/*
* Copyright (C) 2001,2002,2003 Broadcom Corporation
*
* 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; either version 2
* of the License, or (at your option) any later version.
*
* 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.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#include <linux/init.h>
#include <asm/asm.h>
#include <asm/regdef.h>
#include <asm/mipsregs.h>
#include <asm/stackframe.h>
#include <asm/cacheops.h>
#include <asm/sibyte/board.h>
#define C0_ERRCTL $26 /* CP0: Error info */
#define C0_CERR_I $27 /* CP0: Icache error */
#define C0_CERR_D $27,1 /* CP0: Dcache error */
/*
* Based on SiByte sample software cache-err/cerr.S
* CVS revision 1.8. Only the 'unrecoverable' case
* is changed.
*/
.set mips64
.set noreorder
.set noat
/*
* sb1_cerr_vec: code to be copied to the Cache Error
* Exception vector. The code must be pushed out to memory
* (either by copying to Kseg0 and Kseg1 both, or by flushing
* the L1 and L2) since it is fetched as 0xa0000100.
*
* NOTE: Be sure this handler is at most 28 instructions long
* since the final 16 bytes of the exception vector memory
* (0x170-0x17f) are used to preserve k0, k1, and ra.
*/
LEAF(except_vec2_sb1)
/*
* If this error is recoverable, we need to exit the handler
* without having dirtied any registers. To do this,
* save/restore k0 and k1 from low memory (Useg is direct
* mapped while ERL=1). Note that we can't save to a
* CPU-specific location without ruining a register in the
* process. This means we are vulnerable to data corruption
* whenever the handler is reentered by a second CPU.
*/
sd k0,0x170($0)
sd k1,0x178($0)
#ifdef CONFIG_SB1_CEX_ALWAYS_FATAL
j handle_vec2_sb1
nop
#else
/*
* M_ERRCTL_RECOVERABLE is bit 31, which makes it easy to tell
* if we can fast-path out of here for a h/w-recovered error.
*/
mfc0 k1,C0_ERRCTL
bgtz k1,attempt_recovery
sll k0,k1,1
recovered_dcache:
/*
* Unlock CacheErr-D (which in turn unlocks CacheErr-DPA).
* Ought to log the occurrence of this recovered dcache error.
*/
b recovered
mtc0 $0,C0_CERR_D
attempt_recovery:
/*
* k0 has C0_ERRCTL << 1, which puts 'DC' at bit 31. Any
* Dcache errors we can recover from will take more extensive
* processing. For now, they are considered "unrecoverable".
* Note that 'DC' becoming set (outside of ERL mode) will
* cause 'IC' to clear; so if there's an Icache error, we'll
* only find out about it if we recover from this error and
* continue executing.
*/
bltz k0,unrecoverable
sll k0,1
/*
* k0 has C0_ERRCTL << 2, which puts 'IC' at bit 31. If an
* Icache error isn't indicated, I'm not sure why we got here.
* Consider that case "unrecoverable" for now.
*/
bgez k0,unrecoverable
attempt_icache_recovery:
/*
* External icache errors are due to uncorrectable ECC errors
* in the L2 cache or Memory Controller and cannot be
* recovered here.
*/
mfc0 k0,C0_CERR_I /* delay slot */
li k1,1 << 26 /* ICACHE_EXTERNAL */
and k1,k0
bnez k1,unrecoverable
andi k0,0x1fe0
/*
* Since the error is internal, the 'IDX' field from
* CacheErr-I is valid and we can just invalidate all blocks
* in that set.
*/
cache Index_Invalidate_I,(0<<13)(k0)
cache Index_Invalidate_I,(1<<13)(k0)
cache Index_Invalidate_I,(2<<13)(k0)
cache Index_Invalidate_I,(3<<13)(k0)
/* Ought to log this recovered icache error */
recovered:
/* Restore the saved registers */
ld k0,0x170($0)
ld k1,0x178($0)
eret
unrecoverable:
/* Unrecoverable Icache or Dcache error; log it and/or fail */
j handle_vec2_sb1
nop
#endif
END(except_vec2_sb1)
LEAF(handle_vec2_sb1)
mfc0 k0,CP0_CONFIG
li k1,~CONF_CM_CMASK
and k0,k0,k1
ori k0,k0,CONF_CM_UNCACHED
mtc0 k0,CP0_CONFIG
SSNOP
SSNOP
SSNOP
SSNOP
bnezl $0, 1f
1:
mfc0 k0, CP0_STATUS
sll k0, k0, 3 # check CU0 (kernel?)
bltz k0, 2f
nop
/* Get a valid Kseg0 stack pointer. Any task's stack pointer
* will do, although if we ever want to resume execution we
* better not have corrupted any state. */
get_saved_sp
move sp, k1
2:
j sb1_cache_error
nop
END(handle_vec2_sb1)
