kernel/arch/s390/include/asm/processor.h, branch linux-5.1.y

compiler: remove __no_sanitize_address_or_inline again

2018-11-05T16:14:18Z

The __no_sanitize_address_or_inline and __no_kasan_or_inline defines are almost identical. The only difference is that __no_kasan_or_inline does not have the 'notrace' attribute. To be able to replace __no_sanitize_address_or_inline with the older definition, add 'notrace' to __no_kasan_or_inline and change to two users of __no_sanitize_address_or_inline in the s390 code. The 'notrace' option is necessary for e.g. the __load_psw_mask function in arch/s390/include/asm/processor.h. Without the option it is possible to trace __load_psw_mask which leads to kernel stack overflow. Signed-off-by: Martin Schwidefsky Pointed-out-by: Andrey Ryabinin Acked-by: Steven Rostedt (VMware) Signed-off-by: Linus Torvalds

treewide: remove current_text_addr

2018-10-31T15:54:12Z

Prefer _THIS_IP_ defined in linux/kernel.h. Most definitions of current_text_addr were the same as _THIS_IP_, but a few archs had inline assembly instead. This patch removes the final call site of current_text_addr, making all of the definitions dead code. [akpm@linux-foundation.org: fix arch/csky/include/asm/processor.h] Link: http://lkml.kernel.org/r/20180911182413.180715-1-ndesaulniers@google.com Signed-off-by: Nick Desaulniers Cc: Peter Zijlstra Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

s390/kasan: reipl and kexec support

2018-10-09T09:21:27Z

Some functions from both arch/s390/kernel/ipl.c and arch/s390/kernel/machine_kexec.c are called without DAT enabled (or with and without DAT enabled code paths). There is no easy way to partially disable kasan for those files without a substantial rework. Disable kasan for both files for now. To avoid disabling kasan for arch/s390/kernel/diag.c DAT flag is enabled in diag308 call. pcpu_delegate which disables DAT is marked with __no_sanitize_address to disable instrumentation for that one function. Signed-off-by: Vasily Gorbik Signed-off-by: Martin Schwidefsky

s390/smp: kasan stack instrumentation support

2018-10-09T09:21:26Z

smp_start_secondary function is called without DAT enabled. To avoid disabling kasan instrumentation for entire arch/s390/kernel/smp.c smp_start_secondary has been split in 2 parts. smp_start_secondary has instrumentation disabled, it does minimal setup and enables DAT. Then instrumentated __smp_start_secondary is called to do the rest. __load_psw_mask function instrumentation has been disabled as well to be able to call it from smp_start_secondary. Reviewed-by: Martin Schwidefsky Signed-off-by: Vasily Gorbik Signed-off-by: Martin Schwidefsky

s390: unify stack size definitions

2018-10-09T09:20:58Z

Remove STACK_ORDER and STACK_SIZE in favour of identical THREAD_SIZE_ORDER and THREAD_SIZE definitions. THREAD_SIZE and THREAD_SIZE_ORDER naming is misleading since it is used as general kernel stack size information. But both those definitions are used in the common code and throughout architectures specific code, so changing the naming is problematic. Reviewed-by: Martin Schwidefsky Signed-off-by: Vasily Gorbik Signed-off-by: Martin Schwidefsky

s390: add support for virtually mapped kernel stacks

2018-10-09T09:20:57Z

With virtually mapped kernel stacks the kernel stack overflow detection is now fault based, every stack has a guard page in the vmalloc space. The panic_stack is renamed to nodat_stack and is used for all function that need to run without DAT, e.g. memcpy_real or do_start_kdump. The main effect is a reduction in the kernel image size as with vmap stacks the old style overflow checking that adds two instructions per function is not needed anymore. Result from bloat-o-meter: add/remove: 20/1 grow/shrink: 13/26854 up/down: 2198/-216240 (-214042) In regard to performance the micro-benchmark for fork has a hit of a few microseconds, allocating 4 pages in vmalloc space is more expensive compare to an order-2 page allocation. But with real workload I could not find a noticeable difference. Acked-by: Heiko Carstens Signed-off-by: Martin Schwidefsky

s390: add stack switch helper

2018-10-09T09:20:56Z

Reviewed-by: Heiko Carstens Signed-off-by: Martin Schwidefsky

s390: run user space and KVM guests with modified branch prediction

2018-02-05T13:48:50Z

Define TIF_ISOLATE_BP and TIF_ISOLATE_BP_GUEST and add the necessary plumbing in entry.S to be able to run user space and KVM guests with limited branch prediction. To switch a user space process to limited branch prediction the s390_isolate_bp() function has to be call, and to run a vCPU of a KVM guest associated with the current task with limited branch prediction call s390_isolate_bp_guest(). Signed-off-by: Martin Schwidefsky

s390: add options to change branch prediction behaviour for the kernel

2018-02-05T12:49:17Z

Add the PPA instruction to the system entry and exit path to switch the kernel to a different branch prediction behaviour. The instructions are added via CPU alternatives and can be disabled with the "nospec" or the "nobp=0" kernel parameter. If the default behaviour selected with CONFIG_KERNEL_NOBP is set to "n" then the "nobp=1" parameter can be used to enable the changed kernel branch prediction. Acked-by: Cornelia Huck Signed-off-by: Martin Schwidefsky

s390: correct some inline assembly constraints

2017-11-14T10:01:51Z

Inline assembly code changed in this patch should really use "Q" constraint "Memory reference without index register and with short displacement". The kernel does not compile with kasan support enabled otherwise (due to stack instrumentation). Signed-off-by: Vasily Gorbik Signed-off-by: Heiko Carstens