From fa7c0043425624ed65b94a6fabe750c7b0af8719 Mon Sep 17 00:00:00 2001 From: Michael Holzheu Date: Mon, 21 May 2012 11:30:30 +0200 Subject: [PATCH] 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 Signed-off-by: Michael Holzheu Signed-off-by: Martin Schwidefsky --- arch/s390/kernel/base.S | 12 ++++++++++++ arch/s390/kernel/ipl.c | 1 + arch/s390/kernel/machine_kexec.c | 3 ++- 3 files changed, 15 insertions(+), 1 deletion(-) diff --git a/arch/s390/kernel/base.S b/arch/s390/kernel/base.S index 3aa4d00..c880ff7 100644 --- a/arch/s390/kernel/base.S +++ b/arch/s390/kernel/base.S @@ -88,6 +88,9 @@ ENTRY(diag308_reset) 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 @@ -103,11 +106,20 @@ ENTRY(diag308_reset) 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: diff --git a/arch/s390/kernel/ipl.c b/arch/s390/kernel/ipl.c index 8342e65..dcfdcb3 100644 --- a/arch/s390/kernel/ipl.c +++ b/arch/s390/kernel/ipl.c @@ -1750,6 +1750,7 @@ static struct kobj_attribute on_restart_attr = static void __do_restart(void *ignore) { + __arch_local_irq_stosm(0x04); /* enable DAT */ smp_send_stop(); #ifdef CONFIG_CRASH_DUMP crash_kexec(NULL); diff --git a/arch/s390/kernel/machine_kexec.c b/arch/s390/kernel/machine_kexec.c index 03d2027..cdacf8f 100644 --- a/arch/s390/kernel/machine_kexec.c +++ b/arch/s390/kernel/machine_kexec.c @@ -80,8 +80,8 @@ static void __do_machine_kdump(void *image) #ifdef CONFIG_CRASH_DUMP int (*start_kdump)(int) = (void *)((struct kimage *) image)->start; - __load_psw_mask(PSW_MASK_BASE | PSW_DEFAULT_KEY | PSW_MASK_EA | PSW_MASK_BA); setup_regs(); + __load_psw_mask(PSW_MASK_BASE | PSW_DEFAULT_KEY | PSW_MASK_EA | PSW_MASK_BA); start_kdump(1); #endif } @@ -214,6 +214,7 @@ static void __machine_kexec(void *data) { struct kimage *image = data; + __arch_local_irq_stosm(0x04); /* enable DAT */ pfault_fini(); tracing_off(); debug_locks_off(); -- 2.7.4