linux_dsm_epyc7002/arch/riscv/lib/uaccess.S
Palmer Dabbelt abc71bf0a7
RISC-V: Stop using LOCAL for the uaccess fixups
LLVM's integrated assembler doesn't support the LOCAL directive, which we're
using when generating our uaccess fixup tables.  Luckily the table fragment is
small enough that there's only one internal symbol, so using a relative symbol
reference doesn't really complicate anything.

Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-03-03 10:45:14 -08:00

127 lines
2.3 KiB
ArmAsm

#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