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| author | Christian Borntraeger <borntraeger@de.ibm.com> | 2017-11-22 15:26:27 +0100 |
|---|---|---|
| committer | Cornelia Huck <cohuck@redhat.com> | 2017-12-14 17:56:54 +0100 |
| commit | 339686a358b11a231aa5b6d1424e7a1460d7f277 (patch) | |
| tree | 9c017fd7c61e3b0c37038dd8655a665d9d1dabcc /pc-bios/s390-ccw/start.S | |
| parent | 39b28b26cf5b7d397bbc5cd1750971efad331b4b (diff) | |
| download | qemu-339686a358b11a231aa5b6d1424e7a1460d7f277.zip qemu-339686a358b11a231aa5b6d1424e7a1460d7f277.tar.gz qemu-339686a358b11a231aa5b6d1424e7a1460d7f277.tar.bz2 | |
pc-bios/s390-ccw: zero out bss section
The QEMU ELF loader does not zero the bss segment.
This resulted in several bugs, e.g. see
commit 5d739a4787a5 (s390-ccw.img: Fix sporadic errors with ccw boot image - initialize css)
commit 6a40fa2669d3 (s390-ccw.img: Initialize next_idx)
commit 8775d91a0f42 (pc-bios/s390-ccw: Fix problem with invalid virtio-scsi LUN when rebooting)
Let's fix this once and forever by letting the BIOS zero the bss itself.
Suggested-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Message-Id: <20171122142627.73170-3-borntraeger@de.ibm.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>
Diffstat (limited to 'pc-bios/s390-ccw/start.S')
| -rw-r--r-- | pc-bios/s390-ccw/start.S | 30 |
1 files changed, 27 insertions, 3 deletions
diff --git a/pc-bios/s390-ccw/start.S b/pc-bios/s390-ccw/start.S index 43f9bd2..eb8d024 100644 --- a/pc-bios/s390-ccw/start.S +++ b/pc-bios/s390-ccw/start.S @@ -3,7 +3,7 @@ * into the pc-bios directory of qemu. * * Copyright (c) 2013 Alexander Graf <agraf@suse.de> - * Copyright 2013 IBM Corp. + * Copyright IBM Corp. 2013, 2017 * * This work is licensed under the terms of the GNU GPL, version 2 or (at * your option) any later version. See the COPYING file in the top-level @@ -13,8 +13,32 @@ .globl _start _start: -larl %r15, stack + 0x8000 /* Set up stack */ -j main /* And call C */ + larl %r15, stack + 0x8000 /* Set up stack */ + + /* clear bss */ + larl %r2, __bss_start + larl %r3, _end + slgr %r3, %r2 /* get sizeof bss */ + ltgr %r3,%r3 /* bss emtpy? */ + jz done + aghi %r3,-1 + srlg %r4,%r3,8 /* how many 256 byte chunks? */ + ltgr %r4,%r4 + lgr %r1,%r2 + jz remainder +loop: + xc 0(256,%r1),0(%r1) + la %r1,256(%r1) + brctg %r4,loop +remainder: + larl %r2,memsetxc + ex %r3,0(%r2) +done: + j main /* And call C */ + +memsetxc: + xc 0(1,%r1),0(%r1) + /* * void disabled_wait(void) |