From 2efef8aa0f8f7f6277ffebe4ea6744fc93d54644 Mon Sep 17 00:00:00 2001
From: David Brown <david.brown@xxxxxxxxxx> Date: Wed, 27 Jan 2016 13:58:44 -0800 This removes the CONFIG_DEBUG_RODATA option and makes it always enabled. Signed-off-by: David Brown <david.brown@xxxxxxxxxx> --- v1: This is in the same spirit as the x86 patch, removing allowing this option to be config selected. The associated patch series adds a runtime option for the same thing. However, it does affect the way some things are mapped, and could possibly result in either increased memory usage, or a performance hit (due to TLB misses from 4K pages). I've tested this on a Hikey 96board (hi6220-hikey.dtb), both with and without 'rodata=off' on the command line. arch/arm64/Kconfig | 3 +++ arch/arm64/Kconfig.debug | 10 ---------- arch/arm64/kernel/insn.c | 2 +- arch/arm64/kernel/vmlinux.lds.S | 5 +---- arch/arm64/mm/mmu.c | 12 ------------ 5 files changed, 5 insertions(+), 27 deletions(-) diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 8cc6228..ffa617a 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -201,6 +201,9 @@ config KERNEL_MODE_NEON config FIX_EARLYCON_MEM def_bool y +config DEBUG_RODATA + def_bool y + config PGTABLE_LEVELS int default 2 if ARM64_16K_PAGES && ARM64_VA_BITS_36 diff --git a/arch/arm64/Kconfig.debug b/arch/arm64/Kconfig.debug index e13c4bf..db994ec 100644 --- a/arch/arm64/Kconfig.debug +++ b/arch/arm64/Kconfig.debug @@ -48,16 +48,6 @@ config DEBUG_SET_MODULE_RONX against certain classes of kernel exploits. If in doubt, say "N". -config DEBUG_RODATA - bool "Make kernel text and rodata read-only" - help - If this is set, kernel text and rodata will be made read-only. This - is to help catch accidental or malicious attempts to change the - kernel's executable code. Additionally splits rodata from kernel - text so it can be made explicitly non-executable. - - If in doubt, say Y - config DEBUG_ALIGN_RODATA depends on DEBUG_RODATA && ARM64_4K_PAGES bool "Align linker sections up to SECTION_SIZE" diff --git a/arch/arm64/kernel/insn.c b/arch/arm64/kernel/insn.c index 7371455..a04bdef 100644 --- a/arch/arm64/kernel/insn.c +++ b/arch/arm64/kernel/insn.c @@ -95,7 +95,7 @@ static void __kprobes *patch_map(void *addr, int fixmap) if (module && IS_ENABLED(CONFIG_DEBUG_SET_MODULE_RONX)) page = vmalloc_to_page(addr); - else if (!module && IS_ENABLED(CONFIG_DEBUG_RODATA)) + else if (!module) page = virt_to_page(addr); else return addr; diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S index e3928f5..f80903c 100644 --- a/arch/arm64/kernel/vmlinux.lds.S +++ b/arch/arm64/kernel/vmlinux.lds.S @@ -65,12 +65,9 @@ PECOFF_FILE_ALIGNMENT = 0x200; #if defined(CONFIG_DEBUG_ALIGN_RODATA) #define ALIGN_DEBUG_RO . = ALIGN(1<<SECTION_SHIFT); #define ALIGN_DEBUG_RO_MIN(min) ALIGN_DEBUG_RO -#elif defined(CONFIG_DEBUG_RODATA) +#else #define ALIGN_DEBUG_RO . = ALIGN(1<<PAGE_SHIFT); #define ALIGN_DEBUG_RO_MIN(min) ALIGN_DEBUG_RO -#else -#define ALIGN_DEBUG_RO -#define ALIGN_DEBUG_RO_MIN(min) . = ALIGN(min); #endif SECTIONS diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index 58faeaa..3b411b7 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -313,7 +313,6 @@ static void create_mapping_late(phys_addr_t phys, unsigned long virt, phys, virt, size, prot, late_alloc); } -#ifdef CONFIG_DEBUG_RODATA static void __init __map_memblock(phys_addr_t start, phys_addr_t end) { /* @@ -347,13 +346,6 @@ static void __init __map_memblock(phys_addr_t start, phys_addr_t end) } } -#else -static void __init __map_memblock(phys_addr_t start, phys_addr_t end) -{ - create_mapping(start, __phys_to_virt(start), end - start, - PAGE_KERNEL_EXEC); -} -#endif static void __init map_mem(void) { @@ -410,7 +402,6 @@ static void __init map_mem(void) static void __init fixup_executable(void) { -#ifdef CONFIG_DEBUG_RODATA /* now that we are actually fully mapped, make the start/end more fine grained */ if (!IS_ALIGNED((unsigned long)_stext, SWAPPER_BLOCK_SIZE)) { unsigned long aligned_start = round_down(__pa(_stext), @@ -428,10 +419,8 @@ static void __init fixup_executable(void) aligned_end - __pa(__init_end), PAGE_KERNEL); } -#endif } -#ifdef CONFIG_DEBUG_RODATA void mark_rodata_ro(void) { create_mapping_late(__pa(_stext), (unsigned long)_stext, @@ -439,7 +428,6 @@ void mark_rodata_ro(void) PAGE_KERNEL_ROX); } -#endif void fixup_init(void) { -- 2.7.0 -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html