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author | Sven Schnelle <svens@linux.ibm.com> | 2020-11-21 13:14:56 +0300 |
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committer | Vasily Gorbik <gor@linux.ibm.com> | 2021-01-19 14:29:26 +0300 |
commit | 56e62a73702836017564eaacd5212e4d0fa1c01d (patch) | |
tree | f99a6cb9175ddddc37f36ad538555fbb5c606a6c /arch/s390/include/asm/entry-common.h | |
parent | ac94a2911e84a7b3d29d725f8f43b07db1c916f2 (diff) | |
download | linux-56e62a73702836017564eaacd5212e4d0fa1c01d.tar.xz |
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 <svens@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Diffstat (limited to 'arch/s390/include/asm/entry-common.h')
-rw-r--r-- | arch/s390/include/asm/entry-common.h | 60 |
1 files changed, 60 insertions, 0 deletions
diff --git a/arch/s390/include/asm/entry-common.h b/arch/s390/include/asm/entry-common.h new file mode 100644 index 000000000000..75cebc80474e --- /dev/null +++ b/arch/s390/include/asm/entry-common.h @@ -0,0 +1,60 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef ARCH_S390_ENTRY_COMMON_H +#define ARCH_S390_ENTRY_COMMON_H + +#include <linux/sched.h> +#include <linux/audit.h> +#include <linux/tracehook.h> +#include <linux/processor.h> +#include <linux/uaccess.h> +#include <asm/fpu/api.h> + +#define ARCH_EXIT_TO_USER_MODE_WORK (_TIF_GUARDED_STORAGE | _TIF_PER_TRAP) + +void do_per_trap(struct pt_regs *regs); +void do_syscall(struct pt_regs *regs); + +typedef void (*pgm_check_func)(struct pt_regs *regs); + +extern pgm_check_func pgm_check_table[128]; + +#ifdef CONFIG_DEBUG_ENTRY +static __always_inline void arch_check_user_regs(struct pt_regs *regs) +{ + debug_user_asce(0); +} + +#define arch_check_user_regs arch_check_user_regs +#endif /* CONFIG_DEBUG_ENTRY */ + +static __always_inline void arch_exit_to_user_mode_work(struct pt_regs *regs, + unsigned long ti_work) +{ + if (ti_work & _TIF_PER_TRAP) { + clear_thread_flag(TIF_PER_TRAP); + do_per_trap(regs); + } + + if (ti_work & _TIF_GUARDED_STORAGE) + gs_load_bc_cb(regs); +} + +#define arch_exit_to_user_mode_work arch_exit_to_user_mode_work + +static __always_inline void arch_exit_to_user_mode(void) +{ + if (test_cpu_flag(CIF_FPU)) + __load_fpu_regs(); + + if (IS_ENABLED(CONFIG_DEBUG_ENTRY)) + debug_user_asce(1); +} + +#define arch_exit_to_user_mode arch_exit_to_user_mode + +static inline bool on_thread_stack(void) +{ + return !(((unsigned long)(current->stack) ^ current_stack_pointer()) & ~(THREAD_SIZE - 1)); +} + +#endif |