[MIPS] Add basic SMARTMIPS ASE support

This patch adds trivial support for SMARTMIPS extension. This extension
is currently implemented by 4KS[CD] CPUs.

Basically it saves/restores ACX register, which is part of the SMARTMIPS
ASE, when needed. This patch does *not* add any support for Smartmips MMU
features.

Futhermore this patch does not add explicit support for 4KS[CD] CPUs since
they are respectively mips32 and mips32r2 compliant.  So with the current
processor configuration, a platform that has such CPUs needs to select
both configs:

	CPU_HAS_SMARTMIPS
	SYS_HAS_CPU_MIPS32_R[12]

This is due to the processor configuration which is mixing up all the
architecture variants and the processor types.

The drawback of this, is that we currently pass '-march=mips32' option to
gcc when building a kernel instead of '-march=4ksc' for 4KSC case. This
can lead to a kernel image a little bit bigger than required.

Signed-off-by: Franck Bui-Huu <fbuihuu@gmail.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 4 insertions, 0 deletions

diff --git a/include/asm-mips/ptrace.h b/include/asm-mips/ptrace.h
index 8a1f2b6f04a..1906938285c 100644
--- a/include/asm-mips/ptrace.h
+++ b/include/asm-mips/ptrace.h
@@ -21,6 +21,7 @@
 #define FPC_EIR		70
 #define DSP_BASE	71		/* 3 more hi / lo register pairs */
 #define DSP_CONTROL	77
+#define ACX		78
 
 /*
  * This struct defines the way the registers are stored on the stack during a
@@ -39,6 +40,9 @@ struct pt_regs {
 	unsigned long cp0_status;
 	unsigned long hi;
 	unsigned long lo;
+#ifdef CONFIG_CPU_HAS_SMARTMIPS
+	unsigned long acx;
+#endif
 	unsigned long cp0_badvaddr;
 	unsigned long cp0_cause;
 	unsigned long cp0_epc;