From a4b5bd9abcf5b0586de68722ff8e9b91020279bf Mon Sep 17 00:00:00 2001 From: Andrew Isaacson Date: Wed, 19 Oct 2005 23:57:40 -0700 Subject: [PATCH] SB1 cache exception handling. Expand SB1 cache error handling by adding SB1_CEX_ALWAYS_FATAL and SB1_CEX_STALL, allowing configurable behavior on cache errors. Signed-Off-By: Andy Isaacson Signed-off-by: Ralf Baechle --- arch/mips/mm/cerr-sb1.c | 54 ++++++++++++++++++++++++++++++++++------ arch/mips/mm/cex-sb1.S | 5 ++++ arch/mips/sibyte/Kconfig | 8 ++++++ 3 files changed, 59 insertions(+), 8 deletions(-) diff --git a/arch/mips/mm/cerr-sb1.c b/arch/mips/mm/cerr-sb1.c index 7166ffe63502..1cf3c6006ccd 100644 --- a/arch/mips/mm/cerr-sb1.c +++ b/arch/mips/mm/cerr-sb1.c @@ -19,13 +19,19 @@ #include #include #include +#include -#ifndef CONFIG_SIBYTE_BUS_WATCHER +#if !defined(CONFIG_SIBYTE_BUS_WATCHER) || defined(CONFIG_SIBYTE_BW_TRACE) #include -#include #include #endif +/* + * We'd like to dump the L2_ECC_TAG register on errors, but errata make + * that unsafe... So for now we don't. (BCM1250/BCM112x erratum SOC-48.) + */ +#undef DUMP_L2_ECC_TAG_ON_ERROR + /* SB1 definitions */ /* XXX should come from config1 XXX */ @@ -139,12 +145,18 @@ static inline void breakout_cerrd(unsigned int val) static void check_bus_watcher(void) { uint32_t status, l2_err, memio_err; +#ifdef DUMP_L2_ECC_TAG_ON_ERROR + uint64_t l2_tag; +#endif /* Destructive read, clears register and interrupt */ status = csr_in32(IOADDR(A_SCD_BUS_ERR_STATUS)); /* Bit 31 is always on, but there's no #define for that */ if (status & ~(1UL << 31)) { l2_err = csr_in32(IOADDR(A_BUS_L2_ERRORS)); +#ifdef DUMP_L2_ECC_TAG_ON_ERROR + l2_tag = in64(IO_SPACE_BASE | A_L2_ECC_TAG); +#endif memio_err = csr_in32(IOADDR(A_BUS_MEM_IO_ERRORS)); prom_printf("Bus watcher error counters: %08x %08x\n", l2_err, memio_err); prom_printf("\nLast recorded signature:\n"); @@ -153,6 +165,9 @@ static void check_bus_watcher(void) (int)(G_SCD_BERR_TID(status) >> 6), (int)G_SCD_BERR_RID(status), (int)G_SCD_BERR_DCODE(status)); +#ifdef DUMP_L2_ECC_TAG_ON_ERROR + prom_printf("Last L2 tag w/ bad ECC: %016llx\n", l2_tag); +#endif } else { prom_printf("Bus watcher indicates no error\n"); } @@ -166,6 +181,16 @@ asmlinkage void sb1_cache_error(void) uint64_t cerr_dpa; uint32_t errctl, cerr_i, cerr_d, dpalo, dpahi, eepc, res; +#ifdef CONFIG_SIBYTE_BW_TRACE + /* Freeze the trace buffer now */ +#if defined(CONFIG_SIBYTE_BCM1x55) || defined(CONFIG_SIBYTE_BCM1x80) + csr_out32(M_BCM1480_SCD_TRACE_CFG_FREEZE, IO_SPACE_BASE | A_SCD_TRACE_CFG); +#else + csr_out32(M_SCD_TRACE_CFG_FREEZE, IO_SPACE_BASE | A_SCD_TRACE_CFG); +#endif + prom_printf("Trace buffer frozen\n"); +#endif + prom_printf("Cache error exception on CPU %x:\n", (read_c0_prid() >> 25) & 0x7); @@ -229,11 +254,19 @@ asmlinkage void sb1_cache_error(void) check_bus_watcher(); - while (1); /* - * This tends to make things get really ugly; let's just stall instead. - * panic("Can't handle the cache error!"); + * Calling panic() when a fatal cache error occurs scrambles the + * state of the system (and the cache), making it difficult to + * investigate after the fact. However, if you just stall the CPU, + * the other CPU may keep on running, which is typically very + * undesirable. */ +#ifdef CONFIG_SB1_CERR_STALL + while (1) + ; +#else + panic("unhandled cache error"); +#endif } @@ -434,7 +467,8 @@ static struct dc_state dc_states[] = { }; #define DC_TAG_VALID(state) \ - (((state) == 0xf) || ((state) == 0x13) || ((state) == 0x19) || ((state == 0x16)) || ((state) == 0x1c)) + (((state) == 0x0) || ((state) == 0xf) || ((state) == 0x13) || \ + ((state) == 0x19) || ((state) == 0x16) || ((state) == 0x1c)) static char *dc_state_str(unsigned char state) { @@ -505,6 +539,7 @@ static uint32_t extract_dc(unsigned short addr, int data) uint64_t datalo; uint32_t datalohi, datalolo, datahi; int offset; + char bad_ecc = 0; for (offset = 0; offset < 4; offset++) { /* Index-load-data-D */ @@ -525,8 +560,7 @@ static uint32_t extract_dc(unsigned short addr, int data) ecc = dc_ecc(datalo); if (ecc != datahi) { int bits = 0; - prom_printf(" ** bad ECC (%02x %02x) ->", - datahi, ecc); + bad_ecc |= 1 << (3-offset); ecc ^= datahi; while (ecc) { if (ecc & 1) bits++; @@ -537,6 +571,10 @@ static uint32_t extract_dc(unsigned short addr, int data) prom_printf(" %02X-%016llX", datahi, datalo); } prom_printf("\n"); + if (bad_ecc) + prom_printf(" dwords w/ bad ECC: %d %d %d %d\n", + !!(bad_ecc & 8), !!(bad_ecc & 4), + !!(bad_ecc & 2), !!(bad_ecc & 1)); } } return res; diff --git a/arch/mips/mm/cex-sb1.S b/arch/mips/mm/cex-sb1.S index 2c3a23aa88c3..0e71580774ff 100644 --- a/arch/mips/mm/cex-sb1.S +++ b/arch/mips/mm/cex-sb1.S @@ -64,6 +64,10 @@ LEAF(except_vec2_sb1) sd k0,0x170($0) sd k1,0x178($0) +#if 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. @@ -134,6 +138,7 @@ unrecoverable: /* Unrecoverable Icache or Dcache error; log it and/or fail */ j handle_vec2_sb1 nop +#endif END(except_vec2_sb1) diff --git a/arch/mips/sibyte/Kconfig b/arch/mips/sibyte/Kconfig index 6a5a08f5e212..de46f62ac462 100644 --- a/arch/mips/sibyte/Kconfig +++ b/arch/mips/sibyte/Kconfig @@ -102,6 +102,14 @@ config SIMULATION Build a kernel suitable for running under the GDB simulator. Primarily adjusts the kernel's notion of time. +config CONFIG_SB1_CEX_ALWAYS_FATAL + bool "All cache exceptions considered fatal (no recovery attempted)" + depends on SIBYTE_SB1xxx_SOC + +config CONFIG_SB1_CERR_STALL + bool "Stall (rather than panic) on fatal cache error" + depends on SIBYTE_SB1xxx_SOC + config SIBYTE_CFE bool "Booting from CFE" depends on SIBYTE_SB1xxx_SOC -- 2.30.2