[PATCH 0/5] ARM: add module autoloading support for crypto modules

[PATCH 0/5] ARM: add module autoloading support for crypto modules

[Ard Biesheuvel]

This series wires up the crypto modules that use the ARM 32-bit versions of
the ARMv8 Crypto Extensions to udev autoloading, by exposing the HWCAP2
feature bits via the CPU modalias. This is very similar to the arm64
implementation, with the notable exception that ARM has its CPU feature
definitions split across HWCAP and HWCAP2.

Given that the crypto feature bits are all exposed via HWCAP2, and considering
that there are currently no features exposed via HWCAP that are relevant to
udev module autoloading, exposing HWCAP2 only should be sufficient, at least
for now.

Note to Herbert: patches #2 - #5 all depend on #1, which requires an ack from
Russell, so please don't pull anything until #1 has been acked and/or merged.

Ard Biesheuvel (5):
  ARM: wire up HWCAP2 feature bits to the CPU modalias
  crypto: arm/aes-ce - enable module autoloading based on CPU feature
    bits
  crypto: arm/ghash-ce - enable module autoloading based on CPU feature
    bits
  crypto: arm/sha1-ce - enable module autoloading based on CPU feature
    bits
  crypto: arm/sha2-ce - enable module autoloading based on CPU feature
    bits

 arch/arm/Kconfig                  |  1 +
 arch/arm/crypto/aes-ce-glue.c     |  5 ++-
 arch/arm/crypto/ghash-ce-glue.c   |  6 ++--
 arch/arm/crypto/sha1-ce-glue.c    |  5 ++-
 arch/arm/crypto/sha2-ce-glue.c    |  5 ++-
 arch/arm/include/asm/cpufeature.h | 32 ++++++++++++++++++++
 6 files changed, 41 insertions(+), 13 deletions(-)
 create mode 100644 arch/arm/include/asm/cpufeature.h

-- 
2.7.4

[PATCH 1/5] ARM: wire up HWCAP2 feature bits to the CPU modalias

[Ard Biesheuvel]

Wire up the generic support for exposing CPU feature bits via the
modalias in /sys/device/system/cpu. This allows udev to automatically
load modules for things like crypto algorithms that are implemented
using optional instructions.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 arch/arm/Kconfig                  |  1 +
 arch/arm/include/asm/cpufeature.h | 32 ++++++++++++++++++++
 2 files changed, 33 insertions(+)

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index b5d529fdffab..1a0c6a486a9c 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -21,6 +21,7 @@ config ARM
 	select GENERIC_ALLOCATOR
 	select GENERIC_ATOMIC64 if (CPU_V7M || CPU_V6 || !CPU_32v6K || !AEABI)
 	select GENERIC_CLOCKEVENTS_BROADCAST if SMP
+	select GENERIC_CPU_AUTOPROBE
 	select GENERIC_EARLY_IOREMAP
 	select GENERIC_IDLE_POLL_SETUP
 	select GENERIC_IRQ_PROBE
diff --git a/arch/arm/include/asm/cpufeature.h b/arch/arm/include/asm/cpufeature.h
new file mode 100644
index 000000000000..19c3dddd901a
--- /dev/null
+++ b/arch/arm/include/asm/cpufeature.h
@@ -0,0 +1,32 @@
+/*
+ * Copyright (C) 2016 Linaro Ltd. <ard.biesheuvel@linaro.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef __ASM_CPUFEATURE_H
+#define __ASM_CPUFEATURE_H
+
+#include <asm/hwcap.h>
+
+/*
+ * Due to the fact that ELF_HWCAP is a 32-bit type on ARM, and given the number
+ * of optional CPU features it defines, ARM's CPU capability bits have been
+ * divided across separate elf_hwcap and elf_hwcap2 variables, each of which
+ * covers a subset of the available CPU features.
+ *
+ * Currently, only a few of those are suitable for automatic module loading
+ * (which is the primary use case of this facility) and those happen to be all
+ * covered by HWCAP2. So let's only expose those via the CPU modalias for now.
+ */
+#define MAX_CPU_FEATURES	(8 * sizeof(elf_hwcap2))
+#define cpu_feature(x)		ilog2(HWCAP2_ ## x)
+
+static inline bool cpu_have_feature(unsigned int num)
+{
+	return elf_hwcap2 & (1UL << num);
+}
+
+#endif
-- 
2.7.4

Re: [PATCH 1/5] ARM: wire up HWCAP2 feature bits to the CPU modalias

[Ard Biesheuvel]

On 18 October 2016 at 11:52, Ard Biesheuvel <ard.biesheuvel@linaro.org> wrote:
> Wire up the generic support for exposing CPU feature bits via the
> modalias in /sys/device/system/cpu. This allows udev to automatically
> load modules for things like crypto algorithms that are implemented
> using optional instructions.
>
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> ---
>  arch/arm/Kconfig                  |  1 +
>  arch/arm/include/asm/cpufeature.h | 32 ++++++++++++++++++++
>  2 files changed, 33 insertions(+)
>

Russell,

do you have any concerns regarding this patch? If not, I will drop it
into the patch system.

Herbert,

I will resend the followup patches in this series to linux-crypto@
once this prerequisite is in place

Thanks,
Ard.


> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> index b5d529fdffab..1a0c6a486a9c 100644
> --- a/arch/arm/Kconfig
> +++ b/arch/arm/Kconfig
> @@ -21,6 +21,7 @@ config ARM
>         select GENERIC_ALLOCATOR
>         select GENERIC_ATOMIC64 if (CPU_V7M || CPU_V6 || !CPU_32v6K || !AEABI)
>         select GENERIC_CLOCKEVENTS_BROADCAST if SMP
> +       select GENERIC_CPU_AUTOPROBE
>         select GENERIC_EARLY_IOREMAP
>         select GENERIC_IDLE_POLL_SETUP
>         select GENERIC_IRQ_PROBE
> diff --git a/arch/arm/include/asm/cpufeature.h b/arch/arm/include/asm/cpufeature.h
> new file mode 100644
> index 000000000000..19c3dddd901a
> --- /dev/null
> +++ b/arch/arm/include/asm/cpufeature.h
> @@ -0,0 +1,32 @@
> +/*
> + * Copyright (C) 2016 Linaro Ltd. <ard.biesheuvel@linaro.org>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + */
> +
> +#ifndef __ASM_CPUFEATURE_H
> +#define __ASM_CPUFEATURE_H
> +
> +#include <asm/hwcap.h>
> +
> +/*
> + * Due to the fact that ELF_HWCAP is a 32-bit type on ARM, and given the number
> + * of optional CPU features it defines, ARM's CPU capability bits have been
> + * divided across separate elf_hwcap and elf_hwcap2 variables, each of which
> + * covers a subset of the available CPU features.
> + *
> + * Currently, only a few of those are suitable for automatic module loading
> + * (which is the primary use case of this facility) and those happen to be all
> + * covered by HWCAP2. So let's only expose those via the CPU modalias for now.
> + */
> +#define MAX_CPU_FEATURES       (8 * sizeof(elf_hwcap2))
> +#define cpu_feature(x)         ilog2(HWCAP2_ ## x)
> +
> +static inline bool cpu_have_feature(unsigned int num)
> +{
> +       return elf_hwcap2 & (1UL << num);
> +}
> +
> +#endif
> --
> 2.7.4
>

Re: [PATCH 1/5] ARM: wire up HWCAP2 feature bits to the CPU modalias

[Russell King - ARM Linux]

On Sat, Oct 29, 2016 at 11:08:36AM +0100, Ard Biesheuvel wrote:
> On 18 October 2016 at 11:52, Ard Biesheuvel <ard.biesheuvel@linaro.org> wrote:
> > Wire up the generic support for exposing CPU feature bits via the
> > modalias in /sys/device/system/cpu. This allows udev to automatically
> > load modules for things like crypto algorithms that are implemented
> > using optional instructions.
> >
> > Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> > ---
> >  arch/arm/Kconfig                  |  1 +
> >  arch/arm/include/asm/cpufeature.h | 32 ++++++++++++++++++++
> >  2 files changed, 33 insertions(+)
> >
> 
> Russell,
> 
> do you have any concerns regarding this patch? If not, I will drop it
> into the patch system.

It's still something I need to look at... I've been offline last week,
and sort-of offline the previous week, so I'm catching up.

-- 
RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up
according to speedtest.net.

Re: [PATCH 1/5] ARM: wire up HWCAP2 feature bits to the CPU modalias

[Ard Biesheuvel]

On 31 October 2016 at 16:13, Russell King - ARM Linux
<linux@armlinux.org.uk> wrote:
> On Sat, Oct 29, 2016 at 11:08:36AM +0100, Ard Biesheuvel wrote:
>> On 18 October 2016 at 11:52, Ard Biesheuvel <ard.biesheuvel@linaro.org> wrote:
>> > Wire up the generic support for exposing CPU feature bits via the
>> > modalias in /sys/device/system/cpu. This allows udev to automatically
>> > load modules for things like crypto algorithms that are implemented
>> > using optional instructions.
>> >
>> > Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
>> > ---
>> >  arch/arm/Kconfig                  |  1 +
>> >  arch/arm/include/asm/cpufeature.h | 32 ++++++++++++++++++++
>> >  2 files changed, 33 insertions(+)
>> >
>>
>> Russell,
>>
>> do you have any concerns regarding this patch? If not, I will drop it
>> into the patch system.
>
> It's still something I need to look at... I've been offline last week,
> and sort-of offline the previous week, so I'm catching up.
>

Hi Russell,

Any thoughts yet?

Thanks,
Ard.

Re: [PATCH 1/5] ARM: wire up HWCAP2 feature bits to the CPU modalias

[Russell King - ARM Linux]

On Mon, Jan 02, 2017 at 09:06:04PM +0000, Ard Biesheuvel wrote:
> On 31 October 2016 at 16:13, Russell King - ARM Linux
> <linux@armlinux.org.uk> wrote:
> > On Sat, Oct 29, 2016 at 11:08:36AM +0100, Ard Biesheuvel wrote:
> >> On 18 October 2016 at 11:52, Ard Biesheuvel <ard.biesheuvel@linaro.org> wrote:
> >> > Wire up the generic support for exposing CPU feature bits via the
> >> > modalias in /sys/device/system/cpu. This allows udev to automatically
> >> > load modules for things like crypto algorithms that are implemented
> >> > using optional instructions.
> >> >
> >> > Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> >> > ---
> >> >  arch/arm/Kconfig                  |  1 +
> >> >  arch/arm/include/asm/cpufeature.h | 32 ++++++++++++++++++++
> >> >  2 files changed, 33 insertions(+)
> >> >
> >>
> >> Russell,
> >>
> >> do you have any concerns regarding this patch? If not, I will drop it
> >> into the patch system.
> >
> > It's still something I need to look at... I've been offline last week,
> > and sort-of offline the previous week, so I'm catching up.
> >
> 
> Hi Russell,
> 
> Any thoughts yet?

None, and the patch is well buried now that it'll take me a while to
find... back in mid-October?  Yea, I'll have to drop everything and
go digging through my mailboxes to find it... and I'm just catching
up (again) after a week and a bit's time offline - yep, it's wonderful
timing.  Sorry, no time to look at it right now, you're not the only
one wanting my attention at the moment.

Please try again in about a week's time - don't leave it a few months,
and please include the patch.

-- 
RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up
according to speedtest.net.

Re: [PATCH 1/5] ARM: wire up HWCAP2 feature bits to the CPU modalias

[Ard Biesheuvel]

On 2 January 2017 at 23:40, Russell King - ARM Linux
<linux@armlinux.org.uk> wrote:
> On Mon, Jan 02, 2017 at 09:06:04PM +0000, Ard Biesheuvel wrote:
>> On 31 October 2016 at 16:13, Russell King - ARM Linux
>> <linux@armlinux.org.uk> wrote:
>> > On Sat, Oct 29, 2016 at 11:08:36AM +0100, Ard Biesheuvel wrote:
>> >> On 18 October 2016 at 11:52, Ard Biesheuvel <ard.biesheuvel@linaro.org> wrote:
>> >> > Wire up the generic support for exposing CPU feature bits via the
>> >> > modalias in /sys/device/system/cpu. This allows udev to automatically
>> >> > load modules for things like crypto algorithms that are implemented
>> >> > using optional instructions.
>> >> >
>> >> > Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
>> >> > ---
>> >> >  arch/arm/Kconfig                  |  1 +
>> >> >  arch/arm/include/asm/cpufeature.h | 32 ++++++++++++++++++++
>> >> >  2 files changed, 33 insertions(+)
>> >> >
>> >>
>> >> Russell,
>> >>
>> >> do you have any concerns regarding this patch? If not, I will drop it
>> >> into the patch system.
>> >
>> > It's still something I need to look at... I've been offline last week,
>> > and sort-of offline the previous week, so I'm catching up.
>> >
>>
>> Hi Russell,
>>
>> Any thoughts yet?
>
> None, and the patch is well buried now that it'll take me a while to
> find... back in mid-October?  Yea, I'll have to drop everything and
> go digging through my mailboxes to find it... and I'm just catching
> up (again) after a week and a bit's time offline - yep, it's wonderful
> timing.  Sorry, no time to look at it right now, you're not the only
> one wanting my attention at the moment.
>

No worries. It is not exactly urgent, but it is a useful enhancement
nonetheless.

> Please try again in about a week's time - don't leave it a few months,
> and please include the patch.
>

OK

[PATCH 2/5] crypto: arm/aes-ce - enable module autoloading based on CPU feature bits

[Ard Biesheuvel]

Make the module autoloadable by tying it to the CPU feature bit that
describes whether the optional instructions it relies on are implemented
by the current CPU.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 arch/arm/crypto/aes-ce-glue.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/arch/arm/crypto/aes-ce-glue.c b/arch/arm/crypto/aes-ce-glue.c
index aef022a87c53..5b1af6f8b2b5 100644
--- a/arch/arm/crypto/aes-ce-glue.c
+++ b/arch/arm/crypto/aes-ce-glue.c
@@ -14,6 +14,7 @@
 #include <crypto/aes.h>
 #include <crypto/ablk_helper.h>
 #include <crypto/algapi.h>
+#include <linux/cpufeature.h>
 #include <linux/module.h>
 #include <crypto/xts.h>
 
@@ -515,8 +516,6 @@ static struct crypto_alg aes_algs[] = { {
 
 static int __init aes_init(void)
 {
-	if (!(elf_hwcap2 & HWCAP2_AES))
-		return -ENODEV;
 	return crypto_register_algs(aes_algs, ARRAY_SIZE(aes_algs));
 }
 
@@ -525,5 +524,5 @@ static void __exit aes_exit(void)
 	crypto_unregister_algs(aes_algs, ARRAY_SIZE(aes_algs));
 }
 
-module_init(aes_init);
+module_cpu_feature_match(AES, aes_init);
 module_exit(aes_exit);
-- 
2.7.4

[PATCH 3/5] crypto: arm/ghash-ce - enable module autoloading based on CPU feature bits

[Ard Biesheuvel]

Make the module autoloadable by tying it to the CPU feature bit that
describes whether the optional instructions it relies on are implemented
by the current CPU.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 arch/arm/crypto/ghash-ce-glue.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/arch/arm/crypto/ghash-ce-glue.c b/arch/arm/crypto/ghash-ce-glue.c
index 7546b3c02466..6bac8bea9f1e 100644
--- a/arch/arm/crypto/ghash-ce-glue.c
+++ b/arch/arm/crypto/ghash-ce-glue.c
@@ -15,6 +15,7 @@
 #include <crypto/cryptd.h>
 #include <crypto/internal/hash.h>
 #include <crypto/gf128mul.h>
+#include <linux/cpufeature.h>
 #include <linux/crypto.h>
 #include <linux/module.h>
 
@@ -311,9 +312,6 @@ static int __init ghash_ce_mod_init(void)
 {
 	int err;
 
-	if (!(elf_hwcap2 & HWCAP2_PMULL))
-		return -ENODEV;
-
 	err = crypto_register_shash(&ghash_alg);
 	if (err)
 		return err;
@@ -334,5 +332,5 @@ static void __exit ghash_ce_mod_exit(void)
 	crypto_unregister_shash(&ghash_alg);
 }
 
-module_init(ghash_ce_mod_init);
+module_cpu_feature_match(PMULL, ghash_ce_mod_init);
 module_exit(ghash_ce_mod_exit);
-- 
2.7.4

[PATCH 4/5] crypto: arm/sha1-ce - enable module autoloading based on CPU feature bits

[Ard Biesheuvel]

Make the module autoloadable by tying it to the CPU feature bit that
describes whether the optional instructions it relies on are implemented
by the current CPU.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 arch/arm/crypto/sha1-ce-glue.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/arch/arm/crypto/sha1-ce-glue.c b/arch/arm/crypto/sha1-ce-glue.c
index 80bc2fcd241a..555f72b5e659 100644
--- a/arch/arm/crypto/sha1-ce-glue.c
+++ b/arch/arm/crypto/sha1-ce-glue.c
@@ -11,6 +11,7 @@
 #include <crypto/internal/hash.h>
 #include <crypto/sha.h>
 #include <crypto/sha1_base.h>
+#include <linux/cpufeature.h>
 #include <linux/crypto.h>
 #include <linux/module.h>
 
@@ -82,8 +83,6 @@ static struct shash_alg alg = {
 
 static int __init sha1_ce_mod_init(void)
 {
-	if (!(elf_hwcap2 & HWCAP2_SHA1))
-		return -ENODEV;
 	return crypto_register_shash(&alg);
 }
 
@@ -92,5 +91,5 @@ static void __exit sha1_ce_mod_fini(void)
 	crypto_unregister_shash(&alg);
 }
 
-module_init(sha1_ce_mod_init);
+module_cpu_feature_match(SHA1, sha1_ce_mod_init);
 module_exit(sha1_ce_mod_fini);
-- 
2.7.4

[PATCH 5/5] crypto: arm/sha2-ce - enable module autoloading based on CPU feature bits

[Ard Biesheuvel]

Make the module autoloadable by tying it to the CPU feature bit that
describes whether the optional instructions it relies on are implemented
by the current CPU.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 arch/arm/crypto/sha2-ce-glue.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/arch/arm/crypto/sha2-ce-glue.c b/arch/arm/crypto/sha2-ce-glue.c
index 0755b2d657f3..df4dcef054ae 100644
--- a/arch/arm/crypto/sha2-ce-glue.c
+++ b/arch/arm/crypto/sha2-ce-glue.c
@@ -11,6 +11,7 @@
 #include <crypto/internal/hash.h>
 #include <crypto/sha.h>
 #include <crypto/sha256_base.h>
+#include <linux/cpufeature.h>
 #include <linux/crypto.h>
 #include <linux/module.h>
 
@@ -100,8 +101,6 @@ static struct shash_alg algs[] = { {
 
 static int __init sha2_ce_mod_init(void)
 {
-	if (!(elf_hwcap2 & HWCAP2_SHA2))
-		return -ENODEV;
 	return crypto_register_shashes(algs, ARRAY_SIZE(algs));
 }
 
@@ -110,5 +109,5 @@ static void __exit sha2_ce_mod_fini(void)
 	crypto_unregister_shashes(algs, ARRAY_SIZE(algs));
 }
 
-module_init(sha2_ce_mod_init);
+module_cpu_feature_match(SHA2, sha2_ce_mod_init);
 module_exit(sha2_ce_mod_fini);
-- 
2.7.4