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  1. 29 Jan, 2008 6 commits
    • Maciej W. Rozycki's avatar
      [MIPS] R4000/R4400 daddiu erratum workaround · 619b6e18
      Maciej W. Rozycki authored 
       This complements the generic R4000/R4400 errata workaround code and adds 
bits for the daddiu problem.  In most places it just modifies handwritten 
assembly code so that the assembler is allowed to use a temporary register 
as daddiu may now be treated as a macro that expands to a sequence of li 
and daddu.  It is the AT register or, where AT is unavailable or used 
explicitly for another purpose, an explicitly-named register is selected, 
using the .set at=<reg> feature added recently to gas.  This feature is 
only used if CONFIG_CPU_DADDI_WORKAROUNDS has been set, so if the 
workaround remains disabled, the required version of binutils stays 
unchanged.

 Similarly, daddiu instructions put in branch delay slots in noreorder 
fragments are now taken out of them and the assembler is allowed to 
reorder them itself as possible (which it does making the whole idea of 
scheduling them into delay slots manually questionable).

 Also in the very few places where such a simple conversion was not 
possible, a handcoded longer sequence is implemented.

 Other than that there are changes to code responsible for building the 
TLB fault and page clear/copy handlers to avoid daddiu as appropriate.  
These are only effective if the erratum is verified to be present at the 
run time.

 Finally there is a trivial update to __delay(), because it uses daddiu in 
a branch delay slot.
Signed-off-by: default avatarMaciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
      619b6e18
    • Maciej W. Rozycki's avatar
      [MIPS] R4000/R4400 errata workarounds · 20d60d99
      Maciej W. Rozycki authored 
       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: default avatarMaciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
      20d60d99
    • Alejandro Martinez Ruiz's avatar
      [MIPS] Converting most array size calculations to use ARRAY_SIZE(). · 2b22c034
      Alejandro Martinez Ruiz authored 
      Signed-off-by: default avatarAlejandro Martinez Ruiz <alex@flawedcode.org>
Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
      2b22c034
    • Ralf Baechle's avatar
      [MIPS] tlbex: Cleanup handling of R2 hazards in TLB handlers. · 161548bf
      Ralf Baechle authored 
      Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
      161548bf
    • Ralf Baechle's avatar
      [MIPS] Delete unused CONFIG_64BIT_CONTEXT · 6920df40
      Ralf Baechle authored 
      The merge of the code to use this was never completed so delete it for the
time being.
Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
      6920df40
    • Ralf Baechle's avatar
      [MIPS] Delete unused CONFIG_DMA_IP32. · e414004e
      Ralf Baechle authored 
      The functionality of the former dma-ip32.c has been folded into
dma-default.c.
Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
      e414004e
  3. 28 Jan, 2008 34 commits
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