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Subject[PATCH 27/43] MN10300: Make the use of PIDR to mark TLB entries controllable
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Date
From: Akira Takeuchi <takeuchi.akr@jp.panasonic.com>

Make controllable the use of the PIDR register to mark TLB entries as belonging
to particular processes.

Signed-off-by: Akira Takeuchi <takeuchi.akr@jp.panasonic.com>
Signed-off-by: Kiyoshi Owada <owada.kiyoshi@jp.panasonic.com>
Signed-off-by: David Howells <dhowells@redhat.com>
---
arch/mn10300/Kconfig | 3 ++
arch/mn10300/include/asm/mmu_context.h | 59 ++++++++++++++++----------------
arch/mn10300/include/asm/tlbflush.h | 43 ++++++++++++++++++++++-
arch/mn10300/mm/mmu-context.c | 41 ++++++----------------
4 files changed, 84 insertions(+), 62 deletions(-)

diff --git a/arch/mn10300/Kconfig b/arch/mn10300/Kconfig
index dd7b570..7bd920b 100644
--- a/arch/mn10300/Kconfig
+++ b/arch/mn10300/Kconfig
@@ -142,6 +142,9 @@ config FPU

source "arch/mn10300/mm/Kconfig.cache"

+config MN10300_TLB_USE_PIDR
+ def_bool y
+
menu "Memory layout options"

config KERNEL_RAM_BASE_ADDRESS
diff --git a/arch/mn10300/include/asm/mmu_context.h b/arch/mn10300/include/asm/mmu_context.h
index 24d63f0..5fb3648 100644
--- a/arch/mn10300/include/asm/mmu_context.h
+++ b/arch/mn10300/include/asm/mmu_context.h
@@ -27,28 +27,22 @@
#include <asm/tlbflush.h>
#include <asm-generic/mm_hooks.h>

+#define MMU_CONTEXT_TLBPID_NR 256
#define MMU_CONTEXT_TLBPID_MASK 0x000000ffUL
#define MMU_CONTEXT_VERSION_MASK 0xffffff00UL
#define MMU_CONTEXT_FIRST_VERSION 0x00000100UL
#define MMU_NO_CONTEXT 0x00000000UL
-
-extern unsigned long mmu_context_cache[NR_CPUS];
-#define mm_context(mm) (mm->context.tlbpid[smp_processor_id()])
+#define MMU_CONTEXT_TLBPID_LOCK_NR 0

#define enter_lazy_tlb(mm, tsk) do {} while (0)

-#ifdef CONFIG_SMP
-#define cpu_ran_vm(cpu, mm) \
- cpumask_set_cpu((cpu), mm_cpumask(mm))
-#define cpu_maybe_ran_vm(cpu, mm) \
- cpumask_test_and_set_cpu((cpu), mm_cpumask(mm))
-#else
-#define cpu_ran_vm(cpu, mm) do {} while (0)
-#define cpu_maybe_ran_vm(cpu, mm) true
-#endif /* CONFIG_SMP */
+#ifdef CONFIG_MN10300_TLB_USE_PIDR
+extern unsigned long mmu_context_cache[NR_CPUS];
+#define mm_context(mm) (mm->context.tlbpid[smp_processor_id()])

-/*
- * allocate an MMU context
+/**
+ * allocate_mmu_context - Allocate storage for the arch-specific MMU data
+ * @mm: The userspace VM context being set up
*/
static inline unsigned long allocate_mmu_context(struct mm_struct *mm)
{
@@ -101,34 +95,41 @@ static inline int init_new_context(struct task_struct *tsk,
}

/*
- * destroy context related info for an mm_struct that is about to be put to
- * rest
- */
-#define destroy_context(mm) do { } while (0)
-
-/*
* after we have set current->mm to a new value, this activates the context for
* the new mm so we see the new mappings.
*/
-static inline void activate_context(struct mm_struct *mm, int cpu)
+static inline void activate_context(struct mm_struct *mm)
{
PIDR = get_mmu_context(mm) & MMU_CONTEXT_TLBPID_MASK;
}
+#else /* CONFIG_MN10300_TLB_USE_PIDR */

-/*
- * change between virtual memory sets
+#define init_new_context(tsk, mm) (0)
+#define activate_context(mm) local_flush_tlb()
+
+#endif /* CONFIG_MN10300_TLB_USE_PIDR */
+
+/**
+ * destroy_context - Destroy mm context information
+ * @mm: The MM being destroyed.
+ *
+ * Destroy context related info for an mm_struct that is about to be put to
+ * rest
+ */
+#define destroy_context(mm) do {} while (0)
+
+/**
+ * switch_mm - Change between userspace virtual memory contexts
+ * @prev: The outgoing MM context.
+ * @next: The incoming MM context.
+ * @tsk: The incoming task.
*/
static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
struct task_struct *tsk)
{
- int cpu = smp_processor_id();
-
if (prev != next) {
- cpu_ran_vm(cpu, next);
- activate_context(next, cpu);
PTBR = (unsigned long) next->pgd;
- } else if (!cpu_maybe_ran_vm(cpu, next)) {
- activate_context(next, cpu);
+ activate_context(next);
}
}

diff --git a/arch/mn10300/include/asm/tlbflush.h b/arch/mn10300/include/asm/tlbflush.h
index 5d54bf5..c3c194d 100644
--- a/arch/mn10300/include/asm/tlbflush.h
+++ b/arch/mn10300/include/asm/tlbflush.h
@@ -13,6 +13,12 @@

#include <asm/processor.h>

+struct tlb_state {
+ struct mm_struct *active_mm;
+ int state;
+};
+DECLARE_PER_CPU_SHARED_ALIGNED(struct tlb_state, cpu_tlbstate);
+
/**
* local_flush_tlb - Flush the current MM's entries from the local CPU's TLBs
*/
@@ -31,20 +37,51 @@ static inline void local_flush_tlb(void)
/**
* local_flush_tlb_all - Flush all entries from the local CPU's TLBs
*/
-#define local_flush_tlb_all() local_flush_tlb()
+static inline void local_flush_tlb_all(void)
+{
+ local_flush_tlb();
+}

/**
* local_flush_tlb_one - Flush one entry from the local CPU's TLBs
*/
-#define local_flush_tlb_one(addr) local_flush_tlb()
+static inline void local_flush_tlb_one(unsigned long addr)
+{
+ local_flush_tlb();
+}

/**
* local_flush_tlb_page - Flush a page's entry from the local CPU's TLBs
* @mm: The MM to flush for
* @addr: The address of the target page in RAM (not its page struct)
*/
-extern void local_flush_tlb_page(struct mm_struct *mm, unsigned long addr);
+static inline
+void local_flush_tlb_page(struct mm_struct *mm, unsigned long addr)
+{
+ unsigned long pteu, flags, cnx;
+
+ addr &= PAGE_MASK;

+ local_irq_save(flags);
+
+ cnx = 1;
+#ifdef CONFIG_MN10300_TLB_USE_PIDR
+ cnx = mm->context.tlbpid[smp_processor_id()];
+#endif
+ if (cnx) {
+ pteu = addr;
+#ifdef CONFIG_MN10300_TLB_USE_PIDR
+ pteu |= cnx & xPTEU_PID;
+#endif
+ IPTEU = pteu;
+ DPTEU = pteu;
+ if (IPTEL & xPTEL_V)
+ IPTEL = 0;
+ if (DPTEL & xPTEL_V)
+ DPTEL = 0;
+ }
+ local_irq_restore(flags);
+}

/*
* TLB flushing:
diff --git a/arch/mn10300/mm/mmu-context.c b/arch/mn10300/mm/mmu-context.c
index 3d83966..a4f7d3d 100644
--- a/arch/mn10300/mm/mmu-context.c
+++ b/arch/mn10300/mm/mmu-context.c
@@ -13,40 +13,15 @@
#include <asm/mmu_context.h>
#include <asm/tlbflush.h>

+#ifdef CONFIG_MN10300_TLB_USE_PIDR
/*
* list of the MMU contexts last allocated on each CPU
*/
unsigned long mmu_context_cache[NR_CPUS] = {
- [0 ... NR_CPUS - 1] = MMU_CONTEXT_FIRST_VERSION * 2 - 1,
+ [0 ... NR_CPUS - 1] =
+ MMU_CONTEXT_FIRST_VERSION * 2 - (1 - MMU_CONTEXT_TLBPID_LOCK_NR),
};
-
-/*
- * flush the specified TLB entry
- */
-void local_flush_tlb_page(struct mm_struct *mm, unsigned long addr)
-{
- unsigned long pteu, cnx, flags;
-
- addr &= PAGE_MASK;
-
- /* make sure the context doesn't migrate and defend against
- * interference from vmalloc'd regions */
- local_irq_save(flags);
-
- cnx = mm_context(mm);
-
- if (cnx != MMU_NO_CONTEXT) {
- pteu = addr | (cnx & 0x000000ffUL);
- IPTEU = pteu;
- DPTEU = pteu;
- if (IPTEL & xPTEL_V)
- IPTEL = 0;
- if (DPTEL & xPTEL_V)
- DPTEL = 0;
- }
-
- local_irq_restore(flags);
-}
+#endif /* CONFIG_MN10300_TLB_USE_PIDR */

/*
* preemptively set a TLB entry
@@ -63,10 +38,16 @@ void update_mmu_cache(struct vm_area_struct *vma, unsigned long addr, pte_t *pte
* interference from vmalloc'd regions */
local_irq_save(flags);

+ cnx = ~MMU_NO_CONTEXT;
+#ifdef CONFIG_MN10300_TLB_USE_PIDR
cnx = mm_context(vma->vm_mm);
+#endif

if (cnx != MMU_NO_CONTEXT) {
- pteu = addr | (cnx & 0x000000ffUL);
+ pteu = addr;
+#ifdef CONFIG_MN10300_TLB_USE_PIDR
+ pteu |= cnx & MMU_CONTEXT_TLBPID_MASK;
+#endif
if (!(pte_val(pte) & _PAGE_NX)) {
IPTEU = pteu;
if (IPTEL & xPTEL_V)


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