// SPDX-License-Identifier: GPL-2.0-or-later

#include <linux/compat.h>
#include <linux/context_tracking.h>
#include <linux/randomize_kstack.h>
#include <linux/entry-common.h>

#include <asm/interrupt.h>
#include <asm/kup.h>
#include <asm/syscall.h>
#include <asm/time.h>
#include <asm/tm.h>
#include <asm/unistd.h>


/* Has to run notrace because it is entered not completely "reconciled" */
notrace long system_call_exception(struct pt_regs *regs, unsigned long r0)
{
        long ret;
        syscall_fn f;

        add_random_kstack_offset();
        r0 = syscall_enter_from_user_mode(regs, r0);

        if (unlikely(r0 >= NR_syscalls)) {
                if (unlikely(trap_is_unsupported_scv(regs))) {
                        /* Unsupported scv vector */
                        _exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
                        return regs->gpr[3];
                }
                return -ENOSYS;
        }

        /* May be faster to do array_index_nospec? */
        barrier_nospec();

#ifdef CONFIG_ARCH_HAS_SYSCALL_WRAPPER
        // No COMPAT if we have SYSCALL_WRAPPER, see Kconfig
        f = (void *)sys_call_table[r0];
        ret = f(regs);
#else
        if (unlikely(is_compat_task())) {
                unsigned long r3, r4, r5, r6, r7, r8;

                f = (void *)compat_sys_call_table[r0];

                r3 = regs->gpr[3] & 0x00000000ffffffffULL;
                r4 = regs->gpr[4] & 0x00000000ffffffffULL;
                r5 = regs->gpr[5] & 0x00000000ffffffffULL;
                r6 = regs->gpr[6] & 0x00000000ffffffffULL;
                r7 = regs->gpr[7] & 0x00000000ffffffffULL;
                r8 = regs->gpr[8] & 0x00000000ffffffffULL;

                ret = f(r3, r4, r5, r6, r7, r8);
        } else {
                f = (void *)sys_call_table[r0];

                ret = f(regs->gpr[3], regs->gpr[4], regs->gpr[5],
                        regs->gpr[6], regs->gpr[7], regs->gpr[8]);
        }
#endif

        return ret;
}