Commit fa191b71 authored by Ard Biesheuvel's avatar Ard Biesheuvel Committed by Russell King (Oracle)
Browse files

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: 18ed1c01 ("ARM: smp: Enable THREAD_INFO_IN_TASK")
Signed-off-by: default avatarArd Biesheuvel <ardb@kernel.org>
Signed-off-by: default avatarRussell King (Oracle) <rmk+kernel@armlinux.org.uk>
parent 13a695aa

arch/arm/include/asm/thread_info.h

+11 −0
Original line number Diff line number Diff line
@@ -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

 */

arch/arm/mm/context.c

+1 −1
Original line number Diff line number Diff line
@@ -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"