| // SPDX-License-Identifier: GPL-2.0 |
| /* |
| * Standard user space access functions based on mvcp/mvcs and doing |
| * interesting things in the secondary space mode. |
| * |
| * Copyright IBM Corp. 2006,2014 |
| * Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com), |
| * Gerald Schaefer (gerald.schaefer@de.ibm.com) |
| */ |
| |
| #include <linux/jump_label.h> |
| #include <linux/uaccess.h> |
| #include <linux/export.h> |
| #include <linux/errno.h> |
| #include <linux/mm.h> |
| #include <asm/mmu_context.h> |
| #include <asm/facility.h> |
| |
| #ifndef CONFIG_HAVE_MARCH_Z10_FEATURES |
| static DEFINE_STATIC_KEY_FALSE(have_mvcos); |
| |
| static int __init uaccess_init(void) |
| { |
| if (test_facility(27)) |
| static_branch_enable(&have_mvcos); |
| return 0; |
| } |
| early_initcall(uaccess_init); |
| |
| static inline int copy_with_mvcos(void) |
| { |
| if (static_branch_likely(&have_mvcos)) |
| return 1; |
| return 0; |
| } |
| #else |
| static inline int copy_with_mvcos(void) |
| { |
| return 1; |
| } |
| #endif |
| |
| void set_fs(mm_segment_t fs) |
| { |
| current->thread.mm_segment = fs; |
| if (fs == USER_DS) { |
| __ctl_load(S390_lowcore.user_asce, 1, 1); |
| clear_cpu_flag(CIF_ASCE_PRIMARY); |
| } else { |
| __ctl_load(S390_lowcore.kernel_asce, 1, 1); |
| set_cpu_flag(CIF_ASCE_PRIMARY); |
| } |
| if (fs & 1) { |
| if (fs == USER_DS_SACF) |
| __ctl_load(S390_lowcore.user_asce, 7, 7); |
| else |
| __ctl_load(S390_lowcore.kernel_asce, 7, 7); |
| set_cpu_flag(CIF_ASCE_SECONDARY); |
| } |
| } |
| EXPORT_SYMBOL(set_fs); |
| |
| mm_segment_t enable_sacf_uaccess(void) |
| { |
| mm_segment_t old_fs; |
| unsigned long asce, cr; |
| |
| old_fs = current->thread.mm_segment; |
| if (old_fs & 1) |
| return old_fs; |
| current->thread.mm_segment |= 1; |
| asce = S390_lowcore.kernel_asce; |
| if (likely(old_fs == USER_DS)) { |
| __ctl_store(cr, 1, 1); |
| if (cr != S390_lowcore.kernel_asce) { |
| __ctl_load(S390_lowcore.kernel_asce, 1, 1); |
| set_cpu_flag(CIF_ASCE_PRIMARY); |
| } |
| asce = S390_lowcore.user_asce; |
| } |
| __ctl_store(cr, 7, 7); |
| if (cr != asce) { |
| __ctl_load(asce, 7, 7); |
| set_cpu_flag(CIF_ASCE_SECONDARY); |
| } |
| return old_fs; |
| } |
| EXPORT_SYMBOL(enable_sacf_uaccess); |
| |
| void disable_sacf_uaccess(mm_segment_t old_fs) |
| { |
| current->thread.mm_segment = old_fs; |
| if (old_fs == USER_DS && test_facility(27)) { |
| __ctl_load(S390_lowcore.user_asce, 1, 1); |
| clear_cpu_flag(CIF_ASCE_PRIMARY); |
| } |
| } |
| EXPORT_SYMBOL(disable_sacf_uaccess); |
| |
| static inline unsigned long copy_from_user_mvcos(void *x, const void __user *ptr, |
| unsigned long size) |
| { |
| register unsigned long reg0 asm("0") = 0x01UL; |
| unsigned long tmp1, tmp2; |
| |
| tmp1 = -4096UL; |
| asm volatile( |
| "0: .insn ss,0xc80000000000,0(%0,%2),0(%1),0\n" |
| "6: jz 4f\n" |
| "1: algr %0,%3\n" |
| " slgr %1,%3\n" |
| " slgr %2,%3\n" |
| " j 0b\n" |
| "2: la %4,4095(%1)\n"/* %4 = ptr + 4095 */ |
| " nr %4,%3\n" /* %4 = (ptr + 4095) & -4096 */ |
| " slgr %4,%1\n" |
| " clgr %0,%4\n" /* copy crosses next page boundary? */ |
| " jnh 5f\n" |
| "3: .insn ss,0xc80000000000,0(%4,%2),0(%1),0\n" |
| "7: slgr %0,%4\n" |
| " j 5f\n" |
| "4: slgr %0,%0\n" |
| "5:\n" |
| EX_TABLE(0b,2b) EX_TABLE(3b,5b) EX_TABLE(6b,2b) EX_TABLE(7b,5b) |
| : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2) |
| : "d" (reg0) : "cc", "memory"); |
| return size; |
| } |
| |
| static inline unsigned long copy_from_user_mvcp(void *x, const void __user *ptr, |
| unsigned long size) |
| { |
| unsigned long tmp1, tmp2; |
| mm_segment_t old_fs; |
| |
| old_fs = enable_sacf_uaccess(); |
| tmp1 = -256UL; |
| asm volatile( |
| " sacf 0\n" |
| "0: mvcp 0(%0,%2),0(%1),%3\n" |
| "7: jz 5f\n" |
| "1: algr %0,%3\n" |
| " la %1,256(%1)\n" |
| " la %2,256(%2)\n" |
| "2: mvcp 0(%0,%2),0(%1),%3\n" |
| "8: jnz 1b\n" |
| " j 5f\n" |
| "3: la %4,255(%1)\n" /* %4 = ptr + 255 */ |
| " lghi %3,-4096\n" |
| " nr %4,%3\n" /* %4 = (ptr + 255) & -4096 */ |
| " slgr %4,%1\n" |
| " clgr %0,%4\n" /* copy crosses next page boundary? */ |
| " jnh 6f\n" |
| "4: mvcp 0(%4,%2),0(%1),%3\n" |
| "9: slgr %0,%4\n" |
| " j 6f\n" |
| "5: slgr %0,%0\n" |
| "6: sacf 768\n" |
| EX_TABLE(0b,3b) EX_TABLE(2b,3b) EX_TABLE(4b,6b) |
| EX_TABLE(7b,3b) EX_TABLE(8b,3b) EX_TABLE(9b,6b) |
| : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2) |
| : : "cc", "memory"); |
| disable_sacf_uaccess(old_fs); |
| return size; |
| } |
| |
| unsigned long raw_copy_from_user(void *to, const void __user *from, unsigned long n) |
| { |
| if (copy_with_mvcos()) |
| return copy_from_user_mvcos(to, from, n); |
| return copy_from_user_mvcp(to, from, n); |
| } |
| EXPORT_SYMBOL(raw_copy_from_user); |
| |
| static inline unsigned long copy_to_user_mvcos(void __user *ptr, const void *x, |
| unsigned long size) |
| { |
| register unsigned long reg0 asm("0") = 0x010000UL; |
| unsigned long tmp1, tmp2; |
| |
| tmp1 = -4096UL; |
| asm volatile( |
| "0: .insn ss,0xc80000000000,0(%0,%1),0(%2),0\n" |
| "6: jz 4f\n" |
| "1: algr %0,%3\n" |
| " slgr %1,%3\n" |
| " slgr %2,%3\n" |
| " j 0b\n" |
| "2: la %4,4095(%1)\n"/* %4 = ptr + 4095 */ |
| " nr %4,%3\n" /* %4 = (ptr + 4095) & -4096 */ |
| " slgr %4,%1\n" |
| " clgr %0,%4\n" /* copy crosses next page boundary? */ |
| " jnh 5f\n" |
| "3: .insn ss,0xc80000000000,0(%4,%1),0(%2),0\n" |
| "7: slgr %0,%4\n" |
| " j 5f\n" |
| "4: slgr %0,%0\n" |
| "5:\n" |
| EX_TABLE(0b,2b) EX_TABLE(3b,5b) EX_TABLE(6b,2b) EX_TABLE(7b,5b) |
| : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2) |
| : "d" (reg0) : "cc", "memory"); |
| return size; |
| } |
| |
| static inline unsigned long copy_to_user_mvcs(void __user *ptr, const void *x, |
| unsigned long size) |
| { |
| unsigned long tmp1, tmp2; |
| mm_segment_t old_fs; |
| |
| old_fs = enable_sacf_uaccess(); |
| tmp1 = -256UL; |
| asm volatile( |
| " sacf 0\n" |
| "0: mvcs 0(%0,%1),0(%2),%3\n" |
| "7: jz 5f\n" |
| "1: algr %0,%3\n" |
| " la %1,256(%1)\n" |
| " la %2,256(%2)\n" |
| "2: mvcs 0(%0,%1),0(%2),%3\n" |
| "8: jnz 1b\n" |
| " j 5f\n" |
| "3: la %4,255(%1)\n" /* %4 = ptr + 255 */ |
| " lghi %3,-4096\n" |
| " nr %4,%3\n" /* %4 = (ptr + 255) & -4096 */ |
| " slgr %4,%1\n" |
| " clgr %0,%4\n" /* copy crosses next page boundary? */ |
| " jnh 6f\n" |
| "4: mvcs 0(%4,%1),0(%2),%3\n" |
| "9: slgr %0,%4\n" |
| " j 6f\n" |
| "5: slgr %0,%0\n" |
| "6: sacf 768\n" |
| EX_TABLE(0b,3b) EX_TABLE(2b,3b) EX_TABLE(4b,6b) |
| EX_TABLE(7b,3b) EX_TABLE(8b,3b) EX_TABLE(9b,6b) |
| : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2) |
| : : "cc", "memory"); |
| disable_sacf_uaccess(old_fs); |
| return size; |
| } |
| |
| unsigned long raw_copy_to_user(void __user *to, const void *from, unsigned long n) |
| { |
| if (copy_with_mvcos()) |
| return copy_to_user_mvcos(to, from, n); |
| return copy_to_user_mvcs(to, from, n); |
| } |
| EXPORT_SYMBOL(raw_copy_to_user); |
| |
| static inline unsigned long copy_in_user_mvcos(void __user *to, const void __user *from, |
| unsigned long size) |
| { |
| register unsigned long reg0 asm("0") = 0x010001UL; |
| unsigned long tmp1, tmp2; |
| |
| tmp1 = -4096UL; |
| /* FIXME: copy with reduced length. */ |
| asm volatile( |
| "0: .insn ss,0xc80000000000,0(%0,%1),0(%2),0\n" |
| " jz 2f\n" |
| "1: algr %0,%3\n" |
| " slgr %1,%3\n" |
| " slgr %2,%3\n" |
| " j 0b\n" |
| "2:slgr %0,%0\n" |
| "3: \n" |
| EX_TABLE(0b,3b) |
| : "+a" (size), "+a" (to), "+a" (from), "+a" (tmp1), "=a" (tmp2) |
| : "d" (reg0) : "cc", "memory"); |
| return size; |
| } |
| |
| static inline unsigned long copy_in_user_mvc(void __user *to, const void __user *from, |
| unsigned long size) |
| { |
| mm_segment_t old_fs; |
| unsigned long tmp1; |
| |
| old_fs = enable_sacf_uaccess(); |
| asm volatile( |
| " sacf 256\n" |
| " aghi %0,-1\n" |
| " jo 5f\n" |
| " bras %3,3f\n" |
| "0: aghi %0,257\n" |
| "1: mvc 0(1,%1),0(%2)\n" |
| " la %1,1(%1)\n" |
| " la %2,1(%2)\n" |
| " aghi %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: aghi %0,-256\n" |
| " jnm 2b\n" |
| "4: ex %0,1b-0b(%3)\n" |
| "5: slgr %0,%0\n" |
| "6: sacf 768\n" |
| EX_TABLE(1b,6b) EX_TABLE(2b,0b) EX_TABLE(4b,0b) |
| : "+a" (size), "+a" (to), "+a" (from), "=a" (tmp1) |
| : : "cc", "memory"); |
| disable_sacf_uaccess(old_fs); |
| return size; |
| } |
| |
| unsigned long raw_copy_in_user(void __user *to, const void __user *from, unsigned long n) |
| { |
| if (copy_with_mvcos()) |
| return copy_in_user_mvcos(to, from, n); |
| return copy_in_user_mvc(to, from, n); |
| } |
| EXPORT_SYMBOL(raw_copy_in_user); |
| |
| static inline unsigned long clear_user_mvcos(void __user *to, unsigned long size) |
| { |
| register unsigned long reg0 asm("0") = 0x010000UL; |
| unsigned long tmp1, tmp2; |
| |
| tmp1 = -4096UL; |
| asm volatile( |
| "0: .insn ss,0xc80000000000,0(%0,%1),0(%4),0\n" |
| " jz 4f\n" |
| "1: algr %0,%2\n" |
| " slgr %1,%2\n" |
| " j 0b\n" |
| "2: la %3,4095(%1)\n"/* %4 = to + 4095 */ |
| " nr %3,%2\n" /* %4 = (to + 4095) & -4096 */ |
| " slgr %3,%1\n" |
| " clgr %0,%3\n" /* copy crosses next page boundary? */ |
| " jnh 5f\n" |
| "3: .insn ss,0xc80000000000,0(%3,%1),0(%4),0\n" |
| " slgr %0,%3\n" |
| " j 5f\n" |
| "4: slgr %0,%0\n" |
| "5:\n" |
| EX_TABLE(0b,2b) EX_TABLE(3b,5b) |
| : "+a" (size), "+a" (to), "+a" (tmp1), "=a" (tmp2) |
| : "a" (empty_zero_page), "d" (reg0) : "cc", "memory"); |
| return size; |
| } |
| |
| static inline unsigned long clear_user_xc(void __user *to, unsigned long size) |
| { |
| mm_segment_t old_fs; |
| unsigned long tmp1, tmp2; |
| |
| old_fs = enable_sacf_uaccess(); |
| asm volatile( |
| " sacf 256\n" |
| " aghi %0,-1\n" |
| " jo 5f\n" |
| " bras %3,3f\n" |
| " xc 0(1,%1),0(%1)\n" |
| "0: aghi %0,257\n" |
| " la %2,255(%1)\n" /* %2 = ptr + 255 */ |
| " srl %2,12\n" |
| " sll %2,12\n" /* %2 = (ptr + 255) & -4096 */ |
| " slgr %2,%1\n" |
| " clgr %0,%2\n" /* clear crosses next page boundary? */ |
| " jnh 5f\n" |
| " aghi %2,-1\n" |
| "1: ex %2,0(%3)\n" |
| " aghi %2,1\n" |
| " slgr %0,%2\n" |
| " j 5f\n" |
| "2: xc 0(256,%1),0(%1)\n" |
| " la %1,256(%1)\n" |
| "3: aghi %0,-256\n" |
| " jnm 2b\n" |
| "4: ex %0,0(%3)\n" |
| "5: slgr %0,%0\n" |
| "6: sacf 768\n" |
| EX_TABLE(1b,6b) EX_TABLE(2b,0b) EX_TABLE(4b,0b) |
| : "+a" (size), "+a" (to), "=a" (tmp1), "=a" (tmp2) |
| : : "cc", "memory"); |
| disable_sacf_uaccess(old_fs); |
| return size; |
| } |
| |
| unsigned long __clear_user(void __user *to, unsigned long size) |
| { |
| if (copy_with_mvcos()) |
| return clear_user_mvcos(to, size); |
| return clear_user_xc(to, size); |
| } |
| EXPORT_SYMBOL(__clear_user); |
| |
| static inline unsigned long strnlen_user_srst(const char __user *src, |
| unsigned long size) |
| { |
| register unsigned long reg0 asm("0") = 0; |
| unsigned long tmp1, tmp2; |
| |
| asm volatile( |
| " la %2,0(%1)\n" |
| " la %3,0(%0,%1)\n" |
| " slgr %0,%0\n" |
| " sacf 256\n" |
| "0: srst %3,%2\n" |
| " jo 0b\n" |
| " la %0,1(%3)\n" /* strnlen_user results includes \0 */ |
| " slgr %0,%1\n" |
| "1: sacf 768\n" |
| EX_TABLE(0b,1b) |
| : "+a" (size), "+a" (src), "=a" (tmp1), "=a" (tmp2) |
| : "d" (reg0) : "cc", "memory"); |
| return size; |
| } |
| |
| unsigned long __strnlen_user(const char __user *src, unsigned long size) |
| { |
| mm_segment_t old_fs; |
| unsigned long len; |
| |
| if (unlikely(!size)) |
| return 0; |
| old_fs = enable_sacf_uaccess(); |
| len = strnlen_user_srst(src, size); |
| disable_sacf_uaccess(old_fs); |
| return len; |
| } |
| EXPORT_SYMBOL(__strnlen_user); |
| |
| long __strncpy_from_user(char *dst, const char __user *src, long size) |
| { |
| size_t done, len, offset, len_str; |
| |
| if (unlikely(size <= 0)) |
| return 0; |
| done = 0; |
| do { |
| offset = (size_t)src & (L1_CACHE_BYTES - 1); |
| len = min(size - done, L1_CACHE_BYTES - offset); |
| if (copy_from_user(dst, src, len)) |
| return -EFAULT; |
| len_str = strnlen(dst, len); |
| done += len_str; |
| src += len_str; |
| dst += len_str; |
| } while ((len_str == len) && (done < size)); |
| return done; |
| } |
| EXPORT_SYMBOL(__strncpy_from_user); |
