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authorMaciej W. Rozycki <macro@linux-mips.org>2007-10-23 07:43:25 -0400
committerRalf Baechle <ralf@linux-mips.org>2008-01-29 05:14:55 -0500
commit619b6e18fce20e4b2d0082cde989f37e1be7b3e1 (patch)
treeb56120c0de584f6672aa7e4533163435613f5203 /include/asm-mips/stackframe.h
parent20d60d9973c3b441902b0a3f4f6f7e7ade08f77d (diff)
[MIPS] R4000/R4400 daddiu erratum workaround
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: Maciej W. Rozycki <macro@linux-mips.org> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Diffstat (limited to 'include/asm-mips/stackframe.h')
-rw-r--r--include/asm-mips/stackframe.h9
1 files changed, 9 insertions, 0 deletions
diff --git a/include/asm-mips/stackframe.h b/include/asm-mips/stackframe.h
index fb41a8d76392..051e1af0bb95 100644
--- a/include/asm-mips/stackframe.h
+++ b/include/asm-mips/stackframe.h
@@ -6,6 +6,7 @@
6 * Copyright (C) 1994, 95, 96, 99, 2001 Ralf Baechle 6 * Copyright (C) 1994, 95, 96, 99, 2001 Ralf Baechle
7 * Copyright (C) 1994, 1995, 1996 Paul M. Antoine. 7 * Copyright (C) 1994, 1995, 1996 Paul M. Antoine.
8 * Copyright (C) 1999 Silicon Graphics, Inc. 8 * Copyright (C) 1999 Silicon Graphics, Inc.
9 * Copyright (C) 2007 Maciej W. Rozycki
9 */ 10 */
10#ifndef _ASM_STACKFRAME_H 11#ifndef _ASM_STACKFRAME_H
11#define _ASM_STACKFRAME_H 12#define _ASM_STACKFRAME_H
@@ -145,8 +146,16 @@
145 .set reorder 146 .set reorder
146 /* Called from user mode, new stack. */ 147 /* Called from user mode, new stack. */
147 get_saved_sp 148 get_saved_sp
149#ifndef CONFIG_CPU_DADDI_WORKAROUNDS
1488: move k0, sp 1508: move k0, sp
149 PTR_SUBU sp, k1, PT_SIZE 151 PTR_SUBU sp, k1, PT_SIZE
152#else
153 .set at=k0
1548: PTR_SUBU k1, PT_SIZE
155 .set noat
156 move k0, sp
157 move sp, k1
158#endif
150 LONG_S k0, PT_R29(sp) 159 LONG_S k0, PT_R29(sp)
151 LONG_S $3, PT_R3(sp) 160 LONG_S $3, PT_R3(sp)
152 /* 161 /*