[PATCH] arm64: Fix 5-level paging support in kexec/hibernate trampoline
Ard Biesheuvel
ardb+git at google.com
Fri Jan 10 09:51:46 PST 2025
From: Ard Biesheuvel <ardb at kernel.org>
Add the missing code to allocate P4D level page tables when cloning the
the kernel page tables. This fixes a crash that may be observed when
attempting to resume from hibernation on an LPA2 capable system with 4k
pages, which therefore uses 5 levels of paging.
Presumably, kexec is equally affected.
Signed-off-by: Ard Biesheuvel <ardb at kernel.org>
---
arch/arm64/mm/trans_pgd.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/arch/arm64/mm/trans_pgd.c b/arch/arm64/mm/trans_pgd.c
index 0f7b484cb2ff..84594f02f780 100644
--- a/arch/arm64/mm/trans_pgd.c
+++ b/arch/arm64/mm/trans_pgd.c
@@ -162,6 +162,13 @@ static int copy_p4d(struct trans_pgd_info *info, pgd_t *dst_pgdp,
unsigned long next;
unsigned long addr = start;
+ if (pgd_none(READ_ONCE(*dst_pgdp))) {
+ dst_p4dp = trans_alloc(info);
+ if (!dst_p4dp)
+ return -ENOMEM;
+ pgd_populate(NULL, dst_pgdp, dst_p4dp);
+ }
+
dst_p4dp = p4d_offset(dst_pgdp, start);
src_p4dp = p4d_offset(src_pgdp, start);
do {
--
2.47.1.688.g23fc6f90ad-goog
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