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+/* Copyright (C) 2004 The SOS Team
+ Copyright (C) 1999 Free Software Foundation, Inc.
+
+ 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.
+*/
+
+/* Include definitions of the multiboot standard */
+#include <bootstrap/multiboot.h>
+#include <hwcore/idt.h>
+#include <hwcore/gdt.h>
+#include <hwcore/irq.h>
+#include <hwcore/exception.h>
+#include <hwcore/i8254.h>
+#include <sos/list.h>
+#include <sos/physmem.h>
+#include <hwcore/paging.h>
+#include <sos/list.h>
+#include <sos/klibc.h>
+#include <sos/assert.h>
+#include <drivers/x86_videomem.h>
+#include <drivers/bochs.h>
+
+
+/* Helper function to display each bits of a 32bits integer on the
+ screen as dark or light carrets */
+static void display_bits(unsigned char row, unsigned char col,
+ unsigned char attribute,
+ sos_ui32_t integer)
+{
+ int i;
+ /* Scan each bit of the integer, MSb first */
+ for (i = 31 ; i >= 0 ; i--)
+ {
+ /* Test if bit i of 'integer' is set */
+ int bit_i = (integer & (1 << i));
+ /* Ascii 219 => dark carret, Ascii 177 => light carret */
+ unsigned char ascii_code = bit_i?219:177;
+ sos_x86_videomem_putchar(row, col++,
+ attribute,
+ ascii_code);
+ }
+}
+
+
+/* Clock IRQ handler */
+static void clk_it(int intid)
+{
+ static sos_ui32_t clock_count = 0;
+
+ display_bits(0, 48,
+ SOS_X86_VIDEO_FG_LTGREEN | SOS_X86_VIDEO_BG_BLUE,
+ clock_count);
+ clock_count++;
+
+}
+
+/* Page fault exception handler */
+static void pgflt_ex(int exid)
+{
+ sos_bochs_printf("Got page fault\n");
+ sos_x86_videomem_printf(10, 30,
+ SOS_X86_VIDEO_FG_LTRED | SOS_X86_VIDEO_BG_BLUE,
+ "Got EXPECTED (?) Page fault ! But where ???");
+ for (;;) ;
+}
+
+static void test_paging(sos_vaddr_t sos_kernel_core_top_vaddr)
+{
+ /* The (linear) address of the page holding the code we are
+ currently executing */
+ sos_vaddr_t vpage_code = SOS_PAGE_ALIGN_INF(test_paging);
+
+ /* The new physical page that will hold the code */
+ sos_paddr_t ppage_new;
+
+ /* Where this page will be mapped temporarily in order to copy the
+ code into it: right after the kernel code/data */
+ sos_vaddr_t vpage_tmp = sos_kernel_core_top_vaddr;
+
+ unsigned i;
+
+ /* Bind the page fault exception to one of our routines */
+ sos_exception_set_routine(SOS_EXCEPT_PAGE_FAULT,
+ pgflt_ex);
+
+ /*
+ * Test 1: move the page where we execute the code elsewhere in
+ * physical memory
+ */
+ sos_x86_videomem_printf(4, 0,
+ SOS_X86_VIDEO_FG_LTGREEN | SOS_X86_VIDEO_BG_BLUE,
+ "Moving current code elsewhere in physical memory:");
+
+
+ /* Allocate a new physical page */
+ ppage_new = sos_physmem_ref_physpage_new(FALSE);
+ if (! ppage_new)
+ {
+ /* STOP ! No memory left */
+ sos_x86_videomem_putstring(20, 0,
+ SOS_X86_VIDEO_FG_LTRED
+ | SOS_X86_VIDEO_BG_BLUE,
+ "test_paging : Cannot allocate page");
+ return;
+ }
+
+ sos_x86_videomem_printf(5, 0,
+ SOS_X86_VIDEO_FG_YELLOW | SOS_X86_VIDEO_BG_BLUE,
+ "Hello from the address 0x%x in physical memory",
+ sos_paging_get_paddr(vpage_code));
+
+ sos_x86_videomem_printf(6, 0,
+ SOS_X86_VIDEO_FG_YELLOW | SOS_X86_VIDEO_BG_BLUE,
+ "Transfer vpage 0x%x: ppage 0x%x -> 0x%x (tmp vpage 0x%x)",
+ vpage_code,
+ sos_paging_get_paddr(vpage_code),
+ ppage_new,
+ (unsigned)vpage_tmp);
+
+ /* Map the page somewhere (right after the kernel mapping) in order
+ to copy the code we are currently executing */
+ sos_paging_map(ppage_new, vpage_tmp,
+ FALSE,
+ SOS_VM_MAP_ATOMIC
+ | SOS_VM_MAP_PROT_READ
+ | SOS_VM_MAP_PROT_WRITE);
+
+ /* Ok, the new page is referenced by the mapping, we can release our
+ reference to it */
+ sos_physmem_unref_physpage(ppage_new);
+
+ /* Copy the contents of the current page of code to this new page
+ mapping */
+ memcpy((void*)vpage_tmp,
+ (void*)vpage_code,
+ SOS_PAGE_SIZE);
+
+ /* Transfer the mapping of the current page of code to this new page */
+ sos_paging_map(ppage_new, vpage_code,
+ FALSE,
+ SOS_VM_MAP_ATOMIC
+ | SOS_VM_MAP_PROT_READ
+ | SOS_VM_MAP_PROT_WRITE);
+
+ /* Ok, here we are: we have changed the physcal page that holds the
+ code we are executing ;). However, this new page is mapped at 2
+ virtual addresses:
+ - vpage_tmp
+ - vpage_code
+ We can safely unmap it from sos_kernel_core_top_vaddr, while
+ still keeping the vpage_code mapping */
+ sos_paging_unmap(vpage_tmp);
+
+ sos_x86_videomem_printf(7, 0,
+ SOS_X86_VIDEO_FG_YELLOW | SOS_X86_VIDEO_BG_BLUE,
+ "Hello from the address 0x%x in physical memory",
+ sos_paging_get_paddr(vpage_code));
+
+ sos_x86_videomem_printf(9, 0,
+ SOS_X86_VIDEO_FG_LTGREEN | SOS_X86_VIDEO_BG_BLUE,
+ "Provoking a page fault:");
+
+ /*
+ * Test 2: make sure the #PF handler works
+ */
+
+ /* Scan part of the kernel up to a page fault. This page fault
+ should occur on the first page unmapped after the kernel area,
+ which is exactly the page we temporarily mapped/unmapped
+ (vpage_tmp) above to move the kernel code we are executing */
+ for (i = vpage_code ; /* none */ ; i += SOS_PAGE_SIZE)
+ {
+ unsigned *pint = (unsigned *)SOS_PAGE_ALIGN_INF(i);
+ sos_bochs_printf("Test vaddr 0x%x : val=", (unsigned)pint);
+ sos_x86_videomem_printf(10, 0,
+ SOS_X86_VIDEO_FG_YELLOW | SOS_X86_VIDEO_BG_BLUE,
+ "Test vaddr 0x%x : val= ",
+ (unsigned)pint);
+ sos_bochs_printf("0x%x\n", *pint);
+ sos_x86_videomem_printf(10, 30,
+ SOS_X86_VIDEO_FG_YELLOW | SOS_X86_VIDEO_BG_BLUE,
+ "0x%x ", *pint);
+ }
+
+ /* BAD ! Did not get the page fault... */
+ sos_x86_videomem_printf(20, 0,
+ SOS_X86_VIDEO_FG_LTRED | SOS_X86_VIDEO_BG_BLUE,
+ "We should have had a #PF at vaddr 0x%x !",
+ vpage_tmp);
+}
+
+/* The C entry point of our operating system */
+void sos_main(unsigned long magic, unsigned long addr)
+{
+ unsigned i;
+ sos_paddr_t sos_kernel_core_base_paddr, sos_kernel_core_top_paddr;
+
+ /* Grub sends us a structure, called multiboot_info_t with a lot of
+ precious informations about the system, see the multiboot
+ documentation for more information. */
+ multiboot_info_t *mbi;
+ mbi = (multiboot_info_t *) addr;
+
+ /* Setup bochs and console, and clear the console */
+ sos_bochs_setup();
+
+ sos_x86_videomem_setup();
+ sos_x86_videomem_cls(SOS_X86_VIDEO_BG_BLUE);
+
+ /* Greetings from SOS */
+ if (magic == MULTIBOOT_BOOTLOADER_MAGIC)
+ /* Loaded with Grub */
+ sos_x86_videomem_printf(1, 0,
+ SOS_X86_VIDEO_FG_YELLOW | SOS_X86_VIDEO_BG_BLUE,
+ "Welcome From GRUB to %s%c RAM is %dMB (upper mem = 0x%x kB)",
+ "SOS", ',',
+ (unsigned)(mbi->mem_upper >> 10) + 1,
+ (unsigned)mbi->mem_upper);
+ else
+ /* Not loaded with grub */
+ sos_x86_videomem_printf(1, 0,
+ SOS_X86_VIDEO_FG_YELLOW | SOS_X86_VIDEO_BG_BLUE,
+ "Welcome to SOS");
+
+ sos_bochs_putstring("Message in a bochs\n");
+
+ /* Setup CPU segmentation and IRQ subsystem */
+ sos_gdt_setup();
+ sos_idt_setup();
+
+ /* Setup SOS IRQs and exceptions subsystem */
+ sos_exceptions_setup();
+ sos_irq_setup();
+
+ /* Configure the timer so as to raise the IRQ0 at a 100Hz rate */
+ sos_i8254_set_frequency(100);
+
+
+ /* We need a multiboot-compliant boot loader to get the size of the RAM */
+ if (magic != MULTIBOOT_BOOTLOADER_MAGIC)
+ {
+ sos_x86_videomem_putstring(20, 0,
+ SOS_X86_VIDEO_FG_LTRED
+ | SOS_X86_VIDEO_BG_BLUE
+ | SOS_X86_VIDEO_FG_BLINKING,
+ "I'm not loaded with Grub !");
+ /* STOP ! */
+ for (;;)
+ continue;
+ }
+
+ /* Binding some HW interrupts and exceptions to software routines */
+ sos_irq_set_routine(SOS_IRQ_TIMER,
+ clk_it);
+ /* Enabling the HW interrupts here, this will make the timer HW
+ interrupt call our clk_it handler */
+ asm volatile ("sti\n");
+ /* Multiboot says: "The value returned for upper memory is maximally
+ the address of the first upper memory hole minus 1 megabyte.". It
+ also adds: "It is not guaranteed to be this value." aka "YMMV" ;) */
+ sos_physmem_setup((mbi->mem_upper<<10) + (1<<20),
+ & sos_kernel_core_base_paddr,
+ & sos_kernel_core_top_paddr);
+
+ /*
+ * Switch to paged-memory mode
+ */
+
+ /* Disabling interrupts should seem more correct, but it's not really
+ necessary at this stage */
+ if (sos_paging_setup(sos_kernel_core_base_paddr,
+ sos_kernel_core_top_paddr))
+ sos_bochs_printf("Could not setup paged memory mode\n");
+ sos_x86_videomem_printf(2, 0,
+ SOS_X86_VIDEO_FG_YELLOW | SOS_X86_VIDEO_BG_BLUE,
+ "Paged-memory mode is activated");
+
+ test_paging(sos_kernel_core_top_paddr);
+
+ /* An operatig system never ends */
+ for (;;)
+ continue;
+
+ return;
+}
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