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author | Maciej W. Rozycki <macro@linux-mips.org> | 2007-10-23 11:43:11 (GMT) |
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committer | Ralf Baechle <ralf@linux-mips.org> | 2008-01-29 10:14:54 (GMT) |
commit | 20d60d9973c3b441902b0a3f4f6f7e7ade08f77d (patch) | |
tree | 2dbadcb5600fcb486612ec30d972e6c29195ee1d /include/asm-mips/delay.h | |
parent | 2b22c034d04d3632a339d14d5803c8f94e412608 (diff) | |
download | linux-fsl-qoriq-20d60d9973c3b441902b0a3f4f6f7e7ade08f77d.tar.xz |
[MIPS] R4000/R4400 errata workarounds
This is the gereric part of R4000/R4400 errata workarounds. They include
compiler and assembler support as well as some source code modifications
to address the problems with some combinations of multiply/divide+shift
instructions as well as the daddi and daddiu instructions.
Changes included are as follows:
1. New Kconfig options to select workarounds by platforms as necessary.
2. Arch top-level Makefile to pass necessary options to the compiler; also
incompatible configurations are detected (-mno-sym32 unsupported as
horribly intrusive for little gain).
3. Bug detection updated and shuffled -- the multiply/divide+shift problem
is lethal enough that if not worked around it makes the kernel crash in
time_init() because of a division by zero; the daddiu erratum might
also trigger early potentially, though I have not observed it. On the
other hand the daddi detection code requires the exception subsystem to
have been initialised (and is there mainly for information).
4. r4k_daddiu_bug() added so that the existence of the erratum can be
queried by code at the run time as necessary; useful for generated code
like TLB fault and copy/clear page handlers.
5. __udelay() updated as it uses multiplication in inline assembly.
Note that -mdaddi requires modified toolchain (which has been maintained
by myself and available from my site for ~4years now -- versions covered
are GCC 2.95.4 - 4.1.2 and binutils from 2.13 onwards). The -mfix-r4000
and -mfix-r4400 have been standard for a while though.
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Diffstat (limited to 'include/asm-mips/delay.h')
-rw-r--r-- | include/asm-mips/delay.h | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/include/asm-mips/delay.h b/include/asm-mips/delay.h index fab3213..de5105d 100644 --- a/include/asm-mips/delay.h +++ b/include/asm-mips/delay.h @@ -6,13 +6,16 @@ * Copyright (C) 1994 by Waldorf Electronics * Copyright (C) 1995 - 2000, 01, 03 by Ralf Baechle * Copyright (C) 1999, 2000 Silicon Graphics, Inc. + * Copyright (C) 2007 Maciej W. Rozycki */ #ifndef _ASM_DELAY_H #define _ASM_DELAY_H #include <linux/param.h> #include <linux/smp.h> + #include <asm/compiler.h> +#include <asm/war.h> static inline void __delay(unsigned long loops) { @@ -50,7 +53,7 @@ static inline void __delay(unsigned long loops) static inline void __udelay(unsigned long usecs, unsigned long lpj) { - unsigned long lo; + unsigned long hi, lo; /* * The rates of 128 is rounded wrongly by the catchall case @@ -70,11 +73,16 @@ static inline void __udelay(unsigned long usecs, unsigned long lpj) : "=h" (usecs), "=l" (lo) : "r" (usecs), "r" (lpj) : GCC_REG_ACCUM); - else if (sizeof(long) == 8) + else if (sizeof(long) == 8 && !R4000_WAR) __asm__("dmultu\t%2, %3" : "=h" (usecs), "=l" (lo) : "r" (usecs), "r" (lpj) : GCC_REG_ACCUM); + else if (sizeof(long) == 8 && R4000_WAR) + __asm__("dmultu\t%3, %4\n\tmfhi\t%0" + : "=r" (usecs), "=h" (hi), "=l" (lo) + : "r" (usecs), "r" (lpj) + : GCC_REG_ACCUM); __delay(usecs); } |