linux-kernel - [PATCH v2] arm/memremap: fix arch_memremap_can_ram

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Message-ID: <20250414142140.131756-1-ross.stutterheim@garmin.com>
Date: Mon, 14 Apr 2025 09:21:40 -0500
From: Ross Stutterheim <ross.stutterheim@...min.com>
To: <linux-arm-kernel@...ts.infradead.org>, <linux-kernel@...r.kernel.org>
CC: Russell King <linux@...linux.org.uk>, Mike Rapoport <rppt@...ux.ibm.com>,
        <ross.stutterheim@...min.com>, <ross.sweng@...il.com>
Subject: [PATCH v2] arm/memremap: fix arch_memremap_can_ram_remap()

commit 260364d112bc ("arm[64]/memremap: don't abuse pfn_valid() to ensure
presence of linear map") added the definition of
arch_memremap_can_ram_remap() for arm[64] specific filtering of what pages
can be used from the linear mapping. memblock_is_map_memory() was called
with the pfn of the address given to arch_memremap_can_ram_remap();
however, memblock_is_map_memory() expects to be given an address for arm,
not a pfn.

This results in calls to memremap() returning a newly mapped area when
it should return an address in the existing linear mapping.

Fix this by removing the address to pfn translation and pass the
address directly.

Fixes: 260364d112bc ("arm[64]/memremap: don't abuse pfn_valid() to ensure presence of linear map")
Signed-off-by: Ross Stutterheim <ross.stutterheim@...min.com>
---
 arch/arm/mm/ioremap.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/arch/arm/mm/ioremap.c b/arch/arm/mm/ioremap.c
index 748698e91a4b..27e64f782cb3 100644
--- a/arch/arm/mm/ioremap.c
+++ b/arch/arm/mm/ioremap.c
@@ -515,7 +515,5 @@ void __init early_ioremap_init(void)
 bool arch_memremap_can_ram_remap(resource_size_t offset, size_t size,
 				 unsigned long flags)
 {
-	unsigned long pfn = PHYS_PFN(offset);
-
-	return memblock_is_map_memory(pfn);
+	return memblock_is_map_memory(offset);
 }
-- 
2.49.0