diff options
| -rw-r--r-- | Makefile | 8 | ||||
| -rw-r--r-- | data.S | 26 | ||||
| -rw-r--r-- | kernel.ld | 8 | ||||
| -rw-r--r-- | vm.c | 2 |
4 files changed, 13 insertions, 31 deletions
@@ -109,8 +109,8 @@ initcode: initcode.S $(OBJCOPY) -S -O binary initcode.out initcode $(OBJDUMP) -S initcode.o > initcode.asm -kernel: $(OBJS) entry.o data.o entryother initcode - $(LD) $(LDFLAGS) -T kernel.ld -e entry -o kernel entry.o data.o $(OBJS) -b binary initcode entryother +kernel: $(OBJS) entry.o entryother initcode + $(LD) $(LDFLAGS) -T kernel.ld -e entry -o kernel entry.o $(OBJS) -b binary initcode entryother $(OBJDUMP) -S kernel > kernel.asm $(OBJDUMP) -t kernel | sed '1,/SYMBOL TABLE/d; s/ .* / /; /^$$/d' > kernel.sym @@ -121,8 +121,8 @@ kernel: $(OBJS) entry.o data.o entryother initcode # great for testing the kernel on real hardware without # needing a scratch disk. MEMFSOBJS = $(filter-out ide.o,$(OBJS)) memide.o -kernelmemfs: $(MEMFSOBJS) entry.o data.o entryother initcode fs.img - $(LD) $(LDFLAGS) -Ttext 0x100000 -e main -o kernelmemfs entry.o data.o $(MEMFSOBJS) -b binary initcode entryother fs.img +kernelmemfs: $(MEMFSOBJS) entry.o entryother initcode fs.img + $(LD) $(LDFLAGS) -Ttext 0x100000 -e main -o kernelmemfs entry.o $(MEMFSOBJS) -b binary initcode entryother fs.img $(OBJDUMP) -S kernelmemfs > kernelmemfs.asm $(OBJDUMP) -t kernelmemfs | sed '1,/SYMBOL TABLE/d; s/ .* / /; /^$$/d' > kernelmemfs.sym @@ -1,26 +0,0 @@ -// The kernel layout is: -// -// text -// rodata -// data -// bss -// -// Conventionally, Unix linkers provide pseudo-symbols -// etext, edata, and end, at the end of the text, data, and bss. -// For the kernel mapping, we need the address at the beginning -// of the data section, but that's not one of the conventional -// symbols, because the convention started before there was a -// read-only rodata section between text and data. -// -// To get the address of the data section, we define a symbol -// named data and make sure this is the first object passed to -// the linker, so that it will be the first symbol in the data section. -// -// Alternative approaches would be to parse our own ELF header -// or to write a linker script, but this is simplest. - -.data -.align 4096 -.globl data -data: - .word 1 @@ -41,6 +41,14 @@ SECTIONS /* Adjust the address for the data segment to the next page */ . = ALIGN(0x1000); + /* Conventionally, Unix linkers provide pseudo-symbols + * etext, edata, and end, at the end of the text, data, and bss. + * For the kernel mapping, we need the address at the beginning + * of the data section, but that's not one of the conventional + * symbols, because the convention started before there was a + * read-only rodata section between text and data. */ + PROVIDE(data = .); + /* The data segment */ .data : { *(.data) @@ -7,7 +7,7 @@ #include "proc.h" #include "elf.h" -extern char data[]; // defined in data.S +extern char data[]; // defined by kernel.ld pde_t *kpgdir; // for use in scheduler() struct segdesc gdt[NSEGS]; |