/* * User address space access functions. * * Copyright 1997 Andi Kleen * Copyright 1997 Linus Torvalds * Copyright 2002 Andi Kleen */ #include #include #include /* * Zero Userspace */ unsigned long __clear_user(void __user *addr, unsigned long size) { long __d0; might_fault(); /* no memory constraint because it doesn't change any memory gcc knows about */ stac(); asm volatile( " testq %[size8],%[size8]\n" " jz 4f\n" " .align 16\n" "0: movq $0,(%[dst])\n" " addq $8,%[dst]\n" " decl %%ecx ; jnz 0b\n" "4: movq %[size1],%%rcx\n" " testl %%ecx,%%ecx\n" " jz 2f\n" "1: movb $0,(%[dst])\n" " incq %[dst]\n" " decl %%ecx ; jnz 1b\n" "2:\n" ".section .fixup,\"ax\"\n" "3: lea 0(%[size1],%[size8],8),%[size8]\n" " jmp 2b\n" ".previous\n" _ASM_EXTABLE(0b,3b) _ASM_EXTABLE(1b,2b) : [size8] "=&c"(size), [dst] "=&D" (__d0) : [size1] "r"(size & 7), "[size8]" (size / 8), "[dst]"(addr)); clac(); return size; } EXPORT_SYMBOL(__clear_user); unsigned long clear_user(void __user *to, unsigned long n) { if (access_ok(VERIFY_WRITE, to, n)) return __clear_user(to, n); return n; } EXPORT_SYMBOL(clear_user); /* * Try to copy last bytes and clear the rest if needed. * Since protection fault in copy_from/to_user is not a normal situation, * it is not necessary to optimize tail handling. */ __visible unsigned long copy_user_handle_tail(char *to, char *from, unsigned len) { for (; len; --len, to++) { char c; if (__get_user_nocheck(c, from++, sizeof(char))) break; if (__put_user_nocheck(c, to, sizeof(char))) break; } clac(); return len; } /* * Similar to copy_user_handle_tail, probe for the write fault point, * but reuse __memcpy_mcsafe in case a new read error is encountered. * clac() is handled in _copy_to_iter_mcsafe(). */ __visible unsigned long mcsafe_handle_tail(char *to, char *from, unsigned len) { for (; len; --len, to++, from++) { /* * Call the assembly routine back directly since * memcpy_mcsafe() may silently fallback to memcpy. */ unsigned long rem = __memcpy_mcsafe(to, from, 1); if (rem) break; } return len; } #ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE /** * clean_cache_range - write back a cache range with CLWB * @vaddr: virtual start address * @size: number of bytes to write back * * Write back a cache range using the CLWB (cache line write back) * instruction. Note that @size is internally rounded up to be cache * line size aligned. */ static void clean_cache_range(void *addr, size_t size) { u16 x86_clflush_size = boot_cpu_data.x86_clflush_size; unsigned long clflush_mask = x86_clflush_size - 1; void *vend = addr + size; void *p; for (p = (void *)((unsigned long)addr & ~clflush_mask); p < vend; p += x86_clflush_size) clwb(p); } void arch_wb_cache_pmem(void *addr, size_t size) { clean_cache_range(addr, size); } EXPORT_SYMBOL_GPL(arch_wb_cache_pmem); long __copy_user_flushcache(void *dst, const void __user *src, unsigned size) { unsigned long flushed, dest = (unsigned long) dst; long rc = __copy_user_nocache(dst, src, size, 0); /* * __copy_user_nocache() uses non-temporal stores for the bulk * of the transfer, but we need to manually flush if the * transfer is unaligned. A cached memory copy is used when * destination or size is not naturally aligned. That is: * - Require 8-byte alignment when size is 8 bytes or larger. * - Require 4-byte alignment when size is 4 bytes. */ if (size < 8) { if (!IS_ALIGNED(dest, 4) || size != 4) clean_cache_range(dst, size); } else { if (!IS_ALIGNED(dest, 8)) { dest = ALIGN(dest, boot_cpu_data.x86_clflush_size); clean_cache_range(dst, 1); } flushed = dest - (unsigned long) dst; if (size > flushed && !IS_ALIGNED(size - flushed, 8)) clean_cache_range(dst + size - 1, 1); } return rc; } void memcpy_flushcache(void *_dst, const void *_src, size_t size) { unsigned long dest = (unsigned long) _dst; unsigned long source = (unsigned long) _src; /* cache copy and flush to align dest */ if (!IS_ALIGNED(dest, 8)) { size_t len = min_t(size_t, size, ALIGN(dest, 8) - dest); memcpy((void *) dest, (void *) source, len); clean_cache_range((void *) dest, len); dest += len; source += len; size -= len; if (!size) return; } /* 4x8 movnti loop */ while (size >= 32) { asm("movq (%0), %%r8\n" "movq 8(%0), %%r9\n" "movq 16(%0), %%r10\n" "movq 24(%0), %%r11\n" "movnti %%r8, (%1)\n" "movnti %%r9, 8(%1)\n" "movnti %%r10, 16(%1)\n" "movnti %%r11, 24(%1)\n" :: "r" (source), "r" (dest) : "memory", "r8", "r9", "r10", "r11"); dest += 32; source += 32; size -= 32; } /* 1x8 movnti loop */ while (size >= 8) { asm("movq (%0), %%r8\n" "movnti %%r8, (%1)\n" :: "r" (source), "r" (dest) : "memory", "r8"); dest += 8; source += 8; size -= 8; } /* 1x4 movnti loop */ while (size >= 4) { asm("movl (%0), %%r8d\n" "movnti %%r8d, (%1)\n" :: "r" (source), "r" (dest) : "memory", "r8"); dest += 4; source += 4; size -= 4; } /* cache copy for remaining bytes */ if (size) { memcpy((void *) dest, (void *) source, size); clean_cache_range((void *) dest, size); } } EXPORT_SYMBOL_GPL(memcpy_flushcache); void memcpy_page_flushcache(char *to, struct page *page, size_t offset, size_t len) { char *from = kmap_atomic(page); memcpy_flushcache(to, from + offset, len); kunmap_atomic(from); } #endif