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/powerpc/mm | |
| 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/powerpc/mm')
| -rw-r--r-- | arch/powerpc/mm/init_32.c | 6 | ||||
| -rw-r--r-- | arch/powerpc/mm/pgtable_32.c | 24 |
2 files changed, 30 insertions, 0 deletions
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) { |