1 // SPDX-License-Identifier: GPL-2.0
3  * Access kernel memory without faulting -- s390 specific implementation.
14 #include <linux/cpu.h>
17 #include <asm/asm-extable.h>
30 	unsigned long aligned, offset, count;  in s390_kernel_write_odd()  local
34 	offset = (unsigned long) dst & 7UL;  in s390_kernel_write_odd()
35 	size = min(8UL - offset, size);  in s390_kernel_write_odd()
36 	count = size - 1;  in s390_kernel_write_odd()
46 		: "a" (&tmp), "a" (&tmp[offset]), "a" (src)  in s390_kernel_write_odd()
52  * __s390_kernel_write - write to kernel memory bypassing DAT
59  * Therefore we have a read-modify-write sequence: the function reads eight
76 		size -= copied;  in __s390_kernel_write()
86 	unsigned long phys, offset;  in memcpy_real_iter()  local
93 		offset = src & ~MEMCPY_REAL_MASK;  in memcpy_real_iter()
94 		chunk = (void *)(__memcpy_real_area + offset);  in memcpy_real_iter()
95 		len = min(count, MEMCPY_REAL_SIZE - offset);  in memcpy_real_iter()
106 		count -= copied;  in memcpy_real_iter()
124 		return -EFAULT;  in memcpy_real()
129  * Find CPU that owns swapped prefix page
134 	int cpu;  in get_swapped_owner()  local
136 	for_each_online_cpu(cpu) {  in get_swapped_owner()
137 		lc = virt_to_phys(lowcore_ptr[cpu]);  in get_swapped_owner()
138 		if (addr > lc + sizeof(struct lowcore) - 1 || addr < lc)  in get_swapped_owner()
140 		return cpu;  in get_swapped_owner()
142 	return -1;  in get_swapped_owner()
157 	int this_cpu, cpu;  in xlate_dev_mem_ptr()  local
162 		cpu = get_swapped_owner(addr);  in xlate_dev_mem_ptr()
163 		if (cpu < 0)  in xlate_dev_mem_ptr()
169 	size = PAGE_SIZE - (addr & ~PAGE_MASK);  in xlate_dev_mem_ptr()
175 	} else if (cpu == this_cpu) {  in xlate_dev_mem_ptr()
176 		ptr = (void *)(addr - virt_to_phys(lowcore_ptr[cpu]));  in xlate_dev_mem_ptr()