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linux/arch/powerpc/kernel/misc_64.S
Michael Ellerman 2621e945fb powerpc/kexec: Fix kexec/kdump in P9 guest kernels 
The code that cleans up the IAMR/AMOR before kexec'ing failed to
remember that when we're running as a guest AMOR is not writable, it's
hypervisor privileged.

They symptom is that the kexec stops before entering purgatory and
nothing else is seen on the console. If you examine the state of the
system all threads will be in the 0x700 program check handler.

Fix it by making the write to AMOR dependent on HV mode.

Fixes: 1e2a516e89 ("powerpc/kexec: Fix radix to hash kexec due to IAMR/AMOR")
Cc: stable@vger.kernel.org # v4.10+
Reported-by: Yilin Zhang <yilzhang@redhat.com>
Debugged-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Acked-by: Balbir Singh <bsingharora@gmail.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Tested-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-11-24 16:49:37 +11:00

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/*
* This file contains miscellaneous low-level functions.
* Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
*
* Largely rewritten by Cort Dougan (cort@cs.nmt.edu)
* and Paul Mackerras.
* Adapted for iSeries by Mike Corrigan (mikejc@us.ibm.com)
* PPC64 updates by Dave Engebretsen (engebret@us.ibm.com)
*
* 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/sys.h>
#include <asm/unistd.h>
#include <asm/errno.h>
#include <asm/processor.h>
#include <asm/page.h>
#include <asm/cache.h>
#include <asm/ppc_asm.h>
#include <asm/asm-offsets.h>
#include <asm/cputable.h>
#include <asm/thread_info.h>
#include <asm/kexec.h>
#include <asm/ptrace.h>
#include <asm/mmu.h>
#include <asm/export.h>
.text
_GLOBAL(call_do_softirq)
mflr r0
std r0,16(r1)
stdu r1,THREAD_SIZE-STACK_FRAME_OVERHEAD(r3)
mr r1,r3
bl __do_softirq
ld r1,0(r1)
ld r0,16(r1)
mtlr r0
blr
_GLOBAL(call_do_irq)
mflr r0
std r0,16(r1)
stdu r1,THREAD_SIZE-STACK_FRAME_OVERHEAD(r4)
mr r1,r4
bl __do_irq
ld r1,0(r1)
ld r0,16(r1)
mtlr r0
blr
.section ".toc","aw"
PPC64_CACHES:
.tc ppc64_caches[TC],ppc64_caches
.section ".text"
/*
* Write any modified data cache blocks out to memory
* and invalidate the corresponding instruction cache blocks.
*
* flush_icache_range(unsigned long start, unsigned long stop)
*
* flush all bytes from start through stop-1 inclusive
*/
_GLOBAL_TOC(flush_icache_range)
BEGIN_FTR_SECTION
PURGE_PREFETCHED_INS
blr
END_FTR_SECTION_IFSET(CPU_FTR_COHERENT_ICACHE)
/*
* Flush the data cache to memory
*
* Different systems have different cache line sizes
* and in some cases i-cache and d-cache line sizes differ from
* each other.
*/
ld r10,PPC64_CACHES@toc(r2)
lwz r7,DCACHEL1BLOCKSIZE(r10)/* Get cache block size */
addi r5,r7,-1
andc r6,r3,r5 /* round low to line bdy */
subf r8,r6,r4 /* compute length */
add r8,r8,r5 /* ensure we get enough */
lwz r9,DCACHEL1LOGBLOCKSIZE(r10) /* Get log-2 of cache block size */
srw. r8,r8,r9 /* compute line count */
beqlr /* nothing to do? */
mtctr r8
1: dcbst 0,r6
add r6,r6,r7
bdnz 1b
sync
/* Now invalidate the instruction cache */
lwz r7,ICACHEL1BLOCKSIZE(r10) /* Get Icache block size */
addi r5,r7,-1
andc r6,r3,r5 /* round low to line bdy */
subf r8,r6,r4 /* compute length */
add r8,r8,r5
lwz r9,ICACHEL1LOGBLOCKSIZE(r10) /* Get log-2 of Icache block size */
srw. r8,r8,r9 /* compute line count */
beqlr /* nothing to do? */
mtctr r8
2: icbi 0,r6
add r6,r6,r7
bdnz 2b
isync
blr
_ASM_NOKPROBE_SYMBOL(flush_icache_range)
EXPORT_SYMBOL(flush_icache_range)
/*
* Like above, but only do the D-cache.
*
* flush_dcache_range(unsigned long start, unsigned long stop)
*
* flush all bytes from start to stop-1 inclusive
*/
_GLOBAL_TOC(flush_dcache_range)
/*
* Flush the data cache to memory
*
* Different systems have different cache line sizes
*/
ld r10,PPC64_CACHES@toc(r2)
lwz r7,DCACHEL1BLOCKSIZE(r10) /* Get dcache block size */
addi r5,r7,-1
andc r6,r3,r5 /* round low to line bdy */
subf r8,r6,r4 /* compute length */
add r8,r8,r5 /* ensure we get enough */
lwz r9,DCACHEL1LOGBLOCKSIZE(r10) /* Get log-2 of dcache block size */
srw. r8,r8,r9 /* compute line count */
beqlr /* nothing to do? */
mtctr r8
0: dcbst 0,r6
add r6,r6,r7
bdnz 0b
sync
blr
EXPORT_SYMBOL(flush_dcache_range)
/*
* Like above, but works on non-mapped physical addresses.
* Use only for non-LPAR setups ! It also assumes real mode
* is cacheable. Used for flushing out the DART before using
* it as uncacheable memory
*
* flush_dcache_phys_range(unsigned long start, unsigned long stop)
*
* flush all bytes from start to stop-1 inclusive
*/
_GLOBAL(flush_dcache_phys_range)
ld r10,PPC64_CACHES@toc(r2)
lwz r7,DCACHEL1BLOCKSIZE(r10) /* Get dcache block size */
addi r5,r7,-1
andc r6,r3,r5 /* round low to line bdy */
subf r8,r6,r4 /* compute length */
add r8,r8,r5 /* ensure we get enough */
lwz r9,DCACHEL1LOGBLOCKSIZE(r10) /* Get log-2 of dcache block size */
srw. r8,r8,r9 /* compute line count */
beqlr /* nothing to do? */
mfmsr r5 /* Disable MMU Data Relocation */
ori r0,r5,MSR_DR
xori r0,r0,MSR_DR
sync
mtmsr r0
sync
isync
mtctr r8
0: dcbst 0,r6
add r6,r6,r7
bdnz 0b
sync
isync
mtmsr r5 /* Re-enable MMU Data Relocation */
sync
isync
blr
_GLOBAL(flush_inval_dcache_range)
ld r10,PPC64_CACHES@toc(r2)
lwz r7,DCACHEL1BLOCKSIZE(r10) /* Get dcache block size */
addi r5,r7,-1
andc r6,r3,r5 /* round low to line bdy */
subf r8,r6,r4 /* compute length */
add r8,r8,r5 /* ensure we get enough */
lwz r9,DCACHEL1LOGBLOCKSIZE(r10)/* Get log-2 of dcache block size */
srw. r8,r8,r9 /* compute line count */
beqlr /* nothing to do? */
sync
isync
mtctr r8
0: dcbf 0,r6
add r6,r6,r7
bdnz 0b
sync
isync
blr
/*
* Flush a particular page from the data cache to RAM.
* Note: this is necessary because the instruction cache does *not*
* snoop from the data cache.
*
* void __flush_dcache_icache(void *page)
*/
_GLOBAL(__flush_dcache_icache)
/*
* Flush the data cache to memory
*
* Different systems have different cache line sizes
*/
BEGIN_FTR_SECTION
PURGE_PREFETCHED_INS
blr
END_FTR_SECTION_IFSET(CPU_FTR_COHERENT_ICACHE)
/* Flush the dcache */
ld r7,PPC64_CACHES@toc(r2)
clrrdi r3,r3,PAGE_SHIFT /* Page align */
lwz r4,DCACHEL1BLOCKSPERPAGE(r7) /* Get # dcache blocks per page */
lwz r5,DCACHEL1BLOCKSIZE(r7) /* Get dcache block size */
mr r6,r3
mtctr r4
0: dcbst 0,r6
add r6,r6,r5
bdnz 0b
sync
/* Now invalidate the icache */
lwz r4,ICACHEL1BLOCKSPERPAGE(r7) /* Get # icache blocks per page */
lwz r5,ICACHEL1BLOCKSIZE(r7) /* Get icache block size */
mtctr r4
1: icbi 0,r3
add r3,r3,r5
bdnz 1b
isync
blr
_GLOBAL(__bswapdi2)
EXPORT_SYMBOL(__bswapdi2)
srdi r8,r3,32
rlwinm r7,r3,8,0xffffffff
rlwimi r7,r3,24,0,7
rlwinm r9,r8,8,0xffffffff
rlwimi r7,r3,24,16,23
rlwimi r9,r8,24,0,7
rlwimi r9,r8,24,16,23
sldi r7,r7,32
or r3,r7,r9
blr
#ifdef CONFIG_PPC_EARLY_DEBUG_BOOTX
_GLOBAL(rmci_on)
sync
isync
li r3,0x100
rldicl r3,r3,32,0
mfspr r5,SPRN_HID4
or r5,r5,r3
sync
mtspr SPRN_HID4,r5
isync
slbia
isync
sync
blr
_GLOBAL(rmci_off)
sync
isync
li r3,0x100
rldicl r3,r3,32,0
mfspr r5,SPRN_HID4
andc r5,r5,r3
sync
mtspr SPRN_HID4,r5
isync
slbia
isync
sync
blr
#endif /* CONFIG_PPC_EARLY_DEBUG_BOOTX */
#if defined(CONFIG_PPC_PMAC) || defined(CONFIG_PPC_MAPLE)
/*
* Do an IO access in real mode
*/
_GLOBAL(real_readb)
mfmsr r7
ori r0,r7,MSR_DR
xori r0,r0,MSR_DR
sync
mtmsrd r0
sync
isync
mfspr r6,SPRN_HID4
rldicl r5,r6,32,0
ori r5,r5,0x100
rldicl r5,r5,32,0
sync
mtspr SPRN_HID4,r5
isync
slbia
isync
lbz r3,0(r3)
sync
mtspr SPRN_HID4,r6
isync
slbia
isync
mtmsrd r7
sync
isync
blr
/*
* Do an IO access in real mode
*/
_GLOBAL(real_writeb)
mfmsr r7
ori r0,r7,MSR_DR
xori r0,r0,MSR_DR
sync
mtmsrd r0
sync
isync
mfspr r6,SPRN_HID4
rldicl r5,r6,32,0
ori r5,r5,0x100
rldicl r5,r5,32,0
sync
mtspr SPRN_HID4,r5
isync
slbia
isync
stb r3,0(r4)
sync
mtspr SPRN_HID4,r6
isync
slbia
isync
mtmsrd r7
sync
isync
blr
#endif /* defined(CONFIG_PPC_PMAC) || defined(CONFIG_PPC_MAPLE) */
#ifdef CONFIG_PPC_PASEMI
_GLOBAL(real_205_readb)
mfmsr r7
ori r0,r7,MSR_DR
xori r0,r0,MSR_DR
sync
mtmsrd r0
sync
isync
LBZCIX(R3,R0,R3)
isync
mtmsrd r7
sync
isync
blr
_GLOBAL(real_205_writeb)
mfmsr r7
ori r0,r7,MSR_DR
xori r0,r0,MSR_DR
sync
mtmsrd r0
sync
isync
STBCIX(R3,R0,R4)
isync
mtmsrd r7
sync
isync
blr
#endif /* CONFIG_PPC_PASEMI */
#if defined(CONFIG_CPU_FREQ_PMAC64) || defined(CONFIG_CPU_FREQ_MAPLE)
/*
* SCOM access functions for 970 (FX only for now)
*
* unsigned long scom970_read(unsigned int address);
* void scom970_write(unsigned int address, unsigned long value);
*
* The address passed in is the 24 bits register address. This code
* is 970 specific and will not check the status bits, so you should
* know what you are doing.
*/
_GLOBAL(scom970_read)
/* interrupts off */
mfmsr r4
ori r0,r4,MSR_EE
xori r0,r0,MSR_EE
mtmsrd r0,1
/* rotate 24 bits SCOM address 8 bits left and mask out it's low 8 bits
* (including parity). On current CPUs they must be 0'd,
* and finally or in RW bit
*/
rlwinm r3,r3,8,0,15
ori r3,r3,0x8000
/* do the actual scom read */
sync
mtspr SPRN_SCOMC,r3
isync
mfspr r3,SPRN_SCOMD
isync
mfspr r0,SPRN_SCOMC
isync
/* XXX: fixup result on some buggy 970's (ouch ! we lost a bit, bah
* that's the best we can do). Not implemented yet as we don't use
* the scom on any of the bogus CPUs yet, but may have to be done
* ultimately
*/
/* restore interrupts */
mtmsrd r4,1
blr
_GLOBAL(scom970_write)
/* interrupts off */
mfmsr r5
ori r0,r5,MSR_EE
xori r0,r0,MSR_EE
mtmsrd r0,1
/* rotate 24 bits SCOM address 8 bits left and mask out it's low 8 bits
* (including parity). On current CPUs they must be 0'd.
*/
rlwinm r3,r3,8,0,15
sync
mtspr SPRN_SCOMD,r4 /* write data */
isync
mtspr SPRN_SCOMC,r3 /* write command */
isync
mfspr 3,SPRN_SCOMC
isync
/* restore interrupts */
mtmsrd r5,1
blr
#endif /* CONFIG_CPU_FREQ_PMAC64 || CONFIG_CPU_FREQ_MAPLE */
/* kexec_wait(phys_cpu)
*
* wait for the flag to change, indicating this kernel is going away but
* the slave code for the next one is at addresses 0 to 100.
*
* This is used by all slaves, even those that did not find a matching
* paca in the secondary startup code.
*
* Physical (hardware) cpu id should be in r3.
*/
_GLOBAL(kexec_wait)
bl 1f
1: mflr r5
addi r5,r5,kexec_flag-1b
99: HMT_LOW
#ifdef CONFIG_KEXEC_CORE /* use no memory without kexec */
lwz r4,0(r5)
cmpwi 0,r4,0
beq 99b
#ifdef CONFIG_PPC_BOOK3S_64
li r10,0x60
mfmsr r11
clrrdi r11,r11,1 /* Clear MSR_LE */
mtsrr0 r10
mtsrr1 r11
rfid
#else
/* Create TLB entry in book3e_secondary_core_init */
li r4,0
ba 0x60
#endif
#endif
/* this can be in text because we won't change it until we are
* running in real anyways
*/
kexec_flag:
.long 0
#ifdef CONFIG_KEXEC_CORE
#ifdef CONFIG_PPC_BOOK3E
/*
* BOOK3E has no real MMU mode, so we have to setup the initial TLB
* for a core to identity map v:0 to p:0. This current implementation
* assumes that 1G is enough for kexec.
*/
kexec_create_tlb:
/*
* Invalidate all non-IPROT TLB entries to avoid any TLB conflict.
* IPROT TLB entries should be >= PAGE_OFFSET and thus not conflict.
*/
PPC_TLBILX_ALL(0,R0)
sync
isync
mfspr r10,SPRN_TLB1CFG
andi. r10,r10,TLBnCFG_N_ENTRY /* Extract # entries */
subi r10,r10,1 /* Last entry: no conflict with kernel text */
lis r9,MAS0_TLBSEL(1)@h
rlwimi r9,r10,16,4,15 /* Setup MAS0 = TLBSEL | ESEL(r9) */
/* Set up a temp identity mapping v:0 to p:0 and return to it. */
#if defined(CONFIG_SMP) || defined(CONFIG_PPC_E500MC)
#define M_IF_NEEDED MAS2_M
#else
#define M_IF_NEEDED 0
#endif
mtspr SPRN_MAS0,r9
lis r9,(MAS1_VALID|MAS1_IPROT)@h
ori r9,r9,(MAS1_TSIZE(BOOK3E_PAGESZ_1GB))@l
mtspr SPRN_MAS1,r9
LOAD_REG_IMMEDIATE(r9, 0x0 | M_IF_NEEDED)
mtspr SPRN_MAS2,r9
LOAD_REG_IMMEDIATE(r9, 0x0 | MAS3_SR | MAS3_SW | MAS3_SX)
mtspr SPRN_MAS3,r9
li r9,0
mtspr SPRN_MAS7,r9
tlbwe
isync
blr
#endif
/* kexec_smp_wait(void)
*
* call with interrupts off
* note: this is a terminal routine, it does not save lr
*
* get phys id from paca
* switch to real mode
* mark the paca as no longer used
* join other cpus in kexec_wait(phys_id)
*/
_GLOBAL(kexec_smp_wait)
lhz r3,PACAHWCPUID(r13)
bl real_mode
li r4,KEXEC_STATE_REAL_MODE
stb r4,PACAKEXECSTATE(r13)
SYNC
b kexec_wait
/*
* switch to real mode (turn mmu off)
* we use the early kernel trick that the hardware ignores bits
* 0 and 1 (big endian) of the effective address in real mode
*
* don't overwrite r3 here, it is live for kexec_wait above.
*/
real_mode: /* assume normal blr return */
#ifdef CONFIG_PPC_BOOK3E
/* Create an identity mapping. */
b kexec_create_tlb
#else
1: li r9,MSR_RI
li r10,MSR_DR|MSR_IR
mflr r11 /* return address to SRR0 */
mfmsr r12
andc r9,r12,r9
andc r10,r12,r10
mtmsrd r9,1
mtspr SPRN_SRR1,r10
mtspr SPRN_SRR0,r11
rfid
#endif
/*
* kexec_sequence(newstack, start, image, control, clear_all(),
copy_with_mmu_off)
*
* does the grungy work with stack switching and real mode switches
* also does simple calls to other code
*/
_GLOBAL(kexec_sequence)
mflr r0
std r0,16(r1)
/* switch stacks to newstack -- &kexec_stack.stack */
stdu r1,THREAD_SIZE-STACK_FRAME_OVERHEAD(r3)
mr r1,r3
li r0,0
std r0,16(r1)
BEGIN_FTR_SECTION
/*
* This is the best time to turn AMR/IAMR off.
* key 0 is used in radix for supervisor<->user
* protection, but on hash key 0 is reserved
* ideally we want to enter with a clean state.
* NOTE, we rely on r0 being 0 from above.
*/
mtspr SPRN_IAMR,r0
BEGIN_FTR_SECTION_NESTED(42)
mtspr SPRN_AMOR,r0
END_FTR_SECTION_NESTED_IFSET(CPU_FTR_HVMODE, 42)
END_FTR_SECTION_IFSET(CPU_FTR_ARCH_300)
/* save regs for local vars on new stack.
* yes, we won't go back, but ...
*/
std r31,-8(r1)
std r30,-16(r1)
std r29,-24(r1)
std r28,-32(r1)
std r27,-40(r1)
std r26,-48(r1)
std r25,-56(r1)
stdu r1,-STACK_FRAME_OVERHEAD-64(r1)
/* save args into preserved regs */
mr r31,r3 /* newstack (both) */
mr r30,r4 /* start (real) */
mr r29,r5 /* image (virt) */
mr r28,r6 /* control, unused */
mr r27,r7 /* clear_all() fn desc */
mr r26,r8 /* copy_with_mmu_off */
lhz r25,PACAHWCPUID(r13) /* get our phys cpu from paca */
/* disable interrupts, we are overwriting kernel data next */
#ifdef CONFIG_PPC_BOOK3E
wrteei 0
#else
mfmsr r3
rlwinm r3,r3,0,17,15
mtmsrd r3,1
#endif
/* We need to turn the MMU off unless we are in hash mode
* under a hypervisor
*/
cmpdi r26,0
beq 1f
bl real_mode
1:
/* copy dest pages, flush whole dest image */
mr r3,r29
bl kexec_copy_flush /* (image) */
/* turn off mmu now if not done earlier */
cmpdi r26,0
bne 1f
bl real_mode
/* copy 0x100 bytes starting at start to 0 */
1: li r3,0
mr r4,r30 /* start, aka phys mem offset */
li r5,0x100
li r6,0
bl copy_and_flush /* (dest, src, copy limit, start offset) */
1: /* assume normal blr return */
/* release other cpus to the new kernel secondary start at 0x60 */
mflr r5
li r6,1
stw r6,kexec_flag-1b(5)
cmpdi r27,0
beq 1f
/* clear out hardware hash page table and tlb */
#ifdef PPC64_ELF_ABI_v1
ld r12,0(r27) /* deref function descriptor */
#else
mr r12,r27
#endif
mtctr r12
bctrl /* mmu_hash_ops.hpte_clear_all(void); */
/*
* kexec image calling is:
* the first 0x100 bytes of the entry point are copied to 0
*
* all slaves branch to slave = 0x60 (absolute)
* slave(phys_cpu_id);
*
* master goes to start = entry point
* start(phys_cpu_id, start, 0);
*
*
* a wrapper is needed to call existing kernels, here is an approximate
* description of one method:
*
* v2: (2.6.10)
* start will be near the boot_block (maybe 0x100 bytes before it?)
* it will have a 0x60, which will b to boot_block, where it will wait
* and 0 will store phys into struct boot-block and load r3 from there,
* copy kernel 0-0x100 and tell slaves to back down to 0x60 again
*
* v1: (2.6.9)
* boot block will have all cpus scanning device tree to see if they
* are the boot cpu ?????
* other device tree differences (prop sizes, va vs pa, etc)...
*/
1: mr r3,r25 # my phys cpu
mr r4,r30 # start, aka phys mem offset
mtlr 4
li r5,0
blr /* image->start(physid, image->start, 0); */
#endif /* CONFIG_KEXEC_CORE */
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