mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-11-24 02:24:28 +08:00
2f064a59a1
Change the type and name of task_struct::state. Drop the volatile and shrink it to an 'unsigned int'. Rename it in order to find all uses such that we can use READ_ONCE/WRITE_ONCE as appropriate. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Daniel Bristot de Oliveira <bristot@redhat.com> Acked-by: Will Deacon <will@kernel.org> Acked-by: Daniel Thompson <daniel.thompson@linaro.org> Link: https://lore.kernel.org/r/20210611082838.550736351@infradead.org
89 lines
2.7 KiB
C
89 lines
2.7 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
#include <linux/ptrace.h>
|
|
#include <linux/sched.h>
|
|
#include <linux/sched/task_stack.h>
|
|
#include <linux/export.h>
|
|
#include <asm/syscall.h>
|
|
|
|
static int collect_syscall(struct task_struct *target, struct syscall_info *info)
|
|
{
|
|
unsigned long args[6] = { };
|
|
struct pt_regs *regs;
|
|
|
|
if (!try_get_task_stack(target)) {
|
|
/* Task has no stack, so the task isn't in a syscall. */
|
|
memset(info, 0, sizeof(*info));
|
|
info->data.nr = -1;
|
|
return 0;
|
|
}
|
|
|
|
regs = task_pt_regs(target);
|
|
if (unlikely(!regs)) {
|
|
put_task_stack(target);
|
|
return -EAGAIN;
|
|
}
|
|
|
|
info->sp = user_stack_pointer(regs);
|
|
info->data.instruction_pointer = instruction_pointer(regs);
|
|
|
|
info->data.nr = syscall_get_nr(target, regs);
|
|
if (info->data.nr != -1L)
|
|
syscall_get_arguments(target, regs, args);
|
|
|
|
info->data.args[0] = args[0];
|
|
info->data.args[1] = args[1];
|
|
info->data.args[2] = args[2];
|
|
info->data.args[3] = args[3];
|
|
info->data.args[4] = args[4];
|
|
info->data.args[5] = args[5];
|
|
|
|
put_task_stack(target);
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* task_current_syscall - Discover what a blocked task is doing.
|
|
* @target: thread to examine
|
|
* @info: structure with the following fields:
|
|
* .sp - filled with user stack pointer
|
|
* .data.nr - filled with system call number or -1
|
|
* .data.args - filled with @maxargs system call arguments
|
|
* .data.instruction_pointer - filled with user PC
|
|
*
|
|
* If @target is blocked in a system call, returns zero with @info.data.nr
|
|
* set to the call's number and @info.data.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 *@info.data.nr set to -1 and does not fill in
|
|
* @info.data.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.
|
|
*/
|
|
int task_current_syscall(struct task_struct *target, struct syscall_info *info)
|
|
{
|
|
unsigned long ncsw;
|
|
unsigned int state;
|
|
|
|
if (target == current)
|
|
return collect_syscall(target, info);
|
|
|
|
state = READ_ONCE(target->__state);
|
|
if (unlikely(!state))
|
|
return -EAGAIN;
|
|
|
|
ncsw = wait_task_inactive(target, state);
|
|
if (unlikely(!ncsw) ||
|
|
unlikely(collect_syscall(target, info)) ||
|
|
unlikely(wait_task_inactive(target, state) != ncsw))
|
|
return -EAGAIN;
|
|
|
|
return 0;
|
|
}
|