linux/arch/riscv/lib/uaccess.S
Christoph Hellwig a4c3733d32 riscv: abstract out CSR names for supervisor vs machine mode
Many of the privileged CSRs exist in a supervisor and machine version
that are used very similarly.  Provide versions of the CSR names and
fields that map to either the S-mode or M-mode variant depending on
a new CONFIG_RISCV_M_MODE kconfig symbol.

Contains contributions from Damien Le Moal <Damien.LeMoal@wdc.com>
and Paul Walmsley <paul.walmsley@sifive.com>.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Thomas Gleixner <tglx@linutronix.de> # for drivers/clocksource, drivers/irqchip
[paul.walmsley@sifive.com: updated to apply]
Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
2019-11-05 09:20:42 -08:00

125 lines
2.2 KiB
ArmAsm

#include <linux/linkage.h>
#include <asm/asm.h>
#include <asm/csr.h>
.altmacro
.macro fixup op reg addr lbl
LOCAL _epc
_epc:
\op \reg, \addr
.section __ex_table,"a"
.balign RISCV_SZPTR
RISCV_PTR _epc, \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)
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)
.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