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2024-09-07s390/boot: Move boot_printk() code to own fileHeiko Carstens1-1/+2
Keep the printk code separate from the program check code and move boot_printk() and helper functions to own printk.c file. Reviewed-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2024-09-07s390/boot: Compile all files with the same march flagHeiko Carstens1-14/+5
Only a couple of files of the decompressor are compiled with the minimum architecture level. This is problematic for potential function calls between compile units, especially if a target function is within a compile until compiled for a higher architecture level, since that may lead to an unexpected operation exception. Therefore compile all files of the decompressor for the same (minimum) architecture level. Reviewed-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2024-09-07s390/boot: Increase minimum architecture to z10Heiko Carstens1-4/+0
The decompressor code is partially compiled with march=z900 so it is possible to print an error message in case a kernel is booted on a machine which misses facilities to execute the kernel. Given that the decompressor code also includes header files from the core kernel this causes problems for inline assemblies and other code where the minimum assumed architecture level is set to z10 in the meantime. If such code is also used in the decompressor (e.g. inline functions) z900 support must be implemented again. In order to avoid this and to keep things simple just raise the minimum architecture level to z10 for the decompressor just like for the kernel. Reviewed-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2024-08-27s390/build: Avoid relocation information in final vmlinuxJens Remus1-5/+3
Since commit 778666df60f0 ("s390: compile relocatable kernel without -fPIE") the kernel vmlinux ELF file is linked with --emit-relocs to preserve all relocations, so that all absolute relocations can be extracted using the 'relocs' tool to adjust them during boot. Port and adapt Petr Pavlu's x86 commit 9d9173e9ceb6 ("x86/build: Avoid relocation information in final vmlinux") to s390 to strip all relocations from the final vmlinux ELF file to optimize its size. Following is his original commit message with minor adaptions for s390: The Linux build process on s390 roughly consists of compiling all input files, statically linking them into a vmlinux ELF file, and then taking and turning this file into an actual bzImage bootable file. vmlinux has in this process two main purposes: 1) It is an intermediate build target on the way to produce the final bootable image. 2) It is a file that is expected to be used by debuggers and standard ELF tooling to work with the built kernel. For the second purpose, a vmlinux file is typically collected by various package build recipes, such as distribution spec files, including the kernel's own tar-pkg target. When building the kernel vmlinux contains also relocation information produced by using the --emit-relocs linker option. This is utilized by subsequent build steps to create relocs.S and produce a relocatable image. However, the information is not needed by debuggers and other standard ELF tooling. The issue is then that the collected vmlinux file and hence distribution packages end up unnecessarily large because of this extra data. The following is a size comparison of vmlinux v6.10 with and without the relocation information: | Configuration | With relocs | Stripped relocs | | defconfig | 696 MB | 320 MB | | -CONFIG_DEBUG_INFO | 48 MB | 32 MB | Optimize a resulting vmlinux by adding a postlink step that splits the relocation information into relocs.S and then strips it from the vmlinux binary. Reviewed-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Jens Remus <jremus@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-07-23s390: Remove protvirt and kvm config guards for uv codeJanosch Frank1-2/+1
Removing the CONFIG_PROTECTED_VIRTUALIZATION_GUEST ifdefs and config option as well as CONFIG_KVM ifdefs in uv files. Having this configurable has been more of a pain than a help. It's time to remove the ifdefs and the config option. Signed-off-by: Janosch Frank <frankja@linux.ibm.com> Acked-by: Christian Borntraeger <borntraeger@linux.ibm.com> Acked-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-07-23s390/alternatives: Allow early alternative patching in decompressorSven Schnelle1-1/+1
Add the required code to patch alternatives early in the decompressor. This is required for the upcoming lowcore relocation changes, where alternatives for facility 193 need to get patched before lowcore alternatives. Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com> Co-developed-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-07-04s390/boot: add the KMSAN runtime stubIlya Leoshkevich1-0/+1
It should be possible to have inline functions in the s390 header files, which call kmsan_unpoison_memory(). The problem is that these header files might be included by the decompressor, which does not contain KMSAN runtime, causing linker errors. Not compiling these calls if __SANITIZE_MEMORY__ is not defined - either by changing kmsan-checks.h or at the call sites - may cause unintended side effects, since calling these functions from an uninstrumented code that is linked into the kernel is valid use case. One might want to explicitly distinguish between the kernel and the decompressor. Checking for a decompressor-specific #define is quite heavy-handed, and will have to be done at all call sites. A more generic approach is to provide a dummy kmsan_unpoison_memory() definition. This produces some runtime overhead, but only when building with CONFIG_KMSAN. The benefit is that it does not disturb the existing KMSAN build logic and call sites don't need to be changed. Link: https://lkml.kernel.org/r/20240621113706.315500-25-iii@linux.ibm.com Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> Reviewed-by: Alexander Potapenko <glider@google.com> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: <kasan-dev@googlegroups.com> Cc: Marco Elver <elver@google.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Masami Hiramatsu (Google) <mhiramat@kernel.org> Cc: Pekka Enberg <penberg@kernel.org> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Steven Rostedt (Google) <rostedt@goodmis.org> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-04s390/boot: turn off KMSANIlya Leoshkevich1-0/+2
All other sanitizers are disabled for boot as well. While at it, add a comment explaining why we need this. Link: https://lkml.kernel.org/r/20240621113706.315500-23-iii@linux.ibm.com Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com> Reviewed-by: Alexander Potapenko <glider@google.com> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: <kasan-dev@googlegroups.com> Cc: Marco Elver <elver@google.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Masami Hiramatsu (Google) <mhiramat@kernel.org> Cc: Pekka Enberg <penberg@kernel.org> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Steven Rostedt (Google) <rostedt@goodmis.org> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-04-29s390: Compile kernel with -fPIC and link with -no-pieSumanth Korikkar1-6/+1
When the kernel is built with CONFIG_PIE_BUILD option enabled it uses dynamic symbols, for which the linker does not allow more than 64K number of entries. This can break features like kpatch. Hence, whenever possible the kernel is built with CONFIG_PIE_BUILD option disabled. For that support of unaligned symbols generated by linker scripts in the compiler is necessary. However, older compilers might lack such support. In that case the build process resorts to CONFIG_PIE_BUILD option-enabled build. Compile object files with -fPIC option and then link the kernel binary with -no-pie linker option. As result, the dynamic symbols are not generated and not only kpatch feature succeeds, but also the whole CONFIG_PIE_BUILD option-enabled code could be dropped. [ agordeev: Reworded the commit message ] Suggested-by: Ulrich Weigand <ulrich.weigand@de.ibm.com> Signed-off-by: Sumanth Korikkar <sumanthk@linux.ibm.com> Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com> Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
2024-04-09s390: adjust indentation of RELOCS command build step outHeiko Carstens1-1/+1
Common pattern in non-verbose build output for quiet commands is that the shorthand of a command including whitespace contains at least eight characters. Adjust this for the RELOCS command, which comes only with seven characters. Before: SORTTAB vmlinux CC arch/s390/boot/version.o RELOCS arch/s390/boot/relocs.S OBJCOPY arch/s390/boot/info.bin After: SORTTAB vmlinux CC arch/s390/boot/version.o RELOCS arch/s390/boot/relocs.S OBJCOPY arch/s390/boot/info.bin Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
2024-02-22s390/boot: workaround current 'llvm-objdump -t -j ...' behaviorNathan Chancellor1-2/+2
When building with OBJDUMP=llvm-objdump, there are a series of warnings from the section comparisons that arch/s390/boot/Makefile performs between vmlinux and arch/s390/boot/vmlinux: llvm-objdump: warning: section '.boot.preserved.data' mentioned in a -j/--section option, but not found in any input file llvm-objdump: warning: section '.boot.data' mentioned in a -j/--section option, but not found in any input file llvm-objdump: warning: section '.boot.preserved.data' mentioned in a -j/--section option, but not found in any input file llvm-objdump: warning: section '.boot.data' mentioned in a -j/--section option, but not found in any input file The warning is a little misleading, as these sections do exist in the input files. It is really pointing out that llvm-objdump does not match GNU objdump's behavior of respecting '-j' / '--section' in combination with '-t' / '--syms': $ s390x-linux-gnu-objdump -t -j .boot.data vmlinux.full vmlinux.full: file format elf64-s390 SYMBOL TABLE: 0000000001951000 l O .boot.data 0000000000003000 sclp_info_sccb 00000000019550e0 l O .boot.data 0000000000000001 sclp_info_sccb_valid 00000000019550e2 g O .boot.data 0000000000001000 early_command_line ... $ llvm-objdump -t -j .boot.data vmlinux.full vmlinux.full: file format elf64-s390 SYMBOL TABLE: 0000000000100040 l O .text 0000000000000010 dw_psw 0000000000000000 l df *ABS* 0000000000000000 main.c 00000000001001b0 l F .text 00000000000000c6 trace_event_raw_event_initcall_level 0000000000100280 l F .text 0000000000000100 perf_trace_initcall_level ... It may be possible to change llvm-objdump's behavior to match GNU objdump's behavior but the difficulty of that task has not yet been explored. The combination of '$(OBJDUMP) -t -j' is not common in the kernel tree on a whole, so workaround this tool difference by grepping for the sections in the full symbol table output in a similar manner to the sed invocation. This results in no visible change for GNU objdump users while fixing the warnings for OBJDUMP=llvm-objdump, further enabling use of LLVM=1 for ARCH=s390 with versions of LLVM that have support for s390 in ld.lld and llvm-objcopy. Reported-by: Heiko Carstens <hca@linux.ibm.com> Closes: https://lore.kernel.org/20240219113248.16287-C-hca@linux.ibm.com/ Link: https://github.com/ClangBuiltLinux/linux/issues/859 Signed-off-by: Nathan Chancellor <nathan@kernel.org> Link: https://lore.kernel.org/r/20240220-s390-work-around-llvm-objdump-t-j-v1-1-47bb0366a831@kernel.org Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2024-02-20s390: compile relocatable kernel without -fPIEJosh Poimboeuf1-1/+13
On s390, currently kernel uses the '-fPIE' compiler flag for compiling vmlinux. This has a few problems: - It uses dynamic symbols (.dynsym), for which the linker refuses to allow more than 64k sections. This can break features which use '-ffunction-sections' and '-fdata-sections', including kpatch-build [1] and Function Granular KASLR. - It unnecessarily uses GOT relocations, adding an extra layer of indirection for many memory accesses. Instead of using '-fPIE', resolve all the relocations at link time and then manually adjust any absolute relocations (R_390_64) during boot. This is done by first telling the linker to preserve all relocations during the vmlinux link. (Note this is harmless: they are later stripped in the vmlinux.bin link.) Then use the 'relocs' tool to find all absolute relocations (R_390_64) which apply to allocatable sections. The offsets of those relocations are saved in a special section which is then used to adjust the relocations during boot. (Note: For some reason, Clang occasionally creates a GOT reference, even without '-fPIE'. So Clang-compiled kernels have a GOT, which needs to be adjusted.) On my mostly-defconfig kernel, this reduces kernel text size by ~1.3%. [1] https://github.com/dynup/kpatch/issues/1284 [2] https://gcc.gnu.org/pipermail/gcc-patches/2023-June/622872.html [3] https://gcc.gnu.org/pipermail/gcc-patches/2023-August/625986.html Compiler consideration: Gcc recently implemented an optimization [2] for loading symbols without explicit alignment, aligning with the IBM Z ELF ABI. This ABI mandates symbols to reside on a 2-byte boundary, enabling the use of the larl instruction. However, kernel linker scripts may still generate unaligned symbols. To address this, a new -munaligned-symbols option has been introduced [3] in recent gcc versions. This option has to be used with future gcc versions. Older Clang lacks support for handling unaligned symbols generated by kernel linker scripts when the kernel is built without -fPIE. However, future versions of Clang will include support for the -munaligned-symbols option. When the support is unavailable, compile the kernel with -fPIE to maintain the existing behavior. In addition to it: move vmlinux.relocs to safe relocation When the kernel is built with CONFIG_KERNEL_UNCOMPRESSED, the entire uncompressed vmlinux.bin is positioned in the bzImage decompressor image at the default kernel LMA of 0x100000, enabling it to be executed in-place. However, the size of .vmlinux.relocs could be large enough to cause an overlap with the uncompressed kernel at the address 0x100000. To address this issue, .vmlinux.relocs is positioned after the .rodata.compressed in the bzImage. Nevertheless, in this configuration, vmlinux.relocs will overlap with the .bss section of vmlinux.bin. To overcome that, move vmlinux.relocs to a safe location before clearing .bss and handling relocs. Compile warning fix from Sumanth Korikkar: When kernel is built with CONFIG_LD_ORPHAN_WARN and -fno-PIE, there are several warnings: ld: warning: orphan section `.rela.iplt' from `arch/s390/kernel/head64.o' being placed in section `.rela.dyn' ld: warning: orphan section `.rela.head.text' from `arch/s390/kernel/head64.o' being placed in section `.rela.dyn' ld: warning: orphan section `.rela.init.text' from `arch/s390/kernel/head64.o' being placed in section `.rela.dyn' ld: warning: orphan section `.rela.rodata.cst8' from `arch/s390/kernel/head64.o' being placed in section `.rela.dyn' Orphan sections are sections that exist in an object file but don't have a corresponding output section in the final executable. ld raises a warning when it identifies such sections. Eliminate the warning by placing all .rela orphan sections in .rela.dyn and raise an error when size of .rela.dyn is greater than zero. i.e. Dont just neglect orphan sections. This is similar to adjustment performed in x86, where kernel is built with -fno-PIE. commit 5354e84598f2 ("x86/build: Add asserts for unwanted sections") [sumanthk@linux.ibm.com: rebased Josh Poimboeuf patches and move vmlinux.relocs to safe location] [hca@linux.ibm.com: merged compile warning fix from Sumanth] Tested-by: Sumanth Korikkar <sumanthk@linux.ibm.com> Acked-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Sumanth Korikkar <sumanthk@linux.ibm.com> Link: https://lore.kernel.org/r/20240219132734.22881-4-sumanthk@linux.ibm.com Link: https://lore.kernel.org/r/20240219132734.22881-5-sumanthk@linux.ibm.com Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2024-02-20s390/boot: add 'alloc' to info.bin .vmlinux.info section flagsNathan Chancellor1-1/+1
When attempting to boot a kernel compiled with OBJCOPY=llvm-objcopy, there is a crash right at boot: Out of memory allocating 6d7800 bytes 8 aligned in range 0:20000000 Reserved memory ranges: 0000000000000000 a394c3c30d90cdaf DECOMPRESSOR Usable online memory ranges (info source: sclp read info [3]): 0000000000000000 0000000020000000 Usable online memory total: 20000000 Reserved: a394c3c30d90cdaf Free: 0 Call Trace: (sp:0000000000033e90 [<0000000000012fbc>] physmem_alloc_top_down+0x5c/0x104) sp:0000000000033f00 [<0000000000011d56>] startup_kernel+0x3a6/0x77c sp:0000000000033f60 [<00000000000100f4>] startup_normal+0xd4/0xd4 GNU objcopy does not have any issues. Looking at differences between the object files in each build reveals info.bin does not get properly populated with llvm-objcopy, which results in an empty .vmlinux.info section. $ file {gnu,llvm}-objcopy/arch/s390/boot/info.bin gnu-objcopy/arch/s390/boot/info.bin: data llvm-objcopy/arch/s390/boot/info.bin: empty $ llvm-readelf --section-headers {gnu,llvm}-objcopy/arch/s390/boot/vmlinux | rg 'File:|\.vmlinux\.info|\.decompressor\.syms' File: gnu-objcopy/arch/s390/boot/vmlinux [12] .vmlinux.info PROGBITS 0000000000034000 035000 000078 00 WA 0 0 1 [13] .decompressor.syms PROGBITS 0000000000034078 035078 000b00 00 WA 0 0 1 File: llvm-objcopy/arch/s390/boot/vmlinux [12] .vmlinux.info PROGBITS 0000000000034000 035000 000000 00 WA 0 0 1 [13] .decompressor.syms PROGBITS 0000000000034000 035000 000b00 00 WA 0 0 1 Ulrich points out that llvm-objcopy only copies sections marked as alloc with a binary output target, whereas the .vmlinux.info section is only marked as load. Add 'alloc' in addition to 'load', so that both objcopy implementations work properly: $ file {gnu,llvm}-objcopy/arch/s390/boot/info.bin gnu-objcopy/arch/s390/boot/info.bin: data llvm-objcopy/arch/s390/boot/info.bin: data $ llvm-readelf --section-headers {gnu,llvm}-objcopy/arch/s390/boot/vmlinux | rg 'File:|\.vmlinux\.info|\.decompressor\.syms' File: gnu-objcopy/arch/s390/boot/vmlinux [12] .vmlinux.info PROGBITS 0000000000034000 035000 000078 00 WA 0 0 1 [13] .decompressor.syms PROGBITS 0000000000034078 035078 000b00 00 WA 0 0 1 File: llvm-objcopy/arch/s390/boot/vmlinux [12] .vmlinux.info PROGBITS 0000000000034000 035000 000078 00 WA 0 0 1 [13] .decompressor.syms PROGBITS 0000000000034078 035078 000b00 00 WA 0 0 1 Closes: https://github.com/ClangBuiltLinux/linux/issues/1996 Link: https://github.com/llvm/llvm-project/commit/3c02cb7492fc78fb678264cebf57ff88e478e14f Suggested-by: Ulrich Weigand <ulrich.weigand@de.ibm.com> Signed-off-by: Nathan Chancellor <nathan@kernel.org> Link: https://lore.kernel.org/r/20240216-s390-fix-boot-with-llvm-objcopy-v1-1-0ac623daf42b@kernel.org Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2024-02-14s390/boot: add support for CONFIG_LD_ORPHAN_WARNNathan Chancellor1-2/+3
arch/s390/boot/vmlinux uses a different linker script and build rules than the main vmlinux, so the '--orphan-handling' flag is not applied to it. Add support for '--orphan-handling' so that all sections are properly described in the linker script, which helps eliminate bugs between linker implementations having different orphan section heuristics. Signed-off-by: Nathan Chancellor <nathan@kernel.org> Tested-by: Justin Stitt <justinstitt@google.com> Link: https://lore.kernel.org/r/20240207-s390-lld-and-orphan-warn-v1-1-8a665b3346ab@kernel.org Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2023-03-20s390/boot: rename mem_detect to physmem_infoVasily Gorbik1-1/+1
In preparation to extending mem_detect with additional information like reserved ranges rename it to more generic physmem_info. This new naming also help to avoid confusion by using more exact terms like "physmem online ranges", etc. Acked-by: Heiko Carstens <hca@linux.ibm.com> Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2023-02-28s390/decompressor: add link map savingVasily Gorbik1-1/+3
Produce arch/s390/boot/vmlinux.map link map for the decompressor, when CONFIG_VMLINUX_MAP option is enabled. Link map is quite useful during making kernel changes related to how the decompressor is composed and debugging linker scripts. Acked-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>
2023-01-13s390/mm: start kernel with DAT enabledAlexander Gordeev1-1/+1
The setup of the kernel virtual address space is spread throughout the sources, boot stages and config options like this: 1. The available physical memory regions are queried and stored as mem_detect information for later use in the decompressor. 2. Based on the physical memory availability the virtual memory layout is established in the decompressor; 3. If CONFIG_KASAN is disabled the kernel paging setup code populates kernel pgtables and turns DAT mode on. It uses the information stored at step [1]. 4. If CONFIG_KASAN is enabled the kernel early boot kasan setup populates kernel pgtables and turns DAT mode on. It uses the information stored at step [1]. The kasan setup creates early_pg_dir directory and directly overwrites swapper_pg_dir entries to make shadow memory pages available. Move the kernel virtual memory setup to the decompressor and start the kernel with DAT turned on right from the very first istruction. That completely eliminates the boot phase when the kernel runs in DAT-off mode, simplies the overall design and consolidates pgtables setup. The identity mapping is created in the decompressor, while kasan shadow mappings are still created by the early boot kernel code. Share with decompressor the existing kasan memory allocator. It decreases the size of a newly requested memory block from pgalloc_pos and ensures that kernel image is not overwritten. pgalloc_low and pgalloc_pos pointers are made preserved boot variables for that. Use the bootdata infrastructure to setup swapper_pg_dir and invalid_pg_dir directories used by the kernel later. The interim early_pg_dir directory established by the kasan initialization code gets eliminated as result. As the kernel runs in DAT-on mode only the PSW_KERNEL_BITS define gets PSW_MASK_DAT bit by default. Additionally, the setup_lowcore_dat_off() and setup_lowcore_dat_on() routines get merged, since there is no DAT-off mode stage anymore. The memory mappings are created with RW+X protection that allows the early boot code setting up all necessary data and services for the kernel being booted. Just before the paging is enabled the memory protection is changed to RO+X for text, RO+NX for read-only data and RW+NX for kernel data and the identity mapping. Reviewed-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2022-11-08s390: always build relocatable kernelHeiko Carstens1-2/+1
Nathan Chancellor reported several link errors on s390 with CONFIG_RELOCATABLE disabled, after binutils commit 906f69cf65da ("IBM zSystems: Issue error for *DBL relocs on misaligned symbols"). The binutils commit reveals potential miscompiles that might have happened already before with linker script defined symbols at odd addresses. A similar bug was recently fixed in the kernel with commit c9305b6c1f52 ("s390: fix nospec table alignments"). See https://github.com/ClangBuiltLinux/linux/issues/1747 for an analysis from Ulich Weigand. Therefore always build a relocatable kernel to avoid this problem. There is hardly any use-case for non-relocatable kernels, so this shouldn't be controversial. Link: https://github.com/ClangBuiltLinux/linux/issues/1747 Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Reported-by: Nathan Chancellor <nathan@kernel.org> Tested-by: Nathan Chancellor <nathan@kernel.org> Link: https://lore.kernel.org/r/20221030182202.2062705-1-hca@linux.ibm.com Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
2022-05-06s390/boot: convert initial lowcore to CHeiko Carstens1-1/+1
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/boot: get rid of startup archiveHeiko Carstens1-8/+68
The final kernel image is created by linking decompressor object files with a startup archive. The startup archive file however does not contain only optional code and data which can be discarded if not referenced. It also contains mandatory object data like head.o which must never be discarded, even if not referenced. Move the decompresser code and linker script to the boot directory and get rid of the startup archive so everything is kept during link time. Acked-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-07-30s390: move the install rule to arch/s390/MakefileMasahiro Yamada1-4/+0
Currently, the install target in arch/s390/Makefile descends into arch/s390/boot/Makefile to invoke the shell script, but there is no good reason to do so. arch/s390/Makefile can run the shell script directly. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Link: https://lore.kernel.org/r/20210729142338.446002-1-masahiroy@kernel.org Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-07-30s390: enable KCSANIlya Leoshkevich1-0/+1
s390x GCC and SystemZ Clang have ThreadSanitizer support now [1] [2], so enable KCSAN for s390. [1] https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=ea22954e7c58 [2] https://reviews.llvm.org/D105629 Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-07-27s390/boot: move dma sections from decompressor to decompressed kernelAlexander Egorenkov1-1/+1
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>
2020-09-16s390/boot: enable .bss section for compressed kernelAlexander Egorenkov1-4/+0
- 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>
2020-03-31Merge tag 'kvmarm-5.7' of ↵Paolo Bonzini1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD KVM/arm updates for Linux 5.7 - GICv4.1 support - 32bit host removal
2020-02-27s390/protvirt: introduce host side setupVasily Gorbik1-1/+1
Add "prot_virt" command line option which controls if the kernel protected VMs support is enabled at early boot time. This has to be done early, because it needs large amounts of memory and will disable some features like STP time sync for the lpar. Extend ultravisor info definitions and expose it via uv_info struct filled in during startup. Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Reviewed-by: Thomas Huth <thuth@redhat.com> Acked-by: David Hildenbrand <david@redhat.com> Reviewed-by: Cornelia Huck <cohuck@redhat.com> Acked-by: Christian Borntraeger <borntraeger@de.ibm.com> [borntraeger@de.ibm.com: patch merging, splitting, fixing] Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2020-02-17s390: make 'install' not depend on vmlinuxMasahiro Yamada1-1/+1
For the same reason as commit 19514fc665ff ("arm, kbuild: make "make install" not depend on vmlinux"), the install targets should never trigger the rebuild of the kernel. The variable, CONFIGURE, is not set by anyone. Remove it as well. Link: https://lkml.kernel.org/r/20200216144829.27023-1-masahiroy@kernel.org Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2019-09-13s390/startup: add pgm check info printingVasily Gorbik1-1/+1
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>
2019-07-23s390: enable detection of kernel version from bzImageVasily Gorbik1-1/+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>
2019-05-07s390/boot: fix compiler error due to missing awk strtonumMartin Schwidefsky1-1/+0
The strtonum awk function is a GNU extension and is not available with all versions of awk. The link of bzImage fails with this error message: >> awk: line 2: function or never defined >> awk: line 2: function strtonum never defined objcopy: --pad-to: bad number: arch/s390/boot/compressed/vmlinux Drop the awk script and the --pad-to objcopy parameter it generated and use a FILL pattern with an appropriate alignment in the linker script for the arch/s390/boot/compressed/vmlinux file. Fixes: f6780686525c ("s390/boot: pad bzImage to 4K") Reported-by: kbuild test robot <lkp@intel.com> Suggested-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2019-05-03s390: only build for new CPUs with clangArnd Bergmann1-6/+12
llvm does does not understand -march=z9-109 and older target specifiers, so disable the respective Kconfig settings and the logic to make the boot code work on old systems when building with clang. Part of the early boot code is normally compiled with -march=z900 for maximum compatibility. This also has to get changed with clang to the oldest supported ISA, which is -march=z10 here. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2019-04-29s390/kernel: add support for kernel address space layout randomization (KASLR)Gerald Schaefer1-0/+1
This patch adds support for relocating the kernel to a random address. The random kernel offset is obtained from cpacf, using either TRNG, PRNO, or KMC_PRNG, depending on supported MSA level. KERNELOFFSET is added to vmcoreinfo, for crash --kaslr support. 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/kernel: introduce .dma sectionsGerald Schaefer1-1/+1
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/kernel: build a relocatable kernelGerald Schaefer1-0/+1
This patch adds support for building a relocatable kernel with -fPIE. The kernel will be relocated to 0 early in the boot process. 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>
2019-04-26s390/boot: pad bzImage to 4KMartin Schwidefsky1-0/+1
In order to be able to sign the bzImage independent of the block size of the IPL device, align the bzImage to 4096 bytes. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2019-04-26s390/ipl: read IPL report at early bootMartin Schwidefsky1-2/+3
Read the IPL Report block provided by secure-boot, add the entries of the certificate list to the system key ring and print the list of components. PR: Adjust to Vasilys bootdata_preserved patch set. Preserve ipl_cert_list for later use in kexec_file. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Philipp Rudo <prudo@linux.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2019-04-10s390/uv: introduce guest side ultravisor codeVasily Gorbik1-0/+1
The Ultravisor Call Facility (stfle bit 158) defines an API to the Ultravisor (UV calls), a mini hypervisor located at machine level. With help of the Ultravisor, KVM will be able to run "protected" VMs, special VMs whose memory and management data are unavailable to KVM. The protected VMs can also request services from the Ultravisor. The guest api consists of UV calls to share and unshare memory with the kvm hypervisor. To enable this feature support PROTECTED_VIRTUALIZATION_GUEST kconfig option has been introduced. Co-developed-by: Janosch Frank <frankja@de.ibm.com> Signed-off-by: Janosch Frank <frankja@de.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2019-04-10s390: introduce .boot.preserved.data section compile time validationVasily Gorbik1-2/+2
Same as for .boot.data section make sure that .boot.preserved.data sections of vmlinux and arch/s390/compressed/vmlinux match before producing the compressed kernel image. Symbols presence, order and sizes are cross-checked. Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2019-03-13kbuild: move archive command to scripts/Makefile.libMasahiro Yamada1-3/+0
scripts/Makefile.build and arch/s390/boot/Makefile use the same command (thin archiving with symbol table creation). Avoid the code duplication, and move it to scripts/Makefile.lib. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-01-28kbuild: add real-prereqs shorthand for $(filter-out FORCE,$^)Masahiro Yamada1-1/+1
In Kbuild, if_changed and friends must have FORCE as a prerequisite. Hence, $(filter-out FORCE,$^) or $(filter-out $(PHONY),$^) is a common idiom to get the names of all the prerequisites except phony targets. Add real-prereqs as a shorthand. Note: We cannot replace $(filter %.o,$^) in cmd_link_multi-m because $^ may include auto-generated dependencies from the .*.cmd file when a single object module is changed into a multi object module. Refer to commit 69ea912fda74 ("kbuild: remove unneeded link_multi_deps"). I added some comment to avoid accidental breakage. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Acked-by: Rob Herring <robh@kernel.org>
2019-01-28s390: make built-in.a not directly depend on *.o.chkbss filesMasahiro Yamada1-2/+2
When I was refactoring cmd_ar_builtin in scripts/Makefile.build, I noticed the build breakage of s390. Some Makefiles of s390 add extra dependencies to built-in.a; built-in.a depends on timestamp files *.o.chkbss, but $(AR) does not want to include them into built-in.a. Insert a phony target 'chkbss' in between so that $(AR) can take $(filter-out $(PHONY), $^) as input. While I was here, I refactored Makefile.chkbss a little bit. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
2018-10-09s390/kasan: avoid instrumentation of early C codeVasily Gorbik1-0/+1
Instrumented C code cannot run without the kasan shadow area. Exempt source code files from kasan which are running before / used during kasan initialization. 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>
2018-10-09s390: move ipl block and cmd line handling to early boot phaseVasily Gorbik1-1/+2
To distinguish zfcpdump case and to be able to parse some of the kernel command line arguments early (e.g. mem=) ipl block retrieval and command line construction code is moved to the early boot phase. "memory_end" is set up correctly respecting "mem=" and hsa_size in case of the zfcpdump. arch/s390/boot/string.c is introduced to provide string handling and command line parsing functions to early boot phase code for the compressed kernel image case. Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2018-10-09s390: introduce .boot.data section compile time validationVasily Gorbik1-2/+18
Make sure that .boot.data sections of vmlinux and arch/s390/compressed/vmlinux match before producing the compressed kernel image. Symbols presence, order and sizes are cross-checked. 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>
2018-10-09s390/mem_detect: move tprot loop to early boot phaseVasily Gorbik1-1/+1
Move memory detection to early boot phase. To store online memory regions "struct mem_detect_info" has been introduced together with for_each_mem_detect_block iterator. mem_detect_info is later converted to memblock. Also introduces sclp_early_get_meminfo function to get maximum physical memory and maximum increment number. Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com> 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>
2018-10-09s390: remove decompressor's head.SVasily Gorbik1-1/+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>
2018-07-02s390/decompressor: avoid packing *.o.chkbss files into startup.aVasily Gorbik1-1/+1
startup.a build rule packs a list of prerequisites into archive. That didn't take into account extra prerequisites added by chkbss, so that zero length *.o.chkbss files were also packed into the archive. To avoid that filter only real object from prerequisites list. Acked-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>
2018-07-02s390/decompressor: avoid constant startup.a rebuildsVasily Gorbik1-1/+1
Correct merging error which replaced startup.a in targets list with non-existing setup.a. Due to missing startup.a in targets list if_changed triggered startup.a rebuild unconditionally. Fixes: 3e200c54438d ("s390/decompressor: avoid reusing uncompressed image objects") Acked-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: extend .bss check for early codeVasily Gorbik1-0/+4
Cover the decompressor code with no .bss usage compile time check. 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: reuse lib/mem.S for mem functionsVasily Gorbik1-1/+3
Reusing arch/s390/lib/mem.S file solves a problem that sclp_early_core.c and its dependencies have to be compiled with -march=z900 (no need to compile compressed/misc.c with -march=z900). This also allows to avoid mem functions duplicates, makes code a bit smaller and optimized mem functions are utilized. 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>
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