Hi Georges, On Mon, 20 Oct 2014 23:08:30 +0200, Georges Savoundararadj <savou...@gmail.com> wrote:
> 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? This looks like the right way to me (even if ideally I would prefer that SYS_CPU be deduced from the SYS_SOC defined in the boards' Kconfig files rather than added to them). Hopefully you can devise a sed, awk o perl script to do the change without too much manual effort? Incidentally, this raises a question which Masahiro can probably answer. In arch/arm/Kconfig, every ARM board is referred to twice: - once in a "config TARGET_<board>" block; - once in a "source board[/<maker>]/<board>/Kconfig directive. Would it be possible to move each "TARGET_<board>" block from arch/arm/Kconfig to the corresponding board[/<maker>]/<board>/Kconfig and only keep the "source" directives in arch/arm/Kconfig? (and then, I'd *really* like a way to source all ARM-based boards in a few lines, e.g. source /board/*/Kconfig + source board/*/*/Kconfig) It would be nice if all Kconfig settings for a given board were found in the board's Kconfig. > Regards, > > Georges Amicalement, -- Albert. _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
