[PATCH 4/8] 8xx: Fixup DAR from buggy dcbX instructions.
scottwood at freescale.com
Thu Oct 15 04:20:03 EST 2009
On Sun, Oct 11, 2009 at 06:35:08PM +0200, Joakim Tjernlund wrote:
> This is an assembler version to fixup DAR not being set
> by dcbX, icbi instructions. There are two versions, one
> uses selfmodifing code, the other uses a
> jump table but is much bigger(default).
> arch/powerpc/kernel/head_8xx.S | 146 +++++++++++++++++++++++++++++++++++++++-
> 1 files changed, 145 insertions(+), 1 deletions(-)
> diff --git a/arch/powerpc/kernel/head_8xx.S b/arch/powerpc/kernel/head_8xx.S
> index 093176c..9839e79 100644
> --- a/arch/powerpc/kernel/head_8xx.S
> +++ b/arch/powerpc/kernel/head_8xx.S
> @@ -494,7 +494,8 @@ DataTLBError:
> mfspr r10, SPRN_DAR
> cmpwi cr0, r10, 0x00f0
> - beq- 2f /* must be a buggy dcbX, icbi insn. */
> + beq- FixDAR /* must be a buggy dcbX, icbi insn. */
> +DARFix: /* Return from dcbx instruction bug workaround, r10 holds value of DAR */
Both FixDAR and DARFix? Could we make the labels a little clearer?
> +/* This is the procedure to calculate the data EA for buggy dcbx,dcbi instructions
> + * by decoding the registers used by the dcbx instruction and adding them.
> + * DAR is set to the calculated address and r10 also holds the EA on exit.
> + */
How often does this happen? Could we just do it in C code after saving all
the registers, and avoid the self modifying stuff (or the big switch
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