Backported version of upstream commit 4dbd633e90e0

[Michael Kelley <mikelley@microsoft.com>]

Here's a backported version of upstream commit ID
4dbd6a3e90e03130973688fd79e19425f720d999 that will work with
5.4, 4.19, 4.14, and 4.9.

Michael

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6f2e8eba629d29ffae0fc71c0cfd6b694ac4a5ec Mon Sep 17 00:00:00 2001
From: Michael Kelley <mikelley@microsoft.com>
Date: Sun, 4 Dec 2022 13:52:01 -0800
Subject: [PATCH v4 1/1] x86/ioremap: Fix page aligned size calculation in
 __ioremap_caller()

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>
---
 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 ecae9ac..696fd6f 100644
--- a/arch/x86/mm/ioremap.c
+++ b/arch/x86/mm/ioremap.c
@@ -126,9 +126,15 @@ 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) {
-- 
1.8.3.1