Commit 56e62a73 authored by Sven Schnelle's avatar Sven Schnelle Committed by Vasily Gorbik
Browse files

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: default avatarSven Schnelle <svens@linux.ibm.com>
Signed-off-by: default avatarVasily Gorbik <gor@linux.ibm.com>
parent ac94a291

arch/s390/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -123,6 +123,7 @@ config S390 
	select GENERIC_ALLOCATOR

	select GENERIC_CPU_AUTOPROBE

	select GENERIC_CPU_VULNERABILITIES

	select GENERIC_ENTRY

	select GENERIC_FIND_FIRST_BIT

	select GENERIC_GETTIMEOFDAY

	select GENERIC_PTDUMP

arch/s390/Kconfig.debug

+6 −4
Original line number Diff line number Diff line
@@ -6,10 +6,12 @@ config TRACE_IRQFLAGS_SUPPORT 
config EARLY_PRINTK

	def_bool y



config DEBUG_USER_ASCE

	bool "Debug User ASCE"

config DEBUG_ENTRY

	bool "Debug low-level entry code"

	depends on DEBUG_KERNEL

	help

	  Check on exit to user space that address space control

	  elements are setup correctly.

	  This option enables sanity checks in s390 low-level entry code.

	  Some of these sanity checks may slow down kernel entries and

	  exits or otherwise impact performance.



	  If unsure, say N.

arch/s390/configs/debug_defconfig

+1 −1
Original line number Diff line number Diff line
@@ -833,7 +833,6 @@ CONFIG_BPF_KPROBE_OVERRIDE=y 
CONFIG_HIST_TRIGGERS=y

CONFIG_FTRACE_STARTUP_TEST=y

# CONFIG_EVENT_TRACE_STARTUP_TEST is not set

CONFIG_DEBUG_USER_ASCE=y

CONFIG_NOTIFIER_ERROR_INJECTION=m

CONFIG_NETDEV_NOTIFIER_ERROR_INJECT=m

CONFIG_FAULT_INJECTION=y
@@ -857,3 +856,4 @@ CONFIG_PERCPU_TEST=m 
CONFIG_ATOMIC64_SELFTEST=y

CONFIG_TEST_BITOPS=m

CONFIG_TEST_BPF=m

CONFIG_DEBUG_ENTRY=y

arch/s390/configs/defconfig

+0 −1
Original line number Diff line number Diff line
@@ -781,7 +781,6 @@ CONFIG_FTRACE_SYSCALLS=y 
CONFIG_BLK_DEV_IO_TRACE=y

CONFIG_BPF_KPROBE_OVERRIDE=y

CONFIG_HIST_TRIGGERS=y

CONFIG_DEBUG_USER_ASCE=y

CONFIG_LKDTM=m

CONFIG_PERCPU_TEST=m

CONFIG_ATOMIC64_SELFTEST=y

arch/s390/include/asm/cputime.h

+2 −0
Original line number Diff line number Diff line
@@ -35,4 +35,6 @@ u64 arch_cpu_idle_time(int cpu); 


#define arch_idle_time(cpu) arch_cpu_idle_time(cpu)



void account_idle_time_irq(void);



#endif /* _S390_CPUTIME_H */