diff mbox

[v8,2/4] arm: add implementation for arm-smccc

Message ID 1451912079-29258-3-git-send-email-jens.wiklander@linaro.org
State Accepted
Commit b329f95d70f3f955093e9a2b18ac1ed3587a8f73
Headers show

Commit Message

Jens Wiklander Jan. 4, 2016, 12:54 p.m. UTC
Adds implementation for arm-smccc and enables CONFIG_HAVE_SMCCC for
architectures that may support arm-smccc. It's the responsibility of the
caller to know if the SMC instruction is supported by the platform.

Reviewed-by: Lars Persson <lars.persson@axis.com>

Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>

---
 arch/arm/Kconfig             |  1 +
 arch/arm/kernel/Makefile     |  2 ++
 arch/arm/kernel/armksyms.c   |  6 +++++
 arch/arm/kernel/smccc-call.S | 62 ++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 71 insertions(+)
 create mode 100644 arch/arm/kernel/smccc-call.S

-- 
1.9.1

Comments

Andreas Dannenberg March 2, 2016, 9:26 p.m. UTC | #1
On Mon, Jan 04, 2016 at 01:54:37PM +0100, Jens Wiklander wrote:
> Adds implementation for arm-smccc and enables CONFIG_HAVE_SMCCC for

> architectures that may support arm-smccc. It's the responsibility of the

> caller to know if the SMC instruction is supported by the platform.

> 

> Reviewed-by: Lars Persson <lars.persson@axis.com>

> Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>

> 

> ---

> arch/arm/Kconfig             |  1 +

>  arch/arm/kernel/Makefile     |  2 ++

>  arch/arm/kernel/armksyms.c   |  6 +++++

>  arch/arm/kernel/smccc-call.S | 62 ++++++++++++++++++++++++++++++++++++++++++++

>  4 files changed, 71 insertions(+)

>  create mode 100644 arch/arm/kernel/smccc-call.S

> 

> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig

> index 34e1569..36b9490 100644

> --- a/arch/arm/Kconfig

> +++ b/arch/arm/Kconfig

> @@ -37,6 +37,7 @@ config ARM

>  	select HAVE_ARCH_KGDB if !CPU_ENDIAN_BE32

>  	select HAVE_ARCH_SECCOMP_FILTER if (AEABI && !OABI_COMPAT)

>  	select HAVE_ARCH_TRACEHOOK

> +	select HAVE_ARM_SMCCC if CPU_V7

>  	select HAVE_BPF_JIT

>  	select HAVE_CC_STACKPROTECTOR

>  	select HAVE_CONTEXT_TRACKING

> diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile

> index af9e59b..d2d0042 100644

> --- a/arch/arm/kernel/Makefile

> +++ b/arch/arm/kernel/Makefile

> @@ -92,4 +92,6 @@ obj-y				+= psci-call.o

>  obj-$(CONFIG_SMP)		+= psci_smp.o

>  endif

>  

> +obj-$(CONFIG_HAVE_ARM_SMCCC)	+= smccc-call.o

> +

>  extra-y := $(head-y) vmlinux.lds

> diff --git a/arch/arm/kernel/armksyms.c b/arch/arm/kernel/armksyms.c

> index f89811f..7e45f69 100644

> --- a/arch/arm/kernel/armksyms.c

> +++ b/arch/arm/kernel/armksyms.c

> @@ -16,6 +16,7 @@

>  #include <linux/syscalls.h>

>  #include <linux/uaccess.h>

>  #include <linux/io.h>

> +#include <linux/arm-smccc.h>

>  

>  #include <asm/checksum.h>

>  #include <asm/ftrace.h>

> @@ -175,3 +176,8 @@ EXPORT_SYMBOL(__gnu_mcount_nc);

>  EXPORT_SYMBOL(__pv_phys_pfn_offset);

>  EXPORT_SYMBOL(__pv_offset);

>  #endif

> +

> +#ifdef CONFIG_HAVE_ARM_SMCCC

> +EXPORT_SYMBOL(arm_smccc_smc);

> +EXPORT_SYMBOL(arm_smccc_hvc);

> +#endif

> diff --git a/arch/arm/kernel/smccc-call.S b/arch/arm/kernel/smccc-call.S

> new file mode 100644

> index 0000000..2e48b67

> --- /dev/null

> +++ b/arch/arm/kernel/smccc-call.S

> @@ -0,0 +1,62 @@

> +/*

> + * Copyright (c) 2015, Linaro Limited

> + *

> + * This software is licensed under the terms of the GNU General Public

> + * License version 2, as published by the Free Software Foundation, and

> + * may be copied, distributed, and modified under those terms.

> + *

> + * This program is distributed in the hope that it will be useful,

> + * but WITHOUT ANY WARRANTY; without even the implied warranty of

> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

> + * GNU General Public License for more details.

> + *

> + */

> +#include <linux/linkage.h>

> +

> +#include <asm/opcodes-sec.h>

> +#include <asm/opcodes-virt.h>

> +#include <asm/unwind.h>

> +

> +	/*

> +	 * Wrap c macros in asm macros to delay expansion until after the

> +	 * SMCCC asm macro is expanded.

> +	 */

> +	.macro SMCCC_SMC

> +	__SMC(0)

> +	.endm

> +

> +	.macro SMCCC_HVC

> +	__HVC(0)

> +	.endm

> +

> +	.macro SMCCC instr

> +UNWIND(	.fnstart)

> +	mov	r12, sp

> +	push	{r4-r7}

> +UNWIND(	.save	{r4-r7})

> +	ldm	r12, {r4-r7}

> +	\instr


Jens,
out of curiosity, we don't need any dsb/dmb calls here? I've rummaged
through some other code here at TI and see such barriers being included
right before the smc call. However in all fairness I also don't see such
memory calls included in arch/arm/kernel/psci-call.S that your other
patch is removing, so either they are really not needed or I didn't look
right and need to go to have my prescriptions checked.

Regards,

--
Andreas Dannenberg
Texas Instruments Inc

> +	pop	{r4-r7}

> +	ldr	r12, [sp, #(4 * 4)]

> +	stm	r12, {r0-r3}

> +	bx	lr

> +UNWIND(	.fnend)

> +	.endm

> +

> +/*

> + * void smccc_smc(unsigned long a0, unsigned long a1, unsigned long a2,

> + *		  unsigned long a3, unsigned long a4, unsigned long a5,

> + *		  unsigned long a6, unsigned long a7, struct arm_smccc_res *res)

> + */

> +ENTRY(arm_smccc_smc)

> +	SMCCC SMCCC_SMC

> +ENDPROC(arm_smccc_smc)

> +

> +/*

> + * void smccc_hvc(unsigned long a0, unsigned long a1, unsigned long a2,

> + *		  unsigned long a3, unsigned long a4, unsigned long a5,

> + *		  unsigned long a6, unsigned long a7, struct arm_smccc_res *res)

> + */

> +ENTRY(arm_smccc_hvc)

> +	SMCCC SMCCC_HVC

> +ENDPROC(arm_smccc_hvc)


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Will Deacon March 2, 2016, 9:38 p.m. UTC | #2
On Wed, Mar 02, 2016 at 03:26:28PM -0600, Andreas Dannenberg wrote:
> On Mon, Jan 04, 2016 at 01:54:37PM +0100, Jens Wiklander wrote:

> > diff --git a/arch/arm/kernel/smccc-call.S b/arch/arm/kernel/smccc-call.S

> > new file mode 100644

> > index 0000000..2e48b67

> > --- /dev/null

> > +++ b/arch/arm/kernel/smccc-call.S

> > @@ -0,0 +1,62 @@

> > +/*

> > + * Copyright (c) 2015, Linaro Limited

> > + *

> > + * This software is licensed under the terms of the GNU General Public

> > + * License version 2, as published by the Free Software Foundation, and

> > + * may be copied, distributed, and modified under those terms.

> > + *

> > + * This program is distributed in the hope that it will be useful,

> > + * but WITHOUT ANY WARRANTY; without even the implied warranty of

> > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

> > + * GNU General Public License for more details.

> > + *

> > + */

> > +#include <linux/linkage.h>

> > +

> > +#include <asm/opcodes-sec.h>

> > +#include <asm/opcodes-virt.h>

> > +#include <asm/unwind.h>

> > +

> > +	/*

> > +	 * Wrap c macros in asm macros to delay expansion until after the

> > +	 * SMCCC asm macro is expanded.

> > +	 */

> > +	.macro SMCCC_SMC

> > +	__SMC(0)

> > +	.endm

> > +

> > +	.macro SMCCC_HVC

> > +	__HVC(0)

> > +	.endm

> > +

> > +	.macro SMCCC instr

> > +UNWIND(	.fnstart)

> > +	mov	r12, sp

> > +	push	{r4-r7}

> > +UNWIND(	.save	{r4-r7})

> > +	ldm	r12, {r4-r7}

> > +	\instr

> 

> Jens,

> out of curiosity, we don't need any dsb/dmb calls here? I've rummaged

> through some other code here at TI and see such barriers being included

> right before the smc call. However in all fairness I also don't see such

> memory calls included in arch/arm/kernel/psci-call.S that your other

> patch is removing, so either they are really not needed or I didn't look

> right and need to go to have my prescriptions checked.


There are no architectural requirements for a barrier here. My understanding
of the TI code is that it was there to work around buggy firmware.

Will

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diff mbox

Patch

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 34e1569..36b9490 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -37,6 +37,7 @@  config ARM
 	select HAVE_ARCH_KGDB if !CPU_ENDIAN_BE32
 	select HAVE_ARCH_SECCOMP_FILTER if (AEABI && !OABI_COMPAT)
 	select HAVE_ARCH_TRACEHOOK
+	select HAVE_ARM_SMCCC if CPU_V7
 	select HAVE_BPF_JIT
 	select HAVE_CC_STACKPROTECTOR
 	select HAVE_CONTEXT_TRACKING
diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile
index af9e59b..d2d0042 100644
--- a/arch/arm/kernel/Makefile
+++ b/arch/arm/kernel/Makefile
@@ -92,4 +92,6 @@  obj-y				+= psci-call.o
 obj-$(CONFIG_SMP)		+= psci_smp.o
 endif
 
+obj-$(CONFIG_HAVE_ARM_SMCCC)	+= smccc-call.o
+
 extra-y := $(head-y) vmlinux.lds
diff --git a/arch/arm/kernel/armksyms.c b/arch/arm/kernel/armksyms.c
index f89811f..7e45f69 100644
--- a/arch/arm/kernel/armksyms.c
+++ b/arch/arm/kernel/armksyms.c
@@ -16,6 +16,7 @@ 
 #include <linux/syscalls.h>
 #include <linux/uaccess.h>
 #include <linux/io.h>
+#include <linux/arm-smccc.h>
 
 #include <asm/checksum.h>
 #include <asm/ftrace.h>
@@ -175,3 +176,8 @@  EXPORT_SYMBOL(__gnu_mcount_nc);
 EXPORT_SYMBOL(__pv_phys_pfn_offset);
 EXPORT_SYMBOL(__pv_offset);
 #endif
+
+#ifdef CONFIG_HAVE_ARM_SMCCC
+EXPORT_SYMBOL(arm_smccc_smc);
+EXPORT_SYMBOL(arm_smccc_hvc);
+#endif
diff --git a/arch/arm/kernel/smccc-call.S b/arch/arm/kernel/smccc-call.S
new file mode 100644
index 0000000..2e48b67
--- /dev/null
+++ b/arch/arm/kernel/smccc-call.S
@@ -0,0 +1,62 @@ 
+/*
+ * Copyright (c) 2015, Linaro Limited
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+#include <linux/linkage.h>
+
+#include <asm/opcodes-sec.h>
+#include <asm/opcodes-virt.h>
+#include <asm/unwind.h>
+
+	/*
+	 * Wrap c macros in asm macros to delay expansion until after the
+	 * SMCCC asm macro is expanded.
+	 */
+	.macro SMCCC_SMC
+	__SMC(0)
+	.endm
+
+	.macro SMCCC_HVC
+	__HVC(0)
+	.endm
+
+	.macro SMCCC instr
+UNWIND(	.fnstart)
+	mov	r12, sp
+	push	{r4-r7}
+UNWIND(	.save	{r4-r7})
+	ldm	r12, {r4-r7}
+	\instr
+	pop	{r4-r7}
+	ldr	r12, [sp, #(4 * 4)]
+	stm	r12, {r0-r3}
+	bx	lr
+UNWIND(	.fnend)
+	.endm
+
+/*
+ * void smccc_smc(unsigned long a0, unsigned long a1, unsigned long a2,
+ *		  unsigned long a3, unsigned long a4, unsigned long a5,
+ *		  unsigned long a6, unsigned long a7, struct arm_smccc_res *res)
+ */
+ENTRY(arm_smccc_smc)
+	SMCCC SMCCC_SMC
+ENDPROC(arm_smccc_smc)
+
+/*
+ * void smccc_hvc(unsigned long a0, unsigned long a1, unsigned long a2,
+ *		  unsigned long a3, unsigned long a4, unsigned long a5,
+ *		  unsigned long a6, unsigned long a7, struct arm_smccc_res *res)
+ */
+ENTRY(arm_smccc_hvc)
+	SMCCC SMCCC_HVC
+ENDPROC(arm_smccc_hvc)