process.c

microwindows移植到S3C44B0的源码

	if (t->flags & SPARC_FLAG_PERFCTR) {
		t->user_cntd0 = t->user_cntd1 = NULL;
		t->pcr_reg = 0;
		t->flags &= ~(SPARC_FLAG_PERFCTR);
		write_pcr(0);
	}
}

void flush_thread(void)
{
	struct thread_struct *t = &current->thread;

	if (t->flags & SPARC_FLAG_ABI_PENDING)
		t->flags ^= (SPARC_FLAG_ABI_PENDING |
			     SPARC_FLAG_32BIT);
	if (current->mm) {
		unsigned long pgd_cache = 0UL;

		if (t->flags & SPARC_FLAG_32BIT) {
			struct mm_struct *mm = current->mm;
			pgd_t *pgd0 = &mm->pgd[0];

			if (pgd_none(*pgd0)) {
				pmd_t *page = pmd_alloc_one_fast(NULL, 0);
				if (!page)
					page = pmd_alloc_one(NULL, 0);
				pgd_set(pgd0, page);
			}
			pgd_cache = pgd_val(*pgd0) << 11UL;
		}
		__asm__ __volatile__("stxa %0, [%1] %2\n\t"
				     "membar #Sync"
				     : /* no outputs */
				     : "r" (pgd_cache),
				     "r" (TSB_REG),
				     "i" (ASI_DMMU));
	}
	t->w_saved = 0;

	/* Turn off performance counters if on. */
	if (t->flags & SPARC_FLAG_PERFCTR) {
		t->user_cntd0 = t->user_cntd1 = NULL;
		t->pcr_reg = 0;
		t->flags &= ~(SPARC_FLAG_PERFCTR);
		write_pcr(0);
	}

	/* Clear FPU register state. */
	t->fpsaved[0] = 0;
	
	if (t->current_ds.seg != ASI_AIUS)
		set_fs(USER_DS);

	/* Init new signal delivery disposition. */
	t->flags &= ~SPARC_FLAG_NEWSIGNALS;
}

/* It's a bit more tricky when 64-bit tasks are involved... */
static unsigned long clone_stackframe(unsigned long csp, unsigned long psp)
{
	unsigned long fp, distance, rval;

	if (!(current->thread.flags & SPARC_FLAG_32BIT)) {
		csp += STACK_BIAS;
		psp += STACK_BIAS;
		__get_user(fp, &(((struct reg_window *)psp)->ins[6]));
		fp += STACK_BIAS;
	} else
		__get_user(fp, &(((struct reg_window32 *)psp)->ins[6]));

	/* Now 8-byte align the stack as this is mandatory in the
	 * Sparc ABI due to how register windows work.  This hides
	 * the restriction from thread libraries etc.  -DaveM
	 */
	csp &= ~7UL;

	distance = fp - psp;
	rval = (csp - distance);
	if (copy_in_user(rval, psp, distance))
		rval = 0;
	else if (current->thread.flags & SPARC_FLAG_32BIT) {
		if (put_user(((u32)csp), &(((struct reg_window32 *)rval)->ins[6])))
			rval = 0;
	} else {
		if (put_user(((u64)csp - STACK_BIAS),
			     &(((struct reg_window *)rval)->ins[6])))
			rval = 0;
		else
			rval = rval - STACK_BIAS;
	}

	return rval;
}

/* Standard stuff. */
static inline void shift_window_buffer(int first_win, int last_win,
				       struct thread_struct *t)
{
	int i;

	for (i = first_win; i < last_win; i++) {
		t->rwbuf_stkptrs[i] = t->rwbuf_stkptrs[i+1];
		memcpy(&t->reg_window[i], &t->reg_window[i+1],
		       sizeof(struct reg_window));
	}
}

void synchronize_user_stack(void)
{
	struct thread_struct *t = &current->thread;
	unsigned long window;

	flush_user_windows();
	if ((window = t->w_saved) != 0) {
		int winsize = REGWIN_SZ;
		int bias = 0;

		if (t->flags & SPARC_FLAG_32BIT)
			winsize = REGWIN32_SZ;
		else
			bias = STACK_BIAS;

		window -= 1;
		do {
			unsigned long sp = (t->rwbuf_stkptrs[window] + bias);
			struct reg_window *rwin = &t->reg_window[window];

			if (!copy_to_user((char *)sp, rwin, winsize)) {
				shift_window_buffer(window, t->w_saved - 1, t);
				t->w_saved--;
			}
		} while (window--);
	}
}

void fault_in_user_windows(void)
{
	struct thread_struct *t = &current->thread;
	unsigned long window;
	int winsize = REGWIN_SZ;
	int bias = 0;

	if (t->flags & SPARC_FLAG_32BIT)
		winsize = REGWIN32_SZ;
	else
		bias = STACK_BIAS;

	flush_user_windows();
	window = t->w_saved;

	if (window != 0) {
		window -= 1;
		do {
			unsigned long sp = (t->rwbuf_stkptrs[window] + bias);
			struct reg_window *rwin = &t->reg_window[window];

			if (copy_to_user((char *)sp, rwin, winsize))
				goto barf;
		} while (window--);
	}
	t->w_saved = 0;
	return;

barf:
	t->w_saved = window + 1;
	do_exit(SIGILL);
}

/* Copy a Sparc thread.  The fork() return value conventions
 * under SunOS are nothing short of bletcherous:
 * Parent -->  %o0 == childs  pid, %o1 == 0
 * Child  -->  %o0 == parents pid, %o1 == 1
 */
int copy_thread(int nr, unsigned long clone_flags, unsigned long sp,
		unsigned long unused,
		struct task_struct *p, struct pt_regs *regs)
{
	struct thread_struct *t = &p->thread;
	char *child_trap_frame;

#ifdef CONFIG_DEBUG_SPINLOCK
	t->smp_lock_count = 0;
	t->smp_lock_pc = 0;
#endif

	/* Calculate offset to stack_frame & pt_regs */
	child_trap_frame = ((char *)p) + (THREAD_SIZE - (TRACEREG_SZ+REGWIN_SZ));
	memcpy(child_trap_frame, (((struct reg_window *)regs)-1), (TRACEREG_SZ+REGWIN_SZ));
	t->ksp = ((unsigned long) child_trap_frame) - STACK_BIAS;
	t->flags |= SPARC_FLAG_NEWCHILD;
	t->kregs = (struct pt_regs *)(child_trap_frame+sizeof(struct reg_window));
	t->cwp = (regs->tstate + 1) & TSTATE_CWP;
	t->fpsaved[0] = 0;

	if (regs->tstate & TSTATE_PRIV) {
		/* Special case, if we are spawning a kernel thread from
		 * a userspace task (via KMOD, NFS, or similar) we must
		 * disable performance counters in the child because the
		 * address space and protection realm are changing.
		 */
		if (t->flags & SPARC_FLAG_PERFCTR) {
			t->user_cntd0 = t->user_cntd1 = NULL;
			t->pcr_reg = 0;
			t->flags &= ~(SPARC_FLAG_PERFCTR);
		}
		t->kregs->u_regs[UREG_FP] = p->thread.ksp;
		t->current_ds = KERNEL_DS;
		flush_register_windows();
		memcpy((void *)(t->ksp + STACK_BIAS),
		       (void *)(regs->u_regs[UREG_FP] + STACK_BIAS),
		       sizeof(struct reg_window));
		t->kregs->u_regs[UREG_G6] = (unsigned long) p;
	} else {
		if (t->flags & SPARC_FLAG_32BIT) {
			sp &= 0x00000000ffffffffUL;
			regs->u_regs[UREG_FP] &= 0x00000000ffffffffUL;
		}
		t->kregs->u_regs[UREG_FP] = sp;
		t->current_ds = USER_DS;
		if (sp != regs->u_regs[UREG_FP]) {
			unsigned long csp;

			csp = clone_stackframe(sp, regs->u_regs[UREG_FP]);
			if (!csp)
				return -EFAULT;
			t->kregs->u_regs[UREG_FP] = csp;
		}
		if (t->utraps)
			t->utraps[0]++;
	}

	/* Set the return value for the child. */
	t->kregs->u_regs[UREG_I0] = current->pid;
	t->kregs->u_regs[UREG_I1] = 1;

	/* Set the second return value for the parent. */
	regs->u_regs[UREG_I1] = 0;

	return 0;
}

/*
 * This is the mechanism for creating a new kernel thread.
 *
 * NOTE! Only a kernel-only process(ie the swapper or direct descendants
 * who haven't done an "execve()") should use this: it will work within
 * a system call from a "real" process, but the process memory space will
 * not be free'd until both the parent and the child have exited.
 */
pid_t kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
{
	long retval;

	/* If the parent runs before fn(arg) is called by the child,
	 * the input registers of this function can be clobbered.
	 * So we stash 'fn' and 'arg' into global registers which
	 * will not be modified by the parent.
	 */
	__asm__ __volatile("mov %4, %%g2\n\t"	   /* Save FN into global */
			   "mov %5, %%g3\n\t"	   /* Save ARG into global */
			   "mov %1, %%g1\n\t"	   /* Clone syscall nr. */
			   "mov %2, %%o0\n\t"	   /* Clone flags. */
			   "mov 0, %%o1\n\t"	   /* usp arg == 0 */
			   "t 0x6d\n\t"		   /* Linux/Sparc clone(). */
			   "brz,a,pn %%o1, 1f\n\t" /* Parent, just return. */
			   " mov %%o0, %0\n\t"
			   "jmpl %%g2, %%o7\n\t"   /* Call the function. */
			   " mov %%g3, %%o0\n\t"   /* Set arg in delay. */
			   "mov %3, %%g1\n\t"
			   "t 0x6d\n\t"		   /* Linux/Sparc exit(). */
			   /* Notreached by child. */
			   "1:" :
			   "=r" (retval) :
			   "i" (__NR_clone), "r" (flags | CLONE_VM),
			   "i" (__NR_exit),  "r" (fn), "r" (arg) :
			   "g1", "g2", "g3", "o0", "o1", "memory", "cc");
	return retval;
}

/*
 * fill in the user structure for a core dump..
 */
void dump_thread(struct pt_regs * regs, struct user * dump)
{
#if 1
	/* Only should be used for SunOS and ancient a.out
	 * SparcLinux binaries...  Fixme some day when bored.
	 * But for now at least plug the security hole :-)
	 */
	memset(dump, 0, sizeof(struct user));
#else
	unsigned long first_stack_page;
	dump->magic = SUNOS_CORE_MAGIC;
	dump->len = sizeof(struct user);
	dump->regs.psr = regs->psr;
	dump->regs.pc = regs->pc;
	dump->regs.npc = regs->npc;
	dump->regs.y = regs->y;
	/* fuck me plenty */
	memcpy(&dump->regs.regs[0], &regs->u_regs[1], (sizeof(unsigned long) * 15));
	dump->u_tsize = (((unsigned long) current->mm->end_code) -
		((unsigned long) current->mm->start_code)) & ~(PAGE_SIZE - 1);
	dump->u_dsize = ((unsigned long) (current->mm->brk + (PAGE_SIZE-1)));
	dump->u_dsize -= dump->u_tsize;
	dump->u_dsize &= ~(PAGE_SIZE - 1);
	first_stack_page = (regs->u_regs[UREG_FP] & ~(PAGE_SIZE - 1));
	dump->u_ssize = (TASK_SIZE - first_stack_page) & ~(PAGE_SIZE - 1);
	memcpy(&dump->fpu.fpstatus.fregs.regs[0], &current->thread.float_regs[0], (sizeof(unsigned long) * 32));
	dump->fpu.fpstatus.fsr = current->thread.fsr;
	dump->fpu.fpstatus.flags = dump->fpu.fpstatus.extra = 0;
#endif	
}

typedef struct {
	union {
		unsigned int	pr_regs[32];
		unsigned long	pr_dregs[16];
	} pr_fr;
	unsigned int __unused;
	unsigned int	pr_fsr;
	unsigned char	pr_qcnt;
	unsigned char	pr_q_entrysize;
	unsigned char	pr_en;
	unsigned int	pr_q[64];
} elf_fpregset_t32;

/*
 * fill in the fpu structure for a core dump.
 */
int dump_fpu (struct pt_regs * regs, elf_fpregset_t * fpregs)
{
	unsigned long *kfpregs = (unsigned long *)(((char *)current) + AOFF_task_fpregs);
	unsigned long fprs = current->thread.fpsaved[0];

	if ((current->thread.flags & SPARC_FLAG_32BIT) != 0) {
		elf_fpregset_t32 *fpregs32 = (elf_fpregset_t32 *)fpregs;

		if (fprs & FPRS_DL)
			memcpy(&fpregs32->pr_fr.pr_regs[0], kfpregs,
			       sizeof(unsigned int) * 32);
		else
			memset(&fpregs32->pr_fr.pr_regs[0], 0,
			       sizeof(unsigned int) * 32);
		fpregs32->pr_qcnt = 0;
		fpregs32->pr_q_entrysize = 8;
		memset(&fpregs32->pr_q[0], 0,
		       (sizeof(unsigned int) * 64));
		if (fprs & FPRS_FEF) {
			fpregs32->pr_fsr = (unsigned int) current->thread.xfsr[0];
			fpregs32->pr_en = 1;
		} else {
			fpregs32->pr_fsr = 0;
			fpregs32->pr_en = 0;
		}
	} else {
		if(fprs & FPRS_DL)
			memcpy(&fpregs->pr_regs[0], kfpregs,
			       sizeof(unsigned int) * 32);
		else
			memset(&fpregs->pr_regs[0], 0,
			       sizeof(unsigned int) * 32);
		if(fprs & FPRS_DU)
			memcpy(&fpregs->pr_regs[16], kfpregs+16,
			       sizeof(unsigned int) * 32);
		else
			memset(&fpregs->pr_regs[16], 0,
			       sizeof(unsigned int) * 32);
		if(fprs & FPRS_FEF) {
			fpregs->pr_fsr = current->thread.xfsr[0];
			fpregs->pr_gsr = current->thread.gsr[0];
		} else {
			fpregs->pr_fsr = fpregs->pr_gsr = 0;
		}
		fpregs->pr_fprs = fprs;
	}
	return 1;
}

/*
 * sparc_execve() executes a new program after the asm stub has set
 * things up for us.  This should basically do what I want it to.
 */
asmlinkage int sparc_execve(struct pt_regs *regs)
{
	int error, base = 0;
	char *filename;

	/* User register window flush is done by entry.S */

	/* Check for indirect call. */
	if (regs->u_regs[UREG_G1] == 0)
		base = 1;

	filename = getname((char *)regs->u_regs[base + UREG_I0]);
	error = PTR_ERR(filename);
	if (IS_ERR(filename))
		goto out;
	error = do_execve(filename, (char **) regs->u_regs[base + UREG_I1],
			  (char **) regs->u_regs[base + UREG_I2], regs);
	putname(filename);
	if (!error) {
		fprs_write(0);
		current->thread.xfsr[0] = 0;
		current->thread.fpsaved[0] = 0;
		regs->tstate &= ~TSTATE_PEF;
	}
out:
	return error;
}