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Diffstat (limited to 'arch/mips/kernel/head.S')
| -rw-r--r-- | arch/mips/kernel/head.S | 232 |
1 files changed, 232 insertions, 0 deletions
diff --git a/arch/mips/kernel/head.S b/arch/mips/kernel/head.S new file mode 100644 index 00000000..ea695d96 --- /dev/null +++ b/arch/mips/kernel/head.S @@ -0,0 +1,232 @@ +/* + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + * + * Copyright (C) 1994, 1995 Waldorf Electronics + * Written by Ralf Baechle and Andreas Busse + * Copyright (C) 1994 - 99, 2003, 06 Ralf Baechle + * Copyright (C) 1996 Paul M. Antoine + * Modified for DECStation and hence R3000 support by Paul M. Antoine + * Further modifications by David S. Miller and Harald Koerfgen + * Copyright (C) 1999 Silicon Graphics, Inc. + * Kevin Kissell, kevink@mips.com and Carsten Langgaard, carstenl@mips.com + * Copyright (C) 2000 MIPS Technologies, Inc. All rights reserved. + */ +#include <linux/init.h> +#include <linux/threads.h> + +#include <asm/addrspace.h> +#include <asm/asm.h> +#include <asm/asmmacro.h> +#include <asm/irqflags.h> +#include <asm/regdef.h> +#include <asm/page.h> +#include <asm/pgtable-bits.h> +#include <asm/mipsregs.h> +#include <asm/stackframe.h> + +#include <kernel-entry-init.h> + + /* + * inputs are the text nasid in t1, data nasid in t2. + */ + .macro MAPPED_KERNEL_SETUP_TLB +#ifdef CONFIG_MAPPED_KERNEL + /* + * This needs to read the nasid - assume 0 for now. + * Drop in 0xffffffffc0000000 in tlbhi, 0+VG in tlblo_0, + * 0+DVG in tlblo_1. + */ + dli t0, 0xffffffffc0000000 + dmtc0 t0, CP0_ENTRYHI + li t0, 0x1c000 # Offset of text into node memory + dsll t1, NASID_SHFT # Shift text nasid into place + dsll t2, NASID_SHFT # Same for data nasid + or t1, t1, t0 # Physical load address of kernel text + or t2, t2, t0 # Physical load address of kernel data + dsrl t1, 12 # 4K pfn + dsrl t2, 12 # 4K pfn + dsll t1, 6 # Get pfn into place + dsll t2, 6 # Get pfn into place + li t0, ((_PAGE_GLOBAL|_PAGE_VALID| _CACHE_CACHABLE_COW) >> 6) + or t0, t0, t1 + mtc0 t0, CP0_ENTRYLO0 # physaddr, VG, cach exlwr + li t0, ((_PAGE_GLOBAL|_PAGE_VALID| _PAGE_DIRTY|_CACHE_CACHABLE_COW) >> 6) + or t0, t0, t2 + mtc0 t0, CP0_ENTRYLO1 # physaddr, DVG, cach exlwr + li t0, 0x1ffe000 # MAPPED_KERN_TLBMASK, TLBPGMASK_16M + mtc0 t0, CP0_PAGEMASK + li t0, 0 # KMAP_INX + mtc0 t0, CP0_INDEX + li t0, 1 + mtc0 t0, CP0_WIRED + tlbwi +#else + mtc0 zero, CP0_WIRED +#endif + .endm + + /* + * For the moment disable interrupts, mark the kernel mode and + * set ST0_KX so that the CPU does not spit fire when using + * 64-bit addresses. A full initialization of the CPU's status + * register is done later in per_cpu_trap_init(). + */ + .macro setup_c0_status set clr + .set push +#ifdef CONFIG_MIPS_MT_SMTC + /* + * For SMTC, we need to set privilege and disable interrupts only for + * the current TC, using the TCStatus register. + */ + mfc0 t0, CP0_TCSTATUS + /* Fortunately CU 0 is in the same place in both registers */ + /* Set TCU0, TMX, TKSU (for later inversion) and IXMT */ + li t1, ST0_CU0 | 0x08001c00 + or t0, t1 + /* Clear TKSU, leave IXMT */ + xori t0, 0x00001800 + mtc0 t0, CP0_TCSTATUS + _ehb + /* We need to leave the global IE bit set, but clear EXL...*/ + mfc0 t0, CP0_STATUS + or t0, ST0_CU0 | ST0_EXL | ST0_ERL | \set | \clr + xor t0, ST0_EXL | ST0_ERL | \clr + mtc0 t0, CP0_STATUS +#else + mfc0 t0, CP0_STATUS + or t0, ST0_CU0|\set|0x1f|\clr + xor t0, 0x1f|\clr + mtc0 t0, CP0_STATUS + .set noreorder + sll zero,3 # ehb +#endif + .set pop + .endm + + .macro setup_c0_status_pri +#ifdef CONFIG_64BIT + setup_c0_status ST0_KX 0 +#else + setup_c0_status 0 0 +#endif + .endm + + .macro setup_c0_status_sec +#ifdef CONFIG_64BIT + setup_c0_status ST0_KX ST0_BEV +#else + setup_c0_status 0 ST0_BEV +#endif + .endm + +#ifndef CONFIG_NO_EXCEPT_FILL + /* + * Reserved space for exception handlers. + * Necessary for machines which link their kernels at KSEG0. + */ + .fill 0x400 +#endif + +EXPORT(_stext) + +#ifdef CONFIG_BOOT_RAW + /* + * Give us a fighting chance of running if execution beings at the + * kernel load address. This is needed because this platform does + * not have a ELF loader yet. + */ +FEXPORT(__kernel_entry) + j kernel_entry +#endif + + __REF + +NESTED(kernel_entry, 16, sp) # kernel entry point + + kernel_entry_setup # cpu specific setup + + setup_c0_status_pri + + /* We might not get launched at the address the kernel is linked to, + so we jump there. */ + PTR_LA t0, 0f + jr t0 +0: + +#ifdef CONFIG_MIPS_MT_SMTC + /* + * In SMTC kernel, "CLI" is thread-specific, in TCStatus. + * We still need to enable interrupts globally in Status, + * and clear EXL/ERL. + * + * TCContext is used to track interrupt levels under + * service in SMTC kernel. Clear for boot TC before + * allowing any interrupts. + */ + mtc0 zero, CP0_TCCONTEXT + + mfc0 t0, CP0_STATUS + ori t0, t0, 0xff1f + xori t0, t0, 0x001e + mtc0 t0, CP0_STATUS +#endif /* CONFIG_MIPS_MT_SMTC */ + + PTR_LA t0, __bss_start # clear .bss + LONG_S zero, (t0) + PTR_LA t1, __bss_stop - LONGSIZE +1: + PTR_ADDIU t0, LONGSIZE + LONG_S zero, (t0) + bne t0, t1, 1b + + LONG_S a0, fw_arg0 # firmware arguments + LONG_S a1, fw_arg1 + LONG_S a2, fw_arg2 + LONG_S a3, fw_arg3 + + MTC0 zero, CP0_CONTEXT # clear context register + PTR_LA $28, init_thread_union + /* Set the SP after an empty pt_regs. */ + PTR_LI sp, _THREAD_SIZE - 32 - PT_SIZE + PTR_ADDU sp, $28 + back_to_back_c0_hazard + set_saved_sp sp, t0, t1 + PTR_SUBU sp, 4 * SZREG # init stack pointer + + j start_kernel + END(kernel_entry) + + __CPUINIT + +#ifdef CONFIG_SMP +/* + * SMP slave cpus entry point. Board specific code for bootstrap calls this + * function after setting up the stack and gp registers. + */ +NESTED(smp_bootstrap, 16, sp) +#ifdef CONFIG_MIPS_MT_SMTC + /* + * Read-modify-writes of Status must be atomic, and this + * is one case where CLI is invoked without EXL being + * necessarily set. The CLI and setup_c0_status will + * in fact be redundant for all but the first TC of + * each VPE being booted. + */ + DMT 10 # dmt t2 /* t0, t1 are used by CLI and setup_c0_status() */ + jal mips_ihb +#endif /* CONFIG_MIPS_MT_SMTC */ + setup_c0_status_sec + smp_slave_setup +#ifdef CONFIG_MIPS_MT_SMTC + andi t2, t2, VPECONTROL_TE + beqz t2, 2f + EMT # emt +2: +#endif /* CONFIG_MIPS_MT_SMTC */ + j start_secondary + END(smp_bootstrap) +#endif /* CONFIG_SMP */ + + __FINIT |