xref: /linux/arch/powerpc/kernel/syscall.c (revision 114f00d738f15dd8c7318369edcdc53dd6d08763)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 
3 #include <linux/compat.h>
4 #include <linux/context_tracking.h>
5 #include <linux/entry-common.h>
6 
7 #include <asm/interrupt.h>
8 #include <asm/kup.h>
9 #include <asm/syscall.h>
10 #include <asm/time.h>
11 #include <asm/tm.h>
12 #include <asm/unistd.h>
13 
14 
15 /* Has to run notrace because it is entered not completely "reconciled" */
16 notrace long system_call_exception(struct pt_regs *regs, unsigned long r0)
17 {
18 	long ret;
19 	syscall_fn f;
20 
21 	if (unlikely(!syscall_enter_from_user_mode_randomize_stack(regs, &r0))) {
22 		clear_thread_flag(TIF_SYSCALL_RET);
23 		return syscall_get_error(current, regs);
24 	}
25 
26 	if (unlikely(test_and_clear_thread_flag(TIF_SYSCALL_RET)))
27 		return syscall_get_error(current, regs);
28 
29 	if (unlikely(r0 >= NR_syscalls)) {
30 		if (unlikely(trap_is_unsupported_scv(regs))) {
31 			/* Unsupported scv vector */
32 			_exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
33 			return regs->gpr[3];
34 		}
35 		return -ENOSYS;
36 	}
37 
38 	/* May be faster to do array_index_nospec? */
39 	barrier_nospec();
40 
41 #ifdef CONFIG_ARCH_HAS_SYSCALL_WRAPPER
42 	// No COMPAT if we have SYSCALL_WRAPPER, see Kconfig
43 	f = (void *)sys_call_table[r0];
44 	ret = f(regs);
45 #else
46 	if (unlikely(is_compat_task())) {
47 		unsigned long r3, r4, r5, r6, r7, r8;
48 
49 		f = (void *)compat_sys_call_table[r0];
50 
51 		r3 = regs->gpr[3] & 0x00000000ffffffffULL;
52 		r4 = regs->gpr[4] & 0x00000000ffffffffULL;
53 		r5 = regs->gpr[5] & 0x00000000ffffffffULL;
54 		r6 = regs->gpr[6] & 0x00000000ffffffffULL;
55 		r7 = regs->gpr[7] & 0x00000000ffffffffULL;
56 		r8 = regs->gpr[8] & 0x00000000ffffffffULL;
57 
58 		ret = f(r3, r4, r5, r6, r7, r8);
59 	} else {
60 		f = (void *)sys_call_table[r0];
61 
62 		ret = f(regs->gpr[3], regs->gpr[4], regs->gpr[5],
63 			regs->gpr[6], regs->gpr[7], regs->gpr[8]);
64 	}
65 #endif
66 
67 	return ret;
68 }
69