From mboxrd@z Thu Jan 1 00:00:00 1970 From: santosh.shilimkar@ti.com (Santosh Shilimkar) Date: Tue, 25 Jun 2013 10:40:57 -0400 Subject: [PATCH] ARM: keystone: remove hand-coded smc instruction In-Reply-To: <20130625143211.GE2327@linaro.org> References: <201306212228.29717.arnd@arndb.de> <201306212313.16771.arnd@arndb.de> <51C4C3B4.2050508@ti.com> <201306212341.08579.arnd@arndb.de> <51C4D9B7.5010109@ti.com> <20130625141332.GC2327@linaro.org> <51C9A8BF.9040602@ti.com> <20130625143211.GE2327@linaro.org> Message-ID: <51C9ABF9.1010902@ti.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Tuesday 25 June 2013 10:32 AM, Dave Martin wrote: > On Tue, Jun 25, 2013 at 10:27:11AM -0400, Santosh Shilimkar wrote: >> On Tuesday 25 June 2013 10:13 AM, Dave Martin wrote: >>> On Fri, Jun 21, 2013 at 06:54:47PM -0400, Santosh Shilimkar wrote: >>>> On Friday 21 June 2013 05:41 PM, Arnd Bergmann wrote: >>>>> On Friday 21 June 2013, Santosh Shilimkar wrote: >>>>>>> >>>>>> I was curious how you will fix that for a c file. >>>>>> Just to be clear, I was planning to do that in 3.11-rcx/3.12 >>>>>> time. Let me know if it needs to be done earlier than that. >>>>> >>>>> It breaks randconfig builds on arm-soc at the moment, so I'd >>>>> like the fix as early as possible for 3.11. >>>>> >>>> Ok, fix is at end of the email. Let me know if it makes >>>> to pass both the builds now. I have build and boot tested >>>> both ARM and THUMB2 builds on Keystone board. >>>> >>>> Regards, >>>> Santosh >>>> >>>> From 05d6a5b6cad624fb3791e8c1f8eb7c774f0790d9 Mon Sep 17 00:00:00 2001 >>>> From: Santosh Shilimkar >>>> Date: Fri, 21 Jun 2013 18:35:32 -0400 >>>> Subject: [PATCH] ARM: keystone: Move CPU bringup code to dedicated asm file >>>> >>>> Because of inline asm usage in platsmp.c, smc instruction >>>> creates build failure for ARM V6+V7 build where as using instruction >>>> encoding for smc breaks the thumb2 build. >>>> >>>> So move the code snippet to separate asm file and mark >>>> it with 'armv7-a$(plus_sec)' to avoid any build issues. >>>> >>>> Cc: Arnd Bergmann >>>> >>>> Signed-off-by: Santosh Shilimkar >>>> --- >> >> [..] >> >>>> diff --git a/arch/arm/mach-keystone/smc.S b/arch/arm/mach-keystone/smc.S >>>> new file mode 100644 >>>> index 0000000..9b9e4f7 >>>> --- /dev/null >>>> +++ b/arch/arm/mach-keystone/smc.S >>>> @@ -0,0 +1,29 @@ >>>> +/* >>>> + * Keystone Secure APIs >>>> + * >>>> + * Copyright (C) 2013 Texas Instruments, Inc. >>>> + * Santosh Shilimkar >>>> + * >>>> + * This program is free software,you can redistribute it and/or modify >>>> + * it under the terms of the GNU General Public License version 2 as >>>> + * published by the Free Software Foundation. >>>> + */ >>>> + >>>> +#include >>>> + >>>> +/** >>>> + * u32 keystone_cpu_smc(u32 command, u32 cpu, u32 addr) >>>> + * >>>> + * Low level CPU monitor API >>>> + * @command: Monitor command. >>>> + * @cpu: CPU Number >>>> + * @addr: Kernel jump address for boot CPU >>>> + * >>>> + * Return: Non zero value on failure >>>> + */ >>> >>> Oops, looks like I missed the final mail on this thread. Ignore my >>> previous mail. >>> >>> I still think it would be a good idea to try to consolidate all these >>> trivial SMC wrappers, but this remains debatable. >>> >>> >>> >>> Anyway, this looks like it should work, except: >>> >>>> +ENTRY(keystone_cpu_smc) >>>> + stmfd sp!, {r4-r12, lr} >>>> + smc #0 >>>> + dsb >>> >>> What's this DSB for? (You didn't have it in the inline asm version) >>> >> Just to drain the write buffer before resuming on non-secure side. > > Why do you need to do that? > To commit any secure side pending writes. I don't remember exactly the issues but I remember facing issues in power management sequencing with SMC calls in between. That time a dsb did the trick. In fact I use to keep 1 before SMC and 1 after. >> I actually added it while moving it to asm file. >> >>>> + ldmfd sp!, {r4-r12, pc} >>>> +ENDPROC(keystone_cpu_smc) >>> >>> r12 is caller-save btw; you don't need to preserve it. >>> >> Indeed. Will update it while adding some more SMC APIs. >> Its not harmful as such for now. > > If you could change that as soon as you make another modification to > this file, that would be appreciated. These code snippets get > cut and pasted recklessly. > Yep. Thats what I mean. Regards, Santosh