u-boot/arch/riscv/lib/interrupts.c
Anup Patel d2db2a8fa4 riscv: Add kconfig option to run U-Boot in S-mode
This patch adds kconfig option RISCV_SMODE to run U-Boot in
S-mode. When this opition is enabled we use s<xyz> CSRs instead
of m<xyz> CSRs.

It is important to note that there is no equivalent S-mode CSR
for misa and mhartid CSRs so we expect M-mode runtime firmware
(BBL or equivalent) to emulate misa and mhartid CSR read.

In-future, we will have more patches to avoid accessing misa and
mhartid CSRs from S-mode.

Signed-off-by: Anup Patel <anup@brainfault.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Tested-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Lukas Auer <lukas.auer@aisec.fraunhofer.de>
2018-12-05 14:13:53 +08:00

105 lines
2 KiB
C

// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright (c) 2016-17 Microsemi Corporation.
* Padmarao Begari, Microsemi Corporation <padmarao.begari@microsemi.com>
*
* Copyright (C) 2017 Andes Technology Corporation
* Rick Chen, Andes Technology Corporation <rick@andestech.com>
*/
#include <common.h>
#include <asm/ptrace.h>
#include <asm/system.h>
#include <asm/encoding.h>
static void _exit_trap(ulong code, ulong epc, struct pt_regs *regs);
int interrupt_init(void)
{
return 0;
}
/*
* enable interrupts
*/
void enable_interrupts(void)
{
}
/*
* disable interrupts
*/
int disable_interrupts(void)
{
return 0;
}
ulong handle_trap(ulong cause, ulong epc, struct pt_regs *regs)
{
ulong is_irq, irq;
is_irq = (cause & MCAUSE_INT);
irq = (cause & ~MCAUSE_INT);
if (is_irq) {
switch (irq) {
case IRQ_M_EXT:
case IRQ_S_EXT:
external_interrupt(0); /* handle external interrupt */
break;
case IRQ_M_TIMER:
case IRQ_S_TIMER:
timer_interrupt(0); /* handle timer interrupt */
break;
default:
_exit_trap(cause, epc, regs);
break;
};
} else {
_exit_trap(cause, epc, regs);
}
return epc;
}
/*
*Entry Point for PLIC Interrupt Handler
*/
__attribute__((weak)) void external_interrupt(struct pt_regs *regs)
{
}
__attribute__((weak)) void timer_interrupt(struct pt_regs *regs)
{
}
static void _exit_trap(ulong code, ulong epc, struct pt_regs *regs)
{
static const char * const exception_code[] = {
"Instruction address misaligned",
"Instruction access fault",
"Illegal instruction",
"Breakpoint",
"Load address misaligned",
"Load access fault",
"Store/AMO address misaligned",
"Store/AMO access fault",
"Environment call from U-mode",
"Environment call from S-mode",
"Reserved",
"Environment call from M-mode",
"Instruction page fault",
"Load page fault",
"Reserved",
"Store/AMO page fault",
};
if (code < ARRAY_SIZE(exception_code)) {
printf("exception code: %ld , %s , epc %lx , ra %lx\n",
code, exception_code[code], epc, regs->ra);
} else {
printf("Reserved\n");
}
hang();
}