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authorMaciej W. Rozycki <macro@linux-mips.org>2007-10-23 12:43:11 +0100
committerRalf Baechle <ralf@linux-mips.org>2008-01-29 10:14:54 +0000
commit20d60d9973c3b441902b0a3f4f6f7e7ade08f77d (patch)
tree2dbadcb5600fcb486612ec30d972e6c29195ee1d /include/asm-mips/bugs.h
parent2b22c034d04d3632a339d14d5803c8f94e412608 (diff)
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[MIPS] R4000/R4400 errata workarounds
This is the gereric part of R4000/R4400 errata workarounds. They include compiler and assembler support as well as some source code modifications to address the problems with some combinations of multiply/divide+shift instructions as well as the daddi and daddiu instructions. Changes included are as follows: 1. New Kconfig options to select workarounds by platforms as necessary. 2. Arch top-level Makefile to pass necessary options to the compiler; also incompatible configurations are detected (-mno-sym32 unsupported as horribly intrusive for little gain). 3. Bug detection updated and shuffled -- the multiply/divide+shift problem is lethal enough that if not worked around it makes the kernel crash in time_init() because of a division by zero; the daddiu erratum might also trigger early potentially, though I have not observed it. On the other hand the daddi detection code requires the exception subsystem to have been initialised (and is there mainly for information). 4. r4k_daddiu_bug() added so that the existence of the erratum can be queried by code at the run time as necessary; useful for generated code like TLB fault and copy/clear page handlers. 5. __udelay() updated as it uses multiplication in inline assembly. Note that -mdaddi requires modified toolchain (which has been maintained by myself and available from my site for ~4years now -- versions covered are GCC 2.95.4 - 4.1.2 and binutils from 2.13 onwards). The -mfix-r4000 and -mfix-r4400 have been standard for a while though. 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/bugs.h')
-rw-r--r--include/asm-mips/bugs.h25
1 files changed, 25 insertions, 0 deletions
diff --git a/include/asm-mips/bugs.h b/include/asm-mips/bugs.h
index 0d7f9c1f5546..9dc10df32078 100644
--- a/include/asm-mips/bugs.h
+++ b/include/asm-mips/bugs.h
@@ -1,19 +1,34 @@
/*
* This is included by init/main.c to check for architecture-dependent bugs.
*
+ * Copyright (C) 2007 Maciej W. Rozycki
+ *
* Needs:
* void check_bugs(void);
*/
#ifndef _ASM_BUGS_H
#define _ASM_BUGS_H
+#include <linux/bug.h>
#include <linux/delay.h>
+
#include <asm/cpu.h>
#include <asm/cpu-info.h>
+extern int daddiu_bug;
+
+extern void check_bugs64_early(void);
+
extern void check_bugs32(void);
extern void check_bugs64(void);
+static inline void check_bugs_early(void)
+{
+#ifdef CONFIG_64BIT
+ check_bugs64_early();
+#endif
+}
+
static inline void check_bugs(void)
{
unsigned int cpu = smp_processor_id();
@@ -25,4 +40,14 @@ static inline void check_bugs(void)
#endif
}
+static inline int r4k_daddiu_bug(void)
+{
+#ifdef CONFIG_64BIT
+ WARN_ON(daddiu_bug < 0);
+ return daddiu_bug != 0;
+#else
+ return 0;
+#endif
+}
+
#endif /* _ASM_BUGS_H */
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