s390/head: set io/ext handlers to disabled wait

Set io/ext handlers to disabled wait in the initial lowcore, so that they
are effective right from the kernel start, when a boot method used does
not rewrite this part of the lowcore for its own needs (i.e. kexec, z/vm
ipl reader boot, qemu direct boot, load from removable media or server).

When the kernel is loaded by zipl, scsi loader or qemu loader, some or
all of the io/ext/pgm handlers addresses might be rewritten. Rewrite them
to initial values again as early as possible.

Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

diff --git a/arch/s390/boot/head.S b/arch/s390/boot/head.S
index 1a2c2b1..bc34ad2 100644 (file)
--- a/arch/s390/boot/head.S
+++ b/arch/s390/boot/head.S
@@ -62,8 +62,12 @@ __HEAD
 
        .org    __LC_RST_NEW_PSW                # 0x1a0
        .quad   0,iplstart
+       .org    __LC_EXT_NEW_PSW                # 0x1b0
+       .quad   0x0002000180000000,0x1b0        # disabled wait
        .org    __LC_PGM_NEW_PSW                # 0x1d0
        .quad   0x0000000180000000,startup_pgm_check_handler
+       .org    __LC_IO_NEW_PSW                 # 0x1f0
+       .quad   0x0002000180000000,0x1f0        # disabled wait
 
        .org    0x200
 
@@ -303,6 +307,9 @@ ENTRY(startup_kdump)
        sam64                           # switch to 64 bit addressing mode
        basr    %r13,0                  # get base
 .LPG0:
+       mvc     __LC_EXT_NEW_PSW(16),.Lext_new_psw-.LPG0(%r13)
+       mvc     __LC_PGM_NEW_PSW(16),.Lpgm_new_psw-.LPG0(%r13)
+       mvc     __LC_IO_NEW_PSW(16),.Lio_new_psw-.LPG0(%r13)
        xc      0x200(256),0x200        # partially clear lowcore
        xc      0x300(256),0x300
        xc      0xe00(256),0xe00
@@ -320,7 +327,12 @@ ENTRY(startup_kdump)
        .long   0x8000 + (1<<(PAGE_SHIFT+BOOT_STACK_ORDER)) - STACK_FRAME_OVERHEAD
        .align  8
 6:     .long   0x7fffffff,0xffffffff
-
+.Lext_new_psw:
+       .quad   0x0002000180000000,0x1b0        # disabled wait
+.Lpgm_new_psw:
+       .quad   0x0000000180000000,startup_pgm_check_handler
+.Lio_new_psw:
+       .quad   0x0002000180000000,0x1f0        # disabled wait
 .Lctl: .quad   0x04040000              # cr0: AFP registers & secondary space
        .quad   0                       # cr1: primary space segment table
        .quad   .Lduct                  # cr2: dispatchable unit control table