From: Michael Holzheu <holzheu@xxxxxxxxxxxxxxxxxx>
The diagnose 308 call is the prefered method for clearing all ongoing I/O.
Therefore if it is available we use it instead of doing a manual reset.
Signed-off-by: Michael Holzheu <holzheu@xxxxxxxxxxxxxxxxxx>
---
arch/s390/include/asm/ipl.h | 1 +
arch/s390/kernel/base.S | 36 ++++++++++++++++++++++++++++++++++++
arch/s390/kernel/ipl.c | 6 ++++++
3 files changed, 43 insertions(+)
--- a/arch/s390/include/asm/ipl.h
+++ b/arch/s390/include/asm/ipl.h
@@ -167,5 +167,6 @@ enum diag308_rc {
};
extern int diag308(unsigned long subcode, void *addr);
+extern void diag308_reset(void);
#endif /* _ASM_S390_IPL_H */
--- a/arch/s390/kernel/base.S
+++ b/arch/s390/kernel/base.S
@@ -76,6 +76,42 @@ 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,.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)
+ br %r14
+.align 16
+.Lrestart_psw:
+ .long 0x00080000,0x80000000 + .Lrestart_part2
+
+ .section .bss
+.align 8
+.Lctlregs:
+ .rept 16
+ .quad 0
+ .endr
+ .previous
+
#else /* CONFIG_64BIT */
ENTRY(s390_base_mcck_handler)
--- a/arch/s390/kernel/ipl.c
+++ b/arch/s390/kernel/ipl.c
@@ -1996,6 +1996,12 @@ static void do_reset_calls(void)
{
struct reset_call *reset;
+#ifdef CONFIG_64BIT
+ if (diag308_set_works) {
+ diag308_reset();
+ return;
+ }
+#endif
list_for_each_entry(reset, &rcall, list)
reset->fn();
}
--
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