diff options
| author | Christophe Leroy <christophe.leroy@c-s.fr> | 2017-08-02 15:51:05 +0200 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2017-08-15 22:55:57 +1000 |
| commit | 95902e6c8864d39b09134dcaa3c99d8161d1deea (patch) | |
| tree | cb41417a8e6436b46a3b504fe73641b4234d5262 /arch | |
| parent | 3184cc4b6f6a1dc0c1745aafe2b14b1206ef3187 (diff) | |
powerpc/mm: Implement STRICT_KERNEL_RWX on PPC32
This patch implements STRICT_KERNEL_RWX on PPC32.
As for CONFIG_DEBUG_PAGEALLOC, it deactivates BAT and LTLB mappings
in order to allow page protection setup at the level of each page.
As BAT/LTLB mappings are deactivated, there might be a performance
impact.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/powerpc/Kconfig | 2 | ||||
| -rw-r--r-- | arch/powerpc/kernel/vmlinux.lds.S | 2 | ||||
| -rw-r--r-- | arch/powerpc/mm/init_32.c | 6 | ||||
| -rw-r--r-- | arch/powerpc/mm/pgtable_32.c | 24 |
4 files changed, 32 insertions, 2 deletions
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index a2b669729440..bf6abab46dcc 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -176,7 +176,7 @@ config PPC select HAVE_ARCH_MMAP_RND_COMPAT_BITS if COMPAT select HAVE_ARCH_SECCOMP_FILTER select HAVE_ARCH_TRACEHOOK - select ARCH_HAS_STRICT_KERNEL_RWX if (PPC_BOOK3S_64 && !RELOCATABLE && !HIBERNATION) + select ARCH_HAS_STRICT_KERNEL_RWX if ((PPC_BOOK3S_64 || PPC32) && !RELOCATABLE && !HIBERNATION) select ARCH_OPTIONAL_KERNEL_RWX if ARCH_HAS_STRICT_KERNEL_RWX select HAVE_CBPF_JIT if !PPC64 select HAVE_CONTEXT_TRACKING if PPC64 diff --git a/arch/powerpc/kernel/vmlinux.lds.S b/arch/powerpc/kernel/vmlinux.lds.S index b1a250560198..882628fa6987 100644 --- a/arch/powerpc/kernel/vmlinux.lds.S +++ b/arch/powerpc/kernel/vmlinux.lds.S @@ -8,7 +8,7 @@ #include <asm/cache.h> #include <asm/thread_info.h> -#ifdef CONFIG_STRICT_KERNEL_RWX +#if defined(CONFIG_STRICT_KERNEL_RWX) && !defined(CONFIG_PPC32) #define STRICT_ALIGN_SIZE (1 << 24) #else #define STRICT_ALIGN_SIZE PAGE_SIZE diff --git a/arch/powerpc/mm/init_32.c b/arch/powerpc/mm/init_32.c index 8a7c38b8d335..7d5fee1bb116 100644 --- a/arch/powerpc/mm/init_32.c +++ b/arch/powerpc/mm/init_32.c @@ -113,6 +113,12 @@ void __init MMU_setup(void) __map_without_bats = 1; __map_without_ltlbs = 1; } +#ifdef CONFIG_STRICT_KERNEL_RWX + if (rodata_enabled) { + __map_without_bats = 1; + __map_without_ltlbs = 1; + } +#endif } /* diff --git a/arch/powerpc/mm/pgtable_32.c b/arch/powerpc/mm/pgtable_32.c index 85e8f0e0efe6..4a3dd9fc6989 100644 --- a/arch/powerpc/mm/pgtable_32.c +++ b/arch/powerpc/mm/pgtable_32.c @@ -34,6 +34,7 @@ #include <asm/fixmap.h> #include <asm/io.h> #include <asm/setup.h> +#include <asm/sections.h> #include "mmu_decl.h" @@ -375,6 +376,29 @@ void mark_initmem_nx(void) change_page_attr(page, numpages, PAGE_KERNEL); } +#ifdef CONFIG_STRICT_KERNEL_RWX +void mark_rodata_ro(void) +{ + struct page *page; + unsigned long numpages; + + page = virt_to_page(_stext); + numpages = PFN_UP((unsigned long)_etext) - + PFN_DOWN((unsigned long)_stext); + + change_page_attr(page, numpages, PAGE_KERNEL_ROX); + /* + * mark .rodata as read only. Use __init_begin rather than __end_rodata + * to cover NOTES and EXCEPTION_TABLE. + */ + page = virt_to_page(__start_rodata); + numpages = PFN_UP((unsigned long)__init_begin) - + PFN_DOWN((unsigned long)__start_rodata); + + change_page_attr(page, numpages, PAGE_KERNEL_RO); +} +#endif + #ifdef CONFIG_DEBUG_PAGEALLOC void __kernel_map_pages(struct page *page, int numpages, int enable) { |