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linux/arch/powerpc/kernel/head_64.S
Benjamin Herrenschmidt ab7f961a58 powerpc/powernv: Fix OPAL debug entry 
OPAL provides the firmware base/entry in registers at boot time
for debugging purposes. We had a bug in the code trying to stash
these into the appropriate kernel globals (a line of code was
probably dropped by accident back when this was merged)

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-11-15 13:00:14 +11:00

791 lines
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/*
* 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 entry point for the 64-bit kernel along
* with some early initialization code common to all 64-bit powerpc
* variants.
*
* 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/threads.h>
#include <asm/reg.h>
#include <asm/page.h>
#include <asm/mmu.h>
#include <asm/ppc_asm.h>
#include <asm/asm-offsets.h>
#include <asm/bug.h>
#include <asm/cputable.h>
#include <asm/setup.h>
#include <asm/hvcall.h>
#include <asm/thread_info.h>
#include <asm/firmware.h>
#include <asm/page_64.h>
#include <asm/irqflags.h>
#include <asm/kvm_book3s_asm.h>
#include <asm/ptrace.h>
#include <asm/hw_irq.h>
/* The physical memory is laid out such that the secondary processor
* spin code sits at 0x0000...0x00ff. On server, the vectors follow
* using the layout described in exceptions-64s.S
*/
/*
* Entering into this code we make the following assumptions:
*
* For pSeries or server processors:
* 1. The MMU is off & open firmware is running in real mode.
* 2. The kernel is entered at __start
* -or- For OPAL entry:
* 1. The MMU is off, processor in HV mode, primary CPU enters at 0
* with device-tree in gpr3. We also get OPAL base in r8 and
* entry in r9 for debugging purposes
* 2. Secondary processors enter at 0x60 with PIR in gpr3
*
* For Book3E processors:
* 1. The MMU is on running in AS0 in a state defined in ePAPR
* 2. The kernel is entered at __start
*/
.text
.globl _stext
_stext:
_GLOBAL(__start)
/* NOP this out unconditionally */
BEGIN_FTR_SECTION
b .__start_initialization_multiplatform
END_FTR_SECTION(0, 1)
/* Catch branch to 0 in real mode */
trap
/* Secondary processors spin on this value until it becomes nonzero.
* When it does it contains the real address of the descriptor
* of the function that the cpu should jump to to continue
* initialization.
*/
.globl __secondary_hold_spinloop
__secondary_hold_spinloop:
.llong 0x0
/* Secondary processors write this value with their cpu # */
/* after they enter the spin loop immediately below. */
.globl __secondary_hold_acknowledge
__secondary_hold_acknowledge:
.llong 0x0
#ifdef CONFIG_RELOCATABLE
/* This flag is set to 1 by a loader if the kernel should run
* at the loaded address instead of the linked address. This
* is used by kexec-tools to keep the the kdump kernel in the
* crash_kernel region. The loader is responsible for
* observing the alignment requirement.
*/
/* Do not move this variable as kexec-tools knows about it. */
. = 0x5c
.globl __run_at_load
__run_at_load:
.long 0x72756e30 /* "run0" -- relocate to 0 by default */
#endif
. = 0x60
/*
* The following code is used to hold secondary processors
* in a spin loop after they have entered the kernel, but
* before the bulk of the kernel has been relocated. This code
* is relocated to physical address 0x60 before prom_init is run.
* All of it must fit below the first exception vector at 0x100.
* Use .globl here not _GLOBAL because we want __secondary_hold
* to be the actual text address, not a descriptor.
*/
.globl __secondary_hold
__secondary_hold:
#ifndef CONFIG_PPC_BOOK3E
mfmsr r24
ori r24,r24,MSR_RI
mtmsrd r24 /* RI on */
#endif
/* Grab our physical cpu number */
mr r24,r3
/* Tell the master cpu we're here */
/* Relocation is off & we are located at an address less */
/* than 0x100, so only need to grab low order offset. */
std r24,__secondary_hold_acknowledge-_stext(0)
sync
/* All secondary cpus wait here until told to start. */
100: ld r4,__secondary_hold_spinloop-_stext(0)
cmpdi 0,r4,0
beq 100b
#if defined(CONFIG_SMP) || defined(CONFIG_KEXEC)
ld r4,0(r4) /* deref function descriptor */
mtctr r4
mr r3,r24
li r4,0
/* Make sure that patched code is visible */
isync
bctr
#else
BUG_OPCODE
#endif
/* This value is used to mark exception frames on the stack. */
.section ".toc","aw"
exception_marker:
.tc ID_72656773_68657265[TC],0x7265677368657265
.text
/*
* On server, we include the exception vectors code here as it
* relies on absolute addressing which is only possible within
* this compilation unit
*/
#ifdef CONFIG_PPC_BOOK3S
#include "exceptions-64s.S"
#endif
_GLOBAL(generic_secondary_thread_init)
mr r24,r3
/* turn on 64-bit mode */
bl .enable_64b_mode
/* get a valid TOC pointer, wherever we're mapped at */
bl .relative_toc
#ifdef CONFIG_PPC_BOOK3E
/* Book3E initialization */
mr r3,r24
bl .book3e_secondary_thread_init
#endif
b generic_secondary_common_init
/*
* On pSeries and most other platforms, secondary processors spin
* in the following code.
* At entry, r3 = this processor's number (physical cpu id)
*
* On Book3E, r4 = 1 to indicate that the initial TLB entry for
* this core already exists (setup via some other mechanism such
* as SCOM before entry).
*/
_GLOBAL(generic_secondary_smp_init)
mr r24,r3
mr r25,r4
/* turn on 64-bit mode */
bl .enable_64b_mode
/* get a valid TOC pointer, wherever we're mapped at */
bl .relative_toc
#ifdef CONFIG_PPC_BOOK3E
/* Book3E initialization */
mr r3,r24
mr r4,r25
bl .book3e_secondary_core_init
#endif
generic_secondary_common_init:
/* Set up a paca value for this processor. Since we have the
* physical cpu id in r24, we need to search the pacas to find
* which logical id maps to our physical one.
*/
LOAD_REG_ADDR(r13, paca) /* Load paca pointer */
ld r13,0(r13) /* Get base vaddr of paca array */
#ifndef CONFIG_SMP
addi r13,r13,PACA_SIZE /* know r13 if used accidentally */
b .kexec_wait /* wait for next kernel if !SMP */
#else
LOAD_REG_ADDR(r7, nr_cpu_ids) /* Load nr_cpu_ids address */
lwz r7,0(r7) /* also the max paca allocated */
li r5,0 /* logical cpu id */
1: lhz r6,PACAHWCPUID(r13) /* Load HW procid from paca */
cmpw r6,r24 /* Compare to our id */
beq 2f
addi r13,r13,PACA_SIZE /* Loop to next PACA on miss */
addi r5,r5,1
cmpw r5,r7 /* Check if more pacas exist */
blt 1b
mr r3,r24 /* not found, copy phys to r3 */
b .kexec_wait /* next kernel might do better */
2: SET_PACA(r13)
#ifdef CONFIG_PPC_BOOK3E
addi r12,r13,PACA_EXTLB /* and TLB exc frame in another */
mtspr SPRN_SPRG_TLB_EXFRAME,r12
#endif
/* From now on, r24 is expected to be logical cpuid */
mr r24,r5
/* See if we need to call a cpu state restore handler */
LOAD_REG_ADDR(r23, cur_cpu_spec)
ld r23,0(r23)
ld r23,CPU_SPEC_RESTORE(r23)
cmpdi 0,r23,0
beq 3f
ld r23,0(r23)
mtctr r23
bctrl
3: LOAD_REG_ADDR(r3, spinning_secondaries) /* Decrement spinning_secondaries */
lwarx r4,0,r3
subi r4,r4,1
stwcx. r4,0,r3
bne 3b
isync
4: HMT_LOW
lbz r23,PACAPROCSTART(r13) /* Test if this processor should */
/* start. */
cmpwi 0,r23,0
beq 4b /* Loop until told to go */
sync /* order paca.run and cur_cpu_spec */
isync /* In case code patching happened */
/* Create a temp kernel stack for use before relocation is on. */
ld r1,PACAEMERGSP(r13)
subi r1,r1,STACK_FRAME_OVERHEAD
b __secondary_start
#endif /* SMP */
/*
* Turn the MMU off.
* Assumes we're mapped EA == RA if the MMU is on.
*/
#ifdef CONFIG_PPC_BOOK3S
_STATIC(__mmu_off)
mfmsr r3
andi. r0,r3,MSR_IR|MSR_DR
beqlr
mflr r4
andc r3,r3,r0
mtspr SPRN_SRR0,r4
mtspr SPRN_SRR1,r3
sync
rfid
b . /* prevent speculative execution */
#endif
/*
* Here is our main kernel entry point. We support currently 2 kind of entries
* depending on the value of r5.
*
* r5 != NULL -> OF entry, we go to prom_init, "legacy" parameter content
* in r3...r7
*
* r5 == NULL -> kexec style entry. r3 is a physical pointer to the
* DT block, r4 is a physical pointer to the kernel itself
*
*/
_GLOBAL(__start_initialization_multiplatform)
/* Make sure we are running in 64 bits mode */
bl .enable_64b_mode
/* Get TOC pointer (current runtime address) */
bl .relative_toc
/* find out where we are now */
bcl 20,31,$+4
0: mflr r26 /* r26 = runtime addr here */
addis r26,r26,(_stext - 0b)@ha
addi r26,r26,(_stext - 0b)@l /* current runtime base addr */
/*
* Are we booted from a PROM Of-type client-interface ?
*/
cmpldi cr0,r5,0
beq 1f
b .__boot_from_prom /* yes -> prom */
1:
/* Save parameters */
mr r31,r3
mr r30,r4
#ifdef CONFIG_PPC_EARLY_DEBUG_OPAL
/* Save OPAL entry */
mr r28,r8
mr r29,r9
#endif
#ifdef CONFIG_PPC_BOOK3E
bl .start_initialization_book3e
b .__after_prom_start
#else
/* Setup some critical 970 SPRs before switching MMU off */
mfspr r0,SPRN_PVR
srwi r0,r0,16
cmpwi r0,0x39 /* 970 */
beq 1f
cmpwi r0,0x3c /* 970FX */
beq 1f
cmpwi r0,0x44 /* 970MP */
beq 1f
cmpwi r0,0x45 /* 970GX */
bne 2f
1: bl .__cpu_preinit_ppc970
2:
/* Switch off MMU if not already off */
bl .__mmu_off
b .__after_prom_start
#endif /* CONFIG_PPC_BOOK3E */
_INIT_STATIC(__boot_from_prom)
#ifdef CONFIG_PPC_OF_BOOT_TRAMPOLINE
/* Save parameters */
mr r31,r3
mr r30,r4
mr r29,r5
mr r28,r6
mr r27,r7
/*
* Align the stack to 16-byte boundary
* Depending on the size and layout of the ELF sections in the initial
* boot binary, the stack pointer may be unaligned on PowerMac
*/
rldicr r1,r1,0,59
#ifdef CONFIG_RELOCATABLE
/* Relocate code for where we are now */
mr r3,r26
bl .relocate
#endif
/* Restore parameters */
mr r3,r31
mr r4,r30
mr r5,r29
mr r6,r28
mr r7,r27
/* Do all of the interaction with OF client interface */
mr r8,r26
bl .prom_init
#endif /* #CONFIG_PPC_OF_BOOT_TRAMPOLINE */
/* We never return. We also hit that trap if trying to boot
* from OF while CONFIG_PPC_OF_BOOT_TRAMPOLINE isn't selected */
trap
_STATIC(__after_prom_start)
#ifdef CONFIG_RELOCATABLE
/* process relocations for the final address of the kernel */
lis r25,PAGE_OFFSET@highest /* compute virtual base of kernel */
sldi r25,r25,32
lwz r7,__run_at_load-_stext(r26)
cmplwi cr0,r7,1 /* flagged to stay where we are ? */
bne 1f
add r25,r25,r26
1: mr r3,r25
bl .relocate
#endif
/*
* We need to run with _stext at physical address PHYSICAL_START.
* This will leave some code in the first 256B of
* real memory, which are reserved for software use.
*
* Note: This process overwrites the OF exception vectors.
*/
li r3,0 /* target addr */
#ifdef CONFIG_PPC_BOOK3E
tovirt(r3,r3) /* on booke, we already run at PAGE_OFFSET */
#endif
mr. r4,r26 /* In some cases the loader may */
beq 9f /* have already put us at zero */
li r6,0x100 /* Start offset, the first 0x100 */
/* bytes were copied earlier. */
#ifdef CONFIG_PPC_BOOK3E
tovirt(r6,r6) /* on booke, we already run at PAGE_OFFSET */
#endif
#ifdef CONFIG_CRASH_DUMP
/*
* Check if the kernel has to be running as relocatable kernel based on the
* variable __run_at_load, if it is set the kernel is treated as relocatable
* kernel, otherwise it will be moved to PHYSICAL_START
*/
lwz r7,__run_at_load-_stext(r26)
cmplwi cr0,r7,1
bne 3f
li r5,__end_interrupts - _stext /* just copy interrupts */
b 5f
3:
#endif
lis r5,(copy_to_here - _stext)@ha
addi r5,r5,(copy_to_here - _stext)@l /* # bytes of memory to copy */
bl .copy_and_flush /* copy the first n bytes */
/* this includes the code being */
/* executed here. */
addis r8,r3,(4f - _stext)@ha /* Jump to the copy of this code */
addi r8,r8,(4f - _stext)@l /* that we just made */
mtctr r8
bctr
p_end: .llong _end - _stext
4: /* Now copy the rest of the kernel up to _end */
addis r5,r26,(p_end - _stext)@ha
ld r5,(p_end - _stext)@l(r5) /* get _end */
5: bl .copy_and_flush /* copy the rest */
9: b .start_here_multiplatform
/*
* Copy routine used to copy the kernel to start at physical address 0
* and flush and invalidate the caches as needed.
* r3 = dest addr, r4 = source addr, r5 = copy limit, r6 = start offset
* on exit, r3, r4, r5 are unchanged, r6 is updated to be >= r5.
*
* Note: this routine *only* clobbers r0, r6 and lr
*/
_GLOBAL(copy_and_flush)
addi r5,r5,-8
addi r6,r6,-8
4: li r0,8 /* Use the smallest common */
/* denominator cache line */
/* size. This results in */
/* extra cache line flushes */
/* but operation is correct. */
/* Can't get cache line size */
/* from NACA as it is being */
/* moved too. */
mtctr r0 /* put # words/line in ctr */
3: addi r6,r6,8 /* copy a cache line */
ldx r0,r6,r4
stdx r0,r6,r3
bdnz 3b
dcbst r6,r3 /* write it to memory */
sync
icbi r6,r3 /* flush the icache line */
cmpld 0,r6,r5
blt 4b
sync
addi r5,r5,8
addi r6,r6,8
blr
.align 8
copy_to_here:
#ifdef CONFIG_SMP
#ifdef CONFIG_PPC_PMAC
/*
* On PowerMac, secondary processors starts from the reset vector, which
* is temporarily turned into a call to one of the functions below.
*/
.section ".text";
.align 2 ;
.globl __secondary_start_pmac_0
__secondary_start_pmac_0:
/* NB the entries for cpus 0, 1, 2 must each occupy 8 bytes. */
li r24,0
b 1f
li r24,1
b 1f
li r24,2
b 1f
li r24,3
1:
_GLOBAL(pmac_secondary_start)
/* turn on 64-bit mode */
bl .enable_64b_mode
li r0,0
mfspr r3,SPRN_HID4
rldimi r3,r0,40,23 /* clear bit 23 (rm_ci) */
sync
mtspr SPRN_HID4,r3
isync
sync
slbia
/* get TOC pointer (real address) */
bl .relative_toc
/* Copy some CPU settings from CPU 0 */
bl .__restore_cpu_ppc970
/* pSeries do that early though I don't think we really need it */
mfmsr r3
ori r3,r3,MSR_RI
mtmsrd r3 /* RI on */
/* Set up a paca value for this processor. */
LOAD_REG_ADDR(r4,paca) /* Load paca pointer */
ld r4,0(r4) /* Get base vaddr of paca array */
mulli r13,r24,PACA_SIZE /* Calculate vaddr of right paca */
add r13,r13,r4 /* for this processor. */
SET_PACA(r13) /* Save vaddr of paca in an SPRG*/
/* Mark interrupts soft and hard disabled (they might be enabled
* in the PACA when doing hotplug)
*/
li r0,0
stb r0,PACASOFTIRQEN(r13)
li r0,PACA_IRQ_HARD_DIS
stb r0,PACAIRQHAPPENED(r13)
/* Create a temp kernel stack for use before relocation is on. */
ld r1,PACAEMERGSP(r13)
subi r1,r1,STACK_FRAME_OVERHEAD
b __secondary_start
#endif /* CONFIG_PPC_PMAC */
/*
* This function is called after the master CPU has released the
* secondary processors. The execution environment is relocation off.
* The paca for this processor has the following fields initialized at
* this point:
* 1. Processor number
* 2. Segment table pointer (virtual address)
* On entry the following are set:
* r1 = stack pointer (real addr of temp stack)
* r24 = cpu# (in Linux terms)
* r13 = paca virtual address
* SPRG_PACA = paca virtual address
*/
.section ".text";
.align 2 ;
.globl __secondary_start
__secondary_start:
/* Set thread priority to MEDIUM */
HMT_MEDIUM
/* Initialize the kernel stack */
LOAD_REG_ADDR(r3, current_set)
sldi r28,r24,3 /* get current_set[cpu#] */
ldx r14,r3,r28
addi r14,r14,THREAD_SIZE-STACK_FRAME_OVERHEAD
std r14,PACAKSAVE(r13)
/* Do early setup for that CPU (stab, slb, hash table pointer) */
bl .early_setup_secondary
/*
* setup the new stack pointer, but *don't* use this until
* translation is on.
*/
mr r1, r14
/* Clear backchain so we get nice backtraces */
li r7,0
mtlr r7
/* Mark interrupts soft and hard disabled (they might be enabled
* in the PACA when doing hotplug)
*/
stb r7,PACASOFTIRQEN(r13)
li r0,PACA_IRQ_HARD_DIS
stb r0,PACAIRQHAPPENED(r13)
/* enable MMU and jump to start_secondary */
LOAD_REG_ADDR(r3, .start_secondary_prolog)
LOAD_REG_IMMEDIATE(r4, MSR_KERNEL)
mtspr SPRN_SRR0,r3
mtspr SPRN_SRR1,r4
RFI
b . /* prevent speculative execution */
/*
* Running with relocation on at this point. All we want to do is
* zero the stack back-chain pointer and get the TOC virtual address
* before going into C code.
*/
_GLOBAL(start_secondary_prolog)
ld r2,PACATOC(r13)
li r3,0
std r3,0(r1) /* Zero the stack frame pointer */
bl .start_secondary
b .
/*
* Reset stack pointer and call start_secondary
* to continue with online operation when woken up
* from cede in cpu offline.
*/
_GLOBAL(start_secondary_resume)
ld r1,PACAKSAVE(r13) /* Reload kernel stack pointer */
li r3,0
std r3,0(r1) /* Zero the stack frame pointer */
bl .start_secondary
b .
#endif
/*
* This subroutine clobbers r11 and r12
*/
_GLOBAL(enable_64b_mode)
mfmsr r11 /* grab the current MSR */
#ifdef CONFIG_PPC_BOOK3E
oris r11,r11,0x8000 /* CM bit set, we'll set ICM later */
mtmsr r11
#else /* CONFIG_PPC_BOOK3E */
li r12,(MSR_64BIT | MSR_ISF)@highest
sldi r12,r12,48
or r11,r11,r12
mtmsrd r11
isync
#endif
blr
/*
* This puts the TOC pointer into r2, offset by 0x8000 (as expected
* by the toolchain). It computes the correct value for wherever we
* are running at the moment, using position-independent code.
*/
_GLOBAL(relative_toc)
mflr r0
bcl 20,31,$+4
0: mflr r11
ld r2,(p_toc - 0b)(r11)
add r2,r2,r11
mtlr r0
blr
p_toc: .llong __toc_start + 0x8000 - 0b
/*
* This is where the main kernel code starts.
*/
_INIT_STATIC(start_here_multiplatform)
/* set up the TOC (real address) */
bl .relative_toc
/* Clear out the BSS. It may have been done in prom_init,
* already but that's irrelevant since prom_init will soon
* be detached from the kernel completely. Besides, we need
* to clear it now for kexec-style entry.
*/
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 */
srdi. r11,r11,3 /* 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:
#ifdef CONFIG_PPC_EARLY_DEBUG_OPAL
/* Setup OPAL entry */
LOAD_REG_ADDR(r11, opal)
std r28,0(r11);
std r29,8(r11);
#endif
#ifndef CONFIG_PPC_BOOK3E
mfmsr r6
ori r6,r6,MSR_RI
mtmsrd r6 /* RI on */
#endif
#ifdef CONFIG_RELOCATABLE
/* Save the physical address we're running at in kernstart_addr */
LOAD_REG_ADDR(r4, kernstart_addr)
clrldi r0,r25,2
std r0,0(r4)
#endif
/* The following gets the stack set up with the regs */
/* pointing to the real addr of the kernel stack. This is */
/* all done to support the C function call below which sets */
/* up the htab. This is done because we have relocated the */
/* kernel but are still running in real mode. */
LOAD_REG_ADDR(r3,init_thread_union)
/* set up a stack pointer */
addi r1,r3,THREAD_SIZE
li r0,0
stdu r0,-STACK_FRAME_OVERHEAD(r1)
/* Do very early kernel initializations, including initial hash table,
* stab and slb setup before we turn on relocation. */
/* Restore parameters passed from prom_init/kexec */
mr r3,r31
bl .early_setup /* also sets r13 and SPRG_PACA */
LOAD_REG_ADDR(r3, .start_here_common)
ld r4,PACAKMSR(r13)
mtspr SPRN_SRR0,r3
mtspr SPRN_SRR1,r4
RFI
b . /* prevent speculative execution */
/* This is where all platforms converge execution */
_INIT_GLOBAL(start_here_common)
/* relocation is on at this point */
std r1,PACAKSAVE(r13)
/* Load the TOC (virtual address) */
ld r2,PACATOC(r13)
/* Do more system initializations in virtual mode */
bl .setup_system
/* Mark interrupts soft and hard disabled (they might be enabled
* in the PACA when doing hotplug)
*/
li r0,0
stb r0,PACASOFTIRQEN(r13)
li r0,PACA_IRQ_HARD_DIS
stb r0,PACAIRQHAPPENED(r13)
/* Generic kernel entry */
bl .start_kernel
/* Not reached */
BUG_OPCODE
/*
* We put a few things here that have to be page-aligned.
* This stuff goes at the beginning of the bss, which is page-aligned.
*/
.section ".bss"
.align PAGE_SHIFT
.globl empty_zero_page
empty_zero_page:
.space PAGE_SIZE
.globl swapper_pg_dir
swapper_pg_dir:
.space PGD_TABLE_SIZE
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