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linux/arch/powerpc/platforms/iseries/exception.S
Paul Mackerras e62cee42e6 powerpc: Avoid bad relocations in iSeries code 
Subrata Modak reported that building a CONFIG_RELOCATABLE kernel with
CONFIG_ISERIES enabled gives the following warnings:

WARNING: 4 bad relocations
c00000000007216e R_PPC64_ADDR16_HIGHEST  __ksymtab+0x00000000009dcec8
c000000000072172 R_PPC64_ADDR16_HIGHER  __ksymtab+0x00000000009dcec8
c00000000007217a R_PPC64_ADDR16_HI  __ksymtab+0x00000000009dcec8
c00000000007217e R_PPC64_ADDR16_LO  __ksymtab+0x00000000009dcec8

The reason is that decrementer_iSeries_masked is using
LOAD_REG_IMMEDIATE to get the address of a kernel symbol, which
creates relocations that aren't handled by the kernel relocator code.

Instead of reading the tb_ticks_per_jiffy variable, we can just set
the decrementer to its maximum value (0x7fffffff) and that will work
just as well.  In fact timer_interrupt sets the decrementer to that
value initially anyway, and we are sure to get into timer_interrupt
once interrupts are reenabled because we store 1 to the decrementer
interrupt flag in the lppaca (LPPACADECRINT(r12) here).

Reported-by: Subrata Modak <subrata@linux.vnet.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2010-05-21 17:31:08 +10:00

299 lines
8.3 KiB
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Raw Blame History

/*
* 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)
li r12,-1
clrldi r12,r12,33 /* set DEC to 0x7fffffff */
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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