linux/arch/m68k/include/asm/thread_info.h
Michael Schmitz 6baaade155 m68k: Add kernel seccomp support
Add secure_computing() call to syscall_trace_enter to actually
filter system calls.

Add necessary arch Kconfig options, define TIF_SECCOMP trace
flag and provide basic seccomp filter support in asm/syscall.h

syscall_get_nr currently uses the syscall nr stored in orig_d0
because we change d0 to a default return code before starting a
syscall trace. This may be inconsistent with syscall_rollback
copying orig_d0 to d0 (which we never check upon return from
trace). We use d0 for the return code from syscall_trace_enter
in entry.S currently, and could perhaps expand that to store
a new syscall number returned by the seccomp filter before
executing the syscall. This clearly needs some discussion.

seccomp_bpf self test on ARAnyM passes 81 out of 94 tests.

Signed-off-by: Michael Schmitz <schmitzmic@gmail.com>
Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
Link: https://lore.kernel.org/r/20230112035529.13521-3-schmitzmic@gmail.com
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
2023-01-30 16:40:15 +01:00

80 lines
2.3 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ASM_M68K_THREAD_INFO_H
#define _ASM_M68K_THREAD_INFO_H
#include <asm/types.h>
#include <asm/page.h>
/*
* On machines with 4k pages we default to an 8k thread size, though we
* allow a 4k with config option. Any other machine page size then
* the thread size must match the page size (which is 8k and larger here).
*/
#if PAGE_SHIFT < 13
#ifdef CONFIG_4KSTACKS
#define THREAD_SIZE 4096
#else
#define THREAD_SIZE 8192
#endif
#else
#define THREAD_SIZE PAGE_SIZE
#endif
#define THREAD_SIZE_ORDER ((THREAD_SIZE / PAGE_SIZE) - 1)
#ifndef __ASSEMBLY__
struct thread_info {
struct task_struct *task; /* main task structure */
unsigned long flags;
int preempt_count; /* 0 => preemptable, <0 => BUG */
__u32 cpu; /* should always be 0 on m68k */
unsigned long tp_value; /* thread pointer */
};
#endif /* __ASSEMBLY__ */
#define INIT_THREAD_INFO(tsk) \
{ \
.task = &tsk, \
.preempt_count = INIT_PREEMPT_COUNT, \
}
#ifndef __ASSEMBLY__
/* how to get the thread information struct from C */
static inline struct thread_info *current_thread_info(void)
{
struct thread_info *ti;
__asm__(
"move.l %%sp, %0 \n\t"
"and.l %1, %0"
: "=&d"(ti)
: "di" (~(THREAD_SIZE-1))
);
return ti;
}
#endif
/* entry.S relies on these definitions!
* bits 0-7 are tested at every exception exit
* bits 8-15 are also tested at syscall exit
*/
#define TIF_NOTIFY_SIGNAL 4
#define TIF_NOTIFY_RESUME 5 /* callback before returning to user */
#define TIF_SIGPENDING 6 /* signal pending */
#define TIF_NEED_RESCHED 7 /* rescheduling necessary */
#define TIF_SECCOMP 13 /* seccomp syscall filtering active */
#define TIF_DELAYED_TRACE 14 /* single step a syscall */
#define TIF_SYSCALL_TRACE 15 /* syscall trace active */
#define TIF_MEMDIE 16 /* is terminating due to OOM killer */
#define TIF_RESTORE_SIGMASK 18 /* restore signal mask in do_signal */
#define _TIF_NOTIFY_RESUME (1 << TIF_NOTIFY_RESUME)
#define _TIF_SIGPENDING (1 << TIF_SIGPENDING)
#define _TIF_NEED_RESCHED (1 << TIF_NEED_RESCHED)
#define _TIF_SECCOMP (1 << TIF_SECCOMP)
#define _TIF_DELAYED_TRACE (1 << TIF_DELAYED_TRACE)
#define _TIF_SYSCALL_TRACE (1 << TIF_SYSCALL_TRACE)
#define _TIF_MEMDIE (1 << TIF_MEMDIE)
#define _TIF_RESTORE_SIGMASK (1 << TIF_RESTORE_SIGMASK)
#endif /* _ASM_M68K_THREAD_INFO_H */