x86/boot/compressed/64: Fix trampoline page table address calculation

Hugh noticied that we calculate the address of the trampoline page table
incorrectly in cleanup_trampoline().

TRAMPOLINE_32BIT_PGTABLE_OFFSET has to be divided by sizeof(unsigned long),
since trampoline_32bit is an 'unsigned long' pointer.

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

Reported-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Fixes: e9d0e6330eb8 ("x86/boot/compressed/64: Prepare new top-level page table for trampoline")
Link: http://lkml.kernel.org/r/20180518103528.59260-2-kirill.shutemov@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/arch/x86/boot/compressed/pgtable_64.c b/arch/x86/boot/compressed/pgtable_64.c
index a362fa0b849c70c3da1e290ea9bf536272ca62c7..23707e1da1ff8d472ad7dc766e3d1018a995a87a 100644 (file)
--- 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,