powerpc/pseries: Add ibm,set-dynamic-indicator RTAS call support

JIRA: https://issues.redhat.com/browse/RHEL-101838

commit f60a379
Author: Haren Myneni <haren@linux.ibm.com>
Date:   Wed Apr 16 15:57:39 2025 -0700

    powerpc/pseries: Add ibm,set-dynamic-indicator RTAS call support

    The RTAS call ibm,set-dynamic-indicator is used to set the new
    indicator state identified by a location code. The current
    implementation uses rtas_set_dynamic_indicator() API provided by
    librtas library which allocates RMO buffer and issue this RTAS
    call in the user space. But /dev/mem access by the user space
    is prohibited under system lockdown.

    This patch provides an interface with new ioctl
    PAPR_DYNAMIC_INDICATOR_IOC_SET to the papr-indices character
    driver and expose this interface to the user space that is
    compatible with lockdown.

    Refer PAPR 7.3.18 ibm,set-dynamic-indicator for more
    information on this RTAS call.
    -  User input parameters to the RTAS call: location code
       string, indicator token and new state

    Expose these interfaces to user space with a /dev/papr-indices
    character device using the following programming model:
     int fd = open("/dev/papr-indices", O_RDWR);
     int ret = ioctl(fd, PAPR_DYNAMIC_INDICATOR_IOC_SET,
                    struct papr_indices_io_block)
      - The user space passes input parameters in papr_indices_io_block
        struct

    Signed-off-by: Haren Myneni <haren@linux.ibm.com>
    Tested-by: Sathvika Vasireddy <sv@linux.ibm.com>
    Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
    Link: https://patch.msgid.link/20250416225743.596462-5-haren@linux.ibm.com

Signed-off-by: Mamatha Inamdar <minamdar@redhat.com>

Author: Mamatha Inamdar

arch/powerpc/include/asm/rtas.h

@@ -338,6 +338,7 @@ extern unsigned long rtas_rmo_buf;
 
 extern struct mutex rtas_ibm_get_vpd_lock;
 extern struct mutex rtas_ibm_get_indices_lock;
+extern struct mutex rtas_ibm_set_dynamic_indicator_lock;
 
 #define GLOBAL_INTERRUPT_QUEUE 9005
 

arch/powerpc/kernel/rtas.c

@@ -78,6 +78,7 @@ EXPORT_SYMBOL(rtas_flash_term_hook);
 
 DEFINE_MUTEX(rtas_ibm_get_vpd_lock);
 DEFINE_MUTEX(rtas_ibm_get_indices_lock);
+DEFINE_MUTEX(rtas_ibm_set_dynamic_indicator_lock);
 
 /* RTAS use home made raw locking instead of spin_lock_irqsave
  * because those can be called from within really nasty contexts
@@ -1122,6 +1123,9 @@ static struct mutex *find_rtas_mutex(int token)
 	if (token == rtas_token("ibm,get-indices"))
 		return &rtas_ibm_get_indices_lock;
 
+	if (token == rtas_token("ibm,set-dynamic-indicator"))
+		return &rtas_ibm_set_dynamic_indicator_lock;
+
 	return NULL;
 }
 

arch/powerpc/platforms/pseries/papr-indices.c

@@ -20,6 +20,13 @@
 #include <uapi/asm/papr-indices.h>
 #include "papr-rtas-common.h"
 
+/*
+ * Function-specific return values for ibm,set-dynamic-indicator and
+ * ibm,get-dynamic-sensor-state RTAS calls.
+ * PAPR+ v2.13 7.3.18 and 7.3.19.
+ */
+#define RTAS_IBM_DYNAMIC_INDICE_NO_INDICATOR	-3
+
 /**
  * struct rtas_get_indices_params - Parameters (in and out) for
  *                                      ibm,get-indices.
@@ -260,6 +267,110 @@ static long papr_indices_create_handle(struct papr_indices_io_block __user *ubuf
 	return fd;
 }
 
+/*
+ * Create work area with the input parameters. This function is used
+ * for both ibm,set-dynamic-indicator and ibm,get-dynamic-sensor-state
+ * RTAS Calls.
+ */
+static struct rtas_work_area *
+papr_dynamic_indice_buf_from_user(struct papr_indices_io_block __user *ubuf,
+				struct papr_indices_io_block *kbuf)
+{
+	struct rtas_work_area *work_area;
+	u32 length;
+	__be32 len_be;
+
+	if (copy_from_user(kbuf, ubuf, sizeof(*kbuf)))
+		return ERR_PTR(-EFAULT);
+
+
+	if (!string_is_terminated(kbuf->dynamic_param.location_code_str,
+			ARRAY_SIZE(kbuf->dynamic_param.location_code_str)))
+		return ERR_PTR(-EINVAL);
+
+	/*
+	 * The input data in the work area should be as follows:
+	 * - 32-bit integer length of the location code string,
+	 *   including NULL.
+	 * - Location code string, NULL terminated, identifying the
+	 *   token (sensor or indicator).
+	 * PAPR 2.13 - R1–7.3.18–5 ibm,set-dynamic-indicator
+	 *           - R1–7.3.19–5 ibm,get-dynamic-sensor-state
+	 */
+	/*
+	 * Length that user space passed should also include NULL
+	 * terminator.
+	 */
+	length = strlen(kbuf->dynamic_param.location_code_str) + 1;
+	if (length > LOC_CODE_SIZE)
+		return ERR_PTR(-EINVAL);
+
+	len_be = cpu_to_be32(length);
+
+	work_area = rtas_work_area_alloc(LOC_CODE_SIZE + sizeof(u32));
+	memcpy(rtas_work_area_raw_buf(work_area), &len_be, sizeof(u32));
+	memcpy((rtas_work_area_raw_buf(work_area) + sizeof(u32)),
+			&kbuf->dynamic_param.location_code_str, length);
+
+	return work_area;
+}
+
+/**
+ * papr_dynamic_indicator_ioc_set - ibm,set-dynamic-indicator RTAS Call
+ * PAPR 2.13 7.3.18
+ *
+ * @ubuf: Input parameters to RTAS call such as indicator token and
+ *        new state.
+ *
+ * Returns success or -errno.
+ */
+static long papr_dynamic_indicator_ioc_set(struct papr_indices_io_block __user *ubuf)
+{
+	struct papr_indices_io_block kbuf;
+	struct rtas_work_area *work_area;
+	s32 fwrc, token, ret;
+
+	token = rtas_token("ibm,set-dynamic-indicator");
+	if (token == RTAS_UNKNOWN_SERVICE)
+		return -ENOENT;
+
+	mutex_lock(&rtas_ibm_set_dynamic_indicator_lock);
+	work_area = papr_dynamic_indice_buf_from_user(ubuf, &kbuf);
+	if (IS_ERR(work_area)) {
+		ret = PTR_ERR(work_area);
+		goto out;
+	}
+
+	do {
+		fwrc = rtas_call(token, 3, 1, NULL,
+				kbuf.dynamic_param.token,
+				kbuf.dynamic_param.state,
+				rtas_work_area_phys(work_area));
+	} while (rtas_busy_delay(fwrc));
+
+	rtas_work_area_free(work_area);
+
+	switch (fwrc) {
+	case 0:		/* Success */
+		ret = 0;
+		break;
+	case RTAS_IBM_DYNAMIC_INDICE_NO_INDICATOR:	/* No such indicator */
+		ret = -EOPNOTSUPP;
+		break;
+	default:
+		pr_err("unexpected ibm,set-dynamic-indicator result %d\n",
+			fwrc);
+		fallthrough;
+	case RTAS_HARDWARE_ERROR:	/* Hardware/platform error */
+		ret = -EIO;
+		break;
+	}
+
+out:
+	mutex_unlock(&rtas_ibm_set_dynamic_indicator_lock);
+	return ret;
+}
+
 /*
  * Top-level ioctl handler for /dev/papr-indices.
  */
@@ -273,6 +384,12 @@ static long papr_indices_dev_ioctl(struct file *filp, unsigned int ioctl,
 	case PAPR_INDICES_IOC_GET:
 		ret = papr_indices_create_handle(argp);
 		break;
+	case PAPR_DYNAMIC_INDICATOR_IOC_SET:
+		if (filp->f_mode & FMODE_WRITE)
+			ret = papr_dynamic_indicator_ioc_set(argp);
+		else
+			ret = -EBADF;
+		break;
 	default:
 		ret = -ENOIOCTLCMD;
 		break;
@@ -296,6 +413,9 @@ static __init int papr_indices_init(void)
 	if (!rtas_service_present("ibm,get-indices"))
                 return -ENODEV;
 
+	if (!rtas_service_present("ibm,set-dynamic-indicator"))
+		return -ENODEV;
+
 	return misc_register(&papr_indices_dev);
 }
 machine_device_initcall(pseries, papr_indices_init);