7 files changed, 34 insertions, 16 deletions
diff --git a/arch/arm/kernel/asm-offsets.c b/arch/arm/kernel/asm-offsets.c
index 645845e4982a..2c8d76fd7c66 100644
--- a/arch/arm/kernel/asm-offsets.c
+++ b/arch/arm/kernel/asm-offsets.c
@@ -43,9 +43,6 @@ int main(void)
   BLANK();
   DEFINE(TI_FLAGS,		offsetof(struct thread_info, flags));
   DEFINE(TI_PREEMPT,		offsetof(struct thread_info, preempt_count));
-#ifndef CONFIG_THREAD_INFO_IN_TASK
-  DEFINE(TI_TASK,		offsetof(struct thread_info, task));
-#endif
   DEFINE(TI_CPU,		offsetof(struct thread_info, cpu));
   DEFINE(TI_CPU_DOMAIN,		offsetof(struct thread_info, cpu_domain));
   DEFINE(TI_CPU_SAVE,		offsetof(struct thread_info, cpu_context));
diff --git a/arch/arm/kernel/entry-armv.S b/arch/arm/kernel/entry-armv.S
index 43d917f0d9a9..b58bda51e4b8 100644
--- a/arch/arm/kernel/entry-armv.S
+++ b/arch/arm/kernel/entry-armv.S
@@ -807,12 +807,13 @@ ENTRY(__switch_to)
 	switch_tls r1, r4, r5, r3, r7
 #if defined(CONFIG_STACKPROTECTOR) && !defined(CONFIG_SMP) && \
     !defined(CONFIG_STACKPROTECTOR_PER_TASK)
-	ldr	r9, [r2, #TI_TASK]
 	ldr	r8, =__stack_chk_guard
 	.if (TSK_STACK_CANARY > IMM12_MASK)
-	add	r9, r9, #TSK_STACK_CANARY & ~IMM12_MASK
-	.endif
+	add	r9, r2, #TSK_STACK_CANARY & ~IMM12_MASK
 	ldr	r9, [r9, #TSK_STACK_CANARY & IMM12_MASK]
+	.else
+	ldr	r9, [r2, #TSK_STACK_CANARY & IMM12_MASK]
+	.endif
 #endif
 	mov	r7, r2				@ Preserve 'next'
 #ifdef CONFIG_CPU_USE_DOMAINS
@@ -829,7 +830,7 @@ ENTRY(__switch_to)
 #endif
 	mov	r0, r5
 #if !defined(CONFIG_THUMB2_KERNEL) && !defined(CONFIG_VMAP_STACK)
-	set_current r7
+	set_current r7, r8
 	ldmia	r4, {r4 - sl, fp, sp, pc}	@ Load all regs saved previously
 #else
 	mov	r1, r7
@@ -851,7 +852,7 @@ ENTRY(__switch_to)
 	@ switches us to another stack, with few other side effects. In order
 	@ to prevent this distinction from causing any inconsistencies, let's
 	@ keep the 'set_current' call as close as we can to the update of SP.
-	set_current r1
+	set_current r1, r2
 	mov	sp, ip
 	ret	lr
 #endif
diff --git a/arch/arm/kernel/entry-v7m.S b/arch/arm/kernel/entry-v7m.S
index 520dd43e7e08..4e0d318b67c6 100644
--- a/arch/arm/kernel/entry-v7m.S
+++ b/arch/arm/kernel/entry-v7m.S
@@ -97,15 +97,17 @@ ENTRY(__switch_to)
 	str	sp, [ip], #4
 	str	lr, [ip], #4
 	mov	r5, r0
+	mov	r6, r2			@ Preserve 'next'
 	add	r4, r2, #TI_CPU_SAVE
 	ldr	r0, =thread_notify_head
 	mov	r1, #THREAD_NOTIFY_SWITCH
 	bl	atomic_notifier_call_chain
-	mov	ip, r4
 	mov	r0, r5
-	ldmia	ip!, {r4 - r11}		@ Load all regs saved previously
-	ldr	sp, [ip]
-	ldr	pc, [ip, #4]!
+	mov	r1, r6
+	ldmia	r4, {r4 - r12, lr}	@ Load all regs saved previously
+	set_current r1, r2
+	mov	sp, ip
+	bx	lr
 	.fnend
 ENDPROC(__switch_to)
 
diff --git a/arch/arm/kernel/head-common.S b/arch/arm/kernel/head-common.S
index da18e0a17dc2..42cae73fcc19 100644
--- a/arch/arm/kernel/head-common.S
+++ b/arch/arm/kernel/head-common.S
@@ -105,10 +105,8 @@ __mmap_switched:
 	mov	r1, #0
 	bl	__memset			@ clear .bss
 
-#ifdef CONFIG_CURRENT_POINTER_IN_TPIDRURO
 	adr_l	r0, init_task			@ get swapper task_struct
-	set_current r0
-#endif
+	set_current r0, r1
 
 	ldmia	r4, {r0, r1, r2, r3}
 	str	r9, [r0]			@ Save processor ID
diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c
index d47159f3791c..0617af11377f 100644
--- a/arch/arm/kernel/process.c
+++ b/arch/arm/kernel/process.c
@@ -36,7 +36,7 @@
 
 #include "signal.h"
 
-#ifdef CONFIG_CURRENT_POINTER_IN_TPIDRURO
+#if defined(CONFIG_CURRENT_POINTER_IN_TPIDRURO) || defined(CONFIG_SMP)
 DEFINE_PER_CPU(struct task_struct *, __entry_task);
 #endif
 
@@ -46,6 +46,11 @@ unsigned long __stack_chk_guard __read_mostly;
 EXPORT_SYMBOL(__stack_chk_guard);
 #endif
 
+#ifndef CONFIG_CURRENT_POINTER_IN_TPIDRURO
+asmlinkage struct task_struct *__current;
+EXPORT_SYMBOL(__current);
+#endif
+
 static const char *processor_modes[] __maybe_unused = {
   "USER_26", "FIQ_26" , "IRQ_26" , "SVC_26" , "UK4_26" , "UK5_26" , "UK6_26" , "UK7_26" ,
   "UK8_26" , "UK9_26" , "UK10_26", "UK11_26", "UK12_26", "UK13_26", "UK14_26", "UK15_26",
diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index 9c55ca915ba4..951559e5bea3 100644
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -403,6 +403,17 @@ static void smp_store_cpu_info(unsigned int cpuid)
 	check_cpu_icache_size(cpuid);
 }
 
+static void set_current(struct task_struct *cur)
+{
+	if (!IS_ENABLED(CONFIG_CURRENT_POINTER_IN_TPIDRURO) && !is_smp()) {
+		__current = cur;
+		return;
+	}
+
+	/* Set TPIDRURO */
+	asm("mcr p15, 0, %0, c13, c0, 3" :: "r"(cur) : "memory");
+}
+
 /*
  * This is the secondary CPU boot entry.  We're using this CPUs
  * idle thread stack, but a set of temporary page tables.
diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c
index b28a705c49cb..3f38357efc46 100644
--- a/arch/arm/kernel/traps.c
+++ b/arch/arm/kernel/traps.c
@@ -865,7 +865,9 @@ early_initcall(allocate_overflow_stacks);
 asmlinkage void handle_bad_stack(struct pt_regs *regs)
 {
 	unsigned long tsk_stk = (unsigned long)current->stack;
+#ifdef CONFIG_IRQSTACKS
 	unsigned long irq_stk = (unsigned long)this_cpu_read(irq_stack_ptr);
+#endif
 	unsigned long ovf_stk = (unsigned long)this_cpu_read(overflow_stack_ptr);
 
 	console_verbose();
@@ -873,8 +875,10 @@ asmlinkage void handle_bad_stack(struct pt_regs *regs)
 
 	pr_emerg("Task stack:     [0x%08lx..0x%08lx]\n",
 		 tsk_stk, tsk_stk + THREAD_SIZE);
+#ifdef CONFIG_IRQSTACKS
 	pr_emerg("IRQ stack:      [0x%08lx..0x%08lx]\n",
 		 irq_stk - THREAD_SIZE, irq_stk);
+#endif
 	pr_emerg("Overflow stack: [0x%08lx..0x%08lx]\n",
 		 ovf_stk - OVERFLOW_STACK_SIZE, ovf_stk);