From 20d60d9973c3b441902b0a3f4f6f7e7ade08f77d Mon Sep 17 00:00:00 2001 From: "Maciej W. Rozycki" Date: Tue, 23 Oct 2007 12:43:11 +0100 Subject: [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 Signed-off-by: Ralf Baechle --- arch/mips/Kconfig | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) (limited to 'arch/mips/Kconfig') diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig index 12bf96334174..11bc17ce0ebf 100644 --- a/arch/mips/Kconfig +++ b/arch/mips/Kconfig @@ -91,6 +91,9 @@ config MACH_DECSTATION select BOOT_ELF32 select CEVT_R4K select CSRC_R4K + select CPU_DADDI_WORKAROUNDS if 64BIT + select CPU_R4000_WORKAROUNDS if 64BIT + select CPU_R4400_WORKAROUNDS if 64BIT select DMA_NONCOHERENT select NO_IOPORT select IRQ_CPU @@ -1605,6 +1608,19 @@ config CPU_HAS_SYNC config GENERIC_CLOCKEVENTS_BROADCAST bool +# +# CPU non-features +# +config CPU_DADDI_WORKAROUNDS + bool + +config CPU_R4000_WORKAROUNDS + bool + select CPU_R4400_WORKAROUNDS + +config CPU_R4400_WORKAROUNDS + bool + # # Use the generic interrupt handling code in kernel/irq/: # -- cgit v1.2.1