Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
diff --git a/arch/sh64/mm/cache.c b/arch/sh64/mm/cache.c
new file mode 100644
index 0000000..3b87e25
--- /dev/null
+++ b/arch/sh64/mm/cache.c
@@ -0,0 +1,1041 @@
+/*
+ * 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.
+ *
+ * arch/sh64/mm/cache.c
+ *
+ * Original version Copyright (C) 2000, 2001 Paolo Alberelli
+ * Second version Copyright (C) benedict.gaster@superh.com 2002
+ * Third version Copyright Richard.Curnow@superh.com 2003
+ * Hacks to third version Copyright (C) 2003 Paul Mundt
+ */
+
+/****************************************************************************/
+
+#include <linux/config.h>
+#include <linux/init.h>
+#include <linux/mman.h>
+#include <linux/mm.h>
+#include <linux/threads.h>
+#include <asm/page.h>
+#include <asm/pgtable.h>
+#include <asm/processor.h>
+#include <asm/cache.h>
+#include <asm/tlb.h>
+#include <asm/io.h>
+#include <asm/uaccess.h>
+#include <asm/mmu_context.h>
+#include <asm/pgalloc.h> /* for flush_itlb_range */
+
+#include <linux/proc_fs.h>
+
+/* This function is in entry.S */
+extern unsigned long switch_and_save_asid(unsigned long new_asid);
+
+/* Wired TLB entry for the D-cache */
+static unsigned long long dtlb_cache_slot;
+
+/**
+ * sh64_cache_init()
+ *
+ * This is pretty much just a straightforward clone of the SH
+ * detect_cpu_and_cache_system().
+ *
+ * This function is responsible for setting up all of the cache
+ * info dynamically as well as taking care of CPU probing and
+ * setting up the relevant subtype data.
+ *
+ * FIXME: For the time being, we only really support the SH5-101
+ * out of the box, and don't support dynamic probing for things
+ * like the SH5-103 or even cut2 of the SH5-101. Implement this
+ * later!
+ */
+int __init sh64_cache_init(void)
+{
+ /*
+ * First, setup some sane values for the I-cache.
+ */
+ cpu_data->icache.ways = 4;
+ cpu_data->icache.sets = 256;
+ cpu_data->icache.linesz = L1_CACHE_BYTES;
+
+ /*
+ * FIXME: This can probably be cleaned up a bit as well.. for example,
+ * do we really need the way shift _and_ the way_step_shift ?? Judging
+ * by the existing code, I would guess no.. is there any valid reason
+ * why we need to be tracking this around?
+ */
+ cpu_data->icache.way_shift = 13;
+ cpu_data->icache.entry_shift = 5;
+ cpu_data->icache.set_shift = 4;
+ cpu_data->icache.way_step_shift = 16;
+ cpu_data->icache.asid_shift = 2;
+
+ /*
+ * way offset = cache size / associativity, so just don't factor in
+ * associativity in the first place..
+ */
+ cpu_data->icache.way_ofs = cpu_data->icache.sets *
+ cpu_data->icache.linesz;
+
+ cpu_data->icache.asid_mask = 0x3fc;
+ cpu_data->icache.idx_mask = 0x1fe0;
+ cpu_data->icache.epn_mask = 0xffffe000;
+ cpu_data->icache.flags = 0;
+
+ /*
+ * Next, setup some sane values for the D-cache.
+ *
+ * On the SH5, these are pretty consistent with the I-cache settings,
+ * so we just copy over the existing definitions.. these can be fixed
+ * up later, especially if we add runtime CPU probing.
+ *
+ * Though in the meantime it saves us from having to duplicate all of
+ * the above definitions..
+ */
+ cpu_data->dcache = cpu_data->icache;
+
+ /*
+ * Setup any cache-related flags here
+ */
+#if defined(CONFIG_DCACHE_WRITE_THROUGH)
+ set_bit(SH_CACHE_MODE_WT, &(cpu_data->dcache.flags));
+#elif defined(CONFIG_DCACHE_WRITE_BACK)
+ set_bit(SH_CACHE_MODE_WB, &(cpu_data->dcache.flags));
+#endif
+
+ /*
+ * We also need to reserve a slot for the D-cache in the DTLB, so we
+ * do this now ..
+ */
+ dtlb_cache_slot = sh64_get_wired_dtlb_entry();
+
+ return 0;
+}
+
+#ifdef CONFIG_DCACHE_DISABLED
+#define sh64_dcache_purge_all() do { } while (0)
+#define sh64_dcache_purge_coloured_phy_page(paddr, eaddr) do { } while (0)
+#define sh64_dcache_purge_user_range(mm, start, end) do { } while (0)
+#define sh64_dcache_purge_phy_page(paddr) do { } while (0)
+#define sh64_dcache_purge_virt_page(mm, eaddr) do { } while (0)
+#define sh64_dcache_purge_kernel_range(start, end) do { } while (0)
+#define sh64_dcache_wback_current_user_range(start, end) do { } while (0)
+#endif
+
+/*##########################################################################*/
+
+/* From here onwards, a rewrite of the implementation,
+ by Richard.Curnow@superh.com.
+
+ The major changes in this compared to the old version are;
+ 1. use more selective purging through OCBP instead of using ALLOCO to purge
+ by natural replacement. This avoids purging out unrelated cache lines
+ that happen to be in the same set.
+ 2. exploit the APIs copy_user_page and clear_user_page better
+ 3. be more selective about I-cache purging, in particular use invalidate_all
+ more sparingly.
+
+ */
+
+/*##########################################################################
+ SUPPORT FUNCTIONS
+ ##########################################################################*/
+
+/****************************************************************************/
+/* The following group of functions deal with mapping and unmapping a temporary
+ page into the DTLB slot that have been set aside for our exclusive use. */
+/* In order to accomplish this, we use the generic interface for adding and
+ removing a wired slot entry as defined in arch/sh64/mm/tlb.c */
+/****************************************************************************/
+
+static unsigned long slot_own_flags;
+
+static inline void sh64_setup_dtlb_cache_slot(unsigned long eaddr, unsigned long asid, unsigned long paddr)
+{
+ local_irq_save(slot_own_flags);
+ sh64_setup_tlb_slot(dtlb_cache_slot, eaddr, asid, paddr);
+}
+
+static inline void sh64_teardown_dtlb_cache_slot(void)
+{
+ sh64_teardown_tlb_slot(dtlb_cache_slot);
+ local_irq_restore(slot_own_flags);
+}
+
+/****************************************************************************/
+
+#ifndef CONFIG_ICACHE_DISABLED
+
+static void __inline__ sh64_icache_inv_all(void)
+{
+ unsigned long long addr, flag, data;
+ unsigned int flags;
+
+ addr=ICCR0;
+ flag=ICCR0_ICI;
+ data=0;
+
+ /* Make this a critical section for safety (probably not strictly necessary.) */
+ local_irq_save(flags);
+
+ /* Without %1 it gets unexplicably wrong */
+ asm volatile("getcfg %3, 0, %0\n\t"
+ "or %0, %2, %0\n\t"
+ "putcfg %3, 0, %0\n\t"
+ "synci"
+ : "=&r" (data)
+ : "0" (data), "r" (flag), "r" (addr));
+
+ local_irq_restore(flags);
+}
+
+static void sh64_icache_inv_kernel_range(unsigned long start, unsigned long end)
+{
+ /* Invalidate range of addresses [start,end] from the I-cache, where
+ * the addresses lie in the kernel superpage. */
+
+ unsigned long long ullend, addr, aligned_start;
+#if (NEFF == 32)
+ aligned_start = (unsigned long long)(signed long long)(signed long) start;
+#else
+#error "NEFF != 32"
+#endif
+ aligned_start &= L1_CACHE_ALIGN_MASK;
+ addr = aligned_start;
+#if (NEFF == 32)
+ ullend = (unsigned long long) (signed long long) (signed long) end;
+#else
+#error "NEFF != 32"
+#endif
+ while (addr <= ullend) {
+ asm __volatile__ ("icbi %0, 0" : : "r" (addr));
+ addr += L1_CACHE_BYTES;
+ }
+}
+
+static void sh64_icache_inv_user_page(struct vm_area_struct *vma, unsigned long eaddr)
+{
+ /* If we get called, we know that vma->vm_flags contains VM_EXEC.
+ Also, eaddr is page-aligned. */
+
+ unsigned long long addr, end_addr;
+ unsigned long flags = 0;
+ unsigned long running_asid, vma_asid;
+ addr = eaddr;
+ end_addr = addr + PAGE_SIZE;
+
+ /* Check whether we can use the current ASID for the I-cache
+ invalidation. For example, if we're called via
+ access_process_vm->flush_cache_page->here, (e.g. when reading from
+ /proc), 'running_asid' will be that of the reader, not of the
+ victim.
+
+ Also, note the risk that we might get pre-empted between the ASID
+ compare and blocking IRQs, and before we regain control, the
+ pid->ASID mapping changes. However, the whole cache will get
+ invalidated when the mapping is renewed, so the worst that can
+ happen is that the loop below ends up invalidating somebody else's
+ cache entries.
+ */
+
+ running_asid = get_asid();
+ vma_asid = (vma->vm_mm->context & MMU_CONTEXT_ASID_MASK);
+ if (running_asid != vma_asid) {
+ local_irq_save(flags);
+ switch_and_save_asid(vma_asid);
+ }
+ while (addr < end_addr) {
+ /* Worth unrolling a little */
+ asm __volatile__("icbi %0, 0" : : "r" (addr));
+ asm __volatile__("icbi %0, 32" : : "r" (addr));
+ asm __volatile__("icbi %0, 64" : : "r" (addr));
+ asm __volatile__("icbi %0, 96" : : "r" (addr));
+ addr += 128;
+ }
+ if (running_asid != vma_asid) {
+ switch_and_save_asid(running_asid);
+ local_irq_restore(flags);
+ }
+}
+
+/****************************************************************************/
+
+static void sh64_icache_inv_user_page_range(struct mm_struct *mm,
+ unsigned long start, unsigned long end)
+{
+ /* Used for invalidating big chunks of I-cache, i.e. assume the range
+ is whole pages. If 'start' or 'end' is not page aligned, the code
+ is conservative and invalidates to the ends of the enclosing pages.
+ This is functionally OK, just a performance loss. */
+
+ /* See the comments below in sh64_dcache_purge_user_range() regarding
+ the choice of algorithm. However, for the I-cache option (2) isn't
+ available because there are no physical tags so aliases can't be
+ resolved. The icbi instruction has to be used through the user
+ mapping. Because icbi is cheaper than ocbp on a cache hit, it
+ would be cheaper to use the selective code for a large range than is
+ possible with the D-cache. Just assume 64 for now as a working
+ figure.
+ */
+
+ int n_pages;
+
+ if (!mm) return;
+
+ n_pages = ((end - start) >> PAGE_SHIFT);
+ if (n_pages >= 64) {
+ sh64_icache_inv_all();
+ } else {
+ unsigned long aligned_start;
+ unsigned long eaddr;
+ unsigned long after_last_page_start;
+ unsigned long mm_asid, current_asid;
+ unsigned long long flags = 0ULL;
+
+ mm_asid = mm->context & MMU_CONTEXT_ASID_MASK;
+ current_asid = get_asid();
+
+ if (mm_asid != current_asid) {
+ /* Switch ASID and run the invalidate loop under cli */
+ local_irq_save(flags);
+ switch_and_save_asid(mm_asid);
+ }
+
+ aligned_start = start & PAGE_MASK;
+ after_last_page_start = PAGE_SIZE + ((end - 1) & PAGE_MASK);
+
+ while (aligned_start < after_last_page_start) {
+ struct vm_area_struct *vma;
+ unsigned long vma_end;
+ vma = find_vma(mm, aligned_start);
+ if (!vma || (aligned_start <= vma->vm_end)) {
+ /* Avoid getting stuck in an error condition */
+ aligned_start += PAGE_SIZE;
+ continue;
+ }
+ vma_end = vma->vm_end;
+ if (vma->vm_flags & VM_EXEC) {
+ /* Executable */
+ eaddr = aligned_start;
+ while (eaddr < vma_end) {
+ sh64_icache_inv_user_page(vma, eaddr);
+ eaddr += PAGE_SIZE;
+ }
+ }
+ aligned_start = vma->vm_end; /* Skip to start of next region */
+ }
+ if (mm_asid != current_asid) {
+ switch_and_save_asid(current_asid);
+ local_irq_restore(flags);
+ }
+ }
+}
+
+static void sh64_icache_inv_user_small_range(struct mm_struct *mm,
+ unsigned long start, int len)
+{
+
+ /* Invalidate a small range of user context I-cache, not necessarily
+ page (or even cache-line) aligned. */
+
+ unsigned long long eaddr = start;
+ unsigned long long eaddr_end = start + len;
+ unsigned long current_asid, mm_asid;
+ unsigned long long flags;
+ unsigned long long epage_start;
+
+ /* Since this is used inside ptrace, the ASID in the mm context
+ typically won't match current_asid. We'll have to switch ASID to do
+ this. For safety, and given that the range will be small, do all
+ this under cli.
+
+ Note, there is a hazard that the ASID in mm->context is no longer
+ actually associated with mm, i.e. if the mm->context has started a
+ new cycle since mm was last active. However, this is just a
+ performance issue: all that happens is that we invalidate lines
+ belonging to another mm, so the owning process has to refill them
+ when that mm goes live again. mm itself can't have any cache
+ entries because there will have been a flush_cache_all when the new
+ mm->context cycle started. */
+
+ /* Align to start of cache line. Otherwise, suppose len==8 and start
+ was at 32N+28 : the last 4 bytes wouldn't get invalidated. */
+ eaddr = start & L1_CACHE_ALIGN_MASK;
+ eaddr_end = start + len;
+
+ local_irq_save(flags);
+ mm_asid = mm->context & MMU_CONTEXT_ASID_MASK;
+ current_asid = switch_and_save_asid(mm_asid);
+
+ epage_start = eaddr & PAGE_MASK;
+
+ while (eaddr < eaddr_end)
+ {
+ asm __volatile__("icbi %0, 0" : : "r" (eaddr));
+ eaddr += L1_CACHE_BYTES;
+ }
+ switch_and_save_asid(current_asid);
+ local_irq_restore(flags);
+}
+
+static void sh64_icache_inv_current_user_range(unsigned long start, unsigned long end)
+{
+ /* The icbi instruction never raises ITLBMISS. i.e. if there's not a
+ cache hit on the virtual tag the instruction ends there, without a
+ TLB lookup. */
+
+ unsigned long long aligned_start;
+ unsigned long long ull_end;
+ unsigned long long addr;
+
+ ull_end = end;
+
+ /* Just invalidate over the range using the natural addresses. TLB
+ miss handling will be OK (TBC). Since it's for the current process,
+ either we're already in the right ASID context, or the ASIDs have
+ been recycled since we were last active in which case we might just
+ invalidate another processes I-cache entries : no worries, just a
+ performance drop for him. */
+ aligned_start = start & L1_CACHE_ALIGN_MASK;
+ addr = aligned_start;
+ while (addr < ull_end) {
+ asm __volatile__ ("icbi %0, 0" : : "r" (addr));
+ asm __volatile__ ("nop");
+ asm __volatile__ ("nop");
+ addr += L1_CACHE_BYTES;
+ }
+}
+
+#endif /* !CONFIG_ICACHE_DISABLED */
+
+/****************************************************************************/
+
+#ifndef CONFIG_DCACHE_DISABLED
+
+/* Buffer used as the target of alloco instructions to purge data from cache
+ sets by natural eviction. -- RPC */
+#define DUMMY_ALLOCO_AREA_SIZE L1_CACHE_SIZE_BYTES + (1024 * 4)
+static unsigned char dummy_alloco_area[DUMMY_ALLOCO_AREA_SIZE] __cacheline_aligned = { 0, };
+
+/****************************************************************************/
+
+static void __inline__ sh64_dcache_purge_sets(int sets_to_purge_base, int n_sets)
+{
+ /* Purge all ways in a particular block of sets, specified by the base
+ set number and number of sets. Can handle wrap-around, if that's
+ needed. */
+
+ int dummy_buffer_base_set;
+ unsigned long long eaddr, eaddr0, eaddr1;
+ int j;
+ int set_offset;
+
+ dummy_buffer_base_set = ((int)&dummy_alloco_area & cpu_data->dcache.idx_mask) >> cpu_data->dcache.entry_shift;
+ set_offset = sets_to_purge_base - dummy_buffer_base_set;
+
+ for (j=0; j<n_sets; j++, set_offset++) {
+ set_offset &= (cpu_data->dcache.sets - 1);
+ eaddr0 = (unsigned long long)dummy_alloco_area + (set_offset << cpu_data->dcache.entry_shift);
+
+ /* Do one alloco which hits the required set per cache way. For
+ write-back mode, this will purge the #ways resident lines. There's
+ little point unrolling this loop because the allocos stall more if
+ they're too close together. */
+ eaddr1 = eaddr0 + cpu_data->dcache.way_ofs * cpu_data->dcache.ways;
+ for (eaddr=eaddr0; eaddr<eaddr1; eaddr+=cpu_data->dcache.way_ofs) {
+ asm __volatile__ ("alloco %0, 0" : : "r" (eaddr));
+ asm __volatile__ ("synco"); /* TAKum03020 */
+ }
+
+ eaddr1 = eaddr0 + cpu_data->dcache.way_ofs * cpu_data->dcache.ways;
+ for (eaddr=eaddr0; eaddr<eaddr1; eaddr+=cpu_data->dcache.way_ofs) {
+ /* Load from each address. Required because alloco is a NOP if
+ the cache is write-through. Write-through is a config option. */
+ if (test_bit(SH_CACHE_MODE_WT, &(cpu_data->dcache.flags)))
+ *(volatile unsigned char *)(int)eaddr;
+ }
+ }
+
+ /* Don't use OCBI to invalidate the lines. That costs cycles directly.
+ If the dummy block is just left resident, it will naturally get
+ evicted as required. */
+
+ return;
+}
+
+/****************************************************************************/
+
+static void sh64_dcache_purge_all(void)
+{
+ /* Purge the entire contents of the dcache. The most efficient way to
+ achieve this is to use alloco instructions on a region of unused
+ memory equal in size to the cache, thereby causing the current
+ contents to be discarded by natural eviction. The alternative,
+ namely reading every tag, setting up a mapping for the corresponding
+ page and doing an OCBP for the line, would be much more expensive.
+ */
+
+ sh64_dcache_purge_sets(0, cpu_data->dcache.sets);
+
+ return;
+
+}
+
+/****************************************************************************/
+
+static void sh64_dcache_purge_kernel_range(unsigned long start, unsigned long end)
+{
+ /* Purge the range of addresses [start,end] from the D-cache. The
+ addresses lie in the superpage mapping. There's no harm if we
+ overpurge at either end - just a small performance loss. */
+ unsigned long long ullend, addr, aligned_start;
+#if (NEFF == 32)
+ aligned_start = (unsigned long long)(signed long long)(signed long) start;
+#else
+#error "NEFF != 32"
+#endif
+ aligned_start &= L1_CACHE_ALIGN_MASK;
+ addr = aligned_start;
+#if (NEFF == 32)
+ ullend = (unsigned long long) (signed long long) (signed long) end;
+#else
+#error "NEFF != 32"
+#endif
+ while (addr <= ullend) {
+ asm __volatile__ ("ocbp %0, 0" : : "r" (addr));
+ addr += L1_CACHE_BYTES;
+ }
+ return;
+}
+
+/* Assumes this address (+ (2**n_synbits) pages up from it) aren't used for
+ anything else in the kernel */
+#define MAGIC_PAGE0_START 0xffffffffec000000ULL
+
+static void sh64_dcache_purge_coloured_phy_page(unsigned long paddr, unsigned long eaddr)
+{
+ /* Purge the physical page 'paddr' from the cache. It's known that any
+ cache lines requiring attention have the same page colour as the the
+ address 'eaddr'.
+
+ This relies on the fact that the D-cache matches on physical tags
+ when no virtual tag matches. So we create an alias for the original
+ page and purge through that. (Alternatively, we could have done
+ this by switching ASID to match the original mapping and purged
+ through that, but that involves ASID switching cost + probably a
+ TLBMISS + refill anyway.)
+ */
+
+ unsigned long long magic_page_start;
+ unsigned long long magic_eaddr, magic_eaddr_end;
+
+ magic_page_start = MAGIC_PAGE0_START + (eaddr & CACHE_OC_SYN_MASK);
+
+ /* As long as the kernel is not pre-emptible, this doesn't need to be
+ under cli/sti. */
+
+ sh64_setup_dtlb_cache_slot(magic_page_start, get_asid(), paddr);
+
+ magic_eaddr = magic_page_start;
+ magic_eaddr_end = magic_eaddr + PAGE_SIZE;
+ while (magic_eaddr < magic_eaddr_end) {
+ /* Little point in unrolling this loop - the OCBPs are blocking
+ and won't go any quicker (i.e. the loop overhead is parallel
+ to part of the OCBP execution.) */
+ asm __volatile__ ("ocbp %0, 0" : : "r" (magic_eaddr));
+ magic_eaddr += L1_CACHE_BYTES;
+ }
+
+ sh64_teardown_dtlb_cache_slot();
+}
+
+/****************************************************************************/
+
+static void sh64_dcache_purge_phy_page(unsigned long paddr)
+{
+ /* Pure a page given its physical start address, by creating a
+ temporary 1 page mapping and purging across that. Even if we know
+ the virtual address (& vma or mm) of the page, the method here is
+ more elegant because it avoids issues of coping with page faults on
+ the purge instructions (i.e. no special-case code required in the
+ critical path in the TLB miss handling). */
+
+ unsigned long long eaddr_start, eaddr, eaddr_end;
+ int i;
+
+ /* As long as the kernel is not pre-emptible, this doesn't need to be
+ under cli/sti. */
+
+ eaddr_start = MAGIC_PAGE0_START;
+ for (i=0; i < (1 << CACHE_OC_N_SYNBITS); i++) {
+ sh64_setup_dtlb_cache_slot(eaddr_start, get_asid(), paddr);
+
+ eaddr = eaddr_start;
+ eaddr_end = eaddr + PAGE_SIZE;
+ while (eaddr < eaddr_end) {
+ asm __volatile__ ("ocbp %0, 0" : : "r" (eaddr));
+ eaddr += L1_CACHE_BYTES;
+ }
+
+ sh64_teardown_dtlb_cache_slot();
+ eaddr_start += PAGE_SIZE;
+ }
+}
+
+static void sh64_dcache_purge_user_page(struct mm_struct *mm, unsigned long eaddr)
+{
+ pgd_t *pgd;
+ pmd_t *pmd;
+ pte_t *pte;
+ pte_t entry;
+ unsigned long paddr;
+
+ /* NOTE : all the callers of this have mm->page_table_lock held, so the
+ following page table traversal is safe even on SMP/pre-emptible. */
+
+ if (!mm) return; /* No way to find physical address of page */
+ pgd = pgd_offset(mm, eaddr);
+ if (pgd_bad(*pgd)) return;
+
+ pmd = pmd_offset(pgd, eaddr);
+ if (pmd_none(*pmd) || pmd_bad(*pmd)) return;
+
+ pte = pte_offset_kernel(pmd, eaddr);
+ entry = *pte;
+ if (pte_none(entry) || !pte_present(entry)) return;
+
+ paddr = pte_val(entry) & PAGE_MASK;
+
+ sh64_dcache_purge_coloured_phy_page(paddr, eaddr);
+
+}
+/****************************************************************************/
+
+static void sh64_dcache_purge_user_range(struct mm_struct *mm,
+ unsigned long start, unsigned long end)
+{
+ /* There are at least 5 choices for the implementation of this, with
+ pros (+), cons(-), comments(*):
+
+ 1. ocbp each line in the range through the original user's ASID
+ + no lines spuriously evicted
+ - tlbmiss handling (must either handle faults on demand => extra
+ special-case code in tlbmiss critical path), or map the page in
+ advance (=> flush_tlb_range in advance to avoid multiple hits)
+ - ASID switching
+ - expensive for large ranges
+
+ 2. temporarily map each page in the range to a special effective
+ address and ocbp through the temporary mapping; relies on the
+ fact that SH-5 OCB* always do TLB lookup and match on ptags (they
+ never look at the etags)
+ + no spurious evictions
+ - expensive for large ranges
+ * surely cheaper than (1)
+
+ 3. walk all the lines in the cache, check the tags, if a match
+ occurs create a page mapping to ocbp the line through
+ + no spurious evictions
+ - tag inspection overhead
+ - (especially for small ranges)
+ - potential cost of setting up/tearing down page mapping for
+ every line that matches the range
+ * cost partly independent of range size
+
+ 4. walk all the lines in the cache, check the tags, if a match
+ occurs use 4 * alloco to purge the line (+3 other probably
+ innocent victims) by natural eviction
+ + no tlb mapping overheads
+ - spurious evictions
+ - tag inspection overhead
+
+ 5. implement like flush_cache_all
+ + no tag inspection overhead
+ - spurious evictions
+ - bad for small ranges
+
+ (1) can be ruled out as more expensive than (2). (2) appears best
+ for small ranges. The choice between (3), (4) and (5) for large
+ ranges and the range size for the large/small boundary need
+ benchmarking to determine.
+
+ For now use approach (2) for small ranges and (5) for large ones.
+
+ */
+
+ int n_pages;
+
+ n_pages = ((end - start) >> PAGE_SHIFT);
+ if (n_pages >= 64) {
+#if 1
+ sh64_dcache_purge_all();
+#else
+ unsigned long long set, way;
+ unsigned long mm_asid = mm->context & MMU_CONTEXT_ASID_MASK;
+ for (set = 0; set < cpu_data->dcache.sets; set++) {
+ unsigned long long set_base_config_addr = CACHE_OC_ADDRESS_ARRAY + (set << cpu_data->dcache.set_shift);
+ for (way = 0; way < cpu_data->dcache.ways; way++) {
+ unsigned long long config_addr = set_base_config_addr + (way << cpu_data->dcache.way_step_shift);
+ unsigned long long tag0;
+ unsigned long line_valid;
+
+ asm __volatile__("getcfg %1, 0, %0" : "=r" (tag0) : "r" (config_addr));
+ line_valid = tag0 & SH_CACHE_VALID;
+ if (line_valid) {
+ unsigned long cache_asid;
+ unsigned long epn;
+
+ cache_asid = (tag0 & cpu_data->dcache.asid_mask) >> cpu_data->dcache.asid_shift;
+ /* The next line needs some
+ explanation. The virtual tags
+ encode bits [31:13] of the virtual
+ address, bit [12] of the 'tag' being
+ implied by the cache set index. */
+ epn = (tag0 & cpu_data->dcache.epn_mask) | ((set & 0x80) << cpu_data->dcache.entry_shift);
+
+ if ((cache_asid == mm_asid) && (start <= epn) && (epn < end)) {
+ /* TODO : could optimise this
+ call by batching multiple
+ adjacent sets together. */
+ sh64_dcache_purge_sets(set, 1);
+ break; /* Don't waste time inspecting other ways for this set */
+ }
+ }
+ }
+ }
+#endif
+ } else {
+ /* 'Small' range */
+ unsigned long aligned_start;
+ unsigned long eaddr;
+ unsigned long last_page_start;
+
+ aligned_start = start & PAGE_MASK;
+ /* 'end' is 1 byte beyond the end of the range */
+ last_page_start = (end - 1) & PAGE_MASK;
+
+ eaddr = aligned_start;
+ while (eaddr <= last_page_start) {
+ sh64_dcache_purge_user_page(mm, eaddr);
+ eaddr += PAGE_SIZE;
+ }
+ }
+ return;
+}
+
+static void sh64_dcache_wback_current_user_range(unsigned long start, unsigned long end)
+{
+ unsigned long long aligned_start;
+ unsigned long long ull_end;
+ unsigned long long addr;
+
+ ull_end = end;
+
+ /* Just wback over the range using the natural addresses. TLB miss
+ handling will be OK (TBC) : the range has just been written to by
+ the signal frame setup code, so the PTEs must exist.
+
+ Note, if we have CONFIG_PREEMPT and get preempted inside this loop,
+ it doesn't matter, even if the pid->ASID mapping changes whilst
+ we're away. In that case the cache will have been flushed when the
+ mapping was renewed. So the writebacks below will be nugatory (and
+ we'll doubtless have to fault the TLB entry/ies in again with the
+ new ASID), but it's a rare case.
+ */
+ aligned_start = start & L1_CACHE_ALIGN_MASK;
+ addr = aligned_start;
+ while (addr < ull_end) {
+ asm __volatile__ ("ocbwb %0, 0" : : "r" (addr));
+ addr += L1_CACHE_BYTES;
+ }
+}
+
+/****************************************************************************/
+
+/* These *MUST* lie in an area of virtual address space that's otherwise unused. */
+#define UNIQUE_EADDR_START 0xe0000000UL
+#define UNIQUE_EADDR_END 0xe8000000UL
+
+static unsigned long sh64_make_unique_eaddr(unsigned long user_eaddr, unsigned long paddr)
+{
+ /* Given a physical address paddr, and a user virtual address
+ user_eaddr which will eventually be mapped to it, create a one-off
+ kernel-private eaddr mapped to the same paddr. This is used for
+ creating special destination pages for copy_user_page and
+ clear_user_page */
+
+ static unsigned long current_pointer = UNIQUE_EADDR_START;
+ unsigned long coloured_pointer;
+
+ if (current_pointer == UNIQUE_EADDR_END) {
+ sh64_dcache_purge_all();
+ current_pointer = UNIQUE_EADDR_START;
+ }
+
+ coloured_pointer = (current_pointer & ~CACHE_OC_SYN_MASK) | (user_eaddr & CACHE_OC_SYN_MASK);
+ sh64_setup_dtlb_cache_slot(coloured_pointer, get_asid(), paddr);
+
+ current_pointer += (PAGE_SIZE << CACHE_OC_N_SYNBITS);
+
+ return coloured_pointer;
+}
+
+/****************************************************************************/
+
+static void sh64_copy_user_page_coloured(void *to, void *from, unsigned long address)
+{
+ void *coloured_to;
+
+ /* Discard any existing cache entries of the wrong colour. These are
+ present quite often, if the kernel has recently used the page
+ internally, then given it up, then it's been allocated to the user.
+ */
+ sh64_dcache_purge_coloured_phy_page(__pa(to), (unsigned long) to);
+
+ coloured_to = (void *) sh64_make_unique_eaddr(address, __pa(to));
+ sh64_page_copy(from, coloured_to);
+
+ sh64_teardown_dtlb_cache_slot();
+}
+
+static void sh64_clear_user_page_coloured(void *to, unsigned long address)
+{
+ void *coloured_to;
+
+ /* Discard any existing kernel-originated lines of the wrong colour (as
+ above) */
+ sh64_dcache_purge_coloured_phy_page(__pa(to), (unsigned long) to);
+
+ coloured_to = (void *) sh64_make_unique_eaddr(address, __pa(to));
+ sh64_page_clear(coloured_to);
+
+ sh64_teardown_dtlb_cache_slot();
+}
+
+#endif /* !CONFIG_DCACHE_DISABLED */
+
+/****************************************************************************/
+
+/*##########################################################################
+ EXTERNALLY CALLABLE API.
+ ##########################################################################*/
+
+/* These functions are described in Documentation/cachetlb.txt.
+ Each one of these functions varies in behaviour depending on whether the
+ I-cache and/or D-cache are configured out.
+
+ Note that the Linux term 'flush' corresponds to what is termed 'purge' in
+ the sh/sh64 jargon for the D-cache, i.e. write back dirty data then
+ invalidate the cache lines, and 'invalidate' for the I-cache.
+ */
+
+#undef FLUSH_TRACE
+
+void flush_cache_all(void)
+{
+ /* Invalidate the entire contents of both caches, after writing back to
+ memory any dirty data from the D-cache. */
+ sh64_dcache_purge_all();
+ sh64_icache_inv_all();
+}
+
+/****************************************************************************/
+
+void flush_cache_mm(struct mm_struct *mm)
+{
+ /* Invalidate an entire user-address space from both caches, after
+ writing back dirty data (e.g. for shared mmap etc). */
+
+ /* This could be coded selectively by inspecting all the tags then
+ doing 4*alloco on any set containing a match (as for
+ flush_cache_range), but fork/exit/execve (where this is called from)
+ are expensive anyway. */
+
+ /* Have to do a purge here, despite the comments re I-cache below.
+ There could be odd-coloured dirty data associated with the mm still
+ in the cache - if this gets written out through natural eviction
+ after the kernel has reused the page there will be chaos.
+ */
+
+ sh64_dcache_purge_all();
+
+ /* The mm being torn down won't ever be active again, so any Icache
+ lines tagged with its ASID won't be visible for the rest of the
+ lifetime of this ASID cycle. Before the ASID gets reused, there
+ will be a flush_cache_all. Hence we don't need to touch the
+ I-cache. This is similar to the lack of action needed in
+ flush_tlb_mm - see fault.c. */
+}
+
+/****************************************************************************/
+
+void flush_cache_range(struct vm_area_struct *vma, unsigned long start,
+ unsigned long end)
+{
+ struct mm_struct *mm = vma->vm_mm;
+
+ /* Invalidate (from both caches) the range [start,end) of virtual
+ addresses from the user address space specified by mm, after writing
+ back any dirty data.
+
+ Note(1), 'end' is 1 byte beyond the end of the range to flush.
+
+ Note(2), this is called with mm->page_table_lock held.*/
+
+ sh64_dcache_purge_user_range(mm, start, end);
+ sh64_icache_inv_user_page_range(mm, start, end);
+}
+
+/****************************************************************************/
+
+void flush_cache_page(struct vm_area_struct *vma, unsigned long eaddr, unsigned long pfn)
+{
+ /* Invalidate any entries in either cache for the vma within the user
+ address space vma->vm_mm for the page starting at virtual address
+ 'eaddr'. This seems to be used primarily in breaking COW. Note,
+ the I-cache must be searched too in case the page in question is
+ both writable and being executed from (e.g. stack trampolines.)
+
+ Note(1), this is called with mm->page_table_lock held.
+ */
+
+ sh64_dcache_purge_phy_page(pfn << PAGE_SHIFT);
+
+ if (vma->vm_flags & VM_EXEC) {
+ sh64_icache_inv_user_page(vma, eaddr);
+ }
+}
+
+/****************************************************************************/
+
+#ifndef CONFIG_DCACHE_DISABLED
+
+void copy_user_page(void *to, void *from, unsigned long address, struct page *page)
+{
+ /* 'from' and 'to' are kernel virtual addresses (within the superpage
+ mapping of the physical RAM). 'address' is the user virtual address
+ where the copy 'to' will be mapped after. This allows a custom
+ mapping to be used to ensure that the new copy is placed in the
+ right cache sets for the user to see it without having to bounce it
+ out via memory. Note however : the call to flush_page_to_ram in
+ (generic)/mm/memory.c:(break_cow) undoes all this good work in that one
+ very important case!
+
+ TBD : can we guarantee that on every call, any cache entries for
+ 'from' are in the same colour sets as 'address' also? i.e. is this
+ always used just to deal with COW? (I suspect not). */
+
+ /* There are two possibilities here for when the page 'from' was last accessed:
+ * by the kernel : this is OK, no purge required.
+ * by the/a user (e.g. for break_COW) : need to purge.
+
+ If the potential user mapping at 'address' is the same colour as
+ 'from' there is no need to purge any cache lines from the 'from'
+ page mapped into cache sets of colour 'address'. (The copy will be
+ accessing the page through 'from').
+ */
+
+ if (((address ^ (unsigned long) from) & CACHE_OC_SYN_MASK) != 0) {
+ sh64_dcache_purge_coloured_phy_page(__pa(from), address);
+ }
+
+ if (((address ^ (unsigned long) to) & CACHE_OC_SYN_MASK) == 0) {
+ /* No synonym problem on destination */
+ sh64_page_copy(from, to);
+ } else {
+ sh64_copy_user_page_coloured(to, from, address);
+ }
+
+ /* Note, don't need to flush 'from' page from the cache again - it's
+ done anyway by the generic code */
+}
+
+void clear_user_page(void *to, unsigned long address, struct page *page)
+{
+ /* 'to' is a kernel virtual address (within the superpage
+ mapping of the physical RAM). 'address' is the user virtual address
+ where the 'to' page will be mapped after. This allows a custom
+ mapping to be used to ensure that the new copy is placed in the
+ right cache sets for the user to see it without having to bounce it
+ out via memory.
+ */
+
+ if (((address ^ (unsigned long) to) & CACHE_OC_SYN_MASK) == 0) {
+ /* No synonym problem on destination */
+ sh64_page_clear(to);
+ } else {
+ sh64_clear_user_page_coloured(to, address);
+ }
+}
+
+#endif /* !CONFIG_DCACHE_DISABLED */
+
+/****************************************************************************/
+
+void flush_dcache_page(struct page *page)
+{
+ sh64_dcache_purge_phy_page(page_to_phys(page));
+ wmb();
+}
+
+/****************************************************************************/
+
+void flush_icache_range(unsigned long start, unsigned long end)
+{
+ /* Flush the range [start,end] of kernel virtual adddress space from
+ the I-cache. The corresponding range must be purged from the
+ D-cache also because the SH-5 doesn't have cache snooping between
+ the caches. The addresses will be visible through the superpage
+ mapping, therefore it's guaranteed that there no cache entries for
+ the range in cache sets of the wrong colour.
+
+ Primarily used for cohering the I-cache after a module has
+ been loaded. */
+
+ /* We also make sure to purge the same range from the D-cache since
+ flush_page_to_ram() won't be doing this for us! */
+
+ sh64_dcache_purge_kernel_range(start, end);
+ wmb();
+ sh64_icache_inv_kernel_range(start, end);
+}
+
+/****************************************************************************/
+
+void flush_icache_user_range(struct vm_area_struct *vma,
+ struct page *page, unsigned long addr, int len)
+{
+ /* Flush the range of user (defined by vma->vm_mm) address space
+ starting at 'addr' for 'len' bytes from the cache. The range does
+ not straddle a page boundary, the unique physical page containing
+ the range is 'page'. This seems to be used mainly for invalidating
+ an address range following a poke into the program text through the
+ ptrace() call from another process (e.g. for BRK instruction
+ insertion). */
+
+ sh64_dcache_purge_coloured_phy_page(page_to_phys(page), addr);
+ mb();
+
+ if (vma->vm_flags & VM_EXEC) {
+ sh64_icache_inv_user_small_range(vma->vm_mm, addr, len);
+ }
+}
+
+/*##########################################################################
+ ARCH/SH64 PRIVATE CALLABLE API.
+ ##########################################################################*/
+
+void flush_cache_sigtramp(unsigned long start, unsigned long end)
+{
+ /* For the address range [start,end), write back the data from the
+ D-cache and invalidate the corresponding region of the I-cache for
+ the current process. Used to flush signal trampolines on the stack
+ to make them executable. */
+
+ sh64_dcache_wback_current_user_range(start, end);
+ wmb();
+ sh64_icache_inv_current_user_range(start, end);
+}
+