diff options
| author | Heiko Carstens <[email protected]> | 2024-10-18 14:26:23 +0200 |
|---|---|---|
| committer | Heiko Carstens <[email protected]> | 2024-10-25 16:03:23 +0200 |
| commit | 2835f8bf5530750c3381166005934f996a83ad05 (patch) | |
| tree | a83264912660044ccd0822b1da74619f720dc7af /arch/s390/mm/pageattr.c | |
| parent | e6ebf0d6514bd4438f43fe8926723cf807355b7e (diff) | |
s390/pageattr: Implement missing kernel_page_present()
kernel_page_present() was intentionally not implemented when adding
ARCH_HAS_SET_DIRECT_MAP support, since it was only used for suspend/resume
which is not supported anymore on s390.
A new bpf use case led to a compile error specific to s390. Even though
this specific use case went away implement kernel_page_present(), so that
the API is complete and potential future users won't run into this problem.
Reported-by: Daniel Borkmann <[email protected]>
Closes: https://lore.kernel.org/all/[email protected]
Fixes: 0490d6d7ba0a ("s390/mm: enable ARCH_HAS_SET_DIRECT_MAP")
Reviewed-by: Alexander Gordeev <[email protected]>
Signed-off-by: Heiko Carstens <[email protected]>
Diffstat (limited to 'arch/s390/mm/pageattr.c')
| -rw-r--r-- | arch/s390/mm/pageattr.c | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/arch/s390/mm/pageattr.c b/arch/s390/mm/pageattr.c index 5f805ad42d4c..aec9eb16b6f7 100644 --- a/arch/s390/mm/pageattr.c +++ b/arch/s390/mm/pageattr.c @@ -406,6 +406,21 @@ 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" + " ipm %[cc]\n" + : [cc] "=d" (cc), [addr] "+a" (addr) + : + : "cc"); + return (cc >> 28) == 0; +} + #if defined(CONFIG_DEBUG_PAGEALLOC) || defined(CONFIG_KFENCE) static void ipte_range(pte_t *pte, unsigned long address, int nr) |