Messages in this thread | | | From | Arnd Bergmann <> | Date | Mon, 1 Apr 2019 00:34:49 +0700 | Subject | Re: [PATCH 1/3] ARM: use arch_extension directive instead of arch argument |
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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
Arnd
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