1 files changed, 114 insertions, 0 deletions
diff --git a/arch/s390/kernel/cpcmd.c b/arch/s390/kernel/cpcmd.c
new file mode 100644
index 0000000000..b210a29d3e
--- /dev/null
+++ b/arch/s390/kernel/cpcmd.c
@@ -0,0 +1,114 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  S390 version
+ *    Copyright IBM Corp. 1999, 2007
+ *    Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
+ *               Christian Borntraeger (cborntra@de.ibm.com),
+ */
+
+#define KMSG_COMPONENT "cpcmd"
+#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/export.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/stddef.h>
+#include <linux/string.h>
+#include <linux/mm.h>
+#include <linux/io.h>
+#include <asm/diag.h>
+#include <asm/ebcdic.h>
+#include <asm/cpcmd.h>
+
+static DEFINE_SPINLOCK(cpcmd_lock);
+static char cpcmd_buf[241];
+
+static int diag8_noresponse(int cmdlen)
+{
+	asm volatile(
+		"	diag	%[rx],%[ry],0x8\n"
+		: [ry] "+&d" (cmdlen)
+		: [rx] "d" (__pa(cpcmd_buf))
+		: "cc");
+	return cmdlen;
+}
+
+static int diag8_response(int cmdlen, char *response, int *rlen)
+{
+	union register_pair rx, ry;
+	int cc;
+
+	rx.even = __pa(cpcmd_buf);
+	rx.odd	= __pa(response);
+	ry.even = cmdlen | 0x40000000L;
+	ry.odd	= *rlen;
+	asm volatile(
+		"	diag	%[rx],%[ry],0x8\n"
+		"	ipm	%[cc]\n"
+		"	srl	%[cc],28\n"
+		: [cc] "=&d" (cc), [ry] "+&d" (ry.pair)
+		: [rx] "d" (rx.pair)
+		: "cc");
+	if (cc)
+		*rlen += ry.odd;
+	else
+		*rlen = ry.odd;
+	return ry.even;
+}
+
+/*
+ * __cpcmd has some restrictions over cpcmd
+ *  - __cpcmd is unlocked and therefore not SMP-safe
+ */
+int  __cpcmd(const char *cmd, char *response, int rlen, int *response_code)
+{
+	int cmdlen;
+	int rc;
+	int response_len;
+
+	cmdlen = strlen(cmd);
+	BUG_ON(cmdlen > 240);
+	memcpy(cpcmd_buf, cmd, cmdlen);
+	ASCEBC(cpcmd_buf, cmdlen);
+
+	diag_stat_inc(DIAG_STAT_X008);
+	if (response) {
+		memset(response, 0, rlen);
+		response_len = rlen;
+		rc = diag8_response(cmdlen, response, &rlen);
+		EBCASC(response, response_len);
+        } else {
+		rc = diag8_noresponse(cmdlen);
+        }
+	if (response_code)
+		*response_code = rc;
+	return rlen;
+}
+EXPORT_SYMBOL(__cpcmd);
+
+int cpcmd(const char *cmd, char *response, int rlen, int *response_code)
+{
+	unsigned long flags;
+	char *lowbuf;
+	int len;
+
+	if (is_vmalloc_or_module_addr(response)) {
+		lowbuf = kmalloc(rlen, GFP_KERNEL);
+		if (!lowbuf) {
+			pr_warn("The cpcmd kernel function failed to allocate a response buffer\n");
+			return -ENOMEM;
+		}
+		spin_lock_irqsave(&cpcmd_lock, flags);
+		len = __cpcmd(cmd, lowbuf, rlen, response_code);
+		spin_unlock_irqrestore(&cpcmd_lock, flags);
+		memcpy(response, lowbuf, rlen);
+		kfree(lowbuf);
+	} else {
+		spin_lock_irqsave(&cpcmd_lock, flags);
+		len = __cpcmd(cmd, response, rlen, response_code);
+		spin_unlock_irqrestore(&cpcmd_lock, flags);
+	}
+	return len;
+}
+EXPORT_SYMBOL(cpcmd);