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| author | Heiko Carstens <hca@linux.ibm.com> | 2024-10-18 14:26:23 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2024-12-09 10:31:43 +0100 |
| commit | aa6e32c654fcbcd384c2259e0fe54f67f442c7e9 (patch) | |
| tree | 2ba73d6154b98704bff7836cd828480c2b910dd5 /arch | |
| parent | a1dc0428c05a5a0073d78eeaa3d594ded6ada5c7 (diff) | |
| download | linux-aa6e32c654fcbcd384c2259e0fe54f67f442c7e9.tar.gz linux-aa6e32c654fcbcd384c2259e0fe54f67f442c7e9.tar.bz2 linux-aa6e32c654fcbcd384c2259e0fe54f67f442c7e9.zip | |
s390/pageattr: Implement missing kernel_page_present()
[ Upstream commit 2835f8bf5530750c3381166005934f996a83ad05 ]
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 <daniel@iogearbox.net>
Closes: https://lore.kernel.org/all/045de961-ac69-40cc-b141-ab70ec9377ec@iogearbox.net
Fixes: 0490d6d7ba0a ("s390/mm: enable ARCH_HAS_SET_DIRECT_MAP")
Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/s390/include/asm/set_memory.h | 1 | ||||
| -rw-r--r-- | arch/s390/mm/pageattr.c | 15 |
2 files changed, 16 insertions, 0 deletions
diff --git a/arch/s390/include/asm/set_memory.h b/arch/s390/include/asm/set_memory.h index 06fbabe2f66c..cb4cc0f59012 100644 --- a/arch/s390/include/asm/set_memory.h +++ b/arch/s390/include/asm/set_memory.h @@ -62,5 +62,6 @@ __SET_MEMORY_FUNC(set_memory_4k, SET_MEMORY_4K) int set_direct_map_invalid_noflush(struct page *page); int set_direct_map_default_noflush(struct page *page); +bool kernel_page_present(struct page *page); #endif diff --git a/arch/s390/mm/pageattr.c b/arch/s390/mm/pageattr.c index 441f654d048d..44271835c97e 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) |