xref: /linux/arch/powerpc/kernel/syscall.c (revision bba2c3615bd6cfee7456d1130f2e6b01b3f4e9ba)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 
3 #include <linux/compat.h>
4 #include <linux/context_tracking.h>
5 #include <linux/randomize_kstack.h>
6 #include <linux/entry-common.h>
7 
8 #include <asm/interrupt.h>
9 #include <asm/kup.h>
10 #include <asm/syscall.h>
11 #include <asm/time.h>
12 #include <asm/tm.h>
13 #include <asm/unistd.h>
14 
15 
16 /* Has to run notrace because it is entered not completely "reconciled" */
17 notrace long system_call_exception(struct pt_regs *regs, unsigned long r0)
18 {
19 	long ret;
20 	syscall_fn f;
21 
22 	add_random_kstack_offset();
23 	r0 = syscall_enter_from_user_mode(regs, r0);
24 
25 	if (unlikely(r0 >= NR_syscalls)) {
26 		if (unlikely(trap_is_unsupported_scv(regs))) {
27 			/* Unsupported scv vector */
28 			_exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
29 			return regs->gpr[3];
30 		}
31 		return -ENOSYS;
32 	}
33 
34 	/* May be faster to do array_index_nospec? */
35 	barrier_nospec();
36 
37 #ifdef CONFIG_ARCH_HAS_SYSCALL_WRAPPER
38 	// No COMPAT if we have SYSCALL_WRAPPER, see Kconfig
39 	f = (void *)sys_call_table[r0];
40 	ret = f(regs);
41 #else
42 	if (unlikely(is_compat_task())) {
43 		unsigned long r3, r4, r5, r6, r7, r8;
44 
45 		f = (void *)compat_sys_call_table[r0];
46 
47 		r3 = regs->gpr[3] & 0x00000000ffffffffULL;
48 		r4 = regs->gpr[4] & 0x00000000ffffffffULL;
49 		r5 = regs->gpr[5] & 0x00000000ffffffffULL;
50 		r6 = regs->gpr[6] & 0x00000000ffffffffULL;
51 		r7 = regs->gpr[7] & 0x00000000ffffffffULL;
52 		r8 = regs->gpr[8] & 0x00000000ffffffffULL;
53 
54 		ret = f(r3, r4, r5, r6, r7, r8);
55 	} else {
56 		f = (void *)sys_call_table[r0];
57 
58 		ret = f(regs->gpr[3], regs->gpr[4], regs->gpr[5],
59 			regs->gpr[6], regs->gpr[7], regs->gpr[8]);
60 	}
61 #endif
62 
63 	return ret;
64 }
65