[PATCH 4.9 33/83] xtensa: fix boot parameters address translation

Greg Kroah-Hartman
2018-11-19T16:55:20Z

From: Max Filippov <jcmvbkbc@gmail.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.

Cc: stable@vger.kernel.org
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
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: