--- /dev/null
+#ifndef __ALPHA_MMU_CONTEXT_H
+#define __ALPHA_MMU_CONTEXT_H
+
+/*
+ * get a new mmu context..
+ *
+ * Copyright (C) 1996, Linus Torvalds
+ */
+
+#include <asm/machvec.h>
+#include <asm/compiler.h>
+#include <asm-generic/mm_hooks.h>
+
+/*
+ * Force a context reload. This is needed when we change the page
+ * table pointer or when we update the ASN of the current process.
+ */
+
+/* Don't get into trouble with dueling __EXTERN_INLINEs. */
+#ifndef __EXTERN_INLINE
+#include <asm/io.h>
+#endif
+
+
+static inline unsigned long
+__reload_thread(struct pcb_struct *pcb)
+{
+ register unsigned long a0 __asm__("$16");
+ register unsigned long v0 __asm__("$0");
+
+ a0 = virt_to_phys(pcb);
+ __asm__ __volatile__(
+ "call_pal %2 #__reload_thread"
+ : "=r"(v0), "=r"(a0)
+ : "i"(PAL_swpctx), "r"(a0)
+ : "$1", "$22", "$23", "$24", "$25");
+
+ return v0;
+}
+
+
+/*
+ * The maximum ASN's the processor supports. On the EV4 this is 63
+ * but the PAL-code doesn't actually use this information. On the
+ * EV5 this is 127, and EV6 has 255.
+ *
+ * On the EV4, the ASNs are more-or-less useless anyway, as they are
+ * only used as an icache tag, not for TB entries. On the EV5 and EV6,
+ * ASN's also validate the TB entries, and thus make a lot more sense.
+ *
+ * The EV4 ASN's don't even match the architecture manual, ugh. And
+ * I quote: "If a processor implements address space numbers (ASNs),
+ * and the old PTE has the Address Space Match (ASM) bit clear (ASNs
+ * in use) and the Valid bit set, then entries can also effectively be
+ * made coherent by assigning a new, unused ASN to the currently
+ * running process and not reusing the previous ASN before calling the
+ * appropriate PALcode routine to invalidate the translation buffer (TB)".
+ *
+ * In short, the EV4 has a "kind of" ASN capability, but it doesn't actually
+ * work correctly and can thus not be used (explaining the lack of PAL-code
+ * support).
+ */
+#define EV4_MAX_ASN 63
+#define EV5_MAX_ASN 127
+#define EV6_MAX_ASN 255
+
+#ifdef CONFIG_ALPHA_GENERIC
+# define MAX_ASN (alpha_mv.max_asn)
+#else
+# ifdef CONFIG_ALPHA_EV4
+# define MAX_ASN EV4_MAX_ASN
+# elif defined(CONFIG_ALPHA_EV5)
+# define MAX_ASN EV5_MAX_ASN
+# else
+# define MAX_ASN EV6_MAX_ASN
+# endif
+#endif
+
+/*
+ * cpu_last_asn(processor):
+ * 63 0
+ * +-------------+----------------+--------------+
+ * | asn version | this processor | hardware asn |
+ * +-------------+----------------+--------------+
+ */
+
+#include <asm/smp.h>
+#ifdef CONFIG_SMP
+#define cpu_last_asn(cpuid) (cpu_data[cpuid].last_asn)
+#else
+extern unsigned long last_asn;
+#define cpu_last_asn(cpuid) last_asn
+#endif /* CONFIG_SMP */
+
+#define WIDTH_HARDWARE_ASN 8
+#define ASN_FIRST_VERSION (1UL << WIDTH_HARDWARE_ASN)
+#define HARDWARE_ASN_MASK ((1UL << WIDTH_HARDWARE_ASN) - 1)
+
+/*
+ * NOTE! The way this is set up, the high bits of the "asn_cache" (and
+ * the "mm->context") are the ASN _version_ code. A version of 0 is
+ * always considered invalid, so to invalidate another process you only
+ * need to do "p->mm->context = 0".
+ *
+ * If we need more ASN's than the processor has, we invalidate the old
+ * user TLB's (tbiap()) and start a new ASN version. That will automatically
+ * force a new asn for any other processes the next time they want to
+ * run.
+ */
+
+#ifndef __EXTERN_INLINE
+#define __EXTERN_INLINE extern inline
+#define __MMU_EXTERN_INLINE
+#endif
+
+extern inline unsigned long
+__get_new_mm_context(struct mm_struct *mm, long cpu)
+{
+ unsigned long asn = cpu_last_asn(cpu);
+ unsigned long next = asn + 1;
+
+ if ((asn & HARDWARE_ASN_MASK) >= MAX_ASN) {
+ tbiap();
+ imb();
+ next = (asn & ~HARDWARE_ASN_MASK) + ASN_FIRST_VERSION;
+ }
+ cpu_last_asn(cpu) = next;
+ return next;
+}
+
+__EXTERN_INLINE void
+ev5_switch_mm(struct mm_struct *prev_mm, struct mm_struct *next_mm,
+ struct task_struct *next)
+{
+ /* Check if our ASN is of an older version, and thus invalid. */
+ unsigned long asn;
+ unsigned long mmc;
+ long cpu = smp_processor_id();
+
+#ifdef CONFIG_SMP
+ cpu_data[cpu].asn_lock = 1;
+ barrier();
+#endif
+ asn = cpu_last_asn(cpu);
+ mmc = next_mm->context[cpu];
+ if ((mmc ^ asn) & ~HARDWARE_ASN_MASK) {
+ mmc = __get_new_mm_context(next_mm, cpu);
+ next_mm->context[cpu] = mmc;
+ }
+#ifdef CONFIG_SMP
+ else
+ cpu_data[cpu].need_new_asn = 1;
+#endif
+
+ /* Always update the PCB ASN. Another thread may have allocated
+ a new mm->context (via flush_tlb_mm) without the ASN serial
+ number wrapping. We have no way to detect when this is needed. */
+ task_thread_info(next)->pcb.asn = mmc & HARDWARE_ASN_MASK;
+}
+
+__EXTERN_INLINE void
+ev4_switch_mm(struct mm_struct *prev_mm, struct mm_struct *next_mm,
+ struct task_struct *next)
+{
+ /* As described, ASN's are broken for TLB usage. But we can
+ optimize for switching between threads -- if the mm is
+ unchanged from current we needn't flush. */
+ /* ??? May not be needed because EV4 PALcode recognizes that
+ ASN's are broken and does a tbiap itself on swpctx, under
+ the "Must set ASN or flush" rule. At least this is true
+ for a 1992 SRM, reports Joseph Martin (jmartin@hlo.dec.com).
+ I'm going to leave this here anyway, just to Be Sure. -- r~ */
+ if (prev_mm != next_mm)
+ tbiap();
+
+ /* Do continue to allocate ASNs, because we can still use them
+ to avoid flushing the icache. */
+ ev5_switch_mm(prev_mm, next_mm, next);
+}
+
+extern void __load_new_mm_context(struct mm_struct *);
+
+#ifdef CONFIG_SMP
+#define check_mmu_context() \
+do { \
+ int cpu = smp_processor_id(); \
+ cpu_data[cpu].asn_lock = 0; \
+ barrier(); \
+ if (cpu_data[cpu].need_new_asn) { \
+ struct mm_struct * mm = current->active_mm; \
+ cpu_data[cpu].need_new_asn = 0; \
+ if (!mm->context[cpu]) \
+ __load_new_mm_context(mm); \
+ } \
+} while(0)
+#else
+#define check_mmu_context() do { } while(0)
+#endif
+
+__EXTERN_INLINE void
+ev5_activate_mm(struct mm_struct *prev_mm, struct mm_struct *next_mm)
+{
+ __load_new_mm_context(next_mm);
+}
+
+__EXTERN_INLINE void
+ev4_activate_mm(struct mm_struct *prev_mm, struct mm_struct *next_mm)
+{
+ __load_new_mm_context(next_mm);
+ tbiap();
+}
+
+#define deactivate_mm(tsk,mm) do { } while (0)
+
+#ifdef CONFIG_ALPHA_GENERIC
+# define switch_mm(a,b,c) alpha_mv.mv_switch_mm((a),(b),(c))
+# define activate_mm(x,y) alpha_mv.mv_activate_mm((x),(y))
+#else
+# ifdef CONFIG_ALPHA_EV4
+# define switch_mm(a,b,c) ev4_switch_mm((a),(b),(c))
+# define activate_mm(x,y) ev4_activate_mm((x),(y))
+# else
+# define switch_mm(a,b,c) ev5_switch_mm((a),(b),(c))
+# define activate_mm(x,y) ev5_activate_mm((x),(y))
+# endif
+#endif
+
+static inline int
+init_new_context(struct task_struct *tsk, struct mm_struct *mm)
+{
+ int i;
+
+ for_each_online_cpu(i)
+ mm->context[i] = 0;
+ if (tsk != current)
+ task_thread_info(tsk)->pcb.ptbr
+ = ((unsigned long)mm->pgd - IDENT_ADDR) >> PAGE_SHIFT;
+ return 0;
+}
+
+extern inline void
+destroy_context(struct mm_struct *mm)
+{
+ /* Nothing to do. */
+}
+
+static inline void
+enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk)
+{
+ task_thread_info(tsk)->pcb.ptbr
+ = ((unsigned long)mm->pgd - IDENT_ADDR) >> PAGE_SHIFT;
+}
+
+#ifdef __MMU_EXTERN_INLINE
+#undef __EXTERN_INLINE
+#undef __MMU_EXTERN_INLINE
+#endif
+
+#endif /* __ALPHA_MMU_CONTEXT_H */
Code Review / kvmfornfv.git / blobdiff