diff options
Diffstat (limited to 'arch/s390/mm/maccess.c')
| -rw-r--r-- | arch/s390/mm/maccess.c | 72 |
1 files changed, 72 insertions, 0 deletions
diff --git a/arch/s390/mm/maccess.c b/arch/s390/mm/maccess.c index 51e5cd9b906..1cb8427bedf 100644 --- a/arch/s390/mm/maccess.c +++ b/arch/s390/mm/maccess.c @@ -11,6 +11,7 @@ #include <linux/kernel.h> #include <linux/types.h> #include <linux/errno.h> +#include <linux/gfp.h> #include <asm/system.h> /* @@ -60,6 +61,9 @@ long probe_kernel_write(void *dst, const void *src, size_t size) return copied < 0 ? -EFAULT : 0; } +/* + * Copy memory in real mode (kernel to kernel) + */ int memcpy_real(void *dest, void *src, size_t count) { register unsigned long _dest asm("2") = (unsigned long) dest; @@ -85,3 +89,71 @@ int memcpy_real(void *dest, void *src, size_t count) arch_local_irq_restore(flags); return rc; } + +/* + * Copy memory to absolute zero + */ +void copy_to_absolute_zero(void *dest, void *src, size_t count) +{ + unsigned long cr0; + + BUG_ON((unsigned long) dest + count >= sizeof(struct _lowcore)); + preempt_disable(); + __ctl_store(cr0, 0, 0); + __ctl_clear_bit(0, 28); /* disable lowcore protection */ + memcpy_real(dest + store_prefix(), src, count); + __ctl_load(cr0, 0, 0); + preempt_enable(); +} + +/* + * Copy memory from kernel (real) to user (virtual) + */ +int copy_to_user_real(void __user *dest, void *src, size_t count) +{ + int offs = 0, size, rc; + char *buf; + + buf = (char *) __get_free_page(GFP_KERNEL); + if (!buf) + return -ENOMEM; + rc = -EFAULT; + while (offs < count) { + size = min(PAGE_SIZE, count - offs); + if (memcpy_real(buf, src + offs, size)) + goto out; + if (copy_to_user(dest + offs, buf, size)) + goto out; + offs += size; + } + rc = 0; +out: + free_page((unsigned long) buf); + return rc; +} + +/* + * Copy memory from user (virtual) to kernel (real) + */ +int copy_from_user_real(void *dest, void __user *src, size_t count) +{ + int offs = 0, size, rc; + char *buf; + + buf = (char *) __get_free_page(GFP_KERNEL); + if (!buf) + return -ENOMEM; + rc = -EFAULT; + while (offs < count) { + size = min(PAGE_SIZE, count - offs); + if (copy_from_user(buf, src + offs, size)) + goto out; + if (memcpy_real(dest + offs, buf, size)) + goto out; + offs += size; + } + rc = 0; +out: + free_page((unsigned long) buf); + return rc; +} |