wireguard-linux/arch/s390/boot, branch jd/bump-compilers

s390/boot: Fix KASLR base offset off by __START_KERNEL bytes

2024-08-22T17:24:13Z

Symbol offsets to the KASLR base do not match symbol address in the vmlinux image. That is the result of setting the KASLR base to the beginning of .text section as result of an optimization. Revert that optimization and allocate virtual memory for the whole kernel image including __START_KERNEL bytes as per the linker script. That allows keeping the semantics of the KASLR base offset in sync with other architectures. Rename __START_KERNEL to TEXT_OFFSET, since it represents the offset of the .text section within the kernel image, rather than a virtual address. Still skip mapping TEXT_OFFSET bytes to save memory on pgtables and provoke exceptions in case an attempt to access this area is made, as no kernel symbol may reside there. In case CONFIG_KASAN is enabled the location counter might exceed the value of TEXT_OFFSET, while the decompressor linker script forcefully resets it to TEXT_OFFSET, which leads to a sections overlap link failure. Use MAX() expression to avoid that. Reported-by: Omar Sandoval Closes: https://lore.kernel.org/linux-s390/ZnS8dycxhtXBZVky@telecaster.dhcp.thefacebook.com/ Fixes: 56b1069c40c7 ("s390/boot: Rework deployment of the kernel image") Signed-off-by: Alexander Gordeev Acked-by: Vasily Gorbik Signed-off-by: Vasily Gorbik

s390/boot: Avoid possible physmem_info segment corruption

2024-08-22T17:24:13Z

When physical memory for the kernel image is allocated it does not consider extra memory required for offsetting the image start to match it with the lower 20 bits of KASLR virtual base address. That might lead to kernel access beyond its memory range. Suggested-by: Vasily Gorbik Fixes: 693d41f7c938 ("s390/mm: Restore mapping of kernel image using large pages") Signed-off-by: Alexander Gordeev Acked-by: Vasily Gorbik Signed-off-by: Vasily Gorbik

s390/mm: Pin identity mapping base to zero

2024-08-21T14:14:45Z

SIE instruction performs faster when the virtual address of SIE block matches the physical one. Pin the identity mapping base to zero for the benefit of SIE and other instructions that have similar performance impact. Still, randomize the base when DEBUG_VM kernel configuration option is enabled. Suggested-by: Vasily Gorbik Reviewed-by: Christian Borntraeger Signed-off-by: Alexander Gordeev Signed-off-by: Vasily Gorbik

Merge tag 's390-6.11-2' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux

2024-07-26T17:47:53Z

Pull more s390 updates from Vasily Gorbik: - Fix KMSAN build breakage caused by the conflict between s390 and mm-stable trees - Add KMSAN page markers for ptdump - Add runtime constant support - Fix __pa/__va for modules under non-GPL licenses by exporting necessary vm_layout struct with EXPORT_SYMBOL to prevent linkage problems - Fix an endless loop in the CF_DIAG event stop in the CPU Measurement Counter Facility code when the counter set size is zero - Remove the PROTECTED_VIRTUALIZATION_GUEST config option and enable its functionality by default - Support allocation of multiple MSI interrupts per device and improve logging of architecture-specific limitations - Add support for lowcore relocation as a debugging feature to catch all null ptr dereferences in the kernel address space, improving detection beyond the current implementation's limited write access protection - Clean up and rework CPU alternatives to allow for callbacks and early patching for the lowcore relocation * tag 's390-6.11-2' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (39 commits) s390: Remove protvirt and kvm config guards for uv code s390/boot: Add cmdline option to relocate lowcore s390/kdump: Make kdump ready for lowcore relocation s390/entry: Make system_call() ready for lowcore relocation s390/entry: Make ret_from_fork() ready for lowcore relocation s390/entry: Make __switch_to() ready for lowcore relocation s390/entry: Make restart_int_handler() ready for lowcore relocation s390/entry: Make mchk_int_handler() ready for lowcore relocation s390/entry: Make int handlers ready for lowcore relocation s390/entry: Make pgm_check_handler() ready for lowcore relocation s390/entry: Add base register to CHECK_VMAP_STACK/CHECK_STACK macro s390/entry: Add base register to SIEEXIT macro s390/entry: Add base register to MBEAR macro s390/entry: Make __sie64a() ready for lowcore relocation s390/head64: Make startup code ready for lowcore relocation s390: Add infrastructure to patch lowcore accesses s390/atomic_ops: Disable flag outputs constraint for GCC versions below 14.2.0 s390/entry: Move SIE indicator flag to thread info s390/nmi: Simplify ptregs setup s390/alternatives: Remove alternative facility list ...

Merge tag 'kbuild-v6.11' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

2024-07-23T21:32:21Z

Pull Kbuild updates from Masahiro Yamada: - Remove tristate choice support from Kconfig - Stop using the PROVIDE() directive in the linker script - Reduce the number of links for the combination of CONFIG_KALLSYMS and CONFIG_DEBUG_INFO_BTF - Enable the warning for symbol reference to .exit.* sections by default - Fix warnings in RPM package builds - Improve scripts/make_fit.py to generate a FIT image with separate base DTB and overlays - Improve choice value calculation in Kconfig - Fix conditional prompt behavior in choice in Kconfig - Remove support for the uncommon EMAIL environment variable in Debian package builds - Remove support for the uncommon "name " form for the DEBEMAIL environment variable - Raise the minimum supported GNU Make version to 4.0 - Remove stale code for the absolute kallsyms - Move header files commonly used for host programs to scripts/include/ - Introduce the pacman-pkg target to generate a pacman package used in Arch Linux - Clean up Kconfig * tag 'kbuild-v6.11' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (65 commits) kbuild: doc: gcc to CC change kallsyms: change sym_entry::percpu_absolute to bool type kallsyms: unify seq and start_pos fields of struct sym_entry kallsyms: add more original symbol type/name in comment lines kallsyms: use \t instead of a tab in printf() kallsyms: avoid repeated calculation of array size for markers kbuild: add script and target to generate pacman package modpost: use generic macros for hash table implementation kbuild: move some helper headers from scripts/kconfig/ to scripts/include/ Makefile: add comment to discourage tools/* addition for kernel builds kbuild: clean up scripts/remove-stale-files kconfig: recursive checks drop file/lineno kbuild: rpm-pkg: introduce a simple changelog section for kernel.spec kallsyms: get rid of code for absolute kallsyms kbuild: Create INSTALL_PATH directory if it does not exist kbuild: Abort make on install failures kconfig: remove 'e1' and 'e2' macros from expression deduplication kconfig: remove SYMBOL_CHOICEVAL flag kconfig: add const qualifiers to several function arguments kconfig: call expr_eliminate_yn() at least once in expr_eliminate_dups() ...

s390: Remove protvirt and kvm config guards for uv code

2024-07-23T14:02:33Z

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 Acked-by: Christian Borntraeger Acked-by: Heiko Carstens Signed-off-by: Vasily Gorbik

s390/boot: Add cmdline option to relocate lowcore

2024-07-23T14:02:32Z

Now that everything has been converted, add the option 'relocate_lowcore' to enable relocating the lowcore. Reviewed-by: Heiko Carstens Signed-off-by: Sven Schnelle Signed-off-by: Vasily Gorbik

s390: Add infrastructure to patch lowcore accesses

2024-07-23T14:02:32Z

The s390 architecture defines two special per-CPU data pages called the "prefix area". In s390-linux terminology this is usually called "lowcore". This memory area contains system configuration data like old/new PSW's for system call/interrupt/machine check handlers and lots of other data. It is normally mapped to logical address 0. This area can only be accessed when in supervisor mode. This means that kernel code can dereference NULL pointers, because accesses to address 0 are allowed. Parts of lowcore can be write protected, but read accesses and write accesses outside of the write protected areas are not caught. To remove this limitation for debugging and testing, remap lowcore to another address and define a function get_lowcore() which simply returns the address where lowcore is mapped at. This would normally introduce a pointer dereference (=memory read). As lowcore is used for several very often used variables, add code to patch this function during runtime, so we avoid the memory reads. For C code get_lowcore() has to be used, for assembly code it is the GET_LC macro. When using this macro/function a reference is added to alternative patching. All these locations will be patched to the actual lowcore location when the kernel is booted or a module is loaded. To make debugging/bisecting problems easier, this patch adds all the infrastructure but the lowcore address is still hardwired to 0. This way the code can be converted on a per function basis, and the functionality is enabled in a patch after all the functions have been converted. Note that this requires at least z16 because the old lpsw instruction only allowed a 12 bit displacement. z16 introduced lpswey which allows 20 bits (signed), so the lowcore can effectively be mapped from address 0 - 0x7e000. To use 0x7e000 as address, a 6 byte lgfi instruction would have to be used in the alternative. To save two bytes, llilh can be used, but this only allows to set bits 16-31 of the address. In order to use the llilh instruction, use 0x70000 as alternative lowcore address. This is still large enough to catch NULL pointer dereferences into large arrays. Reviewed-by: Heiko Carstens Signed-off-by: Sven Schnelle Signed-off-by: Vasily Gorbik

s390/alternatives: Allow early alternative patching in decompressor

2024-07-23T14:02:31Z

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 Co-developed-by: Heiko Carstens Signed-off-by: Heiko Carstens Signed-off-by: Sven Schnelle Signed-off-by: Vasily Gorbik

s390/boot: Do not assume the decompressor range is reserved

2024-07-23T14:02:30Z

When allocating a random memory range for .amode31 sections the minimal randomization address is 0. That does not lead to a possible overlap with the decompressor image (which also starts from 0) since by that time the image range is already reserved. Do not assume the decompressor range is reserved and always provide the minimal randomization address for .amode31 sections beyond the decompressor. That is a prerequisite for moving the lowcore memory address from NULL elsewhere. Signed-off-by: Alexander Gordeev Signed-off-by: Sven Schnelle Signed-off-by: Vasily Gorbik