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-rw-r--r--arch/s390/mm/cmm.c441
1 files changed, 441 insertions, 0 deletions
diff --git a/arch/s390/mm/cmm.c b/arch/s390/mm/cmm.c
new file mode 100644
index 000000000..9141ed4c5
--- /dev/null
+++ b/arch/s390/mm/cmm.c
@@ -0,0 +1,441 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Collaborative memory management interface.
+ *
+ * Copyright IBM Corp 2003, 2010
+ * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>,
+ *
+ */
+
+#include <linux/errno.h>
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/gfp.h>
+#include <linux/sched.h>
+#include <linux/string_helpers.h>
+#include <linux/sysctl.h>
+#include <linux/swap.h>
+#include <linux/kthread.h>
+#include <linux/oom.h>
+#include <linux/uaccess.h>
+
+#include <asm/diag.h>
+
+#ifdef CONFIG_CMM_IUCV
+static char *cmm_default_sender = "VMRMSVM";
+#endif
+static char *sender;
+module_param(sender, charp, 0400);
+MODULE_PARM_DESC(sender,
+ "Guest name that may send SMSG messages (default VMRMSVM)");
+
+#include "../../../drivers/s390/net/smsgiucv.h"
+
+#define CMM_NR_PAGES ((PAGE_SIZE / sizeof(unsigned long)) - 2)
+
+struct cmm_page_array {
+ struct cmm_page_array *next;
+ unsigned long index;
+ unsigned long pages[CMM_NR_PAGES];
+};
+
+static long cmm_pages;
+static long cmm_timed_pages;
+static volatile long cmm_pages_target;
+static volatile long cmm_timed_pages_target;
+static long cmm_timeout_pages;
+static long cmm_timeout_seconds;
+
+static struct cmm_page_array *cmm_page_list;
+static struct cmm_page_array *cmm_timed_page_list;
+static DEFINE_SPINLOCK(cmm_lock);
+
+static struct task_struct *cmm_thread_ptr;
+static DECLARE_WAIT_QUEUE_HEAD(cmm_thread_wait);
+
+static void cmm_timer_fn(struct timer_list *);
+static void cmm_set_timer(void);
+static DEFINE_TIMER(cmm_timer, cmm_timer_fn);
+
+static long cmm_alloc_pages(long nr, long *counter,
+ struct cmm_page_array **list)
+{
+ struct cmm_page_array *pa, *npa;
+ unsigned long addr;
+
+ while (nr) {
+ addr = __get_free_page(GFP_NOIO);
+ if (!addr)
+ break;
+ spin_lock(&cmm_lock);
+ pa = *list;
+ if (!pa || pa->index >= CMM_NR_PAGES) {
+ /* Need a new page for the page list. */
+ spin_unlock(&cmm_lock);
+ npa = (struct cmm_page_array *)
+ __get_free_page(GFP_NOIO);
+ if (!npa) {
+ free_page(addr);
+ break;
+ }
+ spin_lock(&cmm_lock);
+ pa = *list;
+ if (!pa || pa->index >= CMM_NR_PAGES) {
+ npa->next = pa;
+ npa->index = 0;
+ pa = npa;
+ *list = pa;
+ } else
+ free_page((unsigned long) npa);
+ }
+ diag10_range(virt_to_pfn(addr), 1);
+ pa->pages[pa->index++] = addr;
+ (*counter)++;
+ spin_unlock(&cmm_lock);
+ nr--;
+ }
+ return nr;
+}
+
+static long cmm_free_pages(long nr, long *counter, struct cmm_page_array **list)
+{
+ struct cmm_page_array *pa;
+ unsigned long addr;
+
+ spin_lock(&cmm_lock);
+ pa = *list;
+ while (nr) {
+ if (!pa || pa->index <= 0)
+ break;
+ addr = pa->pages[--pa->index];
+ if (pa->index == 0) {
+ pa = pa->next;
+ free_page((unsigned long) *list);
+ *list = pa;
+ }
+ free_page(addr);
+ (*counter)--;
+ nr--;
+ }
+ spin_unlock(&cmm_lock);
+ return nr;
+}
+
+static int cmm_oom_notify(struct notifier_block *self,
+ unsigned long dummy, void *parm)
+{
+ unsigned long *freed = parm;
+ long nr = 256;
+
+ nr = cmm_free_pages(nr, &cmm_timed_pages, &cmm_timed_page_list);
+ if (nr > 0)
+ nr = cmm_free_pages(nr, &cmm_pages, &cmm_page_list);
+ cmm_pages_target = cmm_pages;
+ cmm_timed_pages_target = cmm_timed_pages;
+ *freed += 256 - nr;
+ return NOTIFY_OK;
+}
+
+static struct notifier_block cmm_oom_nb = {
+ .notifier_call = cmm_oom_notify,
+};
+
+static int cmm_thread(void *dummy)
+{
+ int rc;
+
+ while (1) {
+ rc = wait_event_interruptible(cmm_thread_wait,
+ cmm_pages != cmm_pages_target ||
+ cmm_timed_pages != cmm_timed_pages_target ||
+ kthread_should_stop());
+ if (kthread_should_stop() || rc == -ERESTARTSYS) {
+ cmm_pages_target = cmm_pages;
+ cmm_timed_pages_target = cmm_timed_pages;
+ break;
+ }
+ if (cmm_pages_target > cmm_pages) {
+ if (cmm_alloc_pages(1, &cmm_pages, &cmm_page_list))
+ cmm_pages_target = cmm_pages;
+ } else if (cmm_pages_target < cmm_pages) {
+ cmm_free_pages(1, &cmm_pages, &cmm_page_list);
+ }
+ if (cmm_timed_pages_target > cmm_timed_pages) {
+ if (cmm_alloc_pages(1, &cmm_timed_pages,
+ &cmm_timed_page_list))
+ cmm_timed_pages_target = cmm_timed_pages;
+ } else if (cmm_timed_pages_target < cmm_timed_pages) {
+ cmm_free_pages(1, &cmm_timed_pages,
+ &cmm_timed_page_list);
+ }
+ if (cmm_timed_pages > 0 && !timer_pending(&cmm_timer))
+ cmm_set_timer();
+ }
+ return 0;
+}
+
+static void cmm_kick_thread(void)
+{
+ wake_up(&cmm_thread_wait);
+}
+
+static void cmm_set_timer(void)
+{
+ if (cmm_timed_pages_target <= 0 || cmm_timeout_seconds <= 0) {
+ if (timer_pending(&cmm_timer))
+ del_timer(&cmm_timer);
+ return;
+ }
+ mod_timer(&cmm_timer, jiffies + msecs_to_jiffies(cmm_timeout_seconds * MSEC_PER_SEC));
+}
+
+static void cmm_timer_fn(struct timer_list *unused)
+{
+ long nr;
+
+ nr = cmm_timed_pages_target - cmm_timeout_pages;
+ if (nr < 0)
+ cmm_timed_pages_target = 0;
+ else
+ cmm_timed_pages_target = nr;
+ cmm_kick_thread();
+ cmm_set_timer();
+}
+
+static void cmm_set_pages(long nr)
+{
+ cmm_pages_target = nr;
+ cmm_kick_thread();
+}
+
+static long cmm_get_pages(void)
+{
+ return cmm_pages;
+}
+
+static void cmm_add_timed_pages(long nr)
+{
+ cmm_timed_pages_target += nr;
+ cmm_kick_thread();
+}
+
+static long cmm_get_timed_pages(void)
+{
+ return cmm_timed_pages;
+}
+
+static void cmm_set_timeout(long nr, long seconds)
+{
+ cmm_timeout_pages = nr;
+ cmm_timeout_seconds = seconds;
+ cmm_set_timer();
+}
+
+static int cmm_skip_blanks(char *cp, char **endp)
+{
+ char *str;
+
+ for (str = cp; *str == ' ' || *str == '\t'; str++)
+ ;
+ *endp = str;
+ return str != cp;
+}
+
+static int cmm_pages_handler(struct ctl_table *ctl, int write,
+ void *buffer, size_t *lenp, loff_t *ppos)
+{
+ long nr = cmm_get_pages();
+ struct ctl_table ctl_entry = {
+ .procname = ctl->procname,
+ .data = &nr,
+ .maxlen = sizeof(long),
+ };
+ int rc;
+
+ rc = proc_doulongvec_minmax(&ctl_entry, write, buffer, lenp, ppos);
+ if (rc < 0 || !write)
+ return rc;
+
+ cmm_set_pages(nr);
+ return 0;
+}
+
+static int cmm_timed_pages_handler(struct ctl_table *ctl, int write,
+ void *buffer, size_t *lenp,
+ loff_t *ppos)
+{
+ long nr = cmm_get_timed_pages();
+ struct ctl_table ctl_entry = {
+ .procname = ctl->procname,
+ .data = &nr,
+ .maxlen = sizeof(long),
+ };
+ int rc;
+
+ rc = proc_doulongvec_minmax(&ctl_entry, write, buffer, lenp, ppos);
+ if (rc < 0 || !write)
+ return rc;
+
+ cmm_add_timed_pages(nr);
+ return 0;
+}
+
+static int cmm_timeout_handler(struct ctl_table *ctl, int write,
+ void *buffer, size_t *lenp, loff_t *ppos)
+{
+ char buf[64], *p;
+ long nr, seconds;
+ unsigned int len;
+
+ if (!*lenp || (*ppos && !write)) {
+ *lenp = 0;
+ return 0;
+ }
+
+ if (write) {
+ len = min(*lenp, sizeof(buf));
+ memcpy(buf, buffer, len);
+ buf[len - 1] = '\0';
+ cmm_skip_blanks(buf, &p);
+ nr = simple_strtoul(p, &p, 0);
+ cmm_skip_blanks(p, &p);
+ seconds = simple_strtoul(p, &p, 0);
+ cmm_set_timeout(nr, seconds);
+ *ppos += *lenp;
+ } else {
+ len = sprintf(buf, "%ld %ld\n",
+ cmm_timeout_pages, cmm_timeout_seconds);
+ if (len > *lenp)
+ len = *lenp;
+ memcpy(buffer, buf, len);
+ *lenp = len;
+ *ppos += len;
+ }
+ return 0;
+}
+
+static struct ctl_table cmm_table[] = {
+ {
+ .procname = "cmm_pages",
+ .mode = 0644,
+ .proc_handler = cmm_pages_handler,
+ },
+ {
+ .procname = "cmm_timed_pages",
+ .mode = 0644,
+ .proc_handler = cmm_timed_pages_handler,
+ },
+ {
+ .procname = "cmm_timeout",
+ .mode = 0644,
+ .proc_handler = cmm_timeout_handler,
+ },
+ { }
+};
+
+static struct ctl_table cmm_dir_table[] = {
+ {
+ .procname = "vm",
+ .maxlen = 0,
+ .mode = 0555,
+ .child = cmm_table,
+ },
+ { }
+};
+
+#ifdef CONFIG_CMM_IUCV
+#define SMSG_PREFIX "CMM"
+static void cmm_smsg_target(const char *from, char *msg)
+{
+ long nr, seconds;
+
+ if (strlen(sender) > 0 && strcmp(from, sender) != 0)
+ return;
+ if (!cmm_skip_blanks(msg + strlen(SMSG_PREFIX), &msg))
+ return;
+ if (strncmp(msg, "SHRINK", 6) == 0) {
+ if (!cmm_skip_blanks(msg + 6, &msg))
+ return;
+ nr = simple_strtoul(msg, &msg, 0);
+ cmm_skip_blanks(msg, &msg);
+ if (*msg == '\0')
+ cmm_set_pages(nr);
+ } else if (strncmp(msg, "RELEASE", 7) == 0) {
+ if (!cmm_skip_blanks(msg + 7, &msg))
+ return;
+ nr = simple_strtoul(msg, &msg, 0);
+ cmm_skip_blanks(msg, &msg);
+ if (*msg == '\0')
+ cmm_add_timed_pages(nr);
+ } else if (strncmp(msg, "REUSE", 5) == 0) {
+ if (!cmm_skip_blanks(msg + 5, &msg))
+ return;
+ nr = simple_strtoul(msg, &msg, 0);
+ if (!cmm_skip_blanks(msg, &msg))
+ return;
+ seconds = simple_strtoul(msg, &msg, 0);
+ cmm_skip_blanks(msg, &msg);
+ if (*msg == '\0')
+ cmm_set_timeout(nr, seconds);
+ }
+}
+#endif
+
+static struct ctl_table_header *cmm_sysctl_header;
+
+static int __init cmm_init(void)
+{
+ int rc = -ENOMEM;
+
+ cmm_sysctl_header = register_sysctl_table(cmm_dir_table);
+ if (!cmm_sysctl_header)
+ goto out_sysctl;
+#ifdef CONFIG_CMM_IUCV
+ /* convert sender to uppercase characters */
+ if (sender)
+ string_upper(sender, sender);
+ else
+ sender = cmm_default_sender;
+
+ rc = smsg_register_callback(SMSG_PREFIX, cmm_smsg_target);
+ if (rc < 0)
+ goto out_smsg;
+#endif
+ rc = register_oom_notifier(&cmm_oom_nb);
+ if (rc < 0)
+ goto out_oom_notify;
+ cmm_thread_ptr = kthread_run(cmm_thread, NULL, "cmmthread");
+ if (!IS_ERR(cmm_thread_ptr))
+ return 0;
+
+ rc = PTR_ERR(cmm_thread_ptr);
+ unregister_oom_notifier(&cmm_oom_nb);
+out_oom_notify:
+#ifdef CONFIG_CMM_IUCV
+ smsg_unregister_callback(SMSG_PREFIX, cmm_smsg_target);
+out_smsg:
+#endif
+ unregister_sysctl_table(cmm_sysctl_header);
+out_sysctl:
+ del_timer_sync(&cmm_timer);
+ return rc;
+}
+module_init(cmm_init);
+
+static void __exit cmm_exit(void)
+{
+ unregister_sysctl_table(cmm_sysctl_header);
+#ifdef CONFIG_CMM_IUCV
+ smsg_unregister_callback(SMSG_PREFIX, cmm_smsg_target);
+#endif
+ unregister_oom_notifier(&cmm_oom_nb);
+ kthread_stop(cmm_thread_ptr);
+ del_timer_sync(&cmm_timer);
+ cmm_free_pages(cmm_pages, &cmm_pages, &cmm_page_list);
+ cmm_free_pages(cmm_timed_pages, &cmm_timed_pages, &cmm_timed_page_list);
+}
+module_exit(cmm_exit);
+
+MODULE_LICENSE("GPL");