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Date: Fri, 10 Feb 2017 17:16:44 +0000
From: Ard Biesheuvel <ard.biesheuvel@...aro.org>
To: linux-arm-kernel@...ts.infradead.org,
mark.rutland@....com,
will.deacon@....com,
catalin.marinas@....com,
keescook@...omium.org,
labbott@...oraproject.org,
james.morse@....com
Cc: kvmarm@...ts.cs.columbia.edu,
marc.zyngier@....com,
christoffer.dall@...aro.org,
kernel-hardening@...ts.openwall.com,
andre.przywara@....com,
Ard Biesheuvel <ard.biesheuvel@...aro.org>
Subject: [PATCH 3/4] arm64: mmu: map .text as read-only from the outset
Now that alternatives patching code no longer relies on the primary
mapping of .text being writable, we can remove the code that removes
the writable permissions post-init time, and map it read-only from
the outset.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@...aro.org>
---
arch/arm64/mm/mmu.c | 5 +----
1 file changed, 1 insertion(+), 4 deletions(-)
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index f4b045d1cc53..5b0dbb9156ce 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -442,9 +442,6 @@ void mark_rodata_ro(void)
{
unsigned long section_size;
- section_size = (unsigned long)_etext - (unsigned long)_text;
- create_mapping_late(__pa_symbol(_text), (unsigned long)_text,
- section_size, PAGE_KERNEL_ROX);
/*
* mark .rodata as read only. Use __init_begin rather than __end_rodata
* to cover NOTES and EXCEPTION_TABLE.
@@ -487,7 +484,7 @@ static void __init map_kernel(pgd_t *pgd)
{
static struct vm_struct vmlinux_text, vmlinux_rodata, vmlinux_init, vmlinux_data;
- map_kernel_segment(pgd, _text, _etext, PAGE_KERNEL_EXEC, &vmlinux_text);
+ map_kernel_segment(pgd, _text, _etext, PAGE_KERNEL_ROX, &vmlinux_text);
map_kernel_segment(pgd, __start_rodata, __init_begin, PAGE_KERNEL, &vmlinux_rodata);
map_kernel_segment(pgd, __init_begin, __init_end, PAGE_KERNEL_EXEC,
&vmlinux_init);
--
2.7.4
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