summaryrefslogtreecommitdiff
path: root/arch/s390/boot/head.S
AgeCommit message (Collapse)AuthorFilesLines
2023-07-03s390: fix various typosHeiko Carstens1-1/+1
Fix various typos found with codespell. Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
2023-06-28s390: consistently use .balign instead of .alignHeiko Carstens1-7/+7
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>
2022-05-18s390/head: get rid of 31 bit leftoversHeiko Carstens1-149/+126
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>
2022-05-17s390/boot: workaround llvm IAS bugHeiko Carstens1-13/+21
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>
2022-05-06s390/boot: convert parmarea to CHeiko Carstens1-20/+0
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>
2022-05-06s390/boot: convert initial lowcore to CHeiko Carstens1-54/+8
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>
2022-05-06s390/head: initialize all new pswsHeiko Carstens1-7/+15
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>
2022-05-06s390/boot: change initial program check handler to disabled wait pswHeiko Carstens1-1/+1
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>
2022-05-06s390/head: adjust iplstart entry pointHeiko Carstens1-5/+8
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>
2022-02-07s390: remove invalid email address of Heiko CarstensHeiko Carstens1-1/+0
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>
2021-10-26s390: support command lines longer than 896 bytesSven Schnelle1-23/+12
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>
2021-10-26s390/kexec_file: move kernel image size checkSven Schnelle1-2/+0
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>
2021-10-04s390/boot: initialize control registers in decompressorAlexander Gordeev1-0/+17
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>
2021-07-27s390/boot: move dma sections from decompressor to decompressed kernelAlexander Egorenkov1-30/+0
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>
2021-07-27s390/boot: move EP_OFFSET and EP_STRING to head.SAlexander Egorenkov1-0/+3
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>
2021-07-27s390/boot: move sclp early buffer from fixed address in asm to CAlexander Egorenkov1-3/+1
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>
2021-07-27s390/boot: get rid of magic numbers for startup offsetsAlexander Egorenkov1-4/+4
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>
2021-07-27s390/sclp: use only one sclp early buffer to send commandsAlexander Egorenkov1-1/+2
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>
2021-07-27s390/boot: make stacks part of the decompressor's imageAlexander Egorenkov1-8/+2
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>
2021-06-07s390/ipl: make parameter area accessible via struct parmareaHeiko Carstens1-0/+3
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>
2020-11-20s390/decompressor: add stacktrace supportVasily Gorbik1-1/+2
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>
2020-11-20s390/decompressor: correct some asm symbols annotationsVasily Gorbik1-7/+8
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>
2020-11-09s390/head: set io/ext handlers to disabled waitVasily Gorbik1-1/+13
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>
2020-09-29s390/startup: avoid save_area_sync overflowVasily Gorbik1-10/+11
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>
2020-09-21s390/boot: avoid unnecessary zeroing of .bss sectionVasily Gorbik1-6/+0
.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>
2020-09-16s390/boot: enable .bss section for compressed kernelAlexander Egorenkov1-0/+6
- Support static uninitialized variables in compressed kernel. - Remove chkbss script - Get rid of workarounds for not having .bss section Signed-off-by: Alexander Egorenkov <egorenar@linux.ibm.com> Reviewed-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2020-01-22s390: fix __EMIT_BUG() macroSven Schnelle1-1/+1
Setting a kprobe on getname_flags() failed: $ echo 'p:tmr1 getname_flags +0(%r2):ustring' > kprobe_events -bash: echo: write error: Invalid argument Debugging the kprobes code showed that the address of getname_flags() is contained in the __bug_table. Kprobes doesn't allow to set probes at BUG() locations. $ objdump -j __bug_table -x build/fs/namei.o [..] 0000000000000108 R_390_PC32 .text+0x00000000000075a8 000000000000010c R_390_PC32 .L223+0x0000000000000004 I was expecting getname_flags() to start with a BUG(), but: 7598: e3 20 10 00 00 04 lg %r2,0(%r1) 759e: c0 f4 00 00 00 00 jg 759e <putname+0x7e> 75a0: R_390_PLT32DBL kmem_cache_free+0x2 75a4: a7 f4 00 01 j 75a6 <putname+0x86> 00000000000075a8 <getname_flags>: 75a8: c0 04 00 00 00 00 brcl 0,75a8 <getname_flags> 75ae: eb 6f f0 48 00 24 stmg %r6,%r15,72(%r15) 75b4: b9 04 00 ef lgr %r14,%r15 75b8: e3 f0 ff a8 ff 71 lay %r15,-88(%r15) So the BUG() is actually the last opcode of the previous function. Fix this by switching to using the MONITOR CALL (MC) instruction, and set the entry in __bug_table to the beginning of that MC. Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2019-09-13s390/startup: add pgm check info printingVasily Gorbik1-1/+9
Try to print out startup pgm check info including exact linux kernel version, pgm interruption code and ilc, psw and general registers. Like the following: Linux version 5.3.0-rc7-07282-ge7b4d41d61bd-dirty (gor@tuxmaker) #3 SMP PREEMPT Thu Sep 5 16:07:34 CEST 2019 Kernel fault: interruption code 0005 ilc:2 PSW : 0000000180000000 0000000000012e52 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 0000000000019a58 000000000000bf68 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 000000000001a041 0000000000000000 0000000004c9c000 0000000000010070 0000000000012e42 000000000000beb0 This info makes it apparent that kernel startup failed and might help to understand what went wrong without actual standalone dump. Printing code runs on its own stack of 1 page (at unused 0x5000), which should be sufficient for sclp_early_printk usage (typical stack usage observed has been around 512 bytes). The code has pgm check recursion prevention, despite pgm check info printing failure (follow on pgm check) or success it restores original faulty psw and gprs and does disabled wait. Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
2019-08-21s390/startup: add initial pgm check handlerVasily Gorbik1-1/+23
The startup code is getting more complicated with features like kaslr and secure boot in place. In a potential unexpected startup code crash case the system would end up in a pgm check loop at address 0, overwriting pgm check old psw value and just making debugging more complicated. To avoid that introduce startup program check handler which is active immediately after kernel start and until early_pgm_check_handler is set in kernel/early.c. So it covers kernel relocation phase and transition to it. This pgm check handler simply saves general/control registers and psw in the save area which should guarantee that we still have something to look at when standalone dumper is called without saving registers. And it does disabled wait with a faulty address in the end. Acked-by: Ilya Leoshkevich <iii@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2019-07-23s390: enable detection of kernel version from bzImageVasily Gorbik1-0/+1
Extend "parmarea" to include an offset of the version string, which is stored as 8-byte big endian value. To retrieve version string from bzImage reliably, one should check the presence of "S390EP" ascii string at 0x10008 (available since v3.2), then read the version string offset from 0x10428 (which has been 0 since v3.2 up to now). The string is null terminated. Could be retrieved with the following "file" command magic (requires file v5.34): 8 string \x02\x00\x00\x18\x60\x00\x00\x50\x02\x00\x00\x68\x60\x00\x00\x50\x40\x40\x40\x40\x40\x40\x40\x40 Linux S390 >0x10008 string S390EP >>0x10428 bequad >0 >>>(0x10428.Q) string >\0 \b, version %s Reported-by: Petr Tesarik <ptesarik@suse.com> Suggested-by: Petr Tesarik <ptesarik@suse.com> Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
2019-04-29s390/kernel: introduce .dma sectionsGerald Schaefer1-1/+31
With a relocatable kernel that could reside at any place in memory, code and data that has to stay below 2 GB needs special handling. This patch introduces .dma sections for such text, data and ex_table. The sections will be part of the decompressor kernel, so they will not be relocated and stay below 2 GB. Their location is passed over to the decompressed / relocated kernel via the .boot.preserved.data section. The duald and aste for control register setup also need to stay below 2 GB, so move the setup code from arch/s390/kernel/head64.S to arch/s390/boot/head.S. The duct and linkage_stack could reside above 2 GB, but their content has to be preserved for the decompresed kernel, so they are also moved into the .dma section. The start and end address of the .dma sections is added to vmcoreinfo, for crash support, to help debugging in case the kernel crashed there. Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com> Reviewed-by: Philipp Rudo <prudo@linux.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2019-04-29s390/sclp: do not use static sccbsGerald Schaefer1-1/+4
The sccbs for init/read/sdias/early have to be located below 2 GB, and they are currently defined as a static buffer. With a relocatable kernel that could reside at any place in memory, this will no longer guarantee the location below 2 GB, so use a dynamic GFP_DMA allocation instead. The sclp_early_sccb buffer needs special handling, as it can be used very early, and by both the decompressor and also the decompressed kernel. Therefore, a fixed 4 KB buffer is introduced at 0x11000, the former PARMAREA_END. The new PARMAREA_END is now 0x12000, and it is renamed to HEAD_END, as it is rather the end of head.S and not the end of the parmarea. Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com> Reviewed-by: Philipp Rudo <prudo@linux.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2019-04-29s390/kexec_file: Simplify parmarea accessPhilipp Rudo1-5/+6
Access the parmarea in head.S via a struct instead of individual offsets. While at it make the fields in the parmarea .quads. Signed-off-by: Philipp Rudo <prudo@linux.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2018-10-09s390/head: avoid doubling early boot stack size under KASANVasily Gorbik1-1/+1
Early boot stack uses predefined 4 pages of memory 0x8000-0xC000. This stack is used to run not instumented decompressor/facilities verification C code. It doesn't make sense to double its size when the kernel is built with KASAN support. BOOT_STACK_ORDER is introduced to avoid that. Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2018-10-09s390: remove decompressor's head.SVasily Gorbik1-5/+1
Decompressor's head.S provided "data mover" sole purpose of which has been to safely move uncompressed kernel at 0x100000 and jump to it. With current bzImage layout entire decompressor's code guaranteed to be in a safe location under 0x100000, and hence could not be overwritten during kernel move. For that reason head.S could be replaced with simple memmove function. To do so introduce early boot code phase which is executed from arch/s390/boot/head.S after "verify_facilities" and takes care of optional kernel image decompression and transition to it. Reviewed-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2018-09-20s390: clean up stacks setupVasily Gorbik1-2/+1
Replace hard coded stack frame overhead values with STACK_FRAME_OVERHEAD definition. Avoid unnecessary arithmetic instructions. Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2018-09-20s390: add initial 64-bit restart PSWMartin Schwidefsky1-0/+3
To be able to start a kernel image loaded into memory with a PSW restart, place a 64-bit restart PSW at 0x1a0 in absolute lowcore. Suggested-by: Dominik Klein <dominik.klein@linux.ibm.com> Tested-by: Dominik Klein <dominik.klein@linux.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2018-07-02s390/boot: block uncompressed vmlinux booting attemptsVasily Gorbik1-2/+2
Since the plain vmlinux ELF file no longer carries all necessary parts for starting up (like the entry point and decompressor), add a check which would block boot process and encourage users to use bzImage or arch/s390/boot/compressed/vmlinux instead. The check relies on s390 linux entry point ABI definition, which is only present in bzImage and arch/s390/boot/compressed/vmlinux. Reported-by: Guenter Roeck <linux@roeck-us.net> Tested-by: Guenter Roeck <linux@roeck-us.net> Acked-by: Cornelia Huck <cohuck@redhat.com> Acked-by: Christian Borntraeger <borntraeger@de.ibm.com> Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2018-06-25s390/decompressor: support uncompressed kernelVasily Gorbik1-0/+4
Implement uncompressed kernel support (when "None" is picked in kernel compression mode list). In that case an actual decompression code is skipped and control is passed from boot/head.S to startup_continue in kernel/head64.S. To achieve that uncompressed kernel payload is conditionally put at 0x100000 in bzImage. In reality this is very close to classic uncompressed kernel "image", but the decompressor has its own build and link process, kernel/head64.S lives at 0x100000 rather than at 0x11000, and .bss section is reused for both stages. Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2018-06-25s390/decompressor: rename entry point to startup_decompressorVasily Gorbik1-4/+1
Rename the decompressor entry point to startup_decompressor to avoid confusion, leaving startup_continue as the entry point of the uncompressed image. Also remove obsolete comment, as the decompressor code is unconditionally called from boot/head.S now. Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2018-06-25s390/boot: make head.S and als.c be part of the decompressor onlyVasily Gorbik1-0/+339
Since uncompressed kernel image does not have to be bootable anymore, move head.S, head_kdump.S and als.c to boot/ folder and compile them in just in the decompressor. Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>