| Mike Frysinger | e8f263d | 2010-01-26 07:33:53 +0000 | [diff] [blame] | 1 | /* |
| 2 | * Magic syscall break down functions |
| 3 | * |
| 4 | * Copyright 2010 Analog Devices Inc. |
| 5 | * |
| 6 | * Licensed under the GPL-2 or later. |
| 7 | */ |
| 8 | |
| 9 | #ifndef __ASM_BLACKFIN_SYSCALL_H__ |
| 10 | #define __ASM_BLACKFIN_SYSCALL_H__ |
| 11 | |
| 12 | /* |
| 13 | * Blackfin syscalls are simple: |
| 14 | * enter: |
| 15 | * p0: syscall number |
| 16 | * r{0,1,2,3,4,5}: syscall args 0,1,2,3,4,5 |
| 17 | * exit: |
| 18 | * r0: return/error value |
| 19 | */ |
| 20 | |
| 21 | #include <linux/err.h> |
| 22 | #include <linux/sched.h> |
| 23 | #include <asm/ptrace.h> |
| 24 | |
| 25 | static inline long |
| 26 | syscall_get_nr(struct task_struct *task, struct pt_regs *regs) |
| 27 | { |
| 28 | return regs->p0; |
| 29 | } |
| 30 | |
| 31 | static inline void |
| 32 | syscall_rollback(struct task_struct *task, struct pt_regs *regs) |
| 33 | { |
| 34 | regs->p0 = regs->orig_p0; |
| 35 | } |
| 36 | |
| 37 | static inline long |
| 38 | syscall_get_error(struct task_struct *task, struct pt_regs *regs) |
| 39 | { |
| 40 | return IS_ERR_VALUE(regs->r0) ? regs->r0 : 0; |
| 41 | } |
| 42 | |
| 43 | static inline long |
| 44 | syscall_get_return_value(struct task_struct *task, struct pt_regs *regs) |
| 45 | { |
| 46 | return regs->r0; |
| 47 | } |
| 48 | |
| 49 | static inline void |
| 50 | syscall_set_return_value(struct task_struct *task, struct pt_regs *regs, |
| 51 | int error, long val) |
| 52 | { |
| 53 | regs->r0 = error ? -error : val; |
| 54 | } |
| 55 | |
| 56 | /** |
| 57 | * syscall_get_arguments() |
| 58 | * @task: unused |
| 59 | * @regs: the register layout to extract syscall arguments from |
| 60 | * @i: first syscall argument to extract |
| 61 | * @n: number of syscall arguments to extract |
| 62 | * @args: array to return the syscall arguments in |
| 63 | * |
| 64 | * args[0] gets i'th argument, args[n - 1] gets the i+n-1'th argument |
| 65 | */ |
| 66 | static inline void |
| 67 | syscall_get_arguments(struct task_struct *task, struct pt_regs *regs, |
| 68 | unsigned int i, unsigned int n, unsigned long *args) |
| 69 | { |
| 70 | /* |
| 71 | * Assume the ptrace layout doesn't change -- r5 is first in memory, |
| 72 | * then r4, ..., then r0. So we simply reverse the ptrace register |
| 73 | * array in memory to store into the args array. |
| 74 | */ |
| 75 | long *aregs = ®s->r0 - i; |
| 76 | |
| 77 | BUG_ON(i > 5 || i + n > 6); |
| 78 | |
| 79 | while (n--) |
| 80 | *args++ = *aregs--; |
| 81 | } |
| 82 | |
| 83 | /* See syscall_get_arguments() comments */ |
| 84 | static inline void |
| 85 | syscall_set_arguments(struct task_struct *task, struct pt_regs *regs, |
| 86 | unsigned int i, unsigned int n, const unsigned long *args) |
| 87 | { |
| 88 | long *aregs = ®s->r0 - i; |
| 89 | |
| 90 | BUG_ON(i > 5 || i + n > 6); |
| 91 | |
| 92 | while (n--) |
| 93 | *aregs-- = *args++; |
| 94 | } |
| 95 | |
| 96 | #endif |