s390: memory detection > 32GB.
PATCH 14/16 s390: memory detection > 32GB.
[patch 14/16] s390: memory detection > 32GB.
From: Heiko Carstens <[email protected]>
The kernel takes a very long time to boot if the memory size is bigger then 32767 MB. The memory size is contained in a structure created by an sclp call. The kernel accesses the field with a LH instrution which performs a sign extension of a 16 bit word. In the case of a memory size with bit 2^15 set this results in a very large value and the memory detection just loops for a long time. In addition if more then 64 GB are used on a 64 bit system the memory size is read from an incorrect storage location.
Use zero-extention to read the 16 bit memory size and the correct offset to read the 4 byte memory size on 64 bit.
diffstat:
arch/s390/kernel/head.S | 8 ++++---- arch/s390/kernel/head64.S | 6 +++--- 2 files changed, 7 insertions(+), 7 deletions(-)
arch/s390/kernel/head64.S +3 -3
@@ -518,9 +518,9 @@ startup:basr %r13,0 l %r2,.Lrcp2-.LPG1(%r13) # try with Read SCP b .Lservicecall-.LPG1(%r13) .Lprocsccb: - lh %r1,.Lscpincr1-PARMAREA(%r4) # use this one if != 0 - chi %r1,0x00 - jne .Lscnd + lghi %r1,0 + icm %r1,3,.Lscpincr1-PARMAREA(%r4) # use this one if != 0 + jnz .Lscnd lg %r1,.Lscpincr2-PARMAREA(%r4) # otherwise use this one .Lscnd: xr %r3,%r3 # same logic
arch/s390/kernel/head.S +4 -4
@@ -517,10 +517,10 @@ startup:basr %r13,0 l %r2, .Lrcp2-.LPG1(%r13) # try with Read SCP b .Lservicecall-.LPG1(%r13) .Lprocsccb: - lh %r1,.Lscpincr1-PARMAREA(%r4) # use this one if != 0 - chi %r1,0x00 - jne .Lscnd - l %r1,.Lscpincr2-PARMAREA(%r4) # otherwise use this one + lhi %r1,0 + icm %r1,3,.Lscpincr1-PARMAREA(%r4) # use this one if != 0 + jnz .Lscnd + l %r1,.Lscpincr2-PARMAREA+4(%r4) # otherwise use this one .Lscnd: xr %r3,%r3 # same logic ic %r3,.Lscpa1-PARMAREA(%r4)