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authorMichael Ellerman <mpe@ellerman.id.au>2017-07-14 08:51:22 +0200
committerMichael Ellerman <mpe@ellerman.id.au>2017-07-18 10:51:35 +0200
commitfa7f9189e017213bad63b93a76de5c715cd62a96 (patch)
tree9e9fb6eda98403580b55963540c6546d1dab4c69
parentpowerpc/mm/radix: Refactor radix__mark_rodata_ro() (diff)
downloadlinux-fa7f9189e017213bad63b93a76de5c715cd62a96.tar.xz
linux-fa7f9189e017213bad63b93a76de5c715cd62a96.zip
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 <mpe@ellerman.id.au> Reviewed-by: Balbir Singh <bsingharora@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
-rw-r--r--arch/powerpc/mm/pgtable-hash64.c32
1 files changed, 19 insertions, 13 deletions
diff --git a/arch/powerpc/mm/pgtable-hash64.c b/arch/powerpc/mm/pgtable-hash64.c
index 188b4107584d..73019c52141f 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