From fa7f9189e017213bad63b93a76de5c715cd62a96 Mon Sep 17 00:00:00 2001 From: Michael Ellerman Date: Fri, 14 Jul 2017 16:51:22 +1000 Subject: [PATCH] powerpc/mm/hash: Refactor hash__mark_rodata_ro() Move the core logic into a helper, so we can use it for changing other permissions. We also change the logic to align start down, and end up. This means calling the function with a range will expand that range to be at least 1 mmu_linear_psize page in size. We need that so we can use it on __init_begin ... __init_end which is not a full page in size. This should always work for _stext/__init_begin, because we align __init_begin to _stext + 16M in the linker script. Signed-off-by: Michael Ellerman Reviewed-by: Balbir Singh Signed-off-by: Michael Ellerman --- arch/powerpc/mm/pgtable-hash64.c | 32 +++++++++++++++++++------------- 1 file changed, 19 insertions(+), 13 deletions(-) diff --git a/arch/powerpc/mm/pgtable-hash64.c b/arch/powerpc/mm/pgtable-hash64.c index 188b410..73019c5 100644 --- a/arch/powerpc/mm/pgtable-hash64.c +++ b/arch/powerpc/mm/pgtable-hash64.c @@ -425,33 +425,39 @@ int hash__has_transparent_hugepage(void) #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ #ifdef CONFIG_STRICT_KERNEL_RWX -void hash__mark_rodata_ro(void) +static bool hash__change_memory_range(unsigned long start, unsigned long end, + unsigned long newpp) { - unsigned long start = (unsigned long)_stext; - unsigned long end = (unsigned long)__init_begin; unsigned long idx; unsigned int step, shift; - unsigned long newpp = PP_RXXX; shift = mmu_psize_defs[mmu_linear_psize].shift; step = 1 << shift; - start = ((start + step - 1) >> shift) << shift; - end = (end >> shift) << shift; + start = ALIGN_DOWN(start, step); + end = ALIGN(end, step); // aligns up - pr_devel("marking ro start %lx, end %lx, step %x\n", - start, end, step); + if (start >= end) + return false; - if (start == end) { - pr_warn("could not set rodata ro, relocate the start" - " of the kernel to a 0x%x boundary\n", step); - return; - } + pr_debug("Changing page protection on range 0x%lx-0x%lx, to 0x%lx, step 0x%x\n", + start, end, newpp, step); for (idx = start; idx < end; idx += step) /* Not sure if we can do much with the return value */ mmu_hash_ops.hpte_updateboltedpp(newpp, idx, mmu_linear_psize, mmu_kernel_ssize); + return true; +} + +void hash__mark_rodata_ro(void) +{ + unsigned long start, end; + + start = (unsigned long)_stext; + end = (unsigned long)__init_begin; + + WARN_ON(!hash__change_memory_range(start, end, PP_RXXX)); } #endif -- 2.7.4