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Date: Sat, 11 Feb 2017 20:23:05 +0000
From: Ard Biesheuvel <ard.biesheuvel@...aro.org>
To: linux-arm-kernel@...ts.infradead.org,
mark.rutland@....com,
catalin.marinas@....com,
will.deacon@....com,
labbott@...oraproject.org
Cc: kvmarm@...ts.cs.columbia.edu,
marc.zyngier@....com,
andre.przywara@....com,
Suzuki.Poulose@....com,
james.morse@....com,
keescook@...omium.org,
kernel-hardening@...ts.openwall.com,
Ard Biesheuvel <ard.biesheuvel@...aro.org>
Subject: [PATCH v2 4/5] 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.
Reviewed-by: Laura Abbott <labbott@...hat.com>
Reviewed-by: Kees Cook <keescook@...omium.org>
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 7ed981c7f4c0..e97f1ce967ec 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.
@@ -484,7 +481,7 @@ 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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