[PATCH 3/3] s390/diag: Add diag204 IOCTL to diag misc device

[Mete Durlu <meted@linux.ibm.com>]

Add IOCTL implementation necessary to fetch diag204 data from the new
diag misc device under /dev.

Signed-off-by: Mete Durlu <meted@linux.ibm.com>
---
 arch/s390/include/uapi/asm/diag.h  |  8 +++++++
 arch/s390/kernel/diag/diag204.c    | 43 ++++++++++++++++++++++++++++++++++++++
 arch/s390/kernel/diag/diag_ioctl.h |  3 +++
 arch/s390/kernel/diag/diag_misc.c  | 10 +++++++++
 4 files changed, 64 insertions(+)

diff --git a/arch/s390/include/uapi/asm/diag.h b/arch/s390/include/uapi/asm/diag.h
index b7e6ccb4ff6e..985667b2917a 100644
--- a/arch/s390/include/uapi/asm/diag.h
+++ b/arch/s390/include/uapi/asm/diag.h
@@ -22,11 +22,19 @@ struct diag310_memtop {
 	__u64 nesting_lvl;
 };
 
+struct diag204_request {
+	__u64 address;
+	int allow_busy;
+	int allow_busy_wait;
+};
+
 /* Diag ioctl definitions */
 #define DIAG324_GET_PIBBUF	_IOWR(DIAG_MAGIC_STR, 0x77, struct diag324_pib)
 #define DIAG324_GET_PIBLEN	_IOR(DIAG_MAGIC_STR, 0x78, size_t)
 #define DIAG310_GET_STRIDE	_IOR(DIAG_MAGIC_STR, 0x79, size_t)
 #define DIAG310_GET_MEMTOPLEN	_IOWR(DIAG_MAGIC_STR, 0x7a, size_t)
 #define DIAG310_GET_MEMTOPBUF	_IOWR(DIAG_MAGIC_STR, 0x7b, struct diag310_memtop)
+#define DIAG204_GET_LEN		_IOR(DIAG_MAGIC_STR, 0x7c, size_t)
+#define DIAG204_GET_BUF		_IOWR(DIAG_MAGIC_STR, 0x7d, struct diag204_request)
 
 #endif /* __S390_UAPI_ASM_DIAG_H */
diff --git a/arch/s390/kernel/diag/diag204.c b/arch/s390/kernel/diag/diag204.c
index 8e1909e6caf9..967b6e0bc667 100644
--- a/arch/s390/kernel/diag/diag204.c
+++ b/arch/s390/kernel/diag/diag204.c
@@ -14,6 +14,8 @@
 #include <linux/vmalloc.h>
 
 #include <asm/diag.h>
+#include <uapi/asm/diag.h>
+#include "diag_ioctl.h"
 
 struct diag204_info {
 	int pages;			/* number of pages for diag204 data */
@@ -268,6 +270,47 @@ int diag204_store(void *buf, int allow_busy, int allow_busy_wait)
 	return rc;
 }
 
+long diag204_len(unsigned long arg)
+{
+	if (!diag204_is_available())
+		return -EOPNOTSUPP;
+	if (put_user(diag204_get_buf_size(), (size_t __user *)arg))
+		return -EFAULT;
+	return 0;
+}
+
+long diag204_buf(unsigned long arg)
+{
+	struct diag204_request __user *udata;
+	int rc, allow_busy, allow_busy_wait;
+	u64 address;
+	void *buf;
+
+	if (!diag204_is_available())
+		return -EOPNOTSUPP;
+	udata = (struct diag204_request __user *)arg;
+	if (get_user(address, &udata->address))
+		return -EFAULT;
+	if (get_user(allow_busy, &udata->allow_busy))
+		return -EFAULT;
+	if (get_user(allow_busy_wait, &udata->allow_busy_wait))
+		return -EFAULT;
+	buf = diag204_allocate_buffer();
+	if (!buf)
+		return -ENOMEM;
+	rc = diag204_store(buf, allow_busy, allow_busy_wait);
+	if (rc < 0) {
+		diag204_free_buffer(buf);
+		return rc;
+	}
+	rc = copy_to_user((void __user *)address, buf,
+			  diag204_get_buf_size());
+	if (rc < 0)
+		rc = -EFAULT;
+	diag204_free_buffer(buf);
+	return rc;
+}
+
 /*
  * diag204_probe() has to find out, which type of diagnose 204 implementation
  * we have on our machine. Currently there are three possible scanarios:
diff --git a/arch/s390/kernel/diag/diag_ioctl.h b/arch/s390/kernel/diag/diag_ioctl.h
index 7080be946785..7718b57ffe3e 100644
--- a/arch/s390/kernel/diag/diag_ioctl.h
+++ b/arch/s390/kernel/diag/diag_ioctl.h
@@ -4,6 +4,9 @@
 
 #include <linux/types.h>
 
+long diag204_len(unsigned long arg);
+long diag204_buf(unsigned long arg);
+
 long diag324_pibbuf(unsigned long arg);
 long diag324_piblen(unsigned long arg);
 
diff --git a/arch/s390/kernel/diag/diag_misc.c b/arch/s390/kernel/diag/diag_misc.c
index efffe02ea02e..ac263baf8d08 100644
--- a/arch/s390/kernel/diag/diag_misc.c
+++ b/arch/s390/kernel/diag/diag_misc.c
@@ -35,6 +35,16 @@ static long diag_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 	case DIAG310_GET_MEMTOPBUF:
 		rc = diag310_memtop_buf(arg);
 		break;
+	case DIAG204_GET_LEN:
+		rc = -EPERM;
+		if (capable(CAP_SYS_ADMIN))
+			rc = diag204_len(arg);
+		break;
+	case DIAG204_GET_BUF:
+		rc = -EPERM;
+		if (capable(CAP_SYS_ADMIN))
+			rc = diag204_buf(arg);
+		break;
 	default:
 		rc = -ENOIOCTLCMD;
 		break;

-- 
2.56.0