[PATCH] arm64: Expose SVE2 features for userspace

[PATCH] arm64: Expose SVE2 features for userspace

[Dave Martin]

This patch provides support for reporting the presence of SVE2 and
its optional features to userspace.

This will also enable visibility of SVE2 for guests, when KVM
support for SVE-enabled guests is available.

Signed-off-by: Dave Martin <Dave.Martin@arm.com>
---

This patch is based on

git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git
f645d37e281f ("Merge remote-tracking branch 'arm64/for-next/mmiowb' into for-next/core")

(for Andrew Murray's HWCAP2 support).


Tested with the Arm Fast Model SVE2 plugin.

For KVM, tested with:

git://linux-arm.org/linux-dm.git sve-kvm-fixes/v2/head
http://linux-arm.org/git?p=linux-dm.git;a=shortlog;h=refs/heads/sve-kvm-fixes/v2/head

(which is also now merged to kvmarm/next).

 Documentation/arm64/cpu-feature-registers.txt | 16 ++++++++++++++++
 Documentation/arm64/elf_hwcaps.txt            | 24 ++++++++++++++++++++++++
 Documentation/arm64/sve.txt                   | 17 +++++++++++++++++
 arch/arm64/Kconfig                            |  3 +++
 arch/arm64/include/asm/hwcap.h                |  6 ++++++
 arch/arm64/include/asm/sysreg.h               | 14 ++++++++++++++
 arch/arm64/include/uapi/asm/hwcap.h           |  6 ++++++
 arch/arm64/kernel/cpufeature.c                | 17 ++++++++++++++++-
 arch/arm64/kernel/cpuinfo.c                   |  6 ++++++
 9 files changed, 108 insertions(+), 1 deletion(-)

diff --git a/Documentation/arm64/cpu-feature-registers.txt b/Documentation/arm64/cpu-feature-registers.txt
index d4b4dd1f..4e47a01 100644
--- a/Documentation/arm64/cpu-feature-registers.txt
+++ b/Documentation/arm64/cpu-feature-registers.txt
@@ -209,6 +209,22 @@ infrastructure:
      | AT                           | [35-32] |    y    |
      x--------------------------------------------------x
 
+  6) ID_AA64ZFR0_EL1 - SVE feature ID register 0
+
+     x--------------------------------------------------x
+     | Name                         |  bits   | visible |
+     |--------------------------------------------------|
+     | SM4                          | [43-40] |    y    |
+     x--------------------------------------------------x
+     | SHA3                         | [35-32] |    y    |
+     x--------------------------------------------------x
+     | BitPerm                      | [19-16] |    y    |
+     x--------------------------------------------------x
+     | AES                          | [7-4]   |    y    |
+     x--------------------------------------------------x
+     | SVEVer                       | [3-0]   |    y    |
+     x--------------------------------------------------x
+
 Appendix I: Example
 ---------------------------
 
diff --git a/Documentation/arm64/elf_hwcaps.txt b/Documentation/arm64/elf_hwcaps.txt
index 55431fd..b73a251 100644
--- a/Documentation/arm64/elf_hwcaps.txt
+++ b/Documentation/arm64/elf_hwcaps.txt
@@ -163,6 +163,30 @@ HWCAP_SVE
 
     Functionality implied by ID_AA64PFR0_EL1.SVE == 0b0001.
 
+HWCAP2_SVE2
+
+    Functionality implied by ID_AA64ZFR0_EL1.SVEVer == 0b0001.
+
+HWCAP2_SVEAES
+
+    Functionality implied by ID_AA64ZFR0_EL1.AES == 0b0001.
+
+HWCAP2_SVEPMULL
+
+    Functionality implied by ID_AA64ZFR0_EL1.AES == 0b0010.
+
+HWCAP2_SVEBITPERM
+
+    Functionality implied by ID_AA64ZFR0_EL1.BitPerm == 0b0001.
+
+HWCAP2_SVESHA3
+
+    Functionality implied by ID_AA64ZFR0_EL1.SHA3 == 0b0001.
+
+HWCAP2_SVESM4
+
+    Functionality implied by ID_AA64ZFR0_EL1.SM4 == 0b0001.
+
 HWCAP_ASIMDFHM
 
    Functionality implied by ID_AA64ISAR0_EL1.FHM == 0b0001.
diff --git a/Documentation/arm64/sve.txt b/Documentation/arm64/sve.txt
index 7169a0e..9940e92 100644
--- a/Documentation/arm64/sve.txt
+++ b/Documentation/arm64/sve.txt
@@ -34,6 +34,23 @@ model features for SVE is included in Appendix A.
   following sections: software that needs to verify that those interfaces are
   present must check for HWCAP_SVE instead.
 
+* On hardware that supports the SVE2 extensions, HWCAP2_SVE2 will also
+  be reported in the AT_HWCAP2 aux vector entry.  In addition to this,
+  optional extensions to SVE2 may be reported by the presence of:
+
+	HWCAP2_SVE2
+	HWCAP2_SVEAES
+	HWCAP2_SVEPMULL
+	HWCAP2_SVEBITPERM
+	HWCAP2_SVESHA3
+	HWCAP2_SVESM4
+
+  This list may be extended over time as the SVE architecture evolves.
+
+  These extensions are also reported via the CPU ID register ID_AA64ZFR0_EL1,
+  which userspace can read using an MRS instruction.  See elf_hwcaps.txt and
+  cpu-feature-registers.txt for details.
+
 * Debuggers should restrict themselves to interacting with the target via the
   NT_ARM_SVE regset.  The recommended way of detecting support for this regset
   is to connect to a target process first and then attempt a
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index c383625..4d79446 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -1322,6 +1322,9 @@ config ARM64_SVE
 
 	  To enable use of this extension on CPUs that implement it, say Y.
 
+	  On CPUs that support the SVE2 extensions, this option will enable
+	  those too.
+
 	  Note that for architectural reasons, firmware _must_ implement SVE
 	  support when running on SVE capable hardware.  The required support
 	  is present in:
diff --git a/arch/arm64/include/asm/hwcap.h b/arch/arm64/include/asm/hwcap.h
index f78c86c..b4bfb66 100644
--- a/arch/arm64/include/asm/hwcap.h
+++ b/arch/arm64/include/asm/hwcap.h
@@ -89,6 +89,12 @@
 
 #define __khwcap2_feature(x)		(const_ilog2(HWCAP2_ ## x) + 32)
 #define KERNEL_HWCAP_DCPODP		__khwcap2_feature(DCPODP)
+#define KERNEL_HWCAP_SVE2		__khwcap2_feature(SVE2)
+#define KERNEL_HWCAP_SVEAES		__khwcap2_feature(SVEAES)
+#define KERNEL_HWCAP_SVEPMULL		__khwcap2_feature(SVEPMULL)
+#define KERNEL_HWCAP_SVEBITPERM		__khwcap2_feature(SVEBITPERM)
+#define KERNEL_HWCAP_SVESHA3		__khwcap2_feature(SVESHA3)
+#define KERNEL_HWCAP_SVESM4		__khwcap2_feature(SVESM4)
 
 /*
  * This yields a mask that user programs can use to figure out what
diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h
index 5b267de..29c6559 100644
--- a/arch/arm64/include/asm/sysreg.h
+++ b/arch/arm64/include/asm/sysreg.h
@@ -606,6 +606,20 @@
 #define ID_AA64PFR1_SSBS_PSTATE_ONLY	1
 #define ID_AA64PFR1_SSBS_PSTATE_INSNS	2
 
+/* id_aa64zfr0 */
+#define ID_AA64ZFR0_SM4_SHIFT		40
+#define ID_AA64ZFR0_SHA3_SHIFT		32
+#define ID_AA64ZFR0_BITPERM_SHIFT	16
+#define ID_AA64ZFR0_AES_SHIFT		4
+#define ID_AA64ZFR0_SVEVER_SHIFT	0
+
+#define ID_AA64ZFR0_SM4			0x1
+#define ID_AA64ZFR0_SHA3		0x1
+#define ID_AA64ZFR0_BITPERM		0x1
+#define ID_AA64ZFR0_AES			0x1
+#define ID_AA64ZFR0_AES_PMULL		0x2
+#define ID_AA64ZFR0_SVEVER_SVE2		0x1
+
 /* id_aa64mmfr0 */
 #define ID_AA64MMFR0_TGRAN4_SHIFT	28
 #define ID_AA64MMFR0_TGRAN64_SHIFT	24
diff --git a/arch/arm64/include/uapi/asm/hwcap.h b/arch/arm64/include/uapi/asm/hwcap.h
index d64af39..1a772b1 100644
--- a/arch/arm64/include/uapi/asm/hwcap.h
+++ b/arch/arm64/include/uapi/asm/hwcap.h
@@ -57,5 +57,11 @@
  * HWCAP2 flags - for AT_HWCAP2
  */
 #define HWCAP2_DCPODP		(1 << 0)
+#define HWCAP2_SVE2		(1 << 1)
+#define HWCAP2_SVEAES		(1 << 2)
+#define HWCAP2_SVEPMULL		(1 << 3)
+#define HWCAP2_SVEBITPERM	(1 << 4)
+#define HWCAP2_SVESHA3		(1 << 5)
+#define HWCAP2_SVESM4		(1 << 6)
 
 #endif /* _UAPI__ASM_HWCAP_H */
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 9d18e45..d856c55 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -184,6 +184,15 @@ static const struct arm64_ftr_bits ftr_id_aa64pfr1[] = {
 	ARM64_FTR_END,
 };
 
+static const struct arm64_ftr_bits ftr_id_aa64zfr0[] = {
+	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ZFR0_SM4_SHIFT, 4, 0),
+	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ZFR0_SHA3_SHIFT, 4, 0),
+	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ZFR0_BITPERM_SHIFT, 4, 0),
+	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ZFR0_AES_SHIFT, 4, 0),
+	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ZFR0_SVEVER_SHIFT, 4, 0),
+	ARM64_FTR_END,
+};
+
 static const struct arm64_ftr_bits ftr_id_aa64mmfr0[] = {
 	S_ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR0_TGRAN4_SHIFT, 4, ID_AA64MMFR0_TGRAN4_NI),
 	S_ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR0_TGRAN64_SHIFT, 4, ID_AA64MMFR0_TGRAN64_NI),
@@ -392,7 +401,7 @@ static const struct __ftr_reg_entry {
 	/* Op1 = 0, CRn = 0, CRm = 4 */
 	ARM64_FTR_REG(SYS_ID_AA64PFR0_EL1, ftr_id_aa64pfr0),
 	ARM64_FTR_REG(SYS_ID_AA64PFR1_EL1, ftr_id_aa64pfr1),
-	ARM64_FTR_REG(SYS_ID_AA64ZFR0_EL1, ftr_raz),
+	ARM64_FTR_REG(SYS_ID_AA64ZFR0_EL1, ftr_id_aa64zfr0),
 
 	/* Op1 = 0, CRn = 0, CRm = 5 */
 	ARM64_FTR_REG(SYS_ID_AA64DFR0_EL1, ftr_id_aa64dfr0),
@@ -1610,6 +1619,12 @@ static const struct arm64_cpu_capabilities arm64_elf_hwcaps[] = {
 	HWCAP_CAP(SYS_ID_AA64MMFR2_EL1, ID_AA64MMFR2_AT_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, KERNEL_HWCAP_USCAT),
 #ifdef CONFIG_ARM64_SVE
 	HWCAP_CAP(SYS_ID_AA64PFR0_EL1, ID_AA64PFR0_SVE_SHIFT, FTR_UNSIGNED, ID_AA64PFR0_SVE, CAP_HWCAP, KERNEL_HWCAP_SVE),
+	HWCAP_CAP(SYS_ID_AA64ZFR0_EL1, ID_AA64ZFR0_SVEVER_SHIFT, FTR_UNSIGNED, ID_AA64ZFR0_SVEVER_SVE2, CAP_HWCAP, KERNEL_HWCAP_SVE2),
+	HWCAP_CAP(SYS_ID_AA64ZFR0_EL1, ID_AA64ZFR0_AES_SHIFT, FTR_UNSIGNED, ID_AA64ZFR0_AES, CAP_HWCAP, KERNEL_HWCAP_SVEAES),
+	HWCAP_CAP(SYS_ID_AA64ZFR0_EL1, ID_AA64ZFR0_AES_SHIFT, FTR_UNSIGNED, ID_AA64ZFR0_AES_PMULL, CAP_HWCAP, KERNEL_HWCAP_SVEPMULL),
+	HWCAP_CAP(SYS_ID_AA64ZFR0_EL1, ID_AA64ZFR0_BITPERM_SHIFT, FTR_UNSIGNED, ID_AA64ZFR0_BITPERM, CAP_HWCAP, KERNEL_HWCAP_SVEBITPERM),
+	HWCAP_CAP(SYS_ID_AA64ZFR0_EL1, ID_AA64ZFR0_SHA3_SHIFT, FTR_UNSIGNED, ID_AA64ZFR0_SHA3, CAP_HWCAP, KERNEL_HWCAP_SVESHA3),
+	HWCAP_CAP(SYS_ID_AA64ZFR0_EL1, ID_AA64ZFR0_SM4_SHIFT, FTR_UNSIGNED, ID_AA64ZFR0_SM4, CAP_HWCAP, KERNEL_HWCAP_SVESM4),
 #endif
 	HWCAP_CAP(SYS_ID_AA64PFR1_EL1, ID_AA64PFR1_SSBS_SHIFT, FTR_UNSIGNED, ID_AA64PFR1_SSBS_PSTATE_INSNS, CAP_HWCAP, KERNEL_HWCAP_SSBS),
 #ifdef CONFIG_ARM64_PTR_AUTH
diff --git a/arch/arm64/kernel/cpuinfo.c b/arch/arm64/kernel/cpuinfo.c
index 093ca53..f6f7936 100644
--- a/arch/arm64/kernel/cpuinfo.c
+++ b/arch/arm64/kernel/cpuinfo.c
@@ -86,6 +86,12 @@ static const char *const hwcap_str[] = {
 	"paca",
 	"pacg",
 	"dcpodp",
+	"sve2",
+	"sveaes",
+	"svepmull",
+	"svebitperm",
+	"svesha3",
+	"svesm4",
 	NULL
 };
 
-- 
2.1.4


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Re: [PATCH] arm64: Expose SVE2 features for userspace

[Will Deacon]

On Thu, Apr 18, 2019 at 06:41:38PM +0100, Dave Martin wrote:
> This patch provides support for reporting the presence of SVE2 and
> its optional features to userspace.
> 
> This will also enable visibility of SVE2 for guests, when KVM
> support for SVE-enabled guests is available.
> 
> Signed-off-by: Dave Martin <Dave.Martin@arm.com>

Cheers, I'll pick this up for 5.2.

Will

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Re: [PATCH] arm64: Expose SVE2 features for userspace

[Dave Martin]

On Tue, Apr 23, 2019 at 04:32:18PM +0100, Will Deacon wrote:
> On Thu, Apr 18, 2019 at 06:41:38PM +0100, Dave Martin wrote:
> > This patch provides support for reporting the presence of SVE2 and
> > its optional features to userspace.
> > 
> > This will also enable visibility of SVE2 for guests, when KVM
> > support for SVE-enabled guests is available.
> > 
> > Signed-off-by: Dave Martin <Dave.Martin@arm.com>
> 
> Cheers, I'll pick this up for 5.2.

Thanks (assuming no objection from anyone else)

---Dave

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Re: [PATCH] arm64: Expose SVE2 features for userspace

[Mark Rutland]

On Thu, Apr 18, 2019 at 06:41:38PM +0100, Dave Martin wrote:
> This patch provides support for reporting the presence of SVE2 and
> its optional features to userspace.
> 
> This will also enable visibility of SVE2 for guests, when KVM
> support for SVE-enabled guests is available.
> 
> Signed-off-by: Dave Martin <Dave.Martin@arm.com>
> ---
> 
> This patch is based on
> 
> git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git
> f645d37e281f ("Merge remote-tracking branch 'arm64/for-next/mmiowb' into for-next/core")
> 
> (for Andrew Murray's HWCAP2 support).
> 
> 
> Tested with the Arm Fast Model SVE2 plugin.
> 
> For KVM, tested with:
> 
> git://linux-arm.org/linux-dm.git sve-kvm-fixes/v2/head
> http://linux-arm.org/git?p=linux-dm.git;a=shortlog;h=refs/heads/sve-kvm-fixes/v2/head
> 
> (which is also now merged to kvmarm/next).
> 
>  Documentation/arm64/cpu-feature-registers.txt | 16 ++++++++++++++++
>  Documentation/arm64/elf_hwcaps.txt            | 24 ++++++++++++++++++++++++
>  Documentation/arm64/sve.txt                   | 17 +++++++++++++++++
>  arch/arm64/Kconfig                            |  3 +++
>  arch/arm64/include/asm/hwcap.h                |  6 ++++++
>  arch/arm64/include/asm/sysreg.h               | 14 ++++++++++++++
>  arch/arm64/include/uapi/asm/hwcap.h           |  6 ++++++
>  arch/arm64/kernel/cpufeature.c                | 17 ++++++++++++++++-
>  arch/arm64/kernel/cpuinfo.c                   |  6 ++++++
>  9 files changed, 108 insertions(+), 1 deletion(-)
> 
> diff --git a/Documentation/arm64/cpu-feature-registers.txt b/Documentation/arm64/cpu-feature-registers.txt
> index d4b4dd1f..4e47a01 100644
> --- a/Documentation/arm64/cpu-feature-registers.txt
> +++ b/Documentation/arm64/cpu-feature-registers.txt
> @@ -209,6 +209,22 @@ infrastructure:
>       | AT                           | [35-32] |    y    |
>       x--------------------------------------------------x
>  
> +  6) ID_AA64ZFR0_EL1 - SVE feature ID register 0
> +
> +     x--------------------------------------------------x
> +     | Name                         |  bits   | visible |
> +     |--------------------------------------------------|
> +     | SM4                          | [43-40] |    y    |
> +     x--------------------------------------------------x
> +     | SHA3                         | [35-32] |    y    |
> +     x--------------------------------------------------x
> +     | BitPerm                      | [19-16] |    y    |
> +     x--------------------------------------------------x
> +     | AES                          | [7-4]   |    y    |
> +     x--------------------------------------------------x
> +     | SVEVer                       | [3-0]   |    y    |
> +     x--------------------------------------------------x

Trivial nit: for consistency with all the other tables, please only use
'x' at the corners, and use '|' at the edges.

Otherwise, this looks good to me; sorry for the late style nit!

Thanks,
Mark.

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Re: [PATCH] arm64: Expose SVE2 features for userspace

[Will Deacon]

On Tue, Apr 23, 2019 at 05:28:52PM +0100, Mark Rutland wrote:
> On Thu, Apr 18, 2019 at 06:41:38PM +0100, Dave Martin wrote:
> > diff --git a/Documentation/arm64/cpu-feature-registers.txt b/Documentation/arm64/cpu-feature-registers.txt
> > index d4b4dd1f..4e47a01 100644
> > --- a/Documentation/arm64/cpu-feature-registers.txt
> > +++ b/Documentation/arm64/cpu-feature-registers.txt
> > @@ -209,6 +209,22 @@ infrastructure:
> >       | AT                           | [35-32] |    y    |
> >       x--------------------------------------------------x
> >  
> > +  6) ID_AA64ZFR0_EL1 - SVE feature ID register 0
> > +
> > +     x--------------------------------------------------x
> > +     | Name                         |  bits   | visible |
> > +     |--------------------------------------------------|
> > +     | SM4                          | [43-40] |    y    |
> > +     x--------------------------------------------------x
> > +     | SHA3                         | [35-32] |    y    |
> > +     x--------------------------------------------------x
> > +     | BitPerm                      | [19-16] |    y    |
> > +     x--------------------------------------------------x
> > +     | AES                          | [7-4]   |    y    |
> > +     x--------------------------------------------------x
> > +     | SVEVer                       | [3-0]   |    y    |
> > +     x--------------------------------------------------x
> 
> Trivial nit: for consistency with all the other tables, please only use
> 'x' at the corners, and use '|' at the edges.
> 
> Otherwise, this looks good to me; sorry for the late style nit!

I'll fix that up in my tree.

Will

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Re: [PATCH] arm64: Expose SVE2 features for userspace

[Dave Martin]

On Tue, Apr 23, 2019 at 05:30:17PM +0100, Will Deacon wrote:
> On Tue, Apr 23, 2019 at 05:28:52PM +0100, Mark Rutland wrote:
> > On Thu, Apr 18, 2019 at 06:41:38PM +0100, Dave Martin wrote:
> > > diff --git a/Documentation/arm64/cpu-feature-registers.txt b/Documentation/arm64/cpu-feature-registers.txt
> > > index d4b4dd1f..4e47a01 100644
> > > --- a/Documentation/arm64/cpu-feature-registers.txt
> > > +++ b/Documentation/arm64/cpu-feature-registers.txt
> > > @@ -209,6 +209,22 @@ infrastructure:
> > >       | AT                           | [35-32] |    y    |
> > >       x--------------------------------------------------x
> > >  
> > > +  6) ID_AA64ZFR0_EL1 - SVE feature ID register 0
> > > +
> > > +     x--------------------------------------------------x
> > > +     | Name                         |  bits   | visible |
> > > +     |--------------------------------------------------|
> > > +     | SM4                          | [43-40] |    y    |
> > > +     x--------------------------------------------------x
> > > +     | SHA3                         | [35-32] |    y    |
> > > +     x--------------------------------------------------x
> > > +     | BitPerm                      | [19-16] |    y    |
> > > +     x--------------------------------------------------x
> > > +     | AES                          | [7-4]   |    y    |
> > > +     x--------------------------------------------------x
> > > +     | SVEVer                       | [3-0]   |    y    |
> > > +     x--------------------------------------------------x
> > 
> > Trivial nit: for consistency with all the other tables, please only use
> > 'x' at the corners, and use '|' at the edges.
> > 
> > Otherwise, this looks good to me; sorry for the late style nit!
> 
> I'll fix that up in my tree.

Thanks.  I didn't even spot the difference...

Cheers
---Dave

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