[PATCHv2 0/4] arm64: SMCCC conduit cleanup

[PATCHv2 0/4] arm64: SMCCC conduit cleanup

[Mark Rutland]

Currently, the cpu errata code goes digging into PSCI internals to
discover the SMCCC conduit, using the (arguably misnamed) PSCI_CONDUIT_*
definitions. This lack of abstraction is somewhat unfortunate.

Further, the SDEI code has an almost identical set of CONDUIT_*
definitions, and the duplication is rather unfortunate.

Let's unify things behind a common set of SMCCC_CONDUIT_* definitions,
and expose the SMCCCv1.1 conduit via a new helper that hides the PSCI
driver internals.

Since v1 [1]:
* Rebase to the arm64 for-next/core branch, atop of SSBD patches
* Fold in acks

Mark.

[1] https://lkml.kernel.org/r/20180503170330.5591-1-mark.rutland at arm.com

Mark Rutland (4):
  arm/arm64: smccc/psci: add arm_smccc_1_1_get_conduit()
  arm64: errata: use arm_smccc_get_conduit()
  firmware/psci: use common SMCCC_CONDUIT_*
  firmware: arm_sdei: use common SMCCC_CONDUIT_*

 arch/arm64/kernel/cpu_errata.c | 34 ++++++++++++----------------------
 arch/arm64/kernel/sdei.c       |  3 ++-
 drivers/firmware/arm_sdei.c    | 12 ++++++------
 drivers/firmware/psci.c        | 24 ++++++++++++++++--------
 include/linux/arm-smccc.h      | 16 ++++++++++++++++
 include/linux/arm_sdei.h       |  6 ------
 include/linux/psci.h           |  9 ++-------
 7 files changed, 54 insertions(+), 50 deletions(-)

-- 
2.11.0

[PATCHv2 1/4] arm/arm64: smccc/psci: add arm_smccc_1_1_get_conduit()

[Mark Rutland]

SMCCC callers are currently amassing a collection of enums for the SMCCC
conduit, and are having to dig into the PSCI driver's internals in order
to figure out what to do.

Let's clean this up, with common SMCCC_CONDUIT_* definitions, and an
arm_smccc_1_1_get_conduit() helper that abstracts the PSCI driver's
internal state.

We can kill off the PSCI_CONDUIT_* definitions once we've migrated users
over to the new interface.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
---
 drivers/firmware/psci.c   | 15 +++++++++++++++
 include/linux/arm-smccc.h | 16 ++++++++++++++++
 2 files changed, 31 insertions(+)

diff --git a/drivers/firmware/psci.c b/drivers/firmware/psci.c
index c80ec1d03274..d855c20de663 100644
--- a/drivers/firmware/psci.c
+++ b/drivers/firmware/psci.c
@@ -64,6 +64,21 @@ struct psci_operations psci_ops = {
 	.smccc_version = SMCCC_VERSION_1_0,
 };
 
+enum arm_smccc_conduit arm_smccc_1_1_get_conduit(void)
+{
+	if (psci_ops.smccc_version < SMCCC_VERSION_1_1)
+		return SMCCC_CONDUIT_NONE;
+
+	switch (psci_ops.conduit) {
+	case PSCI_CONDUIT_SMC:
+		return SMCCC_CONDUIT_SMC;
+	case PSCI_CONDUIT_HVC:
+		return SMCCC_CONDUIT_HVC;
+	default:
+		return SMCCC_CONDUIT_NONE;
+	}
+}
+
 typedef unsigned long (psci_fn)(unsigned long, unsigned long,
 				unsigned long, unsigned long);
 static psci_fn *invoke_psci_fn;
diff --git a/include/linux/arm-smccc.h b/include/linux/arm-smccc.h
index ca1d2cc2cdfa..947f60f5e71e 100644
--- a/include/linux/arm-smccc.h
+++ b/include/linux/arm-smccc.h
@@ -89,6 +89,22 @@
 
 #include <linux/linkage.h>
 #include <linux/types.h>
+
+enum arm_smccc_conduit {
+	SMCCC_CONDUIT_NONE,
+	SMCCC_CONDUIT_SMC,
+	SMCCC_CONDUIT_HVC,
+};
+
+/**
+ * arm_smccc_1_1_get_conduit()
+ *
+ * Returns the conduit to be used for SMCCCv1.1 or later.
+ *
+ * When SMCCCv1.1 is not present, returns SMCCC_CONDUIT_NONE.
+ */
+enum arm_smccc_conduit arm_smccc_1_1_get_conduit(void);
+
 /**
  * struct arm_smccc_res - Result from SMC/HVC call
  * @a0-a3 result values from registers 0 to 3
-- 
2.11.0

[PATCHv2 2/4] arm64: errata: use arm_smccc_get_conduit()

[Mark Rutland]

Now that we have arm_smccc_get_conduit(), we can hide the PSCI
implementation details from the arm64 cpu errata code, so let's do so.

As arm_smccc_get_conduit() implicitly checks that the SMCCC version is
at least SMCCC_VERSION_1_1, we no longer need to check this explicitly
where switch statements have a default case.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
---
 arch/arm64/kernel/cpu_errata.c | 34 ++++++++++++----------------------
 1 file changed, 12 insertions(+), 22 deletions(-)

diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c
index cf37ca6fa5f2..0d744b47fd63 100644
--- a/arch/arm64/kernel/cpu_errata.c
+++ b/arch/arm64/kernel/cpu_errata.c
@@ -156,9 +156,7 @@ static void  install_bp_hardening_cb(const struct arm64_cpu_capabilities *entry,
 	__install_bp_hardening_cb(fn, hyp_vecs_start, hyp_vecs_end);
 }
 
-#include <uapi/linux/psci.h>
 #include <linux/arm-smccc.h>
-#include <linux/psci.h>
 
 static void call_smc_arch_workaround_1(void)
 {
@@ -193,11 +191,8 @@ enable_smccc_arch_workaround_1(const struct arm64_cpu_capabilities *entry)
 	if (!entry->matches(entry, SCOPE_LOCAL_CPU))
 		return;
 
-	if (psci_ops.smccc_version == SMCCC_VERSION_1_0)
-		return;
-
-	switch (psci_ops.conduit) {
-	case PSCI_CONDUIT_HVC:
+	switch (arm_smccc_1_1_get_conduit()) {
+	case SMCCC_CONDUIT_HVC:
 		arm_smccc_1_1_hvc(ARM_SMCCC_ARCH_FEATURES_FUNC_ID,
 				  ARM_SMCCC_ARCH_WORKAROUND_1, &res);
 		if ((int)res.a0 < 0)
@@ -208,7 +203,7 @@ enable_smccc_arch_workaround_1(const struct arm64_cpu_capabilities *entry)
 		smccc_end = NULL;
 		break;
 
-	case PSCI_CONDUIT_SMC:
+	case SMCCC_CONDUIT_SMC:
 		arm_smccc_1_1_smc(ARM_SMCCC_ARCH_FEATURES_FUNC_ID,
 				  ARM_SMCCC_ARCH_WORKAROUND_1, &res);
 		if ((int)res.a0 < 0)
@@ -275,11 +270,11 @@ void __init arm64_update_smccc_conduit(struct alt_instr *alt,
 
 	BUG_ON(nr_inst != 1);
 
-	switch (psci_ops.conduit) {
-	case PSCI_CONDUIT_HVC:
+	switch (arm_smccc_1_1_get_conduit()) {
+	case SMCCC_CONDUIT_HVC:
 		insn = aarch64_insn_get_hvc_value();
 		break;
-	case PSCI_CONDUIT_SMC:
+	case SMCCC_CONDUIT_SMC:
 		insn = aarch64_insn_get_smc_value();
 		break;
 	default:
@@ -305,12 +300,12 @@ void __init arm64_enable_wa2_handling(struct alt_instr *alt,
 
 void arm64_set_ssbd_mitigation(bool state)
 {
-	switch (psci_ops.conduit) {
-	case PSCI_CONDUIT_HVC:
+	switch (arm_smccc_1_1_get_conduit()) {
+	case SMCCC_CONDUIT_HVC:
 		arm_smccc_1_1_hvc(ARM_SMCCC_ARCH_WORKAROUND_2, state, NULL);
 		break;
 
-	case PSCI_CONDUIT_SMC:
+	case SMCCC_CONDUIT_SMC:
 		arm_smccc_1_1_smc(ARM_SMCCC_ARCH_WORKAROUND_2, state, NULL);
 		break;
 
@@ -329,18 +324,13 @@ static bool has_ssbd_mitigation(const struct arm64_cpu_capabilities *entry,
 
 	WARN_ON(scope != SCOPE_LOCAL_CPU || preemptible());
 
-	if (psci_ops.smccc_version == SMCCC_VERSION_1_0) {
-		ssbd_state = ARM64_SSBD_UNKNOWN;
-		return false;
-	}
-
-	switch (psci_ops.conduit) {
-	case PSCI_CONDUIT_HVC:
+	switch (arm_smccc_1_1_get_conduit()) {
+	case SMCCC_CONDUIT_HVC:
 		arm_smccc_1_1_hvc(ARM_SMCCC_ARCH_FEATURES_FUNC_ID,
 				  ARM_SMCCC_ARCH_WORKAROUND_2, &res);
 		break;
 
-	case PSCI_CONDUIT_SMC:
+	case SMCCC_CONDUIT_SMC:
 		arm_smccc_1_1_smc(ARM_SMCCC_ARCH_FEATURES_FUNC_ID,
 				  ARM_SMCCC_ARCH_WORKAROUND_2, &res);
 		break;
-- 
2.11.0

[PATCHv2 3/4] firmware/psci: use common SMCCC_CONDUIT_*

[Mark Rutland]

Now that we have common SMCCC_CONDUIT_* definitions, migrate the PSCI
code over to them, and kill off the old PSCI_CONDUIT_* definitions.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
---
 drivers/firmware/psci.c | 25 +++++++++----------------
 include/linux/psci.h    |  9 ++-------
 2 files changed, 11 insertions(+), 23 deletions(-)

diff --git a/drivers/firmware/psci.c b/drivers/firmware/psci.c
index d855c20de663..6d7d3ccc3a39 100644
--- a/drivers/firmware/psci.c
+++ b/drivers/firmware/psci.c
@@ -60,7 +60,7 @@ bool psci_tos_resident_on(int cpu)
 }
 
 struct psci_operations psci_ops = {
-	.conduit = PSCI_CONDUIT_NONE,
+	.conduit = SMCCC_CONDUIT_NONE,
 	.smccc_version = SMCCC_VERSION_1_0,
 };
 
@@ -69,14 +69,7 @@ enum arm_smccc_conduit arm_smccc_1_1_get_conduit(void)
 	if (psci_ops.smccc_version < SMCCC_VERSION_1_1)
 		return SMCCC_CONDUIT_NONE;
 
-	switch (psci_ops.conduit) {
-	case PSCI_CONDUIT_SMC:
-		return SMCCC_CONDUIT_SMC;
-	case PSCI_CONDUIT_HVC:
-		return SMCCC_CONDUIT_HVC;
-	default:
-		return SMCCC_CONDUIT_NONE;
-	}
+	return psci_ops.conduit;
 }
 
 typedef unsigned long (psci_fn)(unsigned long, unsigned long,
@@ -228,13 +221,13 @@ static unsigned long psci_migrate_info_up_cpu(void)
 			      0, 0, 0);
 }
 
-static void set_conduit(enum psci_conduit conduit)
+static void set_conduit(enum arm_smccc_conduit conduit)
 {
 	switch (conduit) {
-	case PSCI_CONDUIT_HVC:
+	case SMCCC_CONDUIT_HVC:
 		invoke_psci_fn = __invoke_psci_fn_hvc;
 		break;
-	case PSCI_CONDUIT_SMC:
+	case SMCCC_CONDUIT_SMC:
 		invoke_psci_fn = __invoke_psci_fn_smc;
 		break;
 	default:
@@ -256,9 +249,9 @@ static int get_set_conduit_method(struct device_node *np)
 	}
 
 	if (!strcmp("hvc", method)) {
-		set_conduit(PSCI_CONDUIT_HVC);
+		set_conduit(SMCCC_CONDUIT_HVC);
 	} else if (!strcmp("smc", method)) {
-		set_conduit(PSCI_CONDUIT_SMC);
+		set_conduit(SMCCC_CONDUIT_SMC);
 	} else {
 		pr_warn("invalid \"method\" property: %s\n", method);
 		return -EINVAL;
@@ -714,9 +707,9 @@ int __init psci_acpi_init(void)
 	pr_info("probing for conduit method from ACPI.\n");
 
 	if (acpi_psci_use_hvc())
-		set_conduit(PSCI_CONDUIT_HVC);
+		set_conduit(SMCCC_CONDUIT_HVC);
 	else
-		set_conduit(PSCI_CONDUIT_SMC);
+		set_conduit(SMCCC_CONDUIT_SMC);
 
 	return psci_probe();
 }
diff --git a/include/linux/psci.h b/include/linux/psci.h
index 8b1b3b5935ab..affcd2128df8 100644
--- a/include/linux/psci.h
+++ b/include/linux/psci.h
@@ -14,6 +14,7 @@
 #ifndef __LINUX_PSCI_H
 #define __LINUX_PSCI_H
 
+#include <linux/arm-smccc.h>
 #include <linux/init.h>
 #include <linux/types.h>
 
@@ -25,12 +26,6 @@ bool psci_tos_resident_on(int cpu);
 int psci_cpu_init_idle(unsigned int cpu);
 int psci_cpu_suspend_enter(unsigned long index);
 
-enum psci_conduit {
-	PSCI_CONDUIT_NONE,
-	PSCI_CONDUIT_SMC,
-	PSCI_CONDUIT_HVC,
-};
-
 enum smccc_version {
 	SMCCC_VERSION_1_0,
 	SMCCC_VERSION_1_1,
@@ -45,7 +40,7 @@ struct psci_operations {
 	int (*affinity_info)(unsigned long target_affinity,
 			unsigned long lowest_affinity_level);
 	int (*migrate_info_type)(void);
-	enum psci_conduit conduit;
+	enum arm_smccc_conduit conduit;
 	enum smccc_version smccc_version;
 };
 
-- 
2.11.0

[PATCHv2 4/4] firmware: arm_sdei: use common SMCCC_CONDUIT_*

[Mark Rutland]

Now that we have common definitions for SMCCC conduits, move the SDEI
code over to them, and remove the SDEI-specific definitions.

There should be no functional change as a result of this patch.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: James Morse <james.morse@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
---
 arch/arm64/kernel/sdei.c    |  3 ++-
 drivers/firmware/arm_sdei.c | 12 ++++++------
 include/linux/arm_sdei.h    |  6 ------
 3 files changed, 8 insertions(+), 13 deletions(-)

diff --git a/arch/arm64/kernel/sdei.c b/arch/arm64/kernel/sdei.c
index 6b8d90d5ceae..a3be67ae8a88 100644
--- a/arch/arm64/kernel/sdei.c
+++ b/arch/arm64/kernel/sdei.c
@@ -2,6 +2,7 @@
 // Copyright (C) 2017 Arm Ltd.
 #define pr_fmt(fmt) "sdei: " fmt
 
+#include <linux/arm-smccc.h>
 #include <linux/arm_sdei.h>
 #include <linux/hardirq.h>
 #include <linux/irqflags.h>
@@ -125,7 +126,7 @@ unsigned long sdei_arch_get_entry_point(int conduit)
 			return 0;
 	}
 
-	sdei_exit_mode = (conduit == CONDUIT_HVC) ? SDEI_EXIT_HVC : SDEI_EXIT_SMC;
+	sdei_exit_mode = (conduit == SMCCC_CONDUIT_HVC) ? SDEI_EXIT_HVC : SDEI_EXIT_SMC;
 
 #ifdef CONFIG_UNMAP_KERNEL_AT_EL0
 	if (arm64_kernel_unmapped_at_el0()) {
diff --git a/drivers/firmware/arm_sdei.c b/drivers/firmware/arm_sdei.c
index 1ea71640fdc2..1357dbd7c7fc 100644
--- a/drivers/firmware/arm_sdei.c
+++ b/drivers/firmware/arm_sdei.c
@@ -896,29 +896,29 @@ static int sdei_get_conduit(struct platform_device *pdev)
 	if (np) {
 		if (of_property_read_string(np, "method", &method)) {
 			pr_warn("missing \"method\" property\n");
-			return CONDUIT_INVALID;
+			return SMCCC_CONDUIT_NONE;
 		}
 
 		if (!strcmp("hvc", method)) {
 			sdei_firmware_call = &sdei_smccc_hvc;
-			return CONDUIT_HVC;
+			return SMCCC_CONDUIT_HVC;
 		} else if (!strcmp("smc", method)) {
 			sdei_firmware_call = &sdei_smccc_smc;
-			return CONDUIT_SMC;
+			return SMCCC_CONDUIT_SMC;
 		}
 
 		pr_warn("invalid \"method\" property: %s\n", method);
 	} else if (IS_ENABLED(CONFIG_ACPI) && !acpi_disabled) {
 		if (acpi_psci_use_hvc()) {
 			sdei_firmware_call = &sdei_smccc_hvc;
-			return CONDUIT_HVC;
+			return SMCCC_CONDUIT_HVC;
 		} else {
 			sdei_firmware_call = &sdei_smccc_smc;
-			return CONDUIT_SMC;
+			return SMCCC_CONDUIT_SMC;
 		}
 	}
 
-	return CONDUIT_INVALID;
+	return SMCCC_CONDUIT_NONE;
 }
 
 static int sdei_probe(struct platform_device *pdev)
diff --git a/include/linux/arm_sdei.h b/include/linux/arm_sdei.h
index 942afbd544b7..21e337d99fa6 100644
--- a/include/linux/arm_sdei.h
+++ b/include/linux/arm_sdei.h
@@ -5,12 +5,6 @@
 
 #include <uapi/linux/arm_sdei.h>
 
-enum sdei_conduit_types {
-	CONDUIT_INVALID = 0,
-	CONDUIT_SMC,
-	CONDUIT_HVC,
-};
-
 #include <asm/sdei.h>
 
 /* Arch code should override this to set the entry point from firmware... */
-- 
2.11.0

[PATCHv2 0/4] arm64: SMCCC conduit cleanup

[Catalin Marinas]

On Thu, May 31, 2018 at 06:32:19PM +0100, Mark Rutland wrote:
> Mark Rutland (4):
>   arm/arm64: smccc/psci: add arm_smccc_1_1_get_conduit()
>   arm64: errata: use arm_smccc_get_conduit()
>   firmware/psci: use common SMCCC_CONDUIT_*
>   firmware: arm_sdei: use common SMCCC_CONDUIT_*

Queued for 4.18. Thanks.

-- 
Catalin

[PATCHv2 0/4] arm64: SMCCC conduit cleanup

[Russell King - ARM Linux]

On Fri, Jun 01, 2018 at 03:14:10PM +0100, Catalin Marinas wrote:
> On Thu, May 31, 2018 at 06:32:19PM +0100, Mark Rutland wrote:
> > Mark Rutland (4):
> >   arm/arm64: smccc/psci: add arm_smccc_1_1_get_conduit()
> >   arm64: errata: use arm_smccc_get_conduit()
> >   firmware/psci: use common SMCCC_CONDUIT_*
> >   firmware: arm_sdei: use common SMCCC_CONDUIT_*
> 
> Queued for 4.18. Thanks.

Have you considered how this affects the 32-bit ARM spectre stuff, which
makes use of the firmware PSCI interfaces for the workaround?

-- 
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[PATCHv2 0/4] arm64: SMCCC conduit cleanup

[Catalin Marinas]

On Fri, Jun 01, 2018 at 03:26:16PM +0100, Russell King wrote:
> On Fri, Jun 01, 2018 at 03:14:10PM +0100, Catalin Marinas wrote:
> > On Thu, May 31, 2018 at 06:32:19PM +0100, Mark Rutland wrote:
> > > Mark Rutland (4):
> > >   arm/arm64: smccc/psci: add arm_smccc_1_1_get_conduit()
> > >   arm64: errata: use arm_smccc_get_conduit()
> > >   firmware/psci: use common SMCCC_CONDUIT_*
> > >   firmware: arm_sdei: use common SMCCC_CONDUIT_*
> > 
> > Queued for 4.18. Thanks.
> 
> Have you considered how this affects the 32-bit ARM spectre stuff, which
> makes use of the firmware PSCI interfaces for the workaround?

No, I haven't. Thanks for the heads up. Talking to Mark, I think it's
best if I drop this series for now.

-- 
Catalin