diff options
Diffstat (limited to 'lib/syscall.c')
-rw-r--r-- | lib/syscall.c | 57 |
1 files changed, 25 insertions, 32 deletions
diff --git a/lib/syscall.c b/lib/syscall.c index 1a7077f20eae..fb328e7ccb08 100644 --- a/lib/syscall.c +++ b/lib/syscall.c | |||
@@ -5,16 +5,14 @@ | |||
5 | #include <linux/export.h> | 5 | #include <linux/export.h> |
6 | #include <asm/syscall.h> | 6 | #include <asm/syscall.h> |
7 | 7 | ||
8 | static int collect_syscall(struct task_struct *target, long *callno, | 8 | static int collect_syscall(struct task_struct *target, struct syscall_info *info) |
9 | unsigned long args[6], unsigned int maxargs, | ||
10 | unsigned long *sp, unsigned long *pc) | ||
11 | { | 9 | { |
12 | struct pt_regs *regs; | 10 | struct pt_regs *regs; |
13 | 11 | ||
14 | if (!try_get_task_stack(target)) { | 12 | if (!try_get_task_stack(target)) { |
15 | /* Task has no stack, so the task isn't in a syscall. */ | 13 | /* Task has no stack, so the task isn't in a syscall. */ |
16 | *sp = *pc = 0; | 14 | memset(info, 0, sizeof(*info)); |
17 | *callno = -1; | 15 | info->data.nr = -1; |
18 | return 0; | 16 | return 0; |
19 | } | 17 | } |
20 | 18 | ||
@@ -24,12 +22,13 @@ static int collect_syscall(struct task_struct *target, long *callno, | |||
24 | return -EAGAIN; | 22 | return -EAGAIN; |
25 | } | 23 | } |
26 | 24 | ||
27 | *sp = user_stack_pointer(regs); | 25 | info->sp = user_stack_pointer(regs); |
28 | *pc = instruction_pointer(regs); | 26 | info->data.instruction_pointer = instruction_pointer(regs); |
29 | 27 | ||
30 | *callno = syscall_get_nr(target, regs); | 28 | info->data.nr = syscall_get_nr(target, regs); |
31 | if (*callno != -1L && maxargs > 0) | 29 | if (info->data.nr != -1L) |
32 | syscall_get_arguments(target, regs, 0, maxargs, args); | 30 | syscall_get_arguments(target, regs, |
31 | (unsigned long *)&info->data.args[0]); | ||
33 | 32 | ||
34 | put_task_stack(target); | 33 | put_task_stack(target); |
35 | return 0; | 34 | return 0; |
@@ -38,41 +37,35 @@ static int collect_syscall(struct task_struct *target, long *callno, | |||
38 | /** | 37 | /** |
39 | * task_current_syscall - Discover what a blocked task is doing. | 38 | * task_current_syscall - Discover what a blocked task is doing. |
40 | * @target: thread to examine | 39 | * @target: thread to examine |
41 | * @callno: filled with system call number or -1 | 40 | * @info: structure with the following fields: |
42 | * @args: filled with @maxargs system call arguments | 41 | * .sp - filled with user stack pointer |
43 | * @maxargs: number of elements in @args to fill | 42 | * .data.nr - filled with system call number or -1 |
44 | * @sp: filled with user stack pointer | 43 | * .data.args - filled with @maxargs system call arguments |
45 | * @pc: filled with user PC | 44 | * .data.instruction_pointer - filled with user PC |
46 | * | 45 | * |
47 | * If @target is blocked in a system call, returns zero with *@callno | 46 | * If @target is blocked in a system call, returns zero with @info.data.nr |
48 | * set to the the call's number and @args filled in with its arguments. | 47 | * set to the the call's number and @info.data.args filled in with its |
49 | * Registers not used for system call arguments may not be available and | 48 | * arguments. Registers not used for system call arguments may not be available |
50 | * it is not kosher to use &struct user_regset calls while the system | 49 | * and it is not kosher to use &struct user_regset calls while the system |
51 | * call is still in progress. Note we may get this result if @target | 50 | * call is still in progress. Note we may get this result if @target |
52 | * has finished its system call but not yet returned to user mode, such | 51 | * has finished its system call but not yet returned to user mode, such |
53 | * as when it's stopped for signal handling or syscall exit tracing. | 52 | * as when it's stopped for signal handling or syscall exit tracing. |
54 | * | 53 | * |
55 | * If @target is blocked in the kernel during a fault or exception, | 54 | * If @target is blocked in the kernel during a fault or exception, |
56 | * returns zero with *@callno set to -1 and does not fill in @args. | 55 | * returns zero with *@info.data.nr set to -1 and does not fill in |
57 | * If so, it's now safe to examine @target using &struct user_regset | 56 | * @info.data.args. If so, it's now safe to examine @target using |
58 | * get() calls as long as we're sure @target won't return to user mode. | 57 | * &struct user_regset get() calls as long as we're sure @target won't return |
58 | * to user mode. | ||
59 | * | 59 | * |
60 | * Returns -%EAGAIN if @target does not remain blocked. | 60 | * Returns -%EAGAIN if @target does not remain blocked. |
61 | * | ||
62 | * Returns -%EINVAL if @maxargs is too large (maximum is six). | ||
63 | */ | 61 | */ |
64 | int task_current_syscall(struct task_struct *target, long *callno, | 62 | int task_current_syscall(struct task_struct *target, struct syscall_info *info) |
65 | unsigned long args[6], unsigned int maxargs, | ||
66 | unsigned long *sp, unsigned long *pc) | ||
67 | { | 63 | { |
68 | long state; | 64 | long state; |
69 | unsigned long ncsw; | 65 | unsigned long ncsw; |
70 | 66 | ||
71 | if (unlikely(maxargs > 6)) | ||
72 | return -EINVAL; | ||
73 | |||
74 | if (target == current) | 67 | if (target == current) |
75 | return collect_syscall(target, callno, args, maxargs, sp, pc); | 68 | return collect_syscall(target, info); |
76 | 69 | ||
77 | state = target->state; | 70 | state = target->state; |
78 | if (unlikely(!state)) | 71 | if (unlikely(!state)) |
@@ -80,7 +73,7 @@ int task_current_syscall(struct task_struct *target, long *callno, | |||
80 | 73 | ||
81 | ncsw = wait_task_inactive(target, state); | 74 | ncsw = wait_task_inactive(target, state); |
82 | if (unlikely(!ncsw) || | 75 | if (unlikely(!ncsw) || |
83 | unlikely(collect_syscall(target, callno, args, maxargs, sp, pc)) || | 76 | unlikely(collect_syscall(target, info)) || |
84 | unlikely(wait_task_inactive(target, state) != ncsw)) | 77 | unlikely(wait_task_inactive(target, state) != ncsw)) |
85 | return -EAGAIN; | 78 | return -EAGAIN; |
86 | 79 | ||