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Diffstat (limited to 'arch/mips/mm/cex-sb1.S')
| -rw-r--r-- | arch/mips/mm/cex-sb1.S | 170 |
1 files changed, 170 insertions, 0 deletions
diff --git a/arch/mips/mm/cex-sb1.S b/arch/mips/mm/cex-sb1.S new file mode 100644 index 000000000000..2c3a23aa88c3 --- /dev/null +++ b/arch/mips/mm/cex-sb1.S @@ -0,0 +1,170 @@ +/* + * 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. + */ + + __INIT + + .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) + + /* + * 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 occurence 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 + +END(except_vec2_sb1) + + __FINIT + + 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) |