From mboxrd@z Thu Jan 1 00:00:00 1970 From: ard.biesheuvel@linaro.org (Ard Biesheuvel) Date: Sat, 11 Feb 2017 20:23:05 +0000 Subject: [PATCH v2 4/5] arm64: mmu: map .text as read-only from the outset In-Reply-To: <1486844586-26135-1-git-send-email-ard.biesheuvel@linaro.org> References: <1486844586-26135-1-git-send-email-ard.biesheuvel@linaro.org> Message-ID: <1486844586-26135-5-git-send-email-ard.biesheuvel@linaro.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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 Reviewed-by: Kees Cook Signed-off-by: Ard Biesheuvel --- 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