From 1dace6c665ec59bdc4eeafa4db7228c1a673e2e2 Mon Sep 17 00:00:00 2001 From: David Gibson Date: Tue, 9 Feb 2016 13:32:42 +1000 Subject: [PATCH] powerpc/mm: Clean up memory hotplug failure paths This makes a number of cleanups to handling of mapping failures during memory hotplug on Power: For errors creating the linear mapping for the hot-added region: * This is now reported with EFAULT which is more appropriate than the previous EINVAL (the failure is unlikely to be related to the function's parameters) * An error in this path now prints a warning message, rather than just silently failing to add the extra memory. * Previously a failure here could result in the region being partially mapped. We now clean up any partial mapping before failing. For errors creating the vmemmap for the hot-added region: * This is now reported with EFAULT instead of causing a BUG() - this could happen for external reason (e.g. full hash table) so it's better to handle this non-fatally * An error message is also printed, so the failure won't be silent * As above a failure could cause a partially mapped region, we now clean this up. [mpe: move htab_remove_mapping() out of #ifdef CONFIG_MEMORY_HOTPLUG to enable this] Signed-off-by: David Gibson Reviewed-by: Paul Mackerras Reviewed-by: Aneesh Kumar K.V Signed-off-by: Michael Ellerman --- arch/powerpc/mm/hash_utils_64.c | 15 ++++++++++----- arch/powerpc/mm/init_64.c | 38 ++++++++++++++++++++++++++------------ arch/powerpc/mm/mem.c | 10 ++++++++-- 3 files changed, 44 insertions(+), 19 deletions(-) diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c index 44f145a..335cd41 100644 --- a/arch/powerpc/mm/hash_utils_64.c +++ b/arch/powerpc/mm/hash_utils_64.c @@ -263,7 +263,6 @@ int htab_bolt_mapping(unsigned long vstart, unsigned long vend, return ret < 0 ? ret : 0; } -#ifdef CONFIG_MEMORY_HOTPLUG int htab_remove_mapping(unsigned long vstart, unsigned long vend, int psize, int ssize) { @@ -290,7 +289,6 @@ int htab_remove_mapping(unsigned long vstart, unsigned long vend, return ret; } -#endif /* CONFIG_MEMORY_HOTPLUG */ static int __init htab_dt_scan_seg_sizes(unsigned long node, const char *uname, int depth, @@ -640,9 +638,16 @@ static unsigned long __init htab_get_table_size(void) #ifdef CONFIG_MEMORY_HOTPLUG int create_section_mapping(unsigned long start, unsigned long end) { - return htab_bolt_mapping(start, end, __pa(start), - pgprot_val(PAGE_KERNEL), mmu_linear_psize, - mmu_kernel_ssize); + int rc = htab_bolt_mapping(start, end, __pa(start), + pgprot_val(PAGE_KERNEL), mmu_linear_psize, + mmu_kernel_ssize); + + if (rc < 0) { + int rc2 = htab_remove_mapping(start, end, mmu_linear_psize, + mmu_kernel_ssize); + BUG_ON(rc2 && (rc2 != -ENOENT)); + } + return rc; } int remove_section_mapping(unsigned long start, unsigned long end) diff --git a/arch/powerpc/mm/init_64.c b/arch/powerpc/mm/init_64.c index baa1a23..fbc9448c 100644 --- a/arch/powerpc/mm/init_64.c +++ b/arch/powerpc/mm/init_64.c @@ -188,9 +188,9 @@ static int __meminit vmemmap_populated(unsigned long start, int page_size) */ #ifdef CONFIG_PPC_BOOK3E -static void __meminit vmemmap_create_mapping(unsigned long start, - unsigned long page_size, - unsigned long phys) +static int __meminit vmemmap_create_mapping(unsigned long start, + unsigned long page_size, + unsigned long phys) { /* Create a PTE encoding without page size */ unsigned long i, flags = _PAGE_PRESENT | _PAGE_ACCESSED | @@ -208,6 +208,8 @@ static void __meminit vmemmap_create_mapping(unsigned long start, */ for (i = 0; i < page_size; i += PAGE_SIZE) BUG_ON(map_kernel_page(start + i, phys, flags)); + + return 0; } #ifdef CONFIG_MEMORY_HOTPLUG @@ -217,15 +219,20 @@ static void vmemmap_remove_mapping(unsigned long start, } #endif #else /* CONFIG_PPC_BOOK3E */ -static void __meminit vmemmap_create_mapping(unsigned long start, - unsigned long page_size, - unsigned long phys) +static int __meminit vmemmap_create_mapping(unsigned long start, + unsigned long page_size, + unsigned long phys) { - int mapped = htab_bolt_mapping(start, start + page_size, phys, - pgprot_val(PAGE_KERNEL), - mmu_vmemmap_psize, - mmu_kernel_ssize); - BUG_ON(mapped < 0); + int rc = htab_bolt_mapping(start, start + page_size, phys, + pgprot_val(PAGE_KERNEL), + mmu_vmemmap_psize, mmu_kernel_ssize); + if (rc < 0) { + int rc2 = htab_remove_mapping(start, start + page_size, + mmu_vmemmap_psize, + mmu_kernel_ssize); + BUG_ON(rc2 && (rc2 != -ENOENT)); + } + return rc; } #ifdef CONFIG_MEMORY_HOTPLUG @@ -304,6 +311,7 @@ int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node) for (; start < end; start += page_size) { void *p; + int rc; if (vmemmap_populated(start, page_size)) continue; @@ -317,7 +325,13 @@ int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node) pr_debug(" * %016lx..%016lx allocated at %p\n", start, start + page_size, p); - vmemmap_create_mapping(start, page_size, __pa(p)); + rc = vmemmap_create_mapping(start, page_size, __pa(p)); + if (rc < 0) { + pr_warning( + "vmemmap_populate: Unable to create vmemmap mapping: %d\n", + rc); + return -EFAULT; + } } return 0; diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c index d0f0a51..f980da6 100644 --- a/arch/powerpc/mm/mem.c +++ b/arch/powerpc/mm/mem.c @@ -119,12 +119,18 @@ int arch_add_memory(int nid, u64 start, u64 size, bool for_device) struct zone *zone; unsigned long start_pfn = start >> PAGE_SHIFT; unsigned long nr_pages = size >> PAGE_SHIFT; + int rc; pgdata = NODE_DATA(nid); start = (unsigned long)__va(start); - if (create_section_mapping(start, start + size)) - return -EINVAL; + rc = create_section_mapping(start, start + size); + if (rc) { + pr_warning( + "Unable to create mapping for hot added memory 0x%llx..0x%llx: %d\n", + start, start + size, rc); + return -EFAULT; + } /* this should work for most non-highmem platforms */ zone = pgdata->node_zones + -- 2.7.4