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linux/arch/powerpc/mm/hash_low_64.S
Paul Mackerras 65ba6cdc83 [POWERPC] Clear sub-page HPTE present bits when demoting page size 
When we demote a slice from 64k to 4k, and we are about to insert an
HPTE for a 4k subpage and we notice that there is an existing 64k
HPTE, we first invalidate that HPTE before inserting the new 4k
subpage HPTE.  Since the bits that encode which hash bucket the old
HPTE was in overlap with the bits that encode which of the 16 subpages
have HPTEs, we need to clear out the subpage HPTE-present bits before
starting to insert HPTEs for the 4k subpages.  If we don't do that, we
can erroneously think that a subpage already has an HPTE when it
doesn't.

That in itself wouldn't be such a problem except that when we go to
update the HPTE that we think is present on machines with a
hypervisor, the hypervisor can tell us that the HPTE we think is there
is actually there even though it isn't, which can lead to a process
getting stuck in a loop, continually faulting.  The reason for the
confusion is that the AVPN (abbreviated virtual page number) we are
looking for in the HPTE for a 4k subpage can actually match the AVPN
in a stale HPTE for another 64k page.  For example, the HPTE for
the 4k subpage at 0x84000f000 will be in the same hash bucket and have
the same AVPN as the HPTE for the 64k page at 0x8400f0000.

This fixes the code to clear out the subpage HPTE-present bits.

Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-06-18 21:40:43 +10:00

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/*
* ppc64 MMU hashtable management routines
*
* (c) Copyright IBM Corp. 2003, 2005
*
* Maintained by: Benjamin Herrenschmidt
* <benh@kernel.crashing.org>
*
* This file is covered by the GNU Public Licence v2 as
* described in the kernel's COPYING file.
*/
#include <asm/reg.h>
#include <asm/pgtable.h>
#include <asm/mmu.h>
#include <asm/page.h>
#include <asm/types.h>
#include <asm/ppc_asm.h>
#include <asm/asm-offsets.h>
#include <asm/cputable.h>
.text
/*
* Stackframe:
*
* +-> Back chain (SP + 256)
* | General register save area (SP + 112)
* | Parameter save area (SP + 48)
* | TOC save area (SP + 40)
* | link editor doubleword (SP + 32)
* | compiler doubleword (SP + 24)
* | LR save area (SP + 16)
* | CR save area (SP + 8)
* SP ---> +-- Back chain (SP + 0)
*/
#define STACKFRAMESIZE 256
/* Save parameters offsets */
#define STK_PARM(i) (STACKFRAMESIZE + 48 + ((i)-3)*8)
/* Save non-volatile offsets */
#define STK_REG(i) (112 + ((i)-14)*8)
#ifndef CONFIG_PPC_64K_PAGES
/*****************************************************************************
* *
* 4K SW & 4K HW pages implementation *
* *
*****************************************************************************/
/*
* _hash_page_4K(unsigned long ea, unsigned long access, unsigned long vsid,
* pte_t *ptep, unsigned long trap, int local, int ssize)
*
* Adds a 4K page to the hash table in a segment of 4K pages only
*/
_GLOBAL(__hash_page_4K)
mflr r0
std r0,16(r1)
stdu r1,-STACKFRAMESIZE(r1)
/* Save all params that we need after a function call */
std r6,STK_PARM(r6)(r1)
std r8,STK_PARM(r8)(r1)
std r9,STK_PARM(r9)(r1)
/* Add _PAGE_PRESENT to access */
ori r4,r4,_PAGE_PRESENT
/* Save non-volatile registers.
* r31 will hold "old PTE"
* r30 is "new PTE"
* r29 is "va"
* r28 is a hash value
* r27 is hashtab mask (maybe dynamic patched instead ?)
*/
std r27,STK_REG(r27)(r1)
std r28,STK_REG(r28)(r1)
std r29,STK_REG(r29)(r1)
std r30,STK_REG(r30)(r1)
std r31,STK_REG(r31)(r1)
/* Step 1:
*
* Check permissions, atomically mark the linux PTE busy
* and hashed.
*/
1:
ldarx r31,0,r6
/* Check access rights (access & ~(pte_val(*ptep))) */
andc. r0,r4,r31
bne- htab_wrong_access
/* Check if PTE is busy */
andi. r0,r31,_PAGE_BUSY
/* If so, just bail out and refault if needed. Someone else
* is changing this PTE anyway and might hash it.
*/
bne- htab_bail_ok
/* Prepare new PTE value (turn access RW into DIRTY, then
* add BUSY,HASHPTE and ACCESSED)
*/
rlwinm r30,r4,32-9+7,31-7,31-7 /* _PAGE_RW -> _PAGE_DIRTY */
or r30,r30,r31
ori r30,r30,_PAGE_BUSY | _PAGE_ACCESSED | _PAGE_HASHPTE
/* Write the linux PTE atomically (setting busy) */
stdcx. r30,0,r6
bne- 1b
isync
/* Step 2:
*
* Insert/Update the HPTE in the hash table. At this point,
* r4 (access) is re-useable, we use it for the new HPTE flags
*/
BEGIN_FTR_SECTION
cmpdi r9,0 /* check segment size */
bne 3f
END_FTR_SECTION_IFSET(CPU_FTR_1T_SEGMENT)
/* Calc va and put it in r29 */
rldicr r29,r5,28,63-28
rldicl r3,r3,0,36
or r29,r3,r29
/* Calculate hash value for primary slot and store it in r28 */
rldicl r5,r5,0,25 /* vsid & 0x0000007fffffffff */
rldicl r0,r3,64-12,48 /* (ea >> 12) & 0xffff */
xor r28,r5,r0
b 4f
3: /* Calc VA and hash in r29 and r28 for 1T segment */
sldi r29,r5,40 /* vsid << 40 */
clrldi r3,r3,24 /* ea & 0xffffffffff */
rldic r28,r5,25,25 /* (vsid << 25) & 0x7fffffffff */
clrldi r5,r5,40 /* vsid & 0xffffff */
rldicl r0,r3,64-12,36 /* (ea >> 12) & 0xfffffff */
xor r28,r28,r5
or r29,r3,r29 /* VA */
xor r28,r28,r0 /* hash */
/* Convert linux PTE bits into HW equivalents */
4: andi. r3,r30,0x1fe /* Get basic set of flags */
xori r3,r3,HPTE_R_N /* _PAGE_EXEC -> NOEXEC */
rlwinm r0,r30,32-9+1,30,30 /* _PAGE_RW -> _PAGE_USER (r0) */
rlwinm r4,r30,32-7+1,30,30 /* _PAGE_DIRTY -> _PAGE_USER (r4) */
and r0,r0,r4 /* _PAGE_RW & _PAGE_DIRTY ->r0 bit 30*/
andc r0,r30,r0 /* r0 = pte & ~r0 */
rlwimi r3,r0,32-1,31,31 /* Insert result into PP lsb */
ori r3,r3,HPTE_R_C /* Always add "C" bit for perf. */
/* We eventually do the icache sync here (maybe inline that
* code rather than call a C function...)
*/
BEGIN_FTR_SECTION
mr r4,r30
mr r5,r7
bl .hash_page_do_lazy_icache
END_FTR_SECTION(CPU_FTR_NOEXECUTE|CPU_FTR_COHERENT_ICACHE, CPU_FTR_NOEXECUTE)
/* At this point, r3 contains new PP bits, save them in
* place of "access" in the param area (sic)
*/
std r3,STK_PARM(r4)(r1)
/* Get htab_hash_mask */
ld r4,htab_hash_mask@got(2)
ld r27,0(r4) /* htab_hash_mask -> r27 */
/* Check if we may already be in the hashtable, in this case, we
* go to out-of-line code to try to modify the HPTE
*/
andi. r0,r31,_PAGE_HASHPTE
bne htab_modify_pte
htab_insert_pte:
/* Clear hpte bits in new pte (we also clear BUSY btw) and
* add _PAGE_HASHPTE
*/
lis r0,_PAGE_HPTEFLAGS@h
ori r0,r0,_PAGE_HPTEFLAGS@l
andc r30,r30,r0
ori r30,r30,_PAGE_HASHPTE
/* physical address r5 */
rldicl r5,r31,64-PTE_RPN_SHIFT,PTE_RPN_SHIFT
sldi r5,r5,PAGE_SHIFT
/* Calculate primary group hash */
and r0,r28,r27
rldicr r3,r0,3,63-3 /* r3 = (hash & mask) << 3 */
/* Call ppc_md.hpte_insert */
ld r6,STK_PARM(r4)(r1) /* Retreive new pp bits */
mr r4,r29 /* Retreive va */
li r7,0 /* !bolted, !secondary */
li r8,MMU_PAGE_4K /* page size */
ld r9,STK_PARM(r9)(r1) /* segment size */
_GLOBAL(htab_call_hpte_insert1)
bl . /* Patched by htab_finish_init() */
cmpdi 0,r3,0
bge htab_pte_insert_ok /* Insertion successful */
cmpdi 0,r3,-2 /* Critical failure */
beq- htab_pte_insert_failure
/* Now try secondary slot */
/* physical address r5 */
rldicl r5,r31,64-PTE_RPN_SHIFT,PTE_RPN_SHIFT
sldi r5,r5,PAGE_SHIFT
/* Calculate secondary group hash */
andc r0,r27,r28
rldicr r3,r0,3,63-3 /* r0 = (~hash & mask) << 3 */
/* Call ppc_md.hpte_insert */
ld r6,STK_PARM(r4)(r1) /* Retreive new pp bits */
mr r4,r29 /* Retreive va */
li r7,HPTE_V_SECONDARY /* !bolted, secondary */
li r8,MMU_PAGE_4K /* page size */
ld r9,STK_PARM(r9)(r1) /* segment size */
_GLOBAL(htab_call_hpte_insert2)
bl . /* Patched by htab_finish_init() */
cmpdi 0,r3,0
bge+ htab_pte_insert_ok /* Insertion successful */
cmpdi 0,r3,-2 /* Critical failure */
beq- htab_pte_insert_failure
/* Both are full, we need to evict something */
mftb r0
/* Pick a random group based on TB */
andi. r0,r0,1
mr r5,r28
bne 2f
not r5,r5
2: and r0,r5,r27
rldicr r3,r0,3,63-3 /* r0 = (hash & mask) << 3 */
/* Call ppc_md.hpte_remove */
_GLOBAL(htab_call_hpte_remove)
bl . /* Patched by htab_finish_init() */
/* Try all again */
b htab_insert_pte
htab_bail_ok:
li r3,0
b htab_bail
htab_pte_insert_ok:
/* Insert slot number & secondary bit in PTE */
rldimi r30,r3,12,63-15
/* Write out the PTE with a normal write
* (maybe add eieio may be good still ?)
*/
htab_write_out_pte:
ld r6,STK_PARM(r6)(r1)
std r30,0(r6)
li r3, 0
htab_bail:
ld r27,STK_REG(r27)(r1)
ld r28,STK_REG(r28)(r1)
ld r29,STK_REG(r29)(r1)
ld r30,STK_REG(r30)(r1)
ld r31,STK_REG(r31)(r1)
addi r1,r1,STACKFRAMESIZE
ld r0,16(r1)
mtlr r0
blr
htab_modify_pte:
/* Keep PP bits in r4 and slot idx from the PTE around in r3 */
mr r4,r3
rlwinm r3,r31,32-12,29,31
/* Secondary group ? if yes, get a inverted hash value */
mr r5,r28
andi. r0,r31,_PAGE_SECONDARY
beq 1f
not r5,r5
1:
/* Calculate proper slot value for ppc_md.hpte_updatepp */
and r0,r5,r27
rldicr r0,r0,3,63-3 /* r0 = (hash & mask) << 3 */
add r3,r0,r3 /* add slot idx */
/* Call ppc_md.hpte_updatepp */
mr r5,r29 /* va */
li r6,MMU_PAGE_4K /* page size */
ld r7,STK_PARM(r9)(r1) /* segment size */
ld r8,STK_PARM(r8)(r1) /* get "local" param */
_GLOBAL(htab_call_hpte_updatepp)
bl . /* Patched by htab_finish_init() */
/* if we failed because typically the HPTE wasn't really here
* we try an insertion.
*/
cmpdi 0,r3,-1
beq- htab_insert_pte
/* Clear the BUSY bit and Write out the PTE */
li r0,_PAGE_BUSY
andc r30,r30,r0
b htab_write_out_pte
htab_wrong_access:
/* Bail out clearing reservation */
stdcx. r31,0,r6
li r3,1
b htab_bail
htab_pte_insert_failure:
/* Bail out restoring old PTE */
ld r6,STK_PARM(r6)(r1)
std r31,0(r6)
li r3,-1
b htab_bail
#else /* CONFIG_PPC_64K_PAGES */
/*****************************************************************************
* *
* 64K SW & 4K or 64K HW in a 4K segment pages implementation *
* *
*****************************************************************************/
/* _hash_page_4K(unsigned long ea, unsigned long access, unsigned long vsid,
* pte_t *ptep, unsigned long trap, int local, int ssize,
* int subpg_prot)
*/
/*
* For now, we do NOT implement Admixed pages
*/
_GLOBAL(__hash_page_4K)
mflr r0
std r0,16(r1)
stdu r1,-STACKFRAMESIZE(r1)
/* Save all params that we need after a function call */
std r6,STK_PARM(r6)(r1)
std r8,STK_PARM(r8)(r1)
std r9,STK_PARM(r9)(r1)
/* Add _PAGE_PRESENT to access */
ori r4,r4,_PAGE_PRESENT
/* Save non-volatile registers.
* r31 will hold "old PTE"
* r30 is "new PTE"
* r29 is "va"
* r28 is a hash value
* r27 is hashtab mask (maybe dynamic patched instead ?)
* r26 is the hidx mask
* r25 is the index in combo page
*/
std r25,STK_REG(r25)(r1)
std r26,STK_REG(r26)(r1)
std r27,STK_REG(r27)(r1)
std r28,STK_REG(r28)(r1)
std r29,STK_REG(r29)(r1)
std r30,STK_REG(r30)(r1)
std r31,STK_REG(r31)(r1)
/* Step 1:
*
* Check permissions, atomically mark the linux PTE busy
* and hashed.
*/
1:
ldarx r31,0,r6
/* Check access rights (access & ~(pte_val(*ptep))) */
andc. r0,r4,r31
bne- htab_wrong_access
/* Check if PTE is busy */
andi. r0,r31,_PAGE_BUSY
/* If so, just bail out and refault if needed. Someone else
* is changing this PTE anyway and might hash it.
*/
bne- htab_bail_ok
/* Prepare new PTE value (turn access RW into DIRTY, then
* add BUSY and ACCESSED)
*/
rlwinm r30,r4,32-9+7,31-7,31-7 /* _PAGE_RW -> _PAGE_DIRTY */
or r30,r30,r31
ori r30,r30,_PAGE_BUSY | _PAGE_ACCESSED | _PAGE_HASHPTE
oris r30,r30,_PAGE_COMBO@h
/* Write the linux PTE atomically (setting busy) */
stdcx. r30,0,r6
bne- 1b
isync
/* Step 2:
*
* Insert/Update the HPTE in the hash table. At this point,
* r4 (access) is re-useable, we use it for the new HPTE flags
*/
/* Load the hidx index */
rldicl r25,r3,64-12,60
BEGIN_FTR_SECTION
cmpdi r9,0 /* check segment size */
bne 3f
END_FTR_SECTION_IFSET(CPU_FTR_1T_SEGMENT)
/* Calc va and put it in r29 */
rldicr r29,r5,28,63-28 /* r29 = (vsid << 28) */
rldicl r3,r3,0,36 /* r3 = (ea & 0x0fffffff) */
or r29,r3,r29 /* r29 = va */
/* Calculate hash value for primary slot and store it in r28 */
rldicl r5,r5,0,25 /* vsid & 0x0000007fffffffff */
rldicl r0,r3,64-12,48 /* (ea >> 12) & 0xffff */
xor r28,r5,r0
b 4f
3: /* Calc VA and hash in r29 and r28 for 1T segment */
sldi r29,r5,40 /* vsid << 40 */
clrldi r3,r3,24 /* ea & 0xffffffffff */
rldic r28,r5,25,25 /* (vsid << 25) & 0x7fffffffff */
clrldi r5,r5,40 /* vsid & 0xffffff */
rldicl r0,r3,64-12,36 /* (ea >> 12) & 0xfffffff */
xor r28,r28,r5
or r29,r3,r29 /* VA */
xor r28,r28,r0 /* hash */
/* Convert linux PTE bits into HW equivalents */
4:
#ifdef CONFIG_PPC_SUBPAGE_PROT
andc r10,r30,r10
andi. r3,r10,0x1fe /* Get basic set of flags */
rlwinm r0,r10,32-9+1,30,30 /* _PAGE_RW -> _PAGE_USER (r0) */
#else
andi. r3,r30,0x1fe /* Get basic set of flags */
rlwinm r0,r30,32-9+1,30,30 /* _PAGE_RW -> _PAGE_USER (r0) */
#endif
xori r3,r3,HPTE_R_N /* _PAGE_EXEC -> NOEXEC */
rlwinm r4,r30,32-7+1,30,30 /* _PAGE_DIRTY -> _PAGE_USER (r4) */
and r0,r0,r4 /* _PAGE_RW & _PAGE_DIRTY ->r0 bit 30*/
andc r0,r3,r0 /* r0 = pte & ~r0 */
rlwimi r3,r0,32-1,31,31 /* Insert result into PP lsb */
ori r3,r3,HPTE_R_C /* Always add "C" bit for perf. */
/* We eventually do the icache sync here (maybe inline that
* code rather than call a C function...)
*/
BEGIN_FTR_SECTION
mr r4,r30
mr r5,r7
bl .hash_page_do_lazy_icache
END_FTR_SECTION(CPU_FTR_NOEXECUTE|CPU_FTR_COHERENT_ICACHE, CPU_FTR_NOEXECUTE)
/* At this point, r3 contains new PP bits, save them in
* place of "access" in the param area (sic)
*/
std r3,STK_PARM(r4)(r1)
/* Get htab_hash_mask */
ld r4,htab_hash_mask@got(2)
ld r27,0(r4) /* htab_hash_mask -> r27 */
/* Check if we may already be in the hashtable, in this case, we
* go to out-of-line code to try to modify the HPTE. We look for
* the bit at (1 >> (index + 32))
*/
andi. r0,r31,_PAGE_HASHPTE
li r26,0 /* Default hidx */
beq htab_insert_pte
/*
* Check if the pte was already inserted into the hash table
* as a 64k HW page, and invalidate the 64k HPTE if so.
*/
andis. r0,r31,_PAGE_COMBO@h
beq htab_inval_old_hpte
ld r6,STK_PARM(r6)(r1)
ori r26,r6,0x8000 /* Load the hidx mask */
ld r26,0(r26)
addi r5,r25,36 /* Check actual HPTE_SUB bit, this */
rldcr. r0,r31,r5,0 /* must match pgtable.h definition */
bne htab_modify_pte
htab_insert_pte:
/* real page number in r5, PTE RPN value + index */
andis. r0,r31,_PAGE_4K_PFN@h
srdi r5,r31,PTE_RPN_SHIFT
bne- htab_special_pfn
sldi r5,r5,PAGE_SHIFT-HW_PAGE_SHIFT
add r5,r5,r25
htab_special_pfn:
sldi r5,r5,HW_PAGE_SHIFT
/* Calculate primary group hash */
and r0,r28,r27
rldicr r3,r0,3,63-3 /* r0 = (hash & mask) << 3 */
/* Call ppc_md.hpte_insert */
ld r6,STK_PARM(r4)(r1) /* Retreive new pp bits */
mr r4,r29 /* Retreive va */
li r7,0 /* !bolted, !secondary */
li r8,MMU_PAGE_4K /* page size */
ld r9,STK_PARM(r9)(r1) /* segment size */
_GLOBAL(htab_call_hpte_insert1)
bl . /* patched by htab_finish_init() */
cmpdi 0,r3,0
bge htab_pte_insert_ok /* Insertion successful */
cmpdi 0,r3,-2 /* Critical failure */
beq- htab_pte_insert_failure
/* Now try secondary slot */
/* real page number in r5, PTE RPN value + index */
andis. r0,r31,_PAGE_4K_PFN@h
srdi r5,r31,PTE_RPN_SHIFT
bne- 3f
sldi r5,r5,PAGE_SHIFT-HW_PAGE_SHIFT
add r5,r5,r25
3: sldi r5,r5,HW_PAGE_SHIFT
/* Calculate secondary group hash */
andc r0,r27,r28
rldicr r3,r0,3,63-3 /* r0 = (~hash & mask) << 3 */
/* Call ppc_md.hpte_insert */
ld r6,STK_PARM(r4)(r1) /* Retreive new pp bits */
mr r4,r29 /* Retreive va */
li r7,HPTE_V_SECONDARY /* !bolted, secondary */
li r8,MMU_PAGE_4K /* page size */
ld r9,STK_PARM(r9)(r1) /* segment size */
_GLOBAL(htab_call_hpte_insert2)
bl . /* patched by htab_finish_init() */
cmpdi 0,r3,0
bge+ htab_pte_insert_ok /* Insertion successful */
cmpdi 0,r3,-2 /* Critical failure */
beq- htab_pte_insert_failure
/* Both are full, we need to evict something */
mftb r0
/* Pick a random group based on TB */
andi. r0,r0,1
mr r5,r28
bne 2f
not r5,r5
2: and r0,r5,r27
rldicr r3,r0,3,63-3 /* r0 = (hash & mask) << 3 */
/* Call ppc_md.hpte_remove */
_GLOBAL(htab_call_hpte_remove)
bl . /* patched by htab_finish_init() */
/* Try all again */
b htab_insert_pte
/*
* Call out to C code to invalidate an 64k HW HPTE that is
* useless now that the segment has been switched to 4k pages.
*/
htab_inval_old_hpte:
mr r3,r29 /* virtual addr */
mr r4,r31 /* PTE.pte */
li r5,0 /* PTE.hidx */
li r6,MMU_PAGE_64K /* psize */
ld r7,STK_PARM(r9)(r1) /* ssize */
ld r8,STK_PARM(r8)(r1) /* local */
bl .flush_hash_page
/* Clear out _PAGE_HPTE_SUB bits in the new linux PTE */
lis r0,_PAGE_HPTE_SUB@h
ori r0,r0,_PAGE_HPTE_SUB@l
andc r30,r30,r0
b htab_insert_pte
htab_bail_ok:
li r3,0
b htab_bail
htab_pte_insert_ok:
/* Insert slot number & secondary bit in PTE second half,
* clear _PAGE_BUSY and set approriate HPTE slot bit
*/
ld r6,STK_PARM(r6)(r1)
li r0,_PAGE_BUSY
andc r30,r30,r0
/* HPTE SUB bit */
li r0,1
subfic r5,r25,27 /* Must match bit position in */
sld r0,r0,r5 /* pgtable.h */
or r30,r30,r0
/* hindx */
sldi r5,r25,2
sld r3,r3,r5
li r4,0xf
sld r4,r4,r5
andc r26,r26,r4
or r26,r26,r3
ori r5,r6,0x8000
std r26,0(r5)
lwsync
std r30,0(r6)
li r3, 0
htab_bail:
ld r25,STK_REG(r25)(r1)
ld r26,STK_REG(r26)(r1)
ld r27,STK_REG(r27)(r1)
ld r28,STK_REG(r28)(r1)
ld r29,STK_REG(r29)(r1)
ld r30,STK_REG(r30)(r1)
ld r31,STK_REG(r31)(r1)
addi r1,r1,STACKFRAMESIZE
ld r0,16(r1)
mtlr r0
blr
htab_modify_pte:
/* Keep PP bits in r4 and slot idx from the PTE around in r3 */
mr r4,r3
sldi r5,r25,2
srd r3,r26,r5
/* Secondary group ? if yes, get a inverted hash value */
mr r5,r28
andi. r0,r3,0x8 /* page secondary ? */
beq 1f
not r5,r5
1: andi. r3,r3,0x7 /* extract idx alone */
/* Calculate proper slot value for ppc_md.hpte_updatepp */
and r0,r5,r27
rldicr r0,r0,3,63-3 /* r0 = (hash & mask) << 3 */
add r3,r0,r3 /* add slot idx */
/* Call ppc_md.hpte_updatepp */
mr r5,r29 /* va */
li r6,MMU_PAGE_4K /* page size */
ld r7,STK_PARM(r9)(r1) /* segment size */
ld r8,STK_PARM(r8)(r1) /* get "local" param */
_GLOBAL(htab_call_hpte_updatepp)
bl . /* patched by htab_finish_init() */
/* if we failed because typically the HPTE wasn't really here
* we try an insertion.
*/
cmpdi 0,r3,-1
beq- htab_insert_pte
/* Clear the BUSY bit and Write out the PTE */
li r0,_PAGE_BUSY
andc r30,r30,r0
ld r6,STK_PARM(r6)(r1)
std r30,0(r6)
li r3,0
b htab_bail
htab_wrong_access:
/* Bail out clearing reservation */
stdcx. r31,0,r6
li r3,1
b htab_bail
htab_pte_insert_failure:
/* Bail out restoring old PTE */
ld r6,STK_PARM(r6)(r1)
std r31,0(r6)
li r3,-1
b htab_bail
#endif /* CONFIG_PPC_64K_PAGES */
#ifdef CONFIG_PPC_HAS_HASH_64K
/*****************************************************************************
* *
* 64K SW & 64K HW in a 64K segment pages implementation *
* *
*****************************************************************************/
_GLOBAL(__hash_page_64K)
mflr r0
std r0,16(r1)
stdu r1,-STACKFRAMESIZE(r1)
/* Save all params that we need after a function call */
std r6,STK_PARM(r6)(r1)
std r8,STK_PARM(r8)(r1)
std r9,STK_PARM(r9)(r1)
/* Add _PAGE_PRESENT to access */
ori r4,r4,_PAGE_PRESENT
/* Save non-volatile registers.
* r31 will hold "old PTE"
* r30 is "new PTE"
* r29 is "va"
* r28 is a hash value
* r27 is hashtab mask (maybe dynamic patched instead ?)
*/
std r27,STK_REG(r27)(r1)
std r28,STK_REG(r28)(r1)
std r29,STK_REG(r29)(r1)
std r30,STK_REG(r30)(r1)
std r31,STK_REG(r31)(r1)
/* Step 1:
*
* Check permissions, atomically mark the linux PTE busy
* and hashed.
*/
1:
ldarx r31,0,r6
/* Check access rights (access & ~(pte_val(*ptep))) */
andc. r0,r4,r31
bne- ht64_wrong_access
/* Check if PTE is busy */
andi. r0,r31,_PAGE_BUSY
/* If so, just bail out and refault if needed. Someone else
* is changing this PTE anyway and might hash it.
*/
bne- ht64_bail_ok
BEGIN_FTR_SECTION
/* Check if PTE has the cache-inhibit bit set */
andi. r0,r31,_PAGE_NO_CACHE
/* If so, bail out and refault as a 4k page */
bne- ht64_bail_ok
END_FTR_SECTION_IFCLR(CPU_FTR_CI_LARGE_PAGE)
/* Prepare new PTE value (turn access RW into DIRTY, then
* add BUSY,HASHPTE and ACCESSED)
*/
rlwinm r30,r4,32-9+7,31-7,31-7 /* _PAGE_RW -> _PAGE_DIRTY */
or r30,r30,r31
ori r30,r30,_PAGE_BUSY | _PAGE_ACCESSED | _PAGE_HASHPTE
/* Write the linux PTE atomically (setting busy) */
stdcx. r30,0,r6
bne- 1b
isync
/* Step 2:
*
* Insert/Update the HPTE in the hash table. At this point,
* r4 (access) is re-useable, we use it for the new HPTE flags
*/
BEGIN_FTR_SECTION
cmpdi r9,0 /* check segment size */
bne 3f
END_FTR_SECTION_IFSET(CPU_FTR_1T_SEGMENT)
/* Calc va and put it in r29 */
rldicr r29,r5,28,63-28
rldicl r3,r3,0,36
or r29,r3,r29
/* Calculate hash value for primary slot and store it in r28 */
rldicl r5,r5,0,25 /* vsid & 0x0000007fffffffff */
rldicl r0,r3,64-16,52 /* (ea >> 16) & 0xfff */
xor r28,r5,r0
b 4f
3: /* Calc VA and hash in r29 and r28 for 1T segment */
sldi r29,r5,40 /* vsid << 40 */
clrldi r3,r3,24 /* ea & 0xffffffffff */
rldic r28,r5,25,25 /* (vsid << 25) & 0x7fffffffff */
clrldi r5,r5,40 /* vsid & 0xffffff */
rldicl r0,r3,64-16,40 /* (ea >> 16) & 0xffffff */
xor r28,r28,r5
or r29,r3,r29 /* VA */
xor r28,r28,r0 /* hash */
/* Convert linux PTE bits into HW equivalents */
4: andi. r3,r30,0x1fe /* Get basic set of flags */
xori r3,r3,HPTE_R_N /* _PAGE_EXEC -> NOEXEC */
rlwinm r0,r30,32-9+1,30,30 /* _PAGE_RW -> _PAGE_USER (r0) */
rlwinm r4,r30,32-7+1,30,30 /* _PAGE_DIRTY -> _PAGE_USER (r4) */
and r0,r0,r4 /* _PAGE_RW & _PAGE_DIRTY ->r0 bit 30*/
andc r0,r30,r0 /* r0 = pte & ~r0 */
rlwimi r3,r0,32-1,31,31 /* Insert result into PP lsb */
ori r3,r3,HPTE_R_C /* Always add "C" bit for perf. */
/* We eventually do the icache sync here (maybe inline that
* code rather than call a C function...)
*/
BEGIN_FTR_SECTION
mr r4,r30
mr r5,r7
bl .hash_page_do_lazy_icache
END_FTR_SECTION(CPU_FTR_NOEXECUTE|CPU_FTR_COHERENT_ICACHE, CPU_FTR_NOEXECUTE)
/* At this point, r3 contains new PP bits, save them in
* place of "access" in the param area (sic)
*/
std r3,STK_PARM(r4)(r1)
/* Get htab_hash_mask */
ld r4,htab_hash_mask@got(2)
ld r27,0(r4) /* htab_hash_mask -> r27 */
/* Check if we may already be in the hashtable, in this case, we
* go to out-of-line code to try to modify the HPTE
*/
andi. r0,r31,_PAGE_HASHPTE
bne ht64_modify_pte
ht64_insert_pte:
/* Clear hpte bits in new pte (we also clear BUSY btw) and
* add _PAGE_HASHPTE
*/
lis r0,_PAGE_HPTEFLAGS@h
ori r0,r0,_PAGE_HPTEFLAGS@l
andc r30,r30,r0
ori r30,r30,_PAGE_HASHPTE
/* Phyical address in r5 */
rldicl r5,r31,64-PTE_RPN_SHIFT,PTE_RPN_SHIFT
sldi r5,r5,PAGE_SHIFT
/* Calculate primary group hash */
and r0,r28,r27
rldicr r3,r0,3,63-3 /* r0 = (hash & mask) << 3 */
/* Call ppc_md.hpte_insert */
ld r6,STK_PARM(r4)(r1) /* Retreive new pp bits */
mr r4,r29 /* Retreive va */
li r7,0 /* !bolted, !secondary */
li r8,MMU_PAGE_64K
ld r9,STK_PARM(r9)(r1) /* segment size */
_GLOBAL(ht64_call_hpte_insert1)
bl . /* patched by htab_finish_init() */
cmpdi 0,r3,0
bge ht64_pte_insert_ok /* Insertion successful */
cmpdi 0,r3,-2 /* Critical failure */
beq- ht64_pte_insert_failure
/* Now try secondary slot */
/* Phyical address in r5 */
rldicl r5,r31,64-PTE_RPN_SHIFT,PTE_RPN_SHIFT
sldi r5,r5,PAGE_SHIFT
/* Calculate secondary group hash */
andc r0,r27,r28
rldicr r3,r0,3,63-3 /* r0 = (~hash & mask) << 3 */
/* Call ppc_md.hpte_insert */
ld r6,STK_PARM(r4)(r1) /* Retreive new pp bits */
mr r4,r29 /* Retreive va */
li r7,HPTE_V_SECONDARY /* !bolted, secondary */
li r8,MMU_PAGE_64K
ld r9,STK_PARM(r9)(r1) /* segment size */
_GLOBAL(ht64_call_hpte_insert2)
bl . /* patched by htab_finish_init() */
cmpdi 0,r3,0
bge+ ht64_pte_insert_ok /* Insertion successful */
cmpdi 0,r3,-2 /* Critical failure */
beq- ht64_pte_insert_failure
/* Both are full, we need to evict something */
mftb r0
/* Pick a random group based on TB */
andi. r0,r0,1
mr r5,r28
bne 2f
not r5,r5
2: and r0,r5,r27
rldicr r3,r0,3,63-3 /* r0 = (hash & mask) << 3 */
/* Call ppc_md.hpte_remove */
_GLOBAL(ht64_call_hpte_remove)
bl . /* patched by htab_finish_init() */
/* Try all again */
b ht64_insert_pte
ht64_bail_ok:
li r3,0
b ht64_bail
ht64_pte_insert_ok:
/* Insert slot number & secondary bit in PTE */
rldimi r30,r3,12,63-15
/* Write out the PTE with a normal write
* (maybe add eieio may be good still ?)
*/
ht64_write_out_pte:
ld r6,STK_PARM(r6)(r1)
std r30,0(r6)
li r3, 0
ht64_bail:
ld r27,STK_REG(r27)(r1)
ld r28,STK_REG(r28)(r1)
ld r29,STK_REG(r29)(r1)
ld r30,STK_REG(r30)(r1)
ld r31,STK_REG(r31)(r1)
addi r1,r1,STACKFRAMESIZE
ld r0,16(r1)
mtlr r0
blr
ht64_modify_pte:
/* Keep PP bits in r4 and slot idx from the PTE around in r3 */
mr r4,r3
rlwinm r3,r31,32-12,29,31
/* Secondary group ? if yes, get a inverted hash value */
mr r5,r28
andi. r0,r31,_PAGE_F_SECOND
beq 1f
not r5,r5
1:
/* Calculate proper slot value for ppc_md.hpte_updatepp */
and r0,r5,r27
rldicr r0,r0,3,63-3 /* r0 = (hash & mask) << 3 */
add r3,r0,r3 /* add slot idx */
/* Call ppc_md.hpte_updatepp */
mr r5,r29 /* va */
li r6,MMU_PAGE_64K
ld r7,STK_PARM(r9)(r1) /* segment size */
ld r8,STK_PARM(r8)(r1) /* get "local" param */
_GLOBAL(ht64_call_hpte_updatepp)
bl . /* patched by htab_finish_init() */
/* if we failed because typically the HPTE wasn't really here
* we try an insertion.
*/
cmpdi 0,r3,-1
beq- ht64_insert_pte
/* Clear the BUSY bit and Write out the PTE */
li r0,_PAGE_BUSY
andc r30,r30,r0
b ht64_write_out_pte
ht64_wrong_access:
/* Bail out clearing reservation */
stdcx. r31,0,r6
li r3,1
b ht64_bail
ht64_pte_insert_failure:
/* Bail out restoring old PTE */
ld r6,STK_PARM(r6)(r1)
std r31,0(r6)
li r3,-1
b ht64_bail
#endif /* CONFIG_PPC_HAS_HASH_64K */
/*****************************************************************************
* *
* Huge pages implementation is in hugetlbpage.c *
* *
*****************************************************************************/
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