arch/powerpc/kernel/misc_32.S

/*
 * This file contains miscellaneous low-level functions.
 *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
 *
 * Largely rewritten by Cort Dougan (cort@cs.nmt.edu)
 * and Paul Mackerras.
 *
 * kexec bits:
 * Copyright (C) 2002-2003 Eric Biederman  <ebiederm@xmission.com>
 * GameCube/ppc32 port Copyright (C) 2004 Albert Herranz
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 *
 */

#include <linux/sys.h>
#include <asm/unistd.h>
#include <asm/errno.h>
#include <asm/reg.h>
#include <asm/page.h>
#include <asm/cache.h>
#include <asm/cputable.h>
#include <asm/mmu.h>
#include <asm/ppc_asm.h>
#include <asm/thread_info.h>
#include <asm/asm-offsets.h>
#include <asm/processor.h>
#include <asm/kexec.h>

	.text

/*
 * This returns the high 64 bits of the product of two 64-bit numbers.
 */
_GLOBAL(mulhdu)
	cmpwi	r6,0
	cmpwi	cr1,r3,0
	mr	r10,r4
	mulhwu	r4,r4,r5
	beq	1f
	mulhwu	r0,r10,r6
	mullw	r7,r10,r5
	addc	r7,r0,r7
	addze	r4,r4
1:	beqlr	cr1		/* all done if high part of A is 0 */
	mr	r10,r3
	mullw	r9,r3,r5
	mulhwu	r3,r3,r5
	beq	2f
	mullw	r0,r10,r6
	mulhwu	r8,r10,r6
	addc	r7,r0,r7
	adde	r4,r4,r8
	addze	r3,r3
2:	addc	r4,r4,r9
	addze	r3,r3
	blr

/*
 * sub_reloc_offset(x) returns x - reloc_offset().
 */
_GLOBAL(sub_reloc_offset)
	mflr	r0
	bl	1f
1:	mflr	r5
	lis	r4,1b@ha
	addi	r4,r4,1b@l
	subf	r5,r4,r5
	subf	r3,r5,r3
	mtlr	r0
	blr

/*
 * reloc_got2 runs through the .got2 section adding an offset
 * to each entry.
 */
_GLOBAL(reloc_got2)
	mflr	r11
	lis	r7,__got2_start@ha
	addi	r7,r7,__got2_start@l
	lis	r8,__got2_end@ha
	addi	r8,r8,__got2_end@l
	subf	r8,r7,r8
	srwi.	r8,r8,2
	beqlr
	mtctr	r8
	bl	1f
1:	mflr	r0
	lis	r4,1b@ha
	addi	r4,r4,1b@l
	subf	r0,r4,r0
	add	r7,r0,r7
2:	lwz	r0,0(r7)
	add	r0,r0,r3
	stw	r0,0(r7)
	addi	r7,r7,4
	bdnz	2b
	mtlr	r11
	blr

/*
 * call_setup_cpu - call the setup_cpu function for this cpu
 * r3 = data offset, r24 = cpu number
 *
 * Setup function is called with:
 *   r3 = data offset
 *   r4 = ptr to CPU spec (relocated)
 */
_GLOBAL(call_setup_cpu)
	addis	r4,r3,cur_cpu_spec@ha
	addi	r4,r4,cur_cpu_spec@l
	lwz	r4,0(r4)
	add	r4,r4,r3
	lwz	r5,CPU_SPEC_SETUP(r4)
	cmpwi	0,r5,0
	add	r5,r5,r3
	beqlr
	mtctr	r5
	bctr

#if defined(CONFIG_CPU_FREQ_PMAC) && defined(CONFIG_6xx)

/* This gets called by via-pmu.c to switch the PLL selection
 * on 750fx CPU. This function should really be moved to some
 * other place (as most of the cpufreq code in via-pmu
 */
_GLOBAL(low_choose_750fx_pll)
	/* Clear MSR:EE */
	mfmsr	r7
	rlwinm	r0,r7,0,17,15
	mtmsr	r0

	/* If switching to PLL1, disable HID0:BTIC */
	cmplwi	cr0,r3,0
	beq	1f
	mfspr	r5,SPRN_HID0
	rlwinm	r5,r5,0,27,25
	sync
	mtspr	SPRN_HID0,r5
	isync
	sync

1:
	/* Calc new HID1 value */
	mfspr	r4,SPRN_HID1	/* Build a HID1:PS bit from parameter */
	rlwinm	r5,r3,16,15,15	/* Clear out HID1:PS from value read */
	rlwinm	r4,r4,0,16,14	/* Could have I used rlwimi here ? */
	or	r4,r4,r5
	mtspr	SPRN_HID1,r4

	/* Store new HID1 image */
	rlwinm	r6,r1,0,0,18
	lwz	r6,TI_CPU(r6)
	slwi	r6,r6,2
	addis	r6,r6,nap_save_hid1@ha
	stw	r4,nap_save_hid1@l(r6)

	/* If switching to PLL0, enable HID0:BTIC */
	cmplwi	cr0,r3,0
	bne	1f
	mfspr	r5,SPRN_HID0
	ori	r5,r5,HID0_BTIC
	sync
	mtspr	SPRN_HID0,r5
	isync
	sync

1:
	/* Return */
	mtmsr	r7
	blr

_GLOBAL(low_choose_7447a_dfs)
	/* Clear MSR:EE */
	mfmsr	r7
	rlwinm	r0,r7,0,17,15
	mtmsr	r0
	
	/* Calc new HID1 value */
	mfspr	r4,SPRN_HID1
	insrwi	r4,r3,1,9	/* insert parameter into bit 9 */
	sync
	mtspr	SPRN_HID1,r4
	sync
	isync

	/* Return */
	mtmsr	r7
	blr

#endif /* CONFIG_CPU_FREQ_PMAC && CONFIG_6xx */

/*
 * complement mask on the msr then "or" some values on.
 *     _nmask_and_or_msr(nmask, value_to_or)
 */
_GLOBAL(_nmask_and_or_msr)
	mfmsr	r0		/* Get current msr */
	andc	r0,r0,r3	/* And off the bits set in r3 (first parm) */
	or	r0,r0,r4	/* Or on the bits in r4 (second parm) */
	SYNC			/* Some chip revs have problems here... */
	mtmsr	r0		/* Update machine state */
	isync
	blr			/* Done */


/*
 * Flush MMU TLB
 */
_GLOBAL(_tlbia)
#if defined(CONFIG_40x)
	sync			/* Flush to memory before changing mapping */
	tlbia
	isync			/* Flush shadow TLB */
#elif defined(CONFIG_44x)
	li	r3,0
	sync

	/* Load high watermark */
	lis	r4,tlb_44x_hwater@ha
	lwz	r5,tlb_44x_hwater@l(r4)

1:	tlbwe	r3,r3,PPC44x_TLB_PAGEID
	addi	r3,r3,1
	cmpw	0,r3,r5
	ble	1b

	isync
#elif defined(CONFIG_FSL_BOOKE)
	/* Invalidate all entries in TLB0 */
	li	r3, 0x04
	tlbivax	0,3
	/* Invalidate all entries in TLB1 */
	li	r3, 0x0c
	tlbivax	0,3
	/* Invalidate all entries in TLB2 */
	li	r3, 0x14
	tlbivax	0,3
	/* Invalidate all entries in TLB3 */
	li	r3, 0x1c
	tlbivax	0,3
	msync
#ifdef CONFIG_SMP
	tlbsync
#endif /* CONFIG_SMP */
#else /* !(CONFIG_40x || CONFIG_44x || CONFIG_FSL_BOOKE) */
#if defined(CONFIG_SMP)
	rlwinm	r8,r1,0,0,18
	lwz	r8,TI_CPU(r8)
	oris	r8,r8,10
	mfmsr	r10
	SYNC
	rlwinm	r0,r10,0,17,15		/* clear bit 16 (MSR_EE) */
	rlwinm	r0,r0,0,28,26		/* clear DR */
	mtmsr	r0
	SYNC_601
	isync
	lis	r9,mmu_hash_lock@h
	ori	r9,r9,mmu_hash_lock@l
	tophys(r9,r9)
10:	lwarx	r7,0,r9
	cmpwi	0,r7,0
	bne-	10b
	stwcx.	r8,0,r9
	bne-	10b
	sync
	tlbia
	sync
	TLBSYNC
	li	r0,0
	stw	r0,0(r9)		/* clear mmu_hash_lock */
	mtmsr	r10
	SYNC_601
	isync
#else /* CONFIG_SMP */
	sync
	tlbia
	sync
#endif /* CONFIG_SMP */
#endif /* ! defined(CONFIG_40x) */
	blr

/*
 * Flush MMU TLB for a particular address
 */
_GLOBAL(_tlbie)
#if defined(CONFIG_40x)
	/* We run the search with interrupts disabled because we have to change
	 * the PID and I don't want to preempt when that happens.
	 */
	mfmsr	r5
	mfspr	r6,SPRN_PID
	wrteei	0
	mtspr	SPRN_PID,r4
	tlbsx.	r3, 0, r3
	mtspr	SPRN_PID,r6
	wrtee	r5
	bne	10f
	sync
	/* There are only 64 TLB entries, so r3 < 64, which means bit 25 is clear.
	 * Since 25 is the V bit in the TLB_TAG, loading this value will invalidate
	 * the TLB entry. */
	tlbwe	r3, r3, TLB_TAG
	isync
10:

#elif defined(CONFIG_44x)
	mfspr	r5,SPRN_MMUCR
	rlwimi	r5,r4,0,24,31			/* Set TID */

	/* We have to run the search with interrupts disabled, even critical
	 * and debug interrupts (in fact the only critical exceptions we have
	 * are debug and machine check).  Otherwise  an interrupt which causes
	 * a TLB miss can clobber the MMUCR between the mtspr and the tlbsx. */
	mfmsr	r4
	lis	r6,(MSR_EE|MSR_CE|MSR_ME|MSR_DE)@ha
	addi	r6,r6,(MSR_EE|MSR_CE|MSR_ME|MSR_DE)@l
	andc	r6,r4,r6
	mtmsr	r6
	mtspr	SPRN_MMUCR,r5
	tlbsx.	r3, 0, r3
	mtmsr	r4
	bne	10f
	sync
	/* There are only 64 TLB entries, so r3 < 64,
	 * which means bit 22, is clear.  Since 22 is
	 * the V bit in the TLB_PAGEID, loading this
	 * value will invalidate the TLB entry.
	 */
	tlbwe	r3, r3, PPC44x_TLB_PAGEID
	isync
10:
#elif defined(CONFIG_FSL_BOOKE)
	rlwinm	r4, r3, 0, 0, 19
	ori	r5, r4, 0x08	/* TLBSEL = 1 */
	ori	r6, r4, 0x10	/* TLBSEL = 2 */
	ori	r7, r4, 0x18	/* TLBSEL = 3 */
	tlbivax	0, r4
	tlbivax	0, r5
	tlbivax	0, r6
	tlbivax	0, r7
	msync
#if defined(CONFIG_SMP)
	tlbsync
#endif /* CONFIG_SMP */
#else /* !(CONFIG_40x || CONFIG_44x || CONFIG_FSL_BOOKE) */
#if defined(CONFIG_SMP)
	rlwinm	r8,r1,0,0,18
	lwz	r8,TI_CPU(r8)
	oris	r8,r8,11
	mfmsr	r10
	SYNC
	rlwinm	r0,r10,0,17,15		/* clear bit 16 (MSR_EE) */
	rlwinm	r0,r0,0,28,26		/* clear DR */
	mtmsr	r0
	SYNC_601
	isync
	lis	r9,mmu_hash_lock@h
	ori	r9,r9,mmu_hash_lock@l
	tophys(r9,r9)
10:	lwarx	r7,0,r9
	cmpwi	0,r7,0
	bne-	10b
	stwcx.	r8,0,r9
	bne-	10b
	eieio
	tlbie	r3
	sync
	TLBSYNC
	li	r0,0
	stw	r0,0(r9)		/* clear mmu_hash_lock */
	mtmsr	r10
	SYNC_601
	isync
#else /* CONFIG_SMP */
	tlbie	r3
	sync
#endif /* CONFIG_SMP */
#endif /* ! CONFIG_40x */
	blr

/*
 * Flush instruction cache.
 * This is a no-op on the 601.
 */
_GLOBAL(flush_instruction_cache)
#if defined(CONFIG_8xx)
	isync
	lis	r5, IDC_INVALL@h
	mtspr	SPRN_IC_CST, r5
#elif defined(CONFIG_4xx)
#ifdef CONFIG_403GCX
	li      r3, 512
	mtctr   r3
	lis     r4, KERNELBASE@h
1:	iccci   0, r4
	addi    r4, r4, 16
	bdnz    1b
#else
	lis	r3, KERNELBASE@h
	iccci	0,r3
#endif
#elif CONFIG_FSL_BOOKE
BEGIN_FTR_SECTION
	mfspr   r3,SPRN_L1CSR0
	ori     r3,r3,L1CSR0_CFI|L1CSR0_CLFC
	/* msync; isync recommended here */
	mtspr   SPRN_L1CSR0,r3
	isync
	blr
END_FTR_SECTION_IFSET(CPU_FTR_UNIFIED_ID_CACHE)
	mfspr	r3,SPRN_L1CSR1
	ori	r3,r3,L1CSR1_ICFI|L1CSR1_ICLFR
	mtspr	SPRN_L1CSR1,r3
#else
	mfspr	r3,SPRN_PVR
	rlwinm	r3,r3,16,16,31
	cmpwi	0,r3,1
	beqlr			/* for 601, do nothing */
	/* 603/604 processor - use invalidate-all bit in HID0 */
	mfspr	r3,SPRN_HID0
	ori	r3,r3,HID0_ICFI
	mtspr	SPRN_HID0,r3
#endif /* CONFIG_8xx/4xx */
	isync
	blr

/*
 * Write any modified data cache blocks out to memory
 * and invalidate the corresponding instruction cache blocks.
 * This is a no-op on the 601.
 *
 * flush_icache_range(unsigned long start, unsigned long stop)
 */
_GLOBAL(__flush_icache_range)
BEGIN_FTR_SECTION
	blr				/* for 601, do nothing */
END_FTR_SECTION_IFSET(CPU_FTR_COHERENT_ICACHE)
	li	r5,L1_CACHE_BYTES-1
	andc	r3,r3,r5
	subf	r4,r3,r4
	add	r4,r4,r5
	srwi.	r4,r4,L1_CACHE_SHIFT
	beqlr
	mtctr	r4
	mr	r6,r3
1:	dcbst	0,r3
	addi	r3,r3,L1_CACHE_BYTES
	bdnz	1b
	sync				/* wait for dcbst's to get to ram */
	mtctr	r4
2:	icbi	0,r6
	addi	r6,r6,L1_CACHE_BYTES
	bdnz	2b
	sync				/* additional sync needed on g4 */
	isync
	blr
/*
 * Write any modified data cache blocks out to memory.
 * Does not invalidate the corresponding cache lines (especially for
 * any corresponding instruction cache).
 *
 * clean_dcache_range(unsigned long start, unsigned long stop)
 */
_GLOBAL(clean_dcache_range)
	li	r5,L1_CACHE_BYTES-1
	andc	r3,r3,r5
	subf	r4,r3,r4
	add	r4,r4,r5
	srwi.	r4,r4,L1_CACHE_SHIFT
	beqlr
	mtctr	r4

1:	dcbst	0,r3
	addi	r3,r3,L1_CACHE_BYTES
	bdnz	1b
	sync				/* wait for dcbst's to get to ram */
	blr

/*
 * Write any modified data cache blocks out to memory and invalidate them.
 * Does not invalidate the corresponding instruction cache blocks.
 *
 * flush_dcache_range(unsigned long start, unsigned long stop)
 */
_GLOBAL(flush_dcache_range)
	li	r5,L1_CACHE_BYTES-1
	andc	r3,r3,r5
	subf	r4,r3,r4
	add	r4,r4,r5
	srwi.	r4,r4,L1_CACHE_SHIFT
	beqlr
	mtctr	r4

1:	dcbf	0,r3
	addi	r3,r3,L1_CACHE_BYTES
	bdnz	1b
	sync				/* wait for dcbst's to get to ram */
	blr

/*
 * Like above, but invalidate the D-cache.  This is used by the 8xx
 * to invalidate the cache so the PPC core doesn't get stale data
 * from the CPM (no cache snooping here :-).
 *
 * invalidate_dcache_range(unsigned long start, unsigned long stop)
 */
_GLOBAL(invalidate_dcache_range)
	li	r5,L1_CACHE_BYTES-1
	andc	r3,r3,r5
	subf	r4,r3,r4
	add	r4,r4,r5
	srwi.	r4,r4,L1_CACHE_SHIFT
	beqlr
	mtctr	r4

1:	dcbi	0,r3
	addi	r3,r3,L1_CACHE_BYTES
	bdnz	1b
	sync				/* wait for dcbi's to get to ram */
	blr

/*
 * Flush a particular page from the data cache to RAM.
 * Note: this is necessary because the instruction cache does *not*
 * snoop from the data cache.
 * This is a no-op on the 601 which has a unified cache.
 *
 *	void __flush_dcache_icache(void *page)
 */
_GLOBAL(__flush_dcache_icache)
BEGIN_FTR_SECTION
	blr
END_FTR_SECTION_IFSET(CPU_FTR_COHERENT_ICACHE)
	rlwinm	r3,r3,0,0,19			/* Get page base address */
	li	r4,4096/L1_CACHE_BYTES	/* Number of lines in a page */
	mtctr	r4
	mr	r6,r3
0:	dcbst	0,r3				/* Write line to ram */
	addi	r3,r3,L1_CACHE_BYTES
	bdnz	0b
	sync
#ifndef CONFIG_44x
	/* We don't flush the icache on 44x. Those have a virtual icache
	 * and we don't have access to the virtual address here (it's
	 * not the page vaddr but where it's mapped in user space). The
	 * flushing of the icache on these is handled elsewhere, when
	 * a change in the address space occurs, before returning to
	 * user space
	 */
	mtctr	r4
1:	icbi	0,r6
	addi	r6,r6,L1_CACHE_BYTES
	bdnz	1b
	sync
	isync
#endif /* CONFIG_44x */
	blr

/*
 * Flush a particular page from the data cache to RAM, identified
 * by its physical address.  We turn off the MMU so we can just use
 * the physical address (this may be a highmem page without a kernel
 * mapping).
 *
 *	void __flush_dcache_icache_phys(unsigned long physaddr)
 */
_GLOBAL(__flush_dcache_icache_phys)
BEGIN_FTR_SECTION
	blr					/* for 601, do nothing */
END_FTR_SECTION_IFSET(CPU_FTR_COHERENT_ICACHE)
	mfmsr	r10
	rlwinm	r0,r10,0,28,26			/* clear DR */
	mtmsr	r0
	isync
	rlwinm	r3,r3,0,0,19			/* Get page base address */
	li	r4,4096/L1_CACHE_BYTES	/* Number of lines in a page */
	mtctr	r4
	mr	r6,r3
0:	dcbst	0,r3				/* Write line to ram */
	addi	r3,r3,L1_CACHE_BYTES
	bdnz	0b
	sync
	mtctr	r4
1:	icbi	0,r6
	addi	r6,r6,L1_CACHE_BYTES
	bdnz	1b
	sync
	mtmsr	r10				/* restore DR */
	isync
	blr

/*
 * Clear pages using the dcbz instruction, which doesn't cause any
 * memory traffic (except to write out any cache lines which get
 * displaced).  This only works on cacheable memory.
 *
 * void clear_pages(void *page, int order) ;
 */
_GLOBAL(clear_pages)
	li	r0,4096/L1_CACHE_BYTES
	slw	r0,r0,r4
	mtctr	r0
#ifdef CONFIG_8xx
	li	r4, 0
1:	stw	r4, 0(r3)
	stw	r4, 4(r3)
	stw	r4, 8(r3)
	stw	r4, 12(r3)
#else
1:	dcbz	0,r3
#endif
	addi	r3,r3,L1_CACHE_BYTES
	bdnz	1b
	blr

/*
 * Copy a whole page.  We use the dcbz instruction on the destination
 * to reduce memory traffic (it eliminates the unnecessary reads of
 * the destination into cache).  This requires that the destination
 * is cacheable.
 */
#define COPY_16_BYTES		\
	lwz	r6,4(r4);	\
	lwz	r7,8(r4);	\
	lwz	r8,12(r4);	\
	lwzu	r9,16(r4);	\
	stw	r6,4(r3);	\
	stw	r7,8(r3);	\
	stw	r8,12(r3);	\
	stwu	r9,16(r3)

_GLOBAL(copy_page)
	addi	r3,r3,-4
	addi	r4,r4,-4

#ifdef CONFIG_8xx
	/* don't use prefetch on 8xx */
    	li	r0,4096/L1_CACHE_BYTES
	mtctr	r0
1:	COPY_16_BYTES
	bdnz	1b
	blr

#else	/* not 8xx, we can prefetch */
	li	r5,4

#if MAX_COPY_PREFETCH > 1
	li	r0,MAX_COPY_PREFETCH
	li	r11,4
	mtctr	r0
11:	dcbt	r11,r4
	addi	r11,r11,L1_CACHE_BYTES
	bdnz	11b
#else /* MAX_COPY_PREFETCH == 1 */
	dcbt	r5,r4
	li	r11,L1_CACHE_BYTES+4
#endif /* MAX_COPY_PREFETCH */
	li	r0,4096/L1_CACHE_BYTES - MAX_COPY_PREFETCH
	crclr	4*cr0+eq
2:
	mtctr	r0
1:
	dcbt	r11,r4
	dcbz	r5,r3
	COPY_16_BYTES
#if L1_CACHE_BYTES >= 32
	COPY_16_BYTES
#if L1_CACHE_BYTES >= 64
	COPY_16_BYTES
	COPY_16_BYTES
#if L1_CACHE_BYTES >= 128
	COPY_16_BYTES
	COPY_16_BYTES
	COPY_16_BYTES
	COPY_16_BYTES
#endif
#endif
#endif
	bdnz	1b
	beqlr
	crnot	4*cr0+eq,4*cr0+eq
	li	r0,MAX_COPY_PREFETCH
	li	r11,4
	b	2b
#endif	/* CONFIG_8xx */

/*
 * void atomic_clear_mask(atomic_t mask, atomic_t *addr)
 * void atomic_set_mask(atomic_t mask, atomic_t *addr);
 */
_GLOBAL(atomic_clear_mask)
10:	lwarx	r5,0,r4
	andc	r5,r5,r3
	PPC405_ERR77(0,r4)
	stwcx.	r5,0,r4
	bne-	10b
	blr
_GLOBAL(atomic_set_mask)
10:	lwarx	r5,0,r4
	or	r5,r5,r3
	PPC405_ERR77(0,r4)
	stwcx.	r5,0,r4
	bne-	10b
	blr

/*
 * Extended precision shifts.
 *
 * Updated to be valid for shift counts from 0 to 63 inclusive.
 * -- Gabriel
 *
 * R3/R4 has 64 bit value
 * R5    has shift count
 * result in R3/R4
 *
 *  ashrdi3: arithmetic right shift (sign propagation)	
 *  lshrdi3: logical right shift
 *  ashldi3: left shift
 */
_GLOBAL(__ashrdi3)
	subfic	r6,r5,32
	srw	r4,r4,r5	# LSW = count > 31 ? 0 : LSW >> count
	addi	r7,r5,32	# could be xori, or addi with -32
	slw	r6,r3,r6	# t1 = count > 31 ? 0 : MSW << (32-count)
	rlwinm	r8,r7,0,32	# t3 = (count < 32) ? 32 : 0
	sraw	r7,r3,r7	# t2 = MSW >> (count-32)
	or	r4,r4,r6	# LSW |= t1
	slw	r7,r7,r8	# t2 = (count < 32) ? 0 : t2
	sraw	r3,r3,r5	# MSW = MSW >> count
	or	r4,r4,r7	# LSW |= t2
	blr

_GLOBAL(__ashldi3)
	subfic	r6,r5,32
	slw	r3,r3,r5	# MSW = count > 31 ? 0 : MSW << count
	addi	r7,r5,32	# could be xori, or addi with -32
	srw	r6,r4,r6	# t1 = count > 31 ? 0 : LSW >> (32-count)
	slw	r7,r4,r7	# t2 = count < 32 ? 0 : LSW << (count-32)
	or	r3,r3,r6	# MSW |= t1
	slw	r4,r4,r5	# LSW = LSW << count
	or	r3,r3,r7	# MSW |= t2
	blr

_GLOBAL(__lshrdi3)
	subfic	r6,r5,32
	srw	r4,r4,r5	# LSW = count > 31 ? 0 : LSW >> count
	addi	r7,r5,32	# could be xori, or addi with -32
	slw	r6,r3,r6	# t1 = count > 31 ? 0 : MSW << (32-count)
	srw	r7,r3,r7	# t2 = count < 32 ? 0 : MSW >> (count-32)
	or	r4,r4,r6	# LSW |= t1
	srw	r3,r3,r5	# MSW = MSW >> count
	or	r4,r4,r7	# LSW |= t2
	blr

_GLOBAL(abs)
	srawi	r4,r3,31
	xor	r3,r3,r4
	sub	r3,r3,r4
	blr

/*
 * Create a kernel thread
 *   kernel_thread(fn, arg, flags)
 */
_GLOBAL(kernel_thread)
	stwu	r1,-16(r1)
	stw	r30,8(r1)
	stw	r31,12(r1)
	mr	r30,r3		/* function */
	mr	r31,r4		/* argument */
	ori	r3,r5,CLONE_VM	/* flags */
	oris	r3,r3,CLONE_UNTRACED>>16
	li	r4,0		/* new sp (unused) */
	li	r0,__NR_clone
	sc
	cmpwi	0,r3,0		/* parent or child? */
	bne	1f		/* return if parent */
	li	r0,0		/* make top-level stack frame */
	stwu	r0,-16(r1)
	mtlr	r30		/* fn addr in lr */
	mr	r3,r31		/* load arg and call fn */
	PPC440EP_ERR42
	blrl
	li	r0,__NR_exit	/* exit if function returns */
	li	r3,0
	sc
1:	lwz	r30,8(r1)
	lwz	r31,12(r1)
	addi	r1,r1,16
	blr

_GLOBAL(kernel_execve)
	li	r0,__NR_execve
	sc
	bnslr
	neg	r3,r3
	blr

/*
 * This routine is just here to keep GCC happy - sigh...
 */
_GLOBAL(__main)
	blr

#ifdef CONFIG_KEXEC
	/*
	 * Must be relocatable PIC code callable as a C function.
	 */
	.globl relocate_new_kernel
relocate_new_kernel:
	/* r3 = page_list   */
	/* r4 = reboot_code_buffer */
	/* r5 = start_address      */

	li	r0, 0

	/*
	 * Set Machine Status Register to a known status,
	 * switch the MMU off and jump to 1: in a single step.
	 */

	mr	r8, r0
	ori     r8, r8, MSR_RI|MSR_ME
	mtspr	SPRN_SRR1, r8
	addi	r8, r4, 1f - relocate_new_kernel
	mtspr	SPRN_SRR0, r8
	sync
	rfi

1:
	/* from this point address translation is turned off */
	/* and interrupts are disabled */

	/* set a new stack at the bottom of our page... */
	/* (not really needed now) */
	addi	r1, r4, KEXEC_CONTROL_CODE_SIZE - 8 /* for LR Save+Back Chain */
	stw	r0, 0(r1)

	/* Do the copies */
	li	r6, 0 /* checksum */
	mr	r0, r3
	b	1f

0:	/* top, read another word for the indirection page */
	lwzu	r0, 4(r3)

1:
	/* is it a destination page? (r8) */
	rlwinm.	r7, r0, 0, 31, 31 /* IND_DESTINATION (1<<0) */
	beq	2f

	rlwinm	r8, r0, 0, 0, 19 /* clear kexec flags, page align */
	b	0b

2:	/* is it an indirection page? (r3) */
	rlwinm.	r7, r0, 0, 30, 30 /* IND_INDIRECTION (1<<1) */
	beq	2f

	rlwinm	r3, r0, 0, 0, 19 /* clear kexec flags, page align */
	subi	r3, r3, 4
	b	0b

2:	/* are we done? */
	rlwinm.	r7, r0, 0, 29, 29 /* IND_DONE (1<<2) */
	beq	2f
	b	3f

2:	/* is it a source page? (r9) */
	rlwinm.	r7, r0, 0, 28, 28 /* IND_SOURCE (1<<3) */
	beq	0b

	rlwinm	r9, r0, 0, 0, 19 /* clear kexec flags, page align */

	li	r7, PAGE_SIZE / 4
	mtctr   r7
	subi    r9, r9, 4
	subi    r8, r8, 4
9:
	lwzu    r0, 4(r9)  /* do the copy */
	xor	r6, r6, r0
	stwu    r0, 4(r8)
	dcbst	0, r8
	sync
	icbi	0, r8
	bdnz    9b

	addi    r9, r9, 4
	addi    r8, r8, 4
	b	0b

3:

	/* To be certain of avoiding problems with self-modifying code
	 * execute a serializing instruction here.
	 */
	isync
	sync

	/* jump to the entry point, usually the setup routine */
	mtlr	r5
	blrl

1:	b	1b

relocate_new_kernel_end:

	.globl relocate_new_kernel_size
relocate_new_kernel_size:
	.long relocate_new_kernel_end - relocate_new_kernel
#endif