Initial creation of sourceware repositorygdb-4_18-branchpoint

1 files changed, 275 insertions, 0 deletions

diff --git a/sim/ppc/hw_vm.c b/sim/ppc/hw_vm.c
new file mode 100644
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+++ b/sim/ppc/hw_vm.c
@@ -0,0 +1,275 @@
+/*  This file is part of the program psim.
+    
+    Copyright (C) 1994-1996, Andrew Cagney <cagney@highland.com.au>
+    
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+    
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+    
+    You should have received a copy of the GNU General Public License
+    along with this program; if not, write to the Free Software
+    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+    
+    */
+
+
+#ifndef _HW_VM_C_
+#define _HW_VM_C_
+
+#include "device_table.h"
+#include "cpu.h"
+
+#include <signal.h>
+
+/* DEVICE
+
+   vm - virtual memory device for user simulation modes
+
+   DESCRIPTION
+
+   In user mode, mapped text, data and stack addresses are managed by
+   the core.  Unmapped addresses are passed onto this device (because
+   it establishes its self as the fallback device) for processing.
+
+   During initialization, children of this device will request the
+   mapping of the initial text and data segments.  Those requests are
+   passed onto the core device so that that may establish the initial
+   memory regions.
+
+   Once the simulation has started (as noted above) any access to an
+   unmapped address range will be passed down to this device as an IO
+   access.  This device will then either attach additional memory to
+   the core device or signal the access as being invalid.
+
+   The IOCTL function is used to notify this device of any changes to
+   the users `brk' point.
+
+   PROPERTIES
+
+   stack-base = <number>
+
+   Specifies the lower address of the stack segment in the users
+   virtual address space.  The initial stack page is defined by
+   stack-base + nr-bytes.
+
+   nr-bytes = <number>
+
+   Specifies the maximum size of the stack segment in the users
+   address space.
+
+   */
+
+typedef struct _hw_vm_device {
+  /* area of memory valid for stack addresses */
+  unsigned_word stack_base; /* min possible stack value */
+  unsigned_word stack_bound;
+  unsigned_word stack_lower_limit;
+  /* area of memory valid for heap addresses */
+  unsigned_word heap_base;
+  unsigned_word heap_bound;
+  unsigned_word heap_upper_limit;
+} hw_vm_device;
+
+
+static void
+hw_vm_init_address_callback(device *me)
+{
+  hw_vm_device *vm = (hw_vm_device*)device_data(me);
+
+  /* revert the stack/heap variables to their defaults */
+  vm->stack_base = device_find_integer_property(me, "stack-base");
+  vm->stack_bound = (vm->stack_base
+		     + device_find_integer_property(me, "nr-bytes"));
+  vm->stack_lower_limit = vm->stack_bound;
+  vm->heap_base = 0;
+  vm->heap_bound = 0;
+  vm->heap_upper_limit = 0;
+
+  /* establish this device as the default memory handler */
+  device_attach_address(device_parent(me),
+			attach_callback + 1,
+			0 /*address space - ignore*/,
+			0 /*addr - ignore*/,
+			(((unsigned)0)-1) /*nr_bytes - ignore*/,
+			access_read_write /*access*/,
+			me);
+}
+
+
+static void
+hw_vm_attach_address(device *me,
+		     attach_type attach,
+		     int space,
+		     unsigned_word addr,
+		     unsigned nr_bytes,
+		     access_type access,
+		     device *client) /*callback/default*/
+{
+  hw_vm_device *vm = (hw_vm_device*)device_data(me);
+  /* update end of bss if necessary */
+  if (vm->heap_base < addr + nr_bytes) {
+    vm->heap_base = addr + nr_bytes;
+    vm->heap_bound = addr + nr_bytes;
+    vm->heap_upper_limit = addr + nr_bytes;
+  }
+  device_attach_address(device_parent(me),
+			attach_raw_memory,
+			0 /*address space*/,
+			addr,
+			nr_bytes,
+			access,
+			me);
+}
+
+
+static unsigned
+hw_vm_add_space(device *me,
+		unsigned_word addr,
+		unsigned nr_bytes,
+		cpu *processor,
+		unsigned_word cia)
+{
+  hw_vm_device *vm = (hw_vm_device*)device_data(me);
+  unsigned_word block_addr;
+  unsigned block_nr_bytes;
+
+  /* an address in the stack area, allocate just down to the addressed
+     page */
+  if (addr >= vm->stack_base && addr < vm->stack_lower_limit) {
+    block_addr = FLOOR_PAGE(addr);
+    block_nr_bytes = vm->stack_lower_limit - block_addr;
+    vm->stack_lower_limit = block_addr;
+  }
+  /* an address in the heap area, allocate all of the required heap */
+  else if (addr >= vm->heap_upper_limit && addr < vm->heap_bound) {
+    block_addr = vm->heap_upper_limit;
+    block_nr_bytes = vm->heap_bound - vm->heap_upper_limit;
+    vm->heap_upper_limit = vm->heap_bound;
+  }
+  /* oops - an invalid address - abort the cpu */
+  else if (processor != NULL) {
+    cpu_halt(processor, cia, was_signalled, SIGSEGV);
+    return 0;
+  }
+  /* 2*oops - an invalid address and no processor */
+  else {
+    return 0;
+  }
+
+  /* got the parameters, allocate the space */
+  device_attach_address(device_parent(me),
+			attach_raw_memory,
+			0 /*address space*/,
+			block_addr,
+			block_nr_bytes,
+			access_read_write,
+			me);
+  return block_nr_bytes;
+}
+
+
+static unsigned
+hw_vm_io_read_buffer_callback(device *me,
+			   void *dest,
+			   int space,
+			   unsigned_word addr,
+			   unsigned nr_bytes,
+			   cpu *processor,
+			   unsigned_word cia)
+{
+  if (hw_vm_add_space(me, addr, nr_bytes, processor, cia) >= nr_bytes) {
+    memset(dest, 0, nr_bytes); /* always initialized to zero */
+    return nr_bytes;
+  }
+  else 
+    return 0;
+}
+
+
+static unsigned
+hw_vm_io_write_buffer_callback(device *me,
+			    const void *source,
+			    int space,
+			    unsigned_word addr,
+			    unsigned nr_bytes,
+			    cpu *processor,
+			    unsigned_word cia)
+{
+  if (hw_vm_add_space(me, addr, nr_bytes, processor, cia) >= nr_bytes) {
+    return device_dma_write_buffer(device_parent(me), source,
+				   space, addr,
+				   nr_bytes,
+				   0/*violate_read_only*/);
+  }
+  else
+    return 0;
+}
+
+
+static int
+hw_vm_ioctl(device *me,
+	    cpu *processor,
+	    unsigned_word cia,
+	    device_ioctl_request request,
+	    va_list ap)
+{
+  /* While the caller is notified that the heap has grown by the
+     requested amount, the heap is actually extended out to a page
+     boundary. */
+  hw_vm_device *vm = (hw_vm_device*)device_data(me);
+  switch (request) {
+  case device_ioctl_break:
+    {
+      unsigned_word requested_break = va_arg(ap, unsigned_word);
+      unsigned_word new_break = ALIGN_8(requested_break);
+      unsigned_word old_break = vm->heap_bound;
+      signed_word delta = new_break - old_break;
+      if (delta > 0)
+	vm->heap_bound = ALIGN_PAGE(new_break);
+      break;
+    }
+  default:
+    device_error(me, "Unsupported ioctl request");
+    break;
+  }
+  return 0;
+    
+}
+
+
+static device_callbacks const hw_vm_callbacks = {
+  { hw_vm_init_address_callback, },
+  { hw_vm_attach_address,
+    passthrough_device_address_detach, },
+  { hw_vm_io_read_buffer_callback,
+    hw_vm_io_write_buffer_callback, },
+  { NULL, passthrough_device_dma_write_buffer, },
+  { NULL, }, /* interrupt */
+  { generic_device_unit_decode,
+    generic_device_unit_encode, },
+  NULL, /* instance */
+  hw_vm_ioctl,
+};
+
+
+static void *
+hw_vm_create(const char *name,
+	     const device_unit *address,
+	     const char *args)
+{
+  hw_vm_device *vm = ZALLOC(hw_vm_device);
+  return vm;
+}
+
+const device_descriptor hw_vm_device_descriptor[] = {
+  { "vm", hw_vm_create, &hw_vm_callbacks },
+  { NULL },
+};
+
+#endif _HW_VM_C_