Changeset 454f1da in mainline for kernel/arch/sparc64/src/mm/cache.c

Timestamp:

2007-03-26T19:35:28Z (18 years ago)

Author:

Jakub Jermar <jakub@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

5d7daff

Parents:

4638401

Message:

Reworked handling of illegal virtual aliases caused by frame reuse.
We moved the incomplete handling from backend's frame method to
backend's page_fault method. The page_fault method is the one that
can create an illegal alias if it writes the userspace frame using
kernel address with a different page color than the page to which is
this frame mapped in userspace. When we detect this, we do D-cache
shootdown on all processors (!!!).

If we add code that accesses userspace memory from kernel address
space, we will have to check for illegal virtual aliases at all such
places.

I tested this on a 4-way simulated E6500 and a real-world Ultra 5,
which has unfortunatelly only one processor.

This solves ticket #26.

File:

• kernel/arch/sparc64/src/mm/cache.c (modified) (1 diff)

kernel/arch/sparc64/src/mm/cache.c

@@ -32 +32 @@
 /**
  * @file
+ * @brief       D-cache shootdown algorithm.
  */
 
 #include <arch/mm/cache.h>
 
+#ifdef CONFIG_SMP
+#ifdef CONFIG_VIRT_IDX_DCACHE
+
+#include <smp/ipi.h>
+#include <arch/interrupt.h>
+#include <synch/spinlock.h>
+#include <arch.h>
+#include <debug.h>
+
+/**
+ * This spinlock is used by the processors to synchronize during the D-cache
+ * shootdown.
+ */
+SPINLOCK_INITIALIZE(dcachelock);
+
+/** Initialize the D-cache shootdown sequence.
+ *
+ * Start the shootdown sequence by sending out an IPI and wait until all
+ * processors spin on the dcachelock spinlock.
+ *
+ * @param type  Scope of the D-cache shootdown.
+ * @param color Color to be invalidated; applicable only for DCACHE_INVL_COLOR
+ *              and DCACHE_INVL_FRAME invalidation types.
+ * @param frame Frame to be invalidated; applicable only for DCACHE_INVL_FRAME
+ *              invalidation types.
+ */
+void dcache_shootdown_start(dcache_invalidate_type_t type, int color,
+    uintptr_t frame)
+{
+        int i;
+
+        CPU->arch.dcache_active = 0;
+        spinlock_lock(&dcachelock);
+
+        for (i = 0; i < config.cpu_count; i++) {
+                cpu_t *cpu;
+
+                if (i == CPU->id)
+                        continue;
+
+                cpu = &cpus[i];
+                spinlock_lock(&cpu->lock);
+                if (cpu->arch.dcache_message_count ==
+                    DCACHE_MSG_QUEUE_LEN) {
+                        /*
+                         * The queue is full, flush the cache entirely.
+                         */
+                        cpu->arch.dcache_message_count = 1;
+                        cpu->arch.dcache_messages[0].type = DCACHE_INVL_ALL;
+                        cpu->arch.dcache_messages[0].color = 0; /* ignored */
+                        cpu->arch.dcache_messages[0].frame = 0; /* ignored */
+                } else {
+                        index_t idx = cpu->arch.dcache_message_count++;
+                        cpu->arch.dcache_messages[idx].type = type;
+                        cpu->arch.dcache_messages[idx].color = color;
+                        cpu->arch.dcache_messages[idx].frame = frame;
+                }
+                spinlock_unlock(&cpu->lock);
+        }
+
+        ipi_broadcast(IPI_DCACHE_SHOOTDOWN);    
+
+busy_wait:
+        for (i = 0; i < config.cpu_count; i++)
+                if (cpus[i].arch.dcache_active)
+                        goto busy_wait;
+}
+
+/** Finish the D-cache shootdown sequence. */
+void dcache_shootdown_finalize(void)
+{
+        spinlock_unlock(&dcachelock);
+        CPU->arch.dcache_active = 1;
+}
+
+/** Process the D-cache shootdown IPI. */
+void dcache_shootdown_ipi_recv(void)
+{
+        int i;
+
+        ASSERT(CPU);
+
+        CPU->arch.dcache_active = 0;
+        spinlock_lock(&dcachelock);
+        spinlock_unlock(&dcachelock);
+        
+        spinlock_lock(&CPU->lock);
+        ASSERT(CPU->arch.dcache_message_count < DCACHE_MSG_QUEUE_LEN);
+        for (i = 0; i < CPU->arch.dcache_message_count; i++) {
+                switch (CPU->arch.dcache_messages[i].type) {
+                case DCACHE_INVL_ALL:
+                        dcache_flush();
+                        goto flushed;
+                        break;
+                case DCACHE_INVL_COLOR:
+                        dcache_flush_color(CPU->arch.dcache_messages[i].color);
+                        break;
+                case DCACHE_INVL_FRAME:
+                        dcache_flush_frame(CPU->arch.dcache_messages[i].color,
+                            CPU->arch.dcache_messages[i].frame);
+                        break;
+                default:
+                        panic("unknown type (%d)\n",
+                            CPU->arch.dcache_messages[i].type);
+                }
+        }
+flushed:
+        CPU->arch.dcache_message_count = 0;
+        spinlock_unlock(&CPU->lock);
+
+        CPU->arch.dcache_active = 1;
+}
+
+#endif /* CONFIG_VIRT_IDX_DCACHE */
+#endif /* CONFIG_SMP */
+
 /** @}
  */