This is a note to let you know that I've just added the patch titled
s390/pageattr: Implement missing kernel_page_present()
to the 6.11-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
s390-pageattr-implement-missing-kernel_page_present.patch
and it can be found in the queue-6.11 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 055eb82f0a70ce058d02633d767e53296892ee12
Author: Heiko Carstens <hca@xxxxxxxxxxxxx>
Date: Fri Oct 18 14:26:23 2024 +0200
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@xxxxxxxxxxxxx>
Closes: https://lore.kernel.org/all/045de961-ac69-40cc-b141-ab70ec9377ec@xxxxxxxxxxxxx
Fixes: 0490d6d7ba0a ("s390/mm: enable ARCH_HAS_SET_DIRECT_MAP")
Reviewed-by: Alexander Gordeev <agordeev@xxxxxxxxxxxxx>
Signed-off-by: Heiko Carstens <hca@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/arch/s390/include/asm/set_memory.h b/arch/s390/include/asm/set_memory.h
index 06fbabe2f66c9..cb4cc0f59012f 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 5f805ad42d4c3..aec9eb16b6f7b 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)
