diff --git a/arch/mips/lib/Makefile b/arch/mips/lib/Makefile index 037303412909..cf12caf80774 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 000000000000..98ce89f8068b --- /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 + */ + +#include + +#include +#include + +#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 48d731c2f08a..b90147399ea4 100644 --- a/arch/mips/mm/c-r4k.c +++ b/arch/mips/mm/c-r4k.c @@ -26,6 +26,7 @@ #include #include #include +#include /* for run_uncached() */ static unsigned long icache_size, dcache_size, scache_size; @@ -1119,7 +1120,6 @@ static int __init probe_scache(void) 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 @@ static void __init setup_scache(void) { 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 @@ static void __init setup_scache(void) 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 4e92f931aaba..1df5aab82c13 100644 --- a/arch/mips/mm/sc-rm7k.c +++ b/arch/mips/mm/sc-rm7k.c @@ -15,6 +15,7 @@ #include #include #include +#include /* for run_uncached() */ /* Primary cache parameters. */ #define sc_lsize 32 @@ -96,25 +97,13 @@ static void rm7k_sc_inv(unsigned long addr, unsigned long size) } /* - * 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 @@ static __init void __rm7k_sc_enable(void) ".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 @@ void __init rm7k_sc_init(void) 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 4213d2c8bb8a..a18ba2edc0b6 100644 --- a/include/asm-mips/cacheflush.h +++ b/include/asm-mips/cacheflush.h @@ -90,4 +90,7 @@ extern void (*flush_data_cache_page)(unsigned long addr); #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 006354ed2e29..f3b0b4181508 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)