[PATCH 4.14 75/77] x86/ioremap: Fix page aligned size calculation in __ioremap_caller()

Greg Kroah-Hartman
2022-12-05T19:17:52Z

From: Michael Kelley <mikelley@microsoft.com>

[ Upstream commit 4dbd6a3e90e03130973688fd79e19425f720d999 ]

Current code re-calculates the size after aligning the starting and
ending physical addresses on a page boundary. But the re-calculation
also embeds the masking of high order bits that exceed the size of
the physical address space (via PHYSICAL_PAGE_MASK). If the masking
removes any high order bits, the size calculation results in a huge
value that is likely to immediately fail.

Fix this by re-calculating the page-aligned size first. Then mask any
high order bits using PHYSICAL_PAGE_MASK.

Fixes: ffa71f33a820 ("x86, ioremap: Fix incorrect physical address handling in PAE mode")
Signed-off-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: <stable@kernel.org>
Link: https://lore.kernel.org/r/1668624097-14884-2-git-send-email-mikelley@microsoft.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/x86/mm/ioremap.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
index 3faf9667cc40..13ac4bc1a2dc 100644
--- a/arch/x86/mm/ioremap.c
+++ b/arch/x86/mm/ioremap.c
@@ -124,9 +124,15 @@ static void __iomem *__ioremap_caller(resource_size_t phys_addr,
* Mappings have to be page-aligned
*/
offset = phys_addr & ~PAGE_MASK;
- phys_addr &= PHYSICAL_PAGE_MASK;
+ phys_addr &= PAGE_MASK;
size = PAGE_ALIGN(last_addr+1) - phys_addr;

+ /*
+ * Mask out any bits not part of the actual physical
+ * address, like memory encryption bits.
+ */
+ phys_addr &= PHYSICAL_PAGE_MASK;
+
retval = reserve_memtype(phys_addr, (u64)phys_addr + size,
pcm, &new_pcm);
if (retval) {
--
2.35.1