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Diffstat (limited to 'sim/ppc/hw_vm.c')
| -rw-r--r-- | sim/ppc/hw_vm.c | 275 |
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 index 00000000000..e42b8002347 --- /dev/null +++ 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_ |