powerpc/kernel/head_book3s_32.S

1 /* SPDX-License-Identifier: GPL-2.0-or-later */
4  *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
9  *  Low-level exception handlers and MMU support
14  *  This file contains the low-level support and setup for the
30 #include <asm/asm-offsets.h>
34 #include <asm/feature-fixups.h>
40 	/* see the comment for clear_bats() -- Cort */ \
65 	 *  -- Cort
77  * pointer (r1) points to just below the end of the half-meg region
78  * from 0x380000 - 0x400000, which is mapped in already.
92  *   r5: initrd_end - unused if r4 is 0
98  * -- Cort
115 	addis	r8,r8,(_stext - 0b)@ha
116 	addi	r8,r8,(_stext - 0b)@l	/* current runtime base addr */
138 	li	r24,0			/* cpu # */
142  * the necessary low-level setup and clears the BSS
143  *  -- Cort <cort@fsmlabs.com>
170  * Call setup_cpu for CPU 0 and initialize 6xx Idle
173 	li	r24,0			/* cpu# */
174 	bl	call_setup_cpu		/* Call setup_cpu for this CPU */
182  * the exception vectors at 0 (and therefore this copy
183  * overwrites OF's exception vectors with our own).
196  * as we jump to our code at KERNELBASE. -- Cort
214 	li	r3,1			/* MTX only has 1 cpu */
224 	/* our cpu # was at addr 0 - go */
225 	mr	r24,r3			/* cpu # */
236 	.long	-1
250  * a non-zero value, the address of the exception frame to use,
252  * and uses its value if it is non-zero.
255  *	-- paulus.
303 	bne-	1f
359 /* Floating-point unavailable */
398  * non-altivec kernel running on a machine with altivec just
410  * Note: we get an alternate set of r0 - r3 to use automatically.
414 	/* Get PTE (linux-style) and check access */
426 	beq-	InstructionAddressInvalid	/* return if no mapping */
428 	lwz	r2,0(r2)		/* get linux-style pte */
430 	bne-	InstructionAddressInvalid /* return if access not permitted */
431 	/* Convert linux-style PTE to low word of PPC-style PTE */
433 	rlwimi	r2, r3, 1, 31, 31	/* userspace ? -> PP lsb */
435 	ori	r1, r1, 0xe06		/* clear out reserved bits */
456 	rlwimi	r2,r2,1,30,30	/* change 1 -> 3 */
470 	/* Get PTE (linux-style) and check access */
479 	beq-	2f			/* bail if no mapping */
481 	lwz	r2,0(r2)		/* get linux-style pte */
484 	bne-	DataAddressInvalid	/* return if access not permitted */
485 	/* Convert linux-style PTE to low word of PPC-style PTE */
486 	rlwinm	r1,r2,32-9,30,30	/* _PAGE_WRITE -> PP msb */
487 	rlwimi	r2,r3,2,30,31		/* userspace ? -> PP */
488 	rlwimi	r1,r2,32-3,24,24	/* _PAGE_WRITE -> _PAGE_DIRTY */
490 	ori	r1,r1,0xe04		/* clear out reserved bits */
505 	rlwimi	r2,r3,31-14,14,14
517 2:	lis     r2, (swapper_pg_dir - PAGE_OFFSET)@ha
518 	addi    r2, r2, (swapper_pg_dir - PAGE_OFFSET)@l        /* kernel page table */
522 	beq-	DataAddressInvalid	/* return if no mapping */
549 	/* Get PTE (linux-style) and check access */
558 	beq-	2f			/* bail if no mapping */
561 	lwz	r2,0(r2)		/* get linux-style pte */
564 	bne-	DataAddressInvalid	/* return if access not permitted */
565 	/* Convert linux-style PTE to low word of PPC-style PTE */
566 	rlwimi	r2,r3,1,31,31		/* userspace ? -> PP lsb */
567 	li	r1,0xe06		/* clear out reserved bits & PP msb */
584 	rlwimi	r2,r3,31-14,14,14
596 2:	lis     r2, (swapper_pg_dir - PAGE_OFFSET)@ha
597 	addi    r2, r2, (swapper_pg_dir - PAGE_OFFSET)@l        /* kernel page table */
601 	beq-	DataAddressInvalid	/* return if no mapping */
682 	rlwinm	r3, r3, 32 - 15, _PAGE_WRITE	/* DSISR_STORE -> _PAGE_WRITE */
759 4:	lis	r5,_end-KERNELBASE@h
760 	ori	r5,r5,_end-KERNELBASE@l
771 	addi	r5,r5,-4
772 	addi	r6,r6,-4
795 	mr	r24, r3			/* cpu # */
810 	   set to map the 0xf0000000 - 0xffffffff region */
818 	/* Copy some CPU settings from CPU 0 */
821 	lis	r3,-KERNELBASE@h
823 	bl	call_setup_cpu		/* Call setup_cpu for this CPU */
824 	lis	r3,-KERNELBASE@h
835 	addi	r1,r1,THREAD_SIZE-STACK_FRAME_MIN_SIZE
849 	lis	r4, (swapper_pg_dir - PAGE_OFFSET)@h
850 	ori	r4, r4, (swapper_pg_dir - PAGE_OFFSET)@l
879 	lis	r6, early_hash - PAGE_OFFSET@h
929 	li	r0, 16 - NUM_USER_SEGMENTS /* load up kernel segment registers */
947 	/* Set up for using our exception vectors */
953 	lis	r4, (swapper_pg_dir - PAGE_OFFSET)@h
954 	ori	r4, r4, (swapper_pg_dir - PAGE_OFFSET)@l
963 	stwu	r0,THREAD_SIZE-STACK_FRAME_MIN_SIZE(r1)
965  * Do early platform-specific initialization,
981  * and change to using our exception vectors.
1023  *  -- Cort
1045 	/* Here's a tweak: at this point, CPU setup have
1108 1:	addic.	r10, r10, -0x1000
1116  	addi	r4, r3, __after_mmu_off - _start