Merge tag 'arc-5.10-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc

Pull ARC fixes from Vineet Gupta:
 "A couple more stack unwinder related fixes:

   - More stack unwinding updates

   - Misc minor fixes"

* tag 'arc-5.10-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc:
  ARC: stack unwinding: reorganize how initial register state setup
  ARC: stack unwinding: don't assume non-current task is sleeping
  ARC: mm: fix spelling mistakes
  ARC: bitops: Remove unecessary operation and value

Author: torvalds

arch/arc/include/asm/bitops.h

@@ -243,10 +243,8 @@ static inline int constant_fls(unsigned int x)
 		x <<= 2;
 		r -= 2;
 	}
-	if (!(x & 0x80000000u)) {
-		x <<= 1;
+	if (!(x & 0x80000000u))
 		r -= 1;
-	}
 	return r;
 }
 

arch/arc/kernel/stacktrace.c

@@ -38,15 +38,27 @@
 
 #ifdef CONFIG_ARC_DW2_UNWIND
 
-static void seed_unwind_frame_info(struct task_struct *tsk,
-				   struct pt_regs *regs,
-				   struct unwind_frame_info *frame_info)
+static int
+seed_unwind_frame_info(struct task_struct *tsk, struct pt_regs *regs,
+		       struct unwind_frame_info *frame_info)
 {
-	/*
-	 * synchronous unwinding (e.g. dump_stack)
-	 *  - uses current values of SP and friends
-	 */
-	if (tsk == NULL && regs == NULL) {
+	if (regs) {
+		/*
+		 * Asynchronous unwinding of intr/exception
+		 *  - Just uses the pt_regs passed
+		 */
+		frame_info->task = tsk;
+
+		frame_info->regs.r27 = regs->fp;
+		frame_info->regs.r28 = regs->sp;
+		frame_info->regs.r31 = regs->blink;
+		frame_info->regs.r63 = regs->ret;
+		frame_info->call_frame = 0;
+	} else if (tsk == NULL || tsk == current) {
+		/*
+		 * synchronous unwinding (e.g. dump_stack)
+		 *  - uses current values of SP and friends
+		 */
 		unsigned long fp, sp, blink, ret;
 		frame_info->task = current;
 
@@ -63,13 +75,17 @@ static void seed_unwind_frame_info(struct task_struct *tsk,
 		frame_info->regs.r31 = blink;
 		frame_info->regs.r63 = ret;
 		frame_info->call_frame = 0;
-	} else if (regs == NULL) {
+	} else {
 		/*
-		 * Asynchronous unwinding of sleeping task
-		 *  - Gets SP etc from task's pt_regs (saved bottom of kernel
-		 *    mode stack of task)
+		 * Asynchronous unwinding of a likely sleeping task
+		 *  - first ensure it is actually sleeping
+		 *  - if so, it will be in __switch_to, kernel mode SP of task
+		 *    is safe-kept and BLINK at a well known location in there
 		 */
 
+		if (tsk->state == TASK_RUNNING)
+			return -1;
+
 		frame_info->task = tsk;
 
 		frame_info->regs.r27 = TSK_K_FP(tsk);
@@ -90,19 +106,8 @@ static void seed_unwind_frame_info(struct task_struct *tsk,
 		frame_info->regs.r28 += 60;
 		frame_info->call_frame = 0;
 
-	} else {
-		/*
-		 * Asynchronous unwinding of intr/exception
-		 *  - Just uses the pt_regs passed
-		 */
-		frame_info->task = tsk;
-
-		frame_info->regs.r27 = regs->fp;
-		frame_info->regs.r28 = regs->sp;
-		frame_info->regs.r31 = regs->blink;
-		frame_info->regs.r63 = regs->ret;
-		frame_info->call_frame = 0;
 	}
+	return 0;
 }
 
 #endif
@@ -116,7 +121,8 @@ arc_unwind_core(struct task_struct *tsk, struct pt_regs *regs,
 	unsigned int address;
 	struct unwind_frame_info frame_info;
 
-	seed_unwind_frame_info(tsk, regs, &frame_info);
+	if (seed_unwind_frame_info(tsk, regs, &frame_info))
+		return 0;
 
 	while (1) {
 		address = UNW_PC(&frame_info);

arch/arc/mm/tlb.c

@@ -30,14 +30,14 @@
  *  -Changes related to MMU v2 (Rel 4.8)
  *
  * Vineetg: Aug 29th 2008
- *  -In TLB Flush operations (Metal Fix MMU) there is a explict command to
+ *  -In TLB Flush operations (Metal Fix MMU) there is a explicit command to
  *    flush Micro-TLBS. If TLB Index Reg is invalid prior to TLBIVUTLB cmd,
  *    it fails. Thus need to load it with ANY valid value before invoking
  *    TLBIVUTLB cmd
  *
  * Vineetg: Aug 21th 2008:
  *  -Reduced the duration of IRQ lockouts in TLB Flush routines
- *  -Multiple copies of TLB erase code seperated into a "single" function
+ *  -Multiple copies of TLB erase code separated into a "single" function
  *  -In TLB Flush routines, interrupt disabling moved UP to retrieve ASID
  *       in interrupt-safe region.
  *
@@ -66,7 +66,7 @@
  *
  * Although J-TLB is 2 way set assoc, ARC700 caches J-TLB into uTLBS which has
  * much higher associativity. u-D-TLB is 8 ways, u-I-TLB is 4 ways.
- * Given this, the thrasing problem should never happen because once the 3
+ * Given this, the thrashing problem should never happen because once the 3
  * J-TLB entries are created (even though 3rd will knock out one of the prev
  * two), the u-D-TLB and u-I-TLB will have what is required to accomplish memcpy
  *
@@ -127,7 +127,7 @@ static void utlb_invalidate(void)
 	 * There was however an obscure hardware bug, where uTLB flush would
 	 * fail when a prior probe for J-TLB (both totally unrelated) would
 	 * return lkup err - because the entry didn't exist in MMU.
-	 * The Workround was to set Index reg with some valid value, prior to
+	 * The Workaround was to set Index reg with some valid value, prior to
 	 * flush. This was fixed in MMU v3
 	 */
 	unsigned int idx;
@@ -272,7 +272,7 @@ noinline void local_flush_tlb_all(void)
 }
 
 /*
- * Flush the entrie MM for userland. The fastest way is to move to Next ASID
+ * Flush the entire MM for userland. The fastest way is to move to Next ASID
  */
 noinline void local_flush_tlb_mm(struct mm_struct *mm)
 {
@@ -303,7 +303,7 @@ noinline void local_flush_tlb_mm(struct mm_struct *mm)
  * Difference between this and Kernel Range Flush is
  *  -Here the fastest way (if range is too large) is to move to next ASID
  *      without doing any explicit Shootdown
- *  -In case of kernel Flush, entry has to be shot down explictly
+ *  -In case of kernel Flush, entry has to be shot down explicitly
  */
 void local_flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
 			   unsigned long end)
@@ -620,7 +620,7 @@ void update_mmu_cache(struct vm_area_struct *vma, unsigned long vaddr_unaligned,
  * Super Page size is configurable in hardware (4K to 16M), but fixed once
  * RTL builds.
  *
- * The exact THP size a Linx configuration will support is a function of:
+ * The exact THP size a Linux configuration will support is a function of:
  *  - MMU page size (typical 8K, RTL fixed)
  *  - software page walker address split between PGD:PTE:PFN (typical
  *    11:8:13, but can be changed with 1 line)
@@ -698,7 +698,7 @@ void local_flush_pmd_tlb_range(struct vm_area_struct *vma, unsigned long start,
 
 #endif
 
-/* Read the Cache Build Confuration Registers, Decode them and save into
+/* Read the Cache Build Configuration Registers, Decode them and save into
  * the cpuinfo structure for later use.
  * No Validation is done here, simply read/convert the BCRs
  */
@@ -803,13 +803,13 @@ void arc_mmu_init(void)
 	pr_info("%s", arc_mmu_mumbojumbo(0, str, sizeof(str)));
 
 	/*
-	 * Can't be done in processor.h due to header include depenedencies
+	 * Can't be done in processor.h due to header include dependencies
 	 */
 	BUILD_BUG_ON(!IS_ALIGNED((CONFIG_ARC_KVADDR_SIZE << 20), PMD_SIZE));
 
 	/*
 	 * stack top size sanity check,
-	 * Can't be done in processor.h due to header include depenedencies
+	 * Can't be done in processor.h due to header include dependencies
 	 */
 	BUILD_BUG_ON(!IS_ALIGNED(STACK_TOP, PMD_SIZE));
 
@@ -881,7 +881,7 @@ void arc_mmu_init(void)
  *      the duplicate one.
  * -Knob to be verbose abt it.(TODO: hook them up to debugfs)
  */
-volatile int dup_pd_silent; /* Be slient abt it or complain (default) */
+volatile int dup_pd_silent; /* Be silent abt it or complain (default) */
 
 void do_tlb_overlap_fault(unsigned long cause, unsigned long address,
 			  struct pt_regs *regs)
@@ -948,7 +948,7 @@ void do_tlb_overlap_fault(unsigned long cause, unsigned long address,
 
 /***********************************************************************
  * Diagnostic Routines
- *  -Called from Low Level TLB Hanlders if things don;t look good
+ *  -Called from Low Level TLB Handlers if things don;t look good
  **********************************************************************/
 
 #ifdef CONFIG_ARC_DBG_TLB_PARANOIA