From 0f02cfbc3d9e413d450d8d0fd660077c23f67eff Mon Sep 17 00:00:00 2001 From: Paul Burton Date: Thu, 30 Aug 2018 11:01:21 -0700 Subject: MIPS: VDSO: Match data page cache colouring when D$ aliases When a system suffers from dcache aliasing a user program may observe stale VDSO data from an aliased cache line. Notably this can break the expectation that clock_gettime(CLOCK_MONOTONIC, ...) is, as its name suggests, monotonic. In order to ensure that users observe updates to the VDSO data page as intended, align the user mappings of the VDSO data page such that their cache colouring matches that of the virtual address range which the kernel will use to update the data page - typically its unmapped address within kseg0. This ensures that we don't introduce aliasing cache lines for the VDSO data page, and therefore that userland will observe updates without requiring cache invalidation. Signed-off-by: Paul Burton Reported-by: Hauke Mehrtens Reported-by: Rene Nielsen Reported-by: Alexandre Belloni Fixes: ebb5e78cc634 ("MIPS: Initial implementation of a VDSO") Patchwork: https://patchwork.linux-mips.org/patch/20344/ Tested-by: Alexandre Belloni Tested-by: Hauke Mehrtens Cc: James Hogan Cc: linux-mips@linux-mips.org Cc: stable@vger.kernel.org # v4.4+ --- arch/mips/kernel/vdso.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) (limited to 'arch/mips') diff --git a/arch/mips/kernel/vdso.c b/arch/mips/kernel/vdso.c index 019035d7225c..8f845f6e5f42 100644 --- a/arch/mips/kernel/vdso.c +++ b/arch/mips/kernel/vdso.c @@ -13,6 +13,7 @@ #include #include #include +#include #include #include #include @@ -20,6 +21,7 @@ #include #include +#include #include /* Kernel-provided data used by the VDSO. */ @@ -128,12 +130,30 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp) vvar_size = gic_size + PAGE_SIZE; size = vvar_size + image->size; + /* + * Find a region that's large enough for us to perform the + * colour-matching alignment below. + */ + if (cpu_has_dc_aliases) + size += shm_align_mask + 1; + base = get_unmapped_area(NULL, 0, size, 0, 0); if (IS_ERR_VALUE(base)) { ret = base; goto out; } + /* + * If we suffer from dcache aliasing, ensure that the VDSO data page + * mapping is coloured the same as the kernel's mapping of that memory. + * This ensures that when the kernel updates the VDSO data userland + * will observe it without requiring cache invalidations. + */ + if (cpu_has_dc_aliases) { + base = __ALIGN_MASK(base, shm_align_mask); + base += ((unsigned long)&vdso_data - gic_size) & shm_align_mask; + } + data_addr = base + gic_size; vdso_addr = data_addr + PAGE_SIZE; -- cgit v1.2.1 From a35381e10dc46dd75e65e4b3832d9a0005d48d44 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Thu, 23 Aug 2018 10:18:14 +0100 Subject: KVM: Remove obsolete kvm_unmap_hva notifier backend kvm_unmap_hva is long gone, and we only have kvm_unmap_hva_range to deal with. Drop the now obsolete code. Fixes: fb1522e099f0 ("KVM: update to new mmu_notifier semantic v2") Cc: James Hogan Reviewed-by: Paolo Bonzini Signed-off-by: Marc Zyngier Signed-off-by: Christoffer Dall --- arch/mips/include/asm/kvm_host.h | 1 - arch/mips/kvm/mmu.c | 10 ---------- 2 files changed, 11 deletions(-) (limited to 'arch/mips') diff --git a/arch/mips/include/asm/kvm_host.h b/arch/mips/include/asm/kvm_host.h index a9af1d2dcd69..2c1c53d12179 100644 --- a/arch/mips/include/asm/kvm_host.h +++ b/arch/mips/include/asm/kvm_host.h @@ -931,7 +931,6 @@ enum kvm_mips_fault_result kvm_trap_emul_gva_fault(struct kvm_vcpu *vcpu, bool write); #define KVM_ARCH_WANT_MMU_NOTIFIER -int kvm_unmap_hva(struct kvm *kvm, unsigned long hva); int kvm_unmap_hva_range(struct kvm *kvm, unsigned long start, unsigned long end); void kvm_set_spte_hva(struct kvm *kvm, unsigned long hva, pte_t pte); diff --git a/arch/mips/kvm/mmu.c b/arch/mips/kvm/mmu.c index ee64db032793..d8dcdb350405 100644 --- a/arch/mips/kvm/mmu.c +++ b/arch/mips/kvm/mmu.c @@ -512,16 +512,6 @@ static int kvm_unmap_hva_handler(struct kvm *kvm, gfn_t gfn, gfn_t gfn_end, return 1; } -int kvm_unmap_hva(struct kvm *kvm, unsigned long hva) -{ - unsigned long end = hva + PAGE_SIZE; - - handle_hva_to_gpa(kvm, hva, end, &kvm_unmap_hva_handler, NULL); - - kvm_mips_callbacks->flush_shadow_all(kvm); - return 0; -} - int kvm_unmap_hva_range(struct kvm *kvm, unsigned long start, unsigned long end) { handle_hva_to_gpa(kvm, start, end, &kvm_unmap_hva_handler, NULL); -- cgit v1.2.1 From 2d946e5bcdabc1deef72d01bc92a2801c71d6d8d Mon Sep 17 00:00:00 2001 From: Hauke Mehrtens Date: Sun, 9 Sep 2018 21:26:23 +0200 Subject: MIPS: lantiq: dma: add dev pointer dma_zalloc_coherent() now crashes if no dev pointer is given. Add a dev pointer to the ltq_dma_channel structure and fill it in the driver using it. This fixes a bug introduced in kernel 4.19. Signed-off-by: Hauke Mehrtens Signed-off-by: David S. Miller --- arch/mips/include/asm/mach-lantiq/xway/xway_dma.h | 1 + arch/mips/lantiq/xway/dma.c | 4 ++-- 2 files changed, 3 insertions(+), 2 deletions(-) (limited to 'arch/mips') diff --git a/arch/mips/include/asm/mach-lantiq/xway/xway_dma.h b/arch/mips/include/asm/mach-lantiq/xway/xway_dma.h index 4901833498f7..8441b2698e64 100644 --- a/arch/mips/include/asm/mach-lantiq/xway/xway_dma.h +++ b/arch/mips/include/asm/mach-lantiq/xway/xway_dma.h @@ -40,6 +40,7 @@ struct ltq_dma_channel { int desc; /* the current descriptor */ struct ltq_dma_desc *desc_base; /* the descriptor base */ int phys; /* physical addr */ + struct device *dev; }; enum { diff --git a/arch/mips/lantiq/xway/dma.c b/arch/mips/lantiq/xway/dma.c index 4b9fbb6744ad..664f2f7f55c1 100644 --- a/arch/mips/lantiq/xway/dma.c +++ b/arch/mips/lantiq/xway/dma.c @@ -130,7 +130,7 @@ ltq_dma_alloc(struct ltq_dma_channel *ch) unsigned long flags; ch->desc = 0; - ch->desc_base = dma_zalloc_coherent(NULL, + ch->desc_base = dma_zalloc_coherent(ch->dev, LTQ_DESC_NUM * LTQ_DESC_SIZE, &ch->phys, GFP_ATOMIC); @@ -182,7 +182,7 @@ ltq_dma_free(struct ltq_dma_channel *ch) if (!ch->desc_base) return; ltq_dma_close(ch); - dma_free_coherent(NULL, LTQ_DESC_NUM * LTQ_DESC_SIZE, + dma_free_coherent(ch->dev, LTQ_DESC_NUM * LTQ_DESC_SIZE, ch->desc_base, ch->phys); } EXPORT_SYMBOL_GPL(ltq_dma_free); -- cgit v1.2.1