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2016-07-29MIPS: c-r4k: Use SMP calls for CM indexed cache opsJames Hogan1-1/+1
The MIPS Coherence Manager (CM) can propagate address-based ("hit") cache operations to other cores in the coherent system, alleviating software of the need to use SMP calls, however indexed cache operations are not propagated by hardware since doing so makes no sense for separate caches. Update r4k_op_needs_ipi() to report that only hit cache operations are globalized by the CM, requiring indexed cache operations to be globalized by software via an SMP call. r4k_on_each_cpu() previously had a special case for CONFIG_MIPS_MT_SMP, intended to avoid the SMP calls when the only other CPUs in the system were other VPEs in the same core, and hence sharing the same caches. This was changed by commit cccf34e9411c ("MIPS: c-r4k: Fix cache flushing for MT cores") to apparently handle multi-core multi-VPE systems, but it focussed mainly on hit cache ops, so the SMP calls were still disabled entirely for CM systems. This doesn't normally cause problems, but tests can be written to hit these corner cases by using multiple threads, or changing task affinities to force the process to migrate cores. For example the failure of mprotect RW->RX to globally sync icaches (via flush_cache_range) can be detected by modifying and mprotecting a code page on one core, and migrating to a different core to execute from it. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paul Burton <paul.burton@imgtec.com> Cc: Leonid Yegoshin <leonid.yegoshin@imgtec.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/13807/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2016-07-29MIPS: c-r4k: Avoid small flush_icache_range SMP callsJames Hogan1-0/+21
Avoid SMP calls for flushing small icache ranges. On non-CM platforms, and CM platforms too after we make r4k_on_each_cpu() take the cache op type into account, it will be called on multiple CPUs due to the possibility that local_r4k_flush_icache_range_ipi() could do non-globalized indexed cache ops. This rougly copies the range size check out into r4k_flush_icache_range(), which can disallow indexed cache ops and allow r4k_on_each_cpu() to skip the SMP call. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paul Burton <paul.burton@imgtec.com> Cc: Leonid Yegoshin <leonid.yegoshin@imgtec.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/13805/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2016-07-29MIPS: c-r4k: Local flush_icache_range cache op overrideJames Hogan1-6/+18
Allow the permitted cache op types used by local_r4k_flush_icache_range_ipi() to be overridden by the SMP caller. This will allow SMP calls to be avoided under certain circumstances, falling back to a single CPU performing globalized hit cache ops only. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paul Burton <paul.burton@imgtec.com> Cc: Leonid Yegoshin <leonid.yegoshin@imgtec.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/13803/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2016-07-29MIPS: c-r4k: Split r4k_flush_kernel_vmap_range()James Hogan1-8/+17
Split the operation of r4k_flush_kernel_vmap_range() into separate SMP callbacks for the indexed cache flush and hit cache flush cases, since the logic to determine which to use can be determined by the initiating CPU prior to doing any SMP calls. This will help when we change r4k_on_each_cpu() to distinguish indexed and hit cache ops in a later patch, preventing globalized hit cache ops being performed redundantly on multiple CPUs. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paul Burton <paul.burton@imgtec.com> Cc: Leonid Yegoshin <leonid.yegoshin@imgtec.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/13806/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2016-07-29MIPS: c-r4k: Exclude sibling CPUs in SMP callsJames Hogan1-4/+13
When performing SMP calls to foreign cores, exclude sibling CPUs from the provided map, as we already handle the local core on the current CPU. This prevents an SMP call from for example core 0, VPE 1 to VPE 0 on the same core. In the process the cpu_foreign_map cpumask is turned into an array of cpumasks, so that each CPU has its own version of it which excludes sibling CPUs. r4k_op_needs_ipi() is also updated to reflect that cache management SMP calls are not needed when all CPUs are siblings (i.e. there are no foreign CPUs according to the new cpu_foreign_map[] semantics which exclude siblings). Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paul Burton <paul.burton@imgtec.com> Cc: Leonid Yegoshin <leonid.yegoshin@imgtec.com> Cc: Felix Fietkau <nbd@nbd.name> Cc: Jayachandran C. <jchandra@broadcom.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/13801/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2016-07-29MIPS: c-r4k: Fix valid ASID optimisationJames Hogan1-13/+35
Several cache operations are optimised to return early from the SMP call handler if the memory map in question has no valid ASID on the current CPU, or any online CPU in the case of MIPS_MT_SMP. The idea is that if a memory map has never been used on a CPU it shouldn't have cache lines in need of flushing. However this doesn't cover all cases when ASIDs for other CPUs need to be checked: - Offline VPEs may have recently been online and brought lines into the (shared) cache, so they should also be checked, rather than only online CPUs. - SMP systems with a Coherence Manager (CM), but with MT disabled still have globalized hit cache ops, but don't use SMP calls, so all present CPUs should be taken into account. - R6 systems have a different multithreading implementation, so MIPS_MT_SMP won't be set, but as above may still have a CM which globalizes hit cache ops. Additionally for non-globalized cache operations where an SMP call to a single VPE in each foreign core is used, it is not necessary to check every CPU in the system, only sibling CPUs sharing the same first level cache. Fix this by making has_valid_asid() take a cache op type argument like r4k_on_each_cpu(), so it can determine whether r4k_on_each_cpu() will have done SMP calls to other cores. It can then determine which set of CPUs to check the ASIDs of based on that, excluding foreign CPUs if an SMP call will have been performed. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paul Burton <paul.burton@imgtec.com> Cc: Leonid Yegoshin <leonid.yegoshin@imgtec.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/13804/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2016-07-29MIPS: c-r4k: Add r4k_on_each_cpu cache op type argJames Hogan1-19/+51
The r4k_on_each_cpu() function calls the specified cache flush helper on other CPUs if deemed necessary due to the cache ops not being globalized by hardware. However this really depends on the cache op addressing type, as the MIPS Coherence Manager (CM) if present will globalize "hit" cache ops (addressed by virtual address), but not "index" cache ops (addressed by cache index). This results in index cache ops only being performed on a single CPU when CM is present. Most (but not all) of the functions called by r4k_on_each_cpu() perform cache operations exclusively with a single cache op type, so add a type argument and modify the callers to pass in some combination of R4K_HIT (global kernel virtual addressing or user virtual addressing conditional upon matching active_mm) and R4K_INDEX (index into cache). This will allow r4k_on_each_cpu() to later distinguish these cases and decide whether to perform an SMP call based on it. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paul Burton <paul.burton@imgtec.com> Cc: Leonid Yegoshin <leonid.yegoshin@imgtec.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/13798/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2016-07-29MIPS: c-r4k: Avoid dcache flush for sigtrampsJames Hogan1-6/+10
Avoid the dcache and scache flush in local_r4k_flush_cache_sigtramp() if the icache fills straight from the dcache. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paul Burton <paul.burton@imgtec.com> Cc: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/13802/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2016-07-29MIPS: c-r4k: Fix sigtramp SMP call to use kmapJames Hogan1-6/+69
Fix r4k_flush_cache_sigtramp() and local_r4k_flush_cache_sigtramp() to flush the delay slot emulation trampoline cacheline through a kmap rather than directly when the active_mm doesn't match that of the task initiating the flush, a bit like local_r4k_flush_cache_page() does. This would fix a corner case on SMP systems without hardware globalized hit cache ops, where a migration to another CPU after the flush, where that CPU did not have the same mm active at the time of the flush, could result in stale icache content being executed instead of the trampoline, e.g. from a previous delay slot emulation with a similar stack pointer. This case was artificially triggered by replacing the icache flush with a full indexed flush (not globalized on CM systems) and forcing the SMP call to take place, with a test program that alternated two FPU delay slots with a parent process repeatedly changing scheduler affinity. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paul Burton <paul.burton@imgtec.com> Cc: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/13797/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2016-07-29MIPS: SMP: Clear ASID without confusing has_valid_asid()James Hogan1-0/+4
The SMP flush_tlb_*() functions may clear the memory map's ASIDs for other CPUs if the mm has only a single user (the current CPU) in order to avoid SMP calls. However this makes it appear to has_valid_asid(), which is used by various cache flush functions, as if the CPUs have never run in the mm, and therefore can't have cached any of its memory. For flush_tlb_mm() this doesn't sound unreasonable. flush_tlb_range() corresponds to flush_cache_range() which does do full indexed cache flushes, but only on the icache if the specified mapping is executable, otherwise it doesn't guarantee that there are no cache contents left for the mm. flush_tlb_page() corresponds to flush_cache_page(), which will perform address based cache ops on the specified page only, and also only touches the icache if the page is executable. It does not guarantee that there are no cache contents left for the mm. For example, this affects flush_cache_range() which uses the has_valid_asid() optimisation. It is required to flush the icache when mappings are made executable (e.g. using mprotect) so they are immediately usable. If some code is changed to non executable in order to be modified then it will not be flushed from the icache during that time, but the ASID on other CPUs may still be cleared for TLB flushing. When the code is changed back to executable, flush_cache_range() will assume the code hasn't run on those other CPUs due to the zero ASID, and won't invalidate the icache on them. This is fixed by clearing the other CPUs ASIDs to 1 instead of 0 for the above two flush_tlb_*() functions when the corresponding cache flushes are likely to be incomplete (non executable range flush, or any page flush). This ASID appears valid to has_valid_asid(), but still triggers ASID regeneration due to the upper ASID version bits being 0, which is less than the minimum ASID version of 1 and so always treated as stale. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paul Burton <paul.burton@imgtec.com> Cc: Leonid Yegoshin <leonid.yegoshin@imgtec.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/13795/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2016-07-27mm: do not pass mm_struct into handle_mm_faultKirill A. Shutemov1-1/+1
We always have vma->vm_mm around. Link: http://lkml.kernel.org/r/1466021202-61880-8-git-send-email-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-07-24MIPS: tlbex: Avoid duplicated single_insn_swpdJames Hogan1-1/+1
The expression "uasm_in_compat_space_p(swpd) && !uasm_rel_lo(swpd)" is used twice in build_get_pgd_vmalloc64(), one of which is assigned to the local variable single_insn_swpd. Update the other use to just use single_insn_swpd instead to remove the duplication. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: David Daney <ddaney@caviumnetworks.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/13779/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2016-07-24MIPS: uasm: Handle low values in uasm_in_compat_space_p()James Hogan1-5/+1
uasm_in_compat_space_p() determines whether the given value is in the 32-bit compatibility part of the 64-bit address space, i.e. is in 32-bit sign-extended form, however it only handles the top half of the value space (corresponding to the kernel compatibility segments in the upper half of the address space). Since values < 2^31 (corresponding to the low 2GiB of the address space) can also be handled using 32-bit instructions (e.g. a LUI and ADDIU) rather than convoluted 64-bit immediate generation, rewrite it with a cast to check whether the address matches its 32-bit sign extended form. This allows UASM_i_LA to be used to generate arbitrary 32-bit immediates more efficiently on 64-bit CPUs, i.e. more like the li (load immediate) pseudo-instruction. For example this code to load the immediate (ST0_EXL | KSU_USER | ST0_BEV | ST0_KX) into k0 with UASM_i_LA(): lui k0,0x0 dsll k0,k0,0x10 daddiu k0,k0,64 dsll k0,k0,0x10 daddiu k0,k0,146 Changes to this more efficient version: lui k0,0x40 addiu k0,k0,146 Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/13778/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2016-07-21MIPS: RM7000: Double locking bug in rm7k_tc_disable()Dan Carpenter1-1/+1
We obviously intended to enable IRQs again at the end. Fixes: 745aef5df1e2 ('MIPS: RM7000: Add support for tertiary cache') Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Cc: kernel-janitors@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/13815/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2016-07-06MIPS: Remove cpu_has_safe_index_cacheopsRalf Baechle1-9/+3
Very early versions of the 1004K had an hardware issue that made index cache ops unsafe so they had to be avoided and hit ops be used instead. This may significantly slow down cache maintenance operations. Only very early FPGA versions of the 1004K were affected so let's get rid of the workaround which was only implemented for the DMA cache maintenance operations anyway. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2016-07-05MIPS: uasm: Add r6 MUL encodingJames Hogan1-0/+4
Add the R6 MUL instruction encoding for 3 operand signed multiply to uasm so that KVM can use uasm for generating its entry point code at runtime on R6. Signed-off-by: James Hogan <james.hogan@imgtec.com> Acked-by: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-07-05MIPS: uasm: Add MTHI/MTLO instructionsJames Hogan3-5/+12
Add MTHI/MTLO instructions for writing to the hi & lo registers to uasm so that KVM can use uasm for generating its entry point code at runtime. Signed-off-by: James Hogan <james.hogan@imgtec.com> Acked-by: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-07-05MIPS: uasm: Add DI instructionJames Hogan3-11/+14
Add DI instruction for disabling interrupts to uasm so that KVM can use uasm for generating its entry point code at runtime. Signed-off-by: James Hogan <james.hogan@imgtec.com> Acked-by: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-07-05MIPS: uasm: Add CFCMSA/CTCMSA instructionsJames Hogan3-12/+18
Add CFCMSA/CTCMSA instructions for accessing MSA control registers to uasm so that KVM can use uasm for generating its entry point code at runtime. Signed-off-by: James Hogan <james.hogan@imgtec.com> Acked-by: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-07-05MIPS: uasm: Add CFC1/CTC1 instructionsJames Hogan3-14/+22
Add CFC1/CTC1 instructions for accessing FP control registers to uasm so that KVM can use uasm for generating its entry point code at runtime. Signed-off-by: James Hogan <james.hogan@imgtec.com> Acked-by: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-06-16MIPS: Add define for Config.VI (virtual icache) bitJames Hogan1-1/+1
The Config.VI bit specifies that the instruction cache is virtually tagged, which is checked in c-r4k.c's probe_pcache(). Add a proper definition for it in mipsregs.h and make use of it. Signed-off-by: James Hogan <james.hogan@imgtec.com> Acked-by: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-05-29Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linusLinus Torvalds1-4/+18
Pull more MIPS updates from Ralf Baechle: "This is the secondnd batch of MIPS patches for 4.7. Summary: CPS: - Copy EVA configuration when starting secondary VPs. EIC: - Clear Status IPL. Lasat: - Fix a few off by one bugs. lib: - Mark intrinsics notrace. Not only are the intrinsics uninteresting, it would cause infinite recursion. MAINTAINERS: - Add file patterns for MIPS BRCM device tree bindings. - Add file patterns for mips device tree bindings. MT7628: - Fix MT7628 pinmux typos. - wled_an pinmux gpio. - EPHY LEDs pinmux support. Pistachio: - Enable KASLR VDSO: - Build microMIPS VDSO for microMIPS kernels. - Fix aliasing warning by building with `-fno-strict-aliasing' for debugging but also tracing them might result in recursion. Misc: - Add missing FROZEN hotplug notifier transitions. - Fix clk binding example for varioius PIC32 devices. - Fix cpu interrupt controller node-names in the DT files. - Fix XPA CPU feature separation. - Fix write_gc0_* macros when writing zero. - Add inline asm encoding helpers. - Add missing VZ accessor microMIPS encodings. - Fix little endian microMIPS MSA encodings. - Add 64-bit HTW fields and fix its configuration. - Fix sigreturn via VDSO on microMIPS kernel. - Lots of typo fixes. - Add definitions of SegCtl registers and use them" * 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus: (49 commits) MIPS: Add missing FROZEN hotplug notifier transitions MIPS: Build microMIPS VDSO for microMIPS kernels MIPS: Fix sigreturn via VDSO on microMIPS kernel MIPS: devicetree: fix cpu interrupt controller node-names MIPS: VDSO: Build with `-fno-strict-aliasing' MIPS: Pistachio: Enable KASLR MIPS: lib: Mark intrinsics notrace MIPS: Fix 64-bit HTW configuration MIPS: Add 64-bit HTW fields MAINTAINERS: Add file patterns for mips device tree bindings MAINTAINERS: Add file patterns for mips brcm device tree bindings MIPS: Simplify DSP instruction encoding macros MIPS: Add missing tlbinvf/XPA microMIPS encodings MIPS: Fix little endian microMIPS MSA encodings MIPS: Add missing VZ accessor microMIPS encodings MIPS: Add inline asm encoding helpers MIPS: Spelling fix lets -> let's MIPS: VR41xx: Fix typo MIPS: oprofile: Fix typo MIPS: math-emu: Fix typo ...
2016-05-28MIPS: Fix 64-bit HTW configurationJames Hogan1-2/+12
The Hardware page Table Walker (HTW) is being misconfigured on 64-bit kernels. The PWSize.PS (pointer size) bit determines whether pointers within directories are loaded as 32-bit or 64-bit addresses, but was never being set to 1 for 64-bit kernels where the unsigned long in pgd_t is 64-bits wide. This actually reduces rather than improves performance when the HTW is enabled on P6600 since the HTW is initiated lots, but walks are all aborted due I think to bad intermediate pointers. Since we were already taking the width of the PTEs into account by setting PWSize.PTEW, which is the left shift applied to the page table index *in addition to* the native pointer size, we also need to reduce PTEW by 1 when PS=1. This is done by calculating PTEW based on the relative size of pte_t compared to pgd_t. Finally in order for the HTW to be used when PS=1, the appropriate XK/XS/XU bits corresponding to the different 64-bit segments need to be set in PWCtl. We enable only XU for now to enable walking for XUSeg. Supporting walking for XKSeg would be a bit more involved so is left for a future patch. It would either require the use of a per-CPU top level base directory if supported by the HTW (a bit like pgd_current but with a second entry pointing at swapper_pg_dir), or the HTW would prepend bit 63 of the address to the global directory index which doesn't really match how we split user and kernel page directories. Fixes: cab25bc7537b ("MIPS: Extend hardware table walking support to MIPS64") Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paul Burton <paul.burton@imgtec.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/13364/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2016-05-28MIPS: Add 64-bit HTW fieldsJames Hogan1-2/+6
Add field definitions for some of the 64-bit specific Hardware page Table Walker (HTW) register fields in PWSize and PWCtl, in preparation for fixing the 64-bit HTW configuration. Also print these fields out along with the others in print_htw_config(). Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paul Burton <paul.burton@imgtec.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/13363/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2016-05-20Merge branch 'akpm' (patches from Andrew)Linus Torvalds1-10/+11
Merge updates from Andrew Morton: - fsnotify fix - poll() timeout fix - a few scripts/ tweaks - debugobjects updates - the (small) ocfs2 queue - Minor fixes to kernel/padata.c - Maybe half of the MM queue * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (117 commits) mm, page_alloc: restore the original nodemask if the fast path allocation failed mm, page_alloc: uninline the bad page part of check_new_page() mm, page_alloc: don't duplicate code in free_pcp_prepare mm, page_alloc: defer debugging checks of pages allocated from the PCP mm, page_alloc: defer debugging checks of freed pages until a PCP drain cpuset: use static key better and convert to new API mm, page_alloc: inline pageblock lookup in page free fast paths mm, page_alloc: remove unnecessary variable from free_pcppages_bulk mm, page_alloc: pull out side effects from free_pages_check mm, page_alloc: un-inline the bad part of free_pages_check mm, page_alloc: check multiple page fields with a single branch mm, page_alloc: remove field from alloc_context mm, page_alloc: avoid looking up the first zone in a zonelist twice mm, page_alloc: shortcut watermark checks for order-0 pages mm, page_alloc: reduce cost of fair zone allocation policy retry mm, page_alloc: shorten the page allocator fast path mm, page_alloc: check once if a zone has isolated pageblocks mm, page_alloc: move __GFP_HARDWALL modifications out of the fastpath mm, page_alloc: simplify last cpupid reset mm, page_alloc: remove unnecessary initialisation from __alloc_pages_nodemask() ...
2016-05-20arch: fix has_transparent_hugepage()Hugh Dickins1-10/+11
I've just discovered that the useful-sounding has_transparent_hugepage() is actually an architecture-dependent minefield: on some arches it only builds if CONFIG_TRANSPARENT_HUGEPAGE=y, on others it's also there when not, but on some of those (arm and arm64) it then gives the wrong answer; and on mips alone it's marked __init, which would crash if called later (but so far it has not been called later). Straighten this out: make it available to all configs, with a sensible default in asm-generic/pgtable.h, removing its definitions from those arches (arc, arm, arm64, sparc, tile) which are served by the default, adding #define has_transparent_hugepage has_transparent_hugepage to those (mips, powerpc, s390, x86) which need to override the default at runtime, and removing the __init from mips (but maybe that kind of code should be avoided after init: set a static variable the first time it's called). Signed-off-by: Hugh Dickins <hughd@google.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Andres Lagar-Cavilla <andreslc@google.com> Cc: Yang Shi <yang.shi@linaro.org> Cc: Ning Qu <quning@gmail.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Acked-by: David S. Miller <davem@davemloft.net> Acked-by: Vineet Gupta <vgupta@synopsys.com> [arch/arc] Acked-by: Gerald Schaefer <gerald.schaefer@de.ibm.com> [arch/s390] Acked-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-13MIPS: mm: Panic if an XPA kernel is run without RIXIPaul Burton1-0/+3
XPA kernels hardcode for the presence of RIXI - the PTE format & its handling presume RI & XI bits. Make this dependence explicit by panicing if we run on a system that violates it. Signed-off-by: Paul Burton <paul.burton@imgtec.com> Reviewed-by: James Hogan <james.hogan@imgtec.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/13125/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2016-05-13MIPS: mm: Don't do MTHC0 if XPA not presentJames Hogan3-11/+19
Performing an MTHC0 instruction without XPA being present will trigger a reserved instruction exception, therefore conditionalise the use of this instruction when building TLB handlers (build_update_entries()), and in __update_tlb(). This allows an XPA kernel to run on non XPA hardware without that instruction implemented, just like it can run on XPA capable hardware without XPA in use (with the noxpa kernel argument) or with XPA not configured in hardware. [paul.burton@imgtec.com: - Rebase atop other TLB work. - Add "mm" to subject. - Handle the __kmap_pgprot case.] Fixes: c5b367835cfc ("MIPS: Add support for XPA.") Signed-off-by: James Hogan <james.hogan@imgtec.com> Signed-off-by: Paul Burton <paul.burton@imgtec.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: David Hildenbrand <dahi@linux.vnet.ibm.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Jerome Marchand <jmarchan@redhat.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/13124/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2016-05-13MIPS: mm: Simplify build_update_entriesPaul Burton1-21/+16
We can simplify build_update_entries by unifying the code for the 36 bit physical addressing with MIPS32 case with the general case, by using pte_off_ variables in all cases & handling the trivial _PAGE_GLOBAL_SHIFT == 0 case in build_convert_pte_to_entrylo. This leaves XPA as the only special case. Signed-off-by: Paul Burton <paul.burton@imgtec.com> Reviewed-by: James Hogan <james.hogan@imgtec.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/13123/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2016-05-13MIPS: mm: Be more explicit about PTE mode bit handlingPaul Burton1-5/+9
The XPA case in iPTE_SW or's in software mode bits to the pte_low value (which is what actually ends up in the high 32 bits of EntryLo...). It does this presuming that only bits in the upper 16 bits of the 32 bit pte_low value will be set. Make this assumption explicit with a BUG_ON. A similar assumption is made for the hardware mode bits, which are or'd in with a single ori instruction. Make that assumption explicit with a BUG_ON too. Signed-off-by: Paul Burton <paul.burton@imgtec.com> Cc: James Hogan <james.hogan@imgtec.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/13122/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2016-05-13MIPS: mm: Pass scratch register through to iPTE_SWPaul Burton1-13/+11
Rather than hardcode a scratch register for the XPA case in iPTE_SW, pass one through from the work registers allocated by the caller. This allows for the XPA path to function correctly regardless of the work registers in use. Without doing this there are cases (where KScratch registers are unavailable) in which iPTE_SW will incorrectly clobber $1 despite it already being in use for the PTE or PTE pointer. Signed-off-by: Paul Burton <paul.burton@imgtec.com> Reviewed-by: James Hogan <james.hogan@imgtec.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/13121/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2016-05-13MIPS: mm: Don't clobber $1 on XPA TLB refillJames Hogan1-14/+10
For XPA kernels build_update_entries() uses $1 (at) as a scratch register, but doesn't arrange for it to be preserved, so it will always be clobbered by the TLB refill exception. Although this register normally has a very short lifetime that doesn't cross memory accesses, TLB refills due to instruction fetches (either on a page boundary or after preemption) could clobber live data, and its easy to reproduce the clobber with a little bit of assembler code. Note that the use of a hardware page table walker will partly mask the problem, as the TLB refill handler will not always be invoked. This is fixed by avoiding the use of the extra scratch register. The pte_high parts (going into the lower half of the EntryLo registers) are loaded and manipulated separately so as to keep the PTE pointer around for the other halves (instead of storing in the scratch register), and the pte_low parts (going into the high half of the EntryLo registers) are masked with 0x00ffffff using an ext instruction (instead of loading 0x00ffffff into the scratch register and AND'ing). [paul.burton@imgtec.com: - Rebase atop other TLB work. - Use ext instead of an sll, srl sequence. - Use cpu_has_xpa instead of #ifdefs. - Modify commit subject to include "mm".] Fixes: c5b367835cfc ("MIPS: Add support for XPA.") Signed-off-by: James Hogan <james.hogan@imgtec.com> Signed-off-by: Paul Burton <paul.burton@imgtec.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: linux-kernel@vger.kernel.org Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/13120/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2016-05-13MIPS: mm: Fix MIPS32 36b physical addressing (alchemy, netlogic)Paul Burton2-13/+26
There are 2 distinct cases in which a kernel for a MIPS32 CPU (CONFIG_CPU_MIPS32=y) may use 64 bit physical addresses (CONFIG_PHYS_ADDR_T_64BIT=y): - 36 bit physical addressing as used by RMI Alchemy & Netlogic XLP/XLR CPUs. - MIPS32r5 eXtended Physical Addressing (XPA). These 2 cases are distinct in that they require different behaviour from the kernel - the EntryLo registers have different formats. Until Linux v4.1 we only supported the first case, with code conditional upon the 2 aforementioned Kconfig variables being set. Commit c5b367835cfc ("MIPS: Add support for XPA.") added support for the second case, but did so by modifying the code that existed for the first case rather than treating the 2 cases as distinct. Since the EntryLo registers have different formats this breaks the 36 bit Alchemy/XLP/XLR case. Fix this by splitting the 2 cases, with XPA cases now being conditional upon CONFIG_XPA and the non-XPA case matching the code as it existed prior to commit c5b367835cfc ("MIPS: Add support for XPA."). Signed-off-by: Paul Burton <paul.burton@imgtec.com> Reported-by: Manuel Lauss <manuel.lauss@gmail.com> Tested-by: Manuel Lauss <manuel.lauss@gmail.com> Fixes: c5b367835cfc ("MIPS: Add support for XPA.") Cc: James Hogan <james.hogan@imgtec.com> Cc: David Daney <david.daney@cavium.com> Cc: Huacai Chen <chenhc@lemote.com> Cc: Maciej W. Rozycki <macro@linux-mips.org> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Cc: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: David Hildenbrand <dahi@linux.vnet.ibm.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Alex Smith <alex.smith@imgtec.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: stable@vger.kernel.org # v4.1+ Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/13119/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2016-05-13MIPS: mm: Standardise on _PAGE_NO_READ, drop _PAGE_READPaul Burton1-9/+4
Ever since support for RI/XI was implemented by commit 6dd9344cfc41 ("MIPS: Implement Read Inhibit/eXecute Inhibit") we've had a mixture of _PAGE_READ & _PAGE_NO_READ bits. Rather than keep both around, switch away from using _PAGE_READ to determine page presence & instead invert the use to _PAGE_NO_READ. Wherever we formerly had no definition for _PAGE_NO_READ, change what was _PAGE_READ to _PAGE_NO_READ. The end result is that we consistently use _PAGE_NO_READ to determine whether a page is readable, regardless of whether RI/XI is implemented. Signed-off-by: Paul Burton <paul.burton@imgtec.com> Reviewed-by: James Hogan <james.hogan@imgtec.com> Cc: David Daney <david.daney@cavium.com> Cc: Huacai Chen <chenhc@lemote.com> Cc: Maciej W. Rozycki <macro@linux-mips.org> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Alex Smith <alex.smith@imgtec.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/13116/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2016-05-13MIPS: Fix HTW config on XPA kernel without LPA enabledJames Hogan1-3/+1
The hardware page table walker (HTW) configuration is broken on XPA kernels where XPA couldn't be enabled (either nohtw or the hardware doesn't support it). This is because the PWSize.PTEW field (PTE width) was only set to 8 bytes (an extra shift of 1) in config_htw_params() if PageGrain.ELPA (enable large physical addressing) is set. On an XPA kernel though the size of PTEs is fixed at 8 bytes regardless of whether XPA could actually be enabled. Fix the initialisation of this field based on sizeof(pte_t) instead. Fixes: c5b367835cfc ("MIPS: Add support for XPA.") Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Steven J. Hill <sjhill@realitydiluted.com> Cc: Paul Burton <paul.burton@imgtec.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/13113/ Signed-off-by: Paul Burton <paul.burton@imgtec.com> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2016-05-13MIPS: Retrieve ASID masks using function accepting struct cpuinfo_mipsPaul Burton3-12/+16
In preparation for supporting variable ASID masks, retrieve ASID masks using functions in asm/cpu-info.h which accept struct cpuinfo_mips. This will allow those functions to determine the ASID mask based upon the CPU in a later patch. This also allows for the r3k & r8k cases to be handled in Kconfig, which is arguably cleaner than the previous #ifdefs. Signed-off-by: Paul Burton <paul.burton@imgtec.com> Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Radim Krčmář <rkrcmar@redhat.com> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/13210/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2016-05-13MIPS: remove aliasing alignment if HW has antialising supportLeonid Yegoshin1-1/+1
MIPS hardware may have an antialising support and it works even page size is small. Setup a shared memory aliasing mask to page size if hardware has an antialising support. Big shared memory mask forces a disruption in page address assignment and that corrupts Android library memory handling. Signed-off-by: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com> Cc: cernekee@gmail.com Cc: paul.gortmaker@windriver.com Cc: kumba@gentoo.org Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/11516/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2016-05-13MIPS: Loongson-3: Introduce CONFIG_LOONGSON3_ENHANCEMENTHuacai Chen2-0/+11
New Loongson 3 CPU (since Loongson-3A R2, as opposed to Loongson-3A R1, Loongson-3B R1 and Loongson-3B R2) has many enhancements, such as FTLB, L1-VCache, EI/DI/Wait/Prefetch instruction, DSP/DSPv2 ASE, User Local register, Read-Inhibit/Execute-Inhibit, SFB (Store Fill Buffer), Fast TLB refill support, etc. This patch introduce a config option, CONFIG_LOONGSON3_ENHANCEMENT, to enable those enhancements which are not probed at run time. If you want a generic kernel to run on all Loongson 3 machines, please say 'N' here. If you want a high-performance kernel to run on new Loongson 3 machines only, please say 'Y' here. Some additional explanations: 1) SFB locates between core and L1 cache, it causes memory access out of order, so writel/outl (and other similar functions) need a I/O reorder barrier. 2) Loongson 3 has a bug that di instruction can not save the irqflag, so arch_local_irq_save() is modified. Since CPU_MIPSR2 is selected by CONFIG_LOONGSON3_ENHANCEMENT, generic kernel doesn't use ei/di at all. 3) CPU_HAS_PREFETCH is selected by CONFIG_LOONGSON3_ENHANCEMENT, so MIPS_CPU_PREFETCH (used by uasm) probing is also put in this patch. Signed-off-by: Huacai Chen <chenhc@lemote.com> Cc: Aurelien Jarno <aurelien@aurel32.net> Cc: Steven J . Hill <sjhill@realitydiluted.com> Cc: Fuxin Zhang <zhangfx@lemote.com> Cc: Zhangjin Wu <wuzhangjin@gmail.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/12755/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2016-05-13MIPS: Loongson-3: Fast TLB refill handlerHuacai Chen3-3/+126
Loongson-3A R2 has pwbase/pwfield/pwsize/pwctl registers in CP0 (this is very similar to HTW) and lwdir/lwpte/lddir/ldpte instructions which can be used for fast TLB refill. [ralf@linux-mips.org: Resolve conflict.] Signed-off-by: Huacai Chen <chenhc@lemote.com> Cc: Aurelien Jarno <aurelien@aurel32.net> Cc: Steven J . Hill <sjhill@realitydiluted.com> Cc: Fuxin Zhang <zhangfx@lemote.com> Cc: Zhangjin Wu <wuzhangjin@gmail.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/12754/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2016-05-13MIPS: Loongson: Invalidate special TLBs when neededHuacai Chen1-12/+15
Loongson-2 has a 4 entry itlb which is a subset of jtlb, Loongson-3 has a 4 entry itlb and a 4 entry dtlb which are subsets of jtlb. We should write diag register to invalidate itlb/dtlb when flushing jtlb because itlb/dtlb are not totally transparent to software. For Loongson-3A R2 (and newer), we should invalidate ITLB, DTLB, VTLB and FTLB before we enable/disable FTLB. Signed-off-by: Huacai Chen <chenhc@lemote.com> Cc: Aurelien Jarno <aurelien@aurel32.net> Cc: Steven J . Hill <sjhill@realitydiluted.com> Cc: Fuxin Zhang <zhangfx@lemote.com> Cc: Zhangjin Wu <wuzhangjin@gmail.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/12753/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2016-05-13MIPS: Loongson-3: Set cache flush handlers to cache_noopHuacai Chen1-0/+14
Loongson-3 maintains cache coherency by hardware, this means: 1) It's icache is coherent with dcache. 2) It's dcaches don't alias (maybe depend on PAGE_SIZE). 3) It maintains cache coherency across cores (and for DMA). So we can skip most cache flush operations by setting relevant handlers to `cache_noop' in `r4k_cache_init'. Signed-off-by: Huacai Chen <chenhc@lemote.com> Cc: Aurelien Jarno <aurelien@aurel32.net> Cc: Steven J . Hill <sjhill@realitydiluted.com> Cc: Fuxin Zhang <zhangfx@lemote.com> Cc: Zhangjin Wu <wuzhangjin@gmail.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/12752/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2016-05-13MIPS: Loongson: Add Loongson-3A R2 basic supportHuacai Chen1-0/+27
Loongson-3 CPU family: Code-name Brand-name PRId Loongson-3A R1 Loongson-3A1000 0x6305 Loongson-3A R2 Loongson-3A2000 0x6308 Loongson-3B R1 Loongson-3B1000 0x6306 Loongson-3B R2 Loongson-3B1500 0x6307 Features of R2 revision of Loongson-3A: - Primary cache includes I-Cache, D-Cache and V-Cache (Victim Cache). - I-Cache, D-Cache and V-Cache are 16-way set-associative, linesize is 64 bytes. - 64 entries of VTLB (classic TLB), 1024 entries of FTLB (8-way set-associative). - Supports DSP/DSPv2 instructions, UserLocal register and Read-Inhibit/ Execute-Inhibit. [ralf@linux-mips.org: Resolved merge conflicts.] Signed-off-by: Huacai Chen <chenhc@lemote.com> Cc: Aurelien Jarno <aurelien@aurel32.net> Cc: Steven J . Hill <sjhill@realitydiluted.com> Cc: Fuxin Zhang <zhangfx@lemote.com> Cc: Zhangjin Wu <wuzhangjin@gmail.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/12751/ Patchwork: https://patchwork.linux-mips.org/patch/13136/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2016-05-13MIPS: BMIPS: local_r4k___flush_cache_all needs to blast S-cacheFlorian Fainelli1-0/+5
local_r4k___flush_cache_all() is missing a special check for BMIPS5000 processors, we need to blast the S-cache, just like other MTI processors since we have an inclusive cache. We also need an additional __sync() to make sure this is completed. Fixes: d74b0172e4e2c ("MIPS: BMIPS: Add special cache handling in c-r4k.c") Signed-off-by: Florian Fainelli <f.fainelli@gmail.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/13012/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2016-05-13MIPS: BMIPS: Clear MIPS_CACHE_ALIASES earlierFlorian Fainelli1-2/+2
BMIPS5000 and BMIPS5200 processor have no D cache aliases, and this is properly handled by the per-CPU override added at the end of r4k_cache_init(), the problem is that the output of probe_pcache() disagrees with that, since this is too late: Primary instruction cache 32kB, VIPT, 4-way, linesize 64 bytes. Primary data cache 32kB, 4-way, VIPT, cache aliases, linesize 32 bytes With the change moved earlier, we now have a consistent output with the settings we are intending to have: Primary instruction cache 32kB, VIPT, 4-way, linesize 64 bytes. Primary data cache 32kB, 4-way, VIPT, no aliases, linesize 32 bytes Fixes: d74b0172e4e2c ("MIPS: BMIPS: Add special cache handling in c-r4k.c") Signed-off-by: Florian Fainelli <f.fainelli@gmail.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/13011/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2016-05-13MIPS: BMIPS: BMIPS5000 has I cache filing from D cacheFlorian Fainelli1-0/+4
BMIPS5000 and BMIPS52000 processors have their I-cache filling from the D-cache. Since BMIPS_GENERIC does not provide (yet) a cpu-feature-overrides.h file, this was not set anywhere, so make sure the R4K cache detection takes care of that. Fixes: d74b0172e4e2c ("MIPS: BMIPS: Add special cache handling in c-r4k.c") Signed-off-by: Florian Fainelli <f.fainelli@gmail.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/13010/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2016-05-13MIPS: Sync icache & dcache in set_pte_atPaul Burton1-16/+3
It's possible for pages to become visible prior to update_mmu_cache running if a thread within the same address space preempts the current thread or runs simultaneously on another CPU. That is, the following scenario is possible: CPU0 CPU1 write to page flush_dcache_page flush_icache_page set_pte_at map page update_mmu_cache If CPU1 maps the page in between CPU0's set_pte_at, which marks it valid & visible, and update_mmu_cache where the dcache flush occurs then CPU1s icache will fill from stale data (unless it fills from the dcache, in which case all is good, but most MIPS CPUs don't have this property). Commit 4d46a67a3eb8 ("MIPS: Fix race condition in lazy cache flushing.") attempted to fix that by performing the dcache flush in flush_icache_page such that it occurs before the set_pte_at call makes the page visible. However it has the problem that not all code that writes to pages exposed to userland call flush_icache_page. There are many callers of set_pte_at under mm/ and only 2 of them do call flush_icache_page. Thus the race window between a page becoming visible & being coherent between the icache & dcache remains open in some cases. To illustrate some of the cases, a WARN was added to __update_cache with this patch applied that triggered in cases where a page about to be flushed from the dcache was not the last page provided to flush_icache_page. That is, backtraces were obtained for cases in which the race window is left open without this patch. The 2 standout examples follow. When forking a process: [ 15.271842] [<80417630>] __update_cache+0xcc/0x188 [ 15.277274] [<80530394>] copy_page_range+0x56c/0x6ac [ 15.282861] [<8042936c>] copy_process.part.54+0xd40/0x17ac [ 15.289028] [<80429f80>] do_fork+0xe4/0x420 [ 15.293747] [<80413808>] handle_sys+0x128/0x14c When exec'ing an ELF binary: [ 14.445964] [<80417630>] __update_cache+0xcc/0x188 [ 14.451369] [<80538d88>] move_page_tables+0x414/0x498 [ 14.457075] [<8055d848>] setup_arg_pages+0x220/0x318 [ 14.462685] [<805b0f38>] load_elf_binary+0x530/0x12a0 [ 14.468374] [<8055ec3c>] search_binary_handler+0xbc/0x214 [ 14.474444] [<8055f6c0>] do_execveat_common+0x43c/0x67c [ 14.480324] [<8055f938>] do_execve+0x38/0x44 [ 14.485137] [<80413808>] handle_sys+0x128/0x14c These code paths write into a page, call flush_dcache_page then call set_pte_at without flush_icache_page inbetween. The end result is that the icache can become corrupted & userland processes may execute unexpected or invalid code, typically resulting in a reserved instruction exception, a trap or a segfault. Fix this race condition fully by performing any cache maintenance required to keep the icache & dcache in sync in set_pte_at, before the page is made valid. This has the added bonus of ensuring the cache maintenance always happens in one location, rather than being duplicated in flush_icache_page & update_mmu_cache. It also matches the way other architectures solve the same problem (see arm, ia64 & powerpc). Signed-off-by: Paul Burton <paul.burton@imgtec.com> Reported-by: Ionela Voinescu <ionela.voinescu@imgtec.com> Cc: Lars Persson <lars.persson@axis.com> Fixes: 4d46a67a3eb8 ("MIPS: Fix race condition in lazy cache flushing.") Cc: Steven J. Hill <sjhill@realitydiluted.com> Cc: David Daney <david.daney@cavium.com> Cc: Huacai Chen <chenhc@lemote.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Jerome Marchand <jmarchan@redhat.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Cc: stable <stable@vger.kernel.org> # v4.1+ Patchwork: https://patchwork.linux-mips.org/patch/12722/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2016-05-13MIPS: Handle highmem pages in __update_cachePaul Burton1-1/+9
The following patch will expose __update_cache to highmem pages. Handle them by mapping them in for the duration of the cache maintenance, just like in __flush_dcache_page. The code for that isn't shared because we need the page address in __update_cache so sharing became messy. Given that the entirity is an extra 5 lines, just duplicate it. Signed-off-by: Paul Burton <paul.burton@imgtec.com> Cc: Lars Persson <lars.persson@axis.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Jerome Marchand <jmarchan@redhat.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Cc: stable <stable@vger.kernel.org> # v4.1+ Patchwork: https://patchwork.linux-mips.org/patch/12721/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2016-05-13MIPS: Flush highmem pages in __flush_dcache_pagePaul Burton1-3/+9
When flush_dcache_page is called on an executable page, that page is about to be provided to userland & we can presume that the icache contains no valid entries for its address range. However if the icache does not fill from the dcache then we cannot presume that the pages content has been written back as far as the memories that the dcache will fill from (ie. L2 or further out). This was being done for lowmem pages, but not for highmem which can lead to icache corruption. Fix this by mapping highmem pages & flushing their content from the dcache in __flush_dcache_page before providing the page to userland, just as is done for lowmem pages. Signed-off-by: Paul Burton <paul.burton@imgtec.com> Cc: Lars Persson <lars.persson@axis.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/12720/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2016-05-13MIPS: Add M6250 cases to CPU switch statementsPaul Burton1-0/+1
Add casses supporting the M6250 CPU to various switch statements in the core MIPS kernel code that define behaviour dependent upon the CPU. Signed-off-by: Paul Burton <paul.burton@imgtec.com> Cc: Joshua Kinard <kumba@gentoo.org> Cc: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Maciej W. Rozycki <macro@codesourcery.com> Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/12374/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2016-05-13MIPS: Add P6600 cases to CPU switch statementsPaul Burton2-0/+2
Add cases supporting the P6600 CPU to various switch statements in core MIPS kernel code that define behaviour dependent upon the CPU. Signed-off-by: Paul Burton <paul.burton@imgtec.com> Cc: Maciej W. Rozycki <macro@imgtec.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Joshua Kinard <kumba@gentoo.org> Cc: Andrzej Hajda <a.hajda@samsung.com> Cc: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: James Hogan <james.hogan@imgtec.com> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Petri Gynther <pgynther@google.com> Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/12343/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>