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Diffstat (limited to 'arch/powerpc/kernel/head_64.S')
| -rw-r--r-- | arch/powerpc/kernel/head_64.S | 1007 |
1 files changed, 1007 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/head_64.S b/arch/powerpc/kernel/head_64.S new file mode 100644 index 000000000..dedcc6fe2 --- /dev/null +++ b/arch/powerpc/kernel/head_64.S @@ -0,0 +1,1007 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * 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. + */ + +#include <linux/threads.h> +#include <linux/init.h> +#include <asm/reg.h> +#include <asm/page.h> +#include <asm/mmu.h> +#include <asm/ppc_asm.h> +#include <asm/head-64.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> +#include <asm/cputhreads.h> +#include <asm/ppc-opcode.h> +#include <asm/export.h> +#include <asm/feature-fixups.h> +#ifdef CONFIG_PPC_BOOK3S +#include <asm/exception-64s.h> +#else +#include <asm/exception-64e.h> +#endif + +/* 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 primary CPU enters at __start. + * 3. If the RTAS supports "query-cpu-stopped-state", then secondary + * CPUs will enter as directed by "start-cpu" RTAS call, which is + * generic_secondary_smp_init, with PIR in r3. + * 4. Else the secondary CPUs will enter at secondary_hold (0x60) as + * directed by the "start-cpu" RTS call, with PIR in r3. + * -or- For OPAL entry: + * 1. The MMU is off, processor in HV mode. + * 2. The primary CPU enters at 0 with device-tree in r3, OPAL base + * in r8, and entry in r9 for debugging purposes. + * 3. Secondary CPUs enter as directed by OPAL_START_CPU call, which + * is at generic_secondary_smp_init, with PIR in r3. + * + * For Book3E processors: + * 1. The MMU is on running in AS0 in a state defined in ePAPR + * 2. The kernel is entered at __start + */ + +OPEN_FIXED_SECTION(first_256B, 0x0, 0x100) +USE_FIXED_SECTION(first_256B) + /* + * Offsets are relative from the start of fixed section, and + * first_256B starts at 0. Offsets are a bit easier to use here + * than the fixed section entry macros. + */ + . = 0x0 +_GLOBAL(__start) + /* NOP this out unconditionally */ +BEGIN_FTR_SECTION + FIXUP_ENDIAN + 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 non-zero. + * When non-zero, it contains the real address of the function the cpu + * should jump to. + */ + .balign 8 + .globl __secondary_hold_spinloop +__secondary_hold_spinloop: + .8byte 0x0 + + /* Secondary processors write this value with their cpu # */ + /* after they enter the spin loop immediately below. */ + .globl __secondary_hold_acknowledge +__secondary_hold_acknowledge: + .8byte 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 kdump kernel in the + * crash_kernel region. The loader is responsible for + * observing the alignment requirement. + */ + +#ifdef CONFIG_RELOCATABLE_TEST +#define RUN_AT_LOAD_DEFAULT 1 /* Test relocation, do not copy to 0 */ +#else +#define RUN_AT_LOAD_DEFAULT 0x72756e30 /* "run0" -- relocate to 0 by default */ +#endif + + /* Do not move this variable as kexec-tools knows about it. */ + . = 0x5c + .globl __run_at_load +__run_at_load: +DEFINE_FIXED_SYMBOL(__run_at_load, first_256B) + .long RUN_AT_LOAD_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: + FIXUP_ENDIAN +#ifndef CONFIG_PPC_BOOK3E_64 + 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,(ABS_ADDR(__secondary_hold_acknowledge, first_256B))(0) + sync + + li r26,0 +#ifdef CONFIG_PPC_BOOK3E_64 + tovirt(r26,r26) +#endif + /* All secondary cpus wait here until told to start. */ +100: ld r12,(ABS_ADDR(__secondary_hold_spinloop, first_256B))(r26) + cmpdi 0,r12,0 + beq 100b + +#if defined(CONFIG_SMP) || defined(CONFIG_KEXEC_CORE) +#ifdef CONFIG_PPC_BOOK3E_64 + tovirt(r12,r12) +#endif + mtctr r12 + 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_64 + mr r4,r25 +#else + li r4,0 +#endif + /* Make sure that patched code is visible */ + isync + bctr +#else +0: trap + EMIT_BUG_ENTRY 0b, __FILE__, __LINE__, 0 +#endif +CLOSE_FIXED_SECTION(first_256B) + +/* + * 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" +#else +OPEN_TEXT_SECTION(0x100) +#endif + +USE_TEXT_SECTION() + +#include "interrupt_64.S" + +#ifdef CONFIG_PPC_BOOK3E_64 +/* + * The booting_thread_hwid holds the thread id we want to boot in cpu + * hotplug case. It is set by cpu hotplug code, and is invalid by default. + * The thread id is the same as the initial value of SPRN_PIR[THREAD_ID] + * bit field. + */ + .globl booting_thread_hwid +booting_thread_hwid: + .long INVALID_THREAD_HWID + .align 3 +/* + * start a thread in the same core + * input parameters: + * r3 = the thread physical id + * r4 = the entry point where thread starts + */ +_GLOBAL(book3e_start_thread) + LOAD_REG_IMMEDIATE(r5, MSR_KERNEL) + cmpwi r3, 0 + beq 10f + cmpwi r3, 1 + beq 11f + /* If the thread id is invalid, just exit. */ + b 13f +10: + MTTMR(TMRN_IMSR0, 5) + MTTMR(TMRN_INIA0, 4) + b 12f +11: + MTTMR(TMRN_IMSR1, 5) + MTTMR(TMRN_INIA1, 4) +12: + isync + li r6, 1 + sld r6, r6, r3 + mtspr SPRN_TENS, r6 +13: + blr + +/* + * stop a thread in the same core + * input parameter: + * r3 = the thread physical id + */ +_GLOBAL(book3e_stop_thread) + cmpwi r3, 0 + beq 10f + cmpwi r3, 1 + beq 10f + /* If the thread id is invalid, just exit. */ + b 13f +10: + li r4, 1 + sld r4, r4, r3 + mtspr SPRN_TENC, r4 +13: + blr + +_GLOBAL(fsl_secondary_thread_init) + mfspr r4,SPRN_BUCSR + + /* Enable branch prediction */ + lis r3,BUCSR_INIT@h + ori r3,r3,BUCSR_INIT@l + mtspr SPRN_BUCSR,r3 + isync + + /* + * Fix PIR to match the linear numbering in the device tree. + * + * On e6500, the reset value of PIR uses the low three bits for + * the thread within a core, and the upper bits for the core + * number. There are two threads per core, so shift everything + * but the low bit right by two bits so that the cpu numbering is + * continuous. + * + * If the old value of BUCSR is non-zero, this thread has run + * before. Thus, we assume we are coming from kexec or a similar + * scenario, and PIR is already set to the correct value. This + * is a bit of a hack, but there are limited opportunities for + * getting information into the thread and the alternatives + * seemed like they'd be overkill. We can't tell just by looking + * at the old PIR value which state it's in, since the same value + * could be valid for one thread out of reset and for a different + * thread in Linux. + */ + + mfspr r3, SPRN_PIR + cmpwi r4,0 + bne 1f + rlwimi r3, r3, 30, 2, 30 + mtspr SPRN_PIR, r3 +1: + 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) + + /* Book3E initialization */ + mr r3,r24 + bl book3e_secondary_thread_init + b generic_secondary_common_init + +#endif /* CONFIG_PPC_BOOK3E_64 */ + +/* + * 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) + FIXUP_ENDIAN + 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_64 + /* Book3E initialization */ + mr r3,r24 + mr r4,r25 + bl book3e_secondary_core_init + +/* + * After common core init has finished, check if the current thread is the + * one we wanted to boot. If not, start the specified thread and stop the + * current thread. + */ + LOAD_REG_ADDR(r4, booting_thread_hwid) + lwz r3, 0(r4) + li r5, INVALID_THREAD_HWID + cmpw r3, r5 + beq 20f + + /* + * The value of booting_thread_hwid has been stored in r3, + * so make it invalid. + */ + stw r5, 0(r4) + + /* + * Get the current thread id and check if it is the one we wanted. + * If not, start the one specified in booting_thread_hwid and stop + * the current thread. + */ + mfspr r8, SPRN_TIR + cmpw r3, r8 + beq 20f + + /* start the specified thread */ + LOAD_REG_ADDR(r5, fsl_secondary_thread_init) + ld r4, 0(r5) + bl book3e_start_thread + + /* stop the current thread */ + mr r3, r8 + bl book3e_stop_thread +10: + b 10b +20: +#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. + */ +#ifndef CONFIG_SMP + b kexec_wait /* wait for next kernel if !SMP */ +#else + LOAD_REG_ADDR(r8, paca_ptrs) /* Load paca_ptrs pointe */ + ld r8,0(r8) /* Get base vaddr of array */ +#if (NR_CPUS == 1) || defined(CONFIG_FORCE_NR_CPUS) + LOAD_REG_IMMEDIATE(r7, NR_CPUS) +#else + LOAD_REG_ADDR(r7, nr_cpu_ids) /* Load nr_cpu_ids address */ + lwz r7,0(r7) /* also the max paca allocated */ +#endif + li r5,0 /* logical cpu id */ +1: + sldi r9,r5,3 /* get paca_ptrs[] index from cpu id */ + ldx r13,r9,r8 /* r13 = paca_ptrs[cpu id] */ + lhz r6,PACAHWCPUID(r13) /* Load HW procid from paca */ + cmpw r6,r24 /* Compare to our id */ + beq 2f + 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_64 + 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 + + /* Create a temp kernel stack for use before relocation is on. */ + ld r1,PACAEMERGSP(r13) + subi r1,r1,STACK_FRAME_OVERHEAD + + /* See if we need to call a cpu state restore handler */ + LOAD_REG_ADDR(r23, cur_cpu_spec) + ld r23,0(r23) + ld r12,CPU_SPEC_RESTORE(r23) + cmpdi 0,r12,0 + beq 3f +#ifdef CONFIG_PPC64_ELF_ABI_V1 + ld r12,0(r12) +#endif + mtctr r12 + 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 */ + + b __secondary_start +#endif /* SMP */ + +/* + * Turn the MMU off. + * Assumes we're mapped EA == RA if the MMU is on. + */ +#ifdef CONFIG_PPC_BOOK3S +__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 + * + */ +__start_initialization_multiplatform: + /* Make sure we are running in 64 bits mode */ + bl enable_64b_mode + + /* Zero r13 (paca) so early program check / mce don't use it */ + li r13,0 + + /* 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_64 + 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_64 */ + +__REF +__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 + .previous + +__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 +#if defined(CONFIG_PPC_BOOK3E_64) + tovirt(r26,r26) /* on booke, we already run at PAGE_OFFSET */ +#endif + lwz r7,(FIXED_SYMBOL_ABS_ADDR(__run_at_load))(r26) +#if defined(CONFIG_PPC_BOOK3E_64) + tophys(r26,r26) +#endif + cmplwi cr0,r7,1 /* flagged to stay where we are ? */ + bne 1f + add r25,r25,r26 +1: mr r3,r25 + bl relocate +#if defined(CONFIG_PPC_BOOK3E_64) + /* IVPR needs to be set after relocation. */ + bl init_core_book3e +#endif +#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_64 + tovirt(r3,r3) /* on booke, we already run at PAGE_OFFSET */ +#endif + mr. r4,r26 /* In some cases the loader may */ +#if defined(CONFIG_PPC_BOOK3E_64) + tovirt(r4,r4) +#endif + beq 9f /* have already put us at zero */ + li r6,0x100 /* Start offset, the first 0x100 */ + /* bytes were copied earlier. */ + +#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 + */ +#if defined(CONFIG_PPC_BOOK3E_64) + tovirt(r26,r26) /* on booke, we already run at PAGE_OFFSET */ +#endif + lwz r7,(FIXED_SYMBOL_ABS_ADDR(__run_at_load))(r26) + cmplwi cr0,r7,1 + bne 3f + +#ifdef CONFIG_PPC_BOOK3E_64 + LOAD_REG_ADDR(r5, __end_interrupts) + LOAD_REG_ADDR(r11, _stext) + sub r5,r5,r11 +#else + /* just copy interrupts */ + LOAD_REG_IMMEDIATE_SYM(r5, r11, FIXED_SYMBOL_ABS_ADDR(__end_interrupts)) +#endif + b 5f +3: +#endif + /* # bytes of memory to copy */ + lis r5,(ABS_ADDR(copy_to_here, text))@ha + addi r5,r5,(ABS_ADDR(copy_to_here, text))@l + + bl copy_and_flush /* copy the first n bytes */ + /* this includes the code being */ + /* executed here. */ + /* Jump to the copy of this code that we just made */ + addis r8,r3,(ABS_ADDR(4f, text))@ha + addi r12,r8,(ABS_ADDR(4f, text))@l + mtctr r12 + bctr + +.balign 8 +p_end: .8byte _end - copy_to_here + +4: + /* + * Now copy the rest of the kernel up to _end, add + * _end - copy_to_here to the copy limit and run again. + */ + addis r8,r26,(ABS_ADDR(p_end, text))@ha + ld r8,(ABS_ADDR(p_end, text))@l(r8) + add r5,r5,r8 +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 + +_ASM_NOKPROBE_SYMBOL(copy_and_flush); /* Called in real mode */ + +.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_ptrs) /* Load paca pointer */ + ld r4,0(r4) /* Get base vaddr of paca_ptrs array */ + sldi r5,r24,3 /* get paca_ptrs[] index from cpu id */ + ldx r13,r5,r4 /* r13 = paca_ptrs[cpu id] */ + 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,IRQS_DISABLED + stb r0,PACAIRQSOFTMASK(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 + + /* + * Do early setup for this CPU, in particular initialising the MMU so we + * can turn it on below. This is a call to C, which is OK, we're still + * running on the emergency stack. + */ + bl early_setup_secondary + + /* + * The primary has initialized our kernel stack for us in the paca, grab + * it and put it in r1. We must *not* use it until we turn on the MMU + * below, because it may not be inside the RMO. + */ + ld r1, PACAKSAVE(r13) + + /* 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) + */ + li r7,IRQS_DISABLED + stb r7,PACAIRQSOFTMASK(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_TO_KERNEL + 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. + */ +start_secondary_prolog: + LOAD_PACA_TOC() + 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 + */ +enable_64b_mode: + mfmsr r11 /* grab the current MSR */ +#ifdef CONFIG_PPC_BOOK3E_64 + oris r11,r11,0x8000 /* CM bit set, we'll set ICM later */ + mtmsr r11 +#else /* CONFIG_PPC_BOOK3E_64 */ + LOAD_REG_IMMEDIATE(r12, MSR_64BIT) + 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: .8byte .TOC. - 0b + +/* + * This is where the main kernel code starts. + */ +__REF +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_64 + 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 + + /* set up a stack pointer */ + LOAD_REG_ADDR(r3,init_thread_union) + LOAD_REG_IMMEDIATE(r1,THREAD_SIZE) + add r1,r3,r1 + li r0,0 + stdu r0,-STACK_FRAME_OVERHEAD(r1) + + /* + * Do very early kernel initializations, including initial hash table + * and SLB setup before we turn on relocation. + */ + +#ifdef CONFIG_KASAN + bl kasan_early_init +#endif + /* Restore parameters passed from prom_init/kexec */ + mr r3,r31 + LOAD_REG_ADDR(r12, DOTSYM(early_setup)) + mtctr r12 + bctrl /* 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_TO_KERNEL + b . /* prevent speculative execution */ + + /* This is where all platforms converge execution */ + +start_here_common: + /* relocation is on at this point */ + std r1,PACAKSAVE(r13) + + /* Load the TOC (virtual address) */ + LOAD_PACA_TOC() + + /* Mark interrupts soft and hard disabled (they might be enabled + * in the PACA when doing hotplug) + */ + li r0,IRQS_DISABLED + stb r0,PACAIRQSOFTMASK(r13) + li r0,PACA_IRQ_HARD_DIS + stb r0,PACAIRQHAPPENED(r13) + + /* Generic kernel entry */ + bl start_kernel + + /* Not reached */ +0: trap + EMIT_BUG_ENTRY 0b, __FILE__, __LINE__, 0 + .previous |