lkml.org 
[lkml]   [2019]   [Apr]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v2 1/3] ARM: use arch_extension directive instead of arch argument
On 09.04.2019 14:25, Måns Rullgård wrote:
> Stefan Agner <stefan@agner.ch> writes:
>
>> The LLVM Target parser currently does not allow to specify the security
>> extension as part of -march (see also LLVM Bug 40186 [0]). When trying
>> to use Clang with LLVM's integrated assembler, this leads to build
>> errors such as this:
>> clang-8: error: the clang compiler does not support '-Wa,-march=armv7-a+sec'
>>
>> Use ".arch_extension sec" to enable the security extension in a more
>> portable fasion. Also make sure to use ".arch armv7-a" in case a v6/v7
>> multi-platform kernel is being built.
>>
>> Note that this is technically not exactly the same as the old code
>> checked for availabilty of the security extension by calling as-instr.
>> However, there are already other sites which use ".arch_extension sec"
>> unconditionally, hence de-facto we need an assembler capable of
>> ".arch_extension sec" already today (arch/arm/mm/proc-v7.S). The
>> arch extension "sec" is available since binutils 2.21 according to
>> its documentation [1].
>>
>> [0] https://bugs.llvm.org/show_bug.cgi?id=40186
>> [1] https://sourceware.org/binutils/docs-2.21/as/ARM-Options.html
>>
>> Signed-off-by: Stefan Agner <stefan@agner.ch>
>> Acked-by: Mans Rullgard <mans@mansr.com>
>> Acked-by: Arnd Bergmann <arnd@arndb.de>
>> Acked-by: Krzysztof Kozlowski <krzk@kernel.org>
>> ---
>> Changes since v1:
>> - Explicitly specify assembler architecture as armv7-a to avoid
>> build issues when bulding v6/v7 multi arch kernel.
>>
>> arch/arm/mach-bcm/Makefile | 3 ---
>> arch/arm/mach-bcm/bcm_kona_smc.c | 2 --
>> arch/arm/mach-exynos/Makefile | 4 ----
>> arch/arm/mach-exynos/exynos-smc.S | 3 ++-
>> arch/arm/mach-exynos/sleep.S | 3 ++-
>> arch/arm/mach-highbank/Makefile | 3 ---
>> arch/arm/mach-highbank/smc.S | 3 ++-
>> arch/arm/mach-keystone/Makefile | 3 ---
>> arch/arm/mach-keystone/smc.S | 1 +
>> arch/arm/mach-omap2/Makefile | 8 --------
>> arch/arm/mach-omap2/omap-headsmp.S | 2 ++
>> arch/arm/mach-omap2/omap-smc.S | 3 ++-
>> arch/arm/mach-omap2/sleep33xx.S | 1 +
>> arch/arm/mach-omap2/sleep34xx.S | 2 ++
>> arch/arm/mach-omap2/sleep43xx.S | 2 ++
>> arch/arm/mach-omap2/sleep44xx.S | 2 ++
>> arch/arm/mach-tango/Makefile | 3 ---
>> arch/arm/mach-tango/smc.S | 1 +
>> 18 files changed, 19 insertions(+), 30 deletions(-)
>
> [...]
>
>> diff --git a/arch/arm/mach-bcm/bcm_kona_smc.c b/arch/arm/mach-bcm/bcm_kona_smc.c
>> index a55a7ecf146a..541e850a736c 100644
>> --- a/arch/arm/mach-bcm/bcm_kona_smc.c
>> +++ b/arch/arm/mach-bcm/bcm_kona_smc.c
>> @@ -125,9 +125,7 @@ static int bcm_kona_do_smc(u32 service_id, u32 buffer_phys)
>> __asmeq("%2", "r4")
>> __asmeq("%3", "r5")
>> __asmeq("%4", "r6")
>> -#ifdef REQUIRES_SEC
>> ".arch_extension sec\n"
>> -#endif
>> " smc #0\n"
>> : "=r" (ip), "=r" (r0)
>> : "r" (r4), "r" (r5), "r" (r6)
>
> [...]
>
>> diff --git a/arch/arm/mach-keystone/smc.S b/arch/arm/mach-keystone/smc.S
>> index d15de8179fab..ec03dc499270 100644
>> --- a/arch/arm/mach-keystone/smc.S
>> +++ b/arch/arm/mach-keystone/smc.S
>> @@ -21,6 +21,7 @@
>> *
>> * Return: Non zero value on failure
>> */
>> + .arch_extension sec
>> ENTRY(keystone_cpu_smc)
>> stmfd sp!, {r4-r11, lr}
>> smc #0
>
> [...]
>
>> diff --git a/arch/arm/mach-tango/smc.S b/arch/arm/mach-tango/smc.S
>> index 361a8dc89804..cf2d21e5226c 100644
>> --- a/arch/arm/mach-tango/smc.S
>> +++ b/arch/arm/mach-tango/smc.S
>> @@ -1,6 +1,7 @@
>> /* SPDX-License-Identifier: GPL-2.0 */
>> #include <linux/linkage.h>
>>
>> + .arch_extension sec
>> ENTRY(tango_smc)
>> push {lr}
>> mov ip, r1

Actually, mach-tango uses dsb and needs the .arch directive. Will fix in
v3.

--
Stefan

>
> Is there some reason these three don't need the .arch directive?

\
 
 \ /
  Last update: 2019-04-10 10:21    [W:0.112 / U:0.604 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site