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56e62a7370
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 <svens@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
61 lines
1.4 KiB
C
61 lines
1.4 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef ARCH_S390_ENTRY_COMMON_H
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#define ARCH_S390_ENTRY_COMMON_H
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#include <linux/sched.h>
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#include <linux/audit.h>
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#include <linux/tracehook.h>
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#include <linux/processor.h>
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#include <linux/uaccess.h>
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#include <asm/fpu/api.h>
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#define ARCH_EXIT_TO_USER_MODE_WORK (_TIF_GUARDED_STORAGE | _TIF_PER_TRAP)
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void do_per_trap(struct pt_regs *regs);
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void do_syscall(struct pt_regs *regs);
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typedef void (*pgm_check_func)(struct pt_regs *regs);
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extern pgm_check_func pgm_check_table[128];
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#ifdef CONFIG_DEBUG_ENTRY
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static __always_inline void arch_check_user_regs(struct pt_regs *regs)
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{
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debug_user_asce(0);
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}
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#define arch_check_user_regs arch_check_user_regs
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#endif /* CONFIG_DEBUG_ENTRY */
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static __always_inline void arch_exit_to_user_mode_work(struct pt_regs *regs,
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unsigned long ti_work)
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{
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if (ti_work & _TIF_PER_TRAP) {
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clear_thread_flag(TIF_PER_TRAP);
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do_per_trap(regs);
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}
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if (ti_work & _TIF_GUARDED_STORAGE)
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gs_load_bc_cb(regs);
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}
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#define arch_exit_to_user_mode_work arch_exit_to_user_mode_work
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static __always_inline void arch_exit_to_user_mode(void)
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{
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if (test_cpu_flag(CIF_FPU))
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__load_fpu_regs();
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if (IS_ENABLED(CONFIG_DEBUG_ENTRY))
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debug_user_asce(1);
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}
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#define arch_exit_to_user_mode arch_exit_to_user_mode
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static inline bool on_thread_stack(void)
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{
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return !(((unsigned long)(current->stack) ^ current_stack_pointer()) & ~(THREAD_SIZE - 1));
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}
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#endif
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