diff options
| -rw-r--r-- | arch/um/include/shared/os.h | 1 | ||||
| -rw-r--r-- | arch/um/kernel/Makefile | 2 | ||||
| -rw-r--r-- | arch/um/kernel/maccess.c | 24 | ||||
| -rw-r--r-- | arch/um/os-Linux/process.c | 52 |
4 files changed, 78 insertions, 1 deletions
diff --git a/arch/um/include/shared/os.h b/arch/um/include/shared/os.h index 95feaa47a2f..c70a234a3f8 100644 --- a/arch/um/include/shared/os.h +++ b/arch/um/include/shared/os.h @@ -200,6 +200,7 @@ 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); +extern int os_mincore(void *addr, unsigned long len); /* execvp.c */ extern int execvp_noalloc(char *buf, const char *file, char *const argv[]); diff --git a/arch/um/kernel/Makefile b/arch/um/kernel/Makefile index babe21826e3..d8b78a03855 100644 --- a/arch/um/kernel/Makefile +++ b/arch/um/kernel/Makefile @@ -13,7 +13,7 @@ clean-files := obj-y = config.o exec.o exitcode.o irq.o ksyms.o mem.o \ physmem.o process.o ptrace.o reboot.o sigio.o \ signal.o smp.o syscall.o sysrq.o time.o tlb.o trap.o \ - um_arch.o umid.o skas/ + um_arch.o umid.o maccess.o skas/ obj-$(CONFIG_BLK_DEV_INITRD) += initrd.o obj-$(CONFIG_GPROF) += gprof_syms.o diff --git a/arch/um/kernel/maccess.c b/arch/um/kernel/maccess.c new file mode 100644 index 00000000000..1f3d5c4910d --- /dev/null +++ b/arch/um/kernel/maccess.c @@ -0,0 +1,24 @@ +/* + * Copyright (C) 2013 Richard Weinberger <richrd@nod.at> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include <linux/uaccess.h> +#include <linux/kernel.h> +#include <os.h> + +long probe_kernel_read(void *dst, const void *src, size_t size) +{ + void *psrc = (void *)rounddown((unsigned long)src, PAGE_SIZE); + + if ((unsigned long)src < PAGE_SIZE || size <= 0) + return -EFAULT; + + if (os_mincore(psrc, size + src - psrc) <= 0) + return -EFAULT; + + return __probe_kernel_read(dst, src, size); +} diff --git a/arch/um/os-Linux/process.c b/arch/um/os-Linux/process.c index b8f34c9e53a..67b9c8f5a89 100644 --- a/arch/um/os-Linux/process.c +++ b/arch/um/os-Linux/process.c @@ -4,6 +4,7 @@ */ #include <stdio.h> +#include <stdlib.h> #include <unistd.h> #include <errno.h> #include <signal.h> @@ -232,6 +233,57 @@ out: return ok; } +static int os_page_mincore(void *addr) +{ + char vec[2]; + int ret; + + ret = mincore(addr, UM_KERN_PAGE_SIZE, vec); + if (ret < 0) { + if (errno == ENOMEM || errno == EINVAL) + return 0; + else + return -errno; + } + + return vec[0] & 1; +} + +int os_mincore(void *addr, unsigned long len) +{ + char *vec; + int ret, i; + + if (len <= UM_KERN_PAGE_SIZE) + return os_page_mincore(addr); + + vec = calloc(1, (len + UM_KERN_PAGE_SIZE - 1) / UM_KERN_PAGE_SIZE); + if (!vec) + return -ENOMEM; + + ret = mincore(addr, UM_KERN_PAGE_SIZE, vec); + if (ret < 0) { + if (errno == ENOMEM || errno == EINVAL) + ret = 0; + else + ret = -errno; + + goto out; + } + + for (i = 0; i < ((len + UM_KERN_PAGE_SIZE - 1) / UM_KERN_PAGE_SIZE); i++) { + if (!(vec[i] & 1)) { + ret = 0; + goto out; + } + } + + ret = 1; +out: + free(vec); + return ret; +} + void init_new_thread_signals(void) { set_handler(SIGSEGV); |