diff options
Diffstat (limited to 'arch/x86/mm/init_32.c')
| -rw-r--r-- | arch/x86/mm/init_32.c | 41 |
1 files changed, 7 insertions, 34 deletions
diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c index 7116a727fd5a..097089a5e4d5 100644 --- a/arch/x86/mm/init_32.c +++ b/arch/x86/mm/init_32.c @@ -56,8 +56,6 @@ unsigned long highstart_pfn, highend_pfn; -static noinline int do_test_wp_bit(void); - bool __read_mostly __vmalloc_start_set = false; /* @@ -726,22 +724,21 @@ void __init paging_init(void) */ static void __init test_wp_bit(void) { - int wp_works_ok; + char z = 0; printk(KERN_INFO "Checking if this processor honours the WP bit even in supervisor mode..."); - /* Any page-aligned address will do, the test is non-destructive */ - __set_fixmap(FIX_WP_TEST, __pa(&swapper_pg_dir), PAGE_KERNEL_RO); - wp_works_ok = do_test_wp_bit(); - clear_fixmap(FIX_WP_TEST); + __set_fixmap(FIX_WP_TEST, __pa_symbol(empty_zero_page), PAGE_KERNEL_RO); - if (!wp_works_ok) { + if (probe_kernel_write((char *)fix_to_virt(FIX_WP_TEST), &z, 1) == 0) { printk(KERN_CONT "No.\n"); panic("Linux doesn't support CPUs with broken WP."); - } else { - printk(KERN_CONT "Ok.\n"); } + + clear_fixmap(FIX_WP_TEST); + + printk(KERN_CONT "Ok.\n"); } void __init mem_init(void) @@ -851,30 +848,6 @@ int arch_remove_memory(u64 start, u64 size) #endif #endif -/* - * This function cannot be __init, since exceptions don't work in that - * section. Put this after the callers, so that it cannot be inlined. - */ -static noinline int do_test_wp_bit(void) -{ - char tmp_reg; - int flag; - - __asm__ __volatile__( - " movb %0, %1 \n" - "1: movb %1, %0 \n" - " xorl %2, %2 \n" - "2: \n" - _ASM_EXTABLE(1b,2b) - :"=m" (*(char *)fix_to_virt(FIX_WP_TEST)), - "=q" (tmp_reg), - "=r" (flag) - :"2" (1) - :"memory"); - - return flag; -} - int kernel_set_to_readonly __read_mostly; void set_kernel_text_rw(void) |