On 09.04.2019 14:25, Måns Rullgård wrote: > Stefan Agner <ste...@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 <ste...@agner.ch> >> Acked-by: Mans Rullgard <m...@mansr.com> >> Acked-by: Arnd Bergmann <a...@arndb.de> >> Acked-by: Krzysztof Kozlowski <k...@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?