From 56e62a73702836017564eaacd5212e4d0fa1c01d Mon Sep 17 00:00:00 2001 From: Sven Schnelle Date: Sat, 21 Nov 2020 11:14:56 +0100 Subject: s390: convert to generic entry 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 --- arch/s390/kernel/nmi.c | 19 ++++++++++++------- 1 file changed, 12 insertions(+), 7 deletions(-) (limited to 'arch/s390/kernel/nmi.c') diff --git a/arch/s390/kernel/nmi.c b/arch/s390/kernel/nmi.c index 86c8d5370e7f..11f8c296f60d 100644 --- a/arch/s390/kernel/nmi.c +++ b/arch/s390/kernel/nmi.c @@ -131,12 +131,11 @@ static notrace void s390_handle_damage(void) NOKPROBE_SYMBOL(s390_handle_damage); /* - * Main machine check handler function. Will be called with interrupts enabled - * or disabled and machine checks enabled or disabled. + * Main machine check handler function. Will be called with interrupts disabled + * and machine checks enabled. */ -void s390_handle_mcck(void) +void __s390_handle_mcck(void) { - unsigned long flags; struct mcck_struct mcck; /* @@ -144,12 +143,10 @@ void s390_handle_mcck(void) * machine checks. Afterwards delete the old state and enable machine * checks again. */ - local_irq_save(flags); local_mcck_disable(); mcck = *this_cpu_ptr(&cpu_mcck); memset(this_cpu_ptr(&cpu_mcck), 0, sizeof(mcck)); local_mcck_enable(); - local_irq_restore(flags); if (mcck.channel_report) crw_handle_channel_report(); @@ -181,8 +178,13 @@ void s390_handle_mcck(void) do_exit(SIGSEGV); } } -EXPORT_SYMBOL_GPL(s390_handle_mcck); +void noinstr s390_handle_mcck(void) +{ + trace_hardirqs_off(); + __s390_handle_mcck(); + trace_hardirqs_on(); +} /* * returns 0 if all required registers are available * returns 1 otherwise @@ -344,6 +346,9 @@ int notrace s390_do_machine_check(struct pt_regs *regs) int mcck_pending = 0; nmi_enter(); + + if (user_mode(regs)) + update_timer_mcck(); inc_irq_stat(NMI_NMI); mci.val = S390_lowcore.mcck_interruption_code; mcck = this_cpu_ptr(&cpu_mcck); -- cgit v1.2.3-59-g8ed1b