coreboot-kgpe-d16/src/arch/riscv/virtual_memory.c
Xiang Wang c1dc7932b5 riscv: don't write to mstatus.XS
XS is a read-only field of mstatus. Unable to be write. So remove this code.

Change-Id: I3ad6b0029900124ac7cce062e668a0ea5a8b2c0e
Signed-off-by: Xiang Wang <wxjstz@126.com>
Reviewed-on: https://review.coreboot.org/28357
Reviewed-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
Reviewed-by: Philipp Hug <philipp@hug.cx>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
2018-09-16 08:36:10 +00:00

69 lines
2.2 KiB
C

/*
* Early initialization code for riscv virtual memory
*
* Copyright 2015 Google Inc.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; version 2 of
* the License.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.See the
* GNU General Public License for more details.
*/
#include <arch/cpu.h>
#include <arch/encoding.h>
#include <stdint.h>
#include <vm.h>
/* Delegate controls which traps are delegated to the payload. If you
* wish to temporarily disable some or all delegation you can, in a
* debugger, set it to a different value (e.g. 0 to have all traps go
* to M-mode). In practice, this variable has been a lifesaver. It is
* still not quite determined which delegation might by unallowed by
* the spec so for now we enumerate and set them all. */
static int delegate = 0
| (1 << CAUSE_MISALIGNED_FETCH)
| (1 << CAUSE_FETCH_ACCESS)
| (1 << CAUSE_ILLEGAL_INSTRUCTION)
| (1 << CAUSE_BREAKPOINT)
| (1 << CAUSE_LOAD_ACCESS)
| (1 << CAUSE_STORE_ACCESS)
| (1 << CAUSE_USER_ECALL)
| (1 << CAUSE_FETCH_PAGE_FAULT)
| (1 << CAUSE_LOAD_PAGE_FAULT)
| (1 << CAUSE_STORE_PAGE_FAULT)
;
void mstatus_init(void)
{
uintptr_t ms = 0;
ms = INSERT_FIELD(ms, MSTATUS_FS, 3);
write_csr(mstatus, ms);
// clear any pending timer interrupts.
clear_csr(mip, MIP_STIP | MIP_SSIP);
// enable machine and supervisor timer and
// all other supervisor interrupts.
set_csr(mie, MIP_MTIP | MIP_STIP | MIP_SSIP);
// Delegate supervisor timer and other interrupts to supervisor mode,
// if supervisor mode is supported.
if (supports_extension('S')) {
set_csr(mideleg, MIP_STIP | MIP_SSIP);
set_csr(medeleg, delegate);
}
// Enable all user/supervisor-mode counters using
// v1.10 register addresses.
// They moved from the earlier spec.
// Until we trust our toolchain use the hardcoded constants.
// These were in flux and people who get the older toolchain
// will have difficult-to-debug failures.
write_csr(/*mcounteren*/0x306, 7);
}