On 06/03/2015 10:44 AM, Ingo Molnar wrote: > > * Alexander Popov <[email protected]> wrote: > >> #ifdef CONFIG_KASAN >> void __init kasan_map_early_shadow(pgd_t *pgd); >> +void __init kasan_early_init(void); >> void __init kasan_init(void); >> #else >> static inline void kasan_map_early_shadow(pgd_t *pgd) { } >> +static inline void kasan_early_init(void) { } >> static inline void kasan_init(void) { } >> #endif >> >> diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c >> index 2b55ee6..e9a84a1 100644 >> --- a/arch/x86/kernel/head64.c >> +++ b/arch/x86/kernel/head64.c >> @@ -161,11 +161,15 @@ asmlinkage __visible void __init >> x86_64_start_kernel(char * real_mode_data) >> /* Kill off the identity-map trampoline */ >> reset_early_page_tables(); >> >> - kasan_map_early_shadow(early_level4_pgt); >> - >> - /* clear bss before set_intr_gate with early_idt_handler */ >> + /* >> + * Clear bss before kasan_early_init and set_intr_gate >> + * with early_idt_handler >> + */ >> clear_bss(); >> >> + kasan_early_init(); >> + kasan_map_early_shadow(early_level4_pgt); > > So why isn't kasan_map_early_shadow() called in kasan_early_init()? > > High level x86 init code should not be polluted with too many low level > details. >
Agreed. Eventually, with the patch bellow, we could get rid of the second kasan_map_early_shadow(init_level4_pgt) call in x86_64_start_kernel(). Make it static, and call it from kasan_early_init() only. ------------------------------------------------------ From: Andrey Ryabinin <[email protected]> Subject: [PATCH] x86_64: remove not needed clear_page for init_level4_page Commit 8170e6bed465 ("x86, 64bit: Use a #PF handler to materialize early mappings on demand") introduced clear_page(init_level4_pgt); call in x86_64_start_kernel(). However, this clear_page is useless because init_level4_page already filled with zeroes in head_64.S Commit message in 8170e6bed465 says that this clear_page() was dropped in v7, but it accidentally reappeared in later versions of that patchset. Signed-off-by: Andrey Ryabinin <[email protected]> --- arch/x86/kernel/head64.c | 1 - 1 file changed, 1 deletion(-) diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c index 5a46681..6a6eefd 100644 --- a/arch/x86/kernel/head64.c +++ b/arch/x86/kernel/head64.c @@ -177,7 +177,6 @@ asmlinkage __visible void __init x86_64_start_kernel(char * real_mode_data) */ load_ucode_bsp(); - clear_page(init_level4_pgt); /* set init_level4_pgt kernel high mapping*/ init_level4_pgt[511] = early_level4_pgt[511]; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
