diff options
Diffstat (limited to 'arch/x86_64')
| -rw-r--r-- | arch/x86_64/Kconfig.debug | 10 | ||||
| -rw-r--r-- | arch/x86_64/ia32/ia32entry.S | 2 | ||||
| -rw-r--r-- | arch/x86_64/kernel/process.c | 5 | ||||
| -rw-r--r-- | arch/x86_64/kernel/syscall.c | 2 | ||||
| -rw-r--r-- | arch/x86_64/mm/init.c | 23 | ||||
| -rw-r--r-- | arch/x86_64/mm/pageattr.c | 9 |
6 files changed, 45 insertions, 6 deletions
diff --git a/arch/x86_64/Kconfig.debug b/arch/x86_64/Kconfig.debug index e2c6e64a85ec..fcb06a50fdd2 100644 --- a/arch/x86_64/Kconfig.debug +++ b/arch/x86_64/Kconfig.debug @@ -9,6 +9,16 @@ config INIT_DEBUG Fill __init and __initdata at the end of boot. This helps debugging illegal uses of __init and __initdata after initialization. +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 2MB TLB anymore. + If in doubt, say "N". + config IOMMU_DEBUG depends on GART_IOMMU && DEBUG_KERNEL bool "Enable IOMMU debugging" diff --git a/arch/x86_64/ia32/ia32entry.S b/arch/x86_64/ia32/ia32entry.S index e0eb0c712fe9..df0773c9bdbe 100644 --- a/arch/x86_64/ia32/ia32entry.S +++ b/arch/x86_64/ia32/ia32entry.S @@ -341,7 +341,7 @@ ENTRY(ia32_ptregs_common) jmp ia32_sysret /* misbalances the return cache */ CFI_ENDPROC - .data + .section .rodata,"a" .align 8 .globl ia32_sys_call_table ia32_sys_call_table: diff --git a/arch/x86_64/kernel/process.c b/arch/x86_64/kernel/process.c index 7519fc520eb3..3060ed97b755 100644 --- a/arch/x86_64/kernel/process.c +++ b/arch/x86_64/kernel/process.c @@ -157,7 +157,7 @@ EXPORT_SYMBOL_GPL(cpu_idle_wait); DECLARE_PER_CPU(int, cpu_state); #include <asm/nmi.h> -/* We don't actually take CPU down, just spin without interrupts. */ +/* We halt the CPU with physical CPU hotplug */ static inline void play_dead(void) { idle_task_exit(); @@ -166,8 +166,9 @@ static inline void play_dead(void) /* Ack it */ __get_cpu_var(cpu_state) = CPU_DEAD; + local_irq_disable(); while (1) - safe_halt(); + halt(); } #else static inline void play_dead(void) diff --git a/arch/x86_64/kernel/syscall.c b/arch/x86_64/kernel/syscall.c index e263685f864c..7c176b3edde0 100644 --- a/arch/x86_64/kernel/syscall.c +++ b/arch/x86_64/kernel/syscall.c @@ -19,7 +19,7 @@ typedef void (*sys_call_ptr_t)(void); extern void sys_ni_syscall(void); -sys_call_ptr_t sys_call_table[__NR_syscall_max+1] __cacheline_aligned = { +const sys_call_ptr_t sys_call_table[__NR_syscall_max+1] = { /* Smells like a like a compiler bug -- it doesn't work when the & below is removed. */ [0 ... __NR_syscall_max] = &sys_ni_syscall, #include <asm-x86_64/unistd.h> diff --git a/arch/x86_64/mm/init.c b/arch/x86_64/mm/init.c index c016dfe84784..1faae5fc1c01 100644 --- a/arch/x86_64/mm/init.c +++ b/arch/x86_64/mm/init.c @@ -498,6 +498,29 @@ void free_initmem(void) printk ("Freeing unused kernel memory: %luk freed\n", (__init_end - __init_begin) >> 10); } +#ifdef CONFIG_DEBUG_RODATA + +extern char __start_rodata, __end_rodata; +void mark_rodata_ro(void) +{ + unsigned long addr = (unsigned long)&__start_rodata; + + for (; addr < (unsigned long)&__end_rodata; addr += PAGE_SIZE) + change_page_attr_addr(addr, 1, PAGE_KERNEL_RO); + + printk ("Write protecting the kernel read-only data: %luk\n", + (&__end_rodata - &__start_rodata) >> 10); + + /* + * change_page_attr_addr() requires a global_flush_tlb() call after it. + * We do this after the printk so that if something went wrong in the + * change, the printk gets out at least to give a better debug hint + * of who is the culprit. + */ + global_flush_tlb(); +} +#endif + #ifdef CONFIG_BLK_DEV_INITRD void free_initrd_mem(unsigned long start, unsigned long end) { diff --git a/arch/x86_64/mm/pageattr.c b/arch/x86_64/mm/pageattr.c index b90e8fe9eeb0..35f1f1aab063 100644 --- a/arch/x86_64/mm/pageattr.c +++ b/arch/x86_64/mm/pageattr.c @@ -128,6 +128,7 @@ __change_page_attr(unsigned long address, unsigned long pfn, pgprot_t prot, pte_t *kpte; struct page *kpte_page; unsigned kpte_flags; + pgprot_t ref_prot2; kpte = lookup_address(address); if (!kpte) return 0; kpte_page = virt_to_page(((unsigned long)kpte) & PAGE_MASK); @@ -140,10 +141,14 @@ __change_page_attr(unsigned long address, unsigned long pfn, pgprot_t prot, * split_large_page will take the reference for this change_page_attr * on the split page. */ - struct page *split = split_large_page(address, prot, ref_prot); + + struct page *split; + ref_prot2 = __pgprot(pgprot_val(pte_pgprot(*lookup_address(address))) & ~(1<<_PAGE_BIT_PSE)); + + split = split_large_page(address, prot, ref_prot2); if (!split) return -ENOMEM; - set_pte(kpte,mk_pte(split, ref_prot)); + set_pte(kpte,mk_pte(split, ref_prot2)); kpte_page = split; } get_page(kpte_page); |