s390: fix various typos

Fix various typos found with codespell.

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>

s390: consistently use .balign instead of .align

The .align directive has inconsistent behavior across architectures. Use
.balign instead everywhere. This is a no-op for s390, but with this there
is

s390: consistently use .balign instead of .align

The .align directive has inconsistent behavior across architectures. Use
.balign instead everywhere. This is a no-op for s390, but with this there
is no mix in using .align and .balign anymore.

Future code is supposed to use only .balign.

Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>

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s390/head: get rid of 31 bit leftovers

Get rid of old 31 bit leftovers within ipl code:

- convert everything to pc relative code
- use 64 bit addressing mode as early as possible
- use 64 bit arith

s390/head: get rid of 31 bit leftovers

Get rid of old 31 bit leftovers within ipl code:

- convert everything to pc relative code
- use 64 bit addressing mode as early as possible
- use 64 bit arithmetics wherever possible

This way the code doesn't look as odd as before anymore.

Reviewed-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

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s390/boot: workaround llvm IAS bug

For at least the mvc and clc instructions llvm's integrated assembler can
generate incorrect code. In particular this happens with decompressor boot
code. The reas

s390/boot: workaround llvm IAS bug

For at least the mvc and clc instructions llvm's integrated assembler can
generate incorrect code. In particular this happens with decompressor boot
code. The reason seems to be that relocations for the second displacement
of each instruction are at incorrect locations (-/+: gas vs llvm IAS):

mvc __LC_IO_NEW_PSW(16),.Lnewpsw

results in

4: d2 0f 01 f0 00 00 mvc 496(16,%r0),0
- 8: R_390_12 .head.text+0x10
+ 6: R_390_12 .head.text+0x10

and
clc 0(3,%r4),.L_hdr
results in

258: d5 02 40 00 00 00 clc 0(3,%r4),0
- 25c: R_390_12 .head.text+0x324
+ 25a: R_390_12 .head.text+0x324

Workaround this by writing the code in a different way.

Tested-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Link: https://github.com/llvm/llvm-project/issues/55411
Link: https://lore.kernel.org/r/20220511120532.2228616-7-hca@linux.ibm.com
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

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s390/boot: convert parmarea to C

Convert parmarea to C, which makes it much easier to initialize it. No need
to keep offsets in assembler code in sync with struct parmarea anymore.

Reviewed-by: Vas

s390/boot: convert parmarea to C

Convert parmarea to C, which makes it much easier to initialize it. No need
to keep offsets in assembler code in sync with struct parmarea anymore.

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

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s390/boot: convert initial lowcore to C

Convert initial lowcore to C and use proper defines and structures to
initialize it. This should make the z/VM ipl procedure a bit less magic.

Acked-by: Pete

s390/boot: convert initial lowcore to C

Convert initial lowcore to C and use proper defines and structures to
initialize it. This should make the z/VM ipl procedure a bit less magic.

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

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s390/head: initialize all new psws

Initialize all new psws with disabled wait psws, except for the restart new
psw. This way every unexpected exception, svc, machine check, or interrupt
is handled p

s390/head: initialize all new psws

Initialize all new psws with disabled wait psws, except for the restart new
psw. This way every unexpected exception, svc, machine check, or interrupt
is handled properly.

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

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s390/boot: change initial program check handler to disabled wait psw

The program check handler of the kernel image points to
startup_pgm_check_handler. However an early program check which happens
w

s390/boot: change initial program check handler to disabled wait psw

The program check handler of the kernel image points to
startup_pgm_check_handler. However an early program check which happens
while loading the kernel image will jump to potentially random code, since
the code of the program check handler is not yet loaded; leading to a
program check loop.

Therefore initialize it to a disabled wait psw and let the startup code set
the proper psw when everything is in memory.

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

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s390/head: adjust iplstart entry point

Move iplstart entry point to 0x200 again, instead of the middle of the ipl
code. This way even the comment describing the ccw program is correct
again.

Acked-

s390/head: adjust iplstart entry point

Move iplstart entry point to 0x200 again, instead of the middle of the ipl
code. This way even the comment describing the ccw program is correct
again.

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

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s390: remove invalid email address of Heiko Carstens

Remove my old invalid email address which can be found in a couple of
files. Instead of updating it, just remove my contact data completely
from

s390: remove invalid email address of Heiko Carstens

Remove my old invalid email address which can be found in a couple of
files. Instead of updating it, just remove my contact data completely
from source files.
We have git and other tools which allow to figure out who is responsible
for what with recent contact data.

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

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s390: support command lines longer than 896 bytes

Currently s390 supports a fixed maximum command line length of 896
bytes. This isn't enough as some installers are trying to pass all
configuration

s390: support command lines longer than 896 bytes

Currently s390 supports a fixed maximum command line length of 896
bytes. This isn't enough as some installers are trying to pass all
configuration data via kernel command line, and even with zfcp alone
it is easy to generate really long command lines. Therefore extend
the command line to 4 kbytes.

In the parm area where the command line is stored there is no indication
of the maximum allowed length, so a new field which contains the maximum
length is added.

The parm area has always been initialized to zero, so with old kernels
this field would read zero. This is important because tools like zipl
could read this field. If it contains a number larger than zero zipl
knows the maximum length that can be stored in the parm area, otherwise
it must assume that it is booting a legacy kernel and only 896 bytes are
available.

The removing of trailing whitespace in head.S is also removed because
code to do this is already present in setup_boot_command_line().

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

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s390/kexec_file: move kernel image size check

In preparation of adding support for command lines with variable
sizes on s390, the check whether the new kernel image is at least HEAD_END
bytes long i

s390/kexec_file: move kernel image size check

In preparation of adding support for command lines with variable
sizes on s390, the check whether the new kernel image is at least HEAD_END
bytes long isn't correct. Move the check to kexec_file_add_components()
so we can get the size of the parm area and check the size there.

The '.org HEAD_END' directive can now also be removed from head.S. This
was used in the past to reserve space for the early sccb buffer, but with
commit 9a5131b87cac1 ("s390/boot: move sclp early buffer from fixed address
in asm to C") this is no longer required.

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

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s390/boot: initialize control registers in decompressor

Partially revert commit 4555b9f34296 ("s390/boot: move
dma sections from decompressor to decompressed kernel").
This is a prerequisite to allo

s390/boot: initialize control registers in decompressor

Partially revert commit 4555b9f34296 ("s390/boot: move
dma sections from decompressor to decompressed kernel").
This is a prerequisite to allow initialization of virtual
memory in decompressor and avoid overwriting of ASCEs in
the decompressed kernel otherwise.

Since the control registers 2, 5 and 15 are reinitialized
in the decompressed kernel again, this change does not
prevent relocating of amode31 section in any way.

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

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s390/boot: move dma sections from decompressor to decompressed kernel

This change simplifies the task of making the decompressor relocatable.

The decompressor's image contains special DMA sections

s390/boot: move dma sections from decompressor to decompressed kernel

This change simplifies the task of making the decompressor relocatable.

The decompressor's image contains special DMA sections between _sdma and
_edma. This DMA segment is loaded at boot as part of the decompressor and
then simply handed over to the decompressed kernel. The decompressor itself
never uses it in any way. The primary reason for this is the need to keep
the aforementioned DMA segment below 2GB which is required by architecture,
and because the decompressor is always loaded at a fixed low physical
address, it is guaranteed that the DMA region will not cross the 2GB
memory limit. If the DMA region had been placed in the decompressed kernel,
then KASLR would make this guarantee impossible to fulfill or it would
be restricted to the first 2GB of memory address space.

This commit moves all DMA sections between _sdma and _edma from
the decompressor's image to the decompressed kernel's image. The complete
DMA region is placed in the init section of the decompressed kernel and
immediately relocated below 2GB at start-up before it is needed by other
parts of the decompressed kernel. The relocation of the DMA region happens
even if the decompressed kernel is already located below 2GB in order
to keep the first implementation simple. The relocation should not have
any noticeable impact on boot time because the DMA segment is only a couple
of pages.

After relocating the DMA sections, the kernel has to fix all references
which point into it. In order to automate this, place all variables
pointing into the DMA sections in a special .dma.refs section. All such
variables must be defined using the new __dma_ref macro. Only variables
containing addresses within the DMA sections must be placed in the new
.dma.refs section.

Furthermore, move the initialization of control registers from
the decompressor to the decompressed kernel because some control registers
reference tables that must be placed in the DMA data section to
guarantee that their addresses are below 2G. Because the decompressed
kernel relocates the DMA sections at startup, the content of control
registers CR2, CR5 and CR15 must be updated with new addresses after
the relocation. The decompressed kernel initializes all control registers
early at boot and then updates the content of CR2, CR5 and CR15
as soon as the DMA relocation has occurred. This practically reverts
the commit a80313ff91ab ("s390/kernel: introduce .dma sections").

Signed-off-by: Alexander Egorenkov <egorenar@linux.ibm.com>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

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s390/boot: move EP_OFFSET and EP_STRING to head.S

Both macros are used only in decompressor's head.S, unnecessary to put
them in a global header used in many places like setup.h is.

Signed-off-by:

s390/boot: move EP_OFFSET and EP_STRING to head.S

Both macros are used only in decompressor's head.S, unnecessary to put
them in a global header used in many places like setup.h is.

Signed-off-by: Alexander Egorenkov <egorenar@linux.ibm.com>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

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s390/boot: move sclp early buffer from fixed address in asm to C

To make the decompressor relocatable, the early SCLP buffer with a fixed
address must be replaced with a relocatable C buffer of the

s390/boot: move sclp early buffer from fixed address in asm to C

To make the decompressor relocatable, the early SCLP buffer with a fixed
address must be replaced with a relocatable C buffer of the according size
and alignment as required by SCLP.

Introduce a new function sclp_early_set_buffer() into the SCLP driver
which enables the decompressor to change the SCLP early buffer at any time.
This will be useful when the decompressor becomes fully relocatable and
might need to change the SCLP early buffer to one with an address < 2G
as required by SCLP because it was loaded at an address >= 2G.

Signed-off-by: Alexander Egorenkov <egorenar@linux.ibm.com>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

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s390/boot: get rid of magic numbers for startup offsets

Use STARTUP_NORMAL_OFFSET and STARTUP_KDUMP_OFFSET instead of magic numbers.

Signed-off-by: Alexander Egorenkov <egorenar@linux.ibm.com>
Acke

s390/boot: get rid of magic numbers for startup offsets

Use STARTUP_NORMAL_OFFSET and STARTUP_KDUMP_OFFSET instead of magic numbers.

Signed-off-by: Alexander Egorenkov <egorenar@linux.ibm.com>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

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s390/sclp: use only one sclp early buffer to send commands

A buffer that can be used for communication with SCLP is required
to lie below 2GB memory address. Therefore, both sclp_info_sccb
and sclp_

s390/sclp: use only one sclp early buffer to send commands

A buffer that can be used for communication with SCLP is required
to lie below 2GB memory address. Therefore, both sclp_info_sccb
and sclp_early_sccb must fulfill this requirement if passed directly
to the sclp_early_cmd() function. Instead, use only sclp_early_sccb
for communication with SCLP. This allows the buffer sclp_info_sccb
to be placed anywhere in the memory address space and, therefore,
simplifies the process of making the decompressor relocatable later on,
one thing less to relocate. And make sure that the length of the new unified
early SCLP buffer is no less than the length of the removed sclp_info_sccb
buffer which might be larger than the length of the sclp_early_sccb buffer.

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

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s390/boot: make stacks part of the decompressor's image

Instead of using constant addresses for the normal and dump-info stacks,
allocate both stacks in the decompressor's image and load the stack r

s390/boot: make stacks part of the decompressor's image

Instead of using constant addresses for the normal and dump-info stacks,
allocate both stacks in the decompressor's image and load the stack register
in a position-independent manner.

This will allow loading and entering the decompressor at an arbitrary
memory address without corrupting the content at the fixed addresses
used until now for both stacks. This is one of the prerequisites
for being able to kexec the decompressor from its load address without
relocating it first.

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

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s390/ipl: make parameter area accessible via struct parmarea

Since commit 9a965ea95135 ("s390/kexec_file: Simplify parmarea
access") we have struct parmarea which describes the layout of the
kernel

s390/ipl: make parameter area accessible via struct parmarea

Since commit 9a965ea95135 ("s390/kexec_file: Simplify parmarea
access") we have struct parmarea which describes the layout of the
kernel parameter area.

Make the kernel parameter area available as global variable parmarea
of type struct parmarea, which allows to easily access its members.

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

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s390/decompressor: add stacktrace support

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

Linux version 5.10.0-rc

s390/decompressor: add stacktrace support

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

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s390/decompressor: correct some asm symbols annotations

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

Also currently the most part of startup is m

s390/decompressor: correct some asm symbols annotations

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

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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

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>

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s390/startup: avoid save_area_sync overflow

Currently we overflow save_area_sync and write over
save_area_async. Although this is not a real problem make
startup_pgm_check_handler consistent with la

s390/startup: avoid save_area_sync overflow

Currently we overflow save_area_sync and write over
save_area_async. Although this is not a real problem make
startup_pgm_check_handler consistent with late pgm check handler and
store [%r0,%r7] directly into gpregs_save_area.

Reviewed-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

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s390/boot: avoid unnecessary zeroing of .bss section

.bss section is a part of the decompressor's image now, linker fills it
with zeros already. No need do it with memset additionally.

Reviewed-by:

s390/boot: avoid unnecessary zeroing of .bss section

.bss section is a part of the decompressor's image now, linker fills it
with zeros already. No need do it with memset additionally.

Reviewed-by: Alexander Egorenkov <egorenar@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

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