![David S. Miller](/assets/img/avatar_default.png)
When CONFIG_BUG is turned off, the standard trick of: switch (x) { case X: ... case Y: ... default: BUG(); }; to mark impossible cases does not work because BUG() evalutes to nothing and thus GCC just sees a fallthrough code path. Add an explicit KERN_ERR log message and a do_exit() to trap this case. Signed-off-by: David S. Miller <davem@davemloft.net>
501 lines
13 KiB
C
501 lines
13 KiB
C
/* arch/sparc64/mm/tsb.c
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*
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* Copyright (C) 2006 David S. Miller <davem@davemloft.net>
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*/
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#include <linux/kernel.h>
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#include <asm/system.h>
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#include <asm/page.h>
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#include <asm/tlbflush.h>
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#include <asm/tlb.h>
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#include <asm/mmu_context.h>
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#include <asm/pgtable.h>
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#include <asm/tsb.h>
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#include <asm/oplib.h>
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extern struct tsb swapper_tsb[KERNEL_TSB_NENTRIES];
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static inline unsigned long tsb_hash(unsigned long vaddr, unsigned long hash_shift, unsigned long nentries)
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{
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vaddr >>= hash_shift;
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return vaddr & (nentries - 1);
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}
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static inline int tag_compare(unsigned long tag, unsigned long vaddr)
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{
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return (tag == (vaddr >> 22));
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}
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/* TSB flushes need only occur on the processor initiating the address
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* space modification, not on each cpu the address space has run on.
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* Only the TLB flush needs that treatment.
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*/
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void flush_tsb_kernel_range(unsigned long start, unsigned long end)
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{
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unsigned long v;
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for (v = start; v < end; v += PAGE_SIZE) {
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unsigned long hash = tsb_hash(v, PAGE_SHIFT,
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KERNEL_TSB_NENTRIES);
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struct tsb *ent = &swapper_tsb[hash];
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if (tag_compare(ent->tag, v)) {
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ent->tag = (1UL << TSB_TAG_INVALID_BIT);
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membar_storeload_storestore();
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}
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}
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}
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static void __flush_tsb_one(struct mmu_gather *mp, unsigned long hash_shift, unsigned long tsb, unsigned long nentries)
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{
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unsigned long i;
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for (i = 0; i < mp->tlb_nr; i++) {
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unsigned long v = mp->vaddrs[i];
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unsigned long tag, ent, hash;
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v &= ~0x1UL;
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hash = tsb_hash(v, hash_shift, nentries);
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ent = tsb + (hash * sizeof(struct tsb));
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tag = (v >> 22UL);
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tsb_flush(ent, tag);
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}
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}
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void flush_tsb_user(struct mmu_gather *mp)
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{
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struct mm_struct *mm = mp->mm;
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unsigned long nentries, base, flags;
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spin_lock_irqsave(&mm->context.lock, flags);
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base = (unsigned long) mm->context.tsb_block[MM_TSB_BASE].tsb;
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nentries = mm->context.tsb_block[MM_TSB_BASE].tsb_nentries;
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if (tlb_type == cheetah_plus || tlb_type == hypervisor)
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base = __pa(base);
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__flush_tsb_one(mp, PAGE_SHIFT, base, nentries);
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#ifdef CONFIG_HUGETLB_PAGE
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if (mm->context.tsb_block[MM_TSB_HUGE].tsb) {
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base = (unsigned long) mm->context.tsb_block[MM_TSB_HUGE].tsb;
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nentries = mm->context.tsb_block[MM_TSB_HUGE].tsb_nentries;
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if (tlb_type == cheetah_plus || tlb_type == hypervisor)
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base = __pa(base);
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__flush_tsb_one(mp, HPAGE_SHIFT, base, nentries);
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}
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#endif
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spin_unlock_irqrestore(&mm->context.lock, flags);
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}
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#if defined(CONFIG_SPARC64_PAGE_SIZE_8KB)
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#define HV_PGSZ_IDX_BASE HV_PGSZ_IDX_8K
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#define HV_PGSZ_MASK_BASE HV_PGSZ_MASK_8K
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#elif defined(CONFIG_SPARC64_PAGE_SIZE_64KB)
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#define HV_PGSZ_IDX_BASE HV_PGSZ_IDX_64K
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#define HV_PGSZ_MASK_BASE HV_PGSZ_MASK_64K
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#elif defined(CONFIG_SPARC64_PAGE_SIZE_512KB)
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#define HV_PGSZ_IDX_BASE HV_PGSZ_IDX_512K
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#define HV_PGSZ_MASK_BASE HV_PGSZ_MASK_512K
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#elif defined(CONFIG_SPARC64_PAGE_SIZE_4MB)
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#define HV_PGSZ_IDX_BASE HV_PGSZ_IDX_4MB
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#define HV_PGSZ_MASK_BASE HV_PGSZ_MASK_4MB
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#else
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#error Broken base page size setting...
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#endif
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#ifdef CONFIG_HUGETLB_PAGE
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#if defined(CONFIG_HUGETLB_PAGE_SIZE_64K)
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#define HV_PGSZ_IDX_HUGE HV_PGSZ_IDX_64K
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#define HV_PGSZ_MASK_HUGE HV_PGSZ_MASK_64K
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#elif defined(CONFIG_HUGETLB_PAGE_SIZE_512K)
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#define HV_PGSZ_IDX_HUGE HV_PGSZ_IDX_512K
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#define HV_PGSZ_MASK_HUGE HV_PGSZ_MASK_512K
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#elif defined(CONFIG_HUGETLB_PAGE_SIZE_4MB)
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#define HV_PGSZ_IDX_HUGE HV_PGSZ_IDX_4MB
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#define HV_PGSZ_MASK_HUGE HV_PGSZ_MASK_4MB
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#else
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#error Broken huge page size setting...
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#endif
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#endif
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static void setup_tsb_params(struct mm_struct *mm, unsigned long tsb_idx, unsigned long tsb_bytes)
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{
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unsigned long tsb_reg, base, tsb_paddr;
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unsigned long page_sz, tte;
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mm->context.tsb_block[tsb_idx].tsb_nentries =
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tsb_bytes / sizeof(struct tsb);
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base = TSBMAP_BASE;
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tte = pgprot_val(PAGE_KERNEL_LOCKED);
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tsb_paddr = __pa(mm->context.tsb_block[tsb_idx].tsb);
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BUG_ON(tsb_paddr & (tsb_bytes - 1UL));
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/* Use the smallest page size that can map the whole TSB
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* in one TLB entry.
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*/
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switch (tsb_bytes) {
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case 8192 << 0:
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tsb_reg = 0x0UL;
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#ifdef DCACHE_ALIASING_POSSIBLE
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base += (tsb_paddr & 8192);
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#endif
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page_sz = 8192;
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break;
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case 8192 << 1:
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tsb_reg = 0x1UL;
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page_sz = 64 * 1024;
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break;
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case 8192 << 2:
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tsb_reg = 0x2UL;
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page_sz = 64 * 1024;
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break;
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case 8192 << 3:
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tsb_reg = 0x3UL;
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page_sz = 64 * 1024;
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break;
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case 8192 << 4:
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tsb_reg = 0x4UL;
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page_sz = 512 * 1024;
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break;
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case 8192 << 5:
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tsb_reg = 0x5UL;
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page_sz = 512 * 1024;
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break;
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case 8192 << 6:
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tsb_reg = 0x6UL;
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page_sz = 512 * 1024;
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break;
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case 8192 << 7:
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tsb_reg = 0x7UL;
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page_sz = 4 * 1024 * 1024;
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break;
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default:
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printk(KERN_ERR "TSB[%s:%d]: Impossible TSB size %lu, killing process.\n",
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current->comm, current->pid, tsb_bytes);
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do_exit(SIGSEGV);
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};
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tte |= pte_sz_bits(page_sz);
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if (tlb_type == cheetah_plus || tlb_type == hypervisor) {
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/* Physical mapping, no locked TLB entry for TSB. */
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tsb_reg |= tsb_paddr;
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mm->context.tsb_block[tsb_idx].tsb_reg_val = tsb_reg;
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mm->context.tsb_block[tsb_idx].tsb_map_vaddr = 0;
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mm->context.tsb_block[tsb_idx].tsb_map_pte = 0;
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} else {
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tsb_reg |= base;
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tsb_reg |= (tsb_paddr & (page_sz - 1UL));
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tte |= (tsb_paddr & ~(page_sz - 1UL));
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mm->context.tsb_block[tsb_idx].tsb_reg_val = tsb_reg;
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mm->context.tsb_block[tsb_idx].tsb_map_vaddr = base;
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mm->context.tsb_block[tsb_idx].tsb_map_pte = tte;
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}
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/* Setup the Hypervisor TSB descriptor. */
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if (tlb_type == hypervisor) {
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struct hv_tsb_descr *hp = &mm->context.tsb_descr[tsb_idx];
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switch (tsb_idx) {
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case MM_TSB_BASE:
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hp->pgsz_idx = HV_PGSZ_IDX_BASE;
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break;
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#ifdef CONFIG_HUGETLB_PAGE
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case MM_TSB_HUGE:
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hp->pgsz_idx = HV_PGSZ_IDX_HUGE;
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break;
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#endif
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default:
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BUG();
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};
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hp->assoc = 1;
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hp->num_ttes = tsb_bytes / 16;
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hp->ctx_idx = 0;
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switch (tsb_idx) {
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case MM_TSB_BASE:
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hp->pgsz_mask = HV_PGSZ_MASK_BASE;
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break;
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#ifdef CONFIG_HUGETLB_PAGE
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case MM_TSB_HUGE:
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hp->pgsz_mask = HV_PGSZ_MASK_HUGE;
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break;
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#endif
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default:
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BUG();
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};
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hp->tsb_base = tsb_paddr;
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hp->resv = 0;
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}
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}
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static struct kmem_cache *tsb_caches[8] __read_mostly;
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static const char *tsb_cache_names[8] = {
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"tsb_8KB",
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"tsb_16KB",
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"tsb_32KB",
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"tsb_64KB",
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"tsb_128KB",
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"tsb_256KB",
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"tsb_512KB",
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"tsb_1MB",
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};
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void __init pgtable_cache_init(void)
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{
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unsigned long i;
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for (i = 0; i < 8; i++) {
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unsigned long size = 8192 << i;
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const char *name = tsb_cache_names[i];
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tsb_caches[i] = kmem_cache_create(name,
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size, size,
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0, NULL);
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if (!tsb_caches[i]) {
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prom_printf("Could not create %s cache\n", name);
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prom_halt();
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}
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}
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}
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/* When the RSS of an address space exceeds tsb_rss_limit for a TSB,
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* do_sparc64_fault() invokes this routine to try and grow it.
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*
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* When we reach the maximum TSB size supported, we stick ~0UL into
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* tsb_rss_limit for that TSB so the grow checks in do_sparc64_fault()
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* will not trigger any longer.
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*
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* The TSB can be anywhere from 8K to 1MB in size, in increasing powers
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* of two. The TSB must be aligned to it's size, so f.e. a 512K TSB
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* must be 512K aligned. It also must be physically contiguous, so we
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* cannot use vmalloc().
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*
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* The idea here is to grow the TSB when the RSS of the process approaches
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* the number of entries that the current TSB can hold at once. Currently,
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* we trigger when the RSS hits 3/4 of the TSB capacity.
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*/
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void tsb_grow(struct mm_struct *mm, unsigned long tsb_index, unsigned long rss)
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{
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unsigned long max_tsb_size = 1 * 1024 * 1024;
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unsigned long new_size, old_size, flags;
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struct tsb *old_tsb, *new_tsb;
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unsigned long new_cache_index, old_cache_index;
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unsigned long new_rss_limit;
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gfp_t gfp_flags;
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if (max_tsb_size > (PAGE_SIZE << MAX_ORDER))
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max_tsb_size = (PAGE_SIZE << MAX_ORDER);
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new_cache_index = 0;
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for (new_size = 8192; new_size < max_tsb_size; new_size <<= 1UL) {
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unsigned long n_entries = new_size / sizeof(struct tsb);
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n_entries = (n_entries * 3) / 4;
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if (n_entries > rss)
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break;
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new_cache_index++;
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}
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if (new_size == max_tsb_size)
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new_rss_limit = ~0UL;
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else
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new_rss_limit = ((new_size / sizeof(struct tsb)) * 3) / 4;
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retry_tsb_alloc:
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gfp_flags = GFP_KERNEL;
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if (new_size > (PAGE_SIZE * 2))
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gfp_flags = __GFP_NOWARN | __GFP_NORETRY;
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new_tsb = kmem_cache_alloc(tsb_caches[new_cache_index], gfp_flags);
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if (unlikely(!new_tsb)) {
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/* Not being able to fork due to a high-order TSB
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* allocation failure is very bad behavior. Just back
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* down to a 0-order allocation and force no TSB
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* growing for this address space.
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*/
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if (mm->context.tsb_block[tsb_index].tsb == NULL &&
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new_cache_index > 0) {
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new_cache_index = 0;
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new_size = 8192;
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new_rss_limit = ~0UL;
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goto retry_tsb_alloc;
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}
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/* If we failed on a TSB grow, we are under serious
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* memory pressure so don't try to grow any more.
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*/
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if (mm->context.tsb_block[tsb_index].tsb != NULL)
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mm->context.tsb_block[tsb_index].tsb_rss_limit = ~0UL;
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return;
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}
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/* Mark all tags as invalid. */
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tsb_init(new_tsb, new_size);
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/* Ok, we are about to commit the changes. If we are
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* growing an existing TSB the locking is very tricky,
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* so WATCH OUT!
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*
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* We have to hold mm->context.lock while committing to the
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* new TSB, this synchronizes us with processors in
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* flush_tsb_user() and switch_mm() for this address space.
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*
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* But even with that lock held, processors run asynchronously
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* accessing the old TSB via TLB miss handling. This is OK
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* because those actions are just propagating state from the
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* Linux page tables into the TSB, page table mappings are not
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* being changed. If a real fault occurs, the processor will
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* synchronize with us when it hits flush_tsb_user(), this is
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* also true for the case where vmscan is modifying the page
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* tables. The only thing we need to be careful with is to
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* skip any locked TSB entries during copy_tsb().
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*
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* When we finish committing to the new TSB, we have to drop
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* the lock and ask all other cpus running this address space
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* to run tsb_context_switch() to see the new TSB table.
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*/
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spin_lock_irqsave(&mm->context.lock, flags);
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old_tsb = mm->context.tsb_block[tsb_index].tsb;
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old_cache_index =
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(mm->context.tsb_block[tsb_index].tsb_reg_val & 0x7UL);
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old_size = (mm->context.tsb_block[tsb_index].tsb_nentries *
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sizeof(struct tsb));
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/* Handle multiple threads trying to grow the TSB at the same time.
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* One will get in here first, and bump the size and the RSS limit.
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* The others will get in here next and hit this check.
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*/
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if (unlikely(old_tsb &&
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(rss < mm->context.tsb_block[tsb_index].tsb_rss_limit))) {
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spin_unlock_irqrestore(&mm->context.lock, flags);
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kmem_cache_free(tsb_caches[new_cache_index], new_tsb);
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return;
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}
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mm->context.tsb_block[tsb_index].tsb_rss_limit = new_rss_limit;
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if (old_tsb) {
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extern void copy_tsb(unsigned long old_tsb_base,
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unsigned long old_tsb_size,
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unsigned long new_tsb_base,
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unsigned long new_tsb_size);
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unsigned long old_tsb_base = (unsigned long) old_tsb;
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unsigned long new_tsb_base = (unsigned long) new_tsb;
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if (tlb_type == cheetah_plus || tlb_type == hypervisor) {
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old_tsb_base = __pa(old_tsb_base);
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new_tsb_base = __pa(new_tsb_base);
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}
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copy_tsb(old_tsb_base, old_size, new_tsb_base, new_size);
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}
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mm->context.tsb_block[tsb_index].tsb = new_tsb;
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setup_tsb_params(mm, tsb_index, new_size);
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spin_unlock_irqrestore(&mm->context.lock, flags);
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/* If old_tsb is NULL, we're being invoked for the first time
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* from init_new_context().
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*/
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if (old_tsb) {
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/* Reload it on the local cpu. */
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tsb_context_switch(mm);
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/* Now force other processors to do the same. */
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smp_tsb_sync(mm);
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/* Now it is safe to free the old tsb. */
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kmem_cache_free(tsb_caches[old_cache_index], old_tsb);
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}
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}
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int init_new_context(struct task_struct *tsk, struct mm_struct *mm)
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{
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#ifdef CONFIG_HUGETLB_PAGE
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unsigned long huge_pte_count;
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#endif
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unsigned int i;
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spin_lock_init(&mm->context.lock);
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mm->context.sparc64_ctx_val = 0UL;
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#ifdef CONFIG_HUGETLB_PAGE
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/* We reset it to zero because the fork() page copying
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* will re-increment the counters as the parent PTEs are
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* copied into the child address space.
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*/
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huge_pte_count = mm->context.huge_pte_count;
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mm->context.huge_pte_count = 0;
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#endif
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/* copy_mm() copies over the parent's mm_struct before calling
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* us, so we need to zero out the TSB pointer or else tsb_grow()
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* will be confused and think there is an older TSB to free up.
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*/
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for (i = 0; i < MM_NUM_TSBS; i++)
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mm->context.tsb_block[i].tsb = NULL;
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/* If this is fork, inherit the parent's TSB size. We would
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* grow it to that size on the first page fault anyways.
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*/
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tsb_grow(mm, MM_TSB_BASE, get_mm_rss(mm));
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#ifdef CONFIG_HUGETLB_PAGE
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if (unlikely(huge_pte_count))
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tsb_grow(mm, MM_TSB_HUGE, huge_pte_count);
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#endif
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if (unlikely(!mm->context.tsb_block[MM_TSB_BASE].tsb))
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return -ENOMEM;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void tsb_destroy_one(struct tsb_config *tp)
|
|
{
|
|
unsigned long cache_index;
|
|
|
|
if (!tp->tsb)
|
|
return;
|
|
cache_index = tp->tsb_reg_val & 0x7UL;
|
|
kmem_cache_free(tsb_caches[cache_index], tp->tsb);
|
|
tp->tsb = NULL;
|
|
tp->tsb_reg_val = 0UL;
|
|
}
|
|
|
|
void destroy_context(struct mm_struct *mm)
|
|
{
|
|
unsigned long flags, i;
|
|
|
|
for (i = 0; i < MM_NUM_TSBS; i++)
|
|
tsb_destroy_one(&mm->context.tsb_block[i]);
|
|
|
|
spin_lock_irqsave(&ctx_alloc_lock, flags);
|
|
|
|
if (CTX_VALID(mm->context)) {
|
|
unsigned long nr = CTX_NRBITS(mm->context);
|
|
mmu_context_bmap[nr>>6] &= ~(1UL << (nr & 63));
|
|
}
|
|
|
|
spin_unlock_irqrestore(&ctx_alloc_lock, flags);
|
|
}
|