linux-dev/arch/s390/boot/Makefile, branch master

s390: always build relocatable kernel

2022-11-08T18:32:32Z

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 Reported-by: Nathan Chancellor Tested-by: Nathan Chancellor Link: https://lore.kernel.org/r/20221030182202.2062705-1-hca@linux.ibm.com Signed-off-by: Alexander Gordeev

s390/boot: convert initial lowcore to C

2022-05-06T18:45:15Z

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

s390/boot: get rid of startup archive

2022-05-06T18:45:14Z

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 Signed-off-by: Heiko Carstens

s390: move the install rule to arch/s390/Makefile

2021-07-30T15:09:36Z

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 Link: https://lore.kernel.org/r/20210729142338.446002-1-masahiroy@kernel.org Signed-off-by: Heiko Carstens

s390: enable KCSAN

2021-07-30T15:09:23Z

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 Signed-off-by: Heiko Carstens

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

2021-07-27T07:39:17Z

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 Acked-by: Heiko Carstens Signed-off-by: Heiko Carstens

s390/boot: enable .bss section for compressed kernel

2020-09-16T12:08:47Z

- Support static uninitialized variables in compressed kernel. - Remove chkbss script - Get rid of workarounds for not having .bss section Signed-off-by: Alexander Egorenkov Reviewed-by: Vasily Gorbik Signed-off-by: Vasily Gorbik

Merge tag 'kvmarm-5.7' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD

2020-03-31T14:44:53Z

KVM/arm updates for Linux 5.7 - GICv4.1 support - 32bit host removal

s390/protvirt: introduce host side setup

2020-02-27T18:44:40Z

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 Reviewed-by: Thomas Huth Acked-by: David Hildenbrand Reviewed-by: Cornelia Huck Acked-by: Christian Borntraeger [borntraeger@de.ibm.com: patch merging, splitting, fixing] Signed-off-by: Christian Borntraeger

s390: make 'install' not depend on vmlinux

2020-02-17T17:01:58Z

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 Signed-off-by: Vasily Gorbik