From 8ea2ddff41f795e3e9a0550612096b5115c593f1 Mon Sep 17 00:00:00 2001 From: Vineet Gupta Date: Thu, 4 Jun 2015 15:35:53 +0530 Subject: [PATCH] ARC: cacheflush: move some code around, delete old comments Signed-off-by: Vineet Gupta --- arch/arc/mm/cache.c | 267 +++++++++++++++++--------------------------- 1 file changed, 102 insertions(+), 165 deletions(-) diff --git a/arch/arc/mm/cache.c b/arch/arc/mm/cache.c index 322e11b3b1e3..1ed3430bc155 100644 --- a/arch/arc/mm/cache.c +++ b/arch/arc/mm/cache.c @@ -1,64 +1,12 @@ /* - * ARC700 VIPT Cache Management + * ARC Cache Management * + * Copyright (C) 2014-15 Synopsys, Inc. (www.synopsys.com) * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com) * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. - * - * vineetg: May 2011: for Non-aliasing VIPT D-cache following can be NOPs - * -flush_cache_dup_mm (fork) - * -likewise for flush_cache_mm (exit/execve) - * -likewise for flush_cache_range,flush_cache_page (munmap, exit, COW-break) - * - * vineetg: Apr 2011 - * -Now that MMU can support larger pg sz (16K), the determiniation of - * aliasing shd not be based on assumption of 8k pg - * - * vineetg: Mar 2011 - * -optimised version of flush_icache_range( ) for making I/D coherent - * when vaddr is available (agnostic of num of aliases) - * - * vineetg: Mar 2011 - * -Added documentation about I-cache aliasing on ARC700 and the way it - * was handled up until MMU V2. - * -Spotted a three year old bug when killing the 4 aliases, which needs - * bottom 2 bits, so we need to do paddr | {0x00, 0x01, 0x02, 0x03} - * instead of paddr | {0x00, 0x01, 0x10, 0x11} - * (Rajesh you owe me one now) - * - * vineetg: Dec 2010 - * -Off-by-one error when computing num_of_lines to flush - * This broke signal handling with bionic which uses synthetic sigret stub - * - * vineetg: Mar 2010 - * -GCC can't generate ZOL for core cache flush loops. - * Conv them into iterations based as opposed to while (start < end) types - * - * Vineetg: July 2009 - * -In I-cache flush routine we used to chk for aliasing for every line INV. - * Instead now we setup routines per cache geometry and invoke them - * via function pointers. - * - * Vineetg: Jan 2009 - * -Cache Line flush routines used to flush an extra line beyond end addr - * because check was while (end >= start) instead of (end > start) - * =Some call sites had to work around by doing -1, -4 etc to end param - * =Some callers didnt care. This was spec bad in case of INV routines - * which would discard valid data (cause of the horrible ext2 bug - * in ARC IDE driver) - * - * vineetg: June 11th 2008: Fixed flush_icache_range( ) - * -Since ARC700 caches are not coherent (I$ doesnt snoop D$) both need - * to be flushed, which it was not doing. - * -load_module( ) passes vmalloc addr (Kernel Virtual Addr) to the API, - * however ARC cache maintenance OPs require PHY addr. Thus need to do - * vmalloc_to_phy. - * -Also added optimisation there, that for range > PAGE SIZE we flush the - * entire cache in one shot rather than line by line. For e.g. a module - * with Code sz 600k, old code flushed 600k worth of cache (line-by-line), - * while cache is only 16 or 32k. */ #include @@ -142,54 +90,8 @@ dc_chk: } /* - * 1. Validate the Cache Geomtery (compile time config matches hardware) - * 2. If I-cache suffers from aliasing, setup work arounds (difft flush rtn) - * (aliasing D-cache configurations are not supported YET) - * 3. Enable the Caches, setup default flush mode for D-Cache - * 3. Calculate the SHMLBA used by user space + * Line Operation on {I,D}-Cache */ -void arc_cache_init(void) -{ - unsigned int __maybe_unused cpu = smp_processor_id(); - char str[256]; - - printk(arc_cache_mumbojumbo(0, str, sizeof(str))); - - if (IS_ENABLED(CONFIG_ARC_HAS_ICACHE)) { - struct cpuinfo_arc_cache *ic = &cpuinfo_arc700[cpu].icache; - - if (!ic->ver) - panic("cache support enabled but non-existent cache\n"); - - if (ic->line_len != L1_CACHE_BYTES) - panic("ICache line [%d] != kernel Config [%d]", - ic->line_len, L1_CACHE_BYTES); - - if (ic->ver != CONFIG_ARC_MMU_VER) - panic("Cache ver [%d] doesn't match MMU ver [%d]\n", - ic->ver, CONFIG_ARC_MMU_VER); - } - - if (IS_ENABLED(CONFIG_ARC_HAS_DCACHE)) { - struct cpuinfo_arc_cache *dc = &cpuinfo_arc700[cpu].dcache; - int handled; - - if (!dc->ver) - panic("cache support enabled but non-existent cache\n"); - - if (dc->line_len != L1_CACHE_BYTES) - panic("DCache line [%d] != kernel Config [%d]", - dc->line_len, L1_CACHE_BYTES); - - /* check for D-Cache aliasing */ - handled = IS_ENABLED(CONFIG_ARC_CACHE_VIPT_ALIASING); - - if (dc->alias && !handled) - panic("Enable CONFIG_ARC_CACHE_VIPT_ALIASING\n"); - else if (!dc->alias && handled) - panic("Don't need CONFIG_ARC_CACHE_VIPT_ALIASING\n"); - } -} #define OP_INV 0x1 #define OP_FLUSH 0x2 @@ -197,16 +99,55 @@ void arc_cache_init(void) #define OP_INV_IC 0x4 /* - * Common Helper for Line Operations on {I,D}-Cache + * I-Cache Aliasing in ARC700 VIPT caches (MMU v1-v3) + * + * ARC VIPT I-cache uses vaddr to index into cache and paddr to match the tag. + * The orig Cache Management Module "CDU" only required paddr to invalidate a + * certain line since it sufficed as index in Non-Aliasing VIPT cache-geometry. + * Infact for distinct V1,V2,P: all of {V1-P},{V2-P},{P-P} would end up fetching + * the exact same line. + * + * However for larger Caches (way-size > page-size) - i.e. in Aliasing config, + * paddr alone could not be used to correctly index the cache. + * + * ------------------ + * MMU v1/v2 (Fixed Page Size 8k) + * ------------------ + * The solution was to provide CDU with these additonal vaddr bits. These + * would be bits [x:13], x would depend on cache-geometry, 13 comes from + * standard page size of 8k. + * H/w folks chose [17:13] to be a future safe range, and moreso these 5 bits + * of vaddr could easily be "stuffed" in the paddr as bits [4:0] since the + * orig 5 bits of paddr were anyways ignored by CDU line ops, as they + * represent the offset within cache-line. The adv of using this "clumsy" + * interface for additional info was no new reg was needed in CDU programming + * model. + * + * 17:13 represented the max num of bits passable, actual bits needed were + * fewer, based on the num-of-aliases possible. + * -for 2 alias possibility, only bit 13 needed (32K cache) + * -for 4 alias possibility, bits 14:13 needed (64K cache) + * + * ------------------ + * MMU v3 + * ------------------ + * This ver of MMU supports variable page sizes (1k-16k): although Linux will + * only support 8k (default), 16k and 4k. + * However from hardware perspective, smaller page sizes aggrevate aliasing + * meaning more vaddr bits needed to disambiguate the cache-line-op ; + * the existing scheme of piggybacking won't work for certain configurations. + * Two new registers IC_PTAG and DC_PTAG inttoduced. + * "tag" bits are provided in PTAG, index bits in existing IVIL/IVDL/FLDL regs */ + static inline void __cache_line_loop(unsigned long paddr, unsigned long vaddr, - unsigned long sz, const int cacheop) + unsigned long sz, const int op) { unsigned int aux_cmd, aux_tag; int num_lines; const int full_page_op = __builtin_constant_p(sz) && sz == PAGE_SIZE; - if (cacheop == OP_INV_IC) { + if (op == OP_INV_IC) { aux_cmd = ARC_REG_IC_IVIL; #if (CONFIG_ARC_MMU_VER > 2) aux_tag = ARC_REG_IC_PTAG; @@ -214,7 +155,7 @@ static inline void __cache_line_loop(unsigned long paddr, unsigned long vaddr, } else { /* d$ cmd: INV (discard or wback-n-discard) OR FLUSH (wback) */ - aux_cmd = cacheop & OP_INV ? ARC_REG_DC_IVDL : ARC_REG_DC_FLDL; + aux_cmd = op & OP_INV ? ARC_REG_DC_IVDL : ARC_REG_DC_FLDL; #if (CONFIG_ARC_MMU_VER > 2) aux_tag = ARC_REG_DC_PTAG; #endif @@ -296,107 +237,60 @@ static inline void __after_dc_op(const int op, unsigned int reg) /* * Operation on Entire D-Cache - * @cacheop = {OP_INV, OP_FLUSH, OP_FLUSH_N_INV} + * @op = {OP_INV, OP_FLUSH, OP_FLUSH_N_INV} * Note that constant propagation ensures all the checks are gone * in generated code */ -static inline void __dc_entire_op(const int cacheop) +static inline void __dc_entire_op(const int op) { unsigned int ctrl_reg; int aux; - ctrl_reg = __before_dc_op(cacheop); + ctrl_reg = __before_dc_op(op); - if (cacheop & OP_INV) /* Inv or flush-n-inv use same cmd reg */ + if (op & OP_INV) /* Inv or flush-n-inv use same cmd reg */ aux = ARC_REG_DC_IVDC; else aux = ARC_REG_DC_FLSH; write_aux_reg(aux, 0x1); - __after_dc_op(cacheop, ctrl_reg); + __after_dc_op(op, ctrl_reg); } /* For kernel mappings cache operation: index is same as paddr */ #define __dc_line_op_k(p, sz, op) __dc_line_op(p, p, sz, op) /* - * D-Cache : Per Line INV (discard or wback+discard) or FLUSH (wback) + * D-Cache Line ops: Per Line INV (discard or wback+discard) or FLUSH (wback) */ static inline void __dc_line_op(unsigned long paddr, unsigned long vaddr, - unsigned long sz, const int cacheop) + unsigned long sz, const int op) { unsigned long flags; unsigned int ctrl_reg; local_irq_save(flags); - ctrl_reg = __before_dc_op(cacheop); + ctrl_reg = __before_dc_op(op); - __cache_line_loop(paddr, vaddr, sz, cacheop); + __cache_line_loop(paddr, vaddr, sz, op); - __after_dc_op(cacheop, ctrl_reg); + __after_dc_op(op, ctrl_reg); local_irq_restore(flags); } #else -#define __dc_entire_op(cacheop) -#define __dc_line_op(paddr, vaddr, sz, cacheop) -#define __dc_line_op_k(paddr, sz, cacheop) +#define __dc_entire_op(op) +#define __dc_line_op(paddr, vaddr, sz, op) +#define __dc_line_op_k(paddr, sz, op) #endif /* CONFIG_ARC_HAS_DCACHE */ - #ifdef CONFIG_ARC_HAS_ICACHE -/* - * I-Cache Aliasing in ARC700 VIPT caches - * - * ARC VIPT I-cache uses vaddr to index into cache and paddr to match the tag. - * The orig Cache Management Module "CDU" only required paddr to invalidate a - * certain line since it sufficed as index in Non-Aliasing VIPT cache-geometry. - * Infact for distinct V1,V2,P: all of {V1-P},{V2-P},{P-P} would end up fetching - * the exact same line. - * - * However for larger Caches (way-size > page-size) - i.e. in Aliasing config, - * paddr alone could not be used to correctly index the cache. - * - * ------------------ - * MMU v1/v2 (Fixed Page Size 8k) - * ------------------ - * The solution was to provide CDU with these additonal vaddr bits. These - * would be bits [x:13], x would depend on cache-geometry, 13 comes from - * standard page size of 8k. - * H/w folks chose [17:13] to be a future safe range, and moreso these 5 bits - * of vaddr could easily be "stuffed" in the paddr as bits [4:0] since the - * orig 5 bits of paddr were anyways ignored by CDU line ops, as they - * represent the offset within cache-line. The adv of using this "clumsy" - * interface for additional info was no new reg was needed in CDU programming - * model. - * - * 17:13 represented the max num of bits passable, actual bits needed were - * fewer, based on the num-of-aliases possible. - * -for 2 alias possibility, only bit 13 needed (32K cache) - * -for 4 alias possibility, bits 14:13 needed (64K cache) - * - * ------------------ - * MMU v3 - * ------------------ - * This ver of MMU supports variable page sizes (1k-16k): although Linux will - * only support 8k (default), 16k and 4k. - * However from hardware perspective, smaller page sizes aggrevate aliasing - * meaning more vaddr bits needed to disambiguate the cache-line-op ; - * the existing scheme of piggybacking won't work for certain configurations. - * Two new registers IC_PTAG and DC_PTAG inttoduced. - * "tag" bits are provided in PTAG, index bits in existing IVIL/IVDL/FLDL regs - */ - -/*********************************************************** - * Machine specific helper for per line I-Cache invalidate. - */ - static inline void __ic_entire_inv(void) { write_aux_reg(ARC_REG_IC_IVIC, 1); @@ -721,3 +615,46 @@ SYSCALL_DEFINE3(cacheflush, uint32_t, start, uint32_t, sz, uint32_t, flags) flush_cache_all(); return 0; } + +void arc_cache_init(void) +{ + unsigned int __maybe_unused cpu = smp_processor_id(); + char str[256]; + + printk(arc_cache_mumbojumbo(0, str, sizeof(str))); + + if (IS_ENABLED(CONFIG_ARC_HAS_ICACHE)) { + struct cpuinfo_arc_cache *ic = &cpuinfo_arc700[cpu].icache; + + if (!ic->ver) + panic("cache support enabled but non-existent cache\n"); + + if (ic->line_len != L1_CACHE_BYTES) + panic("ICache line [%d] != kernel Config [%d]", + ic->line_len, L1_CACHE_BYTES); + + if (ic->ver != CONFIG_ARC_MMU_VER) + panic("Cache ver [%d] doesn't match MMU ver [%d]\n", + ic->ver, CONFIG_ARC_MMU_VER); + } + + if (IS_ENABLED(CONFIG_ARC_HAS_DCACHE)) { + struct cpuinfo_arc_cache *dc = &cpuinfo_arc700[cpu].dcache; + int handled; + + if (!dc->ver) + panic("cache support enabled but non-existent cache\n"); + + if (dc->line_len != L1_CACHE_BYTES) + panic("DCache line [%d] != kernel Config [%d]", + dc->line_len, L1_CACHE_BYTES); + + /* check for D-Cache aliasing */ + handled = IS_ENABLED(CONFIG_ARC_CACHE_VIPT_ALIASING); + + if (dc->alias && !handled) + panic("Enable CONFIG_ARC_CACHE_VIPT_ALIASING\n"); + else if (!dc->alias && handled) + panic("Disable CONFIG_ARC_CACHE_VIPT_ALIASING\n"); + } +} -- 2.30.2