mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-23 12:43:55 +08:00
76 lines
2.4 KiB
C
76 lines
2.4 KiB
C
|
#include <linux/ptrace.h>
|
||
|
|
#include <linux/sched.h>
|
||
|
|
#include <linux/module.h>
|
||
|
|
#include <asm/syscall.h>
|
||
|
|
|
||
|
|
static int collect_syscall(struct task_struct *target, long *callno,
|
||
|
|
unsigned long args[6], unsigned int maxargs,
|
||
|
|
unsigned long *sp, unsigned long *pc)
|
||
|
|
{
|
||
|
|
struct pt_regs *regs = task_pt_regs(target);
|
||
|
|
if (unlikely(!regs))
|
||
|
|
return -EAGAIN;
|
||
|
|
|
||
|
|
*sp = user_stack_pointer(regs);
|
||
|
|
*pc = instruction_pointer(regs);
|
||
|
|
|
||
|
|
*callno = syscall_get_nr(target, regs);
|
||
|
|
if (*callno != -1L && maxargs > 0)
|
||
|
|
syscall_get_arguments(target, regs, 0, maxargs, args);
|
||
|
|
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* task_current_syscall - Discover what a blocked task is doing.
|
||
|
|
* @target: thread to examine
|
||
|
|
* @callno: filled with system call number or -1
|
||
|
|
* @args: filled with @maxargs system call arguments
|
||
|
|
* @maxargs: number of elements in @args to fill
|
||
|
|
* @sp: filled with user stack pointer
|
||
|
|
* @pc: filled with user PC
|
||
|
|
*
|
||
|
|
* If @target is blocked in a system call, returns zero with *@callno
|
||
|
|
* set to the the call's number and @args filled in with its arguments.
|
||
|
|
* Registers not used for system call arguments may not be available and
|
||
|
|
* it is not kosher to use &struct user_regset calls while the system
|
||
|
|
* call is still in progress. Note we may get this result if @target
|
||
|
|
* has finished its system call but not yet returned to user mode, such
|
||
|
|
* as when it's stopped for signal handling or syscall exit tracing.
|
||
|
|
*
|
||
|
|
* If @target is blocked in the kernel during a fault or exception,
|
||
|
|
* returns zero with *@callno set to -1 and does not fill in @args.
|
||
|
|
* If so, it's now safe to examine @target using &struct user_regset
|
||
|
|
* get() calls as long as we're sure @target won't return to user mode.
|
||
|
|
*
|
||
|
|
* Returns -%EAGAIN if @target does not remain blocked.
|
||
|
|
*
|
||
|
|
* Returns -%EINVAL if @maxargs is too large (maximum is six).
|
||
|
|
*/
|
||
|
|
int task_current_syscall(struct task_struct *target, long *callno,
|
||
|
|
unsigned long args[6], unsigned int maxargs,
|
||
|
|
unsigned long *sp, unsigned long *pc)
|
||
|
|
{
|
||
|
|
long state;
|
||
|
|
unsigned long ncsw;
|
||
|
|
|
||
|
|
if (unlikely(maxargs > 6))
|
||
|
|
return -EINVAL;
|
||
|
|
|
||
|
|
if (target == current)
|
||
|
|
return collect_syscall(target, callno, args, maxargs, sp, pc);
|
||
|
|
|
||
|
|
state = target->state;
|
||
|
|
if (unlikely(!state))
|
||
|
|
return -EAGAIN;
|
||
|
|
|
||
|
|
ncsw = wait_task_inactive(target, state);
|
||
|
|
if (unlikely(!ncsw) ||
|
||
|
|
unlikely(collect_syscall(target, callno, args, maxargs, sp, pc)) ||
|
||
|
|
unlikely(wait_task_inactive(target, state) != ncsw))
|
||
|
|
return -EAGAIN;
|
||
|
|
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
EXPORT_SYMBOL_GPL(task_current_syscall);
|