[PATCH] Fix KMODE for the R3000

[PATCH] Fix KMODE for the R3000

[Maciej W. Rozycki]

 This must be the oldest bug that we have got.  Leaving interrupts "as 
they are" for the R3000 obviously means copying IEp to IEc.  Since we have 
got STATMASK now, I took this opportunity to mask the status register 
"correctly" for the R3000 now too.  Oh, and the R3000 hardly ever is 
64-bit.

Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
---
 The KMODE change is important, the others -- not so much, but I have 
thought there is not much point in separating these into three patches -- 
they are just too trivial.  Call them "R3000 fixes for <asm/stackframe.h>" 
if you like instead.

 Please apply.

  Maciej

patch-mips-2.6.18-20060920-r3000-kmode-2
diff -up --recursive --new-file linux-mips-2.6.18-20060920.macro/include/asm-mips/stackframe.h linux-mips-2.6.18-20060920/include/asm-mips/stackframe.h
--- linux-mips-2.6.18-20060920.macro/include/asm-mips/stackframe.h	2006-06-22 05:11:41.000000000 +0000
+++ linux-mips-2.6.18-20060920/include/asm-mips/stackframe.h	2007-05-21 00:03:57.000000000 +0000
@@ -17,6 +17,18 @@
 #include <asm/mipsregs.h>
 #include <asm/asm-offsets.h>
 
+/*
+ * For SMTC kernel, global IE should be left set, and interrupts
+ * controlled exclusively via IXMT.
+ */
+#ifdef CONFIG_MIPS_MT_SMTC
+#define STATMASK 0x1e
+#elif defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX)
+#define STATMASK 0x3f
+#else
+#define STATMASK 0x1f
+#endif
+
 #ifdef CONFIG_MIPS_MT_SMTC
 #include <asm/mipsmtregs.h>
 #endif /* CONFIG_MIPS_MT_SMTC */
@@ -244,10 +256,10 @@
 		.set	reorder
 		.set	noat
 		mfc0	a0, CP0_STATUS
-		ori	a0, 0x1f
-		xori	a0, 0x1f
-		mtc0	a0, CP0_STATUS
 		li	v1, 0xff00
+		ori	a0, STATMASK
+		xori	a0, STATMASK
+		mtc0	a0, CP0_STATUS
 		and	a0, v1
 		LONG_L	v0, PT_STATUS(sp)
 		nor	v1, $0, v1
@@ -257,10 +269,6 @@
 		LONG_L	$31, PT_R31(sp)
 		LONG_L	$28, PT_R28(sp)
 		LONG_L	$25, PT_R25(sp)
-#ifdef CONFIG_64BIT
-		LONG_L	$8, PT_R8(sp)
-		LONG_L	$9, PT_R9(sp)
-#endif
 		LONG_L	$7,  PT_R7(sp)
 		LONG_L	$6,  PT_R6(sp)
 		LONG_L	$5,  PT_R5(sp)
@@ -281,16 +289,6 @@
 		.endm
 
 #else
-/*
- * For SMTC kernel, global IE should be left set, and interrupts
- * controlled exclusively via IXMT.
- */
-
-#ifdef CONFIG_MIPS_MT_SMTC
-#define STATMASK 0x1e
-#else
-#define STATMASK 0x1f
-#endif
 		.macro	RESTORE_SOME
 		.set	push
 		.set	reorder
@@ -393,9 +391,9 @@
 		.macro	CLI
 #if !defined(CONFIG_MIPS_MT_SMTC)
 		mfc0	t0, CP0_STATUS
-		li	t1, ST0_CU0 | 0x1f
+		li	t1, ST0_CU0 | STATMASK
 		or	t0, t1
-		xori	t0, 0x1f
+		xori	t0, STATMASK
 		mtc0	t0, CP0_STATUS
 #else /* CONFIG_MIPS_MT_SMTC */
 		/*
@@ -428,9 +426,9 @@
 		.macro	STI
 #if !defined(CONFIG_MIPS_MT_SMTC)
 		mfc0	t0, CP0_STATUS
-		li	t1, ST0_CU0 | 0x1f
+		li	t1, ST0_CU0 | STATMASK
 		or	t0, t1
-		xori	t0, 0x1e
+		xori	t0, STATMASK & ~1
 		mtc0	t0, CP0_STATUS
 #else /* CONFIG_MIPS_MT_SMTC */
 		/*
@@ -459,7 +457,8 @@
 		.endm
 
 /*
- * Just move to kernel mode and leave interrupts as they are.
+ * Just move to kernel mode and leave interrupts as they are.  Note
+ * for the R3000 this means copying the previous enable from IEp.
  * Set cp0 enable bit as sign that we're running on the kernel stack
  */
 		.macro	KMODE
@@ -490,9 +489,14 @@
 		move	ra, t0
 #endif /* CONFIG_MIPS_MT_SMTC */
 		mfc0	t0, CP0_STATUS
-		li	t1, ST0_CU0 | 0x1e
+		li	t1, ST0_CU0 | (STATMASK & ~1)
+#if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX)
+		andi	t2, t0, ST0_IEP
+		srl	t2, 2
+		or	t0, t2
+#endif
 		or	t0, t1
-		xori	t0, 0x1e
+		xori	t0, STATMASK & ~1
 		mtc0	t0, CP0_STATUS
 #ifdef CONFIG_MIPS_MT_SMTC
 		_ehb

Re: [PATCH] Fix KMODE for the R3000

[Ralf Baechle]

On Mon, May 21, 2007 at 01:47:22PM +0100, Maciej W. Rozycki wrote:

>  This must be the oldest bug that we have got.  Leaving interrupts "as 
> they are" for the R3000 obviously means copying IEp to IEc.  Since we have 
> got STATMASK now, I took this opportunity to mask the status register 
> "correctly" for the R3000 now too.  Oh, and the R3000 hardly ever is 
> 64-bit.

Applied.

  Ralf