[PATCH 0/6] Add character devices for indices and platform-dump RTAS

[PATCH 0/6] Add character devices for indices and platform-dump RTAS

[Haren Myneni]

Several APIs such as rtas_get_indices(), rtas_get_dynamic_sensor(),
rtas_set_dynamic_indicator() and rtas_platform_dump() provided by
librtas library are implemented in user space using rtas syscall
in combination with writable mappings of /dev/mem. But this
implementation is not compatible with system lockdown which
prohibits /dev/mem access. The current kernel already provides
char based driver interfaces for several RTAS calls such as VPD
and system parameters to support lockdown feature. 

This patch series adds new char based drivers, /dev/papr-indices
for ibm,get-indices, ibm,get-dynamic-sensor-state and
ibm,set-dynamic-indicator RTAS Calls. and /dev/papr-platform-dump
for ibm,platform-dump. Providing the similar open/ioctl/read
interfaces to the user space as in the case of VPD and system
parameters. 

I have made changes to librtas library to use the new kernel
interfaces if the corresponding device entry is available. 

This patch series has the following patches:
powerpc/pseries: Define common functions for RTAS sequence HCALLs
- For some of sequence based RTAS calls, the OS should not start
  another sequence with different input until the previous sequence
  is completed. So the sequence should be completed during ioctl()
  and expose the entire buffer during read(). ibm,get-indices is
  sequence based RTAS function similar to ibm,get-vpd and we already
  have the corresponding implementation for VPD driver. So update
  papr_rtas_sequence struct for RTAS call specific functions and move
  the top level sequence functions in to a separate file.

powerpc/pseries: Define papr_indices_io_block for papr-indices ioctls
- /dev/papr-indices driver supports ibm,get-indices,
  ibm,get-dynamic-sensor-state and ibm,set-dynamic-indicator RTAS Calls.
  papr-indices.h introduces 3 different ioctls for these RTAS calls and
  the corresponding ioctl input buffer.

powerpc/pseries: Add papr-indices char driver for ibm,get-indices HCALL
- Introduce /dev/papr-indices char based driver and add support for
  get-indices RTAS function

powerpc/pseries: Add ibm,set-dynamic-indicator RTAS call support
- Update /dev/papr-indices for set-dynamic-indicator RTAS function

powerpc/pseries: Add ibm,get-dynamic-sensor-state RTAS call support
-  Update /dev/papr-indices for  get-dynamic-sensor-state RTAS function

powerpc/pseries: Add papr-platform-dump character driver for dump
   retrieval
- Introduce /dev/papr-platform-dump char driver and adds support for
  ibm,platform-dump. Received suggestions from the previous post as a
  separate patch - Updated the patch with invalidating the dump using
  a separate ioctl. 

Haren Myneni (6):
  powerpc/pseries: Define common functions for RTAS sequence HCALLs
  powerpc/pseries: Define papr_indices_io_block for papr-indices ioctls
  powerpc/pseries: Add papr-indices char driver for ibm,get-indices
    HCALL
  powerpc/pseries: Add ibm,set-dynamic-indicator RTAS call support
  powerpc/pseries: Add ibm,get-dynamic-sensor-state RTAS call support
  powerpc/pseries: Add papr-platform-dump character driver for dump
    retrieval

 arch/powerpc/include/asm/rtas.h               |   3 +
 arch/powerpc/include/uapi/asm/papr-indices.h  |  41 ++
 .../include/uapi/asm/papr-platform-dump.h     |  15 +
 arch/powerpc/kernel/rtas.c                    |   6 +-
 arch/powerpc/platforms/pseries/Makefile       |   3 +-
 arch/powerpc/platforms/pseries/papr-indices.c | 552 ++++++++++++++++++
 .../platforms/pseries/papr-platform-dump.c    | 408 +++++++++++++
 .../platforms/pseries/papr-rtas-common.c      | 243 ++++++++
 .../platforms/pseries/papr-rtas-common.h      |  45 ++
 arch/powerpc/platforms/pseries/papr-vpd.c     | 266 ++-------
 10 files changed, 1356 insertions(+), 226 deletions(-)
 create mode 100644 arch/powerpc/include/uapi/asm/papr-indices.h
 create mode 100644 arch/powerpc/include/uapi/asm/papr-platform-dump.h
 create mode 100644 arch/powerpc/platforms/pseries/papr-indices.c
 create mode 100644 arch/powerpc/platforms/pseries/papr-platform-dump.c
 create mode 100644 arch/powerpc/platforms/pseries/papr-rtas-common.c
 create mode 100644 arch/powerpc/platforms/pseries/papr-rtas-common.h

-- 
2.43.5

[PATCH 1/6] powerpc/pseries: Define common functions for RTAS sequence HCALLs

[Haren Myneni]

The RTAS call can be normal where retrieves the data form the
hypervisor with one HCALL or sequence based HCALL which has to
issue multiple times until the complete data is obtained. For
some of these sequence HCALLs, the OS should not interleave
calls with different input until the sequence is completed.
The data is collected for each HCALL and copy to the buffer
for the entire sequence during ioctl() handle and then expose
this buffer to the user space with read() handle.

One such sequence RTAS call is ibm,get-vpd and its support is
already included in the current code. To add the similar support
for other sequence HCALLs, move the common functions in to
separate file and update papr_rtas_sequence struct with the
following callbacks so that HCALL specific code will  be defined
and executed to complete the sequence.

struct papr_rtas_sequence {
        int error;
        void params;
        void (*begin) (struct papr_rtas_sequence *, void *);
        void (*end) (struct papr_rtas_sequence *);
        const char * (*work) (struct papr_rtas_sequence *, size_t *);
};

params: Input parameters used to pass for HCALL.
Begin:	HCALL specific function to initialize data including
	work area allocation.
End:	HCALL specific function to free up resources (free
	work area) after the sequence is completed.
Work:	The actual HCALL specific function which collects the
	data from the hypervisor.

Signed-off-by: Haren Myneni <haren@linux.ibm.com>
---
 arch/powerpc/platforms/pseries/Makefile       |   2 +-
 .../platforms/pseries/papr-rtas-common.c      | 243 ++++++++++++++++
 .../platforms/pseries/papr-rtas-common.h      |  45 +++
 arch/powerpc/platforms/pseries/papr-vpd.c     | 266 +++---------------
 4 files changed, 333 insertions(+), 223 deletions(-)
 create mode 100644 arch/powerpc/platforms/pseries/papr-rtas-common.c
 create mode 100644 arch/powerpc/platforms/pseries/papr-rtas-common.h

diff --git a/arch/powerpc/platforms/pseries/Makefile b/arch/powerpc/platforms/pseries/Makefile
index 7bf506f6b8c8..697c216b70dc 100644
--- a/arch/powerpc/platforms/pseries/Makefile
+++ b/arch/powerpc/platforms/pseries/Makefile
@@ -3,7 +3,7 @@ ccflags-$(CONFIG_PPC_PSERIES_DEBUG)	+= -DDEBUG
 
 obj-y			:= lpar.o hvCall.o nvram.o reconfig.o \
 			   of_helpers.o rtas-work-area.o papr-sysparm.o \
-			   papr-vpd.o \
+			   papr-rtas-common.o papr-vpd.o \
 			   setup.o iommu.o event_sources.o ras.o \
 			   firmware.o power.o dlpar.o mobility.o rng.o \
 			   pci.o pci_dlpar.o eeh_pseries.o msi.o \
diff --git a/arch/powerpc/platforms/pseries/papr-rtas-common.c b/arch/powerpc/platforms/pseries/papr-rtas-common.c
new file mode 100644
index 000000000000..0209ec09d1fd
--- /dev/null
+++ b/arch/powerpc/platforms/pseries/papr-rtas-common.c
@@ -0,0 +1,243 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#define pr_fmt(fmt) "papr-common: " fmt
+
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/signal.h>
+#include <linux/slab.h>
+#include <linux/file.h>
+#include <linux/fs.h>
+#include <linux/anon_inodes.h>
+#include <linux/sched/signal.h>
+#include "papr-rtas-common.h"
+
+/*
+ * Sequence based RTAS HCALL has to issue multiple times to retrieve
+ * complete data from the hypervisor. For some of these RTAS calls,
+ * the OS should not interleave calls with different input until the
+ * sequence is completed. So data is collected for these calls during
+ * ioctl handle and export to user space with read() handle.
+ * This file provides common functions needed for such sequence based
+ * RTAS calls Ex: ibm,get-vpd and ibm,get-indices.
+ */
+
+bool papr_rtas_blob_has_data(const struct papr_rtas_blob *blob)
+{
+	return blob->data && blob->len;
+}
+
+void papr_rtas_blob_free(const struct papr_rtas_blob *blob)
+{
+	if (blob) {
+		kvfree(blob->data);
+		kfree(blob);
+	}
+}
+
+/**
+ * papr_rtas_blob_extend() - Append data to a &struct papr_rtas_blob.
+ * @blob: The blob to extend.
+ * @data: The new data to append to @blob.
+ * @len:  The length of @data.
+ *
+ * Context: May sleep.
+ * Return: -ENOMEM on allocation failure, 0 otherwise.
+ */
+static int papr_rtas_blob_extend(struct papr_rtas_blob *blob,
+				const char *data, size_t len)
+{
+	const size_t new_len = blob->len + len;
+	const size_t old_len = blob->len;
+	const char *old_ptr = blob->data;
+	char *new_ptr;
+
+	new_ptr = kvrealloc(old_ptr, new_len, GFP_KERNEL_ACCOUNT);
+	if (!new_ptr)
+		return -ENOMEM;
+
+	memcpy(&new_ptr[old_len], data, len);
+	blob->data = new_ptr;
+	blob->len = new_len;
+	return 0;
+}
+
+/**
+ * papr_rtas_blob_generate() - Construct a new &struct papr_rtas_blob.
+ * @seq: work function of the caller that is called to obtain
+ *       data with the caller RTAS call.
+ *
+ * The @work callback is invoked until it returns NULL. @seq is
+ * passed to @work in its first argument on each call. When
+ * @work returns data, it should store the data length in its
+ * second argument.
+ *
+ * Context: May sleep.
+ * Return: A completely populated &struct papr_rtas_blob, or NULL on error.
+ */
+static const struct papr_rtas_blob *
+papr_rtas_blob_generate(struct papr_rtas_sequence *seq)
+{
+	struct papr_rtas_blob *blob;
+	const char *buf;
+	size_t len;
+	int err = 0;
+
+	blob  = kzalloc(sizeof(*blob), GFP_KERNEL_ACCOUNT);
+	if (!blob)
+		return NULL;
+
+	if (!seq->work)
+		return ERR_PTR(-EINVAL);
+
+
+	while (err == 0 && (buf = seq->work(seq, &len)))
+		err = papr_rtas_blob_extend(blob, buf, len);
+
+	if (err != 0 || !papr_rtas_blob_has_data(blob))
+		goto free_blob;
+
+	return blob;
+free_blob:
+	papr_rtas_blob_free(blob);
+	return NULL;
+}
+
+int papr_rtas_sequence_set_err(struct papr_rtas_sequence *seq, int err)
+{
+	/* Preserve the first error recorded. */
+	if (seq->error == 0)
+		seq->error = err;
+
+	return seq->error;
+}
+
+/*
+ * Higher-level retrieval code below. These functions use the
+ * papr_rtas_blob_* and sequence_* APIs defined above to create fd-based
+ * handles for consumption by user space.
+ */
+
+/**
+ * papr_rtas_run_sequence() - Run a single retrieval sequence.
+ * @seq:	Functions of the caller to complete the sequence
+ * @param:	Inputs to the caller's RTAS call
+ *
+ * Context: May sleep. Holds a mutex and an RTAS work area for its
+ *          duration. Typically performs multiple sleepable slab
+ *          allocations.
+ *
+ * Return: A populated &struct papr_rtas_blob on success. Encoded error
+ * pointer otherwise.
+ */
+static const struct papr_rtas_blob *papr_rtas_run_sequence(struct papr_rtas_sequence *seq,
+							void *param)
+{
+	const struct papr_rtas_blob *blob;
+
+	if (seq->begin)
+		seq->begin(seq, param);
+
+	blob = papr_rtas_blob_generate(seq);
+	if (!blob)
+		papr_rtas_sequence_set_err(seq, -ENOMEM);
+
+	if (seq->end)
+		seq->end(seq);
+
+
+	if (seq->error) {
+		papr_rtas_blob_free(blob);
+		return ERR_PTR(seq->error);
+	}
+
+	return blob;
+}
+
+/**
+ * papr_rtas_retrieve() - Return the data blob that is exposed to
+ * user space.
+ * @seq: RTAS call specific functions to be invoked until the
+ *       sequence is completed.
+ * @param: RTAS calls specific parameters.
+ *
+ * Run sequences against @param until a blob is successfully
+ * instantiated, or a hard error is encountered, or a fatal signal is
+ * pending.
+ *
+ * Context: May sleep.
+ * Return: A fully populated data blob when successful. Encoded error
+ * pointer otherwise.
+ */
+const struct papr_rtas_blob *papr_rtas_retrieve(struct papr_rtas_sequence *seq,
+						void *param)
+{
+	const struct papr_rtas_blob *blob;
+
+	/*
+	 * EAGAIN means the sequence returns error with a -4 (data
+	 * changed and need to start the sequence) status from RTAS calls
+	 * and we should attempt a new sequence. PAPR+ (v2.13 R1–7.3.20–5
+	 * - ibm,get-vpd, R1–7.3.17–6 - ibm,get-indices) indicates that
+	 * this should be a transient condition, not something that
+	 * happens continuously. But we'll stop trying on a fatal signal.
+	 */
+	do {
+		blob = papr_rtas_run_sequence(seq, param);
+		if (!IS_ERR(blob)) /* Success. */
+			break;
+		if (PTR_ERR(blob) != -EAGAIN) /* Hard error. */
+			break;
+		cond_resched();
+	} while (!fatal_signal_pending(current));
+
+	return blob;
+}
+
+/**
+ * papr_rtas_setup_file_interface - Complete the sequence and obtain
+ * the data and export to user space with fd-based handles. Then the
+ * user spave gets the data with read() handle.
+ * @seq: RTAS call specific functions to get the data.
+ * @param: RTAS call specific input parameters.
+ * @fops: RTAS call specific file operations such as read().
+ * @name: RTAS call specific char device node.
+ *
+ * Return: FD handle for consumption by user space
+ */
+long papr_rtas_setup_file_interface(struct papr_rtas_sequence *seq,
+				void *param,
+				const struct file_operations *fops,
+				char *name)
+{
+	const struct papr_rtas_blob *blob;
+	struct file *file;
+	long ret;
+	int fd;
+
+	blob = papr_rtas_retrieve(seq, param);
+	if (IS_ERR(blob))
+		return PTR_ERR(blob);
+
+	fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC);
+	if (fd < 0) {
+		ret = fd;
+		goto free_blob;
+	}
+
+	file = anon_inode_getfile(name, fops, (void *)blob, O_RDONLY);
+	if (IS_ERR(file)) {
+		ret = PTR_ERR(file);
+		goto put_fd;
+	}
+
+	file->f_mode |= FMODE_LSEEK | FMODE_PREAD;
+	fd_install(fd, file);
+	return fd;
+
+put_fd:
+	put_unused_fd(fd);
+free_blob:
+	papr_rtas_blob_free(blob);
+	return ret;
+}
diff --git a/arch/powerpc/platforms/pseries/papr-rtas-common.h b/arch/powerpc/platforms/pseries/papr-rtas-common.h
new file mode 100644
index 000000000000..54e9686da04b
--- /dev/null
+++ b/arch/powerpc/platforms/pseries/papr-rtas-common.h
@@ -0,0 +1,45 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef _ASM_POWERPC_PAPR_RTAS_COMMON_H
+#define _ASM_POWERPC_PAPR_RTAS_COMMON_H
+
+#include <linux/types.h>
+
+/*
+ * Internal "blob" APIs for accumulating RTAS call results into
+ * an immutable buffer to be attached to a file descriptor.
+ */
+struct papr_rtas_blob {
+	const char *data;
+	size_t len;
+};
+
+/**
+ * struct papr_sequence - State for managing a sequence of RTAS calls.
+ * @error:  Shall be zero as long as the sequence has not encountered an error,
+ *          -ve errno otherwise. Use papr_rtas_sequence_set_err() to update.
+ * @params: Parameter block to pass to rtas_*() calls.
+ * @begin: Work area allocation and initialize the needed parameter
+ *         values passed to RTAS call
+ * @end: Free the allocated work area
+ * @work: Obtain data with RTAS call and invoke it until the sequence is
+ *        completed.
+ *
+ */
+struct papr_rtas_sequence {
+	int error;
+	void *params;
+	void (*begin)(struct papr_rtas_sequence *seq, void *param);
+	void (*end)(struct papr_rtas_sequence *seq);
+	const char *(*work)(struct papr_rtas_sequence *seq, size_t *len);
+};
+
+extern bool papr_rtas_blob_has_data(const struct papr_rtas_blob *blob);
+extern void papr_rtas_blob_free(const struct papr_rtas_blob *blob);
+extern int papr_rtas_sequence_set_err(struct papr_rtas_sequence *seq,
+		int err);
+extern const struct papr_rtas_blob *papr_rtas_retrieve(struct papr_rtas_sequence *seq, void *param);
+extern long papr_rtas_setup_file_interface(struct papr_rtas_sequence *seq,
+		void *param, const struct file_operations *fops, char *name);
+
+#endif /* _ASM_POWERPC_PAPR_RTAS_COMMON_H */
+
diff --git a/arch/powerpc/platforms/pseries/papr-vpd.c b/arch/powerpc/platforms/pseries/papr-vpd.c
index 1574176e3ffc..13dd9511d035 100644
--- a/arch/powerpc/platforms/pseries/papr-vpd.c
+++ b/arch/powerpc/platforms/pseries/papr-vpd.c
@@ -2,7 +2,6 @@
 
 #define pr_fmt(fmt) "papr-vpd: " fmt
 
-#include <linux/anon_inodes.h>
 #include <linux/build_bug.h>
 #include <linux/file.h>
 #include <linux/fs.h>
@@ -20,6 +19,7 @@
 #include <asm/rtas-work-area.h>
 #include <asm/rtas.h>
 #include <uapi/asm/papr-vpd.h>
+#include "papr-rtas-common.h"
 
 /*
  * Function-specific return values for ibm,get-vpd, derived from PAPR+
@@ -93,6 +93,7 @@ static int rtas_ibm_get_vpd(struct rtas_ibm_get_vpd_params *params)
 		break;
 	case RTAS_IBM_GET_VPD_START_OVER:
 		ret = -EAGAIN;
+		pr_info_ratelimited("VPD changed during retrieval, retrying\n");
 		break;
 	case RTAS_IBM_GET_VPD_MORE_DATA:
 		params->sequence = rets[0];
@@ -118,91 +119,6 @@ static int rtas_ibm_get_vpd(struct rtas_ibm_get_vpd_params *params)
 	return ret;
 }
 
-/*
- * Internal VPD "blob" APIs for accumulating ibm,get-vpd results into
- * an immutable buffer to be attached to a file descriptor.
- */
-struct vpd_blob {
-	const char *data;
-	size_t len;
-};
-
-static bool vpd_blob_has_data(const struct vpd_blob *blob)
-{
-	return blob->data && blob->len;
-}
-
-static void vpd_blob_free(const struct vpd_blob *blob)
-{
-	if (blob) {
-		kvfree(blob->data);
-		kfree(blob);
-	}
-}
-
-/**
- * vpd_blob_extend() - Append data to a &struct vpd_blob.
- * @blob: The blob to extend.
- * @data: The new data to append to @blob.
- * @len:  The length of @data.
- *
- * Context: May sleep.
- * Return: -ENOMEM on allocation failure, 0 otherwise.
- */
-static int vpd_blob_extend(struct vpd_blob *blob, const char *data, size_t len)
-{
-	const size_t new_len = blob->len + len;
-	const size_t old_len = blob->len;
-	const char *old_ptr = blob->data;
-	char *new_ptr;
-
-	new_ptr = kvrealloc(old_ptr, new_len, GFP_KERNEL_ACCOUNT);
-	if (!new_ptr)
-		return -ENOMEM;
-
-	memcpy(&new_ptr[old_len], data, len);
-	blob->data = new_ptr;
-	blob->len = new_len;
-	return 0;
-}
-
-/**
- * vpd_blob_generate() - Construct a new &struct vpd_blob.
- * @generator: Function that supplies the blob data.
- * @arg:       Context pointer supplied by caller, passed to @generator.
- *
- * The @generator callback is invoked until it returns NULL. @arg is
- * passed to @generator in its first argument on each call. When
- * @generator returns data, it should store the data length in its
- * second argument.
- *
- * Context: May sleep.
- * Return: A completely populated &struct vpd_blob, or NULL on error.
- */
-static const struct vpd_blob *
-vpd_blob_generate(const char * (*generator)(void *, size_t *), void *arg)
-{
-	struct vpd_blob *blob;
-	const char *buf;
-	size_t len;
-	int err = 0;
-
-	blob  = kzalloc(sizeof(*blob), GFP_KERNEL_ACCOUNT);
-	if (!blob)
-		return NULL;
-
-	while (err == 0 && (buf = generator(arg, &len)))
-		err = vpd_blob_extend(blob, buf, len);
-
-	if (err != 0 || !vpd_blob_has_data(blob))
-		goto free_blob;
-
-	return blob;
-free_blob:
-	vpd_blob_free(blob);
-	return NULL;
-}
-
 /*
  * Internal VPD sequence APIs. A VPD sequence is a series of calls to
  * ibm,get-vpd for a given location code. The sequence ends when an
@@ -210,17 +126,6 @@ vpd_blob_generate(const char * (*generator)(void *, size_t *), void *arg)
  * returned.
  */
 
-/**
- * struct vpd_sequence - State for managing a VPD sequence.
- * @error:  Shall be zero as long as the sequence has not encountered an error,
- *          -ve errno otherwise. Use vpd_sequence_set_err() to update this.
- * @params: Parameter block to pass to rtas_ibm_get_vpd().
- */
-struct vpd_sequence {
-	int error;
-	struct rtas_ibm_get_vpd_params params;
-};
-
 /**
  * vpd_sequence_begin() - Begin a VPD retrieval sequence.
  * @seq:      Uninitialized sequence state.
@@ -232,9 +137,9 @@ struct vpd_sequence {
  *
  * Context: May sleep.
  */
-static void vpd_sequence_begin(struct vpd_sequence *seq,
-			       const struct papr_location_code *loc_code)
+static void vpd_sequence_begin(struct papr_rtas_sequence *seq, void *param)
 {
+	struct rtas_ibm_get_vpd_params *vpd_params;
 	/*
 	 * Use a static data structure for the location code passed to
 	 * RTAS to ensure it's in the RMA and avoid a separate work
@@ -249,14 +154,12 @@ static void vpd_sequence_begin(struct vpd_sequence *seq,
 	 * allocate the work area under the lock.
 	 */
 	mutex_lock(&rtas_ibm_get_vpd_lock);
-	static_loc_code = *loc_code;
-	*seq = (struct vpd_sequence) {
-		.params = {
-			.work_area = rtas_work_area_alloc(SZ_4K),
-			.loc_code = &static_loc_code,
-			.sequence = 1,
-		},
-	};
+	static_loc_code = *(struct papr_location_code *)param;
+	vpd_params =  (struct rtas_ibm_get_vpd_params *)seq->params;
+	vpd_params->work_area = rtas_work_area_alloc(SZ_4K);
+	vpd_params->loc_code = &static_loc_code;
+	vpd_params->sequence = 1;
+	vpd_params->status = 0;
 }
 
 /**
@@ -265,9 +168,12 @@ static void vpd_sequence_begin(struct vpd_sequence *seq,
  *
  * Releases resources obtained by vpd_sequence_begin().
  */
-static void vpd_sequence_end(struct vpd_sequence *seq)
+static void vpd_sequence_end(struct papr_rtas_sequence *seq)
 {
-	rtas_work_area_free(seq->params.work_area);
+	struct rtas_ibm_get_vpd_params *vpd_params;
+
+	vpd_params =  (struct rtas_ibm_get_vpd_params *)seq->params;
+	rtas_work_area_free(vpd_params->work_area);
 	mutex_unlock(&rtas_ibm_get_vpd_lock);
 }
 
@@ -283,16 +189,19 @@ static void vpd_sequence_end(struct vpd_sequence *seq)
  * Return: True if the sequence has encountered an error or if all VPD for
  *         this sequence has been retrieved. False otherwise.
  */
-static bool vpd_sequence_should_stop(const struct vpd_sequence *seq)
+static bool vpd_sequence_should_stop(const struct papr_rtas_sequence *seq)
 {
+	struct rtas_ibm_get_vpd_params *vpd_params;
 	bool done;
 
 	if (seq->error)
 		return true;
 
-	switch (seq->params.status) {
+	vpd_params =  (struct rtas_ibm_get_vpd_params *)seq->params;
+
+	switch (vpd_params->status) {
 	case 0:
-		if (seq->params.written == 0)
+		if (vpd_params->written == 0)
 			done = false; /* Initial state. */
 		else
 			done = true; /* All data consumed. */
@@ -308,26 +217,19 @@ static bool vpd_sequence_should_stop(const struct vpd_sequence *seq)
 	return done;
 }
 
-static int vpd_sequence_set_err(struct vpd_sequence *seq, int err)
-{
-	/* Preserve the first error recorded. */
-	if (seq->error == 0)
-		seq->error = err;
-
-	return seq->error;
-}
-
 /*
- * Generator function to be passed to vpd_blob_generate().
+ * Generator function to be passed to papr_rtas_blob_generate().
  */
-static const char *vpd_sequence_fill_work_area(void *arg, size_t *len)
+static const char *vpd_sequence_fill_work_area(struct papr_rtas_sequence *seq,
+						size_t *len)
 {
-	struct vpd_sequence *seq = arg;
-	struct rtas_ibm_get_vpd_params *p = &seq->params;
+	struct rtas_ibm_get_vpd_params *p;
+
+	p = (struct rtas_ibm_get_vpd_params *)seq->params;
 
 	if (vpd_sequence_should_stop(seq))
 		return NULL;
-	if (vpd_sequence_set_err(seq, rtas_ibm_get_vpd(p)))
+	if (papr_rtas_sequence_set_err(seq, rtas_ibm_get_vpd(p)))
 		return NULL;
 	*len = p->written;
 	return rtas_work_area_raw_buf(p->work_area);
@@ -335,82 +237,16 @@ static const char *vpd_sequence_fill_work_area(void *arg, size_t *len)
 
 /*
  * Higher-level VPD retrieval code below. These functions use the
- * vpd_blob_* and vpd_sequence_* APIs defined above to create fd-based
+ * papr_rtas_blob_* and vpd_sequence_* APIs defined above to create fd-based
  * VPD handles for consumption by user space.
  */
 
-/**
- * papr_vpd_run_sequence() - Run a single VPD retrieval sequence.
- * @loc_code: Location code that defines the scope of VPD to return.
- *
- * Context: May sleep. Holds a mutex and an RTAS work area for its
- *          duration. Typically performs multiple sleepable slab
- *          allocations.
- *
- * Return: A populated &struct vpd_blob on success. Encoded error
- * pointer otherwise.
- */
-static const struct vpd_blob *papr_vpd_run_sequence(const struct papr_location_code *loc_code)
-{
-	const struct vpd_blob *blob;
-	struct vpd_sequence seq;
-
-	vpd_sequence_begin(&seq, loc_code);
-	blob = vpd_blob_generate(vpd_sequence_fill_work_area, &seq);
-	if (!blob)
-		vpd_sequence_set_err(&seq, -ENOMEM);
-	vpd_sequence_end(&seq);
-
-	if (seq.error) {
-		vpd_blob_free(blob);
-		return ERR_PTR(seq.error);
-	}
-
-	return blob;
-}
-
-/**
- * papr_vpd_retrieve() - Return the VPD for a location code.
- * @loc_code: Location code that defines the scope of VPD to return.
- *
- * Run VPD sequences against @loc_code until a blob is successfully
- * instantiated, or a hard error is encountered, or a fatal signal is
- * pending.
- *
- * Context: May sleep.
- * Return: A fully populated VPD blob when successful. Encoded error
- * pointer otherwise.
- */
-static const struct vpd_blob *papr_vpd_retrieve(const struct papr_location_code *loc_code)
-{
-	const struct vpd_blob *blob;
-
-	/*
-	 * EAGAIN means the sequence errored with a -4 (VPD changed)
-	 * status from ibm,get-vpd, and we should attempt a new
-	 * sequence. PAPR+ v2.13 R1–7.3.20–5 indicates that this
-	 * should be a transient condition, not something that happens
-	 * continuously. But we'll stop trying on a fatal signal.
-	 */
-	do {
-		blob = papr_vpd_run_sequence(loc_code);
-		if (!IS_ERR(blob)) /* Success. */
-			break;
-		if (PTR_ERR(blob) != -EAGAIN) /* Hard error. */
-			break;
-		pr_info_ratelimited("VPD changed during retrieval, retrying\n");
-		cond_resched();
-	} while (!fatal_signal_pending(current));
-
-	return blob;
-}
-
 static ssize_t papr_vpd_handle_read(struct file *file, char __user *buf, size_t size, loff_t *off)
 {
-	const struct vpd_blob *blob = file->private_data;
+	const struct papr_rtas_blob *blob = file->private_data;
 
 	/* bug: we should not instantiate a handle without any data attached. */
-	if (!vpd_blob_has_data(blob)) {
+	if (!papr_rtas_blob_has_data(blob)) {
 		pr_err_once("handle without data\n");
 		return -EIO;
 	}
@@ -420,16 +256,16 @@ static ssize_t papr_vpd_handle_read(struct file *file, char __user *buf, size_t
 
 static int papr_vpd_handle_release(struct inode *inode, struct file *file)
 {
-	const struct vpd_blob *blob = file->private_data;
+	const struct papr_rtas_blob *blob = file->private_data;
 
-	vpd_blob_free(blob);
+	papr_rtas_blob_free(blob);
 
 	return 0;
 }
 
 static loff_t papr_vpd_handle_seek(struct file *file, loff_t off, int whence)
 {
-	const struct vpd_blob *blob = file->private_data;
+	const struct papr_rtas_blob *blob = file->private_data;
 
 	return fixed_size_llseek(file, off, whence, blob->len);
 }
@@ -460,10 +296,9 @@ static const struct file_operations papr_vpd_handle_ops = {
  */
 static long papr_vpd_create_handle(struct papr_location_code __user *ulc)
 {
+	struct rtas_ibm_get_vpd_params vpd_params = {};
+	struct papr_rtas_sequence seq = {};
 	struct papr_location_code klc;
-	const struct vpd_blob *blob;
-	struct file *file;
-	long err;
 	int fd;
 
 	if (copy_from_user(&klc, ulc, sizeof(klc)))
@@ -472,31 +307,18 @@ static long papr_vpd_create_handle(struct papr_location_code __user *ulc)
 	if (!string_is_terminated(klc.str, ARRAY_SIZE(klc.str)))
 		return -EINVAL;
 
-	blob = papr_vpd_retrieve(&klc);
-	if (IS_ERR(blob))
-		return PTR_ERR(blob);
+	seq = (struct papr_rtas_sequence) {
+		.begin = vpd_sequence_begin,
+		.end = vpd_sequence_end,
+		.work = vpd_sequence_fill_work_area,
+	};
 
-	fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC);
-	if (fd < 0) {
-		err = fd;
-		goto free_blob;
-	}
+	seq.params = (void *)&vpd_params;
 
-	file = anon_inode_getfile("[papr-vpd]", &papr_vpd_handle_ops,
-				  (void *)blob, O_RDONLY);
-	if (IS_ERR(file)) {
-		err = PTR_ERR(file);
-		goto put_fd;
-	}
+	fd = papr_rtas_setup_file_interface(&seq, &klc,
+			&papr_vpd_handle_ops, "[papr-vpd]");
 
-	file->f_mode |= FMODE_LSEEK | FMODE_PREAD;
-	fd_install(fd, file);
 	return fd;
-put_fd:
-	put_unused_fd(fd);
-free_blob:
-	vpd_blob_free(blob);
-	return err;
 }
 
 /*
-- 
2.43.5

[PATCH 2/6] powerpc/pseries: Define papr_indices_io_block for papr-indices ioctls

[Haren Myneni]

To issue ibm,get-indices, ibm,set-dynamic-indicator and
ibm,get-dynamic-sensor-state in the user space, the RMO buffer is
allocated for the work area which is restricted under system
lockdown. So instead of user space execution, the kernel will
provide /dev/papr-indices interface to execute these RTAS HCALLs.

The user space assigns data in papr_indices_io_block struct
depends on the specific HCALL and passes to the following ioctls:

PAPR_INDICES_IOC_GET:		Use for ibm,get-indices. Returns a
				get-indices handle fd to read data.
PAPR_DYNAMIC_SENSOR_IOC_GET:	Use for  ibm,get-dynamic-sensor-state.
				Updates the sensor state in
				papr_indices_io_block.dynamic_param.state

PAPR_DYNAMIC_INDICATOR_IOC_SET:	Use for ibm,set-dynamic-indicator.
				Sets the new state for the input
				indicator.

Signed-off-by: Haren Myneni <haren@linux.ibm.com>
---
 arch/powerpc/include/uapi/asm/papr-indices.h | 41 ++++++++++++++++++++
 1 file changed, 41 insertions(+)
 create mode 100644 arch/powerpc/include/uapi/asm/papr-indices.h

diff --git a/arch/powerpc/include/uapi/asm/papr-indices.h b/arch/powerpc/include/uapi/asm/papr-indices.h
new file mode 100644
index 000000000000..c580025fe201
--- /dev/null
+++ b/arch/powerpc/include/uapi/asm/papr-indices.h
@@ -0,0 +1,41 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+#ifndef _UAPI_PAPR_INDICES_H_
+#define _UAPI_PAPR_INDICES_H_
+
+#include <linux/types.h>
+#include <asm/ioctl.h>
+#include <asm/papr-miscdev.h>
+
+#define LOC_CODE_SIZE			80
+#define RTAS_GET_INDICES_BUF_SIZE	SZ_4K
+
+struct papr_indices_io_block {
+	union {
+		struct {
+			__u8 is_sensor; /* 0 for indicator and 1 for sensor */
+			__u32 indice_type;
+		} indices;
+		struct {
+			__u32 token; /* Sensor or indicator token */
+			__u32 state; /* get / set state */
+			/*
+			 * PAPR+ 12.3.2.4 Converged Location Code Rules - Length
+			 * Restrictions. 79 characters plus null.
+			 */
+			char location_code_str[LOC_CODE_SIZE]; /* location code */
+		} dynamic_param;
+	};
+};
+
+/*
+ * ioctls for /dev/papr-indices.
+ * PAPR_INDICES_IOC_GET:	Returns a get-indices handle fd to read data
+ * PAPR_DYNAMIC_SENSOR_IOC_GET:	Gets the state of the input sensor
+ * PAPR_DYNAMIC_INDICATOR_IOC_SET: Sets the new state for the input indicator
+ */
+#define PAPR_INDICES_IOC_GET		_IOW(PAPR_MISCDEV_IOC_ID, 3, struct papr_indices_io_block)
+#define PAPR_DYNAMIC_SENSOR_IOC_GET	_IOWR(PAPR_MISCDEV_IOC_ID, 4, struct papr_indices_io_block)
+#define PAPR_DYNAMIC_INDICATOR_IOC_SET	_IOW(PAPR_MISCDEV_IOC_ID, 5, struct papr_indices_io_block)
+
+
+#endif /* _UAPI_PAPR_INDICES_H_ */
-- 
2.43.5

[PATCH 3/6] powerpc/pseries: Add papr-indices char driver for ibm,get-indices HCALL

[Haren Myneni]

The RTAS call ibm,get-indices is used to obtain indices and
location codes for a specified indicator or sensor token. The
current implementation uses rtas_get_indices() API provided by
librtas library which allocates RMO buffer and issue this RTAS
call in the user space. But writable mapping /dev/mem access by
the user space is prohibited under system lockdown.

To overcome the restricted access in the user space, the kernel
provide interfaces to collect indices data from the hypervisor.
This patch adds papr-indices character driver and expose standard
interfaces such as open / ioctl/ read to user space in ways that
are compatible with lockdown.

PAPR (2.13 7.3.17 ibm,get-indices RTAS Call) describes the
following steps to retrieve all indices data:
- User input parameters to the RTAS call: sensor or indicator,
  and indice type
- ibm,get-indices is sequence RTAS call which means has to issue
  multiple times to get the entire list of indicators or sensors
  of a particular type. The hypervisor expects the first RTAS call
  with the sequence 1 and the subsequent calls with the sequence
  number returned from the previous calls.
- The OS may not interleave calls to ibm,get-indices for different
  indicator or sensor types. Means other RTAS calls with different
  type should not be issued while the previous type sequence is in
  progress. So collect the entire list of indices and copied to
  buffer BLOB during ioctl() and expose this buffer to the user
  space with the file descriptor.
- The hypervisor fills the work area with a specific format but
  does not return the number of bytes written to the buffer.
  Instead of parsing the data for each call to determine the data
  length, copy the work area size (RTAS_GET_INDICES_BUF_SIZE) to
  the buffer. Return work-area size of data to the user space for
  each read() call.

Expose these interfaces to user space with a /dev/papr-indices
character device using the following programming model:

 int devfd = open("/dev/papr-indices", O_RDONLY);
 int fd = ioctl(devfd, PAPR_INDICES_IOC_GET,
		struct papr_indices_io_block)
  - Collect all indices data for the specified token to the buffer
 char *buf = malloc(RTAS_GET_INDICES_BUF_SIZE);
 length = read(fd, buf,  RTAS_GET_INDICES_BUF_SIZE)
  - RTAS_GET_INDICES_BUF_SIZE of data is returned to the user
    space.
  - The user space retrieves the indices and their location codes
    from the buffer
  - Should issue multiple read() calls until reaches the end of
    BLOB buffer.

The read() should use the file descriptor obtained from ioctl to
get the data that is exposed to file descriptor. Implemented
support in librtas (rtas_get_indices()) for this new ABI for
system lockdown.

Signed-off-by: Haren Myneni <haren@linux.ibm.com>
---
 arch/powerpc/include/asm/rtas.h               |   1 +
 arch/powerpc/kernel/rtas.c                    |   2 +-
 arch/powerpc/platforms/pseries/Makefile       |   2 +-
 arch/powerpc/platforms/pseries/papr-indices.c | 369 ++++++++++++++++++
 4 files changed, 372 insertions(+), 2 deletions(-)
 create mode 100644 arch/powerpc/platforms/pseries/papr-indices.c

diff --git a/arch/powerpc/include/asm/rtas.h b/arch/powerpc/include/asm/rtas.h
index 04406162fc5a..7dc527a5aaac 100644
--- a/arch/powerpc/include/asm/rtas.h
+++ b/arch/powerpc/include/asm/rtas.h
@@ -515,6 +515,7 @@ extern char rtas_data_buf[RTAS_DATA_BUF_SIZE];
 extern unsigned long rtas_rmo_buf;
 
 extern struct mutex rtas_ibm_get_vpd_lock;
+extern struct mutex rtas_ibm_get_indices_lock;
 
 #define GLOBAL_INTERRUPT_QUEUE 9005
 
diff --git a/arch/powerpc/kernel/rtas.c b/arch/powerpc/kernel/rtas.c
index d31c9799cab2..76c634b92cb2 100644
--- a/arch/powerpc/kernel/rtas.c
+++ b/arch/powerpc/kernel/rtas.c
@@ -93,11 +93,11 @@ struct rtas_function {
  */
 static DEFINE_MUTEX(rtas_ibm_activate_firmware_lock);
 static DEFINE_MUTEX(rtas_ibm_get_dynamic_sensor_state_lock);
-static DEFINE_MUTEX(rtas_ibm_get_indices_lock);
 static DEFINE_MUTEX(rtas_ibm_lpar_perftools_lock);
 static DEFINE_MUTEX(rtas_ibm_physical_attestation_lock);
 static DEFINE_MUTEX(rtas_ibm_set_dynamic_indicator_lock);
 DEFINE_MUTEX(rtas_ibm_get_vpd_lock);
+DEFINE_MUTEX(rtas_ibm_get_indices_lock);
 
 static struct rtas_function rtas_function_table[] __ro_after_init = {
 	[RTAS_FNIDX__CHECK_EXCEPTION] = {
diff --git a/arch/powerpc/platforms/pseries/Makefile b/arch/powerpc/platforms/pseries/Makefile
index 697c216b70dc..e1db61877bb9 100644
--- a/arch/powerpc/platforms/pseries/Makefile
+++ b/arch/powerpc/platforms/pseries/Makefile
@@ -3,7 +3,7 @@ ccflags-$(CONFIG_PPC_PSERIES_DEBUG)	+= -DDEBUG
 
 obj-y			:= lpar.o hvCall.o nvram.o reconfig.o \
 			   of_helpers.o rtas-work-area.o papr-sysparm.o \
-			   papr-rtas-common.o papr-vpd.o \
+			   papr-rtas-common.o papr-vpd.o papr-indices.o \
 			   setup.o iommu.o event_sources.o ras.o \
 			   firmware.o power.o dlpar.o mobility.o rng.o \
 			   pci.o pci_dlpar.o eeh_pseries.o msi.o \
diff --git a/arch/powerpc/platforms/pseries/papr-indices.c b/arch/powerpc/platforms/pseries/papr-indices.c
new file mode 100644
index 000000000000..d73aa329bd70
--- /dev/null
+++ b/arch/powerpc/platforms/pseries/papr-indices.c
@@ -0,0 +1,369 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#define pr_fmt(fmt) "papr-indices: " fmt
+
+#include <linux/build_bug.h>
+#include <linux/file.h>
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/lockdep.h>
+#include <linux/kernel.h>
+#include <linux/miscdevice.h>
+#include <linux/signal.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/string_helpers.h>
+#include <linux/uaccess.h>
+#include <asm/machdep.h>
+#include <asm/rtas-work-area.h>
+#include <asm/rtas.h>
+#include <uapi/asm/papr-indices.h>
+#include "papr-rtas-common.h"
+/*
+ * Function-specific return values for ibm,get-indices, derived from PAPR+
+ * v2.13 7.3.20 "ibm,get-indices RTAS Call".
+ */
+#define RTAS_IBM_GET_INDICES_COMPLETE    0 /* indices data has been retrieved. */
+#define RTAS_IBM_GET_INDICES_MORE_DATA   1 /* More data is available. */
+#define RTAS_IBM_GET_INDICES_START_OVER -4 /* Indices list changed, restart call sequence. */
+
+/**
+ * struct rtas_ibm_get_indices_params - Parameters (in and out) for
+ *                                      ibm,get-indices.
+ * @is_sensor:	In: Caller-provided whether sensor or indicator.
+ * @indice_type:In: Caller-provided indice (sensor or indicator) token
+ * @work_area:	In: Caller-provided work area buffer for results.
+ * @next:	In: Sequence number. Out: Next sequence number.
+ * @status:	Out: RTAS call status.
+ */
+struct rtas_get_indices_params {
+	u8 is_sensor;
+	u32 indice_type;
+	struct rtas_work_area *work_area;
+	u32 next;
+	s32 status;
+};
+
+/**
+ * rtas_ibm_get_indices() - Call ibm,get-indices to fill a work area buffer.
+ * @params: See &struct rtas_ibm_get_indices_params.
+ *
+ * Calls ibm,get-indices until it errors or successfully deposits data
+ * into the supplied work area. Handles RTAS retry statuses. Maps RTAS
+ * error statuses to reasonable errno values.
+ *
+ * The caller is expected to invoke rtas_ibm_get_indices() multiple times
+ * to retrieve all indices data for the provided indice type. Only one
+ * sequence should be in progress at any time; starting a new sequence
+ * will disrupt any sequence already in progress. Serialization of
+ * indices retrieval sequences is the responsibility of the caller.
+ *
+ * The caller should inspect @params.status to determine whether more
+ * calls are needed to complete the sequence.
+ *
+ * Context: May sleep.
+ * Return: -ve on error, 0 otherwise.
+ */
+static int rtas_ibm_get_indices(struct rtas_get_indices_params *params)
+{
+	struct rtas_work_area *work_area = params->work_area;
+	const s32 token = rtas_function_token(RTAS_FN_IBM_GET_INDICES);
+	u32 rets;
+	s32 fwrc;
+	int ret;
+
+	if (token == RTAS_UNKNOWN_SERVICE)
+		return -ENOENT;
+
+	lockdep_assert_held(&rtas_ibm_get_indices_lock);
+
+	do {
+		fwrc = rtas_call(token, 5, 2, &rets, params->is_sensor,
+				params->indice_type,
+				rtas_work_area_phys(work_area),
+				rtas_work_area_size(work_area),
+				params->next);
+	} while (rtas_busy_delay(fwrc));
+
+	switch (fwrc) {
+	case RTAS_HARDWARE_ERROR:
+		ret = -EIO;
+		break;
+	case RTAS_INVALID_PARAMETER: /* Indicator type is not supported */
+		ret = -EINVAL;
+		break;
+	case RTAS_IBM_GET_INDICES_START_OVER:
+		ret = -EAGAIN;
+		pr_info_ratelimited("Indices changed during retrieval, retrying\n");
+		params->next = 1;
+		break;
+	case RTAS_IBM_GET_INDICES_MORE_DATA:
+		params->next = rets;
+		fallthrough;
+	case RTAS_IBM_GET_INDICES_COMPLETE:
+		params->next = 0;
+		ret = 0;
+		break;
+	default:
+		ret = -EIO;
+		pr_err_ratelimited("unexpected ibm,get-indices status %d\n", fwrc);
+		break;
+	}
+
+	params->status = fwrc;
+	return ret;
+}
+
+/*
+ * Internal indices sequence APIs. A sequence is a series of calls to
+ * ibm,get-indices for a given location code. The sequence ends when
+ * an error is encountered or all indices for the input has been
+ * returned.
+ */
+
+/**
+ * indices_sequence_begin() - Begin a indices retrieval sequence.
+ * @seq:      Uninitialized sequence state.
+ * @params: Indices call parameters and initialization
+ *
+ * Initializes @seq with the resources necessary to carry out indices
+ * call sequence. Callers must pass @seq to indices_sequence_end()
+ * regardless of whether the sequence succeeds.
+ *
+ * Context: May sleep.
+ */
+static void indices_sequence_begin(struct papr_rtas_sequence *seq,
+				void *params)
+{
+	struct rtas_get_indices_params  *param;
+
+	param = (struct rtas_get_indices_params *)params;
+	/*
+	 * We could allocate the work area before acquiring the
+	 * function lock, but that would allow concurrent requests to
+	 * exhaust the limited work area pool for no benefit. So
+	 * allocate the work area under the lock.
+	 */
+	mutex_lock(&rtas_ibm_get_indices_lock);
+	param->work_area = rtas_work_area_alloc(RTAS_GET_INDICES_BUF_SIZE);
+	param->next = 1;
+	param->status = 0;
+	seq->params = param;
+}
+
+/**
+ * indices_sequence_end() - Finalize a indices retrieval sequence.
+ * @seq: indices call parameters from sequence struct
+ *
+ * Releases resources obtained by indices_sequence_begin().
+ */
+static void indices_sequence_end(struct papr_rtas_sequence *seq)
+{
+	struct rtas_get_indices_params *param;
+
+	param =  (struct rtas_get_indices_params *)seq->params;
+	rtas_work_area_free(param->work_area);
+	mutex_unlock(&rtas_ibm_get_indices_lock);
+}
+
+/**
+ * indices_sequence_should_stop() - Determine whether a indices
+ *                                  retrieval sequence should continue.
+ * @seq: indices sequence state.
+ *
+ * Examines the sequence error state and outputs of the last call to
+ * ibm,get-indices to determine whether the sequence in progress should
+ * continue or stop.
+ *
+ * Return: True if the sequence has encountered an error or if all
+ *         indices for this sequence has been retrieved. False otherwise.
+ */
+static bool indices_sequence_should_stop(const struct papr_rtas_sequence *seq)
+{
+	struct rtas_get_indices_params *param;
+	bool done;
+
+	if (seq->error)
+		return true;
+
+	param =  (struct rtas_get_indices_params *)seq->params;
+
+	switch (param->status) {
+	case RTAS_IBM_GET_INDICES_COMPLETE:
+		if (param->next == 1)
+			done = false; /* Initial state. */
+		else
+			done = true; /* All data consumed. */
+		break;
+	case RTAS_IBM_GET_INDICES_MORE_DATA:
+		done = false; /* More data available. */
+		break;
+	default:
+		done = true; /* Error encountered. */
+		break;
+	}
+
+	return done;
+}
+
+/**
+ * Work function to be passed to papr_rtas_blob_generate().
+ *
+ * ibm,get-indices RTAS call fills the work area with the certain
+ * format but does not return the bytes written in the buffer. So
+ * instead of kernel parsing this work area to determine the buffer
+ * length, copy the complete work area (RTAS_GET_INDICES_BUF_SIZE)
+ * to the blob and let the user space to obtain the data.
+ * Means RTAS_GET_INDICES_BUF_SIZE data will be returned for each
+ * read().
+ */
+
+static const char *indices_sequence_fill_work_area(struct papr_rtas_sequence *seq,
+						size_t *len)
+{
+	struct rtas_get_indices_params *p;
+
+	p = (struct rtas_get_indices_params *)seq->params;
+
+	if (indices_sequence_should_stop(seq))
+		return NULL;
+	if (papr_rtas_sequence_set_err(seq, rtas_ibm_get_indices(p)))
+		return NULL;
+	*len = RTAS_GET_INDICES_BUF_SIZE;
+	return rtas_work_area_raw_buf(p->work_area);
+}
+
+/**
+ * papr_indices_handle_read - returns indices blob data to the user space
+ *
+ * ibm,get-indices RTAS call fills the work area with the certian
+ * format but does not return the bytes written in the buffer and
+ * copied RTAS_GET_INDICES_BUF_SIZE data to the blob for each RTAS
+ * call. So send RTAS_GET_INDICES_BUF_SIZE buffer to the user space
+ * for each read().
+ */
+static ssize_t papr_indices_handle_read(struct file *file,
+		char __user *buf, size_t size, loff_t *off)
+{
+	const struct papr_rtas_blob *blob = file->private_data;
+
+	/* we should not instantiate a handle without any data attached. */
+	if (!papr_rtas_blob_has_data(blob)) {
+		pr_err_once("handle without data\n");
+		return -EIO;
+	}
+
+	if (size < RTAS_GET_INDICES_BUF_SIZE) {
+		pr_err_once("Invalid buffer length %ld, expect %d\n",
+				size, RTAS_GET_INDICES_BUF_SIZE);
+		return -EINVAL;
+	} else if (size > RTAS_GET_INDICES_BUF_SIZE)
+		size = RTAS_GET_INDICES_BUF_SIZE;
+
+	return simple_read_from_buffer(buf, size, off, blob->data, blob->len);
+}
+
+static int papr_indices_handle_release(struct inode *inode, struct file *file)
+{
+	const struct papr_rtas_blob *blob = file->private_data;
+
+	papr_rtas_blob_free(blob);
+
+	return 0;
+}
+
+static loff_t papr_indices_handle_seek(struct file *file, loff_t off,
+					int whence)
+{
+	const struct papr_rtas_blob *blob = file->private_data;
+
+	return fixed_size_llseek(file, off, whence, blob->len);
+}
+
+static const struct file_operations papr_indices_handle_ops = {
+	.read = papr_indices_handle_read,
+	.llseek = papr_indices_handle_seek,
+	.release = papr_indices_handle_release,
+};
+
+/**
+ * papr_indices_create_handle() - Create a fd-based handle for reading
+ *                                indices data
+ * @ubuf: Input parameters to RTAS call such as whether sensor or indicator
+ *        and indice type in user memory
+ *
+ * Handler for PAPR_INDICES_IOC_GET ioctl command. Validates @ubuf
+ * and instantiates an immutable indices "blob" for it. The blob is
+ * attached to a file descriptor for reading by user space. The memory
+ * backing the blob is freed when the file is released.
+ *
+ * The entire requested indices is retrieved by this call and all
+ * necessary RTAS interactions are performed before returning the fd
+ * to user space. This keeps the read handler simple and ensures that
+ * the kernel can prevent interleaving of ibm,get-indices call sequences.
+ *
+ * Return: The installed fd number if successful, -ve errno otherwise.
+ */
+static long papr_indices_create_handle(struct papr_indices_io_block __user *ubuf)
+{
+	struct papr_rtas_sequence seq = {};
+	struct rtas_get_indices_params params = {};
+	int fd;
+
+	if (get_user(params.is_sensor, &ubuf->indices.is_sensor))
+		return -EFAULT;
+
+	if (get_user(params.indice_type, &ubuf->indices.indice_type))
+		return -EFAULT;
+
+	seq = (struct papr_rtas_sequence) {
+		.begin = indices_sequence_begin,
+		.end = indices_sequence_end,
+		.work = indices_sequence_fill_work_area,
+	};
+
+	fd = papr_rtas_setup_file_interface(&seq, &params,
+			&papr_indices_handle_ops, "[papr-indices]");
+
+	return fd;
+}
+
+/*
+ * Top-level ioctl handler for /dev/papr-indices.
+ */
+static long papr_indices_dev_ioctl(struct file *filp, unsigned int ioctl,
+				unsigned long arg)
+{
+	void __user *argp = (__force void __user *)arg;
+	long ret;
+
+	switch (ioctl) {
+	case PAPR_INDICES_IOC_GET:
+		ret = papr_indices_create_handle(argp);
+		break;
+	default:
+		ret = -ENOIOCTLCMD;
+		break;
+	}
+
+	return ret;
+}
+
+static const struct file_operations papr_indices_ops = {
+	.unlocked_ioctl = papr_indices_dev_ioctl,
+};
+
+static struct miscdevice papr_indices_dev = {
+	.minor = MISC_DYNAMIC_MINOR,
+	.name = "papr-indices",
+	.fops = &papr_indices_ops,
+};
+
+static __init int papr_indices_init(void)
+{
+	if (!rtas_function_implemented(RTAS_FN_IBM_GET_INDICES))
+		return -ENODEV;
+
+	return misc_register(&papr_indices_dev);
+}
+machine_device_initcall(pseries, papr_indices_init);
-- 
2.43.5

[PATCH 4/6] powerpc/pseries: Add ibm,set-dynamic-indicator RTAS call support

[Haren Myneni]

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>
---
 arch/powerpc/include/asm/rtas.h               |   1 +
 arch/powerpc/kernel/rtas.c                    |   2 +-
 arch/powerpc/platforms/pseries/papr-indices.c | 119 ++++++++++++++++++
 3 files changed, 121 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/include/asm/rtas.h b/arch/powerpc/include/asm/rtas.h
index 7dc527a5aaac..2da52f59e4c6 100644
--- a/arch/powerpc/include/asm/rtas.h
+++ b/arch/powerpc/include/asm/rtas.h
@@ -516,6 +516,7 @@ 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
 
diff --git a/arch/powerpc/kernel/rtas.c b/arch/powerpc/kernel/rtas.c
index 76c634b92cb2..88fa416730af 100644
--- a/arch/powerpc/kernel/rtas.c
+++ b/arch/powerpc/kernel/rtas.c
@@ -95,9 +95,9 @@ static DEFINE_MUTEX(rtas_ibm_activate_firmware_lock);
 static DEFINE_MUTEX(rtas_ibm_get_dynamic_sensor_state_lock);
 static DEFINE_MUTEX(rtas_ibm_lpar_perftools_lock);
 static DEFINE_MUTEX(rtas_ibm_physical_attestation_lock);
-static DEFINE_MUTEX(rtas_ibm_set_dynamic_indicator_lock);
 DEFINE_MUTEX(rtas_ibm_get_vpd_lock);
 DEFINE_MUTEX(rtas_ibm_get_indices_lock);
+DEFINE_MUTEX(rtas_ibm_set_dynamic_indicator_lock);
 
 static struct rtas_function rtas_function_table[] __ro_after_init = {
 	[RTAS_FNIDX__CHECK_EXCEPTION] = {
diff --git a/arch/powerpc/platforms/pseries/papr-indices.c b/arch/powerpc/platforms/pseries/papr-indices.c
index d73aa329bd70..30dfd928d192 100644
--- a/arch/powerpc/platforms/pseries/papr-indices.c
+++ b/arch/powerpc/platforms/pseries/papr-indices.c
@@ -27,6 +27,15 @@
 #define RTAS_IBM_GET_INDICES_MORE_DATA   1 /* More data is available. */
 #define RTAS_IBM_GET_INDICES_START_OVER -4 /* Indices list changed, restart call sequence. */
 
+/*
+ * Function-specific return values for ibm,set-dynamic-indicator and
+ * ibm,get-dynamic-sensor-state RTAS calls, drived from PAPR+
+ * v2.13 7.3.18 and 7.3.19.
+ */
+#define RTAS_IBM_DYNAMIC_INDICE_SUCCESS		0
+#define RTAS_IBM_DYNAMIC_INDICE_HW_ERROR	-1
+#define RTAS_IBM_DYNAMIC_INDICE_NO_INDICATOR	-3
+
 /**
  * struct rtas_ibm_get_indices_params - Parameters (in and out) for
  *                                      ibm,get-indices.
@@ -328,6 +337,107 @@ 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_function_token(RTAS_FN_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))
+		return PTR_ERR(work_area);
+
+	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);
+	mutex_unlock(&rtas_ibm_set_dynamic_indicator_lock);
+
+	switch (fwrc) {
+	case RTAS_IBM_DYNAMIC_INDICE_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_IBM_DYNAMIC_INDICE_HW_ERROR:	/* Hardware/platform error */
+		ret = -EIO;
+		break;
+	}
+
+	return ret;
+}
+
 /*
  * Top-level ioctl handler for /dev/papr-indices.
  */
@@ -341,6 +451,12 @@ 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;
@@ -364,6 +480,9 @@ static __init int papr_indices_init(void)
 	if (!rtas_function_implemented(RTAS_FN_IBM_GET_INDICES))
 		return -ENODEV;
 
+	if (!rtas_function_implemented(RTAS_FN_IBM_SET_DYNAMIC_INDICATOR))
+		return -ENODEV;
+
 	return misc_register(&papr_indices_dev);
 }
 machine_device_initcall(pseries, papr_indices_init);
-- 
2.43.5

[PATCH 5/6] powerpc/pseries: Add ibm,get-dynamic-sensor-state RTAS call support

[Haren Myneni]

The RTAS call ibm,get-dynamic-sensor-state is used to get the
sensor state identified by the location code and the sensor
token. The librtas library provides an API
rtas_get_dynamic_sensor() which uses /dev/mem access for work
area allocation but is restricted under system lockdown.

This patch provides an interface with new ioctl
 PAPR_DYNAMIC_SENSOR_IOC_GET to the papr-indices character
driver which executes this HCALL and copies the sensor state
in the user specified ioctl buffer.

Refer PAPR 7.3.19 ibm,get-dynamic-sensor-state for more
information on this RTAS call.
- User input parameters to the RTAS call: location code string
  and the sensor token

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_SENSOR_IOC_GET,
		struct papr_indices_io_block)
  - The user space specifies input parameters in
    papr_indices_io_block struct
  - Returned state for the specified sensor is copied to
    papr_indices_io_block.dynamic_param.state

Signed-off-by: Haren Myneni <haren@linux.ibm.com>
---
 arch/powerpc/include/asm/rtas.h               |  1 +
 arch/powerpc/kernel/rtas.c                    |  2 +-
 arch/powerpc/platforms/pseries/papr-indices.c | 64 +++++++++++++++++++
 3 files changed, 66 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/include/asm/rtas.h b/arch/powerpc/include/asm/rtas.h
index 2da52f59e4c6..fcd822f0e1d7 100644
--- a/arch/powerpc/include/asm/rtas.h
+++ b/arch/powerpc/include/asm/rtas.h
@@ -517,6 +517,7 @@ 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;
+extern struct mutex rtas_ibm_get_dynamic_sensor_state_lock;
 
 #define GLOBAL_INTERRUPT_QUEUE 9005
 
diff --git a/arch/powerpc/kernel/rtas.c b/arch/powerpc/kernel/rtas.c
index 88fa416730af..a4848e7f248e 100644
--- a/arch/powerpc/kernel/rtas.c
+++ b/arch/powerpc/kernel/rtas.c
@@ -92,12 +92,12 @@ struct rtas_function {
  * Per-function locks for sequence-based RTAS functions.
  */
 static DEFINE_MUTEX(rtas_ibm_activate_firmware_lock);
-static DEFINE_MUTEX(rtas_ibm_get_dynamic_sensor_state_lock);
 static DEFINE_MUTEX(rtas_ibm_lpar_perftools_lock);
 static DEFINE_MUTEX(rtas_ibm_physical_attestation_lock);
 DEFINE_MUTEX(rtas_ibm_get_vpd_lock);
 DEFINE_MUTEX(rtas_ibm_get_indices_lock);
 DEFINE_MUTEX(rtas_ibm_set_dynamic_indicator_lock);
+DEFINE_MUTEX(rtas_ibm_get_dynamic_sensor_state_lock);
 
 static struct rtas_function rtas_function_table[] __ro_after_init = {
 	[RTAS_FNIDX__CHECK_EXCEPTION] = {
diff --git a/arch/powerpc/platforms/pseries/papr-indices.c b/arch/powerpc/platforms/pseries/papr-indices.c
index 30dfd928d192..079e01d0427c 100644
--- a/arch/powerpc/platforms/pseries/papr-indices.c
+++ b/arch/powerpc/platforms/pseries/papr-indices.c
@@ -438,6 +438,64 @@ static long papr_dynamic_indicator_ioc_set(struct papr_indices_io_block __user *
 	return ret;
 }
 
+/**
+ * papr_dynamic_sensor_ioc_get - ibm,get-dynamic-sensor-state RTAS Call
+ * PAPR 2.13 7.3.19
+ *
+ * @ubuf: Input parameters to RTAS call such as sensor token
+ *        Copies the state in user space buffer.
+ *
+ *
+ * Returns success or -errno.
+ */
+
+static long papr_dynamic_sensor_ioc_get(struct papr_indices_io_block __user *ubuf)
+{
+	struct papr_indices_io_block kbuf;
+	struct rtas_work_area *work_area;
+	s32 fwrc, token, ret;
+	u32 rets;
+
+	token = rtas_function_token(RTAS_FN_IBM_GET_DYNAMIC_SENSOR_STATE);
+	if (token == RTAS_UNKNOWN_SERVICE)
+		return -ENOENT;
+
+	mutex_lock(&rtas_ibm_get_dynamic_sensor_state_lock);
+	work_area = papr_dynamic_indice_buf_from_user(ubuf, &kbuf);
+	if (IS_ERR(work_area))
+		return PTR_ERR(work_area);
+
+	do {
+		fwrc = rtas_call(token, 2, 2, &rets,
+				kbuf.dynamic_param.token,
+				rtas_work_area_phys(work_area));
+	} while (rtas_busy_delay(fwrc));
+
+	rtas_work_area_free(work_area);
+	mutex_unlock(&rtas_ibm_get_dynamic_sensor_state_lock);
+
+	switch (fwrc) {
+	case RTAS_IBM_DYNAMIC_INDICE_SUCCESS:
+		if (put_user(rets, &ubuf->dynamic_param.state))
+			ret = -EFAULT;
+		else
+			ret = 0;
+		break;
+	case RTAS_IBM_DYNAMIC_INDICE_NO_INDICATOR:	/* No such indicator */
+		ret = -EOPNOTSUPP;
+		break;
+	default:
+		pr_err("unexpected ibm,get-dynamic-sensor result %d\n",
+				fwrc);
+		fallthrough;
+	case RTAS_IBM_DYNAMIC_INDICE_HW_ERROR:	/* Hardware/platform error */
+		ret = -EIO;
+		break;
+	}
+
+	return ret;
+}
+
 /*
  * Top-level ioctl handler for /dev/papr-indices.
  */
@@ -451,6 +509,9 @@ 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_SENSOR_IOC_GET:
+		ret = papr_dynamic_sensor_ioc_get(argp);
+		break;
 	case PAPR_DYNAMIC_INDICATOR_IOC_SET:
 		if (filp->f_mode & FMODE_WRITE)
 			ret = papr_dynamic_indicator_ioc_set(argp);
@@ -483,6 +544,9 @@ static __init int papr_indices_init(void)
 	if (!rtas_function_implemented(RTAS_FN_IBM_SET_DYNAMIC_INDICATOR))
 		return -ENODEV;
 
+	if (!rtas_function_implemented(RTAS_FN_IBM_GET_DYNAMIC_SENSOR_STATE))
+		return -ENODEV;
+
 	return misc_register(&papr_indices_dev);
 }
 machine_device_initcall(pseries, papr_indices_init);
-- 
2.43.5

[PATCH 6/6] powerpc/pseries: Add papr-platform-dump character driver for dump retrieval

[Haren Myneni]

ibm,platform-dump RTAS call in combination with writable mapping
/dev/mem is issued to collect platform dump from the hypervisor
and may need multiple calls to get the complete dump. The current
implementation uses rtas_platform_dump() API provided by librtas
library to issue these HCALLs. But /dev/mem access by the user
space is prohibited under system lockdown.

The solution should be to restrict access to RTAS function in user
space and provide kernel interfaces to collect dump. This patch
adds papr-platform-dump character driver and expose standard
interfaces such as open / ioctl/ read to user space in ways that
are compatible with lockdown.

PAPR (7.3.3.4.1 ibm,platform-dump) provides a method to obtain
the complete dump:
- Each dump will be identified by ID called dump tag.
- A sequence of RTAS calls have to be issued until retrieve the
  complete dump. The hypervisor expects the first RTAS call with
  the sequence 0 and the subsequent calls with the sequence
  number returned from the previous calls.
- The hypervisor returns "dump complete" status once the complete
  dump is retrieved. But expects one more RTAS call from the
  partition with the NULL buffer to invalidate dump which means
  the dump will be removed in the hypervisor.
- Sequence of calls are allowed with different dump IDs at the
  same time but not with the same dump ID.

Expose these interfaces to user space with a /dev/papr-platform-dump
character device using the following programming model:

   int devfd = open("/dev/papr-platform-dump", O_RDONLY);
   int fd = ioctl(devfd,PAPR_PLATFORM_DUMP_IOC_CREATE_HANDLE, &dump_id)
	- Restrict user space to access with the same dump ID.
          Typically we do not expect user space requests the dump
          again for the same dump ID.
   char *buf = malloc(size);
   length = read(fd, buf, size);
        - size should be minimum 1K based on PAPR and  <= 4K based
          on RTAS work area size. It will be restrict to RTAS work
          area size. Using 4K work area based on the current
          implementation in librtas library
        - Each read call issue RTAS call to get the data based on
          the size requirement and returns bytes returned from the
          hypervisor
        - If the previous HCALL returns dump complete status, the
          next read returns 0 like EOF.
   ret = ioctl(PAPR_PLATFORM_DUMP_IOC_INVALIDATE, &dump_id)
	- RTAS call with NULL buffer to invalidates the dump.

The read API should use the file descriptor obtained from ioctl
based on dump ID so that gets dump contents for the corresponding
dump ID. Implemented support in librtas (rtas_platform_dump()) for
this new ABI to support system lockdown.

Signed-off-by: Haren Myneni <haren@linux.ibm.com>
---
 .../include/uapi/asm/papr-platform-dump.h     |  15 +
 arch/powerpc/platforms/pseries/Makefile       |   1 +
 .../platforms/pseries/papr-platform-dump.c    | 408 ++++++++++++++++++
 3 files changed, 424 insertions(+)
 create mode 100644 arch/powerpc/include/uapi/asm/papr-platform-dump.h
 create mode 100644 arch/powerpc/platforms/pseries/papr-platform-dump.c

diff --git a/arch/powerpc/include/uapi/asm/papr-platform-dump.h b/arch/powerpc/include/uapi/asm/papr-platform-dump.h
new file mode 100644
index 000000000000..3a0f152e3ce8
--- /dev/null
+++ b/arch/powerpc/include/uapi/asm/papr-platform-dump.h
@@ -0,0 +1,15 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+#ifndef _UAPI_PAPR_PLATFORM_DUMP_H_
+#define _UAPI_PAPR_PLATFORM_DUMP_H_
+
+#include <asm/ioctl.h>
+#include <asm/papr-miscdev.h>
+
+/*
+ * ioctl for /dev/papr-platform-dump. Returns a VPD handle fd corresponding to
+ * the location code.
+ */
+#define PAPR_PLATFORM_DUMP_IOC_CREATE_HANDLE _IOW(PAPR_MISCDEV_IOC_ID, 6, __u64)
+#define PAPR_PLATFORM_DUMP_IOC_INVALIDATE    _IOW(PAPR_MISCDEV_IOC_ID, 7, __u64)
+
+#endif /* _UAPI_PAPR_PLATFORM_DUMP_H_ */
diff --git a/arch/powerpc/platforms/pseries/Makefile b/arch/powerpc/platforms/pseries/Makefile
index e1db61877bb9..c82c94e0a73c 100644
--- a/arch/powerpc/platforms/pseries/Makefile
+++ b/arch/powerpc/platforms/pseries/Makefile
@@ -4,6 +4,7 @@ ccflags-$(CONFIG_PPC_PSERIES_DEBUG)	+= -DDEBUG
 obj-y			:= lpar.o hvCall.o nvram.o reconfig.o \
 			   of_helpers.o rtas-work-area.o papr-sysparm.o \
 			   papr-rtas-common.o papr-vpd.o papr-indices.o \
+			   papr-platform-dump.o \
 			   setup.o iommu.o event_sources.o ras.o \
 			   firmware.o power.o dlpar.o mobility.o rng.o \
 			   pci.o pci_dlpar.o eeh_pseries.o msi.o \
diff --git a/arch/powerpc/platforms/pseries/papr-platform-dump.c b/arch/powerpc/platforms/pseries/papr-platform-dump.c
new file mode 100644
index 000000000000..a78a20ec983e
--- /dev/null
+++ b/arch/powerpc/platforms/pseries/papr-platform-dump.c
@@ -0,0 +1,408 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#define pr_fmt(fmt) "papr-platform-dump: " fmt
+
+#include <linux/anon_inodes.h>
+#include <linux/file.h>
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/miscdevice.h>
+#include <asm/machdep.h>
+#include <asm/rtas-work-area.h>
+#include <asm/rtas.h>
+#include <uapi/asm/papr-platform-dump.h>
+
+/*
+ * Function-specific return values for ibm,platform-dump, derived from
+ * PAPR+ v2.13 7.3.3.4.1 "ibm,platform-dump RTAS Call".
+ */
+#define	RTAS_IBM_PLATFORM_DUMP_COMPLETE	0	/* Complete dump retrieved. */
+#define	RTAS_IBM_PLATFORM_DUMP_CONTINUE	1	/* Continue dump */
+#define	RTAS_NOT_AUTHORIZED		-9002	/* Not Authorized */
+
+#define	RTAS_IBM_PLATFORM_DUMP_START	2 /* Linux status to start dump */
+
+/**
+ * struct ibm_platform_dump_params - Parameters (in and out) for
+ *                                              ibm,platform-dump
+ * @work_area:		In: work area buffer for results.
+ * @buf_length:		In: work area buffer length in bytes
+ * @dump_tag_hi:	In: Most-significant 32 bits of a Dump_Tag representing
+ *                      an id of the dump being processed.
+ * @dump_tag_lo:	In: Least-significant 32 bits of a Dump_Tag representing
+ *                      an id of the dump being processed.
+ * @sequence_hi:	In: Sequence number in most-significant 32 bits.
+ *                      Out: Next sequence number in most-significant 32 bits.
+ * @sequence_lo:	In: Sequence number in Least-significant 32 bits
+ *                      Out: Next sequence number in Least-significant 32 bits.
+ * @bytes_ret_hi:	Out: Bytes written in most-significant 32 bits.
+ * @bytes_ret_lo:	Out: Bytes written in Least-significant 32 bits.
+ * @status:		Out: RTAS call status.
+ * @list:		Maintain the list of dumps are in progress. Can
+ *                      retrieve multiple dumps with different dump IDs at
+ *                      the same time but not with the same dump ID. This list
+ *                      is used to determine whether the dump for the same ID
+ *                      is in progress.
+ */
+struct ibm_platform_dump_params {
+	struct rtas_work_area	*work_area;
+	u32			buf_length;
+	u32			dump_tag_hi;
+	u32			dump_tag_lo;
+	u32			sequence_hi;
+	u32			sequence_lo;
+	u32			bytes_ret_hi;
+	u32			bytes_ret_lo;
+	s32			status;
+	struct list_head	list;
+};
+
+/*
+ * Multiple dumps with different dump IDs can be retrieved at the same
+ * time, but not with dame dump ID. platform_dump_list_mutex and
+ * platform_dump_list are used to prevent this behavior.
+ */
+static DEFINE_MUTEX(platform_dump_list_mutex);
+static LIST_HEAD(platform_dump_list);
+
+/**
+ * rtas_ibm_platform_dump() - Call ibm,platform-dump to fill a work area
+ * buffer.
+ * @params: See &struct ibm_platform_dump_params.
+ * @buf_addr: Address of dump buffer (work_area)
+ * @buf_length: Length of the buffer in bytes (min. 1024)
+ *
+ * Calls ibm,platform-dump until it errors or successfully deposits data
+ * into the supplied work area. Handles RTAS retry statuses. Maps RTAS
+ * error statuses to reasonable errno values.
+ *
+ * Can request multiple dumps with different dump IDs at the same time,
+ * but not with the same dump ID which is prevented with the check in
+ * the ioctl code (papr_platform_dump_create_handle()).
+ *
+ * The caller should inspect @params.status to determine whether more
+ * calls are needed to complete the sequence.
+ *
+ * Context: May sleep.
+ * Return: -ve on error, 0 for dump complete and 1 for continue dump
+ */
+static int rtas_ibm_platform_dump(struct ibm_platform_dump_params *params,
+				phys_addr_t buf_addr, u32 buf_length)
+{
+	u32 rets[4];
+	s32 fwrc;
+	int ret = 0;
+
+	do {
+		fwrc = rtas_call(rtas_function_token(RTAS_FN_IBM_PLATFORM_DUMP),
+				6, 5,
+				rets,
+				params->dump_tag_hi,
+				params->dump_tag_lo,
+				params->sequence_hi,
+				params->sequence_lo,
+				buf_addr,
+				buf_length);
+	} while (rtas_busy_delay(fwrc));
+
+	switch (fwrc) {
+	case RTAS_HARDWARE_ERROR:
+		ret = -EIO;
+		break;
+	case RTAS_NOT_AUTHORIZED:
+		ret = -EPERM;
+		break;
+	case RTAS_IBM_PLATFORM_DUMP_CONTINUE:
+	case RTAS_IBM_PLATFORM_DUMP_COMPLETE:
+		params->sequence_hi = rets[0];
+		params->sequence_lo = rets[1];
+		params->bytes_ret_hi = rets[2];
+		params->bytes_ret_lo = rets[3];
+		break;
+	default:
+		ret = -EIO;
+		pr_err_ratelimited("unexpected ibm,platform-dump status %d\n",
+				fwrc);
+		break;
+	}
+
+	params->status = fwrc;
+	return ret;
+}
+
+/*
+ * Platform dump is used with multiple RTAS calls to retrieve the
+ * complete dump for the provided dump ID. Once the complete dump is
+ * retrieved, the hypervisor returns dump complete status (0) for the
+ * last RTAS call and expects the caller issues one more HCALL with
+ * NULL buffer to invalidate the dump so that the hypervisor can remove
+ * the dump.
+ *
+ * After the specific dump is invalidated in the hypervisor, expect the
+ * dump complete status for the new sequence - the user space initiates
+ * new request for the same dump ID.
+ */
+static ssize_t papr_platform_dump_handle_read(struct file *file,
+		char __user *buf, size_t size, loff_t *off)
+{
+	struct ibm_platform_dump_params *params = file->private_data;
+	u64 total_bytes;
+	s32 fwrc;
+
+	/*
+	 * Dump already completed with the previous read calls.
+	 * In case if the user space issues further reads, returns
+	 * -EINVAL.
+	 */
+	if (!params->buf_length) {
+		pr_warn_once("Platform dump completed for dump ID %llu\n",
+			(u64) (((u64)params->dump_tag_hi << 32) |
+				params->dump_tag_lo));
+		return -EINVAL;
+	}
+
+	/*
+	 * The hypervisor returns status 0 if no more data available to
+	 * download. The dump will be invalidated with ioctl (see below).
+	 */
+	if (params->status == RTAS_IBM_PLATFORM_DUMP_COMPLETE) {
+		params->buf_length = 0;
+		/*
+		 * Returns 0 to the user space so that user
+		 * space read stops.
+		 */
+		return 0;
+	}
+
+	if (size < SZ_1K) {
+		pr_err_once("Buffer length should be minimum 1024 bytes\n");
+		return -EINVAL;
+	} else if (size > params->buf_length) {
+		/*
+		 * Allocate 4K work area. So if the user requests > 4K,
+		 * resize the buffer length.
+		 */
+		size = params->buf_length;
+	}
+
+	fwrc = rtas_ibm_platform_dump(params,
+			rtas_work_area_phys(params->work_area),
+			size);
+	if (fwrc < 0)
+		return fwrc;
+
+	total_bytes = (u64) (((u64)params->bytes_ret_hi << 32) |
+			params->bytes_ret_lo);
+
+	/*
+	 * Kernel or firmware bug, do not continue.
+	 */
+	if (WARN(total_bytes > size, "possible write beyond end of work area"))
+		return -EFAULT;
+
+	if (copy_to_user(buf, rtas_work_area_raw_buf(params->work_area),
+			total_bytes))
+		return -EFAULT;
+
+	return total_bytes;
+}
+
+static int papr_platform_dump_handle_release(struct inode *inode,
+					struct file *file)
+{
+	struct ibm_platform_dump_params *params = file->private_data;
+
+	if (params->work_area)
+		rtas_work_area_free(params->work_area);
+
+	mutex_lock(&platform_dump_list_mutex);
+	list_del(&params->list);
+	mutex_unlock(&platform_dump_list_mutex);
+
+	kfree(params);
+	file->private_data = NULL;
+	return 0;
+}
+
+/*
+ * This ioctl is used to invalidate the dump assuming the user space
+ * issue this ioctl after obtain the complete dump.
+ * Issue the last RTAS call with NULL buffer to invalidate the dump
+ * which means dump will be freed in the hypervisor.
+ */
+static long papr_platform_dump_invalidate_ioctl(struct file *file,
+				unsigned int ioctl, unsigned long arg)
+{
+	struct ibm_platform_dump_params *params;
+	u64 __user *argp = (void __user *)arg;
+	u64 param_dump_tag, dump_tag;
+
+	if (ioctl != PAPR_PLATFORM_DUMP_IOC_INVALIDATE)
+		return -ENOIOCTLCMD;
+
+	if (get_user(dump_tag, argp))
+		return -EFAULT;
+
+	/*
+	 * private_data is freeded during release(), so should not
+	 * happen.
+	 */
+	if (!file->private_data) {
+		pr_err("No valid FD to invalidate dump for the ID(%llu)\n",
+				dump_tag);
+		return -EINVAL;
+	}
+
+	params = file->private_data;
+	param_dump_tag = (u64) (((u64)params->dump_tag_hi << 32) |
+				params->dump_tag_lo);
+	if (dump_tag != param_dump_tag) {
+		pr_err("Invalid dump ID(%llu) to invalidate dump\n",
+				dump_tag);
+		return -EINVAL;
+	}
+
+	if (params->status != RTAS_IBM_PLATFORM_DUMP_COMPLETE)
+		pr_warn("Platform dump is not complete, but requested "
+			"to invalidate dump for ID(%llu)\n",
+			dump_tag);
+
+	return rtas_ibm_platform_dump(params, 0, 0);
+}
+
+static const struct file_operations papr_platform_dump_handle_ops = {
+	.read = papr_platform_dump_handle_read,
+	.release = papr_platform_dump_handle_release,
+	.unlocked_ioctl	= papr_platform_dump_invalidate_ioctl,
+};
+
+/**
+ * papr_platform_dump_create_handle() - Create a fd-based handle for
+ * reading platform dump
+ *
+ * Handler for PAPR_PLATFORM_DUMP_IOC_CREATE_HANDLE ioctl command
+ * Allocates RTAS parameter struct and work area and attached to the
+ * file descriptor for reading by user space with the multiple RTAS
+ * calls until the dump is completed. This memory allocation is freed
+ * when the file is released.
+ *
+ * Multiple dump requests with different IDs are allowed at the same
+ * time, but not with the same dump ID. So if the user space is
+ * already opened file descriptor for the specific dump ID, return
+ * -EALREADY for the next request.
+ *
+ * @dump_tag: Dump ID for the dump requested to retrieve from the
+ *		hypervisor
+ *
+ * Return: The installed fd number if successful, -ve errno otherwise.
+ */
+static long papr_platform_dump_create_handle(u64 dump_tag)
+{
+	struct ibm_platform_dump_params *params;
+	u64 param_dump_tag;
+	struct file *file;
+	long err;
+	int fd;
+
+	/*
+	 * Return failure if the user space is already opened FD for
+	 * the specific dump ID. This check will prevent multiple dump
+	 * requests for the same dump ID at the same time. Generally
+	 * should not expect this, but in case.
+	 */
+	list_for_each_entry(params, &platform_dump_list, list) {
+		param_dump_tag = (u64) (((u64)params->dump_tag_hi << 32) |
+					params->dump_tag_lo);
+		if (dump_tag == param_dump_tag) {
+			pr_err("Platform dump for ID(%llu) is already in progress\n",
+					dump_tag);
+			return -EALREADY;
+		}
+	}
+
+	params =  kzalloc(sizeof(struct ibm_platform_dump_params),
+			GFP_KERNEL_ACCOUNT);
+	if (!params)
+		return -ENOMEM;
+
+	params->work_area = rtas_work_area_alloc(SZ_4K);
+	params->buf_length = SZ_4K;
+	params->dump_tag_hi = (u32)(dump_tag >> 32);
+	params->dump_tag_lo = (u32)(dump_tag & 0x00000000ffffffffULL);
+	params->status = RTAS_IBM_PLATFORM_DUMP_START;
+
+	fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC);
+	if (fd < 0) {
+		err = fd;
+		goto put_fd;
+	}
+
+	file = anon_inode_getfile("[papr-platform-dump]",
+				&papr_platform_dump_handle_ops,
+				(void *)params, O_RDONLY);
+	if (IS_ERR(file)) {
+		err = PTR_ERR(file);
+		goto put_fd;
+	}
+
+	file->f_mode |= FMODE_LSEEK | FMODE_PREAD;
+	fd_install(fd, file);
+
+	list_add(&params->list, &platform_dump_list);
+
+	pr_info("%s (%d) initiated platform dump for dump tag %llu\n",
+		current->comm, current->pid, dump_tag);
+	return fd;
+put_fd:
+	rtas_work_area_free(params->work_area);
+	kfree(params);
+	put_unused_fd(fd);
+	return err;
+}
+
+/*
+ * Top-level ioctl handler for /dev/papr-platform-dump.
+ */
+static long papr_platform_dump_dev_ioctl(struct file *filp,
+					unsigned int ioctl,
+					unsigned long arg)
+{
+	u64 __user *argp = (void __user *)arg;
+	u64 dump_tag;
+	long ret;
+
+	if (get_user(dump_tag, argp))
+		return -EFAULT;
+
+	switch (ioctl) {
+	case PAPR_PLATFORM_DUMP_IOC_CREATE_HANDLE:
+		mutex_lock(&platform_dump_list_mutex);
+		ret = papr_platform_dump_create_handle(dump_tag);
+		mutex_unlock(&platform_dump_list_mutex);
+		break;
+	default:
+		ret = -ENOIOCTLCMD;
+		break;
+	}
+	return ret;
+}
+
+static const struct file_operations papr_platform_dump_ops = {
+	.unlocked_ioctl = papr_platform_dump_dev_ioctl,
+};
+
+static struct miscdevice papr_platform_dump_dev = {
+	.minor = MISC_DYNAMIC_MINOR,
+	.name = "papr-platform-dump",
+	.fops = &papr_platform_dump_ops,
+};
+
+static __init int papr_platform_dump_init(void)
+{
+	if (!rtas_function_implemented(RTAS_FN_IBM_PLATFORM_DUMP))
+		return -ENODEV;
+
+	return misc_register(&papr_platform_dump_dev);
+}
+machine_device_initcall(pseries, papr_platform_dump_init);
-- 
2.43.5

Re: [PATCH 1/6] powerpc/pseries: Define common functions for RTAS sequence HCALLs

[kernel test robot]

Hi Haren,

kernel test robot noticed the following build warnings:

[auto build test WARNING on powerpc/next]
[also build test WARNING on powerpc/fixes linus/master v6.13-rc5 next-20241220]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Haren-Myneni/powerpc-pseries-Define-common-functions-for-RTAS-sequence-HCALLs/20250105-045010
base:   https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git next
patch link:    https://lore.kernel.org/r/20250104204652.388720-2-haren%40linux.ibm.com
patch subject: [PATCH 1/6] powerpc/pseries: Define common functions for RTAS sequence HCALLs
config: powerpc64-randconfig-002-20250105 (https://download.01.org/0day-ci/archive/20250105/202501051055.oZDoR4fH-lkp@intel.com/config)
compiler: clang version 20.0.0git (https://github.com/llvm/llvm-project 096551537b2a747a3387726ca618ceeb3950e9bc)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250105/202501051055.oZDoR4fH-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202501051055.oZDoR4fH-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> arch/powerpc/platforms/pseries/papr-vpd.c:141: warning: Function parameter or struct member 'param' not described in 'vpd_sequence_begin'
>> arch/powerpc/platforms/pseries/papr-vpd.c:141: warning: Excess function parameter 'loc_code' description in 'vpd_sequence_begin'


vim +141 arch/powerpc/platforms/pseries/papr-vpd.c

514f6ff4369a30 Nathan Lynch 2023-12-12  121  
514f6ff4369a30 Nathan Lynch 2023-12-12  122  /*
514f6ff4369a30 Nathan Lynch 2023-12-12  123   * Internal VPD sequence APIs. A VPD sequence is a series of calls to
514f6ff4369a30 Nathan Lynch 2023-12-12  124   * ibm,get-vpd for a given location code. The sequence ends when an
514f6ff4369a30 Nathan Lynch 2023-12-12  125   * error is encountered or all VPD for the location code has been
514f6ff4369a30 Nathan Lynch 2023-12-12  126   * returned.
514f6ff4369a30 Nathan Lynch 2023-12-12  127   */
514f6ff4369a30 Nathan Lynch 2023-12-12  128  
514f6ff4369a30 Nathan Lynch 2023-12-12  129  /**
514f6ff4369a30 Nathan Lynch 2023-12-12  130   * vpd_sequence_begin() - Begin a VPD retrieval sequence.
514f6ff4369a30 Nathan Lynch 2023-12-12  131   * @seq:      Uninitialized sequence state.
514f6ff4369a30 Nathan Lynch 2023-12-12  132   * @loc_code: Location code that defines the scope of the VPD to return.
514f6ff4369a30 Nathan Lynch 2023-12-12  133   *
514f6ff4369a30 Nathan Lynch 2023-12-12  134   * Initializes @seq with the resources necessary to carry out a VPD
514f6ff4369a30 Nathan Lynch 2023-12-12  135   * sequence. Callers must pass @seq to vpd_sequence_end() regardless
514f6ff4369a30 Nathan Lynch 2023-12-12  136   * of whether the sequence succeeds.
514f6ff4369a30 Nathan Lynch 2023-12-12  137   *
514f6ff4369a30 Nathan Lynch 2023-12-12  138   * Context: May sleep.
514f6ff4369a30 Nathan Lynch 2023-12-12  139   */
5d8b0014124124 Haren Myneni 2025-01-04  140  static void vpd_sequence_begin(struct papr_rtas_sequence *seq, void *param)
514f6ff4369a30 Nathan Lynch 2023-12-12 @141  {
5d8b0014124124 Haren Myneni 2025-01-04  142  	struct rtas_ibm_get_vpd_params *vpd_params;
514f6ff4369a30 Nathan Lynch 2023-12-12  143  	/*
514f6ff4369a30 Nathan Lynch 2023-12-12  144  	 * Use a static data structure for the location code passed to
514f6ff4369a30 Nathan Lynch 2023-12-12  145  	 * RTAS to ensure it's in the RMA and avoid a separate work
514f6ff4369a30 Nathan Lynch 2023-12-12  146  	 * area allocation. Guarded by the function lock.
514f6ff4369a30 Nathan Lynch 2023-12-12  147  	 */
514f6ff4369a30 Nathan Lynch 2023-12-12  148  	static struct papr_location_code static_loc_code;
514f6ff4369a30 Nathan Lynch 2023-12-12  149  
514f6ff4369a30 Nathan Lynch 2023-12-12  150  	/*
514f6ff4369a30 Nathan Lynch 2023-12-12  151  	 * We could allocate the work area before acquiring the
514f6ff4369a30 Nathan Lynch 2023-12-12  152  	 * function lock, but that would allow concurrent requests to
514f6ff4369a30 Nathan Lynch 2023-12-12  153  	 * exhaust the limited work area pool for no benefit. So
514f6ff4369a30 Nathan Lynch 2023-12-12  154  	 * allocate the work area under the lock.
514f6ff4369a30 Nathan Lynch 2023-12-12  155  	 */
514f6ff4369a30 Nathan Lynch 2023-12-12  156  	mutex_lock(&rtas_ibm_get_vpd_lock);
5d8b0014124124 Haren Myneni 2025-01-04  157  	static_loc_code = *(struct papr_location_code *)param;
5d8b0014124124 Haren Myneni 2025-01-04  158  	vpd_params =  (struct rtas_ibm_get_vpd_params *)seq->params;
5d8b0014124124 Haren Myneni 2025-01-04  159  	vpd_params->work_area = rtas_work_area_alloc(SZ_4K);
5d8b0014124124 Haren Myneni 2025-01-04  160  	vpd_params->loc_code = &static_loc_code;
5d8b0014124124 Haren Myneni 2025-01-04  161  	vpd_params->sequence = 1;
5d8b0014124124 Haren Myneni 2025-01-04  162  	vpd_params->status = 0;
514f6ff4369a30 Nathan Lynch 2023-12-12  163  }
514f6ff4369a30 Nathan Lynch 2023-12-12  164  

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Re: [PATCH 3/6] powerpc/pseries: Add papr-indices char driver for ibm,get-indices HCALL

[kernel test robot]

Hi Haren,

kernel test robot noticed the following build warnings:

[auto build test WARNING on powerpc/next]
[also build test WARNING on powerpc/fixes linus/master v6.13-rc5 next-20241220]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Haren-Myneni/powerpc-pseries-Define-common-functions-for-RTAS-sequence-HCALLs/20250105-045010
base:   https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git next
patch link:    https://lore.kernel.org/r/20250104204652.388720-4-haren%40linux.ibm.com
patch subject: [PATCH 3/6] powerpc/pseries: Add papr-indices char driver for ibm,get-indices HCALL
config: powerpc64-randconfig-002-20250105 (https://download.01.org/0day-ci/archive/20250105/202501051117.D90y1VNS-lkp@intel.com/config)
compiler: clang version 20.0.0git (https://github.com/llvm/llvm-project 096551537b2a747a3387726ca618ceeb3950e9bc)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250105/202501051117.D90y1VNS-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202501051117.D90y1VNS-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> arch/powerpc/platforms/pseries/papr-indices.c:45: warning: expecting prototype for struct rtas_ibm_get_indices_params. Prototype was for struct rtas_get_indices_params instead
>> arch/powerpc/platforms/pseries/papr-indices.c:210: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst
    * Work function to be passed to papr_rtas_blob_generate().
>> arch/powerpc/platforms/pseries/papr-indices.c:247: warning: Function parameter or struct member 'file' not described in 'papr_indices_handle_read'
>> arch/powerpc/platforms/pseries/papr-indices.c:247: warning: Function parameter or struct member 'buf' not described in 'papr_indices_handle_read'
>> arch/powerpc/platforms/pseries/papr-indices.c:247: warning: Function parameter or struct member 'size' not described in 'papr_indices_handle_read'
>> arch/powerpc/platforms/pseries/papr-indices.c:247: warning: Function parameter or struct member 'off' not described in 'papr_indices_handle_read'


vim +45 arch/powerpc/platforms/pseries/papr-indices.c

    29	
    30	/**
    31	 * struct rtas_ibm_get_indices_params - Parameters (in and out) for
    32	 *                                      ibm,get-indices.
    33	 * @is_sensor:	In: Caller-provided whether sensor or indicator.
    34	 * @indice_type:In: Caller-provided indice (sensor or indicator) token
    35	 * @work_area:	In: Caller-provided work area buffer for results.
    36	 * @next:	In: Sequence number. Out: Next sequence number.
    37	 * @status:	Out: RTAS call status.
    38	 */
    39	struct rtas_get_indices_params {
    40		u8 is_sensor;
    41		u32 indice_type;
    42		struct rtas_work_area *work_area;
    43		u32 next;
    44		s32 status;
  > 45	};
    46	
    47	/**
    48	 * rtas_ibm_get_indices() - Call ibm,get-indices to fill a work area buffer.
    49	 * @params: See &struct rtas_ibm_get_indices_params.
    50	 *
    51	 * Calls ibm,get-indices until it errors or successfully deposits data
    52	 * into the supplied work area. Handles RTAS retry statuses. Maps RTAS
    53	 * error statuses to reasonable errno values.
    54	 *
    55	 * The caller is expected to invoke rtas_ibm_get_indices() multiple times
    56	 * to retrieve all indices data for the provided indice type. Only one
    57	 * sequence should be in progress at any time; starting a new sequence
    58	 * will disrupt any sequence already in progress. Serialization of
    59	 * indices retrieval sequences is the responsibility of the caller.
    60	 *
    61	 * The caller should inspect @params.status to determine whether more
    62	 * calls are needed to complete the sequence.
    63	 *
    64	 * Context: May sleep.
    65	 * Return: -ve on error, 0 otherwise.
    66	 */
    67	static int rtas_ibm_get_indices(struct rtas_get_indices_params *params)
    68	{
    69		struct rtas_work_area *work_area = params->work_area;
    70		const s32 token = rtas_function_token(RTAS_FN_IBM_GET_INDICES);
    71		u32 rets;
    72		s32 fwrc;
    73		int ret;
    74	
    75		if (token == RTAS_UNKNOWN_SERVICE)
    76			return -ENOENT;
    77	
    78		lockdep_assert_held(&rtas_ibm_get_indices_lock);
    79	
    80		do {
    81			fwrc = rtas_call(token, 5, 2, &rets, params->is_sensor,
    82					params->indice_type,
    83					rtas_work_area_phys(work_area),
    84					rtas_work_area_size(work_area),
    85					params->next);
    86		} while (rtas_busy_delay(fwrc));
    87	
    88		switch (fwrc) {
    89		case RTAS_HARDWARE_ERROR:
    90			ret = -EIO;
    91			break;
    92		case RTAS_INVALID_PARAMETER: /* Indicator type is not supported */
    93			ret = -EINVAL;
    94			break;
    95		case RTAS_IBM_GET_INDICES_START_OVER:
    96			ret = -EAGAIN;
    97			pr_info_ratelimited("Indices changed during retrieval, retrying\n");
    98			params->next = 1;
    99			break;
   100		case RTAS_IBM_GET_INDICES_MORE_DATA:
   101			params->next = rets;
   102			fallthrough;
   103		case RTAS_IBM_GET_INDICES_COMPLETE:
   104			params->next = 0;
   105			ret = 0;
   106			break;
   107		default:
   108			ret = -EIO;
   109			pr_err_ratelimited("unexpected ibm,get-indices status %d\n", fwrc);
   110			break;
   111		}
   112	
   113		params->status = fwrc;
   114		return ret;
   115	}
   116	
   117	/*
   118	 * Internal indices sequence APIs. A sequence is a series of calls to
   119	 * ibm,get-indices for a given location code. The sequence ends when
   120	 * an error is encountered or all indices for the input has been
   121	 * returned.
   122	 */
   123	
   124	/**
   125	 * indices_sequence_begin() - Begin a indices retrieval sequence.
   126	 * @seq:      Uninitialized sequence state.
   127	 * @params: Indices call parameters and initialization
   128	 *
   129	 * Initializes @seq with the resources necessary to carry out indices
   130	 * call sequence. Callers must pass @seq to indices_sequence_end()
   131	 * regardless of whether the sequence succeeds.
   132	 *
   133	 * Context: May sleep.
   134	 */
   135	static void indices_sequence_begin(struct papr_rtas_sequence *seq,
   136					void *params)
   137	{
   138		struct rtas_get_indices_params  *param;
   139	
   140		param = (struct rtas_get_indices_params *)params;
   141		/*
   142		 * We could allocate the work area before acquiring the
   143		 * function lock, but that would allow concurrent requests to
   144		 * exhaust the limited work area pool for no benefit. So
   145		 * allocate the work area under the lock.
   146		 */
   147		mutex_lock(&rtas_ibm_get_indices_lock);
   148		param->work_area = rtas_work_area_alloc(RTAS_GET_INDICES_BUF_SIZE);
   149		param->next = 1;
   150		param->status = 0;
   151		seq->params = param;
   152	}
   153	
   154	/**
   155	 * indices_sequence_end() - Finalize a indices retrieval sequence.
   156	 * @seq: indices call parameters from sequence struct
   157	 *
   158	 * Releases resources obtained by indices_sequence_begin().
   159	 */
   160	static void indices_sequence_end(struct papr_rtas_sequence *seq)
   161	{
   162		struct rtas_get_indices_params *param;
   163	
   164		param =  (struct rtas_get_indices_params *)seq->params;
   165		rtas_work_area_free(param->work_area);
   166		mutex_unlock(&rtas_ibm_get_indices_lock);
   167	}
   168	
   169	/**
   170	 * indices_sequence_should_stop() - Determine whether a indices
   171	 *                                  retrieval sequence should continue.
   172	 * @seq: indices sequence state.
   173	 *
   174	 * Examines the sequence error state and outputs of the last call to
   175	 * ibm,get-indices to determine whether the sequence in progress should
   176	 * continue or stop.
   177	 *
   178	 * Return: True if the sequence has encountered an error or if all
   179	 *         indices for this sequence has been retrieved. False otherwise.
   180	 */
   181	static bool indices_sequence_should_stop(const struct papr_rtas_sequence *seq)
   182	{
   183		struct rtas_get_indices_params *param;
   184		bool done;
   185	
   186		if (seq->error)
   187			return true;
   188	
   189		param =  (struct rtas_get_indices_params *)seq->params;
   190	
   191		switch (param->status) {
   192		case RTAS_IBM_GET_INDICES_COMPLETE:
   193			if (param->next == 1)
   194				done = false; /* Initial state. */
   195			else
   196				done = true; /* All data consumed. */
   197			break;
   198		case RTAS_IBM_GET_INDICES_MORE_DATA:
   199			done = false; /* More data available. */
   200			break;
   201		default:
   202			done = true; /* Error encountered. */
   203			break;
   204		}
   205	
   206		return done;
   207	}
   208	
   209	/**
 > 210	 * Work function to be passed to papr_rtas_blob_generate().
   211	 *
   212	 * ibm,get-indices RTAS call fills the work area with the certain
   213	 * format but does not return the bytes written in the buffer. So
   214	 * instead of kernel parsing this work area to determine the buffer
   215	 * length, copy the complete work area (RTAS_GET_INDICES_BUF_SIZE)
   216	 * to the blob and let the user space to obtain the data.
   217	 * Means RTAS_GET_INDICES_BUF_SIZE data will be returned for each
   218	 * read().
   219	 */
   220	

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Re: [PATCH 4/6] powerpc/pseries: Add ibm,set-dynamic-indicator RTAS call support

[Dan Carpenter]

Hi Haren,

kernel test robot noticed the following build warnings:

https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Haren-Myneni/powerpc-pseries-Define-common-functions-for-RTAS-sequence-HCALLs/20250105-045010
base:   https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git next
patch link:    https://lore.kernel.org/r/20250104204652.388720-5-haren%40linux.ibm.com
patch subject: [PATCH 4/6] powerpc/pseries: Add ibm,set-dynamic-indicator RTAS call support
config: powerpc64-randconfig-r071-20250108 (https://download.01.org/0day-ci/archive/20250109/202501090337.xKCGrblc-lkp@intel.com/config)
compiler: clang version 20.0.0git (https://github.com/llvm/llvm-project 096551537b2a747a3387726ca618ceeb3950e9bc)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
| Closes: https://lore.kernel.org/r/202501090337.xKCGrblc-lkp@intel.com/

smatch warnings:
arch/powerpc/platforms/pseries/papr-indices.c:438 papr_dynamic_indicator_ioc_set() warn: inconsistent returns 'global &rtas_ibm_set_dynamic_indicator_lock'.

vim +438 arch/powerpc/platforms/pseries/papr-indices.c

3f48afd07934e4 Haren Myneni 2025-01-04  397  static long papr_dynamic_indicator_ioc_set(struct papr_indices_io_block __user *ubuf)
3f48afd07934e4 Haren Myneni 2025-01-04  398  {
3f48afd07934e4 Haren Myneni 2025-01-04  399  	struct papr_indices_io_block kbuf;
3f48afd07934e4 Haren Myneni 2025-01-04  400  	struct rtas_work_area *work_area;
3f48afd07934e4 Haren Myneni 2025-01-04  401  	s32 fwrc, token, ret;
3f48afd07934e4 Haren Myneni 2025-01-04  402  
3f48afd07934e4 Haren Myneni 2025-01-04  403  	token = rtas_function_token(RTAS_FN_IBM_SET_DYNAMIC_INDICATOR);
3f48afd07934e4 Haren Myneni 2025-01-04  404  	if (token == RTAS_UNKNOWN_SERVICE)
3f48afd07934e4 Haren Myneni 2025-01-04  405  		return -ENOENT;
3f48afd07934e4 Haren Myneni 2025-01-04  406  
3f48afd07934e4 Haren Myneni 2025-01-04  407  	mutex_lock(&rtas_ibm_set_dynamic_indicator_lock);
3f48afd07934e4 Haren Myneni 2025-01-04  408  	work_area = papr_dynamic_indice_buf_from_user(ubuf, &kbuf);
3f48afd07934e4 Haren Myneni 2025-01-04  409  	if (IS_ERR(work_area))
3f48afd07934e4 Haren Myneni 2025-01-04  410  		return PTR_ERR(work_area);

mutex_unlock(&rtas_ibm_set_dynamic_indicator_lock); before returning

3f48afd07934e4 Haren Myneni 2025-01-04  411  
3f48afd07934e4 Haren Myneni 2025-01-04  412  	do {
3f48afd07934e4 Haren Myneni 2025-01-04  413  		fwrc = rtas_call(token, 3, 1, NULL,
3f48afd07934e4 Haren Myneni 2025-01-04  414  				kbuf.dynamic_param.token,
3f48afd07934e4 Haren Myneni 2025-01-04  415  				kbuf.dynamic_param.state,
3f48afd07934e4 Haren Myneni 2025-01-04  416  				rtas_work_area_phys(work_area));
3f48afd07934e4 Haren Myneni 2025-01-04  417  	} while (rtas_busy_delay(fwrc));
3f48afd07934e4 Haren Myneni 2025-01-04  418  
3f48afd07934e4 Haren Myneni 2025-01-04  419  	rtas_work_area_free(work_area);
3f48afd07934e4 Haren Myneni 2025-01-04  420  	mutex_unlock(&rtas_ibm_set_dynamic_indicator_lock);
3f48afd07934e4 Haren Myneni 2025-01-04  421  
3f48afd07934e4 Haren Myneni 2025-01-04  422  	switch (fwrc) {
3f48afd07934e4 Haren Myneni 2025-01-04  423  	case RTAS_IBM_DYNAMIC_INDICE_SUCCESS:
3f48afd07934e4 Haren Myneni 2025-01-04  424  		ret = 0;
3f48afd07934e4 Haren Myneni 2025-01-04  425  		break;
3f48afd07934e4 Haren Myneni 2025-01-04  426  	case RTAS_IBM_DYNAMIC_INDICE_NO_INDICATOR:	/* No such indicator */
3f48afd07934e4 Haren Myneni 2025-01-04  427  		ret = -EOPNOTSUPP;
3f48afd07934e4 Haren Myneni 2025-01-04  428  		break;
3f48afd07934e4 Haren Myneni 2025-01-04  429  	default:
3f48afd07934e4 Haren Myneni 2025-01-04  430  		pr_err("unexpected ibm,set-dynamic-indicator result %d\n",
3f48afd07934e4 Haren Myneni 2025-01-04  431  			fwrc);
3f48afd07934e4 Haren Myneni 2025-01-04  432  		fallthrough;
3f48afd07934e4 Haren Myneni 2025-01-04  433  	case RTAS_IBM_DYNAMIC_INDICE_HW_ERROR:	/* Hardware/platform error */
3f48afd07934e4 Haren Myneni 2025-01-04  434  		ret = -EIO;
3f48afd07934e4 Haren Myneni 2025-01-04  435  		break;
3f48afd07934e4 Haren Myneni 2025-01-04  436  	}
3f48afd07934e4 Haren Myneni 2025-01-04  437  
3f48afd07934e4 Haren Myneni 2025-01-04 @438  	return ret;
3f48afd07934e4 Haren Myneni 2025-01-04  439  }

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Re: [PATCH 5/6] powerpc/pseries: Add ibm,get-dynamic-sensor-state RTAS call support

[Dan Carpenter]

Hi Haren,

kernel test robot noticed the following build warnings:

https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Haren-Myneni/powerpc-pseries-Define-common-functions-for-RTAS-sequence-HCALLs/20250105-045010
base:   https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git next
patch link:    https://lore.kernel.org/r/20250104204652.388720-6-haren%40linux.ibm.com
patch subject: [PATCH 5/6] powerpc/pseries: Add ibm,get-dynamic-sensor-state RTAS call support
config: powerpc64-randconfig-r071-20250108 (https://download.01.org/0day-ci/archive/20250109/202501090552.UzEfb4QU-lkp@intel.com/config)
compiler: clang version 20.0.0git (https://github.com/llvm/llvm-project 096551537b2a747a3387726ca618ceeb3950e9bc)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
| Closes: https://lore.kernel.org/r/202501090552.UzEfb4QU-lkp@intel.com/

New smatch warnings:
arch/powerpc/platforms/pseries/papr-indices.c:496 papr_dynamic_sensor_ioc_get() warn: inconsistent returns 'global &rtas_ibm_get_dynamic_sensor_state_lock'.

Old smatch warnings:
arch/powerpc/platforms/pseries/papr-indices.c:438 papr_dynamic_indicator_ioc_set() warn: inconsistent returns 'global &rtas_ibm_set_dynamic_indicator_lock'.

vim +496 arch/powerpc/platforms/pseries/papr-indices.c

e44fb25ad9fa03 Haren Myneni 2025-01-04  452  static long papr_dynamic_sensor_ioc_get(struct papr_indices_io_block __user *ubuf)
e44fb25ad9fa03 Haren Myneni 2025-01-04  453  {
e44fb25ad9fa03 Haren Myneni 2025-01-04  454  	struct papr_indices_io_block kbuf;
e44fb25ad9fa03 Haren Myneni 2025-01-04  455  	struct rtas_work_area *work_area;
e44fb25ad9fa03 Haren Myneni 2025-01-04  456  	s32 fwrc, token, ret;
e44fb25ad9fa03 Haren Myneni 2025-01-04  457  	u32 rets;
e44fb25ad9fa03 Haren Myneni 2025-01-04  458  
e44fb25ad9fa03 Haren Myneni 2025-01-04  459  	token = rtas_function_token(RTAS_FN_IBM_GET_DYNAMIC_SENSOR_STATE);
e44fb25ad9fa03 Haren Myneni 2025-01-04  460  	if (token == RTAS_UNKNOWN_SERVICE)
e44fb25ad9fa03 Haren Myneni 2025-01-04  461  		return -ENOENT;
e44fb25ad9fa03 Haren Myneni 2025-01-04  462  
e44fb25ad9fa03 Haren Myneni 2025-01-04  463  	mutex_lock(&rtas_ibm_get_dynamic_sensor_state_lock);
e44fb25ad9fa03 Haren Myneni 2025-01-04  464  	work_area = papr_dynamic_indice_buf_from_user(ubuf, &kbuf);
e44fb25ad9fa03 Haren Myneni 2025-01-04  465  	if (IS_ERR(work_area))
e44fb25ad9fa03 Haren Myneni 2025-01-04  466  		return PTR_ERR(work_area);

Add an unlock, same as with the _set() function.

e44fb25ad9fa03 Haren Myneni 2025-01-04  467  
e44fb25ad9fa03 Haren Myneni 2025-01-04  468  	do {
e44fb25ad9fa03 Haren Myneni 2025-01-04  469  		fwrc = rtas_call(token, 2, 2, &rets,
e44fb25ad9fa03 Haren Myneni 2025-01-04  470  				kbuf.dynamic_param.token,
e44fb25ad9fa03 Haren Myneni 2025-01-04  471  				rtas_work_area_phys(work_area));
e44fb25ad9fa03 Haren Myneni 2025-01-04  472  	} while (rtas_busy_delay(fwrc));
e44fb25ad9fa03 Haren Myneni 2025-01-04  473  
e44fb25ad9fa03 Haren Myneni 2025-01-04  474  	rtas_work_area_free(work_area);
e44fb25ad9fa03 Haren Myneni 2025-01-04  475  	mutex_unlock(&rtas_ibm_get_dynamic_sensor_state_lock);
e44fb25ad9fa03 Haren Myneni 2025-01-04  476  
e44fb25ad9fa03 Haren Myneni 2025-01-04  477  	switch (fwrc) {
e44fb25ad9fa03 Haren Myneni 2025-01-04  478  	case RTAS_IBM_DYNAMIC_INDICE_SUCCESS:
e44fb25ad9fa03 Haren Myneni 2025-01-04  479  		if (put_user(rets, &ubuf->dynamic_param.state))
e44fb25ad9fa03 Haren Myneni 2025-01-04  480  			ret = -EFAULT;
e44fb25ad9fa03 Haren Myneni 2025-01-04  481  		else
e44fb25ad9fa03 Haren Myneni 2025-01-04  482  			ret = 0;
e44fb25ad9fa03 Haren Myneni 2025-01-04  483  		break;
e44fb25ad9fa03 Haren Myneni 2025-01-04  484  	case RTAS_IBM_DYNAMIC_INDICE_NO_INDICATOR:	/* No such indicator */
e44fb25ad9fa03 Haren Myneni 2025-01-04  485  		ret = -EOPNOTSUPP;
e44fb25ad9fa03 Haren Myneni 2025-01-04  486  		break;
e44fb25ad9fa03 Haren Myneni 2025-01-04  487  	default:
e44fb25ad9fa03 Haren Myneni 2025-01-04  488  		pr_err("unexpected ibm,get-dynamic-sensor result %d\n",
e44fb25ad9fa03 Haren Myneni 2025-01-04  489  				fwrc);
e44fb25ad9fa03 Haren Myneni 2025-01-04  490  		fallthrough;
e44fb25ad9fa03 Haren Myneni 2025-01-04  491  	case RTAS_IBM_DYNAMIC_INDICE_HW_ERROR:	/* Hardware/platform error */
e44fb25ad9fa03 Haren Myneni 2025-01-04  492  		ret = -EIO;
e44fb25ad9fa03 Haren Myneni 2025-01-04  493  		break;
e44fb25ad9fa03 Haren Myneni 2025-01-04  494  	}
e44fb25ad9fa03 Haren Myneni 2025-01-04  495  
e44fb25ad9fa03 Haren Myneni 2025-01-04 @496  	return ret;
e44fb25ad9fa03 Haren Myneni 2025-01-04  497  }

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki