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slb_low.S
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/*
* arch/ppc64/mm/slb_low.S
*
* Low-level SLB routines
*
* Copyright (C) 2004 David Gibson <[email protected]>, IBM
*
* Based on earlier C version:
* Dave Engebretsen and Mike Corrigan {engebret|mikejc}@us.ibm.com
* Copyright (c) 2001 Dave Engebretsen
* Copyright (C) 2002 Anton Blanchard <[email protected]>, IBM
*
* 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/config.h>
#include <asm/processor.h>
#include <asm/page.h>
#include <asm/mmu.h>
#include <asm/ppc_asm.h>
#include <asm/offsets.h>
#include <asm/cputable.h>
/* void slb_allocate(unsigned long ea);
*
* Create an SLB entry for the given EA (user or kernel).
* r3 = faulting address, r13 = PACA
* r9, r10, r11 are clobbered by this function
* No other registers are examined or changed.
*/
_GLOBAL(slb_allocate)
/*
* First find a slot, round robin. Previously we tried to find
* a free slot first but that took too long. Unfortunately we
* dont have any LRU information to help us choose a slot.
*/
#ifdef CONFIG_PPC_ISERIES
/*
* On iSeries, the "bolted" stack segment can be cast out on
* shared processor switch so we need to check for a miss on
* it and restore it to the right slot.
*/
ld r9,PACAKSAVE(r13)
clrrdi r9,r9,28
clrrdi r11,r3,28
li r10,SLB_NUM_BOLTED-1 /* Stack goes in last bolted slot */
cmpld r9,r11
beq 3f
#endif /* CONFIG_PPC_ISERIES */
ld r10,PACASTABRR(r13)
addi r10,r10,1
/* use a cpu feature mask if we ever change our slb size */
cmpldi r10,SLB_NUM_ENTRIES
blt+ 4f
li r10,SLB_NUM_BOLTED
4:
std r10,PACASTABRR(r13)
3:
/* r3 = faulting address, r10 = entry */
srdi r9,r3,60 /* get region */
srdi r3,r3,28 /* get esid */
cmpldi cr7,r9,0xc /* cmp KERNELBASE for later use */
rldimi r10,r3,28,0 /* r10= ESID<<28 | entry */
oris r10,r10,SLB_ESID_V@h /* r10 |= SLB_ESID_V */
/* r3 = esid, r10 = esid_data, cr7 = <>KERNELBASE */
blt cr7,0f /* user or kernel? */
/* kernel address: proto-VSID = ESID */
/* WARNING - MAGIC: we don't use the VSID 0xfffffffff, but
* this code will generate the protoVSID 0xfffffffff for the
* top segment. That's ok, the scramble below will translate
* it to VSID 0, which is reserved as a bad VSID - one which
* will never have any pages in it. */
li r11,SLB_VSID_KERNEL
BEGIN_FTR_SECTION
bne cr7,9f
li r11,(SLB_VSID_KERNEL|SLB_VSID_L)
END_FTR_SECTION_IFSET(CPU_FTR_16M_PAGE)
b 9f
0: /* user address: proto-VSID = context<<15 | ESID */
srdi. r9,r3,USER_ESID_BITS
bne- 8f /* invalid ea bits set */
#ifdef CONFIG_HUGETLB_PAGE
BEGIN_FTR_SECTION
lhz r9,PACAHIGHHTLBAREAS(r13)
srdi r11,r3,(HTLB_AREA_SHIFT-SID_SHIFT)
srd r9,r9,r11
lhz r11,PACALOWHTLBAREAS(r13)
srd r11,r11,r3
or r9,r9,r11
END_FTR_SECTION_IFSET(CPU_FTR_16M_PAGE)
#endif /* CONFIG_HUGETLB_PAGE */
li r11,SLB_VSID_USER
#ifdef CONFIG_HUGETLB_PAGE
BEGIN_FTR_SECTION
rldimi r11,r9,8,55 /* shift masked bit into SLB_VSID_L */
END_FTR_SECTION_IFSET(CPU_FTR_16M_PAGE)
#endif /* CONFIG_HUGETLB_PAGE */
ld r9,PACACONTEXTID(r13)
rldimi r3,r9,USER_ESID_BITS,0
9: /* r3 = protovsid, r11 = flags, r10 = esid_data, cr7 = <>KERNELBASE */
ASM_VSID_SCRAMBLE(r3,r9)
rldimi r11,r3,SLB_VSID_SHIFT,16 /* combine VSID and flags */
/*
* No need for an isync before or after this slbmte. The exception
* we enter with and the rfid we exit with are context synchronizing.
*/
slbmte r11,r10
bgelr cr7 /* we're done for kernel addresses */
/* Update the slb cache */
lhz r3,PACASLBCACHEPTR(r13) /* offset = paca->slb_cache_ptr */
cmpldi r3,SLB_CACHE_ENTRIES
bge 1f
/* still room in the slb cache */
sldi r11,r3,1 /* r11 = offset * sizeof(u16) */
rldicl r10,r10,36,28 /* get low 16 bits of the ESID */
add r11,r11,r13 /* r11 = (u16 *)paca + offset */
sth r10,PACASLBCACHE(r11) /* paca->slb_cache[offset] = esid */
addi r3,r3,1 /* offset++ */
b 2f
1: /* offset >= SLB_CACHE_ENTRIES */
li r3,SLB_CACHE_ENTRIES+1
2:
sth r3,PACASLBCACHEPTR(r13) /* paca->slb_cache_ptr = offset */
blr
8: /* invalid EA */
li r3,0 /* BAD_VSID */
li r11,SLB_VSID_USER /* flags don't much matter */
b 9b