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linux-next/arch/s390/kernel/base.S
Michael Holzheu fa7c004342 s390/kdump: Use real mode for PSW restart and kexec
Currently the PSW restart handler and kexec are executed in real
mode with DAT=off. For kexec/kdump the function setup_regs() is
called that uses the per-cpu variable "crash_notes". Because
there are situations when the per-cpu implementation uses vmalloc
memory, calling setup_regs() in real mode can cause a program
check interrupt.

To fix that problem this patch changes the following:

* Ensure that diag308_reset() does not change PSW bits to real mode
* Enable DAT in __do_restart() after we switched to an online CPU
* Enable DAT in __machine_kexec() after we switched to the IPL CPU
* Call setup_regs() before we switch to real mode and call purgatory

Reviewed-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2012-05-23 17:06:51 +02:00

206 lines
4.1 KiB
ArmAsm

/*
* arch/s390/kernel/base.S
*
* Copyright IBM Corp. 2006,2007
* Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>
* Michael Holzheu <holzheu@de.ibm.com>
*/
#include <linux/linkage.h>
#include <asm/asm-offsets.h>
#include <asm/ptrace.h>
#ifdef CONFIG_64BIT
ENTRY(s390_base_mcck_handler)
basr %r13,0
0: lg %r15,__LC_PANIC_STACK # load panic stack
aghi %r15,-STACK_FRAME_OVERHEAD
larl %r1,s390_base_mcck_handler_fn
lg %r1,0(%r1)
ltgr %r1,%r1
jz 1f
basr %r14,%r1
1: la %r1,4095
lmg %r0,%r15,__LC_GPREGS_SAVE_AREA-4095(%r1)
lpswe __LC_MCK_OLD_PSW
.section .bss
.align 8
.globl s390_base_mcck_handler_fn
s390_base_mcck_handler_fn:
.quad 0
.previous
ENTRY(s390_base_ext_handler)
stmg %r0,%r15,__LC_SAVE_AREA_ASYNC
basr %r13,0
0: aghi %r15,-STACK_FRAME_OVERHEAD
larl %r1,s390_base_ext_handler_fn
lg %r1,0(%r1)
ltgr %r1,%r1
jz 1f
basr %r14,%r1
1: lmg %r0,%r15,__LC_SAVE_AREA_ASYNC
ni __LC_EXT_OLD_PSW+1,0xfd # clear wait state bit
lpswe __LC_EXT_OLD_PSW
.section .bss
.align 8
.globl s390_base_ext_handler_fn
s390_base_ext_handler_fn:
.quad 0
.previous
ENTRY(s390_base_pgm_handler)
stmg %r0,%r15,__LC_SAVE_AREA_SYNC
basr %r13,0
0: aghi %r15,-STACK_FRAME_OVERHEAD
larl %r1,s390_base_pgm_handler_fn
lg %r1,0(%r1)
ltgr %r1,%r1
jz 1f
basr %r14,%r1
lmg %r0,%r15,__LC_SAVE_AREA_SYNC
lpswe __LC_PGM_OLD_PSW
1: lpswe disabled_wait_psw-0b(%r13)
.align 8
disabled_wait_psw:
.quad 0x0002000180000000,0x0000000000000000 + s390_base_pgm_handler
.section .bss
.align 8
.globl s390_base_pgm_handler_fn
s390_base_pgm_handler_fn:
.quad 0
.previous
#
# Calls diag 308 subcode 1 and continues execution
#
# The following conditions must be ensured before calling this function:
# * Prefix register = 0
# * Lowcore protection is disabled
#
ENTRY(diag308_reset)
larl %r4,.Lctlregs # Save control registers
stctg %c0,%c15,0(%r4)
larl %r4,.Lfpctl # Floating point control register
stfpc 0(%r4)
larl %r4,.Lcontinue_psw # Save PSW flags
epsw %r2,%r3
stm %r2,%r3,0(%r4)
larl %r4,.Lrestart_psw # Setup restart PSW at absolute 0
lghi %r3,0
lg %r4,0(%r4) # Save PSW
sturg %r4,%r3 # Use sturg, because of large pages
lghi %r1,1
diag %r1,%r1,0x308
.Lrestart_part2:
lhi %r0,0 # Load r0 with zero
lhi %r1,2 # Use mode 2 = ESAME (dump)
sigp %r1,%r0,0x12 # Switch to ESAME mode
sam64 # Switch to 64 bit addressing mode
larl %r4,.Lctlregs # Restore control registers
lctlg %c0,%c15,0(%r4)
larl %r4,.Lfpctl # Restore floating point ctl register
lfpc 0(%r4)
larl %r4,.Lcontinue_psw # Restore PSW flags
lpswe 0(%r4)
.Lcontinue:
br %r14
.align 16
.Lrestart_psw:
.long 0x00080000,0x80000000 + .Lrestart_part2
.section .data..nosave,"aw",@progbits
.align 8
.Lcontinue_psw:
.quad 0,.Lcontinue
.previous
.section .bss
.align 8
.Lctlregs:
.rept 16
.quad 0
.endr
.Lfpctl:
.long 0
.previous
#else /* CONFIG_64BIT */
ENTRY(s390_base_mcck_handler)
basr %r13,0
0: l %r15,__LC_PANIC_STACK # load panic stack
ahi %r15,-STACK_FRAME_OVERHEAD
l %r1,2f-0b(%r13)
l %r1,0(%r1)
ltr %r1,%r1
jz 1f
basr %r14,%r1
1: lm %r0,%r15,__LC_GPREGS_SAVE_AREA
lpsw __LC_MCK_OLD_PSW
2: .long s390_base_mcck_handler_fn
.section .bss
.align 4
.globl s390_base_mcck_handler_fn
s390_base_mcck_handler_fn:
.long 0
.previous
ENTRY(s390_base_ext_handler)
stm %r0,%r15,__LC_SAVE_AREA_ASYNC
basr %r13,0
0: ahi %r15,-STACK_FRAME_OVERHEAD
l %r1,2f-0b(%r13)
l %r1,0(%r1)
ltr %r1,%r1
jz 1f
basr %r14,%r1
1: lm %r0,%r15,__LC_SAVE_AREA_ASYNC
ni __LC_EXT_OLD_PSW+1,0xfd # clear wait state bit
lpsw __LC_EXT_OLD_PSW
2: .long s390_base_ext_handler_fn
.section .bss
.align 4
.globl s390_base_ext_handler_fn
s390_base_ext_handler_fn:
.long 0
.previous
ENTRY(s390_base_pgm_handler)
stm %r0,%r15,__LC_SAVE_AREA_SYNC
basr %r13,0
0: ahi %r15,-STACK_FRAME_OVERHEAD
l %r1,2f-0b(%r13)
l %r1,0(%r1)
ltr %r1,%r1
jz 1f
basr %r14,%r1
lm %r0,%r15,__LC_SAVE_AREA_SYNC
lpsw __LC_PGM_OLD_PSW
1: lpsw disabled_wait_psw-0b(%r13)
2: .long s390_base_pgm_handler_fn
disabled_wait_psw:
.align 8
.long 0x000a0000,0x00000000 + s390_base_pgm_handler
.section .bss
.align 4
.globl s390_base_pgm_handler_fn
s390_base_pgm_handler_fn:
.long 0
.previous
#endif /* CONFIG_64BIT */