diff options
| -rw-r--r-- | Makefile | 10 | ||||
| -rw-r--r-- | main.c | 4 | ||||
| -rw-r--r-- | proc.c | 3 | ||||
| -rw-r--r-- | proc.h | 17 |
4 files changed, 16 insertions, 18 deletions
@@ -37,7 +37,7 @@ AS = $(TOOLPREFIX)gas LD = $(TOOLPREFIX)ld OBJCOPY = $(TOOLPREFIX)objcopy OBJDUMP = $(TOOLPREFIX)objdump -CFLAGS = -fno-builtin -fno-strict-aliasing -O2 -Wall -MD -ggdb -m32 +CFLAGS = -fno-pic -static -fno-builtin -fno-strict-aliasing -O2 -Wall -MD -ggdb -m32 CFLAGS += $(shell $(CC) -fno-stack-protector -E -x c /dev/null >/dev/null 2>&1 && echo -fno-stack-protector) ASFLAGS = -m32 # FreeBSD ld wants ``elf_i386_fbsd'' @@ -49,8 +49,8 @@ xv6.img: bootblock kernel fs.img dd if=kernel of=xv6.img seek=1 conv=notrunc bootblock: bootasm.S bootmain.c - $(CC) $(CFLAGS) -O -nostdinc -I. -c bootmain.c - $(CC) $(CFLAGS) -nostdinc -I. -c bootasm.S + $(CC) $(CFLAGS) -fno-pic -O -nostdinc -I. -c bootmain.c + $(CC) $(CFLAGS) -fno-pic -nostdinc -I. -c bootasm.S $(LD) $(LDFLAGS) -N -e start -Ttext 0x7C00 -o bootblock.o bootasm.o bootmain.o $(OBJDUMP) -S bootblock.o > bootblock.asm $(OBJCOPY) -S -O binary -j .text bootblock.o bootblock @@ -93,7 +93,7 @@ _forktest: forktest.o $(ULIB) $(OBJDUMP) -S _forktest > forktest.asm mkfs: mkfs.c fs.h - gcc $(CFLAGS) -Wall -o mkfs mkfs.c + gcc -Wall -o mkfs mkfs.c UPROGS=\ _cat\ @@ -139,7 +139,7 @@ bochs : fs.img xv6.img bochs -q qemu: fs.img xv6.img - qemu -parallel stdio -hdb fs.img xv6.img + qemu -parallel stdio -smp 2 -hdb fs.img xv6.img qemutty: fs.img xv6.img qemu -nographic -smp 2 -hdb fs.img xv6.img @@ -5,9 +5,6 @@ #include "proc.h" #include "x86.h" -__thread struct cpu *cpu; -__thread struct proc *proc; - static void bootothers(void); static void mpmain(void) __attribute__((noreturn)); @@ -22,6 +19,7 @@ main(void) ioapicinit(); // another interrupt controller consoleinit(); // I/O devices & their interrupts uartinit(); // serial port +cprintf("cpus %p cpu %p\n", cpus, cpu); cprintf("\ncpu%d: starting xv6\n\n", cpu->id); kinit(); // physical memory allocator @@ -70,12 +70,11 @@ ksegment(void) c = &cpus[cpunum()]; c->gdt[SEG_KCODE] = SEG(STA_X|STA_R, 0, 0x100000 + 64*1024-1, 0); c->gdt[SEG_KDATA] = SEG(STA_W, 0, 0xffffffff, 0); - c->gdt[SEG_KCPU] = SEG(STA_W, &c->tlsstruct, 0xffffffff, 0); + c->gdt[SEG_KCPU] = SEG(STA_W, &c->cpu, 8, 0); lgdt(c->gdt, sizeof(c->gdt)); loadfsgs(SEG_KCPU << 3); // Initialize cpu-local storage. - c->tlsstruct = &c->tlsstruct; asm volatile(""); // Do not let gcc reorder across this line. cpu = c; proc = 0; @@ -59,10 +59,9 @@ struct cpu { int ncli; // Depth of pushcli nesting. int intena; // Were interrupts enabled before pushcli? - // "Thread"-local storage variables + // Cpu-local storage variables; see below struct cpu *cpu; struct proc *proc; - void *tlsstruct; }; extern struct cpu cpus[NCPU]; @@ -70,9 +69,11 @@ extern int ncpu; // Per-CPU variables, holding pointers to the // current cpu and to the current process. -// The __thread prefix tells gcc to refer to them in the segment -// pointed at by gs; the name __thread derives from the use -// of the same mechanism to provide per-thread storage in -// multithreaded user programs. -extern __thread struct cpu *cpu; // This cpu. -extern __thread struct proc *proc; // Current process on this cpu. +// The asm suffix tells gcc to use "%gs:0" to refer to cpu +// and "%gs:4" to refer to proc. ksegment sets up the +// %gs segment register so that %gs refers to the memory +// holding those two variables in the local cpu's struct cpu. +// This is similar to how thread-local variables are implemented +// in thread libraries such as Linux pthreads. +extern struct cpu *cpu asm("%gs:0"); // This cpu. +extern struct proc *proc asm("%gs:4"); // Current proc on this cpu. |