1#include <linux/linkage.h>
  2#include <asm/asm.h>
  3#include <asm/csr.h>
  4
  5	.altmacro
  6	.macro fixup op reg addr lbl
  7	LOCAL _epc
  8_epc:
  9	\op \reg, \addr
 10	.section __ex_table,"a"
 11	.balign RISCV_SZPTR
 12	RISCV_PTR _epc, \lbl
 13	.previous
 14	.endm
 15
 16ENTRY(__asm_copy_to_user)
 17ENTRY(__asm_copy_from_user)
 18
 19	/* Enable access to user memory */
 20	li t6, SR_SUM
 21	csrs CSR_SSTATUS, t6
 22
 23	add a3, a1, a2
 24	/* Use word-oriented copy only if low-order bits match */
 25	andi t0, a0, SZREG-1
 26	andi t1, a1, SZREG-1
 27	bne t0, t1, 2f
 28
 29	addi t0, a1, SZREG-1
 30	andi t1, a3, ~(SZREG-1)
 31	andi t0, t0, ~(SZREG-1)
 32	/*
 33	 * a3: terminal address of source region
 34	 * t0: lowest XLEN-aligned address in source
 35	 * t1: highest XLEN-aligned address in source
 36	 */
 37	bgeu t0, t1, 2f
 38	bltu a1, t0, 4f
 391:
 40	fixup REG_L, t2, (a1), 10f
 41	fixup REG_S, t2, (a0), 10f
 42	addi a1, a1, SZREG
 43	addi a0, a0, SZREG
 44	bltu a1, t1, 1b
 452:
 46	bltu a1, a3, 5f
 47
 483:
 49	/* Disable access to user memory */
 50	csrc CSR_SSTATUS, t6
 51	li a0, 0
 52	ret
 534: /* Edge case: unalignment */
 54	fixup lbu, t2, (a1), 10f
 55	fixup sb, t2, (a0), 10f
 56	addi a1, a1, 1
 57	addi a0, a0, 1
 58	bltu a1, t0, 4b
 59	j 1b
 605: /* Edge case: remainder */
 61	fixup lbu, t2, (a1), 10f
 62	fixup sb, t2, (a0), 10f
 63	addi a1, a1, 1
 64	addi a0, a0, 1
 65	bltu a1, a3, 5b
 66	j 3b
 67ENDPROC(__asm_copy_to_user)
 68ENDPROC(__asm_copy_from_user)
 69
 70
 71ENTRY(__clear_user)
 72
 73	/* Enable access to user memory */
 74	li t6, SR_SUM
 75	csrs CSR_SSTATUS, t6
 76
 77	add a3, a0, a1
 78	addi t0, a0, SZREG-1
 79	andi t1, a3, ~(SZREG-1)
 80	andi t0, t0, ~(SZREG-1)
 81	/*
 82	 * a3: terminal address of target region
 83	 * t0: lowest doubleword-aligned address in target region
 84	 * t1: highest doubleword-aligned address in target region
 85	 */
 86	bgeu t0, t1, 2f
 87	bltu a0, t0, 4f
 881:
 89	fixup REG_S, zero, (a0), 11f
 90	addi a0, a0, SZREG
 91	bltu a0, t1, 1b
 922:
 93	bltu a0, a3, 5f
 94
 953:
 96	/* Disable access to user memory */
 97	csrc CSR_SSTATUS, t6
 98	li a0, 0
 99	ret
1004: /* Edge case: unalignment */
101	fixup sb, zero, (a0), 11f
102	addi a0, a0, 1
103	bltu a0, t0, 4b
104	j 1b
1055: /* Edge case: remainder */
106	fixup sb, zero, (a0), 11f
107	addi a0, a0, 1
108	bltu a0, a3, 5b
109	j 3b
110ENDPROC(__clear_user)
111
112	.section .fixup,"ax"
113	.balign 4
114	/* Fixup code for __copy_user(10) and __clear_user(11) */
11510:
116	/* Disable access to user memory */
117	csrs CSR_SSTATUS, t6
118	mv a0, a2
119	ret
12011:
121	csrs CSR_SSTATUS, t6
122	mv a0, a1
123	ret
124	.previous