ARM SMC Calling Convention interface

Switch to use a generic interface for issuing SMC/HVC based on ARM SMC Calling Convention. Removes now the now unused psci-call.S.

Signed-off-by Jens Wiklander <[email protected]>

Acked-by Will Deacon <[email protected]>

---
 arch/arm/kernel/Makefile      |  1 -
 arch/arm/kernel/psci-call.S   | 31 -------------------------------
 arch/arm64/kernel/Makefile    |  2 +-
 arch/arm64/kernel/psci-call.S | 28 ----------------------------
 drivers/firmware/psci.c       | 23 +++++++++++++++++++++--
 5 files changed, 22 insertions(+), 63 deletions(-)
 delete mode 100644 arch/arm/kernel/psci-call.S
 delete mode 100644 arch/arm64/kernel/psci-call.S

arch/arm/kernel/Makefile +0 -1

index d2d0042..80856de 100644
@@ -88,7 +88,6 @@ obj-$(CONFIG_EARLY_PRINTK)	+= early_printk.o
 
 obj-$(CONFIG_ARM_VIRT_EXT)	+= hyp-stub.o
 ifeq ($(CONFIG_ARM_PSCI),y)
-obj-y				+= psci-call.o
 obj-$(CONFIG_SMP)		+= psci_smp.o
 endif
 

arch/arm/kernel/psci-call.S deleted +0 -31

deleted file mode 100644
index a78e9e1..0000000
@@ -1,31 +0,0 @@
-/*
- * 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.
- *
- * 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.
- *
- * Copyright (C) 2015 ARM Limited
- *
- * Author: Mark Rutland <[email protected]>
- */
-
-#include <linux/linkage.h>
-
-#include <asm/opcodes-sec.h>
-#include <asm/opcodes-virt.h>
-
-/* int __invoke_psci_fn_hvc(u32 function_id, u32 arg0, u32 arg1, u32 arg2) */
-ENTRY(__invoke_psci_fn_hvc)
-	__HVC(0)
-	bx	lr
-ENDPROC(__invoke_psci_fn_hvc)
-
-/* int __invoke_psci_fn_smc(u32 function_id, u32 arg0, u32 arg1, u32 arg2) */
-ENTRY(__invoke_psci_fn_smc)
-	__SMC(0)
-	bx	lr
-ENDPROC(__invoke_psci_fn_smc)

arch/arm64/kernel/Makefile +1 -1

index 16d24a4..02893fa 100644
@@ -15,7 +15,7 @@ CFLAGS_REMOVE_return_address.o = -pg
 arm64-obj-y		:= debug-monitors.o entry.o irq.o fpsimd.o		\
 			   entry-fpsimd.o process.o ptrace.o setup.o signal.o	\
 			   sys.o stacktrace.o time.o traps.o io.o vdso.o	\
-			   hyp-stub.o psci.o psci-call.o cpu_ops.o insn.o	\
+			   hyp-stub.o psci.o cpu_ops.o insn.o	\
 			   return_address.o cpuinfo.o cpu_errata.o		\
 			   cpufeature.o alternative.o cacheinfo.o		\
 			   smp.o smp_spin_table.o topology.o smccc-call.o

arch/arm64/kernel/psci-call.S deleted +0 -28

deleted file mode 100644
index cf83e61..0000000
@@ -1,28 +0,0 @@
-/*
- * 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.
- *
- * 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.
- *
- * Copyright (C) 2015 ARM Limited
- *
- * Author: Will Deacon <[email protected]>
- */
-
-#include <linux/linkage.h>
-
-/* int __invoke_psci_fn_hvc(u64 function_id, u64 arg0, u64 arg1, u64 arg2) */
-ENTRY(__invoke_psci_fn_hvc)
-	hvc	#0
-	ret
-ENDPROC(__invoke_psci_fn_hvc)
-
-/* int __invoke_psci_fn_smc(u64 function_id, u64 arg0, u64 arg1, u64 arg2) */
-ENTRY(__invoke_psci_fn_smc)
-	smc	#0
-	ret
-ENDPROC(__invoke_psci_fn_smc)

drivers/firmware/psci.c +21 -2

index 42700f0..9c55d11 100644
@@ -19,6 +19,7 @@
 #include <linux/pm.h>
 #include <linux/printk.h>
 #include <linux/psci.h>
+#include <linux/arm-smccc.h>
 #include <linux/reboot.h>
 
 #include <uapi/linux/psci.h>

@@ -56,8 +57,6 @@ struct psci_operations psci_ops;
 
 typedef unsigned long (psci_fn)(unsigned long, unsigned long,
 				unsigned long, unsigned long);
-asmlinkage psci_fn __invoke_psci_fn_hvc;
-asmlinkage psci_fn __invoke_psci_fn_smc;
 static psci_fn *invoke_psci_fn;
 
 enum psci_function {

@@ -70,6 +69,26 @@ enum psci_function {
 
 static u32 psci_function_id[PSCI_FN_MAX];
 
+static unsigned long __invoke_psci_fn_hvc(unsigned long function_id,
+			unsigned long arg0, unsigned long arg1,
+			unsigned long arg2)
+{
+	struct arm_smccc_res res;
+
+	arm_smccc_hvc(function_id, arg0, arg1, arg2, 0, 0, 0, 0, &res);
+	return res.a0;
+}
+
+static unsigned long __invoke_psci_fn_smc(unsigned long function_id,
+			unsigned long arg0, unsigned long arg1,
+			unsigned long arg2)
+{
+	struct arm_smccc_res res;
+
+	arm_smccc_smc(function_id, arg0, arg1, arg2, 0, 0, 0, 0, &res);
+	return res.a0;
+}
+
 static int psci_to_linux_errno(int errno)
 {
 	switch (errno) {

Signature · 1 line

1.9.1

Switch to use a generic interface for issuing SMC/HVC based on ARM SMC Calling Convention. Removes now the now unused psci-call.S.

Signed-off-by Jens Wiklander <[email protected]>

Acked-by Will Deacon <[email protected]>

---
 arch/arm/kernel/Makefile      |  1 -
 arch/arm/kernel/psci-call.S   | 31 -------------------------------
 arch/arm64/kernel/Makefile    |  2 +-
 arch/arm64/kernel/psci-call.S | 28 ----------------------------
 drivers/firmware/psci.c       | 23 +++++++++++++++++++++--
 5 files changed, 22 insertions(+), 63 deletions(-)
 delete mode 100644 arch/arm/kernel/psci-call.S
 delete mode 100644 arch/arm64/kernel/psci-call.S

drivers/firmware/psci.c +10 -0

+static unsigned long __invoke_psci_fn_hvc(unsigned long function_id,
+			unsigned long arg0, unsigned long arg1,
+			unsigned long arg2)
+{
+	struct arm_smccc_res res;
+
+	arm_smccc_hvc(function_id, arg0, arg1, arg2, 0, 0, 0, 0, &res);
+	return res.a0;
+}
+

Hi Jens,

Quoted 5 lines · Jens Wiklander

Switch to use a generic interface for issuing SMC/HVC based on ARM SMC Calling Convention. Removes now the now unused psci-call.S.

Signed-off-by Jens Wiklander <[email protected]>

Acked-by Will Deacon <[email protected]>

Quoted 9 lines

---
 arch/arm/kernel/Makefile      |  1 -
 arch/arm/kernel/psci-call.S   | 31 -------------------------------
 arch/arm64/kernel/Makefile    |  2 +-
 arch/arm64/kernel/psci-call.S | 28 ----------------------------
 drivers/firmware/psci.c       | 23 +++++++++++++++++++++--
 5 files changed, 22 insertions(+), 63 deletions(-)
 delete mode 100644 arch/arm/kernel/psci-call.S
 delete mode 100644 arch/arm64/kernel/psci-call.S

As a heads-up, this conflicts with changes in drivers/firmware/psci.c that appeared in for v4.4-rc1.

The conflict is trivial (upstream some functions were added to the same location as the invocation functions), but even git am -3 doesn't seem to be able to fix that up automatically, so it would be good if you could rebase this to v4.4-rc1 so as to avoid that conflict.

drivers/firmware/psci.c line 23

Quoted 10 lines

drivers/firmware/psci.c +1 -0

index 42700f0..9c55d11 100644
@@ -19,6 +19,7 @@
 #include <linux/pm.h>
 #include <linux/printk.h>
 #include <linux/psci.h>
+#include <linux/arm-smccc.h>
 #include <linux/reboot.h>

Nit: please move the arm-smccc.h include to the start of the list to keep this ordered alphabetically.

Quoted 10 lines

drivers/firmware/psci.c +10 -0

+static unsigned long __invoke_psci_fn_hvc(unsigned long function_id,
+			unsigned long arg0, unsigned long arg1,
+			unsigned long arg2)
+{
+	struct arm_smccc_res res;
+
+	arm_smccc_hvc(function_id, arg0, arg1, arg2, 0, 0, 0, 0, &res);
+	return res.a0;
+}
+

drivers/firmware/psci.c enum psci_function { · line 91

Quoted 10 lines

drivers/firmware/psci.c +10 -0

+static unsigned long __invoke_psci_fn_smc(unsigned long function_id,
+			unsigned long arg0, unsigned long arg1,
+			unsigned long arg2)
+{
+	struct arm_smccc_res res;
+
+	arm_smccc_smc(function_id, arg0, arg1, arg2, 0, 0, 0, 0, &res);
+	return res.a0;
+}
+

As mentioned above, this part needs to be rebased to v4.4-rc1 to avoid conflicts.

I've given this a spin on arm64 (native and virtual) and arm (virtual). SMP bringup, hotplug, and reboot worked as expected in all cases.

Assuming you apply the fixes requested above, for the PSCI parts:

Reviewed-by Mark Rutland <[email protected]>

Tested-by Mark Rutland <[email protected]>

What's the plan for merging this? I assume this'll go via arm-soc?

Quoted 1 line

What's the plan for merging this? I assume this'll go via arm-soc?

I talked to Arnd about this and he suggested to go via Russel.

[CC'ed Daniel]

On Tue, Dec 01, 2015 at 08:44:22PM +0100, Jens Wiklander wrote:

[...]

Quoted 2 lines

Quoted 1 line

What's the plan for merging this? I assume this'll go via arm-soc?

Quoted 1 line

I talked to Arnd about this and he suggested to go via Russel.

Heads-up, this patch will conflict with:

https://patchwork.kernel.org/patch/7418351/

that goes via linux-pm tree, please let me and Daniel know how you want us to sort this out.

Quoted 8 lines · Lorenzo Pieralisi

[CC'ed Daniel]

On Tue, Dec 01, 2015 at 08:44:22PM +0100, Jens Wiklander wrote:

[...]

Quoted 2 lines

Quoted 1 line

What's the plan for merging this? I assume this'll go via arm-soc?

Quoted 8 lines

Quoted 1 line

I talked to Arnd about this and he suggested to go via Russel.

Heads-up, this patch will conflict with:

https://patchwork.kernel.org/patch/7418351/

that goes via linux-pm tree, please let me and Daniel know how you want us to sort this out.

I guess this arm-smccc patchset need to go together with that patch in some way. I've just uploaded my patches in Russels patch system, but I can stop that and try to go via the linux-pm tree instead if you think the maintainer would accept that. I'll need to ask Russel if he can ack the patches "arm/arm64: add arm-smccc" and
"arm: add implementation for arm-smccc" first though.

Would that work or do you have another idea? I'm of course happy either way as long as the patches get through. I'm new to this so any advice is appreciated.

Quoted 25 lines · Jens Wiklander

Quoted 8 lines · Lorenzo Pieralisi

[CC'ed Daniel]

On Tue, Dec 01, 2015 at 08:44:22PM +0100, Jens Wiklander wrote:

[...]

Quoted 2 lines

Quoted 1 line

What's the plan for merging this? I assume this'll go via arm-soc?

Quoted 8 lines

Quoted 1 line

I talked to Arnd about this and he suggested to go via Russel.

Heads-up, this patch will conflict with:

https://patchwork.kernel.org/patch/7418351/

that goes via linux-pm tree, please let me and Daniel know how you want us to sort this out.

I guess this arm-smccc patchset need to go together with that patch in some way. I've just uploaded my patches in Russels patch system, but I can stop that and try to go via the linux-pm tree instead if you think the maintainer would accept that. I'll need to ask Russel if he can ack the patches "arm/arm64: add arm-smccc" and
"arm: add implementation for arm-smccc" first though.

Quoted 3 lines

Would that work or do you have another idea? I'm of course happy either way as long as the patches get through. I'm new to this so any advice is appreciated.

It is really up to Daniel and Russell. If Daniel acks:

https://patchwork.kernel.org/patch/7418351/

I can easily rebase it and send it to RMK patch system (as things stand it seems the easier option), otherwise the merge conflict (which will show up in -next anyway) has to be sorted out, I am open to suggestions.

It is really up to Daniel and Russell. If Daniel acks:

https://patchwork.kernel.org/patch/7418351/

I can easily rebase it and send it to RMK patch system (as things stand it seems the easier option), otherwise the merge conflict (which will show up in -next anyway) has to be sorted out, I am open to suggestions.