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Diffstat (limited to 'arch/powerpc/kernel/head_44x.S')
| -rw-r--r-- | arch/powerpc/kernel/head_44x.S | 1275 |
1 files changed, 1275 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/head_44x.S b/arch/powerpc/kernel/head_44x.S new file mode 100644 index 000000000..8e36718f3 --- /dev/null +++ b/arch/powerpc/kernel/head_44x.S @@ -0,0 +1,1275 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * Kernel execution entry point code. + * + * Copyright (c) 1995-1996 Gary Thomas <gdt@linuxppc.org> + * Initial PowerPC version. + * Copyright (c) 1996 Cort Dougan <cort@cs.nmt.edu> + * Rewritten for PReP + * Copyright (c) 1996 Paul Mackerras <paulus@cs.anu.edu.au> + * Low-level exception handers, MMU support, and rewrite. + * Copyright (c) 1997 Dan Malek <dmalek@jlc.net> + * PowerPC 8xx modifications. + * Copyright (c) 1998-1999 TiVo, Inc. + * PowerPC 403GCX modifications. + * Copyright (c) 1999 Grant Erickson <grant@lcse.umn.edu> + * PowerPC 403GCX/405GP modifications. + * Copyright 2000 MontaVista Software Inc. + * PPC405 modifications + * PowerPC 403GCX/405GP modifications. + * Author: MontaVista Software, Inc. + * frank_rowand@mvista.com or source@mvista.com + * debbie_chu@mvista.com + * Copyright 2002-2005 MontaVista Software, Inc. + * PowerPC 44x support, Matt Porter <mporter@kernel.crashing.org> + */ + +#include <linux/init.h> +#include <linux/pgtable.h> +#include <asm/processor.h> +#include <asm/page.h> +#include <asm/mmu.h> +#include <asm/cputable.h> +#include <asm/thread_info.h> +#include <asm/ppc_asm.h> +#include <asm/asm-offsets.h> +#include <asm/ptrace.h> +#include <asm/synch.h> +#include <asm/export.h> +#include <asm/code-patching-asm.h> +#include "head_booke.h" + + +/* As with the other PowerPC ports, it is expected that when code + * execution begins here, the following registers contain valid, yet + * optional, information: + * + * r3 - Board info structure pointer (DRAM, frequency, MAC address, etc.) + * r4 - Starting address of the init RAM disk + * r5 - Ending address of the init RAM disk + * r6 - Start of kernel command line string (e.g. "mem=128") + * r7 - End of kernel command line string + * + */ + __HEAD +_ENTRY(_stext); +_ENTRY(_start); + /* + * Reserve a word at a fixed location to store the address + * of abatron_pteptrs + */ + nop + mr r31,r3 /* save device tree ptr */ + li r24,0 /* CPU number */ + +#ifdef CONFIG_RELOCATABLE +/* + * Relocate ourselves to the current runtime address. + * This is called only by the Boot CPU. + * "relocate" is called with our current runtime virutal + * address. + * r21 will be loaded with the physical runtime address of _stext + */ + bl 0f /* Get our runtime address */ +0: mflr r21 /* Make it accessible */ + addis r21,r21,(_stext - 0b)@ha + addi r21,r21,(_stext - 0b)@l /* Get our current runtime base */ + + /* + * We have the runtime (virutal) address of our base. + * We calculate our shift of offset from a 256M page. + * We could map the 256M page we belong to at PAGE_OFFSET and + * get going from there. + */ + lis r4,KERNELBASE@h + ori r4,r4,KERNELBASE@l + rlwinm r6,r21,0,4,31 /* r6 = PHYS_START % 256M */ + rlwinm r5,r4,0,4,31 /* r5 = KERNELBASE % 256M */ + subf r3,r5,r6 /* r3 = r6 - r5 */ + add r3,r4,r3 /* Required Virutal Address */ + + bl relocate +#endif + + bl init_cpu_state + + /* + * This is where the main kernel code starts. + */ + + /* ptr to current */ + lis r2,init_task@h + ori r2,r2,init_task@l + + /* ptr to current thread */ + addi r4,r2,THREAD /* init task's THREAD */ + mtspr SPRN_SPRG_THREAD,r4 + + /* stack */ + lis r1,init_thread_union@h + ori r1,r1,init_thread_union@l + li r0,0 + stwu r0,THREAD_SIZE-STACK_FRAME_OVERHEAD(r1) + + bl early_init + +#ifdef CONFIG_RELOCATABLE + /* + * Relocatable kernel support based on processing of dynamic + * relocation entries. + * + * r25 will contain RPN/ERPN for the start address of memory + * r21 will contain the current offset of _stext + */ + lis r3,kernstart_addr@ha + la r3,kernstart_addr@l(r3) + + /* + * Compute the kernstart_addr. + * kernstart_addr => (r6,r8) + * kernstart_addr & ~0xfffffff => (r6,r7) + */ + rlwinm r6,r25,0,28,31 /* ERPN. Bits 32-35 of Address */ + rlwinm r7,r25,0,0,3 /* RPN - assuming 256 MB page size */ + rlwinm r8,r21,0,4,31 /* r8 = (_stext & 0xfffffff) */ + or r8,r7,r8 /* Compute the lower 32bit of kernstart_addr */ + + /* Store kernstart_addr */ + stw r6,0(r3) /* higher 32bit */ + stw r8,4(r3) /* lower 32bit */ + + /* + * Compute the virt_phys_offset : + * virt_phys_offset = stext.run - kernstart_addr + * + * stext.run = (KERNELBASE & ~0xfffffff) + (kernstart_addr & 0xfffffff) + * When we relocate, we have : + * + * (kernstart_addr & 0xfffffff) = (stext.run & 0xfffffff) + * + * hence: + * virt_phys_offset = (KERNELBASE & ~0xfffffff) - (kernstart_addr & ~0xfffffff) + * + */ + + /* KERNELBASE&~0xfffffff => (r4,r5) */ + li r4, 0 /* higer 32bit */ + lis r5,KERNELBASE@h + rlwinm r5,r5,0,0,3 /* Align to 256M, lower 32bit */ + + /* + * 64bit subtraction. + */ + subfc r5,r7,r5 + subfe r4,r6,r4 + + /* Store virt_phys_offset */ + lis r3,virt_phys_offset@ha + la r3,virt_phys_offset@l(r3) + + stw r4,0(r3) + stw r5,4(r3) + +#elif defined(CONFIG_DYNAMIC_MEMSTART) + /* + * Mapping based, page aligned dynamic kernel loading. + * + * r25 will contain RPN/ERPN for the start address of memory + * + * Add the difference between KERNELBASE and PAGE_OFFSET to the + * start of physical memory to get kernstart_addr. + */ + lis r3,kernstart_addr@ha + la r3,kernstart_addr@l(r3) + + lis r4,KERNELBASE@h + ori r4,r4,KERNELBASE@l + lis r5,PAGE_OFFSET@h + ori r5,r5,PAGE_OFFSET@l + subf r4,r5,r4 + + rlwinm r6,r25,0,28,31 /* ERPN */ + rlwinm r7,r25,0,0,3 /* RPN - assuming 256 MB page size */ + add r7,r7,r4 + + stw r6,0(r3) + stw r7,4(r3) +#endif + +/* + * Decide what sort of machine this is and initialize the MMU. + */ +#ifdef CONFIG_KASAN + bl kasan_early_init +#endif + li r3,0 + mr r4,r31 + bl machine_init + bl MMU_init + + /* Setup PTE pointers for the Abatron bdiGDB */ + lis r6, swapper_pg_dir@h + ori r6, r6, swapper_pg_dir@l + lis r5, abatron_pteptrs@h + ori r5, r5, abatron_pteptrs@l + lis r4, KERNELBASE@h + ori r4, r4, KERNELBASE@l + stw r5, 0(r4) /* Save abatron_pteptrs at a fixed location */ + stw r6, 0(r5) + + /* Clear the Machine Check Syndrome Register */ + li r0,0 + mtspr SPRN_MCSR,r0 + + /* Let's move on */ + lis r4,start_kernel@h + ori r4,r4,start_kernel@l + lis r3,MSR_KERNEL@h + ori r3,r3,MSR_KERNEL@l + mtspr SPRN_SRR0,r4 + mtspr SPRN_SRR1,r3 + rfi /* change context and jump to start_kernel */ + +/* + * Interrupt vector entry code + * + * The Book E MMUs are always on so we don't need to handle + * interrupts in real mode as with previous PPC processors. In + * this case we handle interrupts in the kernel virtual address + * space. + * + * Interrupt vectors are dynamically placed relative to the + * interrupt prefix as determined by the address of interrupt_base. + * The interrupt vectors offsets are programmed using the labels + * for each interrupt vector entry. + * + * Interrupt vectors must be aligned on a 16 byte boundary. + * We align on a 32 byte cache line boundary for good measure. + */ + +interrupt_base: + /* Critical Input Interrupt */ + CRITICAL_EXCEPTION(0x0100, CRITICAL, CriticalInput, unknown_exception) + + /* Machine Check Interrupt */ + CRITICAL_EXCEPTION(0x0200, MACHINE_CHECK, MachineCheck, \ + machine_check_exception) + MCHECK_EXCEPTION(0x0210, MachineCheckA, machine_check_exception) + + /* Data Storage Interrupt */ + DATA_STORAGE_EXCEPTION + + /* Instruction Storage Interrupt */ + INSTRUCTION_STORAGE_EXCEPTION + + /* External Input Interrupt */ + EXCEPTION(0x0500, BOOKE_INTERRUPT_EXTERNAL, ExternalInput, \ + do_IRQ, EXC_XFER_LITE) + + /* Alignment Interrupt */ + ALIGNMENT_EXCEPTION + + /* Program Interrupt */ + PROGRAM_EXCEPTION + + /* Floating Point Unavailable Interrupt */ +#ifdef CONFIG_PPC_FPU + FP_UNAVAILABLE_EXCEPTION +#else + EXCEPTION(0x2010, BOOKE_INTERRUPT_FP_UNAVAIL, \ + FloatingPointUnavailable, unknown_exception, EXC_XFER_STD) +#endif + /* System Call Interrupt */ + START_EXCEPTION(SystemCall) + SYSCALL_ENTRY 0xc00 BOOKE_INTERRUPT_SYSCALL + + /* Auxiliary Processor Unavailable Interrupt */ + EXCEPTION(0x2020, BOOKE_INTERRUPT_AP_UNAVAIL, \ + AuxillaryProcessorUnavailable, unknown_exception, EXC_XFER_STD) + + /* Decrementer Interrupt */ + DECREMENTER_EXCEPTION + + /* Fixed Internal Timer Interrupt */ + /* TODO: Add FIT support */ + EXCEPTION(0x1010, BOOKE_INTERRUPT_FIT, FixedIntervalTimer, \ + unknown_exception, EXC_XFER_STD) + + /* Watchdog Timer Interrupt */ + /* TODO: Add watchdog support */ +#ifdef CONFIG_BOOKE_WDT + CRITICAL_EXCEPTION(0x1020, WATCHDOG, WatchdogTimer, WatchdogException) +#else + CRITICAL_EXCEPTION(0x1020, WATCHDOG, WatchdogTimer, unknown_exception) +#endif + + /* Data TLB Error Interrupt */ + START_EXCEPTION(DataTLBError44x) + mtspr SPRN_SPRG_WSCRATCH0, r10 /* Save some working registers */ + mtspr SPRN_SPRG_WSCRATCH1, r11 + mtspr SPRN_SPRG_WSCRATCH2, r12 + mtspr SPRN_SPRG_WSCRATCH3, r13 + mfcr r11 + mtspr SPRN_SPRG_WSCRATCH4, r11 + mfspr r10, SPRN_DEAR /* Get faulting address */ + + /* If we are faulting a kernel address, we have to use the + * kernel page tables. + */ + lis r11, PAGE_OFFSET@h + cmplw r10, r11 + blt+ 3f + lis r11, swapper_pg_dir@h + ori r11, r11, swapper_pg_dir@l + + mfspr r12,SPRN_MMUCR + rlwinm r12,r12,0,0,23 /* Clear TID */ + + b 4f + + /* Get the PGD for the current thread */ +3: + mfspr r11,SPRN_SPRG_THREAD + lwz r11,PGDIR(r11) + + /* Load PID into MMUCR TID */ + mfspr r12,SPRN_MMUCR + mfspr r13,SPRN_PID /* Get PID */ + rlwimi r12,r13,0,24,31 /* Set TID */ + +4: + mtspr SPRN_MMUCR,r12 + + /* Mask of required permission bits. Note that while we + * do copy ESR:ST to _PAGE_RW position as trying to write + * to an RO page is pretty common, we don't do it with + * _PAGE_DIRTY. We could do it, but it's a fairly rare + * event so I'd rather take the overhead when it happens + * rather than adding an instruction here. We should measure + * whether the whole thing is worth it in the first place + * as we could avoid loading SPRN_ESR completely in the first + * place... + * + * TODO: Is it worth doing that mfspr & rlwimi in the first + * place or can we save a couple of instructions here ? + */ + mfspr r12,SPRN_ESR + li r13,_PAGE_PRESENT|_PAGE_ACCESSED + rlwimi r13,r12,10,30,30 + + /* Load the PTE */ + /* Compute pgdir/pmd offset */ + rlwinm r12, r10, PPC44x_PGD_OFF_SHIFT, PPC44x_PGD_OFF_MASK_BIT, 29 + lwzx r11, r12, r11 /* Get pgd/pmd entry */ + rlwinm. r12, r11, 0, 0, 20 /* Extract pt base address */ + beq 2f /* Bail if no table */ + + /* Compute pte address */ + rlwimi r12, r10, PPC44x_PTE_ADD_SHIFT, PPC44x_PTE_ADD_MASK_BIT, 28 + lwz r11, 0(r12) /* Get high word of pte entry */ + lwz r12, 4(r12) /* Get low word of pte entry */ + + lis r10,tlb_44x_index@ha + + andc. r13,r13,r12 /* Check permission */ + + /* Load the next available TLB index */ + lwz r13,tlb_44x_index@l(r10) + + bne 2f /* Bail if permission mismach */ + + /* Increment, rollover, and store TLB index */ + addi r13,r13,1 + + patch_site 0f, patch__tlb_44x_hwater_D + /* Compare with watermark (instruction gets patched) */ +0: cmpwi 0,r13,1 /* reserve entries */ + ble 5f + li r13,0 +5: + /* Store the next available TLB index */ + stw r13,tlb_44x_index@l(r10) + + /* Re-load the faulting address */ + mfspr r10,SPRN_DEAR + + /* Jump to common tlb load */ + b finish_tlb_load_44x + +2: + /* The bailout. Restore registers to pre-exception conditions + * and call the heavyweights to help us out. + */ + mfspr r11, SPRN_SPRG_RSCRATCH4 + mtcr r11 + mfspr r13, SPRN_SPRG_RSCRATCH3 + mfspr r12, SPRN_SPRG_RSCRATCH2 + mfspr r11, SPRN_SPRG_RSCRATCH1 + mfspr r10, SPRN_SPRG_RSCRATCH0 + b DataStorage + + /* Instruction TLB Error Interrupt */ + /* + * Nearly the same as above, except we get our + * information from different registers and bailout + * to a different point. + */ + START_EXCEPTION(InstructionTLBError44x) + mtspr SPRN_SPRG_WSCRATCH0, r10 /* Save some working registers */ + mtspr SPRN_SPRG_WSCRATCH1, r11 + mtspr SPRN_SPRG_WSCRATCH2, r12 + mtspr SPRN_SPRG_WSCRATCH3, r13 + mfcr r11 + mtspr SPRN_SPRG_WSCRATCH4, r11 + mfspr r10, SPRN_SRR0 /* Get faulting address */ + + /* If we are faulting a kernel address, we have to use the + * kernel page tables. + */ + lis r11, PAGE_OFFSET@h + cmplw r10, r11 + blt+ 3f + lis r11, swapper_pg_dir@h + ori r11, r11, swapper_pg_dir@l + + mfspr r12,SPRN_MMUCR + rlwinm r12,r12,0,0,23 /* Clear TID */ + + b 4f + + /* Get the PGD for the current thread */ +3: + mfspr r11,SPRN_SPRG_THREAD + lwz r11,PGDIR(r11) + + /* Load PID into MMUCR TID */ + mfspr r12,SPRN_MMUCR + mfspr r13,SPRN_PID /* Get PID */ + rlwimi r12,r13,0,24,31 /* Set TID */ + +4: + mtspr SPRN_MMUCR,r12 + + /* Make up the required permissions */ + li r13,_PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_EXEC + + /* Compute pgdir/pmd offset */ + rlwinm r12, r10, PPC44x_PGD_OFF_SHIFT, PPC44x_PGD_OFF_MASK_BIT, 29 + lwzx r11, r12, r11 /* Get pgd/pmd entry */ + rlwinm. r12, r11, 0, 0, 20 /* Extract pt base address */ + beq 2f /* Bail if no table */ + + /* Compute pte address */ + rlwimi r12, r10, PPC44x_PTE_ADD_SHIFT, PPC44x_PTE_ADD_MASK_BIT, 28 + lwz r11, 0(r12) /* Get high word of pte entry */ + lwz r12, 4(r12) /* Get low word of pte entry */ + + lis r10,tlb_44x_index@ha + + andc. r13,r13,r12 /* Check permission */ + + /* Load the next available TLB index */ + lwz r13,tlb_44x_index@l(r10) + + bne 2f /* Bail if permission mismach */ + + /* Increment, rollover, and store TLB index */ + addi r13,r13,1 + + patch_site 0f, patch__tlb_44x_hwater_I + /* Compare with watermark (instruction gets patched) */ +0: cmpwi 0,r13,1 /* reserve entries */ + ble 5f + li r13,0 +5: + /* Store the next available TLB index */ + stw r13,tlb_44x_index@l(r10) + + /* Re-load the faulting address */ + mfspr r10,SPRN_SRR0 + + /* Jump to common TLB load point */ + b finish_tlb_load_44x + +2: + /* The bailout. Restore registers to pre-exception conditions + * and call the heavyweights to help us out. + */ + mfspr r11, SPRN_SPRG_RSCRATCH4 + mtcr r11 + mfspr r13, SPRN_SPRG_RSCRATCH3 + mfspr r12, SPRN_SPRG_RSCRATCH2 + mfspr r11, SPRN_SPRG_RSCRATCH1 + mfspr r10, SPRN_SPRG_RSCRATCH0 + b InstructionStorage + +/* + * Both the instruction and data TLB miss get to this + * point to load the TLB. + * r10 - EA of fault + * r11 - PTE high word value + * r12 - PTE low word value + * r13 - TLB index + * MMUCR - loaded with proper value when we get here + * Upon exit, we reload everything and RFI. + */ +finish_tlb_load_44x: + /* Combine RPN & ERPN an write WS 0 */ + rlwimi r11,r12,0,0,31-PAGE_SHIFT + tlbwe r11,r13,PPC44x_TLB_XLAT + + /* + * Create WS1. This is the faulting address (EPN), + * page size, and valid flag. + */ + li r11,PPC44x_TLB_VALID | PPC44x_TLBE_SIZE + /* Insert valid and page size */ + rlwimi r10,r11,0,PPC44x_PTE_ADD_MASK_BIT,31 + tlbwe r10,r13,PPC44x_TLB_PAGEID /* Write PAGEID */ + + /* And WS 2 */ + li r10,0xf85 /* Mask to apply from PTE */ + rlwimi r10,r12,29,30,30 /* DIRTY -> SW position */ + and r11,r12,r10 /* Mask PTE bits to keep */ + andi. r10,r12,_PAGE_USER /* User page ? */ + beq 1f /* nope, leave U bits empty */ + rlwimi r11,r11,3,26,28 /* yes, copy S bits to U */ +1: tlbwe r11,r13,PPC44x_TLB_ATTRIB /* Write ATTRIB */ + + /* Done...restore registers and get out of here. + */ + mfspr r11, SPRN_SPRG_RSCRATCH4 + mtcr r11 + mfspr r13, SPRN_SPRG_RSCRATCH3 + mfspr r12, SPRN_SPRG_RSCRATCH2 + mfspr r11, SPRN_SPRG_RSCRATCH1 + mfspr r10, SPRN_SPRG_RSCRATCH0 + rfi /* Force context change */ + +/* TLB error interrupts for 476 + */ +#ifdef CONFIG_PPC_47x + START_EXCEPTION(DataTLBError47x) + mtspr SPRN_SPRG_WSCRATCH0,r10 /* Save some working registers */ + mtspr SPRN_SPRG_WSCRATCH1,r11 + mtspr SPRN_SPRG_WSCRATCH2,r12 + mtspr SPRN_SPRG_WSCRATCH3,r13 + mfcr r11 + mtspr SPRN_SPRG_WSCRATCH4,r11 + mfspr r10,SPRN_DEAR /* Get faulting address */ + + /* If we are faulting a kernel address, we have to use the + * kernel page tables. + */ + lis r11,PAGE_OFFSET@h + cmplw cr0,r10,r11 + blt+ 3f + lis r11,swapper_pg_dir@h + ori r11,r11, swapper_pg_dir@l + li r12,0 /* MMUCR = 0 */ + b 4f + + /* Get the PGD for the current thread and setup MMUCR */ +3: mfspr r11,SPRN_SPRG3 + lwz r11,PGDIR(r11) + mfspr r12,SPRN_PID /* Get PID */ +4: mtspr SPRN_MMUCR,r12 /* Set MMUCR */ + + /* Mask of required permission bits. Note that while we + * do copy ESR:ST to _PAGE_RW position as trying to write + * to an RO page is pretty common, we don't do it with + * _PAGE_DIRTY. We could do it, but it's a fairly rare + * event so I'd rather take the overhead when it happens + * rather than adding an instruction here. We should measure + * whether the whole thing is worth it in the first place + * as we could avoid loading SPRN_ESR completely in the first + * place... + * + * TODO: Is it worth doing that mfspr & rlwimi in the first + * place or can we save a couple of instructions here ? + */ + mfspr r12,SPRN_ESR + li r13,_PAGE_PRESENT|_PAGE_ACCESSED + rlwimi r13,r12,10,30,30 + + /* Load the PTE */ + /* Compute pgdir/pmd offset */ + rlwinm r12,r10,PPC44x_PGD_OFF_SHIFT,PPC44x_PGD_OFF_MASK_BIT,29 + lwzx r11,r12,r11 /* Get pgd/pmd entry */ + + /* Word 0 is EPN,V,TS,DSIZ */ + li r12,PPC47x_TLB0_VALID | PPC47x_TLBE_SIZE + rlwimi r10,r12,0,32-PAGE_SHIFT,31 /* Insert valid and page size*/ + li r12,0 + tlbwe r10,r12,0 + + /* XXX can we do better ? Need to make sure tlbwe has established + * latch V bit in MMUCR0 before the PTE is loaded further down */ +#ifdef CONFIG_SMP + isync +#endif + + rlwinm. r12,r11,0,0,20 /* Extract pt base address */ + /* Compute pte address */ + rlwimi r12,r10,PPC44x_PTE_ADD_SHIFT,PPC44x_PTE_ADD_MASK_BIT,28 + beq 2f /* Bail if no table */ + lwz r11,0(r12) /* Get high word of pte entry */ + + /* XXX can we do better ? maybe insert a known 0 bit from r11 into the + * bottom of r12 to create a data dependency... We can also use r10 + * as destination nowadays + */ +#ifdef CONFIG_SMP + lwsync +#endif + lwz r12,4(r12) /* Get low word of pte entry */ + + andc. r13,r13,r12 /* Check permission */ + + /* Jump to common tlb load */ + beq finish_tlb_load_47x + +2: /* The bailout. Restore registers to pre-exception conditions + * and call the heavyweights to help us out. + */ + mfspr r11,SPRN_SPRG_RSCRATCH4 + mtcr r11 + mfspr r13,SPRN_SPRG_RSCRATCH3 + mfspr r12,SPRN_SPRG_RSCRATCH2 + mfspr r11,SPRN_SPRG_RSCRATCH1 + mfspr r10,SPRN_SPRG_RSCRATCH0 + b DataStorage + + /* Instruction TLB Error Interrupt */ + /* + * Nearly the same as above, except we get our + * information from different registers and bailout + * to a different point. + */ + START_EXCEPTION(InstructionTLBError47x) + mtspr SPRN_SPRG_WSCRATCH0,r10 /* Save some working registers */ + mtspr SPRN_SPRG_WSCRATCH1,r11 + mtspr SPRN_SPRG_WSCRATCH2,r12 + mtspr SPRN_SPRG_WSCRATCH3,r13 + mfcr r11 + mtspr SPRN_SPRG_WSCRATCH4,r11 + mfspr r10,SPRN_SRR0 /* Get faulting address */ + + /* If we are faulting a kernel address, we have to use the + * kernel page tables. + */ + lis r11,PAGE_OFFSET@h + cmplw cr0,r10,r11 + blt+ 3f + lis r11,swapper_pg_dir@h + ori r11,r11, swapper_pg_dir@l + li r12,0 /* MMUCR = 0 */ + b 4f + + /* Get the PGD for the current thread and setup MMUCR */ +3: mfspr r11,SPRN_SPRG_THREAD + lwz r11,PGDIR(r11) + mfspr r12,SPRN_PID /* Get PID */ +4: mtspr SPRN_MMUCR,r12 /* Set MMUCR */ + + /* Make up the required permissions */ + li r13,_PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_EXEC + + /* Load PTE */ + /* Compute pgdir/pmd offset */ + rlwinm r12,r10,PPC44x_PGD_OFF_SHIFT,PPC44x_PGD_OFF_MASK_BIT,29 + lwzx r11,r12,r11 /* Get pgd/pmd entry */ + + /* Word 0 is EPN,V,TS,DSIZ */ + li r12,PPC47x_TLB0_VALID | PPC47x_TLBE_SIZE + rlwimi r10,r12,0,32-PAGE_SHIFT,31 /* Insert valid and page size*/ + li r12,0 + tlbwe r10,r12,0 + + /* XXX can we do better ? Need to make sure tlbwe has established + * latch V bit in MMUCR0 before the PTE is loaded further down */ +#ifdef CONFIG_SMP + isync +#endif + + rlwinm. r12,r11,0,0,20 /* Extract pt base address */ + /* Compute pte address */ + rlwimi r12,r10,PPC44x_PTE_ADD_SHIFT,PPC44x_PTE_ADD_MASK_BIT,28 + beq 2f /* Bail if no table */ + + lwz r11,0(r12) /* Get high word of pte entry */ + /* XXX can we do better ? maybe insert a known 0 bit from r11 into the + * bottom of r12 to create a data dependency... We can also use r10 + * as destination nowadays + */ +#ifdef CONFIG_SMP + lwsync +#endif + lwz r12,4(r12) /* Get low word of pte entry */ + + andc. r13,r13,r12 /* Check permission */ + + /* Jump to common TLB load point */ + beq finish_tlb_load_47x + +2: /* The bailout. Restore registers to pre-exception conditions + * and call the heavyweights to help us out. + */ + mfspr r11, SPRN_SPRG_RSCRATCH4 + mtcr r11 + mfspr r13, SPRN_SPRG_RSCRATCH3 + mfspr r12, SPRN_SPRG_RSCRATCH2 + mfspr r11, SPRN_SPRG_RSCRATCH1 + mfspr r10, SPRN_SPRG_RSCRATCH0 + b InstructionStorage + +/* + * Both the instruction and data TLB miss get to this + * point to load the TLB. + * r10 - free to use + * r11 - PTE high word value + * r12 - PTE low word value + * r13 - free to use + * MMUCR - loaded with proper value when we get here + * Upon exit, we reload everything and RFI. + */ +finish_tlb_load_47x: + /* Combine RPN & ERPN an write WS 1 */ + rlwimi r11,r12,0,0,31-PAGE_SHIFT + tlbwe r11,r13,1 + + /* And make up word 2 */ + li r10,0xf85 /* Mask to apply from PTE */ + rlwimi r10,r12,29,30,30 /* DIRTY -> SW position */ + and r11,r12,r10 /* Mask PTE bits to keep */ + andi. r10,r12,_PAGE_USER /* User page ? */ + beq 1f /* nope, leave U bits empty */ + rlwimi r11,r11,3,26,28 /* yes, copy S bits to U */ +1: tlbwe r11,r13,2 + + /* Done...restore registers and get out of here. + */ + mfspr r11, SPRN_SPRG_RSCRATCH4 + mtcr r11 + mfspr r13, SPRN_SPRG_RSCRATCH3 + mfspr r12, SPRN_SPRG_RSCRATCH2 + mfspr r11, SPRN_SPRG_RSCRATCH1 + mfspr r10, SPRN_SPRG_RSCRATCH0 + rfi + +#endif /* CONFIG_PPC_47x */ + + /* Debug Interrupt */ + /* + * This statement needs to exist at the end of the IVPR + * definition just in case you end up taking a debug + * exception within another exception. + */ + DEBUG_CRIT_EXCEPTION + +interrupt_end: + +/* + * Global functions + */ + +/* + * Adjust the machine check IVOR on 440A cores + */ +_GLOBAL(__fixup_440A_mcheck) + li r3,MachineCheckA@l + mtspr SPRN_IVOR1,r3 + sync + blr + +_GLOBAL(set_context) + +#ifdef CONFIG_BDI_SWITCH + /* Context switch the PTE pointer for the Abatron BDI2000. + * The PGDIR is the second parameter. + */ + lis r5, abatron_pteptrs@h + ori r5, r5, abatron_pteptrs@l + stw r4, 0x4(r5) +#endif + mtspr SPRN_PID,r3 + isync /* Force context change */ + blr + +/* + * Init CPU state. This is called at boot time or for secondary CPUs + * to setup initial TLB entries, setup IVORs, etc... + * + */ +_GLOBAL(init_cpu_state) + mflr r22 +#ifdef CONFIG_PPC_47x + /* We use the PVR to differentiate 44x cores from 476 */ + mfspr r3,SPRN_PVR + srwi r3,r3,16 + cmplwi cr0,r3,PVR_476FPE@h + beq head_start_47x + cmplwi cr0,r3,PVR_476@h + beq head_start_47x + cmplwi cr0,r3,PVR_476_ISS@h + beq head_start_47x +#endif /* CONFIG_PPC_47x */ + +/* + * In case the firmware didn't do it, we apply some workarounds + * that are good for all 440 core variants here + */ + mfspr r3,SPRN_CCR0 + rlwinm r3,r3,0,0,27 /* disable icache prefetch */ + isync + mtspr SPRN_CCR0,r3 + isync + sync + +/* + * Set up the initial MMU state for 44x + * + * We are still executing code at the virtual address + * mappings set by the firmware for the base of RAM. + * + * We first invalidate all TLB entries but the one + * we are running from. We then load the KERNELBASE + * mappings so we can begin to use kernel addresses + * natively and so the interrupt vector locations are + * permanently pinned (necessary since Book E + * implementations always have translation enabled). + * + * TODO: Use the known TLB entry we are running from to + * determine which physical region we are located + * in. This can be used to determine where in RAM + * (on a shared CPU system) or PCI memory space + * (on a DRAMless system) we are located. + * For now, we assume a perfect world which means + * we are located at the base of DRAM (physical 0). + */ + +/* + * Search TLB for entry that we are currently using. + * Invalidate all entries but the one we are using. + */ + /* Load our current PID->MMUCR TID and MSR IS->MMUCR STS */ + mfspr r3,SPRN_PID /* Get PID */ + mfmsr r4 /* Get MSR */ + andi. r4,r4,MSR_IS@l /* TS=1? */ + beq wmmucr /* If not, leave STS=0 */ + oris r3,r3,PPC44x_MMUCR_STS@h /* Set STS=1 */ +wmmucr: mtspr SPRN_MMUCR,r3 /* Put MMUCR */ + sync + + bl invstr /* Find our address */ +invstr: mflr r5 /* Make it accessible */ + tlbsx r23,0,r5 /* Find entry we are in */ + li r4,0 /* Start at TLB entry 0 */ + li r3,0 /* Set PAGEID inval value */ +1: cmpw r23,r4 /* Is this our entry? */ + beq skpinv /* If so, skip the inval */ + tlbwe r3,r4,PPC44x_TLB_PAGEID /* If not, inval the entry */ +skpinv: addi r4,r4,1 /* Increment */ + cmpwi r4,64 /* Are we done? */ + bne 1b /* If not, repeat */ + isync /* If so, context change */ + +/* + * Configure and load pinned entry into TLB slot 63. + */ +#ifdef CONFIG_NONSTATIC_KERNEL + /* + * In case of a NONSTATIC_KERNEL we reuse the TLB XLAT + * entries of the initial mapping set by the boot loader. + * The XLAT entry is stored in r25 + */ + + /* Read the XLAT entry for our current mapping */ + tlbre r25,r23,PPC44x_TLB_XLAT + + lis r3,KERNELBASE@h + ori r3,r3,KERNELBASE@l + + /* Use our current RPN entry */ + mr r4,r25 +#else + + lis r3,PAGE_OFFSET@h + ori r3,r3,PAGE_OFFSET@l + + /* Kernel is at the base of RAM */ + li r4, 0 /* Load the kernel physical address */ +#endif + + /* Load the kernel PID = 0 */ + li r0,0 + mtspr SPRN_PID,r0 + sync + + /* Initialize MMUCR */ + li r5,0 + mtspr SPRN_MMUCR,r5 + sync + + /* pageid fields */ + clrrwi r3,r3,10 /* Mask off the effective page number */ + ori r3,r3,PPC44x_TLB_VALID | PPC44x_TLB_256M + + /* xlat fields */ + clrrwi r4,r4,10 /* Mask off the real page number */ + /* ERPN is 0 for first 4GB page */ + + /* attrib fields */ + /* Added guarded bit to protect against speculative loads/stores */ + li r5,0 + ori r5,r5,(PPC44x_TLB_SW | PPC44x_TLB_SR | PPC44x_TLB_SX | PPC44x_TLB_G) + + li r0,63 /* TLB slot 63 */ + + tlbwe r3,r0,PPC44x_TLB_PAGEID /* Load the pageid fields */ + tlbwe r4,r0,PPC44x_TLB_XLAT /* Load the translation fields */ + tlbwe r5,r0,PPC44x_TLB_ATTRIB /* Load the attrib/access fields */ + + /* Force context change */ + mfmsr r0 + mtspr SPRN_SRR1, r0 + lis r0,3f@h + ori r0,r0,3f@l + mtspr SPRN_SRR0,r0 + sync + rfi + + /* If necessary, invalidate original entry we used */ +3: cmpwi r23,63 + beq 4f + li r6,0 + tlbwe r6,r23,PPC44x_TLB_PAGEID + isync + +4: +#ifdef CONFIG_PPC_EARLY_DEBUG_44x + /* Add UART mapping for early debug. */ + + /* pageid fields */ + lis r3,PPC44x_EARLY_DEBUG_VIRTADDR@h + ori r3,r3,PPC44x_TLB_VALID|PPC44x_TLB_TS|PPC44x_TLB_64K + + /* xlat fields */ + lis r4,CONFIG_PPC_EARLY_DEBUG_44x_PHYSLOW@h + ori r4,r4,CONFIG_PPC_EARLY_DEBUG_44x_PHYSHIGH + + /* attrib fields */ + li r5,(PPC44x_TLB_SW|PPC44x_TLB_SR|PPC44x_TLB_I|PPC44x_TLB_G) + li r0,62 /* TLB slot 0 */ + + tlbwe r3,r0,PPC44x_TLB_PAGEID + tlbwe r4,r0,PPC44x_TLB_XLAT + tlbwe r5,r0,PPC44x_TLB_ATTRIB + + /* Force context change */ + isync +#endif /* CONFIG_PPC_EARLY_DEBUG_44x */ + + /* Establish the interrupt vector offsets */ + SET_IVOR(0, CriticalInput); + SET_IVOR(1, MachineCheck); + SET_IVOR(2, DataStorage); + SET_IVOR(3, InstructionStorage); + SET_IVOR(4, ExternalInput); + SET_IVOR(5, Alignment); + SET_IVOR(6, Program); + SET_IVOR(7, FloatingPointUnavailable); + SET_IVOR(8, SystemCall); + SET_IVOR(9, AuxillaryProcessorUnavailable); + SET_IVOR(10, Decrementer); + SET_IVOR(11, FixedIntervalTimer); + SET_IVOR(12, WatchdogTimer); + SET_IVOR(13, DataTLBError44x); + SET_IVOR(14, InstructionTLBError44x); + SET_IVOR(15, DebugCrit); + + b head_start_common + + +#ifdef CONFIG_PPC_47x + +#ifdef CONFIG_SMP + +/* Entry point for secondary 47x processors */ +_GLOBAL(start_secondary_47x) + mr r24,r3 /* CPU number */ + + bl init_cpu_state + + /* Now we need to bolt the rest of kernel memory which + * is done in C code. We must be careful because our task + * struct or our stack can (and will probably) be out + * of reach of the initial 256M TLB entry, so we use a + * small temporary stack in .bss for that. This works + * because only one CPU at a time can be in this code + */ + lis r1,temp_boot_stack@h + ori r1,r1,temp_boot_stack@l + addi r1,r1,1024-STACK_FRAME_OVERHEAD + li r0,0 + stw r0,0(r1) + bl mmu_init_secondary + + /* Now we can get our task struct and real stack pointer */ + + /* Get current's stack and current */ + lis r2,secondary_current@ha + lwz r2,secondary_current@l(r2) + lwz r1,TASK_STACK(r2) + + /* Current stack pointer */ + addi r1,r1,THREAD_SIZE-STACK_FRAME_OVERHEAD + li r0,0 + stw r0,0(r1) + + /* Kernel stack for exception entry in SPRG3 */ + addi r4,r2,THREAD /* init task's THREAD */ + mtspr SPRN_SPRG3,r4 + + b start_secondary + +#endif /* CONFIG_SMP */ + +/* + * Set up the initial MMU state for 44x + * + * We are still executing code at the virtual address + * mappings set by the firmware for the base of RAM. + */ + +head_start_47x: + /* Load our current PID->MMUCR TID and MSR IS->MMUCR STS */ + mfspr r3,SPRN_PID /* Get PID */ + mfmsr r4 /* Get MSR */ + andi. r4,r4,MSR_IS@l /* TS=1? */ + beq 1f /* If not, leave STS=0 */ + oris r3,r3,PPC47x_MMUCR_STS@h /* Set STS=1 */ +1: mtspr SPRN_MMUCR,r3 /* Put MMUCR */ + sync + + /* Find the entry we are running from */ + bl 1f +1: mflr r23 + tlbsx r23,0,r23 + tlbre r24,r23,0 + tlbre r25,r23,1 + tlbre r26,r23,2 + +/* + * Cleanup time + */ + + /* Initialize MMUCR */ + li r5,0 + mtspr SPRN_MMUCR,r5 + sync + +clear_all_utlb_entries: + + #; Set initial values. + + addis r3,0,0x8000 + addi r4,0,0 + addi r5,0,0 + b clear_utlb_entry + + #; Align the loop to speed things up. + + .align 6 + +clear_utlb_entry: + + tlbwe r4,r3,0 + tlbwe r5,r3,1 + tlbwe r5,r3,2 + addis r3,r3,0x2000 + cmpwi r3,0 + bne clear_utlb_entry + addis r3,0,0x8000 + addis r4,r4,0x100 + cmpwi r4,0 + bne clear_utlb_entry + + #; Restore original entry. + + oris r23,r23,0x8000 /* specify the way */ + tlbwe r24,r23,0 + tlbwe r25,r23,1 + tlbwe r26,r23,2 + +/* + * Configure and load pinned entry into TLB for the kernel core + */ + + lis r3,PAGE_OFFSET@h + ori r3,r3,PAGE_OFFSET@l + + /* Load the kernel PID = 0 */ + li r0,0 + mtspr SPRN_PID,r0 + sync + + /* Word 0 */ + clrrwi r3,r3,12 /* Mask off the effective page number */ + ori r3,r3,PPC47x_TLB0_VALID | PPC47x_TLB0_256M + + /* Word 1 - use r25. RPN is the same as the original entry */ + + /* Word 2 */ + li r5,0 + ori r5,r5,PPC47x_TLB2_S_RWX +#ifdef CONFIG_SMP + ori r5,r5,PPC47x_TLB2_M +#endif + + /* We write to way 0 and bolted 0 */ + lis r0,0x8800 + tlbwe r3,r0,0 + tlbwe r25,r0,1 + tlbwe r5,r0,2 + +/* + * Configure SSPCR, ISPCR and USPCR for now to search everything, we can fix + * them up later + */ + LOAD_REG_IMMEDIATE(r3, 0x9abcdef0) + mtspr SPRN_SSPCR,r3 + mtspr SPRN_USPCR,r3 + LOAD_REG_IMMEDIATE(r3, 0x12345670) + mtspr SPRN_ISPCR,r3 + + /* Force context change */ + mfmsr r0 + mtspr SPRN_SRR1, r0 + lis r0,3f@h + ori r0,r0,3f@l + mtspr SPRN_SRR0,r0 + sync + rfi + + /* Invalidate original entry we used */ +3: + rlwinm r24,r24,0,21,19 /* clear the "valid" bit */ + tlbwe r24,r23,0 + addi r24,0,0 + tlbwe r24,r23,1 + tlbwe r24,r23,2 + isync /* Clear out the shadow TLB entries */ + +#ifdef CONFIG_PPC_EARLY_DEBUG_44x + /* Add UART mapping for early debug. */ + + /* Word 0 */ + lis r3,PPC44x_EARLY_DEBUG_VIRTADDR@h + ori r3,r3,PPC47x_TLB0_VALID | PPC47x_TLB0_TS | PPC47x_TLB0_1M + + /* Word 1 */ + lis r4,CONFIG_PPC_EARLY_DEBUG_44x_PHYSLOW@h + ori r4,r4,CONFIG_PPC_EARLY_DEBUG_44x_PHYSHIGH + + /* Word 2 */ + li r5,(PPC47x_TLB2_S_RW | PPC47x_TLB2_IMG) + + /* Bolted in way 0, bolt slot 5, we -hope- we don't hit the same + * congruence class as the kernel, we need to make sure of it at + * some point + */ + lis r0,0x8d00 + tlbwe r3,r0,0 + tlbwe r4,r0,1 + tlbwe r5,r0,2 + + /* Force context change */ + isync +#endif /* CONFIG_PPC_EARLY_DEBUG_44x */ + + /* Establish the interrupt vector offsets */ + SET_IVOR(0, CriticalInput); + SET_IVOR(1, MachineCheckA); + SET_IVOR(2, DataStorage); + SET_IVOR(3, InstructionStorage); + SET_IVOR(4, ExternalInput); + SET_IVOR(5, Alignment); + SET_IVOR(6, Program); + SET_IVOR(7, FloatingPointUnavailable); + SET_IVOR(8, SystemCall); + SET_IVOR(9, AuxillaryProcessorUnavailable); + SET_IVOR(10, Decrementer); + SET_IVOR(11, FixedIntervalTimer); + SET_IVOR(12, WatchdogTimer); + SET_IVOR(13, DataTLBError47x); + SET_IVOR(14, InstructionTLBError47x); + SET_IVOR(15, DebugCrit); + + /* We configure icbi to invalidate 128 bytes at a time since the + * current 32-bit kernel code isn't too happy with icache != dcache + * block size. We also disable the BTAC as this can cause errors + * in some circumstances (see IBM Erratum 47). + */ + mfspr r3,SPRN_CCR0 + oris r3,r3,0x0020 + ori r3,r3,0x0040 + mtspr SPRN_CCR0,r3 + isync + +#endif /* CONFIG_PPC_47x */ + +/* + * Here we are back to code that is common between 44x and 47x + * + * We proceed to further kernel initialization and return to the + * main kernel entry + */ +head_start_common: + /* Establish the interrupt vector base */ + lis r4,interrupt_base@h /* IVPR only uses the high 16-bits */ + mtspr SPRN_IVPR,r4 + + /* + * If the kernel was loaded at a non-zero 256 MB page, we need to + * mask off the most significant 4 bits to get the relative address + * from the start of physical memory + */ + rlwinm r22,r22,0,4,31 + addis r22,r22,PAGE_OFFSET@h + mtlr r22 + isync + blr + +/* + * 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 + .align PAGE_SHIFT + .globl sdata +sdata: + .globl empty_zero_page +empty_zero_page: + .space PAGE_SIZE +EXPORT_SYMBOL(empty_zero_page) + +/* + * To support >32-bit physical addresses, we use an 8KB pgdir. + */ + .globl swapper_pg_dir +swapper_pg_dir: + .space PGD_TABLE_SIZE + +/* + * Room for two PTE pointers, usually the kernel and current user pointers + * to their respective root page table. + */ +abatron_pteptrs: + .space 8 + +#ifdef CONFIG_SMP + .align 12 +temp_boot_stack: + .space 1024 +#endif /* CONFIG_SMP */ |