From cc92c28b2db5b406657ecc05235d4ca4e222ae34 Mon Sep 17 00:00:00 2001 From: Nicolas Pitre Date: Mon, 14 Jun 2010 21:16:19 -0400 Subject: [ARM] add address randomization to mmap() Signed-off-by: Nicolas Pitre --- arch/arm/mm/mmap.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'arch/arm/mm') diff --git a/arch/arm/mm/mmap.c b/arch/arm/mm/mmap.c index f5abc51c5a07..4f5b39687df5 100644 --- a/arch/arm/mm/mmap.c +++ b/arch/arm/mm/mmap.c @@ -7,6 +7,7 @@ #include #include #include +#include #include #include @@ -80,6 +81,9 @@ arch_get_unmapped_area(struct file *filp, unsigned long addr, start_addr = addr = TASK_UNMAPPED_BASE; mm->cached_hole_size = 0; } + /* 8 bits of randomness in 20 address space bits */ + if (current->flags & PF_RANDOMIZE) + addr += (get_random_int() % (1 << 8)) << PAGE_SHIFT; full_search: if (do_align) -- cgit v1.2.3 From 3260e5293727f16ffdce9a6a6203fd9a6b149e58 Mon Sep 17 00:00:00 2001 From: Michael Bohan Date: Mon, 14 Jun 2010 13:06:56 -0700 Subject: arm: mm: Don't free prohibited memmap entries The VM subsystem assumes that there are valid memmap entries to the bank end aligned to MAX_ORDER_NR_PAGES. It will try and read these page structs, and so we cannot free any memmap entries that it may inspect. Signed-off-by: Michael Bohan Signed-off-by: Daniel Walker --- arch/arm/mm/init.c | 19 +++++++++---------- 1 file changed, 9 insertions(+), 10 deletions(-) (limited to 'arch/arm/mm') diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c index f6a999465323..e18c7cedb482 100644 --- a/arch/arm/mm/init.c +++ b/arch/arm/mm/init.c @@ -495,28 +495,27 @@ static void __init free_unused_memmap_node(int node, struct meminfo *mi) unsigned int i; /* - * [FIXME] This relies on each bank being in address order. This - * may not be the case, especially if the user has provided the - * information on the command line. + * This relies on each bank being in address order. + * The banks are sorted previously in bootmem_init(). */ for_each_nodebank(i, mi, node) { struct membank *bank = &mi->bank[i]; bank_start = bank_pfn_start(bank); - if (bank_start < prev_bank_end) { - printk(KERN_ERR "MEM: unordered memory banks. " - "Not freeing memmap.\n"); - break; - } /* * If we had a previous bank, and there is a space * between the current bank and the previous, free it. */ - if (prev_bank_end && prev_bank_end != bank_start) + if (prev_bank_end && prev_bank_end < bank_start) free_memmap(node, prev_bank_end, bank_start); - prev_bank_end = bank_pfn_end(bank); + /* + * Align up here since the VM subsystem insists that the + * memmap entries are valid from the bank end aligned to + * MAX_ORDER_NR_PAGES. + */ + prev_bank_end = ALIGN(bank_pfn_end(bank), MAX_ORDER_NR_PAGES); } } -- cgit v1.2.3