From dd65a941f6ba473a5cb9d013d57fa43b48450a04 Mon Sep 17 00:00:00 2001 From: Marek Szyprowski Date: Tue, 12 Jun 2018 13:08:40 +0200 Subject: arm64: dma-mapping: clear buffers allocated with FORCE_CONTIGUOUS flag dma_alloc_*() buffers might be exposed to userspace via mmap() call, so they should be cleared on allocation. In case of IOMMU-based dma-mapping implementation such buffer clearing was missing in the code path for DMA_ATTR_FORCE_CONTIGUOUS flag handling, because dma_alloc_from_contiguous() doesn't honor __GFP_ZERO flag. This patch fixes this issue. For more information on clearing buffers allocated by dma_alloc_* functions, see commit 6829e274a623 ("arm64: dma-mapping: always clear allocated buffers"). Fixes: 44176bb38fa4 ("arm64: Add support for DMA_ATTR_FORCE_CONTIGUOUS to IOMMU") Signed-off-by: Marek Szyprowski Signed-off-by: Catalin Marinas --- arch/arm64/mm/dma-mapping.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c index 49e217ac7e1e..61e93f0b5482 100644 --- a/arch/arm64/mm/dma-mapping.c +++ b/arch/arm64/mm/dma-mapping.c @@ -583,13 +583,14 @@ static void *__iommu_alloc_attrs(struct device *dev, size_t size, size >> PAGE_SHIFT); return NULL; } - if (!coherent) - __dma_flush_area(page_to_virt(page), iosize); - addr = dma_common_contiguous_remap(page, size, VM_USERMAP, prot, __builtin_return_address(0)); - if (!addr) { + if (addr) { + memset(addr, 0, size); + if (!coherent) + __dma_flush_area(page_to_virt(page), iosize); + } else { iommu_dma_unmap_page(dev, *handle, iosize, 0, attrs); dma_release_from_contiguous(dev, page, size >> PAGE_SHIFT); -- cgit v1.2.3-70-g09d2 From b154886f7892499d0d3054026e19dfb9a731df61 Mon Sep 17 00:00:00 2001 From: Zhizhou Zhang Date: Tue, 12 Jun 2018 17:07:37 +0800 Subject: arm64: make secondary_start_kernel() notrace We can't call function trace hook before setup percpu offset. When entering secondary_start_kernel(), percpu offset has not been initialized. So this lead hotplug malfunction. Here is the flow to reproduce this bug: echo 0 > /sys/devices/system/cpu/cpu1/online echo function > /sys/kernel/debug/tracing/current_tracer echo 1 > /sys/kernel/debug/tracing/tracing_on echo 1 > /sys/devices/system/cpu/cpu1/online Acked-by: Mark Rutland Tested-by: Suzuki K Poulose Signed-off-by: Zhizhou Zhang Signed-off-by: Catalin Marinas --- arch/arm64/kernel/smp.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c index f3e2e3aec0b0..2faa9863d2e5 100644 --- a/arch/arm64/kernel/smp.c +++ b/arch/arm64/kernel/smp.c @@ -179,7 +179,7 @@ int __cpu_up(unsigned int cpu, struct task_struct *idle) * This is the secondary CPU boot entry. We're using this CPUs * idle thread stack, but a set of temporary page tables. */ -asmlinkage void secondary_start_kernel(void) +asmlinkage notrace void secondary_start_kernel(void) { u64 mpidr = read_cpuid_mpidr() & MPIDR_HWID_BITMASK; struct mm_struct *mm = &init_mm; -- cgit v1.2.3-70-g09d2 From b5b7dd647f2d21b93f734ce890671cd908e69b0a Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Fri, 22 Jun 2018 10:25:25 +0100 Subject: arm64: kpti: Use early_param for kpti= command-line option We inspect __kpti_forced early on as part of the cpufeature enable callback which remaps the swapper page table using non-global entries. Ensure that __kpti_forced has been updated to reflect the kpti= command-line option before we start using it. Fixes: ea1e3de85e94 ("arm64: entry: Add fake CPU feature for unmapping the kernel at EL0") Cc: # 4.16.x- Reported-by: Wei Xu Tested-by: Sudeep Holla Tested-by: Wei Xu Signed-off-by: Will Deacon Signed-off-by: Catalin Marinas --- arch/arm64/kernel/cpufeature.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index d2856b129097..f24892a40d2c 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -937,7 +937,7 @@ static int __init parse_kpti(char *str) __kpti_forced = enabled ? 1 : -1; return 0; } -__setup("kpti=", parse_kpti); +early_param("kpti", parse_kpti); #endif /* CONFIG_UNMAP_KERNEL_AT_EL0 */ #ifdef CONFIG_ARM64_HW_AFDBM -- cgit v1.2.3-70-g09d2 From 71c8fc0c96abf8e53e74ed4d891d671e585f9076 Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Fri, 22 Jun 2018 16:23:45 +0100 Subject: arm64: mm: Ensure writes to swapper are ordered wrt subsequent cache maintenance When rewriting swapper using nG mappings, we must performance cache maintenance around each page table access in order to avoid coherency problems with the host's cacheable alias under KVM. To ensure correct ordering of the maintenance with respect to Device memory accesses made with the Stage-1 MMU disabled, DMBs need to be added between the maintenance and the corresponding memory access. This patch adds a missing DMB between writing a new page table entry and performing a clean+invalidate on the same line. Fixes: f992b4dfd58b ("arm64: kpti: Add ->enable callback to remap swapper using nG mappings") Cc: # 4.16.x- Acked-by: Mark Rutland Signed-off-by: Will Deacon Signed-off-by: Catalin Marinas --- arch/arm64/mm/proc.S | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S index 5f9a73a4452c..03646e6a2ef4 100644 --- a/arch/arm64/mm/proc.S +++ b/arch/arm64/mm/proc.S @@ -217,8 +217,9 @@ ENDPROC(idmap_cpu_replace_ttbr1) .macro __idmap_kpti_put_pgtable_ent_ng, type orr \type, \type, #PTE_NG // Same bit for blocks and pages - str \type, [cur_\()\type\()p] // Update the entry and ensure it - dc civac, cur_\()\type\()p // is visible to all CPUs. + str \type, [cur_\()\type\()p] // Update the entry and ensure + dmb sy // that it is visible to all + dc civac, cur_\()\type\()p // CPUs. .endm /* -- cgit v1.2.3-70-g09d2