diff options
Diffstat (limited to 'include/zero_page.h')
-rw-r--r-- | include/zero_page.h | 54 |
1 files changed, 54 insertions, 0 deletions
diff --git a/include/zero_page.h b/include/zero_page.h new file mode 100644 index 0000000000..ad6861f240 --- /dev/null +++ b/include/zero_page.h @@ -0,0 +1,54 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +#ifndef __ZERO_PAGE_H +#define __ZERO_PAGE_H + +#include <common.h> + +#if defined CONFIG_ARCH_HAS_ZERO_PAGE + +/* + * zero_page_faulting - fault when accessing the zero page + */ +void zero_page_faulting(void); + +/* + * zero_page_access - allow accesses to the zero page + * + * Disable the null pointer trap on the zero page if access to the zero page + * is actually required. Disable the trap with care and re-enable it + * immediately after the access to properly trap null pointers. + */ +void zero_page_access(void); + +#else + +static inline void zero_page_faulting(void) +{ +} + +static inline void zero_page_access(void) +{ +} + +#endif + +static inline bool zero_page_contains(unsigned long addr) +{ + return addr < PAGE_SIZE; +} + +/* + * zero_page_memcpy - copy to or from an address located in the zero page + */ +static inline void *zero_page_memcpy(void *dest, const void *src, size_t count) +{ + void *ret; + + zero_page_access(); + ret = memcpy(dest, src, count); + zero_page_faulting(); + + return ret; +} + +#endif /* __ZERO_PAGE_H */ |