS, and always include one & only one of uasm-mips.c or uasm-micromips.c. Therefore the abstraction of the ISA in asm/uasm.h declaring functions for either ISA is redundant & needless. Remove it to simplify the code. This is largely the result of the following: :%s/ISAOPC(\(.\{-}\))/uasm_i##\1/ :%s/ISAFUNC(\(.\{-}\))/\1/ Signed-off-by: Paul Burton Cc: linux-mips@linux-mips.org Cc: Paul Burton Patchwork: https://patchwork.linux-mips.org/patch/15844/ Signed-off-by: Ralf Baechle

MIPS: Add 48-bit VA space (and 4-level page tables) for 4K pages.

2017-04-10T09:56:06+00:00

Some users must have 4K pages while needing a 48-bit VA space size. The cleanest way do do this is to go to a 4-level page table for this case. Each page table level using order-0 pages adds 9 bits to the VA size (at 4K pages, so for four levels we get 9 * 4 + 12 == 48-bits. For the 4K page size case only we add support functions for the PUD level of the page table tree, also the TLB exception handlers get an extra level of tree walk. [david.daney@cavium.com: Forward port to v4.10.] [david.daney@cavium.com: Forward port to v4.11.] Signed-off-by: Alex Belits Signed-off-by: David Daney Cc: James Hogan Cc: Alex Belits Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/15312/ Signed-off-by: Ralf Baechle

MIPS: uasm: Add support for LHU.

2017-04-10T09:56:04+00:00

The follow-on BPF JIT patches use the LHU instruction, so add it. Signed-off-by: David Daney Cc: James Hogan Cc: Alexei Starovoitov Cc: Steven J. Hill Cc: linux-mips@linux-mips.org Cc: netdev@vger.kernel.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/15743/ Signed-off-by: Ralf Baechle

KVM: MIPS/Emulate: Adapt T&E CACHE emulation for Octeon

2017-03-28T14:36:17+00:00

Cache management is implemented separately for Cavium Octeon CPUs, so r4k_blast_[id]cache aren't available. Instead for Octeon perform a local icache flush using local_flush_icache_range(), and for other platforms which don't use c-r4k.c use __flush_cache_all() / flush_icache_all(). Signed-off-by: James Hogan Cc: Paolo Bonzini Cc: "Radim Krčmář" Cc: Ralf Baechle Cc: David Daney Cc: Andreas Herrmann Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org