lkml.org 
[lkml]   [2022]   [Nov]   [22]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH v4 1/1] x86/ioremap: Fix page aligned size calculation in __ioremap_caller()
Date
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")
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Michael Kelley <mikelley@microsoft.com>
---

This patch was previously Patch 1 of a larger series[1]. Breaking
it out separately per discussion with Dave Hansen and Boris Petkov.

[1] https://lore.kernel.org/linux-hyperv/1668624097-14884-1-git-send-email-mikelley@microsoft.com/

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 78c5bc6..6453fba 100644
--- a/arch/x86/mm/ioremap.c
+++ b/arch/x86/mm/ioremap.c
@@ -217,9 +217,15 @@ static void __ioremap_check_mem(resource_size_t addr, unsigned long size,
* 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 = memtype_reserve(phys_addr, (u64)phys_addr + size,
pcm, &new_pcm);
if (retval) {
--
1.8.3.1
\
 
 \ /
  Last update: 2022-11-22 18:43    [W:0.054 / U:0.424 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site