wireguard-linux/arch/s390/kernel, 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/mm: Prevent lowcore vs identity mapping overlap

2024-08-21T14:14:45Z

The identity mapping position in virtual memory is randomized together with the kernel mapping. That position can never overlap with the lowcore even when the lowcore is relocated. Prevent overlapping with the lowcore to allow independent positioning of the identity mapping. With the current value of the alternative lowcore address of 0x70000 the overlap could happen in case the identity mapping is placed at zero. This is a prerequisite for uncoupling of randomization base of kernel image and identity mapping in virtual memory. Acked-by: Vasily Gorbik Signed-off-by: Alexander Gordeev Signed-off-by: Vasily Gorbik

s390/vmlinux.lds.S: Move ro_after_init section behind rodata section

2024-07-31T14:30:20Z

The .data.rel.ro and .got section were added between the rodata and ro_after_init data section, which adds an RW mapping in between all RO mapping of the kernel image: ---[ Kernel Image Start ]--- 0x000003ffe0000000-0x000003ffe0e00000 14M PMD RO X 0x000003ffe0e00000-0x000003ffe0ec7000 796K PTE RO X 0x000003ffe0ec7000-0x000003ffe0f00000 228K PTE RO NX 0x000003ffe0f00000-0x000003ffe1300000 4M PMD RO NX 0x000003ffe1300000-0x000003ffe1331000 196K PTE RO NX 0x000003ffe1331000-0x000003ffe13b3000 520K PTE RW NX <--- 0x000003ffe13b3000-0x000003ffe13d5000 136K PTE RO NX 0x000003ffe13d5000-0x000003ffe1400000 172K PTE RW NX 0x000003ffe1400000-0x000003ffe1500000 1M PMD RW NX 0x000003ffe1500000-0x000003ffe1700000 2M PTE RW NX 0x000003ffe1700000-0x000003ffe1800000 1M PMD RW NX 0x000003ffe1800000-0x000003ffe187e000 504K PTE RW NX ---[ Kernel Image End ]--- Move the ro_after_init data section again right behind the rodata section to prevent interleaving RO and RW mappings: ---[ Kernel Image Start ]--- 0x000003ffe0000000-0x000003ffe0e00000 14M PMD RO X 0x000003ffe0e00000-0x000003ffe0ec7000 796K PTE RO X 0x000003ffe0ec7000-0x000003ffe0f00000 228K PTE RO NX 0x000003ffe0f00000-0x000003ffe1300000 4M PMD RO NX 0x000003ffe1300000-0x000003ffe1353000 332K PTE RO NX 0x000003ffe1353000-0x000003ffe1400000 692K PTE RW NX 0x000003ffe1400000-0x000003ffe1500000 1M PMD RW NX 0x000003ffe1500000-0x000003ffe1700000 2M PTE RW NX 0x000003ffe1700000-0x000003ffe1800000 1M PMD RW NX 0x000003ffe1800000-0x000003ffe187e000 504K PTE RW NX ---[ Kernel Image End ]--- Reviewed-by: Alexander Gordeev Signed-off-by: Heiko Carstens Signed-off-by: Vasily Gorbik

s390/alternatives: Remove unused empty header file

2024-07-31T14:30:20Z

Remove the unused and empty arch/s390/kernel/alternative.h header file which was added by mistake. Fixes: 5ade5be4edf8 ("s390: Add infrastructure to patch lowcore accesses") Signed-off-by: Heiko Carstens Signed-off-by: Vasily Gorbik

s390/fpu: Re-add exception handling in load_fpu_state()

2024-07-31T14:30:20Z

With the recent rewrite of the fpu code exception handling for the lfpc instruction within load_fpu_state() was erroneously removed. Add it again to prevent that loading invalid floating point register values cause an unhandled specification exception. Fixes: 8c09871a950a ("s390/fpu: limit save and restore to used registers") Cc: stable@vger.kernel.org Reported-by: Aristeu Rozanski Tested-by: Aristeu Rozanski Reviewed-by: Vasily Gorbik Signed-off-by: Heiko Carstens 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 ...

sysctl: treewide: constify the ctl_table argument of proc_handlers

2024-07-24T18:59:29Z

const qualify the struct ctl_table argument in the proc_handler function signatures. This is a prerequisite to moving the static ctl_table structs into .rodata data which will ensure that proc_handler function pointers cannot be modified. This patch has been generated by the following coccinelle script: ``` virtual patch @r1@ identifier ctl, write, buffer, lenp, ppos; identifier func !~ "appldata_(timer|interval)_handler|sched_(rt|rr)_handler|rds_tcp_skbuf_handler|proc_sctp_do_(hmac_alg|rto_min|rto_max|udp_port|alpha_beta|auth|probe_interval)"; @@ int func( - struct ctl_table *ctl + const struct ctl_table *ctl ,int write, void *buffer, size_t *lenp, loff_t *ppos); @r2@ identifier func, ctl, write, buffer, lenp, ppos; @@ int func( - struct ctl_table *ctl + const struct ctl_table *ctl ,int write, void *buffer, size_t *lenp, loff_t *ppos) { ... } @r3@ identifier func; @@ int func( - struct ctl_table * + const struct ctl_table * ,int , void *, size_t *, loff_t *); @r4@ identifier func, ctl; @@ int func( - struct ctl_table *ctl + const struct ctl_table *ctl ,int , void *, size_t *, loff_t *); @r5@ identifier func, write, buffer, lenp, ppos; @@ int func( - struct ctl_table * + const struct ctl_table * ,int write, void *buffer, size_t *lenp, loff_t *ppos); ``` * Code formatting was adjusted in xfs_sysctl.c to comply with code conventions. The xfs_stats_clear_proc_handler, xfs_panic_mask_proc_handler and xfs_deprecated_dointvec_minmax where adjusted. * The ctl_table argument in proc_watchdog_common was const qualified. This is called from a proc_handler itself and is calling back into another proc_handler, making it necessary to change it as part of the proc_handler migration. Co-developed-by: Thomas Weißschuh Signed-off-by: Thomas Weißschuh Co-developed-by: Joel Granados Signed-off-by: Joel Granados

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/kdump: Make kdump ready for lowcore relocation

2024-07-23T14:02:32Z

In preparation of having lowcore at different address than zero, add the base register to all lowcore accesses in store_status() and __do_machine_kdump(). Reviewed-by: Heiko Carstens Signed-off-by: Sven Schnelle Signed-off-by: Vasily Gorbik

s390/entry: Make system_call() ready for lowcore relocation

2024-07-23T14:02:32Z

In preparation of having lowcore at different address than zero, add the base register to all lowcore accesses in system_call(). Reviewed-by: Heiko Carstens Signed-off-by: Sven Schnelle Signed-off-by: Vasily Gorbik