linux-kernel - [PATCH] arm64/kernel: Fix range on invalidating dcache for boot page tables

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Date:   Fri, 24 Apr 2020 15:02:30 +1000
From:   Gavin Shan <gshan@...hat.com>
To:     linux-arm-kernel@...ts.infradead.org
Cc:     linux-kernel@...r.kernel.org, catalin.marinas@....com,
        will@...nel.org, steve.capper@....com, broonie@...nel.org,
        mark.rutland@....com, shan.gavin@...il.com
Subject: [PATCH] arm64/kernel: Fix range on invalidating dcache for boot page tables

The MMU is disabled when __create_page_tables() is called. The data
cache corresponding to these two page tables, which are tracked by
@idmap_pg_dir and @init_pg_dir, is invalidated after the page tables
are populated. However, the wrong or inappropriate size have been used
and more data cache are invalidated than it need.

This fixes the issue by invalidating the data cache for these two
page tables separately as they aren't necessarily physically adjacent.

Signed-off-by: Gavin Shan <gshan@...hat.com>
---
 arch/arm64/kernel/head.S | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
index 57a91032b4c2..66947873c9e7 100644
--- a/arch/arm64/kernel/head.S
+++ b/arch/arm64/kernel/head.S
@@ -398,6 +398,10 @@ SYM_FUNC_START_LOCAL(__create_page_tables)
 	 * tables again to remove any speculatively loaded cache lines.
 	 */
 	adrp	x0, idmap_pg_dir
+	mov	x1, #IDMAP_DIR_SIZE
+	dmb	sy
+	bl	__inval_dcache_area
+	adrp	x0, init_pg_dir
 	adrp	x1, init_pg_end
 	sub	x1, x1, x0
 	dmb	sy
-- 
2.23.0