self pointer to thread info is added in thread info.
It is base change required for IRQ stack on ARM.
both stacks will have pointer to thread_info at bottom.
Co-developed-by: Vaneet Narang <[email protected]>
Signed-off-by: Vaneet Narang <[email protected]>
Signed-off-by: Maninder Singh <[email protected]>
---
arch/arm/Kconfig | 10 ++++++++++
arch/arm/include/asm/assembler.h | 3 +++
arch/arm/include/asm/thread_info.h | 27 +++++++++++++++++++++++++++
include/linux/thread_info.h | 4 ++++
kernel/fork.c | 1 +
5 files changed, 45 insertions(+)
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index fe2f17eb2..434442f 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1667,6 +1667,16 @@ config STACKPROTECTOR_PER_TASK
Enable this option to switch to a different method that uses a
different canary value for each task.
+config IRQ_STACK
+ bool "use separate stacks for Interrupts"
+ default n
+ depends on FRAME_POINTER && !CC_IS_CLANG
+ help
+ Select this option to use separate stacks for Interrupt handling code.
+ It will add latency in fetching thread info of one more derefer operation
+ and add latency in Interrupt serve at time as for each Interrupt, thread_info
+ pointer needs to be stored at bottom of interrupt stack.
+
endmenu
menu "Boot options"
diff --git a/arch/arm/include/asm/assembler.h b/arch/arm/include/asm/assembler.h
index fce52eed..8512bdc 100644
--- a/arch/arm/include/asm/assembler.h
+++ b/arch/arm/include/asm/assembler.h
@@ -207,6 +207,9 @@
THUMB( mov \rd, sp )
THUMB( lsr \rd, \rd, #THREAD_SIZE_ORDER + PAGE_SHIFT )
mov \rd, \rd, lsl #THREAD_SIZE_ORDER + PAGE_SHIFT
+#ifdef CONFIG_IRQ_STACK
+ ldr \rd, [\rd]
+#endif
.endm
/*
diff --git a/arch/arm/include/asm/thread_info.h b/arch/arm/include/asm/thread_info.h
index 536b6b9..a4d5f76 100644
--- a/arch/arm/include/asm/thread_info.h
+++ b/arch/arm/include/asm/thread_info.h
@@ -44,6 +44,9 @@ struct cpu_context_save {
* __switch_to() assumes cpu_context follows immediately after cpu_domain.
*/
struct thread_info {
+#ifdef CONFIG_IRQ_STACK
+ void *tinfo_ptr; /* pointer to self thread_info */
+#endif
unsigned long flags; /* low level flags */
int preempt_count; /* 0 => preemptable, <0 => bug */
mm_segment_t addr_limit; /* address limit */
@@ -67,14 +70,33 @@ struct thread_info {
#endif
};
+
+#ifdef CONFIG_IRQ_STACK
+#define INIT_THREAD_SELF_PTR \
+ .tinfo_ptr = &init_thread_union.thread_info,
+#else
+#define INIT_THREAD_SELF_PTR
+#endif
+
#define INIT_THREAD_INFO(tsk) \
{ \
+ INIT_THREAD_SELF_PTR \
.task = &tsk, \
.flags = 0, \
.preempt_count = INIT_PREEMPT_COUNT, \
.addr_limit = KERNEL_DS, \
}
+
+#ifdef CONFIG_IRQ_STACK
+#define TASK_THREAD_SELF_POINTER(tsk) \
+{ \
+ struct thread_info *ti = task_thread_info(tsk); \
+ \
+ ti->tinfo_ptr = ti; \
+}
+#endif
+
/*
* how to get the thread information struct from C
*/
@@ -82,8 +104,13 @@ struct thread_info {
static inline struct thread_info *current_thread_info(void)
{
+#ifdef CONFIG_IRQ_STACK
+ return (struct thread_info *)
+ (*((unsigned long *)(current_stack_pointer & ~(THREAD_SIZE - 1))));
+#else
return (struct thread_info *)
(current_stack_pointer & ~(THREAD_SIZE - 1));
+#endif
}
#define thread_saved_pc(tsk) \
diff --git a/include/linux/thread_info.h b/include/linux/thread_info.h
index e93e249..ddf7b43 100644
--- a/include/linux/thread_info.h
+++ b/include/linux/thread_info.h
@@ -43,6 +43,10 @@ enum {
#define THREAD_ALIGN THREAD_SIZE
#endif
+#ifndef TASK_THREAD_SELF_POINTER
+#define TASK_THREAD_SELF_POINTER(tsk)
+#endif
+
#define THREADINFO_GFP (GFP_KERNEL_ACCOUNT | __GFP_ZERO)
/*
diff --git a/kernel/fork.c b/kernel/fork.c
index 7ef3eb3..d53f5eb 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -901,6 +901,7 @@ static struct task_struct *dup_task_struct(struct task_struct *orig, int node)
#endif
setup_thread_stack(tsk, orig);
+ TASK_THREAD_SELF_POINTER(tsk);
clear_user_return_notifier(tsk);
clear_tsk_need_resched(tsk);
set_task_stack_end_magic(tsk);
--
1.9.1