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-rw-r--r--arch/s390/kernel/cpcmd.c114
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);