Map kernel high

Very important to give qemu memory through PHYSTOP :(

Makefile

@@ -109,7 +109,7 @@ initcode: initcode.S
 	$(OBJDUMP) -S initcode.o > initcode.asm
 
 kernel: $(OBJS) multiboot.o data.o bootother initcode
-	$(LD) $(LDFLAGS) -Ttext 0x100000 -e main -o kernel multiboot.o data.o $(OBJS) -b binary initcode bootother
+	$(LD) $(LDFLAGS) -T kernel.ld -e multiboot_entry -o kernel multiboot.o data.o $(OBJS) -b binary initcode bootother
 	$(OBJDUMP) -S kernel > kernel.asm
 	$(OBJDUMP) -t kernel | sed '1,/SYMBOL TABLE/d; s/ .* / /; /^$$/d' > kernel.sym
 
@@ -200,7 +200,7 @@ QEMUGDB = $(shell if $(QEMU) -help | grep -q '^-gdb'; \
 ifndef CPUS
 CPUS := 2
 endif
-QEMUOPTS = -hdb fs.img xv6.img -smp $(CPUS)
+QEMUOPTS = -hdb fs.img xv6.img -smp $(CPUS) -m 512
 
 qemu: fs.img xv6.img
 	$(QEMU) -serial mon:stdio $(QEMUOPTS)

bootmain.c

@@ -8,6 +8,7 @@
 #include "types.h"
 #include "elf.h"
 #include "x86.h"
+#include "memlayout.h"
 
 #define SECTSIZE  512
 
@@ -19,7 +20,7 @@ bootmain(void)
   struct elfhdr *elf;
   struct proghdr *ph, *eph;
   void (*entry)(void);
-  uchar* va;
+  uchar* pa;
 
   elf = (struct elfhdr*)0x10000;  // scratch space
 
@@ -34,15 +35,15 @@ bootmain(void)
   ph = (struct proghdr*)((uchar*)elf + elf->phoff);
   eph = ph + elf->phnum;
   for(; ph < eph; ph++){
-    va = (uchar*)ph->va;
-    readseg(va, ph->filesz, ph->offset);
+    pa = (uchar*)ph->pa;
+    readseg(pa, ph->filesz, ph->offset);
     if(ph->memsz > ph->filesz)
-      stosb(va + ph->filesz, 0, ph->memsz - ph->filesz);
+      stosb(pa + ph->filesz, 0, ph->memsz - ph->filesz);
   }
 
   // Call the entry point from the ELF header.
   // Does not return!
-  entry = (void(*)(void))(elf->entry);
+  entry = (void(*)(void))(elf->entry & 0xFFFFFF);
   entry();
 }
 

bootother.S

@@ -1,4 +1,5 @@
 #include "asm.h"
+#include "memlayout.h"
 
 # Each non-boot CPU ("AP") is started up in response to a STARTUP
 # IPI from the boot CPU.  Section B.4.2 of the Multi-Processor
@@ -24,6 +25,8 @@
 
 #define CR0_PE    1
 
+#define RELOC1(x) ((x) + KERNBASE)    // same as V2P, but without casts
+
 .code16           
 .globl start
 start:
@@ -40,7 +43,7 @@ start:
   movl    %eax, %cr0
 
 //PAGEBREAK!
-  ljmp    $(SEG_KCODE<<3), $start32
+  ljmpl    $(SEG_KCODE<<3), $(start32+KERNBASE)
 
 .code32
 start32:
@@ -53,10 +56,10 @@ start32:
   movw    %ax, %gs
 
   # switch to the stack allocated by bootothers()
-  movl    start-4, %esp
+  movl    RELOC1(start-4), %esp
 
   # call mpmain()
-  call	*(start-8)
+  call	*(RELOC1(start)-8)
 
   movw    $0x8a00, %ax
   movw    %ax, %dx
@@ -69,8 +72,9 @@ spin:
 .p2align 2
 gdt:
   SEG_NULLASM
-  SEG_ASM(STA_X|STA_R, 0x0, 0xffffffff)
-  SEG_ASM(STA_W, 0x0, 0xffffffff)
+  SEG_ASM(STA_X|STA_R, -KERNBASE, 0xffffffff)
+  SEG_ASM(STA_W, -KERNBASE, 0xffffffff)
+
 
 gdtdesc:
   .word   (gdtdesc - gdt - 1)

console.c

@@ -9,6 +9,7 @@
 #include "spinlock.h"
 #include "fs.h"
 #include "file.h"
+#include "memlayout.h"
 #include "mmu.h"
 #include "proc.h"
 #include "x86.h"
@@ -60,6 +61,9 @@ cprintf(char *fmt, ...)
   if(locking)
     acquire(&cons.lock);
 
+  if (fmt == 0)
+    panic("null fmt");
+
   argp = (uint*)(void*)(&fmt + 1);
   state = 0;
   for(i = 0; (c = fmt[i] & 0xff) != 0; i++){
@@ -121,7 +125,7 @@ panic(char *s)
 //PAGEBREAK: 50
 #define BACKSPACE 0x100
 #define CRTPORT 0x3d4
-static ushort *crt = (ushort*)0xb8000;  // CGA memory
+static ushort *crt = (ushort*)P2V(0xb8000);  // CGA memory
 
 static void
 cgaputc(int c)

defs.h

@@ -62,6 +62,7 @@ extern uchar    ioapicid;
 void            ioapicinit(void);
 
 // kalloc.c
+char*           pgalloc(void);
 char*           kalloc(void);
 void            kfree(char*);
 void            kinit(void);
@@ -160,6 +161,7 @@ void            uartintr(void);
 void            uartputc(int);
 
 // vm.c
+void            pginit(char* (*alloc)());
 void            seginit(void);
 void            kvmalloc(void);
 void            vmenable(void);

exec.c

@@ -1,5 +1,6 @@
 #include "types.h"
 #include "param.h"
+#include "memlayout.h"
 #include "mmu.h"
 #include "proc.h"
 #include "defs.h"

ide.c

@@ -3,6 +3,7 @@
 #include "types.h"
 #include "defs.h"
 #include "param.h"
+#include "memlayout.h"
 #include "mmu.h"
 #include "proc.h"
 #include "x86.h"

kalloc.c

@@ -5,6 +5,7 @@
 #include "types.h"
 #include "defs.h"
 #include "param.h"
+#include "memlayout.h"
 #include "mmu.h"
 #include "spinlock.h"
 
@@ -18,6 +19,20 @@ struct {
 } kmem;
 
 extern char end[]; // first address after kernel loaded from ELF file
+char *newend;
+
+// simple page allocator to get off the ground during boot
+char *
+pgalloc(void)
+{
+  if (newend == 0)
+    newend = end;
+
+  void *p = (void*)PGROUNDUP((uint)newend);
+  memset(p, 0, PGSIZE);
+  newend = newend + PGSIZE;
+  return p;
+}
 
 // Initialize free list of physical pages.
 void
@@ -26,8 +41,8 @@ kinit(void)
   char *p;
 
   initlock(&kmem.lock, "kmem");
-  p = (char*)PGROUNDUP((uint)end);
-  for(; p + PGSIZE <= (char*)PHYSTOP; p += PGSIZE)
+  p = (char*)PGROUNDUP((uint)newend);
+  for(; p + PGSIZE <= (char*)p2v(PHYSTOP); p += PGSIZE)
     kfree(p);
 }
 
@@ -41,7 +56,7 @@ kfree(char *v)
 {
   struct run *r;
 
-  if((uint)v % PGSIZE || v < end || (uint)v >= PHYSTOP) 
+  if((uint)v % PGSIZE || v < end || v2p(v) >= PHYSTOP) 
     panic("kfree");
 
   // Fill with junk to catch dangling refs.
@@ -67,6 +82,7 @@ kalloc(void)
   if(r)
     kmem.freelist = r->next;
   release(&kmem.lock);
+  cprintf("kalloc: 0x%x\n", r);
   return (char*)r;
 }
 

main.c

@@ -1,6 +1,7 @@
 #include "types.h"
 #include "defs.h"
 #include "param.h"
+#include "memlayout.h"
 #include "mmu.h"
 #include "proc.h"
 #include "x86.h"
@@ -9,13 +10,16 @@ static void bootothers(void);
 static void mpmain(void);
 void jmpkstack(void)  __attribute__((noreturn));
 void mainc(void);
+static volatile int newpgdir;
+
 
 // Bootstrap processor starts running C code here.
 // Allocate a real stack and switch to it, first
 // doing some setup required for memory allocator to work.
 int
 main(void)
 {
+  pginit(pgalloc);
   mpinit();        // collect info about this machine
   lapicinit(mpbcpu());
   seginit();       // set up segments
@@ -46,7 +50,6 @@ mainc(void)
   ioapicinit();    // another interrupt controller
   consoleinit();   // I/O devices & their interrupts
   uartinit();      // serial port
-  kvmalloc();      // initialize the kernel page table
   pinit();         // process table
   tvinit();        // trap vectors
   binit();         // buffer cache
@@ -57,7 +60,8 @@ mainc(void)
     timerinit();   // uniprocessor timer
   userinit();      // first user process
   bootothers();    // start other processors
-
+  kvmalloc();      // new kernel page table wo. bottom mapped
+  newpgdir = 1;
   // Finish setting up this processor in mpmain.
   mpmain();
 }
@@ -66,16 +70,25 @@ mainc(void)
 // Bootstrap CPU comes here from mainc().
 // Other CPUs jump here from bootother.S.
 static void
-mpmain(void)
+mpboot(void)
 {
-  if(cpunum() != mpbcpu()){
-    seginit();
-    lapicinit(cpunum());
-  }
   vmenable();        // turn on paging
+  seginit();
+  lapicinit(cpunum());
+  mpmain();
+}
+
+// Common CPU setup code.
+// Bootstrap CPU comes here from mainc().
+// Other CPUs jump here from bootother.S.
+static void
+mpmain(void)
+{
   cprintf("cpu%d: starting\n", cpu->id);
   idtinit();       // load idt register
   xchg(&cpu->booted, 1); // tell bootothers() we're up
+  while (!newpgdir) ;  // wait until we have new page dir
+  switchkvm();     // switch to new page dir
   scheduler();     // start running processes
 }
 
@@ -91,7 +104,7 @@ bootothers(void)
   // Write bootstrap code to unused memory at 0x7000.
   // The linker has placed the image of bootother.S in
   // _binary_bootother_start.
-  code = (uchar*)0x7000;
+  code = p2v(0x7000);
   memmove(code, _binary_bootother_start, (uint)_binary_bootother_size);
 
   for(c = cpus; c < cpus+ncpu; c++){
@@ -103,9 +116,9 @@ bootothers(void)
     // its first instruction.
     stack = kalloc();
     *(void**)(code-4) = stack + KSTACKSIZE;
-    *(void**)(code-8) = mpmain;
+    *(void**)(code-8) = mpboot;
 
-    lapicstartap(c->id, (uint)code);
+    lapicstartap(c->id, v2p(code));
 
     // Wait for cpu to finish mpmain()
     while(c->booted == 0)

mmu.h

@@ -106,18 +106,10 @@ struct segdesc {
 // construct linear address from indexes and offset
 #define PGADDR(d, t, o)	((uint)((d) << PDXSHIFT | (t) << PTXSHIFT | (o)))
 
-// turn a kernel linear address into a physical address.
-// all of the kernel data structures have linear and
-// physical addresses that are equal.
-#define PADDR(a)       ((uint)(a))
-
 // Page directory and page table constants.
 #define NPDENTRIES	1024		// page directory entries per page directory
 #define NPTENTRIES	1024		// page table entries per page table
 
-#define PGSIZE		4096		// bytes mapped by a page
-#define PGSHIFT		12		// log2(PGSIZE)
-
 #define PTXSHIFT	12		// offset of PTX in a linear address
 #define PDXSHIFT	22		// offset of PDX in a linear address
 

mp.c

@@ -5,6 +5,7 @@
 #include "types.h"
 #include "defs.h"
 #include "param.h"
+#include "memlayout.h"
 #include "mp.h"
 #include "x86.h"
 #include "mmu.h"
@@ -39,6 +40,7 @@ mpsearch1(uchar *addr, int len)
 {
   uchar *e, *p;
 
+  addr = p2v((uint) addr);
   e = addr+len;
   for(p = addr; p < e; p += sizeof(struct mp))
     if(memcmp(p, "_MP_", 4) == 0 && sum(p, sizeof(struct mp)) == 0)
@@ -83,7 +85,7 @@ mpconfig(struct mp **pmp)
 
   if((mp = mpsearch()) == 0 || mp->physaddr == 0)
     return 0;
-  conf = (struct mpconf*)mp->physaddr;
+  conf = (struct mpconf*) p2v((uint) mp->physaddr);
   if(memcmp(conf, "PCMP", 4) != 0)
     return 0;
   if(conf->version != 1 && conf->version != 4)

multiboot.S

@@ -15,6 +15,9 @@
 # }
 
 #include "asm.h"
+#include "memlayout.h"
+
+#define RELOC(x) ((x) - KERNBASE)    // same as V2P, but without casts
 
 #define STACK 4096
 
@@ -42,7 +45,7 @@ multiboot_header:
 # boot loader - bootasm.S - sets up.
 .globl multiboot_entry
 multiboot_entry:
-  lgdt gdtdesc
+  lgdt RELOC(gdtdesc)
   ljmp $(SEG_KCODE<<3), $mbstart32
 
 mbstart32:
@@ -65,11 +68,11 @@ spin:
 .p2align 2                                # force 4 byte alignment
 gdt:
   SEG_NULLASM                             # null seg
-  SEG_ASM(STA_X|STA_R, 0x0, 0xffffffff)   # code seg
-  SEG_ASM(STA_W, 0x0, 0xffffffff)         # data seg
+  SEG_ASM(STA_X|STA_R, -KERNBASE, 0xffffffff)   # code seg
+  SEG_ASM(STA_W, -KERNBASE, 0xffffffff)         # data seg
 
 gdtdesc:
   .word   (gdtdesc - gdt - 1)             # sizeof(gdt) - 1
-  .long   gdt                             # address gdt
+  .long   RELOC(gdt)                      # address gdt
 
 .comm stack, STACK