linux-kernel - [PATCH 3.16 200/305] xtensa: fix boot parameters address translation

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Message-ID: <lsq.1549201508.176505087@decadent.org.uk>
Date:   Sun, 03 Feb 2019 14:45:08 +0100
From:   Ben Hutchings <ben@...adent.org.uk>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC:     akpm@...ux-foundation.org, Denis Kirjanov <kda@...ux-powerpc.org>,
        "Max Filippov" <jcmvbkbc@...il.com>
Subject: [PATCH 3.16 200/305] xtensa: fix boot parameters address translation

3.16.63-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Max Filippov <jcmvbkbc@...il.com>

commit 40dc948f234b73497c3278875eb08a01d5854d3f upstream.

The bootloader may pass physical address of the boot parameters structure
to the MMUv3 kernel in the register a2. Code in the _SetupMMU block in
the arch/xtensa/kernel/head.S is supposed to map that physical address to
the virtual address in the configured virtual memory layout.

This code haven't been updated when additional 256+256 and 512+512
memory layouts were introduced and it may produce wrong addresses when
used with these layouts.

Signed-off-by: Max Filippov <jcmvbkbc@...il.com>
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
 arch/xtensa/kernel/head.S | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

--- a/arch/xtensa/kernel/head.S
+++ b/arch/xtensa/kernel/head.S
@@ -88,9 +88,12 @@ _SetupMMU:
 	initialize_mmu
 #if defined(CONFIG_MMU) && XCHAL_HAVE_PTP_MMU && XCHAL_HAVE_SPANNING_WAY
 	rsr	a2, excsave1
-	movi	a3, 0x08000000
+	movi	a3, XCHAL_KSEG_PADDR
+	bltu	a2, a3, 1f
+	sub	a2, a2, a3
+	movi	a3, XCHAL_KSEG_SIZE
 	bgeu	a2, a3, 1f
-	movi	a3, 0xd0000000
+	movi	a3, XCHAL_KSEG_CACHED_VADDR
 	add	a2, a2, a3
 	wsr	a2, excsave1
 1: