diff options
| -rw-r--r-- | arch/um/drivers/mconsole_kern.c | 138 | ||||
| -rw-r--r-- | arch/um/include/mem_user.h | 1 | ||||
| -rw-r--r-- | arch/um/include/os.h | 2 | ||||
| -rw-r--r-- | arch/um/os-Linux/mem.c | 27 | ||||
| -rw-r--r-- | arch/um/os-Linux/process.c | 44 | ||||
| -rw-r--r-- | arch/um/os-Linux/start_up.c | 20 |
6 files changed, 185 insertions, 47 deletions
diff --git a/arch/um/drivers/mconsole_kern.c b/arch/um/drivers/mconsole_kern.c index 1488816..d060fce 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, diff --git a/arch/um/include/mem_user.h b/arch/um/include/mem_user.h index a1064c5..a54514d 100644 --- a/arch/um/include/mem_user.h +++ b/arch/um/include/mem_user.h @@ -49,7 +49,6 @@ extern int iomem_size; extern unsigned long host_task_size; extern unsigned long task_size; -extern void check_devanon(void); extern int init_mem_user(void); extern void setup_memory(void *entry); extern unsigned long find_iomem(char *driver, unsigned long *len_out); diff --git a/arch/um/include/os.h b/arch/um/include/os.h index d3d1bc6..5fb84e8 100644 --- a/arch/um/include/os.h +++ b/arch/um/include/os.h @@ -205,6 +205,8 @@ extern int os_map_memory(void *virt, int fd, unsigned long long off, extern int os_protect_memory(void *addr, unsigned long len, int r, int w, int x); extern int os_unmap_memory(void *addr, int len); +extern int os_drop_memory(void *addr, int length); +extern int can_drop_memory(void); extern void os_flush_stdout(void); /* tt.c diff --git a/arch/um/os-Linux/mem.c b/arch/um/os-Linux/mem.c index 9d7d69a..6ab372d 100644 --- a/arch/um/os-Linux/mem.c +++ b/arch/um/os-Linux/mem.c @@ -121,36 +121,11 @@ int create_tmp_file(unsigned long long len) return(fd); } -static int create_anon_file(unsigned long long len) -{ - void *addr; - int fd; - - fd = open("/dev/anon", O_RDWR); - if(fd < 0) { - perror("opening /dev/anon"); - exit(1); - } - - addr = mmap(NULL, len, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0); - if(addr == MAP_FAILED){ - perror("mapping physmem file"); - exit(1); - } - munmap(addr, len); - - return(fd); -} - -extern int have_devanon; - int create_mem_file(unsigned long long len) { int err, fd; - if(have_devanon) - fd = create_anon_file(len); - else fd = create_tmp_file(len); + fd = create_tmp_file(len); err = os_set_exec_close(fd, 1); if(err < 0){ diff --git a/arch/um/os-Linux/process.c b/arch/um/os-Linux/process.c index d261888..8176b0b 100644 --- a/arch/um/os-Linux/process.c +++ b/arch/um/os-Linux/process.c @@ -11,6 +11,7 @@ #include <linux/unistd.h> #include <sys/mman.h> #include <sys/wait.h> +#include <sys/mman.h> #include "ptrace_user.h" #include "os.h" #include "user.h" @@ -20,6 +21,7 @@ #include "kern_util.h" #include "longjmp.h" #include "skas_ptrace.h" +#include "kern_constants.h" #define ARBITRARY_ADDR -1 #define FAILURE_PID -1 @@ -187,6 +189,48 @@ int os_unmap_memory(void *addr, int len) return(0); } +#ifndef MADV_REMOVE +#define MADV_REMOVE 0x5 /* remove these pages & resources */ +#endif + +int os_drop_memory(void *addr, int length) +{ + int err; + + err = madvise(addr, length, MADV_REMOVE); + if(err < 0) + err = -errno; + return err; +} + +int can_drop_memory(void) +{ + void *addr; + int fd; + + printk("Checking host MADV_REMOVE support..."); + fd = create_mem_file(UM_KERN_PAGE_SIZE); + if(fd < 0){ + printk("Creating test memory file failed, err = %d\n", -fd); + return 0; + } + + addr = mmap64(NULL, UM_KERN_PAGE_SIZE, PROT_READ | PROT_WRITE, + MAP_PRIVATE, fd, 0); + if(addr == MAP_FAILED){ + printk("Mapping test memory file failed, err = %d\n", -errno); + return 0; + } + + if(madvise(addr, UM_KERN_PAGE_SIZE, MADV_REMOVE) != 0){ + printk("MADV_REMOVE failed, err = %d\n", -errno); + return 0; + } + + printk("OK\n"); + return 1; +} + void init_new_thread_stack(void *sig_stack, void (*usr1_handler)(int)) { int flags = 0, pages; diff --git a/arch/um/os-Linux/start_up.c b/arch/um/os-Linux/start_up.c index 3275313..387e26a 100644 --- a/arch/um/os-Linux/start_up.c +++ b/arch/um/os-Linux/start_up.c @@ -470,25 +470,6 @@ int can_do_skas(void) } #endif -int have_devanon = 0; - -/* Runs on boot kernel stack - already safe to use printk. */ - -void check_devanon(void) -{ - int fd; - - printk("Checking for /dev/anon on the host..."); - fd = open("/dev/anon", O_RDWR); - if(fd < 0){ - printk("Not available (open failed with errno %d)\n", errno); - return; - } - - printk("OK\n"); - have_devanon = 1; -} - int __init parse_iomem(char *str, int *add) { struct iomem_region *new; @@ -664,6 +645,5 @@ void os_check_bugs(void) { check_ptrace(); check_sigio(); - check_devanon(); } |
