kernel.git/arch/s390/kernel/early.c, branch linux-5.4.y

s390: make PCI mio support a machine flag

2021-09-22T10:26:29Z

[ Upstream commit 3322ba0d7bea1e24ae464418626f6a15b69533ab ] Kernel support for the newer PCI mio instructions can be toggled off with the pci=nomio command line option which needs to integrate with common code PCI option parsing. However this option then toggles static branches which can't be toggled yet in an early_param() call. Thus commit 9964f396f1d0 ("s390: fix setting of mio addressing control") moved toggling the static branches to the PCI init routine. With this setup however we can't check for mio support outside the PCI code during early boot, i.e. before switching the static branches, which we need to be able to export this as an ELF HWCAP. Improve on this by turning mio availability into a machine flag that gets initially set based on CONFIG_PCI and the facility bit and gets toggled off if pci=nomio is found during PCI option parsing allowing simple access to this machine flag after early init. Reviewed-by: Heiko Carstens Signed-off-by: Niklas Schnelle Signed-off-by: Heiko Carstens Signed-off-by: Sasha Levin

s390/kasan: fix early pgm check handler execution

2020-07-16T06:16:35Z

[ Upstream commit 998f5bbe3dbdab81c1cfb1aef7c3892f5d24f6c7 ] Currently if early_pgm_check_handler is called it ends up in pgm check loop. The problem is that early_pgm_check_handler is instrumented by KASAN but executed without DAT flag enabled which leads to addressing exception when KASAN checks try to access shadow memory. Fix that by executing early handlers with DAT flag on under KASAN as expected. Reported-and-tested-by: Alexander Egorenkov Reviewed-by: Heiko Carstens Signed-off-by: Vasily Gorbik Signed-off-by: Heiko Carstens Signed-off-by: Sasha Levin

s390: clean .bss before running uncompressed kernel

2019-08-21T10:58:52Z

Clean uncompressed kernel .bss section in the startup code before the uncompressed kernel is executed. At this point of time initrd and certificates have been already rescued. Uncompressed kernel .bss size is known from vmlinux_info. It is also taken into consideration during uncompressed kernel positioning by kaslr (so it is safe to clean it). With that uncompressed kernel is starting with .bss section zeroed and no .bss section usage restrictions apply. Which makes chkbss checks for uncompressed kernel objects obsolete and they can be removed. early_nobss.c is also not needed anymore. Parts of it which are still relevant are moved to early.c. Kasan initialization code is now called directly from head64 (early.c is instrumented and should not be executed before kasan shadow memory is set up). Reviewed-by: Philipp Rudo Signed-off-by: Vasily Gorbik

s390: fix setting of mio addressing control

2019-07-11T18:40:02Z

Move enablement of mio addressing control from detect_machine_facilities to pci_base_init. detect_machine_facilities runs so early that the static branches have not been toggled yet, thus mio addressing control was always off. In pci_base_init we have to use the SMP aware ctl_set_bit though. Fixes: 833b441ec0f6 ("s390: enable processes for mio instructions") Signed-off-by: Sebastian Ott Signed-off-by: Vasily Gorbik

s390: simplify disabled_wait

2019-05-02T11:54:11Z

The disabled_wait() function uses its argument as the PSW address when it stops the CPU with a wait PSW that is disabled for interrupts. The different callers sometimes use a specific number like 0xdeadbeef to indicate a specific failure, the early boot code uses 0 and some other calls sites use __builtin_return_address(0). At the time a dump is created the current PSW and the registers of a CPU are written to lowcore to make them avaiable to the dump analysis tool. For a CPU stopped with disabled_wait the PSW and the registers do not really make sense together, the PSW address does not point to the function the registers belong to. Simplify disabled_wait() by using _THIS_IP_ for the PSW address and drop the argument to the function. Signed-off-by: Martin Schwidefsky

s390/kernel: introduce .dma sections

2019-04-29T08:47:10Z

With a relocatable kernel that could reside at any place in memory, code and data that has to stay below 2 GB needs special handling. This patch introduces .dma sections for such text, data and ex_table. The sections will be part of the decompressor kernel, so they will not be relocated and stay below 2 GB. Their location is passed over to the decompressed / relocated kernel via the .boot.preserved.data section. The duald and aste for control register setup also need to stay below 2 GB, so move the setup code from arch/s390/kernel/head64.S to arch/s390/boot/head.S. The duct and linkage_stack could reside above 2 GB, but their content has to be preserved for the decompresed kernel, so they are also moved into the .dma section. The start and end address of the .dma sections is added to vmcoreinfo, for crash support, to help debugging in case the kernel crashed there. Signed-off-by: Gerald Schaefer Reviewed-by: Philipp Rudo Signed-off-by: Martin Schwidefsky

s390: enable processes for mio instructions

2019-04-29T08:47:01Z

Allow for userspace to use PCI MIO instructions. Signed-off-by: Sebastian Ott Signed-off-by: Martin Schwidefsky

s390: move ipl block to .boot.preserved.data section

2019-04-10T15:47:11Z

.boot.preserved.data is a better fit for ipl block than .boot.data which is discarded after init. Reusing .boot.preserved.data allows to simplify code a little bit and avoid copying data from .boot.data to persistent variables. Signed-off-by: Vasily Gorbik Signed-off-by: Martin Schwidefsky

Merge tag 's390-5.1-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux

2019-03-05T19:13:10Z

Pull s390 updates from Martin Schwidefsky: - A copy of Arnds compat wrapper generation series - Pass information about the KVM guest to the host in form the control program code and the control program version code - Map IOV resources to support PCI physical functions on s390 - Add vector load and store alignment hints to improve performance - Use the "jdd" constraint with gcc 9 to make jump labels working again - Remove amode workaround for old z/VM releases from the DCSS code - Add support for in-kernel performance measurements using the CPU measurement counter facility - Introduce a new PMU device cpum_cf_diag to capture counters and store thenn as event raw data. - Bug fixes and cleanups * tag 's390-5.1-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (54 commits) Revert "s390/cpum_cf: Add kernel message exaplanations" s390/dasd: fix read device characteristic with CONFIG_VMAP_STACK=y s390/suspend: fix prefix register reset in swsusp_arch_resume s390: warn about clearing als implied facilities s390: allow overriding facilities via command line s390: clean up redundant facilities list setup s390/als: remove duplicated in-place implementation of stfle s390/cio: Use cpa range elsewhere within vfio-ccw s390/cio: Fix vfio-ccw handling of recursive TICs s390: vfio_ap: link the vfio_ap devices to the vfio_ap bus subsystem s390/cpum_cf: Handle EBUSY return code from CPU counter facility reservation s390/cpum_cf: Add kernel message exaplanations s390/cpum_cf_diag: Add support for s390 counter facility diagnostic trace s390/cpum_cf: add ctr_stcctm() function s390/cpum_cf: move common functions into a separate file s390/cpum_cf: introduce kernel_cpumcf_avail() function s390/cpu_mf: replace stcctm5() with the stcctm() function s390/cpu_mf: add store cpu counter multiple instruction support s390/cpum_cf: Add minimal in-kernel interface for counter measurements s390/cpum_cf: introduce kernel_cpumcf_alert() to obtain measurement alerts ...

s390: clean up redundant facilities list setup

2019-03-01T07:00:39Z

Facilities list in the lowcore is initially set up by verify_facilities from als.c and later initializations are redundant, so cleaning them up. Reviewed-by: Heiko Carstens Signed-off-by: Vasily Gorbik Signed-off-by: Martin Schwidefsky