diff options
| -rw-r--r-- | arch/parisc/Kconfig.debug | 10 | ||||
| -rw-r--r-- | arch/parisc/hpux/entry_hpux.S | 3 | ||||
| -rw-r--r-- | arch/parisc/kernel/syscall.S | 2 | ||||
| -rw-r--r-- | arch/parisc/mm/init.c | 15 | ||||
| -rw-r--r-- | include/asm-parisc/cacheflush.h | 6 | ||||
| -rw-r--r-- | include/asm-parisc/pgtable.h | 2 |
6 files changed, 34 insertions, 4 deletions
diff --git a/arch/parisc/Kconfig.debug b/arch/parisc/Kconfig.debug index 8caaed187a1..9166bd11726 100644 --- a/arch/parisc/Kconfig.debug +++ b/arch/parisc/Kconfig.debug @@ -11,4 +11,14 @@ config DEBUG_RWLOCK too many attempts. If you suspect a rwlock problem or a kernel hacker asks for this option then say Y. Otherwise say N. +config DEBUG_RODATA + bool "Write protect kernel read-only data structures" + depends on DEBUG_KERNEL + help + Mark the kernel read-only data as write-protected in the pagetables, + in order to catch accidental (and incorrect) writes to such const + data. This option may have a slight performance impact because a + portion of the kernel code won't be covered by a TLB anymore. + If in doubt, say "N". + endmenu diff --git a/arch/parisc/hpux/entry_hpux.S b/arch/parisc/hpux/entry_hpux.S index fa9bf38787e..31c8cccfba3 100644 --- a/arch/parisc/hpux/entry_hpux.S +++ b/arch/parisc/hpux/entry_hpux.S @@ -22,10 +22,9 @@ #include <linux/linkage.h> #include <asm/unistd.h> - .text - #define ENTRY_NAME(_name_) .word _name_ + .section .rodata,"a" .align 4 .export hpux_call_table .import hpux_unimplemented_wrapper diff --git a/arch/parisc/kernel/syscall.S b/arch/parisc/kernel/syscall.S index d6616349289..af88afef41b 100644 --- a/arch/parisc/kernel/syscall.S +++ b/arch/parisc/kernel/syscall.S @@ -650,6 +650,8 @@ end_linux_gateway_page: #define LWS_ENTRY(_name_) .word (lws_##_name_ - linux_gateway_page) #endif + .section .rodata,"a" + .align 4096 /* Light-weight-syscall table */ /* Start of lws table. */ diff --git a/arch/parisc/mm/init.c b/arch/parisc/mm/init.c index 9999eb04523..6f36d0b17d9 100644 --- a/arch/parisc/mm/init.c +++ b/arch/parisc/mm/init.c @@ -417,6 +417,19 @@ void free_initmem(void) #endif } + +#ifdef CONFIG_DEBUG_RODATA +void mark_rodata_ro(void) +{ + extern char __start_rodata, __end_rodata; + /* rodata memory was already mapped with KERNEL_RO access rights by + pagetable_init() and map_pages(). No need to do additional stuff here */ + printk (KERN_INFO "Write protecting the kernel read-only data: %luk\n", + (unsigned long)(&__end_rodata - &__start_rodata) >> 10); +} +#endif + + /* * Just an arbitrary offset to serve as a "hole" between mapping areas * (between top of physical memory and a potential pcxl dma mapping @@ -685,7 +698,7 @@ static void __init pagetable_init(void) #ifdef CONFIG_BLK_DEV_INITRD if (initrd_end && initrd_end > mem_limit) { - printk("initrd: mapping %08lx-%08lx\n", initrd_start, initrd_end); + printk(KERN_INFO "initrd: mapping %08lx-%08lx\n", initrd_start, initrd_end); map_pages(initrd_start, __pa(initrd_start), initrd_end - initrd_start, PAGE_KERNEL); } diff --git a/include/asm-parisc/cacheflush.h b/include/asm-parisc/cacheflush.h index 1bc3c83ee74..c53af9ff41b 100644 --- a/include/asm-parisc/cacheflush.h +++ b/include/asm-parisc/cacheflush.h @@ -183,4 +183,10 @@ flush_cache_page(struct vm_area_struct *vma, unsigned long vmaddr, unsigned long __flush_cache_page(vma, vmaddr); } + +#ifdef CONFIG_DEBUG_RODATA +void mark_rodata_ro(void); #endif + +#endif /* _PARISC_CACHEFLUSH_H */ + diff --git a/include/asm-parisc/pgtable.h b/include/asm-parisc/pgtable.h index b4554711c3e..4e34c6b4405 100644 --- a/include/asm-parisc/pgtable.h +++ b/include/asm-parisc/pgtable.h @@ -213,7 +213,7 @@ extern void *vmalloc_start; #define PAGE_COPY PAGE_EXECREAD #define PAGE_RWX __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_READ | _PAGE_WRITE | _PAGE_EXEC |_PAGE_ACCESSED) #define PAGE_KERNEL __pgprot(_PAGE_KERNEL) -#define PAGE_KERNEL_RO __pgprot(_PAGE_PRESENT | _PAGE_EXEC | _PAGE_READ | _PAGE_DIRTY | _PAGE_ACCESSED) +#define PAGE_KERNEL_RO __pgprot(_PAGE_KERNEL & ~_PAGE_WRITE) #define PAGE_KERNEL_UNC __pgprot(_PAGE_KERNEL | _PAGE_NO_CACHE) #define PAGE_GATEWAY __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_ACCESSED | _PAGE_GATEWAY| _PAGE_READ) #define PAGE_FLUSH __pgprot(_PAGE_FLUSH) |