path: root/arch/mips/lib/strncpy_user.S
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authorMaciej W. Rozycki <macro@linux-mips.org>2007-10-23 12:43:11 +0100
committerRalf Baechle <ralf@linux-mips.org>2008-01-29 10:14:54 +0000
commit20d60d9973c3b441902b0a3f4f6f7e7ade08f77d (patch)
tree2dbadcb5600fcb486612ec30d972e6c29195ee1d /arch/mips/lib/strncpy_user.S
parent2b22c034d04d3632a339d14d5803c8f94e412608 (diff)
[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>
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