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authorGreg Ungerer <gerg@linux-m68k.org>2022-04-20 23:27:47 +1000
committerGreg Ungerer <gerg@linux-m68k.org>2022-05-16 13:18:30 +1000
commitdc068f46217970d9516f16cd37972a01d50dc055 (patch)
tree90d1fce067e04440fd9eff6ea5ae83c18546524d /arch/m68k
parent42226c989789d8da4af1de0c31070c96726d990c (diff)
m68knommu: set ZERO_PAGE() to the allocated zeroed page
The non-MMU m68k pagetable ZERO_PAGE() macro is being set to the somewhat non-sensical value of "virt_to_page(0)". The zeroth page is not in any way guaranteed to be a page full of "0". So the result is that ZERO_PAGE() will almost certainly contain random values. We already allocate a real "empty_zero_page" in the mm setup code shared between MMU m68k and non-MMU m68k. It is just not hooked up to the ZERO_PAGE() macro for the non-MMU m68k case. Fix ZERO_PAGE() to use the allocated "empty_zero_page" pointer. I am not aware of any specific issues caused by the old code. Link: https://lore.kernel.org/linux-m68k/2a462b23-5b8e-bbf4-ec7d-778434a3b9d7@google.com/T/#t Reported-by: Hugh Dickens <hughd@google.com> Signed-off-by: Greg Ungerer <gerg@linux-m68k.org>
Diffstat (limited to 'arch/m68k')
-rw-r--r--arch/m68k/include/asm/pgtable_no.h3
1 files changed, 2 insertions, 1 deletions
diff --git a/arch/m68k/include/asm/pgtable_no.h b/arch/m68k/include/asm/pgtable_no.h
index 87151d67d91e..bce5ca56c388 100644
--- a/arch/m68k/include/asm/pgtable_no.h
+++ b/arch/m68k/include/asm/pgtable_no.h
@@ -42,7 +42,8 @@ extern void paging_init(void);
* ZERO_PAGE is a global shared page that is always zero: used
* for zero-mapped memory areas etc..
*/
-#define ZERO_PAGE(vaddr) (virt_to_page(0))
+extern void *empty_zero_page;
+#define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page))
/*
* All 32bit addresses are effectively valid for vmalloc...