new file mode 100644
@@ -0,0 +1,210 @@
+Oracle Data Analytics Accelerator (DAX)
+---------------------------------------
+
+DAX is a coprocessor which resides on the SPARC M7 (DAX1) and M8
+(DAX2) processor chips, and has direct access to the CPU's L3 caches
+as well as physical memory. It can perform several operations on data
+streams with various input and output formats. A driver provides a
+transport mechanism and does not have knowledge of the various opcodes
+and data formats. A user space library (insert link here) provides
+high level services and translates these into low level commands which
+are then passed into the driver and subsequently the Hypervisor and
+the coprocessor. The library is the recommended way for applications
+to use the coprocessor, and the driver interface is not intended for
+general use. This document describes the general flow of the driver,
+its structures, and its programmatic interface.
+
+
+High Level Overview
+-------------------
+
+A coprocessor request is described by a Command Control Block
+(CCB). The CCB contains an opcode and various parameters. The opcode
+specifies what operation is to be done, and the parameters specify
+options, flags, sizes, and addresses. The CCB (or an array of CCBs)
+is passed to the Hypervisor, which handles queueing and scheduling of
+requests to the available coprocessor execution units. A status code
+returned indicates if the request was submitted successfully or if
+there was an error. One of the addresses given in each CCB is a
+pointer to a "completion area", which is a 128 byte memory block that
+is written by the coprocessor to provide execution status. No
+interrupt is generated upon completion; the completion area must be
+polled by software to find out when a transaction has finished, but
+the M7 and later processors provide a mechanism to pause the virtual
+processor until the completion status has been updated by the
+coprocessor. This is done using the monitored load and mwait
+instructions, which are described in more detail later. The DAX
+coprocessor was designed so that after a request is submitted, the
+kernel is no longer involved in the processing of it. The polling is
+done at the user level, which results in almost zero latency between
+completion of a request and resumption of execution of the requesting
+thread.
+
+
+Addressing Memory
+-----------------
+
+The kernel does not have access to physical memory in the Sun4v
+architecture, as there is an additional level of memory virtualization
+present. This intermediate level is called "real" memory, and the
+kernel treats this as if it were physical. The Hypervisor handles the
+translations between real memory and physical so that each logical
+domain (LDOM) can have a partition of physical memory that is isolated
+from that of other LDOMs. When the kernel sets up a virtual mapping,
+it specifies a virtual address and the real address to which it should
+be mapped.
+
+The DAX coprocessor can only operate on physical memory, so before a
+request can be fed to the coprocessor, all the addresses in a CCB must
+be converted into physical addresses. The kernel cannot do this since
+it has no visibility into physical addresses. So a CCB may contain
+either the virtual or real addresses of the buffers or a combination
+of them. An "address type" field is available for each address that
+may be given in the CCB. In all cases, the Hypervisor will translate
+all the addresses to physical before dispatching to hardware.
+
+
+The Driver API
+--------------
+
+An application makes requests to the driver via the write() system
+call, and gets results (if any) via read(). The completion areas are
+made accessible via mmap(), and are read-only for the application.
+
+The request may either be an immediate command or an array of CCBs to
+be submitted to the hardware.
+
+Each open instance of the device is exclusive to the thread that
+opened it, and must be used by that thread for all subsequent
+operations. The driver open function creates a new context for the
+thread and initializes it for use. This context contains pointers and
+values used internally by the driver to keep track of submitted
+requests. The completion area buffer is also allocated, and this is
+large enough to contain the completion areas for many concurrent
+requests. When the device is closed, any outstanding transactions are
+flushed and the context is cleaned up.
+
+On a DAX1 system (M7), the device will be called "oradax1", while on a
+DAX2 system (M8) it will be "oradax2". If an application requires one
+or the other, it should simply attempt to open the appropriate
+device. Only one of the devices will exist on any given system, so the
+name can be used to determine what the platform supports.
+
+The immediate commands are CCB_DEQUEUE, CCB_KILL, and CCB_INFO. For
+all of these, success is indicated by a return value from write()
+equal to the number of bytes given in the call. Otherwise -1 is
+returned and errno is set.
+
+CCB_DEQUEUE
+
+Tells the driver to clean up resources associated with past
+requests. Since no interrupt is generated upon the completion of a
+request, the driver must be told when it may reclaim resources. No
+further status information is returned, so the user should not
+subsequently call read().
+
+CCB_KILL
+
+Kills a CCB during execution. The CCB is guaranteed to not continue
+executing once this call returns successfully. On success, read() must
+be called to retrieve the result of the action.
+
+CCB_INFO
+
+Retrieves information about a currently executing CCB. Note that some
+Hypervisors might return 'notfound' when the CCB is in 'inprogress'
+state. To ensure a CCB in the 'notfound' state will never be executed,
+CCB_KILL must be invoked on that CCB. Upon success, read() must be
+called to retrieve the details of the action.
+
+Submission of an array of CCBs for execution
+
+A write() whose length is a multiple of the CCB size is treated as a
+submit operation. The file offset is treated as the index of the
+completion area to use, and may be set via lseek() or using the
+pwrite() system call. If -1 is returned then errno is set to indicate
+the error. Otherwise, the return value is the length of the array that
+was actually accepted by the coprocessor. If the accepted length is
+equal to the requested length, then the operation was completely
+successful and there is no further status needed; hence, the user
+should not subsequently call read(). Partial acceptance of the CCB
+array is indicated by a return value less than the requested length,
+and read() must be called to retrieve further status information. The
+status will reflect the error caused by the first CCB that was not
+accepted, and status_data will provide additional data in some cases.
+
+MMAP
+
+The mmap() function provides access to the completion area allocated
+in the driver. Note that the completion area is not writeable by the
+user process.
+
+
+Completion of a Request
+-----------------------
+
+The first byte in each completion area is the command status which is
+updated by the coprocessor hardware. Software may take advantage of
+new M7/M8 processor capabilities to efficiently poll this status byte.
+First, a "monitored load" is achieved via a Load from Alternate Space
+(ldxa, lduba, etc.) with ASI 0x84 (ASI_MONITOR_PRIMARY). Second, a
+"monitored wait" is achieved via the mwait instruction. This
+instruction is like pause in that it suspends execution of the virtual
+processor, but in addition will terminate early when one of several
+events occur. If the block of data containing the monitored location
+is modified, then the mwait terminates. This allows software to resume
+execution immediately (without a context switch or kernel to user
+transition) after a transaction completes. Thus the latency between
+transaction completion and resumption of execution may be just a few
+nanoseconds.
+
+
+Application Life Cycle of a DAX Submission
+------------------------------------------
+
+ - open dax device
+ - call mmap() to get the completion area address
+ - allocate a CCB and fill in the opcode, flags, parameter, addresses, etc.
+ - submit CCB via write()
+ - go into a loop executing monitored load + monitored wait and
+ terminate when the command status indicates the request is complete
+ (CCB_KILL or CCB_INFO may be used any time as necessary)
+ - perform a CCB_DEQUEUE
+ - call munmap() for completion area
+ - close the dax device
+
+
+Memory Constraints
+------------------
+
+The DAX hardware operates only on physical addresses. Therefore, it is
+not aware of virtual memory mappings and the discontiguities that may
+exist in the physical memory that a virtual buffer maps to. There is
+no I/O TLB or any scatter/gather mechanism. All buffers, whether input
+or output, must reside in a physically contiguous region of memory.
+
+The Hypervisor translates all addresses within a CCB to physical
+before handing off the CCB to DAX. The Hypervisor determines the
+virtual page size for each virtual address given, and uses this to
+program a size limit for each address. This prevents the coprocessor
+from reading or writing beyond the bound of the virtual page, even
+though it is accessing physical memory directly. A simpler way of
+saying this is that a DAX operation will never "cross" a virtual page
+boundary. If an 8k virtual page is used, then the data is strictly
+limited to 8k. If a user's buffer is larger than 8k, then a larger
+page size must be used, or the transaction size will be truncated to
+8k.
+
+Huge pages. A user may allocate huge pages using standard
+interfaces. Memory buffers residing on huge pages may be used to
+achieve much larger DAX transaction sizes, but the rules must still be
+followed, and no transaction will cross a page boundary, even a huge
+page. A major caveat is that Linux on Sparc presents 8Mb as one of
+the huge page sizes. Sparc does not actually provide a 8Mb hardware
+page size, and this size is synthesized by pasting together two 4Mb
+pages. The reasons for this are historical, and it creates an issue
+because only half of this 8Mb page can actually be used for any given
+buffer in a DAX request, and it must be either the first half or the
+second half; it cannot be a 4Mb chunk in the middle, since that
+crosses a (hardware) page boundary. Note that this entire issue may be
+hidden by higher level libraries.
new file mode 100644
@@ -0,0 +1,91 @@
+/*
+ * Copyright (c) 2017, Oracle and/or its affiliates. All rights reserved.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/*
+ * Oracle DAX driver API definitions
+ */
+
+#ifndef _ORADAX_H
+#define _ORADAX_H
+
+#include <linux/types.h>
+
+#define CCB_KILL 0
+#define CCB_INFO 1
+#define CCB_DEQUEUE 2
+
+struct dax_command {
+ __u16 command; /* CCB_KILL/INFO/DEQUEUE */
+ __u16 ca_offset; /* offset into mmapped completion area */
+};
+
+struct ccb_kill_result {
+ __u16 action; /* action taken to kill ccb */
+};
+
+struct ccb_info_result {
+ __u16 state; /* state of enqueued ccb */
+ __u16 inst_num; /* dax instance number of enqueued ccb */
+ __u16 q_num; /* queue number of enqueued ccb */
+ __u16 q_pos; /* ccb position in queue */
+};
+
+struct ccb_exec_result {
+ __u64 status_data; /* additional status data (e.g. bad VA) */
+ __u32 status; /* one of DAX_SUBMIT_* */
+};
+
+union ccb_result {
+ struct ccb_exec_result exec;
+ struct ccb_info_result info;
+ struct ccb_kill_result kill;
+};
+
+#define DAX_MMAP_LEN (16 * 1024)
+#define DAX_MAX_CCBS 15
+#define DAX_CCB_BUF_MAXLEN (DAX_MAX_CCBS * 64)
+#define DAX_NAME "oradax"
+
+/* CCB_EXEC status */
+#define DAX_SUBMIT_OK 0
+#define DAX_SUBMIT_ERR_RETRY 1
+#define DAX_SUBMIT_ERR_WOULDBLOCK 2
+#define DAX_SUBMIT_ERR_BUSY 3
+#define DAX_SUBMIT_ERR_THR_INIT 4
+#define DAX_SUBMIT_ERR_ARG_INVAL 5
+#define DAX_SUBMIT_ERR_CCB_INVAL 6
+#define DAX_SUBMIT_ERR_NO_CA_AVAIL 7
+#define DAX_SUBMIT_ERR_CCB_ARR_MMU_MISS 8
+#define DAX_SUBMIT_ERR_NOMAP 9
+#define DAX_SUBMIT_ERR_NOACCESS 10
+#define DAX_SUBMIT_ERR_TOOMANY 11
+#define DAX_SUBMIT_ERR_UNAVAIL 12
+#define DAX_SUBMIT_ERR_INTERNAL 13
+
+/* CCB_INFO states - must match HV_CCB_STATE_* definitions */
+#define DAX_CCB_COMPLETED 0
+#define DAX_CCB_ENQUEUED 1
+#define DAX_CCB_INPROGRESS 2
+#define DAX_CCB_NOTFOUND 3
+
+/* CCB_KILL actions - must match HV_CCB_KILL_* definitions */
+#define DAX_KILL_COMPLETED 0
+#define DAX_KILL_DEQUEUED 1
+#define DAX_KILL_KILLED 2
+#define DAX_KILL_NOTFOUND 3
+
+#endif /* _ORADAX_H */
@@ -70,5 +70,13 @@ config DISPLAY7SEG
another UltraSPARC-IIi-cEngine boardset with a 7-segment display,
you should say N to this option.
+config ORACLE_DAX
+ tristate "Oracle Data Analytics Accelerator"
+ default m if SPARC64
+ help
+ Driver for Oracle Data Analytics Accelerator, which is
+ a coprocessor that performs database operations in hardware.
+ It is available on M7 and M8 based systems only.
+
endmenu
@@ -16,3 +16,4 @@ obj-$(CONFIG_SUN_OPENPROMIO) += openprom.o
obj-$(CONFIG_TADPOLE_TS102_UCTRL) += uctrl.o
obj-$(CONFIG_SUN_JSFLASH) += jsflash.o
obj-$(CONFIG_BBC_I2C) += bbc.o
+obj-$(CONFIG_ORACLE_DAX) += oradax.o
new file mode 100644
@@ -0,0 +1,951 @@
+/*
+ * Copyright (c) 2017, Oracle and/or its affiliates. All rights reserved.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/*
+ * Oracle Data Analytics Accelerator (DAX)
+ *
+ * DAX is a coprocessor which resides on the SPARC M7 (DAX1) and M8
+ * (DAX2) processor chips, and has direct access to the CPU's L3
+ * caches as well as physical memory. It can perform several
+ * operations on data streams with various input and output formats.
+ * The driver provides a transport mechanism and does not have
+ * knowledge of the various opcodes and data formats. A user space
+ * library provides high level services and translates these into low
+ * level commands which are then passed into the driver and
+ * subsequently the hypervisor and the coprocessor. The library is
+ * the recommended way for applications to use the coprocessor, and
+ * the driver interface is not intended for general use.
+ *
+ * See Documentation/sparc/oracle_dax.txt for more details.
+ */
+
+#include <linux/uaccess.h>
+#include <linux/module.h>
+#include <linux/delay.h>
+#include <linux/cdev.h>
+#include <linux/slab.h>
+#include <linux/mm.h>
+
+#include <asm/hypervisor.h>
+#include <asm/mdesc.h>
+#include <asm/oradax.h>
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Driver for Oracle Data Analytics Accelerator");
+
+#define DAX_DBG_FLG_BASIC 0x01
+#define DAX_DBG_FLG_STAT 0x02
+#define DAX_DBG_FLG_INFO 0x04
+#define DAX_DBG_FLG_ALL 0xff
+
+#define dax_err(fmt, ...) pr_err("%s: " fmt "\n", __func__, ##__VA_ARGS__)
+#define dax_info(fmt, ...) pr_info("%s: " fmt "\n", __func__, ##__VA_ARGS__)
+
+#define dax_dbg(fmt, ...) do { \
+ if (dax_debug & DAX_DBG_FLG_BASIC)\
+ dax_info(fmt, ##__VA_ARGS__); \
+ } while (0)
+#define dax_stat_dbg(fmt, ...) do { \
+ if (dax_debug & DAX_DBG_FLG_STAT) \
+ dax_info(fmt, ##__VA_ARGS__); \
+ } while (0)
+#define dax_info_dbg(fmt, ...) do { \
+ if (dax_debug & DAX_DBG_FLG_INFO) \
+ dax_info(fmt, ##__VA_ARGS__); \
+ } while (0)
+
+#define DAX1_MINOR 1
+#define DAX1_MAJOR 1
+#define DAX2_MINOR 0
+#define DAX2_MAJOR 2
+
+#define DAX1_STR "ORCL,sun4v-dax"
+#define DAX2_STR "ORCL,sun4v-dax2"
+
+#define DAX_CA_ELEMS (DAX_MMAP_LEN / sizeof(struct compl_area))
+
+#define DAX_CCB_USEC 100
+#define DAX_CCB_RETRIES 10000
+
+/* stream types */
+enum {
+ DEST,
+ SRC0,
+ SRC1,
+ TBL,
+ NUM_STREAM_TYPES
+};
+
+/* CCB address types */
+#define CCB_AT_IMM 0 /* immediate */
+#define CCB_AT_VA_ALT 1 /* secondary context */
+#define CCB_AT_RA 2 /* real address */
+#define CCB_AT_VA 3 /* virtual address */
+
+/* CCB dword index values */
+#define CCB_DWORD_CTL 0
+#define CCB_DWORD_COMPL 1
+#define CCB_DWORD_INPUT 2
+#define CCB_DWORD_DAC 3
+#define CCB_DWORD_SEC_INPUT 4
+#define CCB_DWORD_RSVD 5
+#define CCB_DWORD_OUTPUT 6
+#define CCB_DWORD_TBL 7
+#define DWORDS_PER_CCB 8
+
+/* CCB header sync flags */
+#define CCB_SYNC_SERIAL BIT(0)
+#define CCB_SYNC_COND BIT(1)
+#define CCB_SYNC_LONGCCB BIT(2)
+
+/* Completion area cmd_status */
+#define CCB_CMD_STAT_IN_PROGRESS 0
+#define CCB_CMD_STAT_COMPLETED 1
+#define CCB_CMD_STAT_FAILED 2
+#define CCB_CMD_STAT_KILLED 3
+#define CCB_CMD_STAT_NOT_RUN 4
+#define CCB_CMD_STAT_NO_OUTPUT 5
+#define CCB_CMD_STAT_PIPE_ERR_SRC 6
+#define CCB_CMD_STAT_PIPE_ERR_DST 7
+
+/* Completion area err_mask of user visible errors */
+#define CCB_CMD_ERR_BOF 0x1 /* buffer overflow */
+#define CCB_CMD_ERR_DECODE 0x2 /* CCB decode error */
+#define CCB_CMD_ERR_POF 0x3 /* page overflow */
+#define CCB_CMD_ERR_KILL 0x7 /* command was killed */
+#define CCB_CMD_ERR_TO 0x8 /* command timeout */
+#define CCB_CMD_ERR_MCD 0x9 /* MCD error */
+#define CCB_CMD_ERR_DATA_FMT 0xA /* data format error */
+#define CCB_CMD_ERR_NO_RETRY 0xE /* other error, don't retry */
+#define CCB_CMD_ERR_RETRY 0xF /* other error, do retry */
+#define CCB_CMD_ERR_PARTIAL_SYM 0x80 /* partial symbol warning */
+
+#define IS_LONG_CCB(ccb) \
+ ((ccb)->hdr.sync_flags & CCB_SYNC_LONGCCB)
+
+struct ccb_hdr {
+ u32 rsvd:4;
+ u32 sync_flags:4;
+ u32 rsvd2:11;
+ /* use CCB_AT_* macros for at_* fields */
+ u32 at_tbl:2;
+ u32 at_dst:3;
+ u32 at_src1:3;
+ u32 at_src0:3;
+ u32 at_cmpl:2;
+};
+
+union ccb {
+ u64 dwords[DWORDS_PER_CCB];
+ struct ccb_hdr hdr;
+};
+
+struct compl_area {
+ u8 cmd_status; /* user may mwait on this address */
+ u8 err_mask; /* user visible error notification */
+ u8 rsvd[2]; /* reserved */
+ u32 rsvd2; /* reserved */
+ u32 output_sz; /* Bytes of output */
+ u32 rsvd3; /* reserved */
+ u64 run_time; /* run time in OCND2 cycles */
+ u64 run_stats; /* nothing reported for DAX1 nor in DAX2 */
+ u32 n_processed; /* input elements processed */
+ u32 rsvd4[5]; /* reserved */
+ u64 command_rv; /* command return value */
+ u64 rsvd5[8]; /* reserved */
+};
+
+/* per thread CCB context */
+struct dax_ctx {
+ union ccb *ccb_buf;
+ u64 ccb_buf_ra; /* cached RA of ccb_buf */
+ struct compl_area *ca_buf;
+ u64 ca_buf_ra; /* cached RA of ca_buf */
+ struct page *pages[DAX_CA_ELEMS][NUM_STREAM_TYPES];
+ /* array of locked pages */
+ struct task_struct *owner; /* thread that owns ctx */
+ struct task_struct *client; /* requesting thread */
+ union ccb_result result;
+ u32 ccb_count;
+ u32 fail_count;
+};
+
+/* driver public entry points */
+static int dax_open(struct inode *inode, struct file *file);
+static ssize_t dax_read(struct file *filp, char __user *buf,
+ size_t count, loff_t *ppos);
+static ssize_t dax_write(struct file *filp, const char __user *buf,
+ size_t count, loff_t *ppos);
+static int dax_devmap(struct file *f, struct vm_area_struct *vma);
+static int dax_close(struct inode *i, struct file *f);
+
+static const struct file_operations dax_fops = {
+ .owner = THIS_MODULE,
+ .open = dax_open,
+ .read = dax_read,
+ .write = dax_write,
+ .mmap = dax_devmap,
+ .release = dax_close,
+};
+
+static int dax_ccb_exec(struct dax_ctx *ctx, const char __user *buf,
+ size_t count, loff_t *ppos);
+static int dax_ccb_info(u64 ca, struct ccb_info_result *info);
+static int dax_ccb_kill(u64 ca, u16 *kill_res);
+
+static struct cdev c_dev;
+static struct class *cl;
+static dev_t first;
+
+static int dax_debug;
+module_param(dax_debug, int, 0644);
+MODULE_PARM_DESC(dax_debug, "Debug flags");
+
+static int __init dax_attach(void)
+{
+ unsigned long dummy, hv_rv, major, minor, minor_requested, max_ccbs;
+ struct mdesc_handle *hp = mdesc_grab();
+ char *prop, *dax_name;
+ bool found = false;
+ int len, ret = 0;
+ u64 pn;
+
+ if (hp == NULL) {
+ dax_err("Unable to grab mdesc");
+ return -ENODEV;
+ }
+
+ mdesc_for_each_node_by_name(hp, pn, "virtual-device") {
+ prop = (char *)mdesc_get_property(hp, pn, "name", &len);
+ if (prop == NULL)
+ continue;
+ if (strncmp(prop, "dax", strlen("dax")))
+ continue;
+ dax_dbg("Found node 0x%llx = %s", pn, prop);
+
+ prop = (char *)mdesc_get_property(hp, pn, "compatible", &len);
+ if (prop == NULL)
+ continue;
+ dax_dbg("Found node 0x%llx = %s", pn, prop);
+ found = true;
+ break;
+ }
+
+ if (!found) {
+ dax_err("No DAX device found");
+ ret = -ENODEV;
+ goto done;
+ }
+
+ if (strncmp(prop, DAX2_STR, strlen(DAX2_STR)) == 0) {
+ dax_name = DAX_NAME "2";
+ major = DAX2_MAJOR;
+ minor_requested = DAX2_MINOR;
+ dax_dbg("MD indicates DAX2 coprocessor");
+ } else if (strncmp(prop, DAX1_STR, strlen(DAX1_STR)) == 0) {
+ dax_name = DAX_NAME "1";
+ major = DAX1_MAJOR;
+ minor_requested = DAX1_MINOR;
+ dax_dbg("MD indicates DAX1 coprocessor");
+ } else {
+ dax_err("Unknown dax type: %s", prop);
+ ret = -ENODEV;
+ goto done;
+ }
+
+ minor = minor_requested;
+ dax_dbg("Registering DAX HV api with major %ld minor %ld", major,
+ minor);
+ if (sun4v_hvapi_register(HV_GRP_DAX, major, &minor)) {
+ dax_err("hvapi_register failed");
+ ret = -ENODEV;
+ goto done;
+ } else {
+ dax_dbg("Max minor supported by HV = %ld (major %ld)", minor,
+ major);
+ minor = min(minor, minor_requested);
+ dax_dbg("registered DAX major %ld minor %ld", major, minor);
+ }
+
+ /* submit a zero length ccb array to query coprocessor queue size */
+ hv_rv = sun4v_ccb_submit(0, 0, HV_CCB_QUERY_CMD, 0, &max_ccbs, &dummy);
+ if (hv_rv != 0) {
+ dax_err("get_hwqueue_size failed with status=%ld and max_ccbs=%ld",
+ hv_rv, max_ccbs);
+ ret = -ENODEV;
+ goto done;
+ }
+
+ if (max_ccbs != DAX_MAX_CCBS) {
+ dax_err("HV reports unsupported max_ccbs=%ld", max_ccbs);
+ ret = -ENODEV;
+ goto done;
+ }
+
+ if (alloc_chrdev_region(&first, 0, 1, DAX_NAME) < 0) {
+ dax_err("alloc_chrdev_region failed");
+ ret = -ENXIO;
+ goto done;
+ }
+
+ cl = class_create(THIS_MODULE, DAX_NAME);
+ if (cl == NULL) {
+ dax_err("class_create failed");
+ ret = -ENXIO;
+ goto class_error;
+ }
+
+ if (device_create(cl, NULL, first, NULL, dax_name) == NULL) {
+ dax_err("device_create failed");
+ ret = -ENXIO;
+ goto device_error;
+ }
+
+ cdev_init(&c_dev, &dax_fops);
+ if (cdev_add(&c_dev, first, 1) == -1) {
+ dax_err("cdev_add failed");
+ ret = -ENXIO;
+ goto cdev_error;
+ }
+
+ pr_info("Attached DAX module\n");
+ goto done;
+
+cdev_error:
+ device_destroy(cl, first);
+device_error:
+ class_destroy(cl);
+class_error:
+ unregister_chrdev_region(first, 1);
+done:
+ mdesc_release(hp);
+ return ret;
+}
+module_init(dax_attach);
+
+static void __exit dax_detach(void)
+{
+ pr_info("Cleaning up DAX module\n");
+ cdev_del(&c_dev);
+ device_destroy(cl, first);
+ class_destroy(cl);
+ unregister_chrdev_region(first, 1);
+}
+module_exit(dax_detach);
+
+/* map completion area */
+static int dax_devmap(struct file *f, struct vm_area_struct *vma)
+{
+ struct dax_ctx *ctx = (struct dax_ctx *)f->private_data;
+ size_t len = vma->vm_end - vma->vm_start;
+
+ dax_dbg("len=0x%lx, flags=0x%lx", len, vma->vm_flags);
+
+ if (ctx->owner != current) {
+ dax_dbg("devmap called from wrong thread");
+ return -EINVAL;
+ }
+
+ if (len != DAX_MMAP_LEN) {
+ dax_dbg("len(%lu) != DAX_MMAP_LEN(%d)", len, DAX_MMAP_LEN);
+ return -EINVAL;
+ }
+
+ /* completion area is mapped read-only for user */
+ if (vma->vm_flags & VM_WRITE)
+ return -EPERM;
+ vma->vm_flags &= ~VM_MAYWRITE;
+
+ if (remap_pfn_range(vma, vma->vm_start, ctx->ca_buf_ra >> PAGE_SHIFT,
+ len, vma->vm_page_prot))
+ return -EAGAIN;
+
+ dax_dbg("mmapped completion area at uva 0x%lx", vma->vm_start);
+ return 0;
+}
+
+/* Unlock user pages. Called during dequeue or device close */
+static void dax_unlock_pages(struct dax_ctx *ctx, int ccb_index, int nelem)
+{
+ int i, j;
+
+ for (i = ccb_index; i < ccb_index + nelem; i++) {
+ for (j = 0; j < NUM_STREAM_TYPES; j++) {
+ struct page *p = ctx->pages[i][j];
+
+ if (p) {
+ dax_dbg("freeing page %p", p);
+ if (j == DEST)
+ set_page_dirty(p);
+ put_page(p);
+ ctx->pages[i][j] = NULL;
+ }
+ }
+ }
+}
+
+static int dax_lock_page(unsigned long va, struct page **p)
+{
+ int ret;
+
+ dax_dbg("uva 0x%lx", va);
+
+ ret = get_user_pages_fast(va, 1, 1, p);
+ if (ret == 1) {
+ dax_dbg("locked page %p, for VA 0x%lx", *p, va);
+ return 0;
+ }
+
+ dax_dbg("get_user_pages failed, va=0x%lx, ret=%d", va, ret);
+ return -1;
+}
+
+static int dax_lock_pages(struct dax_ctx *ctx, int idx,
+ int nelem, u64 *err_va)
+{
+ int i;
+
+ for (i = 0; i < nelem; i++) {
+ union ccb *ccbp = &ctx->ccb_buf[i];
+
+ /*
+ * For each address in the CCB whose type is virtual,
+ * lock the page and change the type to virtual alternate
+ * context. On error, return the offending address in
+ * err_va.
+ */
+ if (ccbp->hdr.at_dst == CCB_AT_VA) {
+ dax_dbg("output");
+ if (dax_lock_page(ccbp->dwords[CCB_DWORD_OUTPUT],
+ &ctx->pages[i + idx][DEST]) != 0) {
+ *err_va = ccbp->dwords[CCB_DWORD_OUTPUT];
+ goto error;
+ }
+ ccbp->hdr.at_dst = CCB_AT_VA_ALT;
+ }
+
+ if (ccbp->hdr.at_src0 == CCB_AT_VA) {
+ dax_dbg("input");
+ if (dax_lock_page(ccbp->dwords[CCB_DWORD_INPUT],
+ &ctx->pages[i + idx][SRC0]) != 0) {
+ *err_va = ccbp->dwords[CCB_DWORD_INPUT];
+ goto error;
+ }
+ ccbp->hdr.at_src0 = CCB_AT_VA_ALT;
+ }
+
+ if (ccbp->hdr.at_src1 == CCB_AT_VA) {
+ dax_dbg("sec input");
+ if (dax_lock_page(ccbp->dwords[CCB_DWORD_SEC_INPUT],
+ &ctx->pages[i + idx][SRC1]) != 0) {
+ *err_va = ccbp->dwords[CCB_DWORD_SEC_INPUT];
+ goto error;
+ }
+ ccbp->hdr.at_src1 = CCB_AT_VA_ALT;
+ }
+
+ if (ccbp->hdr.at_tbl == CCB_AT_VA) {
+ dax_dbg("tbl");
+ if (dax_lock_page(ccbp->dwords[CCB_DWORD_TBL],
+ &ctx->pages[i + idx][TBL]) != 0) {
+ *err_va = ccbp->dwords[CCB_DWORD_TBL];
+ goto error;
+ }
+ ccbp->hdr.at_tbl = CCB_AT_VA_ALT;
+ }
+
+ /* skip over 2nd 64 bytes of long CCB */
+ if (IS_LONG_CCB(ccbp))
+ i++;
+ }
+ return DAX_SUBMIT_OK;
+
+error:
+ dax_unlock_pages(ctx, idx, nelem);
+ return DAX_SUBMIT_ERR_NOACCESS;
+}
+
+static void dax_ccb_wait(struct dax_ctx *ctx, int idx)
+{
+ int ret, nretries;
+ u16 kill_res;
+
+ dax_dbg("idx=%d", idx);
+
+ for (nretries = 0; nretries < DAX_CCB_RETRIES; nretries++) {
+ if (ctx->ca_buf[idx].cmd_status == CCB_CMD_STAT_IN_PROGRESS)
+ udelay(DAX_CCB_USEC);
+ else
+ return;
+ }
+ dax_dbg("ctx (%p): CCB[%d] timed out, wait usec=%d, retries=%d. Killing ccb",
+ (void *)ctx, idx, DAX_CCB_USEC, DAX_CCB_RETRIES);
+
+ ret = dax_ccb_kill(ctx->ca_buf_ra + idx * sizeof(struct compl_area),
+ &kill_res);
+ dax_dbg("Kill CCB[%d] %s", idx, ret ? "failed" : "succeeded");
+}
+
+static int dax_close(struct inode *ino, struct file *f)
+{
+ struct dax_ctx *ctx = (struct dax_ctx *)f->private_data;
+ int i;
+
+ f->private_data = NULL;
+
+ for (i = 0; i < DAX_CA_ELEMS; i++) {
+ if (ctx->ca_buf[i].cmd_status == CCB_CMD_STAT_IN_PROGRESS) {
+ dax_dbg("CCB[%d] not completed", i);
+ dax_ccb_wait(ctx, i);
+ }
+ dax_unlock_pages(ctx, i, 1);
+ }
+
+ kfree(ctx->ccb_buf);
+ kfree(ctx->ca_buf);
+ dax_stat_dbg("CCBs: %d good, %d bad", ctx->ccb_count, ctx->fail_count);
+ kfree(ctx);
+
+ return 0;
+}
+
+static ssize_t dax_read(struct file *f, char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ struct dax_ctx *ctx = f->private_data;
+
+ if (ctx->client != current)
+ return -EUSERS;
+
+ ctx->client = NULL;
+
+ if (count != sizeof(union ccb_result))
+ return -EINVAL;
+ if (copy_to_user(buf, &ctx->result, sizeof(union ccb_result)))
+ return -EFAULT;
+ return count;
+}
+
+static ssize_t dax_write(struct file *f, const char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ struct dax_ctx *ctx = f->private_data;
+ struct dax_command hdr;
+ unsigned long ca;
+ int i, idx, ret;
+
+ if (ctx->client != NULL)
+ return -EINVAL;
+
+ if (count == 0 || count > DAX_MAX_CCBS * sizeof(union ccb))
+ return -EINVAL;
+
+ if (count % sizeof(union ccb) == 0)
+ return dax_ccb_exec(ctx, buf, count, ppos); /* CCB EXEC */
+
+ if (count != sizeof(struct dax_command))
+ return -EINVAL;
+
+ /* immediate command */
+ if (ctx->owner != current)
+ return -EUSERS;
+
+ if (copy_from_user(&hdr, buf, sizeof(hdr)))
+ return -EFAULT;
+
+ ca = ctx->ca_buf_ra + hdr.ca_offset;
+
+ switch (hdr.command) {
+ case CCB_KILL:
+ if (hdr.ca_offset >= DAX_MMAP_LEN) {
+ dax_dbg("invalid ca_offset (%d) >= ca_buflen (%d)",
+ hdr.ca_offset, DAX_MMAP_LEN);
+ return -EINVAL;
+ }
+
+ ret = dax_ccb_kill(ca, &ctx->result.kill.action);
+ if (ret != 0) {
+ dax_dbg("dax_ccb_kill failed (ret=%d)", ret);
+ return ret;
+ }
+
+ dax_info_dbg("killed (ca_offset %d)", hdr.ca_offset);
+ idx = hdr.ca_offset / sizeof(struct compl_area);
+ ctx->ca_buf[idx].cmd_status = CCB_CMD_STAT_KILLED;
+ ctx->ca_buf[idx].err_mask = CCB_CMD_ERR_KILL;
+ ctx->client = current;
+ return count;
+
+ case CCB_INFO:
+ if (hdr.ca_offset >= DAX_MMAP_LEN) {
+ dax_dbg("invalid ca_offset (%d) >= ca_buflen (%d)",
+ hdr.ca_offset, DAX_MMAP_LEN);
+ return -EINVAL;
+ }
+
+ ret = dax_ccb_info(ca, &ctx->result.info);
+ if (ret != 0) {
+ dax_dbg("dax_ccb_info failed (ret=%d)", ret);
+ return ret;
+ }
+
+ dax_info_dbg("info succeeded on ca_offset %d", hdr.ca_offset);
+ ctx->client = current;
+ return count;
+
+ case CCB_DEQUEUE:
+ for (i = 0; i < DAX_CA_ELEMS; i++) {
+ if (ctx->ca_buf[i].cmd_status !=
+ CCB_CMD_STAT_IN_PROGRESS)
+ dax_unlock_pages(ctx, i, 1);
+ }
+ return count;
+
+ default:
+ return -EINVAL;
+ }
+}
+
+static int dax_open(struct inode *inode, struct file *f)
+{
+ struct dax_ctx *ctx = NULL;
+ int i;
+
+ ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
+ if (ctx == NULL)
+ goto done;
+
+ ctx->ccb_buf = kcalloc(DAX_MAX_CCBS, sizeof(union ccb), GFP_KERNEL);
+ if (ctx->ccb_buf == NULL)
+ goto done;
+
+ ctx->ccb_buf_ra = virt_to_phys(ctx->ccb_buf);
+ dax_dbg("ctx->ccb_buf=0x%p, ccb_buf_ra=0x%llx",
+ (void *)ctx->ccb_buf, ctx->ccb_buf_ra);
+
+ /* allocate CCB completion area buffer */
+ ctx->ca_buf = kzalloc(DAX_MMAP_LEN, GFP_KERNEL);
+ if (ctx->ca_buf == NULL)
+ goto alloc_error;
+ for (i = 0; i < DAX_CA_ELEMS; i++)
+ ctx->ca_buf[i].cmd_status = CCB_CMD_STAT_COMPLETED;
+
+ ctx->ca_buf_ra = virt_to_phys(ctx->ca_buf);
+ dax_dbg("ctx=0x%p, ctx->ca_buf=0x%p, ca_buf_ra=0x%llx",
+ (void *)ctx, (void *)ctx->ca_buf, ctx->ca_buf_ra);
+
+ ctx->owner = current;
+ f->private_data = ctx;
+ return 0;
+
+alloc_error:
+ kfree(ctx->ccb_buf);
+done:
+ if (ctx != NULL)
+ kfree(ctx);
+ return -ENOMEM;
+}
+
+static char *dax_hv_errno(unsigned long hv_ret, int *ret)
+{
+ switch (hv_ret) {
+ case HV_EBADALIGN:
+ *ret = -EFAULT;
+ return "HV_EBADALIGN";
+ case HV_ENORADDR:
+ *ret = -EFAULT;
+ return "HV_ENORADDR";
+ case HV_EINVAL:
+ *ret = -EINVAL;
+ return "HV_EINVAL";
+ case HV_EWOULDBLOCK:
+ *ret = -EAGAIN;
+ return "HV_EWOULDBLOCK";
+ case HV_ENOACCESS:
+ *ret = -EPERM;
+ return "HV_ENOACCESS";
+ default:
+ break;
+ }
+
+ *ret = -EIO;
+ return "UNKNOWN";
+}
+
+static int dax_ccb_kill(u64 ca, u16 *kill_res)
+{
+ unsigned long hv_ret;
+ int count, ret = 0;
+ char *err_str;
+
+ for (count = 0; count < DAX_CCB_RETRIES; count++) {
+ dax_dbg("attempting kill on ca_ra 0x%llx", ca);
+ hv_ret = sun4v_ccb_kill(ca, kill_res);
+
+ if (hv_ret == HV_EOK) {
+ dax_info_dbg("HV_EOK (ca_ra 0x%llx): %d", ca,
+ *kill_res);
+ } else {
+ err_str = dax_hv_errno(hv_ret, &ret);
+ dax_dbg("%s (ca_ra 0x%llx)", err_str, ca);
+ }
+
+ if (ret != -EAGAIN)
+ return ret;
+ dax_info_dbg("ccb_kill count = %d", count);
+ udelay(DAX_CCB_USEC);
+ }
+
+ return -EAGAIN;
+}
+
+static int dax_ccb_info(u64 ca, struct ccb_info_result *info)
+{
+ unsigned long hv_ret;
+ char *err_str;
+ int ret = 0;
+
+ dax_dbg("attempting info on ca_ra 0x%llx", ca);
+ hv_ret = sun4v_ccb_info(ca, info);
+
+ if (hv_ret == HV_EOK) {
+ dax_info_dbg("HV_EOK (ca_ra 0x%llx): %d", ca, info->state);
+ if (info->state == DAX_CCB_ENQUEUED) {
+ dax_info_dbg("dax_unit %d, queue_num %d, queue_pos %d",
+ info->inst_num, info->q_num, info->q_pos);
+ }
+ } else {
+ err_str = dax_hv_errno(hv_ret, &ret);
+ dax_dbg("%s (ca_ra 0x%llx)", err_str, ca);
+ }
+
+ return ret;
+}
+
+static void dax_prt_ccbs(union ccb *ccb, int nelem)
+{
+ int i, j;
+
+ dax_dbg("ccb buffer:");
+ for (i = 0; i < nelem; i++) {
+ dax_dbg(" %sccb[%d]", IS_LONG_CCB(&ccb[i]) ? "long " : "", i);
+ for (j = 0; j < DWORDS_PER_CCB; j++)
+ dax_dbg("\tccb[%d].dwords[%d]=0x%llx",
+ i, j, ccb[i].dwords[j]);
+ }
+}
+
+/*
+ * Validates user CCB content. Also sets completion address and address types
+ * for all addresses contained in CCB.
+ */
+static int dax_preprocess_usr_ccbs(struct dax_ctx *ctx, int idx, int nelem)
+{
+ int i;
+
+ /*
+ * The user is not allowed to specify real address types in
+ * the CCB header. This must be enforced by the kernel before
+ * submitting the CCBs to HV. The only allowed values for all
+ * address fields are VA or IMM
+ */
+ for (i = 0; i < nelem; i++) {
+ union ccb *ccbp = &ctx->ccb_buf[i];
+ unsigned long ca_offset;
+
+ if (ccbp->hdr.at_dst != CCB_AT_VA &&
+ ccbp->hdr.at_dst != CCB_AT_IMM) {
+ dax_dbg("invalid at_dst in user CCB[%d]", i);
+ return DAX_SUBMIT_ERR_CCB_INVAL;
+ }
+
+ if (ccbp->hdr.at_src0 != CCB_AT_VA &&
+ ccbp->hdr.at_src0 != CCB_AT_IMM) {
+ dax_dbg("invalid at_src0 in user CCB[%d]", i);
+ return DAX_SUBMIT_ERR_CCB_INVAL;
+ }
+
+ if (ccbp->hdr.at_src1 != CCB_AT_VA &&
+ ccbp->hdr.at_src1 != CCB_AT_IMM) {
+ dax_dbg("invalid at_src1 in user CCB[%d]", i);
+ return DAX_SUBMIT_ERR_CCB_INVAL;
+ }
+
+ if (ccbp->hdr.at_tbl != CCB_AT_VA &&
+ ccbp->hdr.at_tbl != CCB_AT_IMM) {
+ dax_dbg("invalid at_tbl in user CCB[%d]", i);
+ return DAX_SUBMIT_ERR_CCB_INVAL;
+ }
+
+ /* set completion (real) address and address type */
+ ccbp->hdr.at_cmpl = CCB_AT_RA;
+ ca_offset = (idx + i) * sizeof(struct compl_area);
+ ccbp->dwords[CCB_DWORD_COMPL] = ctx->ca_buf_ra + ca_offset;
+ memset(&ctx->ca_buf[idx + i], 0, sizeof(struct compl_area));
+
+ dax_dbg("ccb[%d]=%p, ca_offset=0x%lx, compl RA=0x%llx",
+ i, ccbp, ca_offset, ctx->ca_buf_ra + ca_offset);
+
+ /* skip over 2nd 64 bytes of long CCB */
+ if (IS_LONG_CCB(ccbp))
+ i++;
+ }
+
+ return DAX_SUBMIT_OK;
+}
+
+static int dax_ccb_exec(struct dax_ctx *ctx, const char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ unsigned long accepted_len, hv_rv;
+ int i, idx, nccbs, naccepted;
+
+ ctx->client = current;
+ idx = *ppos;
+ nccbs = count / sizeof(union ccb);
+
+ if (ctx->owner != current) {
+ dax_dbg("wrong thread");
+ ctx->result.exec.status = DAX_SUBMIT_ERR_THR_INIT;
+ return 0;
+ }
+ dax_dbg("args: ccb_buf_len=%ld, idx=%d", count, idx);
+
+ /* for given index and length, verify ca_buf range exists */
+ if (idx + nccbs >= DAX_CA_ELEMS) {
+ ctx->result.exec.status = DAX_SUBMIT_ERR_NO_CA_AVAIL;
+ return 0;
+ }
+
+ /*
+ * Copy CCBs into kernel buffer to prevent modification by the
+ * user in between validation and submission.
+ */
+ if (copy_from_user(ctx->ccb_buf, buf, count)) {
+ dax_dbg("copyin of user CCB buffer failed");
+ ctx->result.exec.status = DAX_SUBMIT_ERR_CCB_ARR_MMU_MISS;
+ return 0;
+ }
+
+ /* check to see if ca_buf[idx] .. ca_buf[idx + nccbs] are available */
+ for (i = idx; i < idx + nccbs; i++) {
+ if (ctx->ca_buf[i].cmd_status == CCB_CMD_STAT_IN_PROGRESS) {
+ dax_dbg("CA range not available, dequeue needed");
+ ctx->result.exec.status = DAX_SUBMIT_ERR_NO_CA_AVAIL;
+ return 0;
+ }
+ }
+ dax_unlock_pages(ctx, idx, nccbs);
+
+ ctx->result.exec.status = dax_preprocess_usr_ccbs(ctx, idx, nccbs);
+ if (ctx->result.exec.status != DAX_SUBMIT_OK)
+ return 0;
+
+ ctx->result.exec.status = dax_lock_pages(ctx, idx, nccbs,
+ &ctx->result.exec.status_data);
+ if (ctx->result.exec.status != DAX_SUBMIT_OK)
+ return 0;
+
+ if (dax_debug & DAX_DBG_FLG_BASIC)
+ dax_prt_ccbs(ctx->ccb_buf, nccbs);
+
+ hv_rv = sun4v_ccb_submit(ctx->ccb_buf_ra, count,
+ HV_CCB_QUERY_CMD | HV_CCB_VA_SECONDARY, 0,
+ &accepted_len, &ctx->result.exec.status_data);
+
+ switch (hv_rv) {
+ case HV_EOK:
+ /*
+ * Hcall succeeded with no errors but the accepted
+ * length may be less than the requested length. The
+ * only way the driver can resubmit the remainder is
+ * to wait for completion of the submitted CCBs since
+ * there is no way to guarantee the ordering semantics
+ * required by the client applications. Therefore we
+ * let the user library deal with resubmissions.
+ */
+ ctx->result.exec.status = DAX_SUBMIT_OK;
+ break;
+ case HV_EWOULDBLOCK:
+ /*
+ * This is a transient HV API error. The user library
+ * can retry.
+ */
+ dax_dbg("hcall returned HV_EWOULDBLOCK");
+ ctx->result.exec.status = DAX_SUBMIT_ERR_WOULDBLOCK;
+ break;
+ case HV_ENOMAP:
+ /*
+ * HV was unable to translate a VA. The VA it could
+ * not translate is returned in the status_data param.
+ */
+ dax_dbg("hcall returned HV_ENOMAP");
+ ctx->result.exec.status = DAX_SUBMIT_ERR_NOMAP;
+ break;
+ case HV_EINVAL:
+ /*
+ * This is the result of an invalid user CCB as HV is
+ * validating some of the user CCB fields. Pass this
+ * error back to the user. There is no supporting info
+ * to isolate the invalid field.
+ */
+ dax_dbg("hcall returned HV_EINVAL");
+ ctx->result.exec.status = DAX_SUBMIT_ERR_CCB_INVAL;
+ break;
+ case HV_ENOACCESS:
+ /*
+ * HV found a VA that did not have the appropriate
+ * permissions (such as the w bit). The VA in question
+ * is returned in status_data param.
+ */
+ dax_dbg("hcall returned HV_ENOACCESS");
+ ctx->result.exec.status = DAX_SUBMIT_ERR_NOACCESS;
+ break;
+ case HV_EUNAVAILABLE:
+ /*
+ * The requested CCB operation could not be performed
+ * at this time. Return the specific unavailable code
+ * in the status_data field.
+ */
+ dax_dbg("hcall returned HV_EUNAVAILABLE");
+ ctx->result.exec.status = DAX_SUBMIT_ERR_UNAVAIL;
+ break;
+ default:
+ ctx->result.exec.status = DAX_SUBMIT_ERR_INTERNAL;
+ dax_dbg("unknown hcall return value (%ld)", hv_rv);
+ break;
+ }
+
+ /* unlock pages associated with the unaccepted CCBs */
+ naccepted = accepted_len / sizeof(union ccb);
+ dax_unlock_pages(ctx, idx + naccepted, nccbs - naccepted);
+
+ /* mark unaccepted CCBs as not completed */
+ for (i = idx + naccepted; i < idx + nccbs; i++)
+ ctx->ca_buf[i].cmd_status = CCB_CMD_STAT_COMPLETED;
+
+ ctx->ccb_count += naccepted;
+ ctx->fail_count += nccbs - naccepted;
+
+ dax_dbg("hcall rv=%ld, accepted_len=%ld, status_data=0x%llx, ret status=%d",
+ hv_rv, accepted_len, ctx->result.exec.status_data,
+ ctx->result.exec.status);
+
+ if (count == accepted_len)
+ ctx->client = NULL; /* no read needed to complete protocol */
+ return accepted_len;
+}