ARM: 9150/1: Fix PID_IN_CONTEXTIDR regression when THREAD_INFO_IN_TASK=y

The code that implements the rarely used PID_IN_CONTEXTIDR feature
dereferences the 'task' field of struct thread_info directly, and this
is no longer possible when THREAD_INFO_IN_TASK=y, as the 'task' field is
omitted from the struct definition in that case. Instead, we should just
cast the thread_info pointer to a task_struct pointer, given that the
former is now the first member of the latter.

So use a helper that abstracts this, and provide implementations for
both cases.

Reported by: Arnd Bergmann <arnd@arndb.de>

Fixes: 18ed1c01a7 ("ARM: smp: Enable THREAD_INFO_IN_TASK")
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
This commit is contained in:
Ard Biesheuvel 2021-10-29 17:45:32 +01:00 committed by Russell King (Oracle)
parent 13a695aa50
commit fa191b711c
2 changed files with 12 additions and 1 deletions

View File

@ -79,9 +79,20 @@ struct thread_info {
#ifdef CONFIG_THREAD_INFO_IN_TASK
#define INIT_THREAD_INFO_TASK(tsk)
static inline struct task_struct *thread_task(struct thread_info* ti)
{
return (struct task_struct *)ti;
}
#else
#define INIT_THREAD_INFO_TASK(tsk) .task = &(tsk),
static inline struct task_struct *thread_task(struct thread_info* ti)
{
return ti->task;
}
/*
* how to get the thread information struct from C
*/

View File

@ -109,7 +109,7 @@ static int contextidr_notifier(struct notifier_block *unused, unsigned long cmd,
if (cmd != THREAD_NOTIFY_SWITCH)
return NOTIFY_DONE;
pid = task_pid_nr(thread->task) << ASID_BITS;
pid = task_pid_nr(thread_task(thread)) << ASID_BITS;
asm volatile(
" mrc p15, 0, %0, c13, c0, 1\n"
" and %0, %0, %2\n"