@@ -351,6 +351,8 @@ Code Seq# Include File Comments
<mailto:mostrows@styx.uwaterloo.ca>
0xB2 00 arch/powerpc/include/uapi/asm/papr-vpd.h powerpc/pseries VPD API
<mailto:linuxppc-dev>
+0xB2 01-02 arch/powerpc/include/uapi/asm/papr-sysparm.h powerpc/pseries system parameter API
+ <mailto:linuxppc-dev>
0xB3 00 linux/mmc/ioctl.h
0xB4 00-0F linux/gpio.h <mailto:linux-gpio@vger.kernel.org>
0xB5 00-0F uapi/linux/rpmsg.h <mailto:linux-remoteproc@vger.kernel.org>
@@ -2,8 +2,10 @@
#ifndef _ASM_POWERPC_PAPR_SYSPARM_H
#define _ASM_POWERPC_PAPR_SYSPARM_H
+#include <uapi/asm/papr-sysparm.h>
+
typedef struct {
- const u32 token;
+ u32 token;
} papr_sysparm_t;
#define mk_papr_sysparm(x_) ((papr_sysparm_t){ .token = x_, })
@@ -20,11 +22,14 @@ typedef struct {
#define PAPR_SYSPARM_TLB_BLOCK_INVALIDATE_ATTRS mk_papr_sysparm(50)
#define PAPR_SYSPARM_LPAR_NAME mk_papr_sysparm(55)
-enum {
- PAPR_SYSPARM_MAX_INPUT = 1024,
- PAPR_SYSPARM_MAX_OUTPUT = 4000,
-};
-
+/**
+ * struct papr_sysparm_buf - RTAS work area layout for system parameter functions.
+ *
+ * This is the memory layout of the buffers passed to/from
+ * ibm,get-system-parameter and ibm,set-system-parameter. It is
+ * distinct from the papr_sysparm_io_block structure that is passed
+ * between user space and the kernel.
+ */
struct papr_sysparm_buf {
__be16 len;
char val[PAPR_SYSPARM_MAX_OUTPUT];
new file mode 100644
@@ -0,0 +1,58 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+#ifndef _UAPI_PAPR_SYSPARM_H_
+#define _UAPI_PAPR_SYSPARM_H_
+
+#include <linux/types.h>
+#include <asm/ioctl.h>
+#include <asm/papr-miscdev.h>
+
+enum {
+ PAPR_SYSPARM_MAX_INPUT = 1024,
+ PAPR_SYSPARM_MAX_OUTPUT = 4000,
+};
+
+struct papr_sysparm_io_block {
+ __u32 parameter;
+ __u16 length;
+ char data[PAPR_SYSPARM_MAX_OUTPUT];
+};
+
+/**
+ * PAPR_SYSPARM_IOC_GET - Retrieve the value of a PAPR system parameter.
+ *
+ * Uses _IOWR because of one corner case: Retrieving the value of the
+ * "OS Service Entitlement Status" parameter (60) requires the caller
+ * to supply input data (a date string) in the buffer passed to
+ * firmware. So the @length and @data of the incoming
+ * papr_sysparm_io_block are always used to initialize the work area
+ * supplied to ibm,get-system-parameter. No other parameters are known
+ * to parameterize the result this way, and callers are encouraged
+ * (but not required) to zero-initialize @length and @data in the
+ * common case.
+ *
+ * On error the contents of the ioblock are indeterminate.
+ *
+ * Return:
+ * 0: Success; @length is the length of valid data in @data, not to exceed @PAPR_SYSPARM_MAX_OUTPUT.
+ * -EIO: Platform error. (-1)
+ * -EINVAL: Incorrect data length or format. (-9999)
+ * -EPERM: The calling partition is not allowed to access this parameter. (-9002)
+ * -EOPNOTSUPP: Parameter not supported on this platform (-3)
+ */
+#define PAPR_SYSPARM_IOC_GET _IOWR(PAPR_MISCDEV_IOC_ID, 1, struct papr_sysparm_io_block)
+
+/**
+ * PAPR_SYSPARM_IOC_SET - Update the value of a PAPR system parameter.
+ *
+ * The contents of the ioblock are unchanged regardless of success.
+ *
+ * Return:
+ * 0: Success; the parameter has been updated.
+ * -EIO: Platform error. (-1)
+ * -EINVAL: Incorrect data length or format. (-9999)
+ * -EPERM: The calling partition is not allowed to access this parameter. (-9002)
+ * -EOPNOTSUPP: Parameter not supported on this platform (-3)
+ */
+#define PAPR_SYSPARM_IOC_SET _IOW(PAPR_MISCDEV_IOC_ID, 2, struct papr_sysparm_io_block)
+
+#endif /* _UAPI_PAPR_SYSPARM_H_ */
@@ -2,14 +2,20 @@
#define pr_fmt(fmt) "papr-sysparm: " fmt
+#include <linux/anon_inodes.h>
#include <linux/bug.h>
+#include <linux/file.h>
+#include <linux/fs.h>
#include <linux/init.h>
#include <linux/kernel.h>
+#include <linux/miscdevice.h>
#include <linux/printk.h>
#include <linux/slab.h>
-#include <asm/rtas.h>
+#include <linux/uaccess.h>
+#include <asm/machdep.h>
#include <asm/papr-sysparm.h>
#include <asm/rtas-work-area.h>
+#include <asm/rtas.h>
struct papr_sysparm_buf *papr_sysparm_buf_alloc(void)
{
@@ -87,7 +93,6 @@ static bool papr_sysparm_buf_can_submit(const struct papr_sysparm_buf *buf)
*
* Return: 0 on success, -errno otherwise. @buf is unmodified on error.
*/
-
int papr_sysparm_get(papr_sysparm_t param, struct papr_sysparm_buf *buf)
{
const s32 token = rtas_function_token(RTAS_FN_IBM_GET_SYSTEM_PARAMETER);
@@ -196,3 +201,152 @@ int papr_sysparm_set(papr_sysparm_t param, const struct papr_sysparm_buf *buf)
return ret;
}
+
+static struct papr_sysparm_buf *
+papr_sysparm_buf_from_user(const struct papr_sysparm_io_block __user *user_iob)
+{
+ struct papr_sysparm_buf *kern_spbuf;
+ long err;
+ u16 len;
+
+ /*
+ * The length of valid data that userspace claims to be in
+ * user_iob->data[].
+ */
+ if (get_user(len, &user_iob->length))
+ return ERR_PTR(-EFAULT);
+
+ static_assert(sizeof(user_iob->data) >= PAPR_SYSPARM_MAX_INPUT);
+ static_assert(sizeof(kern_spbuf->val) >= PAPR_SYSPARM_MAX_INPUT);
+
+ if (len > PAPR_SYSPARM_MAX_INPUT)
+ return ERR_PTR(-EINVAL);
+
+ kern_spbuf = papr_sysparm_buf_alloc();
+ if (!kern_spbuf)
+ return ERR_PTR(-ENOMEM);
+
+ papr_sysparm_buf_set_length(kern_spbuf, len);
+
+ if (len > 0 && copy_from_user(kern_spbuf->val, user_iob->data, len)) {
+ err = -EFAULT;
+ goto free_sysparm_buf;
+ }
+
+ return kern_spbuf;
+
+free_sysparm_buf:
+ papr_sysparm_buf_free(kern_spbuf);
+ return ERR_PTR(err);
+}
+
+static int papr_sysparm_buf_to_user(const struct papr_sysparm_buf *kern_spbuf,
+ struct papr_sysparm_io_block __user *user_iob)
+{
+ u16 len_out = papr_sysparm_buf_get_length(kern_spbuf);
+
+ if (put_user(len_out, &user_iob->length))
+ return -EFAULT;
+
+ static_assert(sizeof(user_iob->data) >= PAPR_SYSPARM_MAX_OUTPUT);
+ static_assert(sizeof(kern_spbuf->val) >= PAPR_SYSPARM_MAX_OUTPUT);
+
+ if (copy_to_user(user_iob->data, kern_spbuf->val, PAPR_SYSPARM_MAX_OUTPUT))
+ return -EFAULT;
+
+ return 0;
+}
+
+static long papr_sysparm_ioctl_get(struct papr_sysparm_io_block __user *user_iob)
+{
+ struct papr_sysparm_buf *kern_spbuf;
+ papr_sysparm_t param;
+ long ret;
+
+ if (get_user(param.token, &user_iob->parameter))
+ return -EFAULT;
+
+ kern_spbuf = papr_sysparm_buf_from_user(user_iob);
+ if (IS_ERR(kern_spbuf))
+ return PTR_ERR(kern_spbuf);
+
+ ret = papr_sysparm_get(param, kern_spbuf);
+ if (ret)
+ goto free_sysparm_buf;
+
+ ret = papr_sysparm_buf_to_user(kern_spbuf, user_iob);
+ if (ret)
+ goto free_sysparm_buf;
+
+ ret = 0;
+
+free_sysparm_buf:
+ papr_sysparm_buf_free(kern_spbuf);
+ return ret;
+}
+
+
+static long papr_sysparm_ioctl_set(struct papr_sysparm_io_block __user *user_iob)
+{
+ struct papr_sysparm_buf *kern_spbuf;
+ papr_sysparm_t param;
+ long ret;
+
+ if (get_user(param.token, &user_iob->parameter))
+ return -EFAULT;
+
+ kern_spbuf = papr_sysparm_buf_from_user(user_iob);
+ if (IS_ERR(kern_spbuf))
+ return PTR_ERR(kern_spbuf);
+
+ ret = papr_sysparm_set(param, kern_spbuf);
+ if (ret)
+ goto free_sysparm_buf;
+
+ ret = 0;
+
+free_sysparm_buf:
+ papr_sysparm_buf_free(kern_spbuf);
+ return ret;
+}
+
+static long papr_sysparm_ioctl(struct file *filp, unsigned int ioctl, unsigned long arg)
+{
+ void __user *argp = (__force void __user *)arg;
+ long ret;
+
+ switch (ioctl) {
+ case PAPR_SYSPARM_IOC_GET:
+ ret = papr_sysparm_ioctl_get(argp);
+ break;
+ case PAPR_SYSPARM_IOC_SET:
+ if (filp->f_mode & FMODE_WRITE)
+ ret = papr_sysparm_ioctl_set(argp);
+ else
+ ret = -EBADF;
+ break;
+ default:
+ ret = -ENOIOCTLCMD;
+ break;
+ }
+ return ret;
+}
+
+static const struct file_operations papr_sysparm_ops = {
+ .unlocked_ioctl = papr_sysparm_ioctl,
+};
+
+static struct miscdevice papr_sysparm_dev = {
+ .minor = MISC_DYNAMIC_MINOR,
+ .name = "papr-sysparm",
+ .fops = &papr_sysparm_ops,
+};
+
+static __init int papr_sysparm_init(void)
+{
+ if (!rtas_function_implemented(RTAS_FN_IBM_GET_SYSTEM_PARAMETER))
+ return -ENODEV;
+
+ return misc_register(&papr_sysparm_dev);
+}
+machine_device_initcall(pseries, papr_sysparm_init);