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/Makefile | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) (limited to 'arch/mips/Makefile') diff --git a/arch/mips/Makefile b/arch/mips/Makefile index a1f8d8b96b03..a49127af33c8 100644 --- a/arch/mips/Makefile +++ b/arch/mips/Makefile @@ -141,6 +141,10 @@ cflags-$(CONFIG_CPU_R8000) += -march=r8000 -Wa,--trap cflags-$(CONFIG_CPU_R10000) += $(call cc-option,-march=r10000,-march=r8000) \ -Wa,--trap +cflags-$(CONFIG_CPU_R4000_WORKAROUNDS) += $(call cc-option,-mfix-r4000,) +cflags-$(CONFIG_CPU_R4400_WORKAROUNDS) += $(call cc-option,-mfix-r4400,) +cflags-$(CONFIG_CPU_DADDI_WORKAROUNDS) += $(call cc-option,-mno-daddi,) + ifdef CONFIG_CPU_SB1 ifdef CONFIG_SB1_PASS_1_WORKAROUNDS MODFLAGS += -msb1-pass1-workarounds @@ -602,9 +606,11 @@ ifdef CONFIG_64BIT endif endif - ifeq ($(KBUILD_SYM32), y) - ifeq ($(call cc-option-yn,-msym32), y) - cflags-y += -msym32 -DKBUILD_64BIT_SYM32 + ifeq ($(KBUILD_SYM32)$(call cc-option-yn,-msym32), yy) + cflags-y += -msym32 -DKBUILD_64BIT_SYM32 + else + ifeq ($(CONFIG_CPU_DADDI_WORKAROUNDS), y) + $(error CONFIG_CPU_DADDI_WORKAROUNDS unsupported without -msym32) endif endif endif -- cgit v1.2.3