diff options
Diffstat (limited to 'arch/um/os-Linux/process.c')
| -rw-r--r-- | arch/um/os-Linux/process.c | 44 |
1 files changed, 44 insertions, 0 deletions
diff --git a/arch/um/os-Linux/process.c b/arch/um/os-Linux/process.c index d261888f39c43..8176b0b520470 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; |