kernel/arch/s390/include/asm/elf.h, branch linux-6.2.y

s390/hwcaps: make sie capability regular hwcap

2021-07-27T07:39:21Z

Commit 7f16d7e787b7 ("s390: show virtualization support in /proc/cpuinfo") introduced special handling for sie capability, saying this should not be exposed via hwcaps, without giving a reason. However this leads to an inconsistent /proc/cpuinfo features line where all features except the sie capability are also present in hwcaps. I really don't see a reason to not add that to hwcaps - it might be quite pointless, but at least this way it is possible to get rid of some special handling. Signed-off-by: Heiko Carstens

s390/hwcaps: add sanity checks

2021-07-27T07:39:20Z

Add BUILD_BUG_ON() sanity checks to make sure the hwcap string array contains a string for each hwcap. Signed-off-by: Heiko Carstens

s390/hwcaps: introduce HWCAP bit numbers

2021-07-27T07:39:20Z

Introduce HWCAP bit numbers, making it easier to tell at which bit number we currently are. Also use these bits with the BIT macro to define the real HWCAP masks. Signed-off-by: Heiko Carstens

s390/hwcaps: shorten HWCAP defines

2021-07-27T07:39:20Z

Remove s390 part of all HWCAP defines, just to make them shorter and easier to handle. The namespace is anyway per architecture. This is similar to what arm64 has. Signed-off-by: Heiko Carstens

s390: add HWCAP_S390_PCI_MIO to ELF hwcaps

2021-07-27T07:39:19Z

In order to support the use of enhanced PCI instructions in both kernel- and userspace we need both hardware support and proper setup in the kernel. The latter can be toggled off with the pci=nomio command line option. Thus availability of this feature in userspace depends on all of kernel configuration (CONFIG_PCI), hardware support and the current kernel command line and can thus not rely solely on a facility bit. Instead let's introduce a new ELF hardware capability bit HWCAP_S390_PCI_MIO to tell userspace whether these PCI instructions can be used. Reviewed-by: Heiko Carstens Signed-off-by: Niklas Schnelle Signed-off-by: Heiko Carstens

s390: report more CPU capabilities

2021-07-27T07:39:19Z

Add hardware capability bits and feature tags to /proc/cpuinfo for NNPA and Vector-Packed-Decimal-Enhancement Facility 2. Signed-off-by: Heiko Carstens

s390: rename PIF_SYSCALL_RESTART to PIF_EXECVE_PGSTE_RESTART

2021-07-08T20:12:17Z

PIF_SYSCALL_RESTART is now only used to restart execve when loading PGSTE binaries. Rename the flag to reflect that, and avoid people thinking that this bit has anything to do with generic syscall restarting. Signed-off-by: Sven Schnelle Reviewed-by: Heiko Carstens Signed-off-by: Vasily Gorbik

s390/vdso: add minimal compat vdso

2021-07-08T13:37:28Z

Add a small vdso for 31 bit compat application that provides trampolines for calls to sigreturn,rt_sigreturn,syscall_restart. This is requird for moving these syscalls away from the signal frame to the vdso. Note that this patch effectively disables CONFIG_COMPAT when using clang to compile the kernel. clang doesn't support 31 bit mode. We want to redirect sigreturn and restart_syscall to the vdso. However, the kernel cannot parse the ELF vdso file, so we need to generate header files which contain the offsets of the syscall instructions in the vdso page. Signed-off-by: Sven Schnelle Reviewed-by: Heiko Carstens Signed-off-by: Vasily Gorbik

s390/vdso: always enable vdso

2021-07-08T13:37:28Z

With the upcoming move of the svc sigreturn instruction from the signal frame to vdso we need to have vdso always enabled. Signed-off-by: Sven Schnelle Reviewed-by: Heiko Carstens Signed-off-by: Vasily Gorbik

s390: convert to generic entry

2021-01-19T11:29:26Z

This patch converts s390 to use the generic entry infrastructure from kernel/entry/*. There are a few special things on s390: - PIF_PER_TRAP is moved to TIF_PER_TRAP as the generic code doesn't know about our PIF flags in exit_to_user_mode_loop(). - The old code had several ways to restart syscalls: a) PIF_SYSCALL_RESTART, which was only set during execve to force a restart after upgrading a process (usually qemu-kvm) to pgste page table extensions. b) PIF_SYSCALL, which is set by do_signal() to indicate that the current syscall should be restarted. This is changed so that do_signal() now also uses PIF_SYSCALL_RESTART. Continuing to use PIF_SYSCALL doesn't work with the generic code, and changing it to PIF_SYSCALL_RESTART makes PIF_SYSCALL and PIF_SYSCALL_RESTART more unique. - On s390 calling sys_sigreturn or sys_rt_sigreturn is implemented by executing a svc instruction on the process stack which causes a fault. While handling that fault the fault code sets PIF_SYSCALL to hand over processing to the syscall code on exit to usermode. The patch introduces PIF_SYSCALL_RET_SET, which is set if ptrace sets a return value for a syscall. The s390x ptrace ABI uses r2 both for the syscall number and return value, so ptrace cannot set the syscall number + return value at the same time. The flag makes handling that a bit easier. do_syscall() will just skip executing the syscall if PIF_SYSCALL_RET_SET is set. CONFIG_DEBUG_ASCE was removd in favour of the generic CONFIG_DEBUG_ENTRY. CR1/7/13 will be checked both on kernel entry and exit to contain the correct asces. Signed-off-by: Sven Schnelle Signed-off-by: Vasily Gorbik