From: "Pierre-Clément Tosi" <ptosi@google.com>
To: u-boot@lists.denx.de
Cc: Marc Zyngier <maz@kernel.org>, Fabio Estevam <festevam@gmail.com>,
Tom Rini <trini@konsulko.com>
Subject: [PATCH] arm64: Fix map_range() not splitting mapped blocks
Date: Mon, 18 Mar 2024 19:35:49 +0000 [thread overview]
Message-ID: <43haokus4jdxguk4arig5tsqcgq2wbezwpbj7oti6pdkvrfual@wa7vz2iypcv5> (raw)
The implementation of map_range() creates the requested mapping by
walking the page tables, iterating over multiple PTEs and/or descending
into existing table mappings as needed. When doing so, it assumes any
pre-existing valid PTE to be a table mapping. This assumption is wrong
if the platform code attempts to successively map two overlapping ranges
where the latter intersects a block mapping created for the former.
As a result, map_range() treats the existing block mapping as a table
mapping and descends into it i.e. starts interpreting the
previously-mapped range as an array of PTEs, writing to them and
potentially even descending further (extra fun with MMIO ranges!).
Instead, pass any valid non-table mapping to split_block(), which
ensures that it actually was a block mapping (calls panic() otherwise)
before splitting it.
Fixes: 41e2787f5ec4 ("arm64: Reduce add_map() complexity")
Signed-off-by: Pierre-Clément Tosi <ptosi@google.com>
---
arch/arm/cpu/armv8/cache_v8.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/arch/arm/cpu/armv8/cache_v8.c b/arch/arm/cpu/armv8/cache_v8.c
index 697334086f..57d06f0575 100644
--- a/arch/arm/cpu/armv8/cache_v8.c
+++ b/arch/arm/cpu/armv8/cache_v8.c
@@ -326,6 +326,8 @@ static void map_range(u64 virt, u64 phys, u64 size, int level,
/* Going one level down */
if (pte_type(&table[i]) == PTE_TYPE_FAULT)
set_pte_table(&table[i], create_table());
+ else if (pte_type(&table[i]) != PTE_TYPE_TABLE)
+ split_block(&table[i], level);
next_table = (u64 *)(table[i] & GENMASK_ULL(47, PAGE_SHIFT));
next_size = min(map_size - (virt & (map_size - 1)), size);
--
2.44.0.291.gc1ea87d7ee-goog
--
Pierre
next reply other threads:[~2024-03-18 19:36 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-18 19:35 Pierre-Clément Tosi [this message]
2024-03-18 19:46 ` [PATCH] arm64: Fix map_range() not splitting mapped blocks Fabio Estevam
2024-03-19 9:43 ` Marc Zyngier
2024-03-19 11:39 ` Pierre-Clément Tosi
2024-03-19 12:13 ` Fabio Estevam
2024-03-19 12:39 ` Pierre-Clément Tosi
2024-03-22 19:31 ` Fabio Estevam
2024-03-22 19:33 ` Fabio Estevam
2024-03-23 14:34 ` Tom Rini
2024-03-25 20:37 ` Hiago De Franco
2024-03-30 20:03 ` Fabio Estevam
2024-04-10 13:31 ` Fabio Estevam
2024-03-26 9:21 ` Marc Zyngier
2024-04-10 17:43 ` Tom Rini
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