[PATCH 3/4] x86/boot/compressed/64: Fix trampoline page table address calculation

From: Kirill A. Shutemov
Date: Wed May 16 2018 - 03:32:02 EST


Hugh noticied that I calculate address of trampoline page table wrong in
cleanup_trampoline(). TRAMPOLINE_32BIT_PGTABLE_OFFSET has to be divided
by sizeof(unsigned long) since trampoline_32bit is unsigned long
pointer.

TRAMPOLINE_32BIT_PGTABLE_OFFSET is zero so the bug doesn't have a
visible effect.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Reported-by: Hugh Dickins <hughd@xxxxxxxxxx>
Fixes: e9d0e6330eb8 ("x86/boot/compressed/64: Prepare new top-level page table for trampoline")
---
arch/x86/boot/compressed/pgtable_64.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/boot/compressed/pgtable_64.c b/arch/x86/boot/compressed/pgtable_64.c
index a362fa0b849c..23707e1da1ff 100644
--- a/arch/x86/boot/compressed/pgtable_64.c
+++ b/arch/x86/boot/compressed/pgtable_64.c
@@ -130,7 +130,7 @@ void cleanup_trampoline(void *pgtable)
{
void *trampoline_pgtable;

- trampoline_pgtable = trampoline_32bit + TRAMPOLINE_32BIT_PGTABLE_OFFSET;
+ trampoline_pgtable = trampoline_32bit + TRAMPOLINE_32BIT_PGTABLE_OFFSET / sizeof(unsigned long);

/*
* Move the top level page table out of trampoline memory,
--
2.17.0