diff options
Diffstat (limited to 'arch/s390/mm/pageattr.c')
| -rw-r--r-- | arch/s390/mm/pageattr.c | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/arch/s390/mm/pageattr.c b/arch/s390/mm/pageattr.c index 5f805ad42d4c..4a0f422cfeb6 100644 --- a/arch/s390/mm/pageattr.c +++ b/arch/s390/mm/pageattr.c @@ -12,6 +12,7 @@ #include <asm/pgalloc.h> #include <asm/kfence.h> #include <asm/page.h> +#include <asm/asm.h> #include <asm/set_memory.h> static inline unsigned long sske_frame(unsigned long addr, unsigned char skey) @@ -406,6 +407,21 @@ int set_direct_map_default_noflush(struct page *page) return __set_memory((unsigned long)page_to_virt(page), 1, SET_MEMORY_DEF); } +bool kernel_page_present(struct page *page) +{ + unsigned long addr; + unsigned int cc; + + addr = (unsigned long)page_address(page); + asm volatile( + " lra %[addr],0(%[addr])\n" + CC_IPM(cc) + : CC_OUT(cc, cc), [addr] "+a" (addr) + : + : CC_CLOBBER); + return CC_TRANSFORM(cc) == 0; +} + #if defined(CONFIG_DEBUG_PAGEALLOC) || defined(CONFIG_KFENCE) static void ipte_range(pte_t *pte, unsigned long address, int nr) |