[PATCH v8 3/6] firmware: smccc: Move RSI definitions to include/linux

["Aneesh Kumar K.V (Arm)" <aneesh.kumar@kernel.org>]

The RSI SMCCC function IDs describe a firmware ABI and are not arm64
architecture specific definitions. Follow-up changes need to use them from
non-arch code, including drivers/firmware/smccc and the Arm CCA guest
driver.

Move the RSI SMCCC definitions from arch/arm64/include/asm/ to
include/linux/ so they can be shared with the driver code. This also
keeps the firmware interface outside architecture code, as requested [1].

Not all helpers in rsi_cmds.h are used by architecture code. The
attestation token helper wrappers are only used by the Arm CCA guest
driver, so move them to a driver-private header under
drivers/virt/coco/arm-cca-guest/. Keep the remaining RSI command helpers,
which are shared by architecture code and drivers, in the arm64 header.

[1] https://lore.kernel.org/all/agsNO9cc7H-b0H8L@willie-the-truck

Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Aneesh Kumar K.V (Arm) <aneesh.kumar@kernel.org>
---
 arch/arm64/include/asm/rsi_cmds.h             | 75 +----------------
 .../virt/coco/arm-cca-guest/arm-cca-guest.c   |  2 +
 drivers/virt/coco/arm-cca-guest/rsi.h         | 84 +++++++++++++++++++
 .../linux/arm-smccc-rsi.h                     |  6 +-
 4 files changed, 90 insertions(+), 77 deletions(-)
 create mode 100644 drivers/virt/coco/arm-cca-guest/rsi.h
 rename arch/arm64/include/asm/rsi_smc.h => include/linux/arm-smccc-rsi.h (98%)

diff --git a/arch/arm64/include/asm/rsi_cmds.h b/arch/arm64/include/asm/rsi_cmds.h
index 2c8763876dfb..8537d0fd3da6 100644
--- a/arch/arm64/include/asm/rsi_cmds.h
+++ b/arch/arm64/include/asm/rsi_cmds.h
@@ -6,12 +6,10 @@
 #ifndef __ASM_RSI_CMDS_H
 #define __ASM_RSI_CMDS_H
 
-#include <linux/arm-smccc.h>
+#include <linux/arm-smccc-rsi.h>
 #include <linux/string.h>
 #include <asm/memory.h>
 
-#include <asm/rsi_smc.h>
-
 #define RSI_GRANULE_SHIFT		12
 #define RSI_GRANULE_SIZE		(_AC(1, UL) << RSI_GRANULE_SHIFT)
 
@@ -88,75 +86,4 @@ static inline long rsi_set_addr_range_state(phys_addr_t start,
 	return res.a0;
 }
 
-/**
- * rsi_attestation_token_init - Initialise the operation to retrieve an
- * attestation token.
- *
- * @challenge:	The challenge data to be used in the attestation token
- *		generation.
- * @size:	Size of the challenge data in bytes.
- *
- * Initialises the attestation token generation and returns an upper bound
- * on the attestation token size that can be used to allocate an adequate
- * buffer. The caller is expected to subsequently call
- * rsi_attestation_token_continue() to retrieve the attestation token data on
- * the same CPU.
- *
- * Returns:
- *  On success, returns the upper limit of the attestation report size.
- *  Otherwise, -EINVAL
- */
-static inline long
-rsi_attestation_token_init(const u8 *challenge, unsigned long size)
-{
-	struct arm_smccc_1_2_regs regs = { 0 };
-
-	/* The challenge must be at least 32bytes and at most 64bytes */
-	if (!challenge || size < 32 || size > 64)
-		return -EINVAL;
-
-	regs.a0 = SMC_RSI_ATTESTATION_TOKEN_INIT;
-	memcpy(&regs.a1, challenge, size);
-	arm_smccc_1_2_smc(&regs, &regs);
-
-	if (regs.a0 == RSI_SUCCESS)
-		return regs.a1;
-
-	return -EINVAL;
-}
-
-/**
- * rsi_attestation_token_continue - Continue the operation to retrieve an
- * attestation token.
- *
- * @granule: {I}PA of the Granule to which the token will be written.
- * @offset:  Offset within Granule to start of buffer in bytes.
- * @size:    The size of the buffer.
- * @len:     The number of bytes written to the buffer.
- *
- * Retrieves up to a RSI_GRANULE_SIZE worth of token data per call. The caller
- * is expected to call rsi_attestation_token_init() before calling this
- * function to retrieve the attestation token.
- *
- * Return:
- * * %RSI_SUCCESS     - Attestation token retrieved successfully.
- * * %RSI_INCOMPLETE  - Token generation is not complete.
- * * %RSI_ERROR_INPUT - A parameter was not valid.
- * * %RSI_ERROR_STATE - Attestation not in progress.
- */
-static inline unsigned long rsi_attestation_token_continue(phys_addr_t granule,
-							   unsigned long offset,
-							   unsigned long size,
-							   unsigned long *len)
-{
-	struct arm_smccc_res res;
-
-	arm_smccc_1_1_invoke(SMC_RSI_ATTESTATION_TOKEN_CONTINUE,
-			     granule, offset, size, 0, &res);
-
-	if (len)
-		*len = res.a1;
-	return res.a0;
-}
-
 #endif /* __ASM_RSI_CMDS_H */
diff --git a/drivers/virt/coco/arm-cca-guest/arm-cca-guest.c b/drivers/virt/coco/arm-cca-guest/arm-cca-guest.c
index 32cd038cb79b..d05acddf6c4e 100644
--- a/drivers/virt/coco/arm-cca-guest/arm-cca-guest.c
+++ b/drivers/virt/coco/arm-cca-guest/arm-cca-guest.c
@@ -14,6 +14,8 @@
 
 #include <asm/rsi.h>
 
+#include "rsi.h"
+
 /**
  * struct arm_cca_token_info - a descriptor for the token buffer.
  * @challenge:		Pointer to the challenge data
diff --git a/drivers/virt/coco/arm-cca-guest/rsi.h b/drivers/virt/coco/arm-cca-guest/rsi.h
new file mode 100644
index 000000000000..f7303f4bce17
--- /dev/null
+++ b/drivers/virt/coco/arm-cca-guest/rsi.h
@@ -0,0 +1,84 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2026 ARM Ltd.
+ */
+
+#ifndef _VIRT_COCO_RSI_H_
+#define _VIRT_COCO_RSI_H_
+
+#include <linux/arm-smccc-rsi.h>
+
+/**
+ * rsi_attestation_token_init - Initialise the operation to retrieve an
+ * attestation token.
+ *
+ * @challenge:	The challenge data to be used in the attestation token
+ *		generation.
+ * @size:	Size of the challenge data in bytes.
+ *
+ * Initialises the attestation token generation and returns an upper bound
+ * on the attestation token size that can be used to allocate an adequate
+ * buffer. The caller is expected to subsequently call
+ * rsi_attestation_token_continue() to retrieve the attestation token data on
+ * the same CPU.
+ *
+ * Returns:
+ *  On success, returns the upper limit of the attestation report size.
+ *  Otherwise, -EINVAL
+ */
+static inline long
+rsi_attestation_token_init(const u8 *challenge, unsigned long size)
+{
+	struct arm_smccc_1_2_regs regs = { 0 };
+
+	/* The challenge must be at least 32bytes and at most 64bytes */
+	if (!challenge || size < 32 || size > 64)
+		return -EINVAL;
+
+	regs.a0 = SMC_RSI_ATTESTATION_TOKEN_INIT;
+	memcpy(&regs.a1, challenge, size);
+	arm_smccc_1_2_smc(&regs, &regs);
+
+	if (regs.a0 == RSI_SUCCESS)
+		return regs.a1;
+
+	return -EINVAL;
+}
+
+/**
+ * rsi_attestation_token_continue - Continue the operation to retrieve an
+ * attestation token.
+ *
+ * @granule: {I}PA of the Granule to which the token will be written.
+ * @offset:  Offset within Granule to start of buffer in bytes.
+ * @size:    The size of the buffer.
+ * @len:     The number of bytes written to the buffer.
+ *
+ * Retrieves up to a RSI_GRANULE_SIZE worth of token data per call. The caller
+ * is expected to call rsi_attestation_token_init() before calling this
+ * function to retrieve the attestation token.
+ *
+ * Return:
+ * * %RSI_SUCCESS     - Attestation token retrieved successfully.
+ * * %RSI_INCOMPLETE  - Token generation is not complete.
+ * * %RSI_ERROR_INPUT - A parameter was not valid.
+ * * %RSI_ERROR_STATE - Attestation not in progress.
+ */
+static inline unsigned long rsi_attestation_token_continue(phys_addr_t granule,
+							   unsigned long offset,
+							   unsigned long size,
+							   unsigned long *len)
+{
+	struct arm_smccc_res res;
+
+	arm_smccc_1_1_invoke(SMC_RSI_ATTESTATION_TOKEN_CONTINUE,
+			     granule, offset, size, 0, &res);
+
+	if (len)
+		*len = res.a1;
+	return res.a0;
+}
+
+
+
+#endif
diff --git a/arch/arm64/include/asm/rsi_smc.h b/include/linux/arm-smccc-rsi.h
similarity index 98%
rename from arch/arm64/include/asm/rsi_smc.h
rename to include/linux/arm-smccc-rsi.h
index e19253f96c94..fddb77986f70 100644
--- a/arch/arm64/include/asm/rsi_smc.h
+++ b/include/linux/arm-smccc-rsi.h
@@ -3,8 +3,8 @@
  * Copyright (C) 2023 ARM Ltd.
  */
 
-#ifndef __ASM_RSI_SMC_H_
-#define __ASM_RSI_SMC_H_
+#ifndef __LINUX_ARM_SMCCC_RSI_H_
+#define __LINUX_ARM_SMCCC_RSI_H_
 
 #include <linux/arm-smccc.h>
 
@@ -190,4 +190,4 @@ struct realm_config {
  */
 #define SMC_RSI_HOST_CALL			SMC_RSI_FID(0x199)
 
-#endif /* __ASM_RSI_SMC_H_ */
+#endif /* __LINUX_ARM_SMCCC_RSI_H_ */
-- 
2.43.0