diff options
| -rw-r--r-- | arch/arc/include/asm/arcregs.h | 80 | ||||
| -rw-r--r-- | arch/arc/include/asm/cache.h | 54 | ||||
| -rw-r--r-- | arch/arc/include/asm/cachectl.h | 28 | ||||
| -rw-r--r-- | arch/arc/include/asm/cacheflush.h | 67 | ||||
| -rw-r--r-- | arch/arc/mm/cache_arc700.c | 725 |
5 files changed, 954 insertions, 0 deletions
diff --git a/arch/arc/include/asm/arcregs.h b/arch/arc/include/asm/arcregs.h index 5131bb3d4fcd..c6e28053fb70 100644 --- a/arch/arc/include/asm/arcregs.h +++ b/arch/arc/include/asm/arcregs.h @@ -58,6 +58,33 @@ #define TIMER_CTRL_IE (1 << 0) /* Interupt when Count reachs limit */ #define TIMER_CTRL_NH (1 << 1) /* Count only when CPU NOT halted */ +/* Instruction cache related Auxiliary registers */ +#define ARC_REG_IC_BCR 0x77 /* Build Config reg */ +#define ARC_REG_IC_IVIC 0x10 +#define ARC_REG_IC_CTRL 0x11 +#define ARC_REG_IC_IVIL 0x19 +#if (CONFIG_ARC_MMU_VER > 2) +#define ARC_REG_IC_PTAG 0x1E +#endif + +/* Bit val in IC_CTRL */ +#define IC_CTRL_CACHE_DISABLE 0x1 + +/* Data cache related Auxiliary registers */ +#define ARC_REG_DC_BCR 0x72 +#define ARC_REG_DC_IVDC 0x47 +#define ARC_REG_DC_CTRL 0x48 +#define ARC_REG_DC_IVDL 0x4A +#define ARC_REG_DC_FLSH 0x4B +#define ARC_REG_DC_FLDL 0x4C +#if (CONFIG_ARC_MMU_VER > 2) +#define ARC_REG_DC_PTAG 0x5C +#endif + +/* Bit val in DC_CTRL */ +#define DC_CTRL_INV_MODE_FLUSH 0x40 +#define DC_CTRL_FLUSH_STATUS 0x100 + /* * Floating Pt Registers * Status regs are read-only (build-time) so need not be saved/restored @@ -132,6 +159,31 @@ #endif +#define READ_BCR(reg, into) \ +{ \ + unsigned int tmp; \ + tmp = read_aux_reg(reg); \ + if (sizeof(tmp) == sizeof(into)) { \ + into = *((typeof(into) *)&tmp); \ + } else { \ + extern void bogus_undefined(void); \ + bogus_undefined(); \ + } \ +} + +#define WRITE_BCR(reg, into) \ +{ \ + unsigned int tmp; \ + if (sizeof(tmp) == sizeof(into)) { \ + tmp = (*(unsigned int *)(into)); \ + write_aux_reg(reg, tmp); \ + } else { \ + extern void bogus_undefined(void); \ + bogus_undefined(); \ + } \ +} + + #ifdef CONFIG_ARC_FPU_SAVE_RESTORE /* These DPFP regs need to be saved/restored across ctx-sw */ struct arc_fpu { @@ -141,6 +193,34 @@ struct arc_fpu { }; #endif +/* + *************************************************************** + * Build Configuration Registers, with encoded hardware config + */ + +struct bcr_cache { +#ifdef CONFIG_CPU_BIG_ENDIAN + unsigned int pad:12, line_len:4, sz:4, config:4, ver:8; +#else + unsigned int ver:8, config:4, sz:4, line_len:4, pad:12; +#endif +}; + +/* + ******************************************************************* + * Generic structures to hold build configuration used at runtime + */ + +struct cpuinfo_arc_cache { + unsigned int has_aliasing, sz, line_len, assoc, ver; +}; + +struct cpuinfo_arc { + struct cpuinfo_arc_cache icache, dcache; +}; + +extern struct cpuinfo_arc cpuinfo_arc700[]; + #endif /* __ASEMBLY__ */ #endif /* __KERNEL__ */ diff --git a/arch/arc/include/asm/cache.h b/arch/arc/include/asm/cache.h index 30c72a4d2d9f..6632273861fd 100644 --- a/arch/arc/include/asm/cache.h +++ b/arch/arc/include/asm/cache.h @@ -18,4 +18,58 @@ #define L1_CACHE_BYTES (1 << L1_CACHE_SHIFT) +#define ARC_ICACHE_WAYS 2 +#define ARC_DCACHE_WAYS 4 + +/* Helpers */ +#define ARC_ICACHE_LINE_LEN L1_CACHE_BYTES +#define ARC_DCACHE_LINE_LEN L1_CACHE_BYTES + +#define ICACHE_LINE_MASK (~(ARC_ICACHE_LINE_LEN - 1)) +#define DCACHE_LINE_MASK (~(ARC_DCACHE_LINE_LEN - 1)) + +#if ARC_ICACHE_LINE_LEN != ARC_DCACHE_LINE_LEN +#error "Need to fix some code as I/D cache lines not same" +#else +#define is_not_cache_aligned(p) ((unsigned long)p & (~DCACHE_LINE_MASK)) +#endif + +#ifndef __ASSEMBLY__ + +/* Uncached access macros */ +#define arc_read_uncached_32(ptr) \ +({ \ + unsigned int __ret; \ + __asm__ __volatile__( \ + " ld.di %0, [%1] \n" \ + : "=r"(__ret) \ + : "r"(ptr)); \ + __ret; \ +}) + +#define arc_write_uncached_32(ptr, data)\ +({ \ + __asm__ __volatile__( \ + " st.di %0, [%1] \n" \ + : \ + : "r"(data), "r"(ptr)); \ +}) + +/* used to give SHMLBA a value to avoid Cache Aliasing */ +extern unsigned int ARC_shmlba; + +#define ARCH_DMA_MINALIGN L1_CACHE_BYTES + +/* + * ARC700 doesn't cache any access in top 256M. + * Ideal for wiring memory mapped peripherals as we don't need to do + * explicit uncached accesses (LD.di/ST.di) hence more portable drivers + */ +#define ARC_UNCACHED_ADDR_SPACE 0xc0000000 + +extern void arc_cache_init(void); +extern char *arc_cache_mumbojumbo(int cpu_id, char *buf, int len); +extern void __init read_decode_cache_bcr(void); +#endif + #endif /* _ASM_CACHE_H */ diff --git a/arch/arc/include/asm/cachectl.h b/arch/arc/include/asm/cachectl.h new file mode 100644 index 000000000000..51c73f0255b3 --- /dev/null +++ b/arch/arc/include/asm/cachectl.h @@ -0,0 +1,28 @@ +/* + * 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. + */ + +#ifndef __ARC_ASM_CACHECTL_H +#define __ARC_ASM_CACHECTL_H + +/* + * ARC ABI flags defined for Android's finegrained cacheflush requirements + */ +#define CF_I_INV 0x0002 +#define CF_D_FLUSH 0x0010 +#define CF_D_FLUSH_INV 0x0020 + +#define CF_DEFAULT (CF_I_INV | CF_D_FLUSH) + +/* + * Standard flags expected by cacheflush system call users + */ +#define ICACHE CF_I_INV +#define DCACHE CF_D_FLUSH +#define BCACHE (CF_I_INV | CF_D_FLUSH) + +#endif diff --git a/arch/arc/include/asm/cacheflush.h b/arch/arc/include/asm/cacheflush.h new file mode 100644 index 000000000000..97ee96f26505 --- /dev/null +++ b/arch/arc/include/asm/cacheflush.h @@ -0,0 +1,67 @@ +/* + * 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,page} (munmap, exit, COW-break) + * + * vineetg: April 2008 + * -Added a critical CacheLine flush to copy_to_user_page( ) which + * was causing gdbserver to not setup breakpoints consistently + */ + +#ifndef _ASM_CACHEFLUSH_H +#define _ASM_CACHEFLUSH_H + +#include <linux/mm.h> + +void flush_cache_all(void); + +void flush_icache_range(unsigned long start, unsigned long end); +void flush_icache_page(struct vm_area_struct *vma, struct page *page); +void flush_icache_range_vaddr(unsigned long paddr, unsigned long u_vaddr, + int len); + +#define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE 1 + +void flush_dcache_page(struct page *page); + +void dma_cache_wback_inv(unsigned long start, unsigned long sz); +void dma_cache_inv(unsigned long start, unsigned long sz); +void dma_cache_wback(unsigned long start, unsigned long sz); + +#define flush_dcache_mmap_lock(mapping) do { } while (0) +#define flush_dcache_mmap_unlock(mapping) do { } while (0) + +/* TBD: optimize this */ +#define flush_cache_vmap(start, end) flush_cache_all() +#define flush_cache_vunmap(start, end) flush_cache_all() + +/* + * VM callbacks when entire/range of user-space V-P mappings are + * torn-down/get-invalidated + * + * Currently we don't support D$ aliasing configs for our VIPT caches + * NOPS for VIPT Cache with non-aliasing D$ configurations only + */ +#define flush_cache_dup_mm(mm) /* called on fork */ +#define flush_cache_mm(mm) /* called on munmap/exit */ +#define flush_cache_range(mm, u_vstart, u_vend) +#define flush_cache_page(vma, u_vaddr, pfn) /* PF handling/COW-break */ + +#define copy_to_user_page(vma, page, vaddr, dst, src, len) \ +do { \ + memcpy(dst, src, len); \ + if (vma->vm_flags & VM_EXEC) \ + flush_icache_range_vaddr((unsigned long)(dst), vaddr, len);\ +} while (0) + +#define copy_from_user_page(vma, page, vaddr, dst, src, len) \ + memcpy(dst, src, len); \ + +#endif diff --git a/arch/arc/mm/cache_arc700.c b/arch/arc/mm/cache_arc700.c new file mode 100644 index 000000000000..670f65bb2ef1 --- /dev/null +++ b/arch/arc/mm/cache_arc700.c @@ -0,0 +1,725 @@ +/* + * ARC700 VIPT Cache Management + * + * 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 <linux/module.h> +#include <linux/mm.h> +#include <linux/sched.h> +#include <linux/cache.h> +#include <linux/mmu_context.h> +#include <linux/syscalls.h> +#include <linux/uaccess.h> +#include <asm/cacheflush.h> +#include <asm/cachectl.h> +#include <asm/setup.h> + + +#ifdef CONFIG_ARC_HAS_ICACHE +static void __ic_line_inv_no_alias(unsigned long, int); +static void __ic_line_inv_2_alias(unsigned long, int); +static void __ic_line_inv_4_alias(unsigned long, int); + +/* Holds the ptr to flush routine, dependign on size due to aliasing issues */ +static void (*___flush_icache_rtn) (unsigned long, int); +#endif + +/* + * Read the Cache Build Confuration Registers, Decode them and save into + * the cpuinfo structure for later use. + * No Validation done here, simply read/convert the BCRs + */ +void __init read_decode_cache_bcr(void) +{ + struct bcr_cache ibcr, dbcr; + struct cpuinfo_arc_cache *p_ic, *p_dc; + unsigned int cpu = smp_processor_id(); + + p_ic = &cpuinfo_arc700[cpu].icache; + READ_BCR(ARC_REG_IC_BCR, ibcr); + + if (ibcr.config == 0x3) + p_ic->assoc = 2; + p_ic->line_len = 8 << ibcr.line_len; + p_ic->sz = 0x200 << ibcr.sz; + p_ic->ver = ibcr.ver; + + p_dc = &cpuinfo_arc700[cpu].dcache; + READ_BCR(ARC_REG_DC_BCR, dbcr); + + if (dbcr.config == 0x2) + p_dc->assoc = 4; + p_dc->line_len = 16 << dbcr.line_len; + p_dc->sz = 0x200 << dbcr.sz; + p_dc->ver = dbcr.ver; +} + +/* + * 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 + */ +void __init arc_cache_init(void) +{ + unsigned int temp; +#ifdef CONFIG_ARC_CACHE + unsigned int cpu = smp_processor_id(); +#endif +#ifdef CONFIG_ARC_HAS_ICACHE + struct cpuinfo_arc_cache *ic; +#endif +#ifdef CONFIG_ARC_HAS_DCACHE + struct cpuinfo_arc_cache *dc; +#endif + int way_pg_ratio = way_pg_ratio; + +#ifdef CONFIG_ARC_HAS_ICACHE + ic = &cpuinfo_arc700[cpu].icache; + + /* + * if Cache way size is <= page size then no aliasing exhibited + * otherwise ratio determines num of aliases. + * e.g. 32K I$, 2 way set assoc, 8k pg size + * way-sz = 32k/2 = 16k + * way-pg-ratio = 16k/8k = 2, so 2 aliases possible + * (meaning 1 line could be in 2 possible locations). + */ + way_pg_ratio = ic->sz / ARC_ICACHE_WAYS / PAGE_SIZE; + switch (way_pg_ratio) { + case 0: + case 1: + ___flush_icache_rtn = __ic_line_inv_no_alias; + break; + case 2: + ___flush_icache_rtn = __ic_line_inv_2_alias; + break; + case 4: + ___flush_icache_rtn = __ic_line_inv_4_alias; + break; + default: + panic("Unsupported I-Cache Sz\n"); + } +#endif + + /* Enable/disable I-Cache */ + temp = read_aux_reg(ARC_REG_IC_CTRL); + +#ifdef CONFIG_ARC_HAS_ICACHE + temp &= ~IC_CTRL_CACHE_DISABLE; +#else + temp |= IC_CTRL_CACHE_DISABLE; +#endif + + write_aux_reg(ARC_REG_IC_CTRL, temp); + +#ifdef CONFIG_ARC_HAS_DCACHE + dc = &cpuinfo_arc700[cpu].dcache; + + /* check for D-Cache aliasing */ + if ((dc->sz / ARC_DCACHE_WAYS) > PAGE_SIZE) + panic("D$ aliasing not handled right now\n"); +#endif + + /* Set the default Invalidate Mode to "simpy discard dirty lines" + * as this is more frequent then flush before invalidate + * Ofcourse we toggle this default behviour when desired + */ + temp = read_aux_reg(ARC_REG_DC_CTRL); + temp &= ~DC_CTRL_INV_MODE_FLUSH; + +#ifdef CONFIG_ARC_HAS_DCACHE + /* Enable D-Cache: Clear Bit 0 */ + write_aux_reg(ARC_REG_DC_CTRL, temp & ~IC_CTRL_CACHE_DISABLE); +#else + /* Flush D cache */ + write_aux_reg(ARC_REG_DC_FLSH, 0x1); + /* Disable D cache */ + write_aux_reg(ARC_REG_DC_CTRL, temp | IC_CTRL_CACHE_DISABLE); +#endif + + return; +} + +#define OP_INV 0x1 +#define OP_FLUSH 0x2 +#define OP_FLUSH_N_INV 0x3 + +#ifdef CONFIG_ARC_HAS_DCACHE + +/*************************************************************** + * Machine specific helpers for Entire D-Cache or Per Line ops + */ + +static inline void wait_for_flush(void) +{ + while (read_aux_reg(ARC_REG_DC_CTRL) & DC_CTRL_FLUSH_STATUS) + ; +} + +/* + * Operation on Entire D-Cache + * @cacheop = {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) +{ + unsigned long flags, tmp = tmp; + int aux; + + local_irq_save(flags); + + if (cacheop == OP_FLUSH_N_INV) { + /* Dcache provides 2 cmd: FLUSH or INV + * INV inturn has sub-modes: DISCARD or FLUSH-BEFORE + * flush-n-inv is achieved by INV cmd but with IM=1 + * Default INV sub-mode is DISCARD, which needs to be toggled + */ + tmp = read_aux_reg(ARC_REG_DC_CTRL); + write_aux_reg(ARC_REG_DC_CTRL, tmp | DC_CTRL_INV_MODE_FLUSH); + } + + if (cacheop & 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); + + if (cacheop & OP_FLUSH) /* flush / flush-n-inv both wait */ + wait_for_flush(); + + /* Switch back the DISCARD ONLY Invalidate mode */ + if (cacheop == OP_FLUSH_N_INV) + write_aux_reg(ARC_REG_DC_CTRL, tmp & ~DC_CTRL_INV_MODE_FLUSH); + + local_irq_restore(flags); +} + +/* + * Per Line Operation on D-Cache + * Doesn't deal with type-of-op/IRQ-disabling/waiting-for-flush-to-complete + * It's sole purpose is to help gcc generate ZOL + */ +static inline void __dc_line_loop(unsigned long start, unsigned long sz, + int aux_reg) +{ + int num_lines, slack; + + /* Ensure we properly floor/ceil the non-line aligned/sized requests + * and have @start - aligned to cache line and integral @num_lines. + * This however can be avoided for page sized since: + * -@start will be cache-line aligned already (being page aligned) + * -@sz will be integral multiple of line size (being page sized). + */ + if (!(__builtin_constant_p(sz) && sz == PAGE_SIZE)) { + slack = start & ~DCACHE_LINE_MASK; + sz += slack; + start -= slack; + } + + num_lines = DIV_ROUND_UP(sz, ARC_DCACHE_LINE_LEN); + + while (num_lines-- > 0) { +#if (CONFIG_ARC_MMU_VER > 2) + /* + * Just as for I$, in MMU v3, D$ ops also require + * "tag" bits in DC_PTAG, "index" bits in FLDL,IVDL ops + * But we pass phy addr for both. This works since Linux + * doesn't support aliasing configs for D$, yet. + * Thus paddr is enough to provide both tag and index. + */ + write_aux_reg(ARC_REG_DC_PTAG, start); +#endif + write_aux_reg(aux_reg, start); + start += ARC_DCACHE_LINE_LEN; + } +} + +/* + * D-Cache : Per Line INV (discard or wback+discard) or FLUSH (wback) + */ +static inline void __dc_line_op(unsigned long start, unsigned long sz, + const int cacheop) +{ + unsigned long flags, tmp = tmp; + int aux; + + local_irq_save(flags); + + if (cacheop == OP_FLUSH_N_INV) { + /* + * Dcache provides 2 cmd: FLUSH or INV + * INV inturn has sub-modes: DISCARD or FLUSH-BEFORE + * flush-n-inv is achieved by INV cmd but with IM=1 + * Default INV sub-mode is DISCARD, which needs to be toggled + */ + tmp = read_aux_reg(ARC_REG_DC_CTRL); + write_aux_reg(ARC_REG_DC_CTRL, tmp | DC_CTRL_INV_MODE_FLUSH); + } + + if (cacheop & OP_INV) /* Inv / flush-n-inv use same cmd reg */ + aux = ARC_REG_DC_IVDL; + else + aux = ARC_REG_DC_FLDL; + + __dc_line_loop(start, sz, aux); + + if (cacheop & OP_FLUSH) /* flush / flush-n-inv both wait */ + wait_for_flush(); + + /* Switch back the DISCARD ONLY Invalidate mode */ + if (cacheop == OP_FLUSH_N_INV) + write_aux_reg(ARC_REG_DC_CTRL, tmp & ~DC_CTRL_INV_MODE_FLUSH); + + local_irq_restore(flags); +} + +#else + +#define __dc_entire_op(cacheop) +#define __dc_line_op(start, sz, cacheop) + +#endif /* CONFIG_ARC_HAS_DCACHE */ + + +#ifdef CONFIG_ARC_HAS_ICACHE + +/* + * I-Cache Aliasing in ARC700 VIPT caches + * + * For fetching code from I$, ARC700 uses vaddr (embedded in program code) + * to "index" into SET of cache-line and paddr from MMU to match the TAG + * in the WAYS of SET. + * + * However the CDU iterface (to flush/inv) lines from software, only takes + * paddr (to have simpler hardware interface). For simpler cases, using paddr + * alone suffices. + * e.g. 2-way-set-assoc, 16K I$ (8k MMU pg sz, 32b cache line size): + * way_sz = cache_sz / num_ways = 16k/2 = 8k + * num_sets = way_sz / line_sz = 8k/32 = 256 => 8 bits + * Ignoring the bottom 5 bits corresp to the off within a 32b cacheline, + * bits req for calc set-index = bits 12:5 (0 based). Since this range fits + * inside the bottom 13 bits of paddr, which are same for vaddr and paddr + * (with 8k pg sz), paddr alone can be safely used by CDU to unambigously + * locate a cache-line. + * + * However for a difft sized cache, say 32k I$, above math yields need + * for 14 bits of vaddr to locate a cache line, which can't be provided by + * paddr, since the bit 13 (0 based) might differ between the two. + * + * This lack of extra bits needed for correct line addressing, defines the + * classical problem of Cache aliasing with VIPT architectures + * num_aliases = 1 << extra_bits + * e.g. 2-way-set-assoc, 32K I$ with 8k MMU pg sz => 2 aliases + * 2-way-set-assoc, 64K I$ with 8k MMU pg sz => 4 aliases + * 2-way-set-assoc, 16K I$ with 8k MMU pg sz => NO aliases + * + * ------------------ + * 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-geom. + * 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. + * + * 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) + * + * Since vaddr was not available for all instances of I$ flush req by core + * kernel, the only safe way (non-optimal though) was to kill all possible + * lines which could represent an alias (even if they didnt represent one + * in execution). + * e.g. for 64K I$, 4 aliases possible, so we did + * flush start + * flush start | 0x01 + * flush start | 0x2 + * flush start | 0x3 + * + * The penalty was invoking the operation itself, since tag match is anyways + * paddr based, a line which didn't represent an alias would not match the + * paddr, hence wont be killed + * + * Note that aliasing concerns are independent of line-sz for a given cache + * geometry (size + set_assoc) because the extra bits required by line-sz are + * reduced from the set calc. + * e.g. 2-way-set-assoc, 32K I$ with 8k MMU pg sz and using math above + * 32b line-sz: 9 bits set-index-calc, 5 bits offset-in-line => 1 extra bit + * 64b line-sz: 8 bits set-index-calc, 6 bits offset-in-line => 1 extra bit + * + * ------------------ + * MMU v3 + * ------------------ + * This ver of MMU supports var page sizes (1k-16k) - Linux will 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 helpers for per line I-Cache invalidate. + * 3 routines to accpunt for 1, 2, 4 aliases possible + */ + +static void __ic_line_inv_no_alias(unsigned long start, int num_lines) +{ + while (num_lines-- > 0) { +#if (CONFIG_ARC_MMU_VER > 2) + write_aux_reg(ARC_REG_IC_PTAG, start); +#endif + write_aux_reg(ARC_REG_IC_IVIL, start); + start += ARC_ICACHE_LINE_LEN; + } +} + +static void __ic_line_inv_2_alias(unsigned long start, int num_lines) +{ + while (num_lines-- > 0) { + +#if (CONFIG_ARC_MMU_VER > 2) + /* + * MMU v3, CDU prog model (for line ops) now uses a new IC_PTAG + * reg to pass the "tag" bits and existing IVIL reg only looks + * at bits relevant for "index" (details above) + * Programming Notes: + * -when writing tag to PTAG reg, bit chopping can be avoided, + * CDU ignores non-tag bits. + * -Ideally "index" must be computed from vaddr, but it is not + * avail in these rtns. So to be safe, we kill the lines in all + * possible indexes corresp to num of aliases possible for + * given cache config. + */ + write_aux_reg(ARC_REG_IC_PTAG, start); + write_aux_reg(ARC_REG_IC_IVIL, + start & ~(0x1 << PAGE_SHIFT)); + write_aux_reg(ARC_REG_IC_IVIL, start | (0x1 << PAGE_SHIFT)); +#else + write_aux_reg(ARC_REG_IC_IVIL, start); + write_aux_reg(ARC_REG_IC_IVIL, start | 0x01); +#endif + start += ARC_ICACHE_LINE_LEN; + } +} + +static void __ic_line_inv_4_alias(unsigned long start, int num_lines) +{ + while (num_lines-- > 0) { + +#if (CONFIG_ARC_MMU_VER > 2) + write_aux_reg(ARC_REG_IC_PTAG, start); + + write_aux_reg(ARC_REG_IC_IVIL, + start & ~(0x3 << PAGE_SHIFT)); + write_aux_reg(ARC_REG_IC_IVIL, + start & ~(0x2 << PAGE_SHIFT)); + write_aux_reg(ARC_REG_IC_IVIL, + start & ~(0x1 << PAGE_SHIFT)); + write_aux_reg(ARC_REG_IC_IVIL, start | (0x3 << PAGE_SHIFT)); +#else + write_aux_reg(ARC_REG_IC_IVIL, start); + write_aux_reg(ARC_REG_IC_IVIL, start | 0x01); + write_aux_reg(ARC_REG_IC_IVIL, start | 0x02); + write_aux_reg(ARC_REG_IC_IVIL, start | 0x03); +#endif + start += ARC_ICACHE_LINE_LEN; + } +} + +static void __ic_line_inv(unsigned long start, unsigned long sz) +{ + unsigned long flags; + int num_lines, slack; + + /* + * Ensure we properly floor/ceil the non-line aligned/sized requests + * and have @start - aligned to cache line, and integral @num_lines + * However page sized flushes can be compile time optimised. + * -@start will be cache-line aligned already (being page aligned) + * -@sz will be integral multiple of line size (being page sized). + */ + if (!(__builtin_constant_p(sz) && sz == PAGE_SIZE)) { + slack = start & ~ICACHE_LINE_MASK; + sz += slack; + start -= slack; + } + + num_lines = DIV_ROUND_UP(sz, ARC_ICACHE_LINE_LEN); + + local_irq_save(flags); + (*___flush_icache_rtn) (start, num_lines); + local_irq_restore(flags); +} + +/* Unlike routines above, having vaddr for flush op (along with paddr), + * prevents the need to speculatively kill the lines in multiple sets + * based on ratio of way_sz : pg_sz + */ +static void __ic_line_inv_vaddr(unsigned long phy_start, + unsigned long vaddr, unsigned long sz) +{ + unsigned long flags; + int num_lines, slack; + unsigned int addr; + + slack = phy_start & ~ICACHE_LINE_MASK; + sz += slack; + phy_start -= slack; + num_lines = DIV_ROUND_UP(sz, ARC_ICACHE_LINE_LEN); + +#if (CONFIG_ARC_MMU_VER > 2) + vaddr &= ~ICACHE_LINE_MASK; + addr = phy_start; +#else + /* bits 17:13 of vaddr go as bits 4:0 of paddr */ + addr = phy_start | ((vaddr >> 13) & 0x1F); +#endif + + local_irq_save(flags); + while (num_lines-- > 0) { +#if (CONFIG_ARC_MMU_VER > 2) + /* tag comes from phy addr */ + write_aux_reg(ARC_REG_IC_PTAG, addr); + + /* index bits come from vaddr */ + write_aux_reg(ARC_REG_IC_IVIL, vaddr); + vaddr += ARC_ICACHE_LINE_LEN; +#else + /* this paddr contains vaddrs bits as needed */ + write_aux_reg(ARC_REG_IC_IVIL, addr); +#endif + addr += ARC_ICACHE_LINE_LEN; + } + local_irq_restore(flags); +} + +#else + +#define __ic_line_inv(start, sz) +#define __ic_line_inv_vaddr(pstart, vstart, sz) + +#endif /* CONFIG_ARC_HAS_ICACHE */ + + +/*********************************************************** + * Exported APIs + */ + +/* TBD: use pg_arch_1 to optimize this */ +void flush_dcache_page(struct page *page) +{ + __dc_line_op((unsigned long)page_address(page), PAGE_SIZE, OP_FLUSH); +} +EXPORT_SYMBOL(flush_dcache_page); + + +void dma_cache_wback_inv(unsigned long start, unsigned long sz) +{ + __dc_line_op(start, sz, OP_FLUSH_N_INV); +} +EXPORT_SYMBOL(dma_cache_wback_inv); + +void dma_cache_inv(unsigned long start, unsigned long sz) +{ + __dc_line_op(start, sz, OP_INV); +} +EXPORT_SYMBOL(dma_cache_inv); + +void dma_cache_wback(unsigned long start, unsigned long sz) +{ + __dc_line_op(start, sz, OP_FLUSH); +} +EXPORT_SYMBOL(dma_cache_wback); + +/* + * This is API for making I/D Caches consistent when modifying code + * (loadable modules, kprobes, etc) + * This is called on insmod, with kernel virtual address for CODE of + * the module. ARC cache maintenance ops require PHY address thus we + * need to convert vmalloc addr to PHY addr + */ +void flush_icache_range(unsigned long kstart, unsigned long kend) +{ + unsigned int tot_sz, off, sz; + unsigned long phy, pfn; + unsigned long flags; + + /* printk("Kernel Cache Cohenercy: %lx to %lx\n",kstart, kend); */ + + /* This is not the right API for user virtual address */ + if (kstart < TASK_SIZE) { + BUG_ON("Flush icache range for user virtual addr space"); + return; + } + + /* Shortcut for bigger flush ranges. + * Here we don't care if this was kernel virtual or phy addr + */ + tot_sz = kend - kstart; + if (tot_sz > PAGE_SIZE) { + flush_cache_all(); + return; + } + + /* Case: Kernel Phy addr (0x8000_0000 onwards) */ + if (likely(kstart > PAGE_OFFSET)) { + __ic_line_inv(kstart, kend - kstart); + __dc_line_op(kstart, kend - kstart, OP_FLUSH); + return; + } + + /* + * Case: Kernel Vaddr (0x7000_0000 to 0x7fff_ffff) + * (1) ARC Cache Maintenance ops only take Phy addr, hence special + * handling of kernel vaddr. + * + * (2) Despite @tot_sz being < PAGE_SIZE (bigger cases handled already), + * it still needs to handle a 2 page scenario, where the range + * straddles across 2 virtual pages and hence need for loop + */ + while (tot_sz > 0) { + off = kstart % PAGE_SIZE; + pfn = vmalloc_to_pfn((void *)kstart); + phy = (pfn << PAGE_SHIFT) + off; + sz = min_t(unsigned int, tot_sz, PAGE_SIZE - off); + local_irq_save(flags); + __dc_line_op(phy, sz, OP_FLUSH); + __ic_line_inv(phy, sz); + local_irq_restore(flags); + kstart += sz; + tot_sz -= sz; + } +} + +/* + * Optimised ver of flush_icache_range() with spec callers: ptrace/signals + * where vaddr is also available. This allows passing both vaddr and paddr + * bits to CDU for cache flush, short-circuting the current pessimistic algo + * which kills all possible aliases. + * An added adv of knowing that vaddr is user-vaddr avoids various checks + * and handling for k-vaddr, k-paddr as done in orig ver above + */ +void flush_icache_range_vaddr(unsigned long paddr, unsigned long u_vaddr, + int len) +{ + __ic_line_inv_vaddr(paddr, u_vaddr, len); + __dc_line_op(paddr, len, OP_FLUSH); +} + +/* + * XXX: This also needs to be optim using pg_arch_1 + * This is called when a page-cache page is about to be mapped into a + * user process' address space. It offers an opportunity for a + * port to ensure d-cache/i-cache coherency if necessary. + */ +void flush_icache_page(struct vm_area_struct *vma, struct page *page) +{ + if (!(vma->vm_flags & VM_EXEC)) + return; + + __ic_line_inv((unsigned long)page_address(page), PAGE_SIZE); +} + +void flush_icache_all(void) +{ + unsigned long flags; + + local_irq_save(flags); + + write_aux_reg(ARC_REG_IC_IVIC, 1); + + /* lr will not complete till the icache inv operation is not over */ + read_aux_reg(ARC_REG_IC_CTRL); + local_irq_restore(flags); +} + +noinline void flush_cache_all(void) +{ + unsigned long flags; + + local_irq_save(flags); + + flush_icache_all(); + __dc_entire_op(OP_FLUSH_N_INV); + + local_irq_restore(flags); + +} + +/********************************************************************** + * Explicit Cache flush request from user space via syscall + * Needed for JITs which generate code on the fly + */ +SYSCALL_DEFINE3(cacheflush, uint32_t, start, uint32_t, sz, uint32_t, flags) +{ + /* TBD: optimize this */ + flush_cache_all(); + return 0; +} |