Messages in this thread | | | Date | Mon, 08 Apr 2019 22:23:19 +0200 | From | Stefan Agner <> | Subject | Re: [PATCH 1/3] ARM: use arch_extension directive instead of arch argument |
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On 31.03.2019 19:34, Arnd Bergmann wrote: > On Sun, Mar 24, 2019 at 3:06 AM Arnd Bergmann <arnd@arndb.de> wrote: >> >> On Sat, Mar 23, 2019 at 4:52 PM Stefan Agner <stefan@agner.ch> wrote: >> > >> > 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 a 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. >> > >> > 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> >> >> This sounds like a good idea. I think we have platform specific >> minimum toolchain versions elsewhere, but I don't see a problem >> with raising the minimum version for all the armv7ve platforms. >> >> I've added this patch to my randconfig test queue, but please >> send it to arm@kernel.org for inclusion when you have >> collected more Acks. >> >> Do you have a git tree with other patches required for the >> integrated assembler? I might try that out as well with >> my randconfig tree. At the moment I'm building with >> clang-8 and a small number of patches on top. >> >> Acked-by: Arnd Bergmann <arnd@arndb.de> > > I only now looked at the results and found a problem: > In a mixed v6/v7 configuration, the arch_extension flag > is not sufficient, and for armv6+sec, we get failures like > > /git/arm-soc/arch/arm/mach-omap2/sleep44xx.S: Assembler messages: > /git/arm-soc/arch/arm/mach-omap2/sleep44xx.S:343: Error: selected > processor does not support `isb' in ARM mode > /git/arm-soc/arch/arm/mach-omap2/sleep44xx.S:350: Error: selected > processor does not support `dsb' in ARM mode > /git/arm-soc/arch/arm/mach-omap2/sleep44xx.S:351: Error: selected > processor does not support `dmb' in ARM mode > clang: error: assembler command failed with exit code 1 (use -v to see > invocation) > /git/arm-soc/scripts/Makefile.build:369: recipe for target > 'arch/arm/mach-omap2/sleep44xx.o' failed > make[3]: *** [arch/arm/mach-omap2/sleep44xx.o] Error 1 > > ==> build/arm/0x64728DCE_defconfig/log <== > /git/arm-soc/arch/arm/mach-omap2/omap-smc.S: Assembler messages: > /git/arm-soc/arch/arm/mach-omap2/omap-smc.S:31: Error: selected > processor does not support `dsb' in ARM mode > /git/arm-soc/arch/arm/mach-omap2/omap-smc.S:53: Error: selected > processor does not support `dsb' in ARM mode > /git/arm-soc/arch/arm/mach-omap2/omap-smc.S:54: Error: selected > processor does not support `dmb' in ARM mode
Hm, I guess I can just use .arch armv7-a in those cases, as we use in other places.
Thanks for testing! Will send a v2.
-- Stefan
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