uaccess.S
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#include <linux/linkage.h>
#include <asm-generic/export.h>
#include <asm/asm.h>
#include <asm/csr.h>
.macro fixup op reg addr lbl
100:
\op \reg, \addr
.section __ex_table,"a"
.balign RISCV_SZPTR
RISCV_PTR 100b, \lbl
.previous
.endm
ENTRY(__asm_copy_to_user)
ENTRY(__asm_copy_from_user)
/* Enable access to user memory */
li t6, SR_SUM
csrs CSR_STATUS, t6
add a3, a1, a2
/* Use word-oriented copy only if low-order bits match */
andi t0, a0, SZREG-1
andi t1, a1, SZREG-1
bne t0, t1, 2f
addi t0, a1, SZREG-1
andi t1, a3, ~(SZREG-1)
andi t0, t0, ~(SZREG-1)
/*
* a3: terminal address of source region
* t0: lowest XLEN-aligned address in source
* t1: highest XLEN-aligned address in source
*/
bgeu t0, t1, 2f
bltu a1, t0, 4f
1:
fixup REG_L, t2, (a1), 10f
fixup REG_S, t2, (a0), 10f
addi a1, a1, SZREG
addi a0, a0, SZREG
bltu a1, t1, 1b
2:
bltu a1, a3, 5f
3:
/* Disable access to user memory */
csrc CSR_STATUS, t6
li a0, 0
ret
4: /* Edge case: unalignment */
fixup lbu, t2, (a1), 10f
fixup sb, t2, (a0), 10f
addi a1, a1, 1
addi a0, a0, 1
bltu a1, t0, 4b
j 1b
5: /* Edge case: remainder */
fixup lbu, t2, (a1), 10f
fixup sb, t2, (a0), 10f
addi a1, a1, 1
addi a0, a0, 1
bltu a1, a3, 5b
j 3b
ENDPROC(__asm_copy_to_user)
ENDPROC(__asm_copy_from_user)
EXPORT_SYMBOL(__asm_copy_to_user)
EXPORT_SYMBOL(__asm_copy_from_user)
ENTRY(__clear_user)
/* Enable access to user memory */
li t6, SR_SUM
csrs CSR_STATUS, t6
add a3, a0, a1
addi t0, a0, SZREG-1
andi t1, a3, ~(SZREG-1)
andi t0, t0, ~(SZREG-1)
/*
* a3: terminal address of target region
* t0: lowest doubleword-aligned address in target region
* t1: highest doubleword-aligned address in target region
*/
bgeu t0, t1, 2f
bltu a0, t0, 4f
1:
fixup REG_S, zero, (a0), 11f
addi a0, a0, SZREG
bltu a0, t1, 1b
2:
bltu a0, a3, 5f
3:
/* Disable access to user memory */
csrc CSR_STATUS, t6
li a0, 0
ret
4: /* Edge case: unalignment */
fixup sb, zero, (a0), 11f
addi a0, a0, 1
bltu a0, t0, 4b
j 1b
5: /* Edge case: remainder */
fixup sb, zero, (a0), 11f
addi a0, a0, 1
bltu a0, a3, 5b
j 3b
ENDPROC(__clear_user)
EXPORT_SYMBOL(__clear_user)
.section .fixup,"ax"
.balign 4
/* Fixup code for __copy_user(10) and __clear_user(11) */
10:
/* Disable access to user memory */
csrs CSR_STATUS, t6
mv a0, a2
ret
11:
csrs CSR_STATUS, t6
mv a0, a1
ret
.previous