traps.c

linux 内核源代码

	printk(KERN_DEBUG "c0_depc = %0*lx, DEBUG = %08x\n", field, depc, debug);
	if (debug & 0x80000000) {
		/*
		 * In branch delay slot.
		 * We cheat a little bit here and use EPC to calculate the
		 * debug return address (DEPC). EPC is restored after the
		 * calculation.
		 */
		old_epc = regs->cp0_epc;
		regs->cp0_epc = depc;
		__compute_return_epc(regs);
		depc = regs->cp0_epc;
		regs->cp0_epc = old_epc;
	} else
		depc += 4;
	write_c0_depc(depc);

#if 0
	printk(KERN_DEBUG "\n\n----- Enable EJTAG single stepping ----\n\n");
	write_c0_debug(debug | 0x100);
#endif
}

/*
 * NMI exception handler.
 */
NORET_TYPE void ATTRIB_NORET nmi_exception_handler(struct pt_regs *regs)
{
	bust_spinlocks(1);
	printk("NMI taken!!!!\n");
	die("NMI", regs);
}

#define VECTORSPACING 0x100	/* for EI/VI mode */

unsigned long ebase;
unsigned long exception_handlers[32];
unsigned long vi_handlers[64];

/*
 * As a side effect of the way this is implemented we're limited
 * to interrupt handlers in the address range from
 * KSEG0 <= x < KSEG0 + 256mb on the Nevada.  Oh well ...
 */
void *set_except_vector(int n, void *addr)
{
	unsigned long handler = (unsigned long) addr;
	unsigned long old_handler = exception_handlers[n];

	exception_handlers[n] = handler;
	if (n == 0 && cpu_has_divec) {
		*(u32 *)(ebase + 0x200) = 0x08000000 |
					  (0x03ffffff & (handler >> 2));
		flush_icache_range(ebase + 0x200, ebase + 0x204);
	}
	return (void *)old_handler;
}

static asmlinkage void do_default_vi(void)
{
	show_regs(get_irq_regs());
	panic("Caught unexpected vectored interrupt.");
}

static void *set_vi_srs_handler(int n, vi_handler_t addr, int srs)
{
	unsigned long handler;
	unsigned long old_handler = vi_handlers[n];
	int srssets = current_cpu_data.srsets;
	u32 *w;
	unsigned char *b;

	if (!cpu_has_veic && !cpu_has_vint)
		BUG();

	if (addr == NULL) {
		handler = (unsigned long) do_default_vi;
		srs = 0;
	} else
		handler = (unsigned long) addr;
	vi_handlers[n] = (unsigned long) addr;

	b = (unsigned char *)(ebase + 0x200 + n*VECTORSPACING);

	if (srs >= srssets)
		panic("Shadow register set %d not supported", srs);

	if (cpu_has_veic) {
		if (board_bind_eic_interrupt)
			board_bind_eic_interrupt(n, srs);
	} else if (cpu_has_vint) {
		/* SRSMap is only defined if shadow sets are implemented */
		if (srssets > 1)
			change_c0_srsmap(0xf << n*4, srs << n*4);
	}

	if (srs == 0) {
		/*
		 * If no shadow set is selected then use the default handler
		 * that does normal register saving and a standard interrupt exit
		 */

		extern char except_vec_vi, except_vec_vi_lui;
		extern char except_vec_vi_ori, except_vec_vi_end;
#ifdef CONFIG_MIPS_MT_SMTC
		/*
		 * We need to provide the SMTC vectored interrupt handler
		 * not only with the address of the handler, but with the
		 * Status.IM bit to be masked before going there.
		 */
		extern char except_vec_vi_mori;
		const int mori_offset = &except_vec_vi_mori - &except_vec_vi;
#endif /* CONFIG_MIPS_MT_SMTC */
		const int handler_len = &except_vec_vi_end - &except_vec_vi;
		const int lui_offset = &except_vec_vi_lui - &except_vec_vi;
		const int ori_offset = &except_vec_vi_ori - &except_vec_vi;

		if (handler_len > VECTORSPACING) {
			/*
			 * Sigh... panicing won't help as the console
			 * is probably not configured :(
			 */
			panic("VECTORSPACING too small");
		}

		memcpy(b, &except_vec_vi, handler_len);
#ifdef CONFIG_MIPS_MT_SMTC
		BUG_ON(n > 7);	/* Vector index %d exceeds SMTC maximum. */

		w = (u32 *)(b + mori_offset);
		*w = (*w & 0xffff0000) | (0x100 << n);
#endif /* CONFIG_MIPS_MT_SMTC */
		w = (u32 *)(b + lui_offset);
		*w = (*w & 0xffff0000) | (((u32)handler >> 16) & 0xffff);
		w = (u32 *)(b + ori_offset);
		*w = (*w & 0xffff0000) | ((u32)handler & 0xffff);
		flush_icache_range((unsigned long)b, (unsigned long)(b+handler_len));
	}
	else {
		/*
		 * In other cases jump directly to the interrupt handler
		 *
		 * It is the handlers responsibility to save registers if required
		 * (eg hi/lo) and return from the exception using "eret"
		 */
		w = (u32 *)b;
		*w++ = 0x08000000 | (((u32)handler >> 2) & 0x03fffff); /* j handler */
		*w = 0;
		flush_icache_range((unsigned long)b, (unsigned long)(b+8));
	}

	return (void *)old_handler;
}

void *set_vi_handler(int n, vi_handler_t addr)
{
	return set_vi_srs_handler(n, addr, 0);
}

/*
 * This is used by native signal handling
 */
asmlinkage int (*save_fp_context)(struct sigcontext __user *sc);
asmlinkage int (*restore_fp_context)(struct sigcontext __user *sc);

extern asmlinkage int _save_fp_context(struct sigcontext __user *sc);
extern asmlinkage int _restore_fp_context(struct sigcontext __user *sc);

extern asmlinkage int fpu_emulator_save_context(struct sigcontext __user *sc);
extern asmlinkage int fpu_emulator_restore_context(struct sigcontext __user *sc);

#ifdef CONFIG_SMP
static int smp_save_fp_context(struct sigcontext __user *sc)
{
	return raw_cpu_has_fpu
	       ? _save_fp_context(sc)
	       : fpu_emulator_save_context(sc);
}

static int smp_restore_fp_context(struct sigcontext __user *sc)
{
	return raw_cpu_has_fpu
	       ? _restore_fp_context(sc)
	       : fpu_emulator_restore_context(sc);
}
#endif

static inline void signal_init(void)
{
#ifdef CONFIG_SMP
	/* For now just do the cpu_has_fpu check when the functions are invoked */
	save_fp_context = smp_save_fp_context;
	restore_fp_context = smp_restore_fp_context;
#else
	if (cpu_has_fpu) {
		save_fp_context = _save_fp_context;
		restore_fp_context = _restore_fp_context;
	} else {
		save_fp_context = fpu_emulator_save_context;
		restore_fp_context = fpu_emulator_restore_context;
	}
#endif
}

#ifdef CONFIG_MIPS32_COMPAT

/*
 * This is used by 32-bit signal stuff on the 64-bit kernel
 */
asmlinkage int (*save_fp_context32)(struct sigcontext32 __user *sc);
asmlinkage int (*restore_fp_context32)(struct sigcontext32 __user *sc);

extern asmlinkage int _save_fp_context32(struct sigcontext32 __user *sc);
extern asmlinkage int _restore_fp_context32(struct sigcontext32 __user *sc);

extern asmlinkage int fpu_emulator_save_context32(struct sigcontext32 __user *sc);
extern asmlinkage int fpu_emulator_restore_context32(struct sigcontext32 __user *sc);

static inline void signal32_init(void)
{
	if (cpu_has_fpu) {
		save_fp_context32 = _save_fp_context32;
		restore_fp_context32 = _restore_fp_context32;
	} else {
		save_fp_context32 = fpu_emulator_save_context32;
		restore_fp_context32 = fpu_emulator_restore_context32;
	}
}
#endif

extern void cpu_cache_init(void);
extern void tlb_init(void);
extern void flush_tlb_handlers(void);

/*
 * Timer interrupt
 */
int cp0_compare_irq;

/*
 * Performance counter IRQ or -1 if shared with timer
 */
int cp0_perfcount_irq;
EXPORT_SYMBOL_GPL(cp0_perfcount_irq);

void __init per_cpu_trap_init(void)
{
	unsigned int cpu = smp_processor_id();
	unsigned int status_set = ST0_CU0;
#ifdef CONFIG_MIPS_MT_SMTC
	int secondaryTC = 0;
	int bootTC = (cpu == 0);

	/*
	 * Only do per_cpu_trap_init() for first TC of Each VPE.
	 * Note that this hack assumes that the SMTC init code
	 * assigns TCs consecutively and in ascending order.
	 */

	if (((read_c0_tcbind() & TCBIND_CURTC) != 0) &&
	    ((read_c0_tcbind() & TCBIND_CURVPE) == cpu_data[cpu - 1].vpe_id))
		secondaryTC = 1;
#endif /* CONFIG_MIPS_MT_SMTC */

	/*
	 * Disable coprocessors and select 32-bit or 64-bit addressing
	 * and the 16/32 or 32/32 FPR register model.  Reset the BEV
	 * flag that some firmware may have left set and the TS bit (for
	 * IP27).  Set XX for ISA IV code to work.
	 */
#ifdef CONFIG_64BIT
	status_set |= ST0_FR|ST0_KX|ST0_SX|ST0_UX;
#endif
	if (current_cpu_data.isa_level == MIPS_CPU_ISA_IV)
		status_set |= ST0_XX;
	if (cpu_has_dsp)
		status_set |= ST0_MX;

	change_c0_status(ST0_CU|ST0_MX|ST0_RE|ST0_FR|ST0_BEV|ST0_TS|ST0_KX|ST0_SX|ST0_UX,
			 status_set);

#ifdef CONFIG_CPU_MIPSR2
	if (cpu_has_mips_r2) {
		unsigned int enable = 0x0000000f;

		if (cpu_has_userlocal)
			enable |= (1 << 29);

		write_c0_hwrena(enable);
	}
#endif

#ifdef CONFIG_MIPS_MT_SMTC
	if (!secondaryTC) {
#endif /* CONFIG_MIPS_MT_SMTC */

	if (cpu_has_veic || cpu_has_vint) {
		write_c0_ebase(ebase);
		/* Setting vector spacing enables EI/VI mode  */
		change_c0_intctl(0x3e0, VECTORSPACING);
	}
	if (cpu_has_divec) {
		if (cpu_has_mipsmt) {
			unsigned int vpflags = dvpe();
			set_c0_cause(CAUSEF_IV);
			evpe(vpflags);
		} else
			set_c0_cause(CAUSEF_IV);
	}

	/*
	 * Before R2 both interrupt numbers were fixed to 7, so on R2 only:
	 *
	 *  o read IntCtl.IPTI to determine the timer interrupt
	 *  o read IntCtl.IPPCI to determine the performance counter interrupt
	 */
	if (cpu_has_mips_r2) {
		cp0_compare_irq = (read_c0_intctl() >> 29) & 7;
		cp0_perfcount_irq = (read_c0_intctl() >> 26) & 7;
		if (cp0_perfcount_irq == cp0_compare_irq)
			cp0_perfcount_irq = -1;
	} else {
		cp0_compare_irq = CP0_LEGACY_COMPARE_IRQ;
		cp0_perfcount_irq = -1;
	}

#ifdef CONFIG_MIPS_MT_SMTC
	}
#endif /* CONFIG_MIPS_MT_SMTC */

	cpu_data[cpu].asid_cache = ASID_FIRST_VERSION;
	TLBMISS_HANDLER_SETUP();

	atomic_inc(&init_mm.mm_count);
	current->active_mm = &init_mm;
	BUG_ON(current->mm);
	enter_lazy_tlb(&init_mm, current);

#ifdef CONFIG_MIPS_MT_SMTC
	if (bootTC) {
#endif /* CONFIG_MIPS_MT_SMTC */
		cpu_cache_init();
		tlb_init();
#ifdef CONFIG_MIPS_MT_SMTC
	} else if (!secondaryTC) {
		/*
		 * First TC in non-boot VPE must do subset of tlb_init()
		 * for MMU countrol registers.
		 */
		write_c0_pagemask(PM_DEFAULT_MASK);
		write_c0_wired(0);
	}
#endif /* CONFIG_MIPS_MT_SMTC */
}

/* Install CPU exception handler */
void __init set_handler(unsigned long offset, void *addr, unsigned long size)
{
	memcpy((void *)(ebase + offset), addr, size);
	flush_icache_range(ebase + offset, ebase + offset + size);
}

static char panic_null_cerr[] __initdata =
	"Trying to set NULL cache error exception handler";

/* Install uncached CPU exception handler */
void __init set_uncached_handler(unsigned long offset, void *addr, unsigned long size)
{
#ifdef CONFIG_32BIT
	unsigned long uncached_ebase = KSEG1ADDR(ebase);
#endif
#ifdef CONFIG_64BIT
	unsigned long uncached_ebase = TO_UNCAC(ebase);
#endif

	if (!addr)
		panic(panic_null_cerr);

	memcpy((void *)(uncached_ebase + offset), addr, size);
}

static int __initdata rdhwr_noopt;
static int __init set_rdhwr_noopt(char *str)
{
	rdhwr_noopt = 1;
	return 1;
}

__setup("rdhwr_noopt", set_rdhwr_noopt);

void __init trap_init(void)
{
	extern char except_vec3_generic, except_vec3_r4000;
	extern char except_vec4;
	unsigned long i;

	if (cpu_has_veic || cpu_has_vint)
		ebase = (unsigned long) alloc_bootmem_low_pages(0x200 + VECTORSPACING*64);
	else
		ebase = CAC_BASE;

	per_cpu_trap_init();

	/*
	 * Copy the generic exception handlers to their final destination.
	 * This will be overriden later as suitable for a particular
	 * configuration.
	 */
	set_handler(0x180, &except_vec3_generic, 0x80);

	/*
	 * Setup default vectors
	 */
	for (i = 0; i <= 31; i++)
		set_except_vector(i, handle_reserved);

	/*
	 * Copy the EJTAG debug exception vector handler code to it's final
	 * destination.
	 */
	if (cpu_has_ejtag && board_ejtag_handler_setup)
		board_ejtag_handler_setup();

	/*
	 * Only some CPUs have the watch exceptions.
	 */
	if (cpu_has_watch)
		set_except_vector(23, handle_watch);

	/*
	 * Initialise interrupt handlers
	 */
	if (cpu_has_veic || cpu_has_vint) {
		int nvec = cpu_has_veic ? 64 : 8;
		for (i = 0; i < nvec; i++)
			set_vi_handler(i, NULL);
	}
	else if (cpu_has_divec)
		set_handler(0x200, &except_vec4, 0x8);

	/*
	 * Some CPUs can enable/disable for cache parity detection, but does
	 * it different ways.
	 */
	parity_protection_init();

	/*
	 * The Data Bus Errors / Instruction Bus Errors are signaled
	 * by external hardware.  Therefore these two exceptions
	 * may have board specific handlers.
	 */
	if (board_be_init)
		board_be_init();

	set_except_vector(0, handle_int);
	set_except_vector(1, handle_tlbm);
	set_except_vector(2, handle_tlbl);
	set_except_vector(3, handle_tlbs);

	set_except_vector(4, handle_adel);
	set_except_vector(5, handle_ades);

	set_except_vector(6, handle_ibe);
	set_except_vector(7, handle_dbe);

	set_except_vector(8, handle_sys);
	set_except_vector(9, handle_bp);
	set_except_vector(10, rdhwr_noopt ? handle_ri :
			  (cpu_has_vtag_icache ?
			   handle_ri_rdhwr_vivt : handle_ri_rdhwr));
	set_except_vector(11, handle_cpu);
	set_except_vector(12, handle_ov);
	set_except_vector(13, handle_tr);

	if (current_cpu_type() == CPU_R6000 ||
	    current_cpu_type() == CPU_R6000A) {
		/*
		 * The R6000 is the only R-series CPU that features a machine
		 * check exception (similar to the R4000 cache error) and
		 * unaligned ldc1/sdc1 exception.  The handlers have not been
		 * written yet.  Well, anyway there is no R6000 machine on the
		 * current list of targets for Linux/MIPS.
		 * (Duh, crap, there is someone with a triple R6k machine)
		 */
		//set_except_vector(14, handle_mc);
		//set_except_vector(15, handle_ndc);
	}


	if (board_nmi_handler_setup)
		board_nmi_handler_setup();

	if (cpu_has_fpu && !cpu_has_nofpuex)
		set_except_vector(15, handle_fpe);

	set_except_vector(22, handle_mdmx);

	if (cpu_has_mcheck)
		set_except_vector(24, handle_mcheck);

	if (cpu_has_mipsmt)
		set_except_vector(25, handle_mt);

	set_except_vector(26, handle_dsp);

	if (cpu_has_vce)
		/* Special exception: R4[04]00 uses also the divec space. */
		memcpy((void *)(CAC_BASE + 0x180), &except_vec3_r4000, 0x100);
	else if (cpu_has_4kex)
		memcpy((void *)(CAC_BASE + 0x180), &except_vec3_generic, 0x80);
	else
		memcpy((void *)(CAC_BASE + 0x080), &except_vec3_generic, 0x80);

	signal_init();
#ifdef CONFIG_MIPS32_COMPAT
	signal32_init();
#endif

	flush_icache_range(ebase, ebase + 0x400);
	flush_tlb_handlers();
}