diff options
| -rw-r--r-- | arch/s390/lib/uaccess_pt.c | 105 |
1 files changed, 77 insertions, 28 deletions
diff --git a/arch/s390/lib/uaccess_pt.c b/arch/s390/lib/uaccess_pt.c index 304e07086ab..dff631d34b4 100644 --- a/arch/s390/lib/uaccess_pt.c +++ b/arch/s390/lib/uaccess_pt.c @@ -14,6 +14,63 @@ #include <asm/futex.h> #include "uaccess.h" +#ifndef CONFIG_64BIT +#define AHI "ahi" +#define SLR "slr" +#else +#define AHI "aghi" +#define SLR "slgr" +#endif + +static size_t strnlen_kernel(size_t count, const char __user *src) +{ + register unsigned long reg0 asm("0") = 0UL; + unsigned long tmp1, tmp2; + + asm volatile( + " la %2,0(%1)\n" + " la %3,0(%0,%1)\n" + " "SLR" %0,%0\n" + "0: srst %3,%2\n" + " jo 0b\n" + " la %0,1(%3)\n" /* strnlen_kernel results includes \0 */ + " "SLR" %0,%1\n" + "1:\n" + EX_TABLE(0b,1b) + : "+a" (count), "+a" (src), "=a" (tmp1), "=a" (tmp2) + : "d" (reg0) : "cc", "memory"); + return count; +} + +static size_t copy_in_kernel(size_t count, void __user *to, + const void __user *from) +{ + unsigned long tmp1; + + asm volatile( + " "AHI" %0,-1\n" + " jo 5f\n" + " bras %3,3f\n" + "0:"AHI" %0,257\n" + "1: mvc 0(1,%1),0(%2)\n" + " la %1,1(%1)\n" + " la %2,1(%2)\n" + " "AHI" %0,-1\n" + " jnz 1b\n" + " j 5f\n" + "2: mvc 0(256,%1),0(%2)\n" + " la %1,256(%1)\n" + " la %2,256(%2)\n" + "3:"AHI" %0,-256\n" + " jnm 2b\n" + "4: ex %0,1b-0b(%3)\n" + "5:"SLR" %0,%0\n" + "6:\n" + EX_TABLE(1b,6b) EX_TABLE(2b,0b) EX_TABLE(4b,0b) + : "+a" (count), "+a" (to), "+a" (from), "=a" (tmp1) + : : "cc", "memory"); + return count; +} /* * Returns kernel address for user virtual address. If the returned address is @@ -123,10 +180,8 @@ size_t copy_from_user_pt(size_t n, const void __user *from, void *to) { size_t rc; - if (segment_eq(get_fs(), KERNEL_DS)) { - memcpy(to, (void __kernel __force *) from, n); - return 0; - } + if (segment_eq(get_fs(), KERNEL_DS)) + return copy_in_kernel(n, (void __user *) to, from); rc = __user_copy_pt((unsigned long) from, to, n, 0); if (unlikely(rc)) memset(to + n - rc, 0, rc); @@ -135,30 +190,28 @@ size_t copy_from_user_pt(size_t n, const void __user *from, void *to) size_t copy_to_user_pt(size_t n, void __user *to, const void *from) { - if (segment_eq(get_fs(), KERNEL_DS)) { - memcpy((void __kernel __force *) to, from, n); - return 0; - } + if (segment_eq(get_fs(), KERNEL_DS)) + return copy_in_kernel(n, to, (void __user *) from); return __user_copy_pt((unsigned long) to, (void *) from, n, 1); } static size_t clear_user_pt(size_t n, void __user *to) { + void *zpage = &empty_zero_page; long done, size, ret; - if (segment_eq(get_fs(), KERNEL_DS)) { - memset((void __kernel __force *) to, 0, n); - return 0; - } done = 0; do { if (n - done > PAGE_SIZE) size = PAGE_SIZE; else size = n - done; - ret = __user_copy_pt((unsigned long) to + done, - &empty_zero_page, size, 1); + if (segment_eq(get_fs(), KERNEL_DS)) + ret = copy_in_kernel(n, to, (void __user *) zpage); + else + ret = __user_copy_pt((unsigned long) to, zpage, size, 1); done += size; + to += size; if (ret) return ret + n - done; } while (done < n); @@ -175,7 +228,7 @@ static size_t strnlen_user_pt(size_t count, const char __user *src) if (unlikely(!count)) return 0; if (segment_eq(get_fs(), KERNEL_DS)) - return strnlen((const char __kernel __force *) src, count) + 1; + return strnlen_kernel(count, src); done = 0; retry: spin_lock(&mm->page_table_lock); @@ -206,19 +259,17 @@ static size_t strncpy_from_user_pt(size_t count, const char __user *src, if (unlikely(!count)) return 0; - if (segment_eq(get_fs(), KERNEL_DS)) { - len = strnlen((const char __kernel __force *) src, count) + 1; - if (len > count) - len = count; - memcpy(dst, (const char __kernel __force *) src, len); - return (dst[len - 1] == '\0') ? len - 1 : len; - } done = 0; do { offset = (size_t)src & ~PAGE_MASK; len = min(count - done, PAGE_SIZE - offset); - if (__user_copy_pt((unsigned long) src, dst, len, 0)) - return -EFAULT; + if (segment_eq(get_fs(), KERNEL_DS)) { + if (copy_in_kernel(len, (void __user *) dst, src)) + return -EFAULT; + } else { + if (__user_copy_pt((unsigned long) src, dst, len, 0)) + return -EFAULT; + } len_str = strnlen(dst, len); done += len_str; src += len_str; @@ -237,10 +288,8 @@ static size_t copy_in_user_pt(size_t n, void __user *to, unsigned long kaddr_to, kaddr_from; int write_user; - if (segment_eq(get_fs(), KERNEL_DS)) { - memcpy((void __force *) to, (void __force *) from, n); - return 0; - } + if (segment_eq(get_fs(), KERNEL_DS)) + return copy_in_kernel(n, to, from); done = 0; retry: spin_lock(&mm->page_table_lock); |