From fa191b711c32ba107cf8d3474cd860407b7e997a Mon Sep 17 00:00:00 2001
From: Ard Biesheuvel <ardb@kernel.org>
Date: Fri, 29 Oct 2021 17:45:32 +0100
Subject: [PATCH] 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: 18ed1c01a7dd ("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>
---
arch/arm/include/asm/thread_info.h | 11 +++++++++++
arch/arm/mm/context.c | 2 +-
2 files changed, 12 insertions(+), 1 deletion(-)
diff --git a/arch/arm/include/asm/thread_info.h b/arch/arm/include/asm/thread_info.h
index 787511396f3f4..164e15f26485d 100644
--- a/arch/arm/include/asm/thread_info.h
+++ b/arch/arm/include/asm/thread_info.h
@@ -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
*/
diff --git a/arch/arm/mm/context.c b/arch/arm/mm/context.c
index b7525b433f3e2..48091870db89e 100644
--- a/arch/arm/mm/context.c
+++ b/arch/arm/mm/context.c
@@ -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"