This reverts commit 97475f8b42e83be2966aa2d70ab9c98477701c53 (lmo) /
82b89152f0 (kernel.org) [MIPS: LD/SD o32
macro GAS fix update].
Turns out this patch is producing many build errors with gcc 4.2. Based
on further testing with a test case extracted from the build errors found
further build errors and suboptimal generation even in violation of the
"R" constraint.
To make matters worse, the binutils changes also don't work quite as
intended so revert this patch for now.
I am about to commit:
http://sourceware.org/ml/binutils/2010-10/msg00033.html
that fixes a problem with the LD/SD macro currently implemented by GAS for
the o32 ABI in an inconsistent way. This is best illustrated with a
simple program, which I'm copying here from the message above for easier
reference:
$ cat ld.s
ld $5,32767($4)
ld $5,32768($4)
This gets assebled into the following output:
$ mips-linux-as -32 -mips3 -o ld.o ld.s
$ mips-linux-objdump -d ld.o
ld.o: file format elf32-tradbigmips
Disassembly of section .text:
00000000 <.text>:
0: dc857fff ld a1,32767(a0)
4: 3c010001 lui at,0x1
8: 00810821 addu at,a0,at
c: 8c258000 lw a1,-32768(at)
10: 8c268004 lw a2,-32764(at)
...
Oops!
The GAS fix makes the macro behave in a consistent way and pairs of LW/SW
instructions to be output as appropriate regardless of the size of the
offset associated with the address used. The machine instruction is still
available, but to reach it macros have to be disabled first. This has a
side effect of requiring the use of a machine-addressable memory operand.
As some platforms require 64-bit operations for accesses to some I/O
registers LD/SD instructions are used in a couple of places in Linux
regardless of the ABI selected. Here's a fix for some pieces of code
affected I've been able to track down. The fix should be backwards
compatible with all supported binutils releases in existence and can be
used as a reference for any other places or off-tree code. The use of the
"R" constraint guarantees a machine-addressable operand.
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/1680/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
MIPS currently lacks the readl_be and writel_be accessors
which are required by BCM63xx for OHCI and EHCI support.
Let's define them globally for MIPS. This also fixes the
compilation of the bcm63xx defconfig against USB.
Signed-off-by: Florian Fainelli <ffainelli@freebox.fr>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: linux-mips@linux-mips.org
Cc: Maxime Bizon <mbizon@freebox.fr>
Patchwork: http://patchwork.linux-mips.org/patch/793/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
