linux-dev/arch/s390/kernel/nospec-branch.c, branch linus/master

s390: raise minimum supported machine generation to z10

2022-03-10T14:58:17Z

Machine generations up to z9 (released in May 2006) have been officially out of service for several years now (z9 end of service - January 31, 2019). No distributions build kernels supporting those old machine generations anymore, except Debian, which seems to pick the oldest supported generation. The team supporting Debian on s390 has been notified about the change. Raising minimum supported machine generation to z10 helps to reduce maintenance cost and effectively remove code, which is not getting enough testing coverage due to lack of older hardware and distributions support. Besides that this unblocks some optimization opportunities and allows to use wider instruction set in asm files for future features implementation. Due to this change spectre mitigation and usercopy implementations could be drastically simplified and many newer instructions could be converted from ".insn" encoding to instruction names. Acked-by: Ilya Leoshkevich Reviewed-by: Heiko Carstens Signed-off-by: Vasily Gorbik

s390: remove unused expoline to BC instructions

2022-03-07T23:33:01Z

This reverts commit 6deaa3bbca80 ("s390: extend expoline to BC instructions"). Expolines to BC instructions were added to be utilized by commit de5cb6eb514e ("s390: use expoline thunks in the BPF JIT"). But corresponding code has been removed by commit e1cf4befa297 ("bpf, s390x: remove ld_abs/ld_ind"). And compiler does not generate such expolines as well. Compared to regular expolines, expolines to BC instructions contain displacement and all possible variations cannot be generated in advance, making kpatch support more complicated. So, remove those to avoid future usages. Acked-by: Heiko Carstens Acked-by: Sumanth Korikkar Signed-off-by: Vasily Gorbik

s390: introduce nospec_uses_trampoline()

2021-10-26T13:21:29Z

and replace all of the "__is_defined(CC_USING_EXPOLINE) && !nospec_disable" occurrences. Signed-off-by: Sven Schnelle Reviewed-by: Heiko Carstens Signed-off-by: Vasily Gorbik

s390/speculation: Use statically initialized const for instructions

2021-06-28T09:18:28Z

In preparation for FORTIFY_SOURCE performing compile-time and run-time field bounds checking for memcpy(), memmove(), and memset(), avoid confusing the checks when using a static const source. Move the static const array into a variable so the compiler can perform appropriate bounds checking. Signed-off-by: Kees Cook Link: https://lore.kernel.org/r/20210616201823.1245603-1-keescook@chromium.org Signed-off-by: Vasily Gorbik

s390/facilities: move stfl information from lowcore to global data

2021-06-07T15:06:58Z

With gcc-11, there are a lot of warnings because the facility functions are accessing lowcore through a null pointer. Fix this by moving the facility arrays away from lowcore. Signed-off-by: Sven Schnelle Signed-off-by: Heiko Carstens Signed-off-by: Vasily Gorbik

Merge tag 's390-5.2-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux

2019-05-06T23:42:54Z

Pull s390 updates from Martin Schwidefsky: - Support for kernel address space layout randomization - Add support for kernel image signature verification - Convert s390 to the generic get_user_pages_fast code - Convert s390 to the stack unwind API analog to x86 - Add support for CPU directed interrupts for PCI devices - Provide support for MIO instructions to the PCI base layer, this will allow the use of direct PCI mappings in user space code - Add the basic KVM guest ultravisor interface for protected VMs - Add AT_HWCAP bits for several new hardware capabilities - Update the CPU measurement facility counter definitions to SVN 6 - Arnds cleanup patches for his quest to get LLVM compiles working - A vfio-ccw update with bug fixes and support for halt and clear - Improvements for the hardware TRNG code - Another round of cleanup for the QDIO layer - Numerous cleanups and bug fixes * tag 's390-5.2-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (98 commits) s390/vdso: drop unnecessary cc-ldoption s390: fix clang -Wpointer-sign warnigns in boot code s390: drop CONFIG_VIRT_TO_BUS s390: boot, purgatory: pass $(CLANG_FLAGS) where needed s390: only build for new CPUs with clang s390: simplify disabled_wait s390/ftrace: use HAVE_FUNCTION_GRAPH_RET_ADDR_PTR s390/unwind: introduce stack unwind API s390/opcodes: add missing instructions to the disassembler s390/bug: add entry size to the __bug_table section s390: use proper expoline sections for .dma code s390/nospec: rename assembler generated expoline thunks s390: add missing ENDPROC statements to assembler functions locking/lockdep: check for freed initmem in static_obj() s390/kernel: add support for kernel address space layout randomization (KASLR) s390/kernel: introduce .dma sections s390/sclp: do not use static sccbs s390/kprobes: use static buffer for insn_page s390/kernel: convert SYSCALL and PGM_CHECK handlers to .quad s390/kernel: build a relocatable kernel ...

s390/speculation: Support 'mitigations=' cmdline option

2019-04-17T19:37:29Z

Configure s390 runtime CPU speculation bug mitigations in accordance with the 'mitigations=' cmdline option. This affects Spectre v1 and Spectre v2. The default behavior is unchanged. Signed-off-by: Josh Poimboeuf Signed-off-by: Thomas Gleixner Tested-by: Jiri Kosina (on x86) Reviewed-by: Jiri Kosina Cc: Borislav Petkov Cc: "H . Peter Anvin" Cc: Andy Lutomirski Cc: Peter Zijlstra Cc: Jiri Kosina Cc: Waiman Long Cc: Andrea Arcangeli Cc: Jon Masters Cc: Benjamin Herrenschmidt Cc: Paul Mackerras Cc: Michael Ellerman Cc: linuxppc-dev@lists.ozlabs.org Cc: Martin Schwidefsky Cc: Heiko Carstens Cc: linux-s390@vger.kernel.org Cc: Catalin Marinas Cc: Will Deacon Cc: linux-arm-kernel@lists.infradead.org Cc: linux-arch@vger.kernel.org Cc: Greg Kroah-Hartman Cc: Tyler Hicks Cc: Linus Torvalds Cc: Randy Dunlap Cc: Steven Price Cc: Phil Auld Link: https://lkml.kernel.org/r/e4a161805458a5ec88812aac0307ae3908a030fc.1555085500.git.jpoimboe@redhat.com

s390: Convert IS_ENABLED uses to __is_defined

2019-04-11T11:36:53Z

IS_ENABLED should be reserved for CONFIG_ uses so convert the uses of IS_ENABLED with a #define to __is_defined. Signed-off-by: Joe Perches Signed-off-by: Martin Schwidefsky

s390: detect etoken facility

2018-07-18T06:32:17Z

Detect and report the etoken facility. With spectre_v2=auto or CONFIG_EXPOLINE_AUTO=y automatically disable expolines and use the full branch prediction mode for the kernel. Signed-off-by: Martin Schwidefsky

s390: remove closung punctuation from spectre messages

2018-05-09T08:55:01Z

There should not be a '.' at the end of the spectre syslog messages. Remove them. Signed-off-by: Martin Schwidefsky