/* * 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 * 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 #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* 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 /* stash r4 for book3e */ mr r25,r4 /* 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 li r26,0 #ifdef CONFIG_PPC_BOOK3E tovirt(r26,r26) #endif /* All secondary cpus wait here until told to start. */ 100: ld r4,__secondary_hold_spinloop-_stext(r26) cmpdi 0,r4,0 beq 100b #if defined(CONFIG_SMP) || defined(CONFIG_KEXEC) #ifdef CONFIG_PPC_BOOK3E tovirt(r4,r4) #endif ld r4,0(r4) /* deref function descriptor */ mtctr r4 mr r3,r24 /* * it may be the case that other platforms have r4 right to * begin with, this gives us some safety in case it is not */ #ifdef CONFIG_PPC_BOOK3E mr r4,r25 #else li r4,0 #endif /* 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 tovirt(r2,r2) #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 tovirt(r2,r2) #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_RELOCATABLE /* * 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 /* just copy interrupts */ LOAD_REG_IMMEDIATE(r5, __end_interrupts - _stext) 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 .balign 8 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 isync 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 tovirt(r2,r2) /* 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. * * Note: The compiler constructs pointers using offsets from the * TOC in -mcmodel=medium mode. After we relocate to 0 but before * the MMU is on we need our TOC to be a virtual address otherwise * these pointers will be real addresses which may get stored and * accessed later with the MMU on. We use tovirt() at the call * sites to handle this. */ _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 .balign 8 p_toc: .llong __toc_start + 0x8000 - 0b /* * This is where the main kernel code starts. */ _INIT_STATIC(start_here_multiplatform) /* set up the TOC */ bl .relative_toc tovirt(r2,r2) /* 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