Hi Albert,
Le 15/10/2014 00:11, Albert ARIBAUD a écrit :
Hi Georges,
On Tue, 14 Oct 2014 22:02:00 +0200, Georges Savoundararadj
<savou...@gmail.com> wrote:
Hi Albert,
Hi Masahiro,
(putting Masahiro in Cc: just in case)
As my issue is related to Kconfig, I would like you to give me your
opinions.
Le 11/10/2014 12:47, Albert ARIBAUD a écrit :
Hi Georges,
On Sat, 27 Sep 2014 21:48:10 +0200, Georges Savoundararadj
<savou...@gmail.com> wrote:
This commit relocates the exception vectors.
As ARM1176 and ARMv7 have the security extensions, it uses VBAR. For
the other ARM processors, it copies the relocated exception vectors to
the correct address: 0x00000000 or 0xFFFF0000.
Signed-off-by: Georges Savoundararadj <savou...@gmail.com>
Cc: Albert Aribaud <albert.u.b...@aribaud.net>
Cc: Tom Warren <twar...@nvidia.com>
---
This patch needs some tests because it impacts many boards. I have
tested it with my raspberry pi in the two cases: using VBAR and
using the copied exception vectors.
Changes in v2:
- Relocate exception vectors also on processors which do not support
security extensions
- Reword the commit message
arch/arm/cpu/armv7/start.S | 6 ------
arch/arm/lib/relocate.S | 30 ++++++++++++++++++++++++++++++
2 files changed, 30 insertions(+), 6 deletions(-)
diff --git a/arch/arm/cpu/armv7/start.S b/arch/arm/cpu/armv7/start.S
index fedd7c8..fdc05b9 100644
--- a/arch/arm/cpu/armv7/start.S
+++ b/arch/arm/cpu/armv7/start.S
@@ -81,12 +81,6 @@ ENTRY(c_runtime_cpu_setup)
mcr p15, 0, r0, c7, c10, 4 @ DSB
mcr p15, 0, r0, c7, c5, 4 @ ISB
#endif
-/*
- * Move vector table
- */
- /* Set vector address in CP15 VBAR register */
- ldr r0, =_start
- mcr p15, 0, r0, c12, c0, 0 @Set VBAR
bx lr
diff --git a/arch/arm/lib/relocate.S b/arch/arm/lib/relocate.S
index 8035251..88a478e 100644
--- a/arch/arm/lib/relocate.S
+++ b/arch/arm/lib/relocate.S
@@ -6,6 +6,8 @@
* SPDX-License-Identifier: GPL-2.0+
*/
+#include <asm-offsets.h>
+#include <config.h>
#include <linux/linkage.h>
/*
@@ -52,6 +54,34 @@ fixnext:
cmp r2, r3
blo fixloop
+ /*
+ * Relocate the exception vectors
+ */
+#if (defined(CONFIG_ARM1176) || defined(CONFIG_ARMV7))
I would prefer a single CONFIG_HAS_VBAR symbol defined through
Kconfig.
1)
Actually, there is no Kconfig entry such as "config ARM1176" nor "config
ARMV7" in U-Boot,
unlike in Linux (arch/arm/mm/Kconfig).
If there were such entries, we would simply do like the following (in
arch/arm/Kconfig):
config HAS_VBAR
bool
config ARM1176
select HAS_VBAR
config ARMV7
select HAS_VBAR
Should we go in this direction?
It is the cleanest way to use Kconfig but it requires some work in order
to convert all
"#define CONFIG_<cpu>" into Kconfig entries.
2)
Otherwise, we can insert a "select HAS_VBAR" in all boards that have a
ARM1176 or a ARMv7
processor in arch/arm/Kconfig. It is not logical but this is what has
been done with the Kconfig
entry ARM64. And, it does not require much change.
3)
The last thing we can do is as follows:
config HAS_VBAR
bool
depends on SYS_CPU = "arm1176" || SYS_CPU = "armv7"
default y
CONFIG_HAS_VBAR will be defined if SYS_CPU are arm1176 or armv7. It does
not require much
change as well but, I think, it is bad code.
What do you think is the best way to introduce CONFIG_HAS_VBAR symbol?
(1, 2 or 3)
I believe you have already sorted the options in order of decreasing
'quality' -- 1 being the best option, and 3 being the worst... Indeed
option 1 would be the best and cleanest, and it could possibly open the
way for other per-CPU options.
We could try and limit the effort to converting only ARM1176 and ARMV7
and leaving other CONFIG_<cpu> #define'd until some later point in the
future, but experience shows that such half-hearted attempts are never
completed.
Amicalement,
I am currently trying to implement solution 1. only for ARM1176 and
ARMV7 but I wonder
if this work worth the effort just for one CPU feature.
Do you expect more CPU feature like HAS_VBAR coming in the future?
I add the following lines in arch/arm/Kconfig:
config HAS_VBAR
bool
config ARM1176
bool
select HAS_VBAR
config ARMV7
bool
select HAS_VBAR
config SYS_CPU
default "arm1176" if ARM1176
default "armv7" if ARMV7
Then, in the same file, under each "config TARGET_<board>", I add
"select ARM1176" or "select ARMV7".
Also, I delete the Kconfig entries "config SYS_CPU" in all Kconfig of
*all* boards that use ARM1176 and ARMV7.
Actually, I find the change quite big. What do you think about this
implementation?
Should I continue in this direction?
Regards,
Georges
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