Better interface to run uncached cache setup code.
Signed-off-by: Thiemo Seufer <ths@networkno.de>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/lib/Makefile b/arch/mips/lib/Makefile
index 0373034..cf12caf 100644
--- a/arch/mips/lib/Makefile
+++ b/arch/mips/lib/Makefile
@@ -2,8 +2,8 @@
# Makefile for MIPS-specific library files..
#
-lib-y += csum_partial_copy.o memcpy.o promlib.o \
- strlen_user.o strncpy_user.o strnlen_user.o
+lib-y += csum_partial_copy.o memcpy.o promlib.o strlen_user.o strncpy_user.o \
+ strnlen_user.o uncached.o
obj-y += iomap.o
diff --git a/arch/mips/lib/uncached.c b/arch/mips/lib/uncached.c
new file mode 100644
index 0000000..98ce89f
--- /dev/null
+++ b/arch/mips/lib/uncached.c
@@ -0,0 +1,76 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 2005 Thiemo Seufer
+ * Copyright (C) 2005 MIPS Technologies, Inc. All rights reserved.
+ * Author: Maciej W. Rozycki <macro@mips.com>
+ */
+
+#include <linux/init.h>
+
+#include <asm/addrspace.h>
+#include <asm/bug.h>
+
+#ifndef CKSEG2
+#define CKSEG2 CKSSEG
+#endif
+#ifndef TO_PHYS_MASK
+#define TO_PHYS_MASK -1
+#endif
+
+/*
+ * FUNC is executed in one of the uncached segments, depending on its
+ * original address as follows:
+ *
+ * 1. If the original address is in CKSEG0 or CKSEG1, then the uncached
+ * segment used is CKSEG1.
+ * 2. If the original address is in XKPHYS, then the uncached segment
+ * used is XKPHYS(2).
+ * 3. Otherwise it's a bug.
+ *
+ * The same remapping is done with the stack pointer. Stack handling
+ * works because we don't handle stack arguments or more complex return
+ * values, so we can avoid sharing the same stack area between a cached
+ * and the uncached mode.
+ */
+unsigned long __init run_uncached(void *func)
+{
+ register long sp __asm__("$sp");
+ register long ret __asm__("$2");
+ long lfunc = (long)func, ufunc;
+ long usp;
+
+ if (sp >= (long)CKSEG0 && sp < (long)CKSEG2)
+ usp = CKSEG1ADDR(sp);
+ else if ((long long)sp >= (long long)PHYS_TO_XKPHYS(0LL, 0) &&
+ (long long)sp < (long long)PHYS_TO_XKPHYS(8LL, 0))
+ usp = PHYS_TO_XKPHYS((long long)K_CALG_UNCACHED,
+ XKPHYS_TO_PHYS((long long)sp));
+ else {
+ BUG();
+ usp = sp;
+ }
+ if (lfunc >= (long)CKSEG0 && lfunc < (long)CKSEG2)
+ ufunc = CKSEG1ADDR(lfunc);
+ else if ((long long)lfunc >= (long long)PHYS_TO_XKPHYS(0LL, 0) &&
+ (long long)lfunc < (long long)PHYS_TO_XKPHYS(8LL, 0))
+ ufunc = PHYS_TO_XKPHYS((long long)K_CALG_UNCACHED,
+ XKPHYS_TO_PHYS((long long)lfunc));
+ else {
+ BUG();
+ ufunc = lfunc;
+ }
+
+ __asm__ __volatile__ (
+ " move $16, $sp\n"
+ " move $sp, %1\n"
+ " jalr %2\n"
+ " move $sp, $16"
+ : "=r" (ret)
+ : "r" (usp), "r" (ufunc)
+ : "$16", "$31");
+
+ return ret;
+}
diff --git a/arch/mips/mm/c-r4k.c b/arch/mips/mm/c-r4k.c
index 48d731c..b901473 100644
--- a/arch/mips/mm/c-r4k.c
+++ b/arch/mips/mm/c-r4k.c
@@ -26,6 +26,7 @@
#include <asm/system.h>
#include <asm/mmu_context.h>
#include <asm/war.h>
+#include <asm/cacheflush.h> /* for run_uncached() */
static unsigned long icache_size, dcache_size, scache_size;
@@ -1119,7 +1120,6 @@
return 1;
}
-typedef int (*probe_func_t)(unsigned long);
extern int r5k_sc_init(void);
extern int rm7k_sc_init(void);
@@ -1127,7 +1127,6 @@
{
struct cpuinfo_mips *c = ¤t_cpu_data;
unsigned int config = read_c0_config();
- probe_func_t probe_scache_kseg1;
int sc_present = 0;
/*
@@ -1140,8 +1139,7 @@
case CPU_R4000MC:
case CPU_R4400SC:
case CPU_R4400MC:
- probe_scache_kseg1 = (probe_func_t) (CKSEG1ADDR(&probe_scache));
- sc_present = probe_scache_kseg1(config);
+ sc_present = run_uncached(probe_scache);
if (sc_present)
c->options |= MIPS_CPU_CACHE_CDEX_S;
break;
diff --git a/arch/mips/mm/sc-rm7k.c b/arch/mips/mm/sc-rm7k.c
index 4e92f93..1df5aab 100644
--- a/arch/mips/mm/sc-rm7k.c
+++ b/arch/mips/mm/sc-rm7k.c
@@ -15,6 +15,7 @@
#include <asm/cacheops.h>
#include <asm/mipsregs.h>
#include <asm/processor.h>
+#include <asm/cacheflush.h> /* for run_uncached() */
/* Primary cache parameters. */
#define sc_lsize 32
@@ -96,25 +97,13 @@
}
/*
- * This function is executed in the uncached segment CKSEG1.
- * It must not touch the stack, because the stack pointer still points
- * into CKSEG0.
- *
- * Three options:
- * - Write it in assembly and guarantee that we don't use the stack.
- * - Disable caching for CKSEG0 before calling it.
- * - Pray that GCC doesn't randomly start using the stack.
- *
- * This being Linux, we obviously take the least sane of those options -
- * following DaveM's lead in c-r4k.c
- *
- * It seems we get our kicks from relying on unguaranteed behaviour in GCC
+ * This function is executed in uncached address space.
*/
static __init void __rm7k_sc_enable(void)
{
int i;
- set_c0_config(1 << 3); /* CONF_SE */
+ set_c0_config(R7K_CONF_SE);
write_c0_taglo(0);
write_c0_taghi(0);
@@ -127,24 +116,22 @@
".set mips0\n\t"
".set reorder"
:
- : "r" (KSEG0ADDR(i)), "i" (Index_Store_Tag_SD));
+ : "r" (CKSEG0ADDR(i)), "i" (Index_Store_Tag_SD));
}
}
static __init void rm7k_sc_enable(void)
{
- void (*func)(void) = (void *) KSEG1ADDR(&__rm7k_sc_enable);
-
- if (read_c0_config() & 0x08) /* CONF_SE */
+ if (read_c0_config() & R7K_CONF_SE)
return;
printk(KERN_INFO "Enabling secondary cache...");
- func();
+ run_uncached(__rm7k_sc_enable);
}
static void rm7k_sc_disable(void)
{
- clear_c0_config(1<<3); /* CONF_SE */
+ clear_c0_config(R7K_CONF_SE);
}
struct bcache_ops rm7k_sc_ops = {
@@ -164,7 +151,7 @@
printk(KERN_INFO "Secondary cache size %dK, linesize %d bytes.\n",
(scache_size >> 10), sc_lsize);
- if (!((config >> 3) & 1)) /* CONF_SE */
+ if (!(config & R7K_CONF_SE))
rm7k_sc_enable();
/*
diff --git a/include/asm-mips/cacheflush.h b/include/asm-mips/cacheflush.h
index 4213d2c..a18ba2e 100644
--- a/include/asm-mips/cacheflush.h
+++ b/include/asm-mips/cacheflush.h
@@ -90,4 +90,7 @@
#define ClearPageDcacheDirty(page) \
clear_bit(PG_dcache_dirty, &(page)->flags)
+/* Run kernel code uncached, useful for cache probing functions. */
+unsigned long __init run_uncached(void *func);
+
#endif /* _ASM_CACHEFLUSH_H */
diff --git a/include/asm-mips/mipsregs.h b/include/asm-mips/mipsregs.h
index 006354e..f3b0b41 100644
--- a/include/asm-mips/mipsregs.h
+++ b/include/asm-mips/mipsregs.h
@@ -433,6 +433,9 @@
#define R5K_CONF_SE (_ULCAST_(1) << 12)
#define R5K_CONF_SS (_ULCAST_(3) << 20)
+/* Bits specific to the RM7000. */
+#define R7K_CONF_SE (_ULCAST_(1) << 3)
+
/* Bits specific to the R10000. */
#define R10K_CONF_DN (_ULCAST_(3) << 3)
#define R10K_CONF_CT (_ULCAST_(1) << 5)
