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linux/arch/powerpc/kernel/head_32.S
Benjamin Herrenschmidt 4a5cbf17c4 powerpc: Map more memory early on 601 processors 
The 32-bit kernel relies on some memory being mapped covering
the kernel text,data and bss at least, early during boot before
the full MMU setup is done. On 32-bit "classic" processors, this
is done using BAT registers.

On 601, the size of BATs is limited to 8M and we use 2 of them
for that initial mapping. This can become quite tight when enabling
features like lockdep, so let's use a 3rd one to bump that mapping
from 16M to 24M. We keep the 4th BAT free as it can be useful for
debugging early boot code to map things like serial ports.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-06-26 14:37:25 +10:00

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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.
* MPC8xx modifications Copyright (C) 1997 Dan Malek (dmalek@jlc.net).
*
* This file contains the low-level support and setup for the
* PowerPC platform, including trap and interrupt dispatch.
* (The PPC 8xx embedded CPUs use head_8xx.S instead.)
*
* 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/init.h>
#include <asm/reg.h>
#include <asm/page.h>
#include <asm/mmu.h>
#include <asm/pgtable.h>
#include <asm/cputable.h>
#include <asm/cache.h>
#include <asm/thread_info.h>
#include <asm/ppc_asm.h>
#include <asm/asm-offsets.h>
#include <asm/ptrace.h>
#include <asm/bug.h>
/* 601 only have IBAT; cr0.eq is set on 601 when using this macro */
#define LOAD_BAT(n, reg, RA, RB) \
/* see the comment for clear_bats() -- Cort */ \
li RA,0; \
mtspr SPRN_IBAT##n##U,RA; \
mtspr SPRN_DBAT##n##U,RA; \
lwz RA,(n*16)+0(reg); \
lwz RB,(n*16)+4(reg); \
mtspr SPRN_IBAT##n##U,RA; \
mtspr SPRN_IBAT##n##L,RB; \
beq 1f; \
lwz RA,(n*16)+8(reg); \
lwz RB,(n*16)+12(reg); \
mtspr SPRN_DBAT##n##U,RA; \
mtspr SPRN_DBAT##n##L,RB; \
1:
__HEAD
.stabs "arch/powerpc/kernel/",N_SO,0,0,0f
.stabs "head_32.S",N_SO,0,0,0f
0:
_ENTRY(_stext);
/*
* _start is defined this way because the XCOFF loader in the OpenFirmware
* on the powermac expects the entry point to be a procedure descriptor.
*/
_ENTRY(_start);
/*
* These are here for legacy reasons, the kernel used to
* need to look like a coff function entry for the pmac
* but we're always started by some kind of bootloader now.
* -- Cort
*/
nop /* used by __secondary_hold on prep (mtx) and chrp smp */
nop /* used by __secondary_hold on prep (mtx) and chrp smp */
nop
/* PMAC
* Enter here with the kernel text, data and bss loaded starting at
* 0, running with virtual == physical mapping.
* r5 points to the prom entry point (the client interface handler
* address). Address translation is turned on, with the prom
* managing the hash table. Interrupts are disabled. The stack
* pointer (r1) points to just below the end of the half-meg region
* from 0x380000 - 0x400000, which is mapped in already.
*
* If we are booted from MacOS via BootX, we enter with the kernel
* image loaded somewhere, and the following values in registers:
* r3: 'BooX' (0x426f6f58)
* r4: virtual address of boot_infos_t
* r5: 0
*
* PREP
* This is jumped to on prep systems right after the kernel is relocated
* to its proper place in memory by the boot loader. The expected layout
* of the regs is:
* r3: ptr to residual data
* r4: initrd_start or if no initrd then 0
* r5: initrd_end - unused if r4 is 0
* r6: Start of command line string
* r7: End of command line string
*
* This just gets a minimal mmu environment setup so we can call
* start_here() to do the real work.
* -- Cort
*/
.globl __start
__start:
/*
* We have to do any OF calls before we map ourselves to KERNELBASE,
* because OF may have I/O devices mapped into that area
* (particularly on CHRP).
*/
cmpwi 0,r5,0
beq 1f
#ifdef CONFIG_PPC_OF_BOOT_TRAMPOLINE
/* find out where we are now */
bcl 20,31,$+4
0: mflr r8 /* r8 = runtime addr here */
addis r8,r8,(_stext - 0b)@ha
addi r8,r8,(_stext - 0b)@l /* current runtime base addr */
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
/*
* Check for BootX signature when supporting PowerMac and branch to
* appropriate trampoline if it's present
*/
#ifdef CONFIG_PPC_PMAC
1: lis r31,0x426f
ori r31,r31,0x6f58
cmpw 0,r3,r31
bne 1f
bl bootx_init
trap
#endif /* CONFIG_PPC_PMAC */
1: mr r31,r3 /* save parameters */
mr r30,r4
li r24,0 /* cpu # */
/*
* early_init() does the early machine identification and does
* the necessary low-level setup and clears the BSS
* -- Cort <cort@fsmlabs.com>
*/
bl early_init
/* Switch MMU off, clear BATs and flush TLB. At this point, r3 contains
* the physical address we are running at, returned by early_init()
*/
bl mmu_off
__after_mmu_off:
bl clear_bats
bl flush_tlbs
bl initial_bats
#if defined(CONFIG_BOOTX_TEXT)
bl setup_disp_bat
#endif
#ifdef CONFIG_PPC_EARLY_DEBUG_CPM
bl setup_cpm_bat
#endif
/*
* Call setup_cpu for CPU 0 and initialize 6xx Idle
*/
bl reloc_offset
li r24,0 /* cpu# */
bl call_setup_cpu /* Call setup_cpu for this CPU */
#ifdef CONFIG_6xx
bl reloc_offset
bl init_idle_6xx
#endif /* CONFIG_6xx */
/*
* We need to run with _start at physical address 0.
* On CHRP, we are loaded at 0x10000 since OF on CHRP uses
* the exception vectors at 0 (and therefore this copy
* overwrites OF's exception vectors with our own).
* The MMU is off at this point.
*/
bl reloc_offset
mr r26,r3
addis r4,r3,KERNELBASE@h /* current address of _start */
lis r5,PHYSICAL_START@h
cmplw 0,r4,r5 /* already running at PHYSICAL_START? */
bne relocate_kernel
/*
* we now have the 1st 16M of ram mapped with the bats.
* prep needs the mmu to be turned on here, but pmac already has it on.
* this shouldn't bother the pmac since it just gets turned on again
* as we jump to our code at KERNELBASE. -- Cort
* Actually no, pmac doesn't have it on any more. BootX enters with MMU
* off, and in other cases, we now turn it off before changing BATs above.
*/
turn_on_mmu:
mfmsr r0
ori r0,r0,MSR_DR|MSR_IR
mtspr SPRN_SRR1,r0
lis r0,start_here@h
ori r0,r0,start_here@l
mtspr SPRN_SRR0,r0
SYNC
RFI /* enables MMU */
/*
* We need __secondary_hold as a place to hold the other cpus on
* an SMP machine, even when we are running a UP kernel.
*/
. = 0xc0 /* for prep bootloader */
li r3,1 /* MTX only has 1 cpu */
.globl __secondary_hold
__secondary_hold:
/* tell the master we're here */
stw r3,__secondary_hold_acknowledge@l(0)
#ifdef CONFIG_SMP
100: lwz r4,0(0)
/* wait until we're told to start */
cmpw 0,r4,r3
bne 100b
/* our cpu # was at addr 0 - go */
mr r24,r3 /* cpu # */
b __secondary_start
#else
b .
#endif /* CONFIG_SMP */
.globl __secondary_hold_spinloop
__secondary_hold_spinloop:
.long 0
.globl __secondary_hold_acknowledge
__secondary_hold_acknowledge:
.long -1
/*
* Exception entry code. This code runs with address translation
* turned off, i.e. using physical addresses.
* We assume sprg3 has the physical address of the current
* task's thread_struct.
*/
#define EXCEPTION_PROLOG \
mtspr SPRN_SPRG0,r10; \
mtspr SPRN_SPRG1,r11; \
mfcr r10; \
EXCEPTION_PROLOG_1; \
EXCEPTION_PROLOG_2
#define EXCEPTION_PROLOG_1 \
mfspr r11,SPRN_SRR1; /* check whether user or kernel */ \
andi. r11,r11,MSR_PR; \
tophys(r11,r1); /* use tophys(r1) if kernel */ \
beq 1f; \
mfspr r11,SPRN_SPRG3; \
lwz r11,THREAD_INFO-THREAD(r11); \
addi r11,r11,THREAD_SIZE; \
tophys(r11,r11); \
1: subi r11,r11,INT_FRAME_SIZE /* alloc exc. frame */
#define EXCEPTION_PROLOG_2 \
CLR_TOP32(r11); \
stw r10,_CCR(r11); /* save registers */ \
stw r12,GPR12(r11); \
stw r9,GPR9(r11); \
mfspr r10,SPRN_SPRG0; \
stw r10,GPR10(r11); \
mfspr r12,SPRN_SPRG1; \
stw r12,GPR11(r11); \
mflr r10; \
stw r10,_LINK(r11); \
mfspr r12,SPRN_SRR0; \
mfspr r9,SPRN_SRR1; \
stw r1,GPR1(r11); \
stw r1,0(r11); \
tovirt(r1,r11); /* set new kernel sp */ \
li r10,MSR_KERNEL & ~(MSR_IR|MSR_DR); /* can take exceptions */ \
MTMSRD(r10); /* (except for mach check in rtas) */ \
stw r0,GPR0(r11); \
lis r10,STACK_FRAME_REGS_MARKER@ha; /* exception frame marker */ \
addi r10,r10,STACK_FRAME_REGS_MARKER@l; \
stw r10,8(r11); \
SAVE_4GPRS(3, r11); \
SAVE_2GPRS(7, r11)
/*
* Note: code which follows this uses cr0.eq (set if from kernel),
* r11, r12 (SRR0), and r9 (SRR1).
*
* Note2: once we have set r1 we are in a position to take exceptions
* again, and we could thus set MSR:RI at that point.
*/
/*
* Exception vectors.
*/
#define EXCEPTION(n, label, hdlr, xfer) \
. = n; \
label: \
EXCEPTION_PROLOG; \
addi r3,r1,STACK_FRAME_OVERHEAD; \
xfer(n, hdlr)
#define EXC_XFER_TEMPLATE(n, hdlr, trap, copyee, tfer, ret) \
li r10,trap; \
stw r10,_TRAP(r11); \
li r10,MSR_KERNEL; \
copyee(r10, r9); \
bl tfer; \
i##n: \
.long hdlr; \
.long ret
#define COPY_EE(d, s) rlwimi d,s,0,16,16
#define NOCOPY(d, s)
#define EXC_XFER_STD(n, hdlr) \
EXC_XFER_TEMPLATE(n, hdlr, n, NOCOPY, transfer_to_handler_full, \
ret_from_except_full)
#define EXC_XFER_LITE(n, hdlr) \
EXC_XFER_TEMPLATE(n, hdlr, n+1, NOCOPY, transfer_to_handler, \
ret_from_except)
#define EXC_XFER_EE(n, hdlr) \
EXC_XFER_TEMPLATE(n, hdlr, n, COPY_EE, transfer_to_handler_full, \
ret_from_except_full)
#define EXC_XFER_EE_LITE(n, hdlr) \
EXC_XFER_TEMPLATE(n, hdlr, n+1, COPY_EE, transfer_to_handler, \
ret_from_except)
/* System reset */
/* core99 pmac starts the seconary here by changing the vector, and
putting it back to what it was (unknown_exception) when done. */
EXCEPTION(0x100, Reset, unknown_exception, EXC_XFER_STD)
/* Machine check */
/*
* On CHRP, this is complicated by the fact that we could get a
* machine check inside RTAS, and we have no guarantee that certain
* critical registers will have the values we expect. The set of
* registers that might have bad values includes all the GPRs
* and all the BATs. We indicate that we are in RTAS by putting
* a non-zero value, the address of the exception frame to use,
* in SPRG2. The machine check handler checks SPRG2 and uses its
* value if it is non-zero. If we ever needed to free up SPRG2,
* we could use a field in the thread_info or thread_struct instead.
* (Other exception handlers assume that r1 is a valid kernel stack
* pointer when we take an exception from supervisor mode.)
* -- paulus.
*/
. = 0x200
mtspr SPRN_SPRG0,r10
mtspr SPRN_SPRG1,r11
mfcr r10
#ifdef CONFIG_PPC_CHRP
mfspr r11,SPRN_SPRG2
cmpwi 0,r11,0
bne 7f
#endif /* CONFIG_PPC_CHRP */
EXCEPTION_PROLOG_1
7: EXCEPTION_PROLOG_2
addi r3,r1,STACK_FRAME_OVERHEAD
#ifdef CONFIG_PPC_CHRP
mfspr r4,SPRN_SPRG2
cmpwi cr1,r4,0
bne cr1,1f
#endif
EXC_XFER_STD(0x200, machine_check_exception)
#ifdef CONFIG_PPC_CHRP
1: b machine_check_in_rtas
#endif
/* Data access exception. */
. = 0x300
DataAccess:
EXCEPTION_PROLOG
mfspr r10,SPRN_DSISR
stw r10,_DSISR(r11)
andis. r0,r10,0xa470 /* weird error? */
bne 1f /* if not, try to put a PTE */
mfspr r4,SPRN_DAR /* into the hash table */
rlwinm r3,r10,32-15,21,21 /* DSISR_STORE -> _PAGE_RW */
bl hash_page
1: lwz r5,_DSISR(r11) /* get DSISR value */
mfspr r4,SPRN_DAR
EXC_XFER_EE_LITE(0x300, handle_page_fault)
/* Instruction access exception. */
. = 0x400
InstructionAccess:
EXCEPTION_PROLOG
andis. r0,r9,0x4000 /* no pte found? */
beq 1f /* if so, try to put a PTE */
li r3,0 /* into the hash table */
mr r4,r12 /* SRR0 is fault address */
bl hash_page
1: mr r4,r12
mr r5,r9
EXC_XFER_EE_LITE(0x400, handle_page_fault)
/* External interrupt */
EXCEPTION(0x500, HardwareInterrupt, do_IRQ, EXC_XFER_LITE)
/* Alignment exception */
. = 0x600
Alignment:
EXCEPTION_PROLOG
mfspr r4,SPRN_DAR
stw r4,_DAR(r11)
mfspr r5,SPRN_DSISR
stw r5,_DSISR(r11)
addi r3,r1,STACK_FRAME_OVERHEAD
EXC_XFER_EE(0x600, alignment_exception)
/* Program check exception */
EXCEPTION(0x700, ProgramCheck, program_check_exception, EXC_XFER_STD)
/* Floating-point unavailable */
. = 0x800
FPUnavailable:
BEGIN_FTR_SECTION
/*
* Certain Freescale cores don't have a FPU and treat fp instructions
* as a FP Unavailable exception. Redirect to illegal/emulation handling.
*/
b ProgramCheck
END_FTR_SECTION_IFSET(CPU_FTR_FPU_UNAVAILABLE)
EXCEPTION_PROLOG
beq 1f
bl load_up_fpu /* if from user, just load it up */
b fast_exception_return
1: addi r3,r1,STACK_FRAME_OVERHEAD
EXC_XFER_EE_LITE(0x800, kernel_fp_unavailable_exception)
/* Decrementer */
EXCEPTION(0x900, Decrementer, timer_interrupt, EXC_XFER_LITE)
EXCEPTION(0xa00, Trap_0a, unknown_exception, EXC_XFER_EE)
EXCEPTION(0xb00, Trap_0b, unknown_exception, EXC_XFER_EE)
/* System call */
. = 0xc00
SystemCall:
EXCEPTION_PROLOG
EXC_XFER_EE_LITE(0xc00, DoSyscall)
/* Single step - not used on 601 */
EXCEPTION(0xd00, SingleStep, single_step_exception, EXC_XFER_STD)
EXCEPTION(0xe00, Trap_0e, unknown_exception, EXC_XFER_EE)
/*
* The Altivec unavailable trap is at 0x0f20. Foo.
* We effectively remap it to 0x3000.
* We include an altivec unavailable exception vector even if
* not configured for Altivec, so that you can't panic a
* non-altivec kernel running on a machine with altivec just
* by executing an altivec instruction.
*/
. = 0xf00
b PerformanceMonitor
. = 0xf20
b AltiVecUnavailable
/*
* Handle TLB miss for instruction on 603/603e.
* Note: we get an alternate set of r0 - r3 to use automatically.
*/
. = 0x1000
InstructionTLBMiss:
/*
* r0: scratch
* r1: linux style pte ( later becomes ppc hardware pte )
* r2: ptr to linux-style pte
* r3: scratch
*/
/* Get PTE (linux-style) and check access */
mfspr r3,SPRN_IMISS
lis r1,PAGE_OFFSET@h /* check if kernel address */
cmplw 0,r1,r3
mfspr r2,SPRN_SPRG3
li r1,_PAGE_USER|_PAGE_PRESENT /* low addresses tested as user */
lwz r2,PGDIR(r2)
bge- 112f
mfspr r2,SPRN_SRR1 /* and MSR_PR bit from SRR1 */
rlwimi r1,r2,32-12,29,29 /* shift MSR_PR to _PAGE_USER posn */
lis r2,swapper_pg_dir@ha /* if kernel address, use */
addi r2,r2,swapper_pg_dir@l /* kernel page table */
112: tophys(r2,r2)
rlwimi r2,r3,12,20,29 /* insert top 10 bits of address */
lwz r2,0(r2) /* get pmd entry */
rlwinm. r2,r2,0,0,19 /* extract address of pte page */
beq- InstructionAddressInvalid /* return if no mapping */
rlwimi r2,r3,22,20,29 /* insert next 10 bits of address */
lwz r0,0(r2) /* get linux-style pte */
andc. r1,r1,r0 /* check access & ~permission */
bne- InstructionAddressInvalid /* return if access not permitted */
ori r0,r0,_PAGE_ACCESSED /* set _PAGE_ACCESSED in pte */
/*
* NOTE! We are assuming this is not an SMP system, otherwise
* we would need to update the pte atomically with lwarx/stwcx.
*/
stw r0,0(r2) /* update PTE (accessed bit) */
/* Convert linux-style PTE to low word of PPC-style PTE */
rlwinm r1,r0,32-10,31,31 /* _PAGE_RW -> PP lsb */
rlwinm r2,r0,32-7,31,31 /* _PAGE_DIRTY -> PP lsb */
and r1,r1,r2 /* writable if _RW and _DIRTY */
rlwimi r0,r0,32-1,30,30 /* _PAGE_USER -> PP msb */
rlwimi r0,r0,32-1,31,31 /* _PAGE_USER -> PP lsb */
ori r1,r1,0xe04 /* clear out reserved bits */
andc r1,r0,r1 /* PP = user? (rw&dirty? 2: 3): 0 */
BEGIN_FTR_SECTION
rlwinm r1,r1,0,~_PAGE_COHERENT /* clear M (coherence not required) */
END_FTR_SECTION_IFCLR(CPU_FTR_NEED_COHERENT)
mtspr SPRN_RPA,r1
tlbli r3
mfspr r3,SPRN_SRR1 /* Need to restore CR0 */
mtcrf 0x80,r3
rfi
InstructionAddressInvalid:
mfspr r3,SPRN_SRR1
rlwinm r1,r3,9,6,6 /* Get load/store bit */
addis r1,r1,0x2000
mtspr SPRN_DSISR,r1 /* (shouldn't be needed) */
andi. r2,r3,0xFFFF /* Clear upper bits of SRR1 */
or r2,r2,r1
mtspr SPRN_SRR1,r2
mfspr r1,SPRN_IMISS /* Get failing address */
rlwinm. r2,r2,0,31,31 /* Check for little endian access */
rlwimi r2,r2,1,30,30 /* change 1 -> 3 */
xor r1,r1,r2
mtspr SPRN_DAR,r1 /* Set fault address */
mfmsr r0 /* Restore "normal" registers */
xoris r0,r0,MSR_TGPR>>16
mtcrf 0x80,r3 /* Restore CR0 */
mtmsr r0
b InstructionAccess
/*
* Handle TLB miss for DATA Load operation on 603/603e
*/
. = 0x1100
DataLoadTLBMiss:
/*
* r0: scratch
* r1: linux style pte ( later becomes ppc hardware pte )
* r2: ptr to linux-style pte
* r3: scratch
*/
/* Get PTE (linux-style) and check access */
mfspr r3,SPRN_DMISS
lis r1,PAGE_OFFSET@h /* check if kernel address */
cmplw 0,r1,r3
mfspr r2,SPRN_SPRG3
li r1,_PAGE_USER|_PAGE_PRESENT /* low addresses tested as user */
lwz r2,PGDIR(r2)
bge- 112f
mfspr r2,SPRN_SRR1 /* and MSR_PR bit from SRR1 */
rlwimi r1,r2,32-12,29,29 /* shift MSR_PR to _PAGE_USER posn */
lis r2,swapper_pg_dir@ha /* if kernel address, use */
addi r2,r2,swapper_pg_dir@l /* kernel page table */
112: tophys(r2,r2)
rlwimi r2,r3,12,20,29 /* insert top 10 bits of address */
lwz r2,0(r2) /* get pmd entry */
rlwinm. r2,r2,0,0,19 /* extract address of pte page */
beq- DataAddressInvalid /* return if no mapping */
rlwimi r2,r3,22,20,29 /* insert next 10 bits of address */
lwz r0,0(r2) /* get linux-style pte */
andc. r1,r1,r0 /* check access & ~permission */
bne- DataAddressInvalid /* return if access not permitted */
ori r0,r0,_PAGE_ACCESSED /* set _PAGE_ACCESSED in pte */
/*
* NOTE! We are assuming this is not an SMP system, otherwise
* we would need to update the pte atomically with lwarx/stwcx.
*/
stw r0,0(r2) /* update PTE (accessed bit) */
/* Convert linux-style PTE to low word of PPC-style PTE */
rlwinm r1,r0,32-10,31,31 /* _PAGE_RW -> PP lsb */
rlwinm r2,r0,32-7,31,31 /* _PAGE_DIRTY -> PP lsb */
and r1,r1,r2 /* writable if _RW and _DIRTY */
rlwimi r0,r0,32-1,30,30 /* _PAGE_USER -> PP msb */
rlwimi r0,r0,32-1,31,31 /* _PAGE_USER -> PP lsb */
ori r1,r1,0xe04 /* clear out reserved bits */
andc r1,r0,r1 /* PP = user? (rw&dirty? 2: 3): 0 */
BEGIN_FTR_SECTION
rlwinm r1,r1,0,~_PAGE_COHERENT /* clear M (coherence not required) */
END_FTR_SECTION_IFCLR(CPU_FTR_NEED_COHERENT)
mtspr SPRN_RPA,r1
mfspr r2,SPRN_SRR1 /* Need to restore CR0 */
mtcrf 0x80,r2
BEGIN_MMU_FTR_SECTION
li r0,1
mfspr r1,SPRN_SPRG4
rlwinm r2,r3,20,27,31 /* Get Address bits 15:19 */
slw r0,r0,r2
xor r1,r0,r1
srw r0,r1,r2
mtspr SPRN_SPRG4,r1
mfspr r2,SPRN_SRR1
rlwimi r2,r0,31-14,14,14
mtspr SPRN_SRR1,r2
END_MMU_FTR_SECTION_IFSET(MMU_FTR_NEED_DTLB_SW_LRU)
tlbld r3
rfi
DataAddressInvalid:
mfspr r3,SPRN_SRR1
rlwinm r1,r3,9,6,6 /* Get load/store bit */
addis r1,r1,0x2000
mtspr SPRN_DSISR,r1
andi. r2,r3,0xFFFF /* Clear upper bits of SRR1 */
mtspr SPRN_SRR1,r2
mfspr r1,SPRN_DMISS /* Get failing address */
rlwinm. r2,r2,0,31,31 /* Check for little endian access */
beq 20f /* Jump if big endian */
xori r1,r1,3
20: mtspr SPRN_DAR,r1 /* Set fault address */
mfmsr r0 /* Restore "normal" registers */
xoris r0,r0,MSR_TGPR>>16
mtcrf 0x80,r3 /* Restore CR0 */
mtmsr r0
b DataAccess
/*
* Handle TLB miss for DATA Store on 603/603e
*/
. = 0x1200
DataStoreTLBMiss:
/*
* r0: scratch
* r1: linux style pte ( later becomes ppc hardware pte )
* r2: ptr to linux-style pte
* r3: scratch
*/
/* Get PTE (linux-style) and check access */
mfspr r3,SPRN_DMISS
lis r1,PAGE_OFFSET@h /* check if kernel address */
cmplw 0,r1,r3
mfspr r2,SPRN_SPRG3
li r1,_PAGE_RW|_PAGE_USER|_PAGE_PRESENT /* access flags */
lwz r2,PGDIR(r2)
bge- 112f
mfspr r2,SPRN_SRR1 /* and MSR_PR bit from SRR1 */
rlwimi r1,r2,32-12,29,29 /* shift MSR_PR to _PAGE_USER posn */
lis r2,swapper_pg_dir@ha /* if kernel address, use */
addi r2,r2,swapper_pg_dir@l /* kernel page table */
112: tophys(r2,r2)
rlwimi r2,r3,12,20,29 /* insert top 10 bits of address */
lwz r2,0(r2) /* get pmd entry */
rlwinm. r2,r2,0,0,19 /* extract address of pte page */
beq- DataAddressInvalid /* return if no mapping */
rlwimi r2,r3,22,20,29 /* insert next 10 bits of address */
lwz r0,0(r2) /* get linux-style pte */
andc. r1,r1,r0 /* check access & ~permission */
bne- DataAddressInvalid /* return if access not permitted */
ori r0,r0,_PAGE_ACCESSED|_PAGE_DIRTY
/*
* NOTE! We are assuming this is not an SMP system, otherwise
* we would need to update the pte atomically with lwarx/stwcx.
*/
stw r0,0(r2) /* update PTE (accessed/dirty bits) */
/* Convert linux-style PTE to low word of PPC-style PTE */
rlwimi r0,r0,32-1,30,30 /* _PAGE_USER -> PP msb */
li r1,0xe05 /* clear out reserved bits & PP lsb */
andc r1,r0,r1 /* PP = user? 2: 0 */
BEGIN_FTR_SECTION
rlwinm r1,r1,0,~_PAGE_COHERENT /* clear M (coherence not required) */
END_FTR_SECTION_IFCLR(CPU_FTR_NEED_COHERENT)
mtspr SPRN_RPA,r1
mfspr r2,SPRN_SRR1 /* Need to restore CR0 */
mtcrf 0x80,r2
BEGIN_MMU_FTR_SECTION
li r0,1
mfspr r1,SPRN_SPRG4
rlwinm r2,r3,20,27,31 /* Get Address bits 15:19 */
slw r0,r0,r2
xor r1,r0,r1
srw r0,r1,r2
mtspr SPRN_SPRG4,r1
mfspr r2,SPRN_SRR1
rlwimi r2,r0,31-14,14,14
mtspr SPRN_SRR1,r2
END_MMU_FTR_SECTION_IFSET(MMU_FTR_NEED_DTLB_SW_LRU)
tlbld r3
rfi
#ifndef CONFIG_ALTIVEC
#define altivec_assist_exception unknown_exception
#endif
EXCEPTION(0x1300, Trap_13, instruction_breakpoint_exception, EXC_XFER_EE)
EXCEPTION(0x1400, SMI, SMIException, EXC_XFER_EE)
EXCEPTION(0x1500, Trap_15, unknown_exception, EXC_XFER_EE)
EXCEPTION(0x1600, Trap_16, altivec_assist_exception, EXC_XFER_EE)
EXCEPTION(0x1700, Trap_17, TAUException, EXC_XFER_STD)
EXCEPTION(0x1800, Trap_18, unknown_exception, EXC_XFER_EE)
EXCEPTION(0x1900, Trap_19, unknown_exception, EXC_XFER_EE)
EXCEPTION(0x1a00, Trap_1a, unknown_exception, EXC_XFER_EE)
EXCEPTION(0x1b00, Trap_1b, unknown_exception, EXC_XFER_EE)
EXCEPTION(0x1c00, Trap_1c, unknown_exception, EXC_XFER_EE)
EXCEPTION(0x1d00, Trap_1d, unknown_exception, EXC_XFER_EE)
EXCEPTION(0x1e00, Trap_1e, unknown_exception, EXC_XFER_EE)
EXCEPTION(0x1f00, Trap_1f, unknown_exception, EXC_XFER_EE)
EXCEPTION(0x2000, RunMode, RunModeException, EXC_XFER_EE)
EXCEPTION(0x2100, Trap_21, unknown_exception, EXC_XFER_EE)
EXCEPTION(0x2200, Trap_22, unknown_exception, EXC_XFER_EE)
EXCEPTION(0x2300, Trap_23, unknown_exception, EXC_XFER_EE)
EXCEPTION(0x2400, Trap_24, unknown_exception, EXC_XFER_EE)
EXCEPTION(0x2500, Trap_25, unknown_exception, EXC_XFER_EE)
EXCEPTION(0x2600, Trap_26, unknown_exception, EXC_XFER_EE)
EXCEPTION(0x2700, Trap_27, unknown_exception, EXC_XFER_EE)
EXCEPTION(0x2800, Trap_28, unknown_exception, EXC_XFER_EE)
EXCEPTION(0x2900, Trap_29, unknown_exception, EXC_XFER_EE)
EXCEPTION(0x2a00, Trap_2a, unknown_exception, EXC_XFER_EE)
EXCEPTION(0x2b00, Trap_2b, unknown_exception, EXC_XFER_EE)
EXCEPTION(0x2c00, Trap_2c, unknown_exception, EXC_XFER_EE)
EXCEPTION(0x2d00, Trap_2d, unknown_exception, EXC_XFER_EE)
EXCEPTION(0x2e00, Trap_2e, unknown_exception, EXC_XFER_EE)
EXCEPTION(0x2f00, MOLTrampoline, unknown_exception, EXC_XFER_EE_LITE)
.globl mol_trampoline
.set mol_trampoline, i0x2f00
. = 0x3000
AltiVecUnavailable:
EXCEPTION_PROLOG
#ifdef CONFIG_ALTIVEC
beq 1f
bl load_up_altivec /* if from user, just load it up */
b fast_exception_return
#endif /* CONFIG_ALTIVEC */
1: addi r3,r1,STACK_FRAME_OVERHEAD
EXC_XFER_EE_LITE(0xf20, altivec_unavailable_exception)
PerformanceMonitor:
EXCEPTION_PROLOG
addi r3,r1,STACK_FRAME_OVERHEAD
EXC_XFER_STD(0xf00, performance_monitor_exception)
/*
* This code is jumped to from the startup code to copy
* the kernel image to physical address PHYSICAL_START.
*/
relocate_kernel:
addis r9,r26,klimit@ha /* fetch klimit */
lwz r25,klimit@l(r9)
addis r25,r25,-KERNELBASE@h
lis r3,PHYSICAL_START@h /* Destination base address */
li r6,0 /* Destination offset */
li r5,0x4000 /* # bytes of memory to copy */
bl copy_and_flush /* copy the first 0x4000 bytes */
addi r0,r3,4f@l /* jump to the address of 4f */
mtctr r0 /* in copy and do the rest. */
bctr /* jump to the copy */
4: mr r5,r25
bl copy_and_flush /* copy the rest */
b turn_on_mmu
/*
* 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.
*/
_ENTRY(copy_and_flush)
addi r5,r5,-4
addi r6,r6,-4
4: li r0,L1_CACHE_BYTES/4
mtctr r0
3: addi r6,r6,4 /* copy a cache line */
lwzx r0,r6,r4
stwx r0,r6,r3
bdnz 3b
dcbst r6,r3 /* write it to memory */
sync
icbi r6,r3 /* flush the icache line */
cmplw 0,r6,r5
blt 4b
sync /* additional sync needed on g4 */
isync
addi r5,r5,4
addi r6,r6,4
blr
#ifdef CONFIG_SMP
#ifdef CONFIG_GEMINI
.globl __secondary_start_gemini
__secondary_start_gemini:
mfspr r4,SPRN_HID0
ori r4,r4,HID0_ICFI
li r3,0
ori r3,r3,HID0_ICE
andc r4,r4,r3
mtspr SPRN_HID0,r4
sync
b __secondary_start
#endif /* CONFIG_GEMINI */
.globl __secondary_start_mpc86xx
__secondary_start_mpc86xx:
mfspr r3, SPRN_PIR
stw r3, __secondary_hold_acknowledge@l(0)
mr r24, r3 /* cpu # */
b __secondary_start
.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:
/* on powersurge, we come in here with IR=0 and DR=1, and DBAT 0
set to map the 0xf0000000 - 0xffffffff region */
mfmsr r0
rlwinm r0,r0,0,28,26 /* clear DR (0x10) */
SYNC
mtmsr r0
isync
.globl __secondary_start
__secondary_start:
/* Copy some CPU settings from CPU 0 */
bl __restore_cpu_setup
lis r3,-KERNELBASE@h
mr r4,r24
bl call_setup_cpu /* Call setup_cpu for this CPU */
#ifdef CONFIG_6xx
lis r3,-KERNELBASE@h
bl init_idle_6xx
#endif /* CONFIG_6xx */
/* get current_thread_info and current */
lis r1,secondary_ti@ha
tophys(r1,r1)
lwz r1,secondary_ti@l(r1)
tophys(r2,r1)
lwz r2,TI_TASK(r2)
/* stack */
addi r1,r1,THREAD_SIZE-STACK_FRAME_OVERHEAD
li r0,0
tophys(r3,r1)
stw r0,0(r3)
/* load up the MMU */
bl load_up_mmu
/* ptr to phys current thread */
tophys(r4,r2)
addi r4,r4,THREAD /* phys address of our thread_struct */
CLR_TOP32(r4)
mtspr SPRN_SPRG3,r4
li r3,0
mtspr SPRN_SPRG2,r3 /* 0 => not in RTAS */
/* enable MMU and jump to start_secondary */
li r4,MSR_KERNEL
FIX_SRR1(r4,r5)
lis r3,start_secondary@h
ori r3,r3,start_secondary@l
mtspr SPRN_SRR0,r3
mtspr SPRN_SRR1,r4
SYNC
RFI
#endif /* CONFIG_SMP */
/*
* Those generic dummy functions are kept for CPUs not
* included in CONFIG_6xx
*/
#if !defined(CONFIG_6xx)
_ENTRY(__save_cpu_setup)
blr
_ENTRY(__restore_cpu_setup)
blr
#endif /* !defined(CONFIG_6xx) */
/*
* Load stuff into the MMU. Intended to be called with
* IR=0 and DR=0.
*/
load_up_mmu:
sync /* Force all PTE updates to finish */
isync
tlbia /* Clear all TLB entries */
sync /* wait for tlbia/tlbie to finish */
TLBSYNC /* ... on all CPUs */
/* Load the SDR1 register (hash table base & size) */
lis r6,_SDR1@ha
tophys(r6,r6)
lwz r6,_SDR1@l(r6)
mtspr SPRN_SDR1,r6
li r0,16 /* load up segment register values */
mtctr r0 /* for context 0 */
lis r3,0x2000 /* Ku = 1, VSID = 0 */
li r4,0
3: mtsrin r3,r4
addi r3,r3,0x111 /* increment VSID */
addis r4,r4,0x1000 /* address of next segment */
bdnz 3b
/* Load the BAT registers with the values set up by MMU_init.
MMU_init takes care of whether we're on a 601 or not. */
mfpvr r3
srwi r3,r3,16
cmpwi r3,1
lis r3,BATS@ha
addi r3,r3,BATS@l
tophys(r3,r3)
LOAD_BAT(0,r3,r4,r5)
LOAD_BAT(1,r3,r4,r5)
LOAD_BAT(2,r3,r4,r5)
LOAD_BAT(3,r3,r4,r5)
BEGIN_MMU_FTR_SECTION
LOAD_BAT(4,r3,r4,r5)
LOAD_BAT(5,r3,r4,r5)
LOAD_BAT(6,r3,r4,r5)
LOAD_BAT(7,r3,r4,r5)
END_MMU_FTR_SECTION_IFSET(MMU_FTR_USE_HIGH_BATS)
blr
/*
* This is where the main kernel code starts.
*/
start_here:
/* ptr to current */
lis r2,init_task@h
ori r2,r2,init_task@l
/* Set up for using our exception vectors */
/* ptr to phys current thread */
tophys(r4,r2)
addi r4,r4,THREAD /* init task's THREAD */
CLR_TOP32(r4)
mtspr SPRN_SPRG3,r4
li r3,0
mtspr SPRN_SPRG2,r3 /* 0 => not in RTAS */
/* stack */
lis r1,init_thread_union@ha
addi r1,r1,init_thread_union@l
li r0,0
stwu r0,THREAD_SIZE-STACK_FRAME_OVERHEAD(r1)
/*
* Do early platform-specific initialization,
* and set up the MMU.
*/
mr r3,r31
mr r4,r30
bl machine_init
bl __save_cpu_setup
bl MMU_init
/*
* Go back to running unmapped so we can load up new values
* for SDR1 (hash table pointer) and the segment registers
* and change to using our exception vectors.
*/
lis r4,2f@h
ori r4,r4,2f@l
tophys(r4,r4)
li r3,MSR_KERNEL & ~(MSR_IR|MSR_DR)
FIX_SRR1(r3,r5)
mtspr SPRN_SRR0,r4
mtspr SPRN_SRR1,r3
SYNC
RFI
/* Load up the kernel context */
2: bl load_up_mmu
#ifdef CONFIG_BDI_SWITCH
/* Add helper information for the Abatron bdiGDB debugger.
* We do this here because we know the mmu is disabled, and
* will be enabled for real in just a few instructions.
*/
lis r5, abatron_pteptrs@h
ori r5, r5, abatron_pteptrs@l
stw r5, 0xf0(r0) /* This much match your Abatron config */
lis r6, swapper_pg_dir@h
ori r6, r6, swapper_pg_dir@l
tophys(r5, r5)
stw r6, 0(r5)
#endif /* CONFIG_BDI_SWITCH */
/* Now turn on the MMU for real! */
li r4,MSR_KERNEL
FIX_SRR1(r4,r5)
lis r3,start_kernel@h
ori r3,r3,start_kernel@l
mtspr SPRN_SRR0,r3
mtspr SPRN_SRR1,r4
SYNC
RFI
/*
* void switch_mmu_context(struct mm_struct *prev, struct mm_struct *next);
*
* Set up the segment registers for a new context.
*/
_ENTRY(switch_mmu_context)
lwz r3,MMCONTEXTID(r4)
cmpwi cr0,r3,0
blt- 4f
mulli r3,r3,897 /* multiply context by skew factor */
rlwinm r3,r3,4,8,27 /* VSID = (context & 0xfffff) << 4 */
addis r3,r3,0x6000 /* Set Ks, Ku bits */
li r0,NUM_USER_SEGMENTS
mtctr r0
#ifdef CONFIG_BDI_SWITCH
/* Context switch the PTE pointer for the Abatron BDI2000.
* The PGDIR is passed as second argument.
*/
lwz r4,MM_PGD(r4)
lis r5, KERNELBASE@h
lwz r5, 0xf0(r5)
stw r4, 0x4(r5)
#endif
li r4,0
isync
3:
mtsrin r3,r4
addi r3,r3,0x111 /* next VSID */
rlwinm r3,r3,0,8,3 /* clear out any overflow from VSID field */
addis r4,r4,0x1000 /* address of next segment */
bdnz 3b
sync
isync
blr
4: trap
EMIT_BUG_ENTRY 4b,__FILE__,__LINE__,0
blr
/*
* An undocumented "feature" of 604e requires that the v bit
* be cleared before changing BAT values.
*
* Also, newer IBM firmware does not clear bat3 and 4 so
* this makes sure it's done.
* -- Cort
*/
clear_bats:
li r10,0
mfspr r9,SPRN_PVR
rlwinm r9,r9,16,16,31 /* r9 = 1 for 601, 4 for 604 */
cmpwi r9, 1
beq 1f
mtspr SPRN_DBAT0U,r10
mtspr SPRN_DBAT0L,r10
mtspr SPRN_DBAT1U,r10
mtspr SPRN_DBAT1L,r10
mtspr SPRN_DBAT2U,r10
mtspr SPRN_DBAT2L,r10
mtspr SPRN_DBAT3U,r10
mtspr SPRN_DBAT3L,r10
1:
mtspr SPRN_IBAT0U,r10
mtspr SPRN_IBAT0L,r10
mtspr SPRN_IBAT1U,r10
mtspr SPRN_IBAT1L,r10
mtspr SPRN_IBAT2U,r10
mtspr SPRN_IBAT2L,r10
mtspr SPRN_IBAT3U,r10
mtspr SPRN_IBAT3L,r10
BEGIN_MMU_FTR_SECTION
/* Here's a tweak: at this point, CPU setup have
* not been called yet, so HIGH_BAT_EN may not be
* set in HID0 for the 745x processors. However, it
* seems that doesn't affect our ability to actually
* write to these SPRs.
*/
mtspr SPRN_DBAT4U,r10
mtspr SPRN_DBAT4L,r10
mtspr SPRN_DBAT5U,r10
mtspr SPRN_DBAT5L,r10
mtspr SPRN_DBAT6U,r10
mtspr SPRN_DBAT6L,r10
mtspr SPRN_DBAT7U,r10
mtspr SPRN_DBAT7L,r10
mtspr SPRN_IBAT4U,r10
mtspr SPRN_IBAT4L,r10
mtspr SPRN_IBAT5U,r10
mtspr SPRN_IBAT5L,r10
mtspr SPRN_IBAT6U,r10
mtspr SPRN_IBAT6L,r10
mtspr SPRN_IBAT7U,r10
mtspr SPRN_IBAT7L,r10
END_MMU_FTR_SECTION_IFSET(MMU_FTR_USE_HIGH_BATS)
blr
flush_tlbs:
lis r10, 0x40
1: addic. r10, r10, -0x1000
tlbie r10
bgt 1b
sync
blr
mmu_off:
addi r4, r3, __after_mmu_off - _start
mfmsr r3
andi. r0,r3,MSR_DR|MSR_IR /* MMU enabled? */
beqlr
andc r3,r3,r0
mtspr SPRN_SRR0,r4
mtspr SPRN_SRR1,r3
sync
RFI
/*
* On 601, we use 3 BATs to map up to 24M of RAM at _PAGE_OFFSET
* (we keep one for debugging) and on others, we use one 256M BAT.
*/
initial_bats:
lis r11,PAGE_OFFSET@h
mfspr r9,SPRN_PVR
rlwinm r9,r9,16,16,31 /* r9 = 1 for 601, 4 for 604 */
cmpwi 0,r9,1
bne 4f
ori r11,r11,4 /* set up BAT registers for 601 */
li r8,0x7f /* valid, block length = 8MB */
mtspr SPRN_IBAT0U,r11 /* N.B. 601 has valid bit in */
mtspr SPRN_IBAT0L,r8 /* lower BAT register */
addis r11,r11,0x800000@h
addis r8,r8,0x800000@h
mtspr SPRN_IBAT1U,r11
mtspr SPRN_IBAT1L,r8
addis r11,r11,0x800000@h
addis r8,r8,0x800000@h
mtspr SPRN_IBAT2U,r11
mtspr SPRN_IBAT2L,r8
isync
blr
4: tophys(r8,r11)
#ifdef CONFIG_SMP
ori r8,r8,0x12 /* R/W access, M=1 */
#else
ori r8,r8,2 /* R/W access */
#endif /* CONFIG_SMP */
ori r11,r11,BL_256M<<2|0x2 /* set up BAT registers for 604 */
mtspr SPRN_DBAT0L,r8 /* N.B. 6xx (not 601) have valid */
mtspr SPRN_DBAT0U,r11 /* bit in upper BAT register */
mtspr SPRN_IBAT0L,r8
mtspr SPRN_IBAT0U,r11
isync
blr
#ifdef CONFIG_BOOTX_TEXT
setup_disp_bat:
/*
* setup the display bat prepared for us in prom.c
*/
mflr r8
bl reloc_offset
mtlr r8
addis r8,r3,disp_BAT@ha
addi r8,r8,disp_BAT@l
cmpwi cr0,r8,0
beqlr
lwz r11,0(r8)
lwz r8,4(r8)
mfspr r9,SPRN_PVR
rlwinm r9,r9,16,16,31 /* r9 = 1 for 601, 4 for 604 */
cmpwi 0,r9,1
beq 1f
mtspr SPRN_DBAT3L,r8
mtspr SPRN_DBAT3U,r11
blr
1: mtspr SPRN_IBAT3L,r8
mtspr SPRN_IBAT3U,r11
blr
#endif /* CONFIG_BOOTX_TEXT */
#ifdef CONFIG_PPC_EARLY_DEBUG_CPM
setup_cpm_bat:
lis r8, 0xf000
ori r8, r8, 0x002a
mtspr SPRN_DBAT1L, r8
lis r11, 0xf000
ori r11, r11, (BL_1M << 2) | 2
mtspr SPRN_DBAT1U, r11
blr
#endif
#ifdef CONFIG_8260
/* Jump into the system reset for the rom.
* We first disable the MMU, and then jump to the ROM reset address.
*
* r3 is the board info structure, r4 is the location for starting.
* I use this for building a small kernel that can load other kernels,
* rather than trying to write or rely on a rom monitor that can tftp load.
*/
.globl m8260_gorom
m8260_gorom:
mfmsr r0
rlwinm r0,r0,0,17,15 /* clear MSR_EE in r0 */
sync
mtmsr r0
sync
mfspr r11, SPRN_HID0
lis r10, 0
ori r10,r10,HID0_ICE|HID0_DCE
andc r11, r11, r10
mtspr SPRN_HID0, r11
isync
li r5, MSR_ME|MSR_RI
lis r6,2f@h
addis r6,r6,-KERNELBASE@h
ori r6,r6,2f@l
mtspr SPRN_SRR0,r6
mtspr SPRN_SRR1,r5
isync
sync
rfi
2:
mtlr r4
blr
#endif
/*
* We put a few things here that have to be page-aligned.
* This stuff goes at the beginning of the data segment,
* which is page-aligned.
*/
.data
.globl sdata
sdata:
.globl empty_zero_page
empty_zero_page:
.space 4096
.globl swapper_pg_dir
swapper_pg_dir:
.space PGD_TABLE_SIZE
.globl intercept_table
intercept_table:
.long 0, 0, i0x200, i0x300, i0x400, 0, i0x600, i0x700
.long i0x800, 0, 0, 0, 0, i0xd00, 0, 0
.long 0, 0, 0, i0x1300, 0, 0, 0, 0
.long 0, 0, 0, 0, 0, 0, 0, 0
.long 0, 0, 0, 0, 0, 0, 0, 0
.long 0, 0, 0, 0, 0, 0, 0, 0
/* Room for two PTE pointers, usually the kernel and current user pointers
* to their respective root page table.
*/
abatron_pteptrs:
.space 8
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