diff options
Diffstat (limited to 'arch/um/drivers/mconsole_kern.c')
-rw-r--r-- | arch/um/drivers/mconsole_kern.c | 140 |
1 files changed, 139 insertions, 1 deletions
diff --git a/arch/um/drivers/mconsole_kern.c b/arch/um/drivers/mconsole_kern.c index 1488816588e..28e3760e8b9 100644 --- a/arch/um/drivers/mconsole_kern.c +++ b/arch/um/drivers/mconsole_kern.c @@ -20,6 +20,8 @@ #include "linux/namei.h" #include "linux/proc_fs.h" #include "linux/syscalls.h" +#include "linux/list.h" +#include "linux/mm.h" #include "linux/console.h" #include "asm/irq.h" #include "asm/uaccess.h" @@ -347,6 +349,142 @@ static struct mc_device *mconsole_find_dev(char *name) return(NULL); } +#define UNPLUGGED_PER_PAGE \ + ((PAGE_SIZE - sizeof(struct list_head)) / sizeof(unsigned long)) + +struct unplugged_pages { + struct list_head list; + void *pages[UNPLUGGED_PER_PAGE]; +}; + +static unsigned long long unplugged_pages_count = 0; +static struct list_head unplugged_pages = LIST_HEAD_INIT(unplugged_pages); +static int unplug_index = UNPLUGGED_PER_PAGE; + +static int mem_config(char *str) +{ + unsigned long long diff; + int err = -EINVAL, i, add; + char *ret; + + if(str[0] != '=') + goto out; + + str++; + if(str[0] == '-') + add = 0; + else if(str[0] == '+'){ + add = 1; + } + else goto out; + + str++; + diff = memparse(str, &ret); + if(*ret != '\0') + goto out; + + diff /= PAGE_SIZE; + + for(i = 0; i < diff; i++){ + struct unplugged_pages *unplugged; + void *addr; + + if(add){ + if(list_empty(&unplugged_pages)) + break; + + unplugged = list_entry(unplugged_pages.next, + struct unplugged_pages, list); + if(unplug_index > 0) + addr = unplugged->pages[--unplug_index]; + else { + list_del(&unplugged->list); + addr = unplugged; + unplug_index = UNPLUGGED_PER_PAGE; + } + + free_page((unsigned long) addr); + unplugged_pages_count--; + } + else { + struct page *page; + + page = alloc_page(GFP_ATOMIC); + if(page == NULL) + break; + + unplugged = page_address(page); + if(unplug_index == UNPLUGGED_PER_PAGE){ + INIT_LIST_HEAD(&unplugged->list); + list_add(&unplugged->list, &unplugged_pages); + unplug_index = 0; + } + else { + struct list_head *entry = unplugged_pages.next; + addr = unplugged; + + unplugged = list_entry(entry, + struct unplugged_pages, + list); + unplugged->pages[unplug_index++] = addr; + err = os_drop_memory(addr, PAGE_SIZE); + if(err) + printk("Failed to release memory - " + "errno = %d\n", err); + } + + unplugged_pages_count++; + } + } + + err = 0; +out: + return err; +} + +static int mem_get_config(char *name, char *str, int size, char **error_out) +{ + char buf[sizeof("18446744073709551615")]; + int len = 0; + + sprintf(buf, "%ld", uml_physmem); + CONFIG_CHUNK(str, size, len, buf, 1); + + return len; +} + +static int mem_id(char **str, int *start_out, int *end_out) +{ + *start_out = 0; + *end_out = 0; + + return 0; +} + +static int mem_remove(int n) +{ + return -EBUSY; +} + +static struct mc_device mem_mc = { + .name = "mem", + .config = mem_config, + .get_config = mem_get_config, + .id = mem_id, + .remove = mem_remove, +}; + +static int mem_mc_init(void) +{ + if(can_drop_memory()) + mconsole_register_dev(&mem_mc); + else printk("Can't release memory to the host - memory hotplug won't " + "be supported\n"); + return 0; +} + +__initcall(mem_mc_init); + #define CONFIG_BUF_SIZE 64 static void mconsole_get_config(int (*get_config)(char *, char *, int, @@ -478,7 +616,7 @@ static void console_write(struct console *console, const char *string, return; while(1){ - n = min(len, ARRAY_SIZE(console_buf) - console_index); + n = min((size_t)len, ARRAY_SIZE(console_buf) - console_index); strncpy(&console_buf[console_index], string, n); console_index += n; string += n; |