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| author | Wei-Lin Chang <weilin.chang@arm.com> | 2026-08-14 23:24:57 +0100 |
|---|---|---|
| committer | Will Deacon <will@kernel.org> | 2026-08-24 13:31:19 +0000 |
| commit | 902caade3cfd60f99bf71b355e7c86344bd831e5 (patch) | |
| tree | 1426fcde91f5cf91b0baecbdc3d27f9851ada0c2 | |
| parent | 26b77009ee74f6122a067a4f9926ff6e09fffb94 (diff) | |
| download | linux-902caade3cfd60f99bf71b355e7c86344bd831e5.tar.gz linux-902caade3cfd60f99bf71b355e7c86344bd831e5.zip | |
arm64: ptdump: Make note_page_flush() range aware
note_page_flush() calls note_page() with addr == 0 and level == -1 to
dump the last row of a ptdump. addr == 0 (1 << 64 wrapped around)
renders a huge region with enormous size for address spaces with
IA bits < 64. For example the stage-2 page tables and the EFI runtime
page table.
More importantly, the last region of the address space and everything
after the address space up to 1 << 64 are merged into one row of
output. If the last region within the address space is valid, it will
appear to remain valid up to 1 << 64 with the same attributes.
Currently only the EFI runtime ptdump is affected by this, but KVM will
soon fix its stage-2 ptdump by using note_page_flush(). Here is an
example of an EFI runtime ptdump (last row):
0x0000008000000000-0x0000000000000000 17179868672G PGD
With this patch:
0x0000008000000000-0x0001000000000000 261632G PGD
To fix this, cache the end address of a ptdump in ptdump_pg_state so
note_page_flush() can call the final note_page() with the correct end
address.
Fixes: 9d80448ac92b ("efi/arm64: Add debugfs node to dump UEFI runtime page tables")
Signed-off-by: Wei-Lin Chang <weilin.chang@arm.com>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Will Deacon <will@kernel.org>
| -rw-r--r-- | arch/arm64/include/asm/ptdump.h | 2 | ||||
| -rw-r--r-- | arch/arm64/mm/ptdump.c | 14 |
2 files changed, 15 insertions, 1 deletions
diff --git a/arch/arm64/include/asm/ptdump.h b/arch/arm64/include/asm/ptdump.h index 5b374a6ab34a..1b743de7d89e 100644 --- a/arch/arm64/include/asm/ptdump.h +++ b/arch/arm64/include/asm/ptdump.h @@ -52,6 +52,8 @@ struct ptdump_pg_state { const struct addr_marker *marker; const struct mm_struct *mm; unsigned long start_address; + /* exclusive end, ULONG_MAX represents an end at 1 << 64 */ + unsigned long end_address; int level; ptval_t current_prot; bool check_wx; diff --git a/arch/arm64/mm/ptdump.c b/arch/arm64/mm/ptdump.c index 1c20144700d7..eab400e744d9 100644 --- a/arch/arm64/mm/ptdump.c +++ b/arch/arm64/mm/ptdump.c @@ -278,9 +278,19 @@ void note_page_pgd(struct ptdump_state *pt_st, unsigned long addr, pgd_t pgd) void note_page_flush(struct ptdump_state *pt_st) { + struct ptdump_pg_state *st = container_of(pt_st, struct ptdump_pg_state, ptdump); + unsigned long end = st->end_address; pte_t pte_zero = {0}; - note_page(pt_st, 0, -1, pte_val(pte_zero)); + /* + * Address spaces that end at 1 << 64 have end_address == ULONG_MAX, + * but note_page() expects the exclusive end. In this case adjust end + * to the wraparound value 0. + */ + if (end == ULONG_MAX) + end = 0; + + note_page(pt_st, end, -1, pte_val(pte_zero)); } static void arm64_ptdump_walk_pgd(struct ptdump_state *st, struct mm_struct *mm) @@ -303,6 +313,7 @@ void ptdump_walk(struct seq_file *s, struct ptdump_info *info) .marker = info->markers, .mm = info->mm, .pg_level = &kernel_pg_levels[0], + .end_address = end, .level = -1, .ptdump = { .note_page_pte = note_page_pte, @@ -344,6 +355,7 @@ bool ptdump_check_wx(void) { -1, NULL}, }, .pg_level = &kernel_pg_levels[0], + .end_address = ~0UL, .level = -1, .check_wx = true, .ptdump = { |