X-Git-Url: http://v3vee.org/palacios/gitweb/gitweb.cgi?p=palacios.git;a=blobdiff_plain;f=misc%2Ftest_vm%2Fsrc%2Fgeekos%2Fidt.c;fp=misc%2Ftest_vm%2Fsrc%2Fgeekos%2Fidt.c;h=5e2398961b6a56630cd5bb2d4aacf6f734bebaa5;hp=0000000000000000000000000000000000000000;hb=ddc16b0737cf58f7aa90a69c6652cdf4090aec51;hpb=626595465a2c6987606a6bc697df65130ad8c2d3

diff --git a/misc/test_vm/src/geekos/idt.c b/misc/test_vm/src/geekos/idt.c
new file mode 100644
index 0000000..5e23989
--- /dev/null
+++ b/misc/test_vm/src/geekos/idt.c
@@ -0,0 +1,172 @@
+/*
+ * GeekOS IDT initialization code
+ * Copyright (c) 2001, David H. Hovemeyer <daveho@cs.umd.edu>
+ * $Revision: 1.1 $
+ * 
+ * This is free software.  You are permitted to use,
+ * redistribute, and modify it as specified in the file "COPYING".
+ */
+
+#include <geekos/kassert.h>
+#include <geekos/defs.h>
+#include <geekos/idt.h>
+#include <geekos/serial.h>
+
+/* ----------------------------------------------------------------------
+ * Private data and functions
+ * ---------------------------------------------------------------------- */
+
+/*
+ * Allocated
+ */
+static union IDT_Descriptor s_IDT[ NUM_IDT_ENTRIES ];
+
+// JRL: why??? Should just call Alloc_Page(), otherwise we have dependencies all over the place
+//static union IDT_Descriptor *s_IDT = (union IDT_Descriptor *)IDT_LOCATION;
+
+/*
+ * These symbols are defined in lowlevel.asm, and define the
+ * size of the interrupt entry point table and the sizes
+ * of the individual entry points.  This gives us sufficient
+ * information to build the IDT.
+ */
+extern char g_entryPointTableStart, g_entryPointTableEnd;
+extern int g_handlerSizeNoErr, g_handlerSizeErr;
+
+/*
+ * Table of C interrupt handler functions.
+ * Note that this is public only because it is used
+ * in lowlevel.asm.  Other code should not refer to it.
+ */
+Interrupt_Handler g_interruptTable[ NUM_IDT_ENTRIES ];
+
+
+
+void DumpIDT()
+{
+  int i;
+  Print("IDT Contents:\n");
+
+  for (i=0;i<NUM_IDT_ENTRIES/16;i++) { 
+    if (s_IDT[i].ig.present) { 
+      Print("%d: segmentselector=%u, offset=%u, offsetLow=%u, segmentSelector=%u, reserved=%u, signature=%u, dpl=%u, present=%u, offsetHigh=%u\n",
+	    i,
+	    s_IDT[i].ig.segmentSelector,
+	    (s_IDT[i].ig.offsetHigh<<16) + s_IDT[i].ig.offsetLow,
+	    s_IDT[i].ig.offsetLow,
+	    s_IDT[i].ig.segmentSelector,
+	    s_IDT[i].ig.reserved,
+	    s_IDT[i].ig.signature,
+	    s_IDT[i].ig.dpl,
+	    s_IDT[i].ig.present,
+	    s_IDT[i].ig.offsetHigh);
+    }
+  }
+}
+
+
+void SerialDumpIDT()
+{
+  int i;
+  SerialPrint("IDT Contents:\n");
+
+  for (i=0;i<NUM_IDT_ENTRIES;i++) { 
+    if (s_IDT[i].ig.present) { 
+      SerialPrint("%d: segmentselector=%u, offset=%u, offsetLow=%u, segmentSelector=%u, reserved=%u, signature=%u, dpl=%u, present=%u, offsetHigh=%u\n",
+	    i,
+	    s_IDT[i].ig.segmentSelector,
+	    (s_IDT[i].ig.offsetHigh<<16) + s_IDT[i].ig.offsetLow,
+	    s_IDT[i].ig.offsetLow,
+	    s_IDT[i].ig.segmentSelector,
+	    s_IDT[i].ig.reserved,
+	    s_IDT[i].ig.signature,
+	    s_IDT[i].ig.dpl,
+	    s_IDT[i].ig.present,
+	    s_IDT[i].ig.offsetHigh);
+      SerialPrint("\n");
+    }
+  }
+}
+
+
+
+/* ----------------------------------------------------------------------
+ * Public functions
+ * ---------------------------------------------------------------------- */
+
+/*
+ * Initialize the Interrupt Descriptor Table.
+ * This will allow us to install C handler functions
+ * for interrupts, both processor-generated and
+ * those generated by external hardware.
+ */
+void Init_IDT(void)
+{
+    int i;
+    ushort_t limitAndBase[3];
+    ulong_t idtBaseAddr = (ulong_t) s_IDT;
+    ulong_t tableBaseAddr = (ulong_t) &g_entryPointTableStart;
+    ulong_t addr;
+
+    PrintBoth("Initializing IDT\n");
+
+    /* Make sure the layout of the entry point table is as we expect. */
+    KASSERT(g_handlerSizeNoErr == g_handlerSizeErr);
+    KASSERT((&g_entryPointTableEnd - &g_entryPointTableStart) ==
+	     g_handlerSizeNoErr * NUM_IDT_ENTRIES);
+
+    /*
+     * Build the IDT.
+     * We're taking advantage of the fact that all of the
+     * entry points are laid out consecutively, and that they
+     * are all padded to be the same size.
+     */
+    for (i = 0, addr = tableBaseAddr; i < NUM_IDT_ENTRIES; ++i) {
+	/*
+	 * All interrupts except for the syscall interrupt
+	 * must have kernel privilege to access.
+	 */
+	int dpl = (i == SYSCALL_INT) ? USER_PRIVILEGE : KERNEL_PRIVILEGE;
+	Init_Interrupt_Gate(&s_IDT[i], addr, dpl);
+	addr += g_handlerSizeNoErr;
+    }
+
+    /*
+     * Cruft together a 16 bit limit and 32 bit base address
+     * to load into the IDTR.
+     */
+    limitAndBase[0] = 8 * NUM_IDT_ENTRIES;
+    limitAndBase[1] = idtBaseAddr & 0xffff;
+    limitAndBase[2] = idtBaseAddr >> 16;
+
+    /* Install the new table in the IDTR. */
+    Load_IDTR(limitAndBase);
+}
+
+/*
+ * Initialize an interrupt gate with given handler address
+ * and descriptor privilege level.
+ */
+void Init_Interrupt_Gate(union IDT_Descriptor* desc, ulong_t addr,
+	int dpl)
+{
+    desc->ig.offsetLow = addr & 0xffff;
+    desc->ig.segmentSelector = KERNEL_CS;
+    desc->ig.reserved = 0;
+    desc->ig.signature = 0x70;  /* == 01110000b */
+    desc->ig.dpl = dpl;
+    desc->ig.present = 1;
+    desc->ig.offsetHigh = addr >> 16;
+}
+
+/*
+ * Install a C handler function for given interrupt.
+ * This is a lower-level notion than an "IRQ", which specifically
+ * means an interrupt triggered by external hardware.
+ * This function can install a handler for ANY interrupt.
+ */
+void Install_Interrupt_Handler(int interrupt, Interrupt_Handler handler)
+{
+    KASSERT(interrupt >= 0 && interrupt < NUM_IDT_ENTRIES);
+    g_interruptTable[interrupt] = handler;
+}