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[POWERPC] Use 1TB segments
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This makes the kernel use 1TB segments for all kernel mappings and for
user addresses of 1TB and above, on machines which support them
(currently POWER5+, POWER6 and PA6T).

We detect that the machine supports 1TB segments by looking at the
ibm,processor-segment-sizes property in the device tree.

We don't currently use 1TB segments for user addresses < 1T, since
that would effectively prevent 32-bit processes from using huge pages
unless we also had a way to revert to using 256MB segments.  That
would be possible but would involve extra complications (such as
keeping track of which segment size was used when HPTEs were inserted)
and is not addressed here.

Parts of this patch were originally written by Ben Herrenschmidt.

Signed-off-by: Paul Mackerras <paulus@samba.org>
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Paul Mackerras committed Oct 12, 2007
1 parent 287e5d6 commit 1189be6
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Showing 23 changed files with 513 additions and 258 deletions.
14 changes: 13 additions & 1 deletion arch/powerpc/kernel/entry_64.S
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Original file line number Diff line number Diff line change
Expand Up @@ -372,9 +372,17 @@ END_FTR_SECTION_IFSET(CPU_FTR_ALTIVEC)
std r6,PACACURRENT(r13) /* Set new 'current' */

ld r8,KSP(r4) /* new stack pointer */
BEGIN_FTR_SECTION
b 2f
END_FTR_SECTION_IFCLR(CPU_FTR_SLB)
BEGIN_FTR_SECTION
clrrdi r6,r8,28 /* get its ESID */
clrrdi r9,r1,28 /* get current sp ESID */
END_FTR_SECTION_IFCLR(CPU_FTR_1T_SEGMENT)
BEGIN_FTR_SECTION
clrrdi r6,r8,40 /* get its 1T ESID */
clrrdi r9,r1,40 /* get current sp 1T ESID */
END_FTR_SECTION_IFSET(CPU_FTR_1T_SEGMENT)
clrldi. r0,r6,2 /* is new ESID c00000000? */
cmpd cr1,r6,r9 /* or is new ESID the same as current ESID? */
cror eq,4*cr1+eq,eq
Expand All @@ -384,6 +392,11 @@ BEGIN_FTR_SECTION
ld r7,KSP_VSID(r4) /* Get new stack's VSID */
oris r0,r6,(SLB_ESID_V)@h
ori r0,r0,(SLB_NUM_BOLTED-1)@l
BEGIN_FTR_SECTION
li r9,MMU_SEGSIZE_1T /* insert B field */
oris r6,r6,(MMU_SEGSIZE_1T << SLBIE_SSIZE_SHIFT)@h
rldimi r7,r9,SLB_VSID_SSIZE_SHIFT,0
END_FTR_SECTION_IFSET(CPU_FTR_1T_SEGMENT)

/* Update the last bolted SLB. No write barriers are needed
* here, provided we only update the current CPU's SLB shadow
Expand All @@ -401,7 +414,6 @@ BEGIN_FTR_SECTION
isync

2:
END_FTR_SECTION_IFSET(CPU_FTR_SLB)
clrrdi r7,r8,THREAD_SHIFT /* base of new stack */
/* Note: this uses SWITCH_FRAME_SIZE rather than INT_FRAME_SIZE
because we don't need to leave the 288-byte ABI gap at the
Expand Down
2 changes: 1 addition & 1 deletion arch/powerpc/kernel/head_64.S
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Original file line number Diff line number Diff line change
Expand Up @@ -935,7 +935,7 @@ _GLOBAL(do_stab_bolted)

/* Calculate VSID */
/* This is a kernel address, so protovsid = ESID */
ASM_VSID_SCRAMBLE(r11, r9)
ASM_VSID_SCRAMBLE(r11, r9, 256M)
rldic r9,r11,12,16 /* r9 = vsid << 12 */

/* Search the primary group for a free entry */
Expand Down
9 changes: 7 additions & 2 deletions arch/powerpc/kernel/process.c
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Original file line number Diff line number Diff line change
Expand Up @@ -564,10 +564,15 @@ int copy_thread(int nr, unsigned long clone_flags, unsigned long usp,

#ifdef CONFIG_PPC64
if (cpu_has_feature(CPU_FTR_SLB)) {
unsigned long sp_vsid = get_kernel_vsid(sp);
unsigned long sp_vsid;
unsigned long llp = mmu_psize_defs[mmu_linear_psize].sllp;

sp_vsid <<= SLB_VSID_SHIFT;
if (cpu_has_feature(CPU_FTR_1T_SEGMENT))
sp_vsid = get_kernel_vsid(sp, MMU_SEGSIZE_1T)
<< SLB_VSID_SHIFT_1T;
else
sp_vsid = get_kernel_vsid(sp, MMU_SEGSIZE_256M)
<< SLB_VSID_SHIFT;
sp_vsid |= SLB_VSID_KERNEL | llp;
p->thread.ksp_vsid = sp_vsid;
}
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73 changes: 65 additions & 8 deletions arch/powerpc/mm/hash_low_64.S
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Original file line number Diff line number Diff line change
Expand Up @@ -54,7 +54,7 @@

/*
* _hash_page_4K(unsigned long ea, unsigned long access, unsigned long vsid,
* pte_t *ptep, unsigned long trap, int local)
* 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
*/
Expand All @@ -66,6 +66,7 @@ _GLOBAL(__hash_page_4K)
/* 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
Expand Down Expand Up @@ -117,6 +118,10 @@ _GLOBAL(__hash_page_4K)
* 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
Expand All @@ -126,9 +131,20 @@ _GLOBAL(__hash_page_4K)
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 */
andi. r3,r30,0x1fe /* Get basic set of flags */
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) */
Expand Down Expand Up @@ -183,6 +199,7 @@ htab_insert_pte:
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
Expand All @@ -205,6 +222,7 @@ _GLOBAL(htab_call_hpte_insert1)
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
Expand Down Expand Up @@ -273,7 +291,8 @@ htab_modify_pte:
/* Call ppc_md.hpte_updatepp */
mr r5,r29 /* va */
li r6,MMU_PAGE_4K /* page size */
ld r7,STK_PARM(r8)(r1) /* get "local" param */
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() */

Expand Down Expand Up @@ -325,6 +344,7 @@ _GLOBAL(__hash_page_4K)
/* 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
Expand Down Expand Up @@ -383,18 +403,33 @@ _GLOBAL(__hash_page_4K)
/* 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
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 */
andi. r3,r30,0x1fe /* Get basic set of flags */
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) */
Expand Down Expand Up @@ -462,6 +497,7 @@ htab_special_pfn:
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
Expand All @@ -488,6 +524,7 @@ _GLOBAL(htab_call_hpte_insert1)
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
Expand Down Expand Up @@ -586,7 +623,8 @@ htab_modify_pte:
/* Call ppc_md.hpte_updatepp */
mr r5,r29 /* va */
li r6,MMU_PAGE_4K /* page size */
ld r7,STK_PARM(r8)(r1) /* get "local" param */
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() */

Expand Down Expand Up @@ -634,6 +672,7 @@ _GLOBAL(__hash_page_64K)
/* 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
Expand Down Expand Up @@ -690,6 +729,10 @@ END_FTR_SECTION_IFCLR(CPU_FTR_CI_LARGE_PAGE)
* 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
Expand All @@ -699,9 +742,20 @@ END_FTR_SECTION_IFCLR(CPU_FTR_CI_LARGE_PAGE)
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 */
andi. r3,r30,0x1fe /* Get basic set of flags */
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) */
Expand Down Expand Up @@ -756,6 +810,7 @@ ht64_insert_pte:
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
Expand All @@ -778,6 +833,7 @@ _GLOBAL(ht64_call_hpte_insert1)
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
Expand Down Expand Up @@ -846,7 +902,8 @@ ht64_modify_pte:
/* Call ppc_md.hpte_updatepp */
mr r5,r29 /* va */
li r6,MMU_PAGE_64K
ld r7,STK_PARM(r8)(r1) /* get "local" param */
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() */

Expand Down
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