linux.git/arch/s390/boot, branch v5.12

s390: uv: Fix sysfs max number of VCPUs reporting

2021-01-27T12:00:04+00:00

The number reported by the query is N-1 and I think people reading the
sysfs file would expect N instead. For users creating VMs there's no
actual difference because KVM's limit is currently below the UV's
limit.

Signed-off-by: Janosch Frank 
Fixes: a0f60f8431999 ("s390/protvirt: Add sysfs firmware interface for Ultravisor information")
Cc: stable@vger.kernel.org
Reviewed-by: Claudio Imbrenda 
Acked-by: Cornelia Huck 
Signed-off-by: Vasily Gorbik

kasan, x86, s390: update undef CONFIG_KASAN

2020-12-22T20:55:08+00:00

With the intoduction of hardware tag-based KASAN some kernel checks of
this kind:

  ifdef CONFIG_KASAN

will be updated to:

  if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)

x86 and s390 use a trick to #undef CONFIG_KASAN for some of the code
that isn't linked with KASAN runtime and shouldn't have any KASAN
annotations.

Also #undef CONFIG_KASAN_GENERIC with CONFIG_KASAN.

Link: https://lkml.kernel.org/r/9d84bfaaf8fabe0fc89f913c9e420a30bd31a260.1606161801.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov 
Signed-off-by: Vincenzo Frascino 
Reviewed-by: Marco Elver 
Acked-by: Vasily Gorbik 
Reviewed-by: Alexander Potapenko 
Tested-by: Vincenzo Frascino 
Cc: Andrey Ryabinin 
Cc: Branislav Rankov 
Cc: Catalin Marinas 
Cc: Dmitry Vyukov 
Cc: Evgenii Stepanov 
Cc: Kevin Brodsky 
Cc: Will Deacon 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

s390/boot: add build-id to decompressor

2020-12-09T20:02:07+00:00

More and more functionality from the early boot phase gets carried over
to the decompressor. With this the complexity of the code and thus the
chance to introduce bugs increases. In order to be able to debug these
early boot bugs the distributions have to package the decompressors
vmlinux together with the other debuginfos. However for that the
distributions require the vmlinux to contain a build-id.

Per default the section containing the build-id is placed first in the
section table. So make sure to move it behind the .text section
otherwise the image would be unbootable.

Signed-off-by: Philipp Rudo 
Signed-off-by: Heiko Carstens

s390/decompressor: print cmdline and BEAR on pgm_check

2020-11-20T18:19:11+00:00

Add kernel command line and last breaking event.
The kernel command line is taken from early_command_line and printed
only if kernel is not running as protected virtualization guest and
if it has been already initialized from the "COMMAND_LINE".

Linux version 5.10.0-rc3-22794-gecaa72788df0-dirty (gor@tuxmaker) #28 SMP PREEMPT Mon Nov 9 17:41:20 CET 2020
Kernel command line: audit_enable=0 audit=0 selinux=0 crashkernel=296M root=/dev/dasda1 dasd=ec5b
memblock=debug die
Kernel fault: interruption code 0005 ilc:2
PSW : 0000000180000000 0000000000012f92 (parse_boot_command_line+0x27a/0x46c)
      R:0 T:0 IO:0 EX:0 Key:0 M:0 W:0 P:0 AS:0 CC:0 PM:0 RI:0 EA:3
GPRS: 0000000000000000 00ffffffffffffff 0000000000000000 000000000001a65c
      000000000000bf60 0000000000000000 00000000000003c0 0000000000000000
      0000000000000080 000000000002322d 000000007f29ef20 0000000000efd018
      000000000311c000 0000000000010070 0000000000012f82 000000000000bea8
Call Trace:
(sp:000000000000bea8 [<000000000002016e>] 000000000002016e)
 sp:000000000000bf18 [<0000000000012408>] startup_kernel+0x88/0x2fc
 sp:000000000000bf60 [<00000000000100c4>] startup_normal+0xb0/0xb0
Last Breaking-Event-Address:
 [<00000000000135ba>] strcmp+0x22/0x24

Reviewed-by: Alexander Egorenkov 
Acked-by: Viktor Mihajlovski 
Signed-off-by: Vasily Gorbik 
Signed-off-by: Heiko Carstens

s390/decompressor: add stacktrace support

2020-11-20T18:19:11+00:00

Decompressor works on a single statically allocated stack. Stacktrace
implementation with -mbackchain just takes few lines of code.

Linux version 5.10.0-rc3-22793-g0f84a355b776-dirty (gor@tuxmaker) #27 SMP PREEMPT Mon Nov 9 17:30:18 CET 2020
Kernel fault: interruption code 0005 ilc:2
PSW : 0000000180000000 0000000000012f92 (parse_boot_command_line+0x27a/0x46c)
      R:0 T:0 IO:0 EX:0 Key:0 M:0 W:0 P:0 AS:0 CC:0 PM:0 RI:0 EA:3
GPRS: 0000000000000000 00ffffffffffffff 0000000000000000 000000000001a62c
      000000000000bf60 0000000000000000 00000000000003c0 0000000000000000
      0000000000000080 000000000002322d 000000007f29ef20 0000000000efd018
      000000000311c000 0000000000010070 0000000000012f82 000000000000bea8
Call Trace:
(sp:000000000000bea8 [<000000000002016e>] 000000000002016e)
 sp:000000000000bf18 [<0000000000012408>] startup_kernel+0x88/0x2fc
 sp:000000000000bf60 [<00000000000100c4>] startup_normal+0xb0/0xb0

Reviewed-by: Alexander Egorenkov 
Signed-off-by: Vasily Gorbik 
Signed-off-by: Heiko Carstens

s390/decompressor: add symbols support

2020-11-20T18:19:11+00:00

Information printed by print_pgm_check_info() is crucial for
debugging decompressor problems. Printing instruction addresses is
better than nothing, but turns further debugging into tedious job of
figuring out which function those addresses correspond to.

This change adds simplistic symbols resolution support. And adds %pS
format specifier support to decompressor_printk().

Decompressor symbols list is extracted and sorted with
nm -n -S:
...
0000000000010000 0000000000000014 T startup
0000000000010014 00000000000000b0 t startup_normal
0000000000010180 00000000000000b2 t startup_kdump
...

Then functions are filtered and contracted to a form:
"10000 14 startup\0""10014 b0 startup_normal\0""10180 b2 startup_kdump\0"
...
Which makes it trivial to find beginning of an entry and names are 0
terminated, so could be used as is. Symbols are binary-searched.

To get symbols list with final addresses and then get it into the
decompressor's image the same trick as for kallsyms is used.
Decompressor's vmlinux is linked twice.

Symbols are stored in .decompressor.syms section, current size is about
2kb.

Reviewed-by: Alexander Egorenkov 
Signed-off-by: Vasily Gorbik 
Signed-off-by: Heiko Carstens

s390/decompressor: correct some asm symbols annotations

2020-11-20T18:19:11+00:00

Use SYM_CODE_* annotations for asm functions, so that function lengths
are recognized correctly.

Also currently the most part of startup is marked as startup_kdump. Move
misplaced startup_kdump where it belongs.

$ nm -n -S arch/s390/boot/compressed/vmlinux
Before:
0000000000010000 T startup
0000000000010010 T startup_kdump
After:
0000000000010000 0000000000000014 T startup
0000000000010014 00000000000000b0 t startup_normal
0000000000010180 00000000000000b2 t startup_kdump

Reviewed-by: Alexander Egorenkov 
Signed-off-by: Vasily Gorbik 
Signed-off-by: Heiko Carstens

s390/decompressor: add decompressor_printk

2020-11-20T18:19:11+00:00

The decompressor does not have any special debug means. Running the
kernel under qemu with gdb is helpful but tedious exercise if done
repeatedly. It is also not applicable to debugging under LPAR and z/VM.

One special thing which stands out is a working sclp_early_printk,
which could be used once the kernel switches to 64-bit addressing mode.

But sclp_early_printk does not provide any string formating capabilities.
Formatting and printing string without printk-alike function is a
not fun. The lack of printk-alike function means people would save up on
testing and introduce more bugs.

So, finally, provide decompressor_printk function, which fits on one
screen and trades features for simplicity.

It only supports "%s", "%x" and "%lx" specifiers and zero padding for
hex values.

Reviewed-by: Alexander Egorenkov 
Signed-off-by: Vasily Gorbik 
Signed-off-by: Heiko Carstens

s390: unify identity mapping limits handling

2020-11-20T18:19:10+00:00

Currently we have to consider too many different values which
in the end only affect identity mapping size. These are:
1. max_physmem_end - end of physical memory online or standby.
   Always <= end of the last online memory block (get_mem_detect_end()).
2. CONFIG_MAX_PHYSMEM_BITS - the maximum size of physical memory the
   kernel is able to support.
3. "mem=" kernel command line option which limits physical memory usage.
4. OLDMEM_BASE which is a kdump memory limit when the kernel is executed as
   crash kernel.
5. "hsa" size which is a memory limit when the kernel is executed during
   zfcp/nvme dump.

Through out kernel startup and run we juggle all those values at once
but that does not bring any amusement, only confusion and complexity.

Unify all those values to a single one we should really care, that is
our identity mapping size.

Signed-off-by: Vasily Gorbik 
Reviewed-by: Alexander Gordeev 
Acked-by: Heiko Carstens 
Signed-off-by: Heiko Carstens

s390/early: rewrite program parameter setup in C

2020-11-09T10:21:00+00:00

And move it earlier in the decompressor.

Reviewed-by: Heiko Carstens 
Signed-off-by: Vasily Gorbik 
Signed-off-by: Heiko Carstens