From: Dave Martin <Dave.Martin@arm.com> To: Suzuki K Poulose <Suzuki.Poulose@arm.com> Cc: "Catalin Marinas" <catalin.marinas@arm.com>, linux-arch@vger.kernel.org, libc-alpha@sourceware.org, "Ard Biesheuvel" <ard.biesheuvel@linaro.org>, "Szabolcs Nagy" <szabolcs.nagy@arm.com>, "Richard Sandiford" <richard.sandiford@arm.com>, "Will Deacon" <will.deacon@arm.com>, "Alex Bennée" <alex.bennee@linaro.org>, kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH v2 10/28] arm64/sve: Low-level CPU setup Date: Thu, 5 Oct 2017 12:22:18 +0100 [thread overview] Message-ID: <20171005112217.GW3611@e103592.cambridge.arm.com> (raw) In-Reply-To: <76020d51-a971-e73e-9fba-1e2ec97985dc@arm.com> On Thu, Oct 05, 2017 at 12:04:12PM +0100, Suzuki K Poulose wrote: > On 05/10/17 11:47, Dave Martin wrote: [...] > >>>On Thu, Aug 31, 2017 at 06:00:42PM +0100, Dave P Martin wrote: > >>>>diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S > >>>>index 877d42f..dd22ef2 100644 > >>>>--- a/arch/arm64/mm/proc.S > >>>>+++ b/arch/arm64/mm/proc.S > >>>>@@ -27,6 +27,7 @@ > >>>> #include <asm/pgtable-hwdef.h> > >>>> #include <asm/cpufeature.h> > >>>> #include <asm/alternative.h> > >>>>+#include <asm/sysreg.h> > >>>> #ifdef CONFIG_ARM64_64K_PAGES > >>>> #define TCR_TG_FLAGS TCR_TG0_64K | TCR_TG1_64K > >>>>@@ -186,8 +187,17 @@ ENTRY(__cpu_setup) > >>>> tlbi vmalle1 // Invalidate local TLB > >>>> dsb nsh > >>>>- mov x0, #3 << 20 > >>>>- msr cpacr_el1, x0 // Enable FP/ASIMD > >>>>+ mov x0, #3 << 20 // FEN > >>>>+ > >>>>+ /* SVE */ > >>>>+ mrs x5, id_aa64pfr0_el1 > >>>>+ ubfx x5, x5, #ID_AA64PFR0_SVE_SHIFT, #4 > >>>>+ cbz x5, 1f > >>>>+ > >>>>+ bic x0, x0, #CPACR_EL1_ZEN > >>>>+ orr x0, x0, #CPACR_EL1_ZEN_EL1EN // SVE: trap for EL0, not EL1 > >>>>+1: msr cpacr_el1, x0 // Enable FP/ASIMD [..] > >I can add a helper el1_enable_sve() say, and call it before probing > >ZCR_EL1 in the cpufeatures code. > > > >This makes enabling SVE a side-effect of the cpufeatures code, which > >I'm not that comfortable with -- it feels like something that later > >refactoring could easily break. > > > >I can also add an explicit call to el1_enable_sve() in sve_setup(), > >but this only works on the boot cpu. > > > >For secondaries, I could add something in secondary_start_kernel(), > >but this looks incongruous since there's no other call to do something > >similar yet. > > > > > >** Suzuki, do we have any other case where the trap for a CPU feature is > >turned off by the cpufeatures code? If there's already a template for > >this then I'm happy to follow it. > > The closest thing you have is an "enable" callback for each "available" > capability, which gets invoked on all CPUs (boot time active CPUs and the > ones which are brought up later). This is used by things like, PAN to > do some CPU specific setups. > > See : > enable_cpu_capabilities() // For all boot time active CPUs > and > verify_local_cpu_features() // For CPUs brought up later That may allow me to do something tidier, provided the enable method is called early enough. I'll take a look. Cheers ---Dave
WARNING: multiple messages have this Message-ID (diff)
From: Dave.Martin@arm.com (Dave Martin) To: linux-arm-kernel@lists.infradead.org Subject: [PATCH v2 10/28] arm64/sve: Low-level CPU setup Date: Thu, 5 Oct 2017 12:22:18 +0100 [thread overview] Message-ID: <20171005112217.GW3611@e103592.cambridge.arm.com> (raw) In-Reply-To: <76020d51-a971-e73e-9fba-1e2ec97985dc@arm.com> On Thu, Oct 05, 2017 at 12:04:12PM +0100, Suzuki K Poulose wrote: > On 05/10/17 11:47, Dave Martin wrote: [...] > >>>On Thu, Aug 31, 2017 at 06:00:42PM +0100, Dave P Martin wrote: > >>>>diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S > >>>>index 877d42f..dd22ef2 100644 > >>>>--- a/arch/arm64/mm/proc.S > >>>>+++ b/arch/arm64/mm/proc.S > >>>>@@ -27,6 +27,7 @@ > >>>> #include <asm/pgtable-hwdef.h> > >>>> #include <asm/cpufeature.h> > >>>> #include <asm/alternative.h> > >>>>+#include <asm/sysreg.h> > >>>> #ifdef CONFIG_ARM64_64K_PAGES > >>>> #define TCR_TG_FLAGS TCR_TG0_64K | TCR_TG1_64K > >>>>@@ -186,8 +187,17 @@ ENTRY(__cpu_setup) > >>>> tlbi vmalle1 // Invalidate local TLB > >>>> dsb nsh > >>>>- mov x0, #3 << 20 > >>>>- msr cpacr_el1, x0 // Enable FP/ASIMD > >>>>+ mov x0, #3 << 20 // FEN > >>>>+ > >>>>+ /* SVE */ > >>>>+ mrs x5, id_aa64pfr0_el1 > >>>>+ ubfx x5, x5, #ID_AA64PFR0_SVE_SHIFT, #4 > >>>>+ cbz x5, 1f > >>>>+ > >>>>+ bic x0, x0, #CPACR_EL1_ZEN > >>>>+ orr x0, x0, #CPACR_EL1_ZEN_EL1EN // SVE: trap for EL0, not EL1 > >>>>+1: msr cpacr_el1, x0 // Enable FP/ASIMD [..] > >I can add a helper el1_enable_sve() say, and call it before probing > >ZCR_EL1 in the cpufeatures code. > > > >This makes enabling SVE a side-effect of the cpufeatures code, which > >I'm not that comfortable with -- it feels like something that later > >refactoring could easily break. > > > >I can also add an explicit call to el1_enable_sve() in sve_setup(), > >but this only works on the boot cpu. > > > >For secondaries, I could add something in secondary_start_kernel(), > >but this looks incongruous since there's no other call to do something > >similar yet. > > > > > >** Suzuki, do we have any other case where the trap for a CPU feature is > >turned off by the cpufeatures code? If there's already a template for > >this then I'm happy to follow it. > > The closest thing you have is an "enable" callback for each "available" > capability, which gets invoked on all CPUs (boot time active CPUs and the > ones which are brought up later). This is used by things like, PAN to > do some CPU specific setups. > > See : > enable_cpu_capabilities() // For all boot time active CPUs > and > verify_local_cpu_features() // For CPUs brought up later That may allow me to do something tidier, provided the enable method is called early enough. I'll take a look. Cheers ---Dave
next prev parent reply other threads:[~2017-10-05 11:22 UTC|newest] Thread overview: 224+ messages / expand[flat|nested] mbox.gz Atom feed top 2017-08-31 17:00 [PATCH v2 00/28] ARM Scalable Vector Extension (SVE) Dave Martin 2017-08-31 17:00 ` Dave Martin 2017-08-31 17:00 ` [PATCH v2 01/28] regset: Add support for dynamically sized regsets Dave Martin 2017-08-31 17:00 ` Dave Martin 2017-08-31 17:00 ` [PATCH v2 02/28] arm64: KVM: Hide unsupported AArch64 CPU features from guests Dave Martin 2017-08-31 17:00 ` Dave Martin 2017-09-13 14:37 ` Alex Bennée 2017-09-13 14:37 ` Alex Bennée 2017-09-13 14:37 ` Alex Bennée 2017-09-15 0:04 ` Dave Martin 2017-09-15 0:04 ` Dave Martin 2017-08-31 17:00 ` [PATCH v2 03/28] arm64: efi: Add missing Kconfig dependency on KERNEL_MODE_NEON Dave Martin 2017-08-31 17:00 ` Dave Martin 2017-08-31 17:00 ` [PATCH v2 04/28] arm64: Port deprecated instruction emulation to new sysctl interface Dave Martin 2017-08-31 17:00 ` Dave Martin 2017-08-31 17:00 ` [PATCH v2 05/28] arm64: fpsimd: Simplify uses of {set,clear}_ti_thread_flag() Dave Martin 2017-08-31 17:00 ` [PATCH v2 05/28] arm64: fpsimd: Simplify uses of {set, clear}_ti_thread_flag() Dave Martin 2017-08-31 17:00 ` [PATCH v2 06/28] arm64/sve: System register and exception syndrome definitions Dave Martin 2017-08-31 17:00 ` Dave Martin 2017-09-13 14:48 ` Alex Bennée 2017-09-13 14:48 ` Alex Bennée 2017-09-13 14:48 ` Alex Bennée 2017-08-31 17:00 ` [PATCH v2 07/28] arm64/sve: Low-level SVE architectural state manipulation functions Dave Martin 2017-08-31 17:00 ` Dave Martin 2017-09-13 15:39 ` Alex Bennée 2017-09-13 15:39 ` Alex Bennée 2017-09-13 15:39 ` Alex Bennée 2017-08-31 17:00 ` [PATCH v2 08/28] arm64/sve: Kconfig update and conditional compilation support Dave Martin 2017-08-31 17:00 ` Dave Martin 2017-08-31 17:00 ` [PATCH v2 09/28] arm64/sve: Signal frame and context structure definition Dave Martin 2017-08-31 17:00 ` Dave Martin 2017-09-13 13:36 ` Catalin Marinas 2017-09-13 13:36 ` Catalin Marinas 2017-09-13 21:33 ` Dave Martin 2017-09-13 21:33 ` Dave Martin 2017-08-31 17:00 ` [PATCH v2 10/28] arm64/sve: Low-level CPU setup Dave Martin 2017-08-31 17:00 ` Dave Martin 2017-09-13 13:32 ` Catalin Marinas 2017-09-13 13:32 ` Catalin Marinas 2017-09-13 19:21 ` Dave Martin 2017-09-13 19:21 ` Dave Martin 2017-09-13 19:21 ` Dave Martin 2017-10-05 10:47 ` Dave Martin 2017-10-05 10:47 ` Dave Martin 2017-10-05 11:04 ` Suzuki K Poulose 2017-10-05 11:04 ` Suzuki K Poulose 2017-10-05 11:22 ` Dave Martin [this message] 2017-10-05 11:22 ` Dave Martin 2017-08-31 17:00 ` [PATCH v2 11/28] arm64/sve: Core task context handling Dave Martin 2017-08-31 17:00 ` Dave Martin 2017-09-13 14:33 ` Catalin Marinas 2017-09-13 14:33 ` Catalin Marinas 2017-09-14 19:55 ` Dave Martin 2017-09-14 19:55 ` Dave Martin 2017-09-20 13:58 ` Catalin Marinas 2017-09-20 13:58 ` Catalin Marinas 2017-10-03 11:11 ` Dave Martin 2017-10-03 11:11 ` Dave Martin 2017-10-04 17:29 ` Catalin Marinas 2017-10-04 17:29 ` Catalin Marinas 2017-10-03 11:33 ` Dave Martin 2017-10-03 11:33 ` Dave Martin 2017-10-05 11:28 ` Catalin Marinas 2017-10-05 11:28 ` Catalin Marinas 2017-10-06 13:10 ` Dave Martin 2017-10-06 13:10 ` Dave Martin 2017-10-06 13:36 ` Catalin Marinas 2017-10-06 13:36 ` Catalin Marinas 2017-10-06 15:15 ` Dave Martin 2017-10-06 15:15 ` Dave Martin 2017-10-06 15:33 ` Catalin Marinas 2017-10-06 15:33 ` Catalin Marinas 2017-09-13 17:26 ` Catalin Marinas 2017-09-13 17:26 ` Catalin Marinas 2017-09-13 19:17 ` Dave Martin 2017-09-13 19:17 ` Dave Martin 2017-09-13 22:21 ` Catalin Marinas 2017-09-13 22:21 ` Catalin Marinas 2017-09-14 19:40 ` Dave Martin 2017-09-14 19:40 ` Dave Martin 2017-09-19 17:13 ` Catalin Marinas 2017-09-19 17:13 ` Catalin Marinas 2017-08-31 17:00 ` [PATCH v2 12/28] arm64/sve: Support vector length resetting for new processes Dave Martin 2017-08-31 17:00 ` Dave Martin 2017-09-14 8:47 ` Alex Bennée 2017-09-14 8:47 ` Alex Bennée 2017-09-14 8:47 ` Alex Bennée 2017-08-31 17:00 ` [PATCH v2 13/28] arm64/sve: Signal handling support Dave Martin 2017-08-31 17:00 ` Dave Martin 2017-09-14 9:30 ` Alex Bennée 2017-09-14 9:30 ` Alex Bennée 2017-09-14 9:30 ` Alex Bennée 2017-08-31 17:00 ` [PATCH v2 14/28] arm64/sve: Backend logic for setting the vector length Dave Martin 2017-08-31 17:00 ` Dave Martin 2017-09-13 17:29 ` Catalin Marinas 2017-09-13 17:29 ` Catalin Marinas 2017-09-13 19:06 ` Dave Martin 2017-09-13 19:06 ` Dave Martin 2017-09-13 22:11 ` Catalin Marinas 2017-09-13 22:11 ` Catalin Marinas 2017-10-05 16:42 ` Dave Martin 2017-10-05 16:42 ` Dave Martin 2017-10-05 16:53 ` Catalin Marinas 2017-10-05 16:53 ` Catalin Marinas 2017-10-05 17:04 ` Dave Martin 2017-10-05 17:04 ` Dave Martin 2017-09-20 10:57 ` Alan Hayward 2017-09-20 10:57 ` Alan Hayward 2017-09-20 10:59 ` Alan Hayward 2017-09-20 10:59 ` Alan Hayward 2017-09-20 11:09 ` Dave Martin 2017-09-20 11:09 ` Dave Martin 2017-09-20 18:08 ` Alan Hayward 2017-09-20 18:08 ` Alan Hayward 2017-09-21 11:19 ` Dave Martin 2017-09-21 11:19 ` Dave Martin 2017-09-21 11:57 ` Alan Hayward 2017-09-21 11:57 ` Alan Hayward 2017-08-31 17:00 ` [PATCH v2 15/28] arm64: cpufeature: Move sys_caps_initialised declarations Dave Martin 2017-08-31 17:00 ` Dave Martin 2017-09-14 9:33 ` Alex Bennée 2017-09-14 9:33 ` Alex Bennée 2017-09-14 9:33 ` Alex Bennée 2017-09-14 9:35 ` Suzuki K Poulose 2017-09-14 9:35 ` Suzuki K Poulose 2017-08-31 17:00 ` [PATCH v2 16/28] arm64/sve: Probe SVE capabilities and usable vector lengths Dave Martin 2017-08-31 17:00 ` Dave Martin 2017-09-14 9:45 ` Alex Bennée 2017-09-14 9:45 ` Alex Bennée 2017-09-14 9:45 ` Alex Bennée 2017-09-28 14:22 ` Dave Martin 2017-09-28 14:22 ` Dave Martin 2017-09-28 17:32 ` Alex Bennée 2017-09-28 17:32 ` Alex Bennée 2017-09-28 17:32 ` Alex Bennée 2017-08-31 17:00 ` [PATCH v2 17/28] arm64/sve: Preserve SVE registers around kernel-mode NEON use Dave Martin 2017-08-31 17:00 ` Dave Martin 2017-09-14 10:52 ` Alex Bennée 2017-09-14 10:52 ` Alex Bennée 2017-09-14 10:52 ` Alex Bennée 2017-08-31 17:00 ` [PATCH v2 18/28] arm64/sve: Preserve SVE registers around EFI runtime service calls Dave Martin 2017-08-31 17:00 ` Dave Martin 2017-08-31 17:00 ` Dave Martin 2017-09-14 11:01 ` Alex Bennée 2017-09-14 11:01 ` Alex Bennée 2017-09-14 11:01 ` Alex Bennée 2017-08-31 17:00 ` [PATCH v2 19/28] arm64/sve: ptrace and ELF coredump support Dave Martin 2017-08-31 17:00 ` Dave Martin 2017-09-06 16:21 ` Okamoto, Takayuki 2017-09-06 16:21 ` Okamoto, Takayuki 2017-09-06 18:16 ` Dave Martin 2017-09-06 18:16 ` Dave Martin 2017-09-07 5:11 ` Okamoto, Takayuki 2017-09-07 5:11 ` Okamoto, Takayuki 2017-09-07 5:11 ` Okamoto, Takayuki 2017-09-08 13:11 ` Dave Martin 2017-09-08 13:11 ` Dave Martin 2017-09-14 12:57 ` Alex Bennée 2017-09-14 12:57 ` Alex Bennée 2017-09-14 12:57 ` Alex Bennée 2017-09-28 14:57 ` Dave Martin 2017-09-28 14:57 ` Dave Martin 2017-09-29 12:46 ` Dave Martin 2017-09-29 12:46 ` Dave Martin 2017-08-31 17:00 ` [PATCH v2 20/28] arm64/sve: Add prctl controls for userspace vector length management Dave Martin 2017-08-31 17:00 ` Dave Martin 2017-09-14 13:02 ` Alex Bennée 2017-09-14 13:02 ` Alex Bennée 2017-09-14 13:02 ` Alex Bennée 2017-08-31 17:00 ` [PATCH v2 21/28] arm64/sve: Add sysctl to set the default vector length for new processes Dave Martin 2017-08-31 17:00 ` Dave Martin 2017-09-14 13:05 ` Alex Bennée 2017-09-14 13:05 ` Alex Bennée 2017-09-14 13:05 ` Alex Bennée 2017-08-31 17:00 ` [PATCH v2 22/28] arm64/sve: KVM: Prevent guests from using SVE Dave Martin 2017-08-31 17:00 ` Dave Martin 2017-09-14 13:28 ` Alex Bennée 2017-09-14 13:28 ` Alex Bennée 2017-09-14 13:28 ` Alex Bennée 2017-08-31 17:00 ` [PATCH v2 23/28] arm64/sve: KVM: Treat guest SVE use as undefined instruction execution Dave Martin 2017-08-31 17:00 ` Dave Martin 2017-09-14 13:30 ` Alex Bennée 2017-09-14 13:30 ` Alex Bennée 2017-09-14 13:30 ` Alex Bennée 2017-09-14 13:31 ` Alex Bennée 2017-09-14 13:31 ` Alex Bennée 2017-09-14 13:31 ` Alex Bennée 2017-09-29 13:00 ` Dave Martin 2017-09-29 13:00 ` Dave Martin 2017-09-29 14:43 ` Alex Bennée 2017-09-29 14:43 ` Alex Bennée 2017-09-29 14:43 ` Alex Bennée 2017-08-31 17:00 ` [PATCH v2 24/28] arm64/sve: KVM: Hide SVE from CPU features exposed to guests Dave Martin 2017-08-31 17:00 ` Dave Martin 2017-09-14 13:32 ` Alex Bennée 2017-09-14 13:32 ` Alex Bennée 2017-09-14 13:32 ` Alex Bennée 2017-08-31 17:00 ` [PATCH v2 25/28] arm64/sve: Detect SVE and activate runtime support Dave Martin 2017-08-31 17:00 ` Dave Martin 2017-08-31 17:00 ` [PATCH v2 26/28] arm64/sve: Add documentation Dave Martin 2017-08-31 17:00 ` Dave Martin 2017-10-05 16:39 ` Szabolcs Nagy 2017-10-05 16:39 ` Szabolcs Nagy 2017-10-05 17:02 ` Dave Martin 2017-10-05 17:02 ` Dave Martin 2017-10-06 15:43 ` Szabolcs Nagy 2017-10-06 15:43 ` Szabolcs Nagy 2017-10-06 17:37 ` Dave Martin 2017-10-06 17:37 ` Dave Martin 2017-10-09 9:34 ` Alex Bennée 2017-10-09 9:34 ` Alex Bennée 2017-10-09 9:34 ` Alex Bennée 2017-10-09 9:49 ` Dave Martin 2017-10-09 9:49 ` Dave Martin 2017-10-09 14:07 ` Alex Bennée 2017-10-09 14:07 ` Alex Bennée 2017-10-09 14:07 ` Alex Bennée 2017-10-09 16:20 ` Dave Martin 2017-10-09 16:20 ` Dave Martin 2017-08-31 17:00 ` [RFC PATCH v2 27/28] arm64: signal: Report signal frame size to userspace via auxv Dave Martin 2017-08-31 17:00 ` Dave Martin 2017-08-31 17:00 ` Dave Martin 2017-08-31 17:01 ` [RFC PATCH v2 28/28] arm64/sve: signal: Include SVE when computing AT_MINSIGSTKSZ Dave Martin 2017-08-31 17:01 ` Dave Martin
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