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linux-pinenote/arch/powerpc/platforms/iseries/exception.S
Michael Ellerman 1426d5a3bd powerpc: Dynamically allocate pacas 
On 64-bit kernels we currently have a 512 byte struct paca_struct for
each cpu (usually just called "the paca"). Currently they are statically
allocated, which means a kernel built for a large number of cpus will
waste a lot of space if it's booted on a machine with few cpus.

We can avoid that by only allocating the number of pacas we need at
boot. However this is complicated by the fact that we need to access
the paca before we know how many cpus there are in the system.

The solution is to dynamically allocate enough space for NR_CPUS pacas,
but then later in boot when we know how many cpus we have, we free any
unused pacas.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2010-03-09 11:52:52 +11:00

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/*
* Low level routines for legacy iSeries support.
*
* Extracted from head_64.S
*
* PowerPC version
* Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
*
* Rewritten by Cort Dougan (cort@cs.nmt.edu) for PReP
* Copyright (C) 1996 Cort Dougan <cort@cs.nmt.edu>
* Adapted for Power Macintosh by Paul Mackerras.
* Low-level exception handlers and MMU support
* rewritten by Paul Mackerras.
* Copyright (C) 1996 Paul Mackerras.
*
* Adapted for 64bit PowerPC by Dave Engebretsen, Peter Bergner, and
* Mike Corrigan {engebret|bergner|mikejc}@us.ibm.com
*
* This file contains the low-level support and setup for the
* PowerPC-64 platform, including trap and interrupt dispatch.
*
* 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 <asm/reg.h>
#include <asm/ppc_asm.h>
#include <asm/asm-offsets.h>
#include <asm/thread_info.h>
#include <asm/ptrace.h>
#include <asm/cputable.h>
#include "exception.h"
.text
.globl system_reset_iSeries
system_reset_iSeries:
bl .relative_toc
mfspr r13,SPRN_SPRG3 /* Get alpaca address */
LOAD_REG_ADDR(r23, alpaca)
li r0,ALPACA_SIZE
sub r23,r13,r23
divdu r24,r23,r0 /* r24 has cpu number */
cmpwi 0,r24,0 /* Are we processor 0? */
bne 1f
LOAD_REG_ADDR(r13, boot_paca)
mtspr SPRN_SPRG_PACA,r13 /* Save it away for the future */
mfmsr r23
ori r23,r23,MSR_RI
mtmsrd r23 /* RI on */
b .__start_initialization_iSeries /* Start up the first processor */
1: mfspr r4,SPRN_CTRLF
li r5,CTRL_RUNLATCH /* Turn off the run light */
andc r4,r4,r5
mtspr SPRN_CTRLT,r4
/* Spin on __secondary_hold_spinloop until it is updated by the boot cpu. */
/* In the UP case we'll yield() later, and we will not access the paca anyway */
#ifdef CONFIG_SMP
1:
HMT_LOW
LOAD_REG_ADDR(r23, __secondary_hold_spinloop)
ld r23,0(r23)
sync
LOAD_REG_ADDR(r3,current_set)
sldi r28,r24,3 /* get current_set[cpu#] */
ldx r3,r3,r28
addi r1,r3,THREAD_SIZE
subi r1,r1,STACK_FRAME_OVERHEAD
cmpwi 0,r23,0 /* Keep poking the Hypervisor until */
bne 2f /* we're released */
/* Let the Hypervisor know we are alive */
/* 8002 is a call to HvCallCfg::getLps, a harmless Hypervisor function */
lis r3,0x8002
rldicr r3,r3,32,15 /* r0 = (r3 << 32) & 0xffff000000000000 */
li r0,-1 /* r0=-1 indicates a Hypervisor call */
sc /* Invoke the hypervisor via a system call */
b 1b
#endif
2:
/* Load our paca now that it's been allocated */
LOAD_REG_ADDR(r13, paca)
ld r13,0(r13)
mulli r0,r24,PACA_SIZE
add r13,r13,r0
mtspr SPRN_SPRG_PACA,r13 /* Save it away for the future */
mfmsr r23
ori r23,r23,MSR_RI
mtmsrd r23 /* RI on */
HMT_LOW
#ifdef CONFIG_SMP
lbz r23,PACAPROCSTART(r13) /* Test if this processor
* should start */
sync
LOAD_REG_ADDR(r3,current_set)
sldi r28,r24,3 /* get current_set[cpu#] */
ldx r3,r3,r28
addi r1,r3,THREAD_SIZE
subi r1,r1,STACK_FRAME_OVERHEAD
cmpwi 0,r23,0
beq iSeries_secondary_smp_loop /* Loop until told to go */
b __secondary_start /* Loop until told to go */
iSeries_secondary_smp_loop:
/* Let the Hypervisor know we are alive */
/* 8002 is a call to HvCallCfg::getLps, a harmless Hypervisor function */
lis r3,0x8002
rldicr r3,r3,32,15 /* r0 = (r3 << 32) & 0xffff000000000000 */
#else /* CONFIG_SMP */
/* Yield the processor. This is required for non-SMP kernels
which are running on multi-threaded machines. */
lis r3,0x8000
rldicr r3,r3,32,15 /* r3 = (r3 << 32) & 0xffff000000000000 */
addi r3,r3,18 /* r3 = 0x8000000000000012 which is "yield" */
li r4,0 /* "yield timed" */
li r5,-1 /* "yield forever" */
#endif /* CONFIG_SMP */
li r0,-1 /* r0=-1 indicates a Hypervisor call */
sc /* Invoke the hypervisor via a system call */
mfspr r13,SPRN_SPRG_PACA /* Put r13 back ???? */
b 2b /* If SMP not configured, secondaries
* loop forever */
/*** ISeries-LPAR interrupt handlers ***/
STD_EXCEPTION_ISERIES(machine_check, PACA_EXMC)
.globl data_access_iSeries
data_access_iSeries:
mtspr SPRN_SPRG_SCRATCH0,r13
BEGIN_FTR_SECTION
mfspr r13,SPRN_SPRG_PACA
std r9,PACA_EXSLB+EX_R9(r13)
std r10,PACA_EXSLB+EX_R10(r13)
mfspr r10,SPRN_DAR
mfspr r9,SPRN_DSISR
srdi r10,r10,60
rlwimi r10,r9,16,0x20
mfcr r9
cmpwi r10,0x2c
beq .do_stab_bolted_iSeries
ld r10,PACA_EXSLB+EX_R10(r13)
std r11,PACA_EXGEN+EX_R11(r13)
ld r11,PACA_EXSLB+EX_R9(r13)
std r12,PACA_EXGEN+EX_R12(r13)
mfspr r12,SPRN_SPRG_SCRATCH0
std r10,PACA_EXGEN+EX_R10(r13)
std r11,PACA_EXGEN+EX_R9(r13)
std r12,PACA_EXGEN+EX_R13(r13)
EXCEPTION_PROLOG_ISERIES_1
FTR_SECTION_ELSE
EXCEPTION_PROLOG_1(PACA_EXGEN)
EXCEPTION_PROLOG_ISERIES_1
ALT_FTR_SECTION_END_IFCLR(CPU_FTR_SLB)
b data_access_common
.do_stab_bolted_iSeries:
std r11,PACA_EXSLB+EX_R11(r13)
std r12,PACA_EXSLB+EX_R12(r13)
mfspr r10,SPRN_SPRG_SCRATCH0
std r10,PACA_EXSLB+EX_R13(r13)
EXCEPTION_PROLOG_ISERIES_1
b .do_stab_bolted
.globl data_access_slb_iSeries
data_access_slb_iSeries:
mtspr SPRN_SPRG_SCRATCH0,r13 /* save r13 */
mfspr r13,SPRN_SPRG_PACA /* get paca address into r13 */
std r3,PACA_EXSLB+EX_R3(r13)
mfspr r3,SPRN_DAR
std r9,PACA_EXSLB+EX_R9(r13)
mfcr r9
#ifdef __DISABLED__
cmpdi r3,0
bge slb_miss_user_iseries
#endif
std r10,PACA_EXSLB+EX_R10(r13)
std r11,PACA_EXSLB+EX_R11(r13)
std r12,PACA_EXSLB+EX_R12(r13)
mfspr r10,SPRN_SPRG_SCRATCH0
std r10,PACA_EXSLB+EX_R13(r13)
ld r12,PACALPPACAPTR(r13)
ld r12,LPPACASRR1(r12)
b .slb_miss_realmode
STD_EXCEPTION_ISERIES(instruction_access, PACA_EXGEN)
.globl instruction_access_slb_iSeries
instruction_access_slb_iSeries:
mtspr SPRN_SPRG_SCRATCH0,r13 /* save r13 */
mfspr r13,SPRN_SPRG_PACA /* get paca address into r13 */
std r3,PACA_EXSLB+EX_R3(r13)
ld r3,PACALPPACAPTR(r13)
ld r3,LPPACASRR0(r3) /* get SRR0 value */
std r9,PACA_EXSLB+EX_R9(r13)
mfcr r9
#ifdef __DISABLED__
cmpdi r3,0
bge slb_miss_user_iseries
#endif
std r10,PACA_EXSLB+EX_R10(r13)
std r11,PACA_EXSLB+EX_R11(r13)
std r12,PACA_EXSLB+EX_R12(r13)
mfspr r10,SPRN_SPRG_SCRATCH0
std r10,PACA_EXSLB+EX_R13(r13)
ld r12,PACALPPACAPTR(r13)
ld r12,LPPACASRR1(r12)
b .slb_miss_realmode
#ifdef __DISABLED__
slb_miss_user_iseries:
std r10,PACA_EXGEN+EX_R10(r13)
std r11,PACA_EXGEN+EX_R11(r13)
std r12,PACA_EXGEN+EX_R12(r13)
mfspr r10,SPRG_SCRATCH0
ld r11,PACA_EXSLB+EX_R9(r13)
ld r12,PACA_EXSLB+EX_R3(r13)
std r10,PACA_EXGEN+EX_R13(r13)
std r11,PACA_EXGEN+EX_R9(r13)
std r12,PACA_EXGEN+EX_R3(r13)
EXCEPTION_PROLOG_ISERIES_1
b slb_miss_user_common
#endif
MASKABLE_EXCEPTION_ISERIES(hardware_interrupt)
STD_EXCEPTION_ISERIES(alignment, PACA_EXGEN)
STD_EXCEPTION_ISERIES(program_check, PACA_EXGEN)
STD_EXCEPTION_ISERIES(fp_unavailable, PACA_EXGEN)
MASKABLE_EXCEPTION_ISERIES(decrementer)
STD_EXCEPTION_ISERIES(trap_0a, PACA_EXGEN)
STD_EXCEPTION_ISERIES(trap_0b, PACA_EXGEN)
.globl system_call_iSeries
system_call_iSeries:
mr r9,r13
mfspr r13,SPRN_SPRG_PACA
EXCEPTION_PROLOG_ISERIES_1
b system_call_common
STD_EXCEPTION_ISERIES(single_step, PACA_EXGEN)
STD_EXCEPTION_ISERIES(trap_0e, PACA_EXGEN)
STD_EXCEPTION_ISERIES(performance_monitor, PACA_EXGEN)
decrementer_iSeries_masked:
/* We may not have a valid TOC pointer in here. */
li r11,1
ld r12,PACALPPACAPTR(r13)
stb r11,LPPACADECRINT(r12)
LOAD_REG_IMMEDIATE(r12, tb_ticks_per_jiffy)
lwz r12,0(r12)
mtspr SPRN_DEC,r12
/* fall through */
hardware_interrupt_iSeries_masked:
mtcrf 0x80,r9 /* Restore regs */
ld r12,PACALPPACAPTR(r13)
ld r11,LPPACASRR0(r12)
ld r12,LPPACASRR1(r12)
mtspr SPRN_SRR0,r11
mtspr SPRN_SRR1,r12
ld r9,PACA_EXGEN+EX_R9(r13)
ld r10,PACA_EXGEN+EX_R10(r13)
ld r11,PACA_EXGEN+EX_R11(r13)
ld r12,PACA_EXGEN+EX_R12(r13)
ld r13,PACA_EXGEN+EX_R13(r13)
rfid
b . /* prevent speculative execution */
_INIT_STATIC(__start_initialization_iSeries)
/* Clear out the BSS */
LOAD_REG_ADDR(r11,__bss_stop)
LOAD_REG_ADDR(r8,__bss_start)
sub r11,r11,r8 /* bss size */
addi r11,r11,7 /* round up to an even double word */
rldicl. r11,r11,61,3 /* shift right by 3 */
beq 4f
addi r8,r8,-8
li r0,0
mtctr r11 /* zero this many doublewords */
3: stdu r0,8(r8)
bdnz 3b
4:
LOAD_REG_ADDR(r1,init_thread_union)
addi r1,r1,THREAD_SIZE
li r0,0
stdu r0,-STACK_FRAME_OVERHEAD(r1)
bl .iSeries_early_setup
bl .early_setup
/* relocation is on at this point */
b .start_here_common
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