microblaze: Add support from PREEMPT
This patch add core PREEMPT support for Microblaze.
I tried to trace it via tracers and I was able to see any output.
I also added low level debug functions to see if that code is called.
Signed-off-by: Michal Simek <monstr@monstr.eu>
diff --git a/arch/microblaze/include/asm/tlbflush.h b/arch/microblaze/include/asm/tlbflush.h
index 10ec70c..bcb8b41 100644
--- a/arch/microblaze/include/asm/tlbflush.h
+++ b/arch/microblaze/include/asm/tlbflush.h
@@ -23,7 +23,7 @@
extern void _tlbie(unsigned long address);
extern void _tlbia(void);
-#define __tlbia() _tlbia()
+#define __tlbia() { preempt_disable(); _tlbia(); preempt_enable(); }
static inline void local_flush_tlb_all(void)
{ __tlbia(); }
diff --git a/arch/microblaze/kernel/asm-offsets.c b/arch/microblaze/kernel/asm-offsets.c
index 7bc7b68..0071260 100644
--- a/arch/microblaze/kernel/asm-offsets.c
+++ b/arch/microblaze/kernel/asm-offsets.c
@@ -90,6 +90,7 @@
DEFINE(TI_FLAGS, offsetof(struct thread_info, flags));
DEFINE(TI_ADDR_LIMIT, offsetof(struct thread_info, addr_limit));
DEFINE(TI_CPU_CONTEXT, offsetof(struct thread_info, cpu_context));
+ DEFINE(TI_PREEMPT_COUNT, offsetof(struct thread_info, preempt_count));
BLANK();
/* struct cpu_context */
diff --git a/arch/microblaze/kernel/entry.S b/arch/microblaze/kernel/entry.S
index 3bad4ff..1a6729d 100644
--- a/arch/microblaze/kernel/entry.S
+++ b/arch/microblaze/kernel/entry.S
@@ -853,7 +853,30 @@
lwi r1, r1, PT_R1 - PT_SIZE;
bri 6f;
/* MS: Return to kernel state. */
-2: VM_OFF /* MS: turn off MMU */
+2:
+#ifdef CONFIG_PREEMPT
+ add r11, r0, CURRENT_TASK;
+ lwi r11, r11, TS_THREAD_INFO;
+ /* MS: get preempt_count from thread info */
+ lwi r5, r11, TI_PREEMPT_COUNT;
+ bgti r5, restore;
+
+ lwi r5, r11, TI_FLAGS; /* get flags in thread info */
+ andi r5, r5, _TIF_NEED_RESCHED;
+ beqi r5, restore /* if zero jump over */
+
+preempt:
+ /* interrupts are off that's why I am calling preempt_chedule_irq */
+ bralid r15, preempt_schedule_irq
+ nop
+ add r11, r0, CURRENT_TASK; /* Get current task ptr into r11 */
+ lwi r11, r11, TS_THREAD_INFO; /* get thread info */
+ lwi r5, r11, TI_FLAGS; /* get flags in thread info */
+ andi r5, r5, _TIF_NEED_RESCHED;
+ bnei r5, preempt /* if non zero jump to resched */
+restore:
+#endif
+ VM_OFF /* MS: turn off MMU */
tophys(r1,r1)
lwi r3, r1, PTO + PT_R3; /* MS: restore saved r3, r4 registers */
lwi r4, r1, PTO + PT_R4;