Merge tag 'arc-5.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc

Pull ARC updates from Vineet Gupta:

 - long due rewrite of do_page_fault

 - refactoring of entry/exit code to utilize the double load/store
   instructions

 - hsdk platform updates

* tag 'arc-5.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc:
  ARC: [plat-hsdk]: Enable AXI DW DMAC in defconfig
  ARC: [plat-hsdk]: enable DW SPI controller
  ARC: hide unused function unw_hdr_alloc
  ARC: [haps] Add Virtio support
  ARCv2: entry: simplify return to Delay Slot via interrupt
  ARC: entry: EV_Trap expects r10 (vs. r9) to have exception cause
  ARCv2: entry: rewrite to enable use of double load/stores LDD/STD
  ARCv2: entry: avoid a branch
  ARCv2: entry: push out the Z flag unclobber from common EXCEPTION_PROLOGUE
  ARCv2: entry: comments about hardware auto-save on taken interrupts
  ARC: mm: do_page_fault refactor #8: release mmap_sem sooner
  ARC: mm: do_page_fault refactor #7: fold the various error handling
  ARC: mm: do_page_fault refactor #6: error handlers to use same pattern
  ARC: mm: do_page_fault refactor #5: scoot no_context to end
  ARC: mm: do_page_fault refactor #4: consolidate retry related logic
  ARC: mm: do_page_fault refactor #3: tidyup vma access permission code
  ARC: mm: do_page_fault refactor #2: remove short lived variable
  ARC: mm: do_page_fault refactor #1: remove label @good_area

5 files changed, 26 insertions, 58 deletions

diff --git a/arch/arc/kernel/asm-offsets.c b/arch/arc/kernel/asm-offsets.c
index dba116535005..1f621e416521 100644
--- a/arch/arc/kernel/asm-offsets.c
+++ b/arch/arc/kernel/asm-offsets.c
@@ -55,7 +55,14 @@ int main(void)
 	DEFINE(PT_r5, offsetof(struct pt_regs, r5));
 	DEFINE(PT_r6, offsetof(struct pt_regs, r6));
 	DEFINE(PT_r7, offsetof(struct pt_regs, r7));
+	DEFINE(PT_r8, offsetof(struct pt_regs, r8));
+	DEFINE(PT_r10, offsetof(struct pt_regs, r10));
+	DEFINE(PT_r26, offsetof(struct pt_regs, r26));
 	DEFINE(PT_ret, offsetof(struct pt_regs, ret));
+	DEFINE(PT_blink, offsetof(struct pt_regs, blink));
+	DEFINE(PT_lpe, offsetof(struct pt_regs, lp_end));
+	DEFINE(PT_lpc, offsetof(struct pt_regs, lp_count));
+	DEFINE(PT_user_r25, offsetof(struct pt_regs, user_r25));
 
 	DEFINE(SZ_CALLEE_REGS, sizeof(struct callee_regs));
 	DEFINE(SZ_PT_REGS, sizeof(struct pt_regs));
diff --git a/arch/arc/kernel/entry-arcv2.S b/arch/arc/kernel/entry-arcv2.S
index 14254b866fdc..12d5f12d10d2 100644
--- a/arch/arc/kernel/entry-arcv2.S
+++ b/arch/arc/kernel/entry-arcv2.S
@@ -67,7 +67,7 @@ reserved:
 
 ENTRY(handle_interrupt)
 
-	INTERRUPT_PROLOGUE  irq
+	INTERRUPT_PROLOGUE
 
 	# irq control APIs local_irq_save/restore/disable/enable fiddle with
 	# global interrupt enable bits in STATUS32 (.IE for 1 prio, .E[] for 2 prio)
@@ -79,7 +79,7 @@ ENTRY(handle_interrupt)
 	#
 	# Note this disable is only for consistent book-keeping as further interrupts
 	# will be disabled anyways even w/o this. Hardware tracks active interrupts
-	# seperately in AUX_IRQ_ACTIVE.active and will not take new interrupts
+	# seperately in AUX_IRQ_ACT.active and will not take new interrupts
 	# unless this one returns (or higher prio becomes pending in 2-prio scheme)
 
 	IRQ_DISABLE
@@ -200,17 +200,18 @@ restore_regs:
 	ld	r0, [sp, PT_status32]	; U/K mode at time of entry
 	lr	r10, [AUX_IRQ_ACT]
 
-	bmsk	r11, r10, 15	; AUX_IRQ_ACT.ACTIVE
+	bmsk	r11, r10, 15		; extract AUX_IRQ_ACT.active
 	breq	r11, 0, .Lexcept_ret	; No intr active, ret from Exception
 
 ;####### Return from Intr #######
 
+.Lisr_ret:
+
 debug_marker_l1:
 	; bbit1.nt r0, STATUS_DE_BIT, .Lintr_ret_to_delay_slot
 	btst	r0, STATUS_DE_BIT		; Z flag set if bit clear
 	bnz	.Lintr_ret_to_delay_slot	; branch if STATUS_DE_BIT set
 
-.Lisr_ret_fast_path:
 	; Handle special case #1: (Entry via Exception, Return via IRQ)
 	;
 	; Exception in U mode, preempted in kernel, Intr taken (K mode), orig
@@ -223,7 +224,7 @@ debug_marker_l1:
 	bset.nz	r11, r11, AUX_IRQ_ACT_BIT_U	; NZ means U
 	sr	r11, [AUX_IRQ_ACT]
 
-	INTERRUPT_EPILOGUE  irq
+	INTERRUPT_EPILOGUE
 	rtie
 
 ;####### Return from Exception / pure kernel mode #######
@@ -244,8 +245,8 @@ debug_marker_syscall:
 ;
 ; IRQ RTIE won't reliably restore DE bit and/or BTA, needs workaround
 ;
-; Solution is return from Intr w/o any delay slot quirks into a kernel trampoline
-; and from pure kernel mode return to delay slot which handles DS bit/BTA correctly
+; Solution is to drop out of interrupt context into pure kernel mode
+; and return from pure kernel mode which does right things for delay slot
 
 .Lintr_ret_to_delay_slot:
 debug_marker_ds:
@@ -254,48 +255,9 @@ debug_marker_ds:
 	add	r2, r2, 1
 	st	r2, [@intr_to_DE_cnt]
 
-	ld	r2, [sp, PT_ret]
-	ld	r3, [sp, PT_status32]
-
-	; STAT32 for Int return created from scratch
-	; (No delay dlot, disable Further intr in trampoline)
-
-	bic  	r0, r3, STATUS_U_MASK|STATUS_DE_MASK|STATUS_IE_MASK|STATUS_L_MASK
-	st	r0, [sp, PT_status32]
-
-	mov	r1, .Lintr_ret_to_delay_slot_2
-	st	r1, [sp, PT_ret]
-
-	; Orig exception PC/STAT32 safekept @orig_r0 and @event stack slots
-	st	r2, [sp, 0]
-	st	r3, [sp, 4]
-
-	b	.Lisr_ret_fast_path
-
-.Lintr_ret_to_delay_slot_2:
-	; Trampoline to restore orig exception PC/STAT32/BTA/AUX_USER_SP
-	sub	sp, sp, SZ_PT_REGS
-	st	r9, [sp, -4]
-
-	ld	r9, [sp, 0]
-	sr	r9, [eret]
-
-	ld	r9, [sp, 4]
-	sr	r9, [erstatus]
-
-	; restore AUX_USER_SP if returning to U mode
-	bbit0	r9, STATUS_U_BIT, 1f
-	ld	r9, [sp, PT_sp]
-	sr	r9, [AUX_USER_SP]
-
-1:
-	ld	r9, [sp, 8]
-	sr	r9, [erbta]
-
-	ld	r9, [sp, -4]
-	add	sp, sp, SZ_PT_REGS
-
-	; return from pure kernel mode to delay slot
-	rtie
+	; drop out of interrupt context (clear AUX_IRQ_ACT.active)
+	bmskn	r11, r10, 15
+	sr	r11, [AUX_IRQ_ACT]
+	b	.Lexcept_ret
 
 END(ret_from_exception)
diff --git a/arch/arc/kernel/entry-compact.S b/arch/arc/kernel/entry-compact.S
index 7fe59880c16b..5cb0cd7e4eab 100644
--- a/arch/arc/kernel/entry-compact.S
+++ b/arch/arc/kernel/entry-compact.S
@@ -256,7 +256,7 @@ ENTRY(EV_TLBProtV)
 
 	EXCEPTION_PROLOGUE
 
-	mov r2, r9	; ECR set into r9 already
+	mov r2, r10	; ECR set into r10 already
 	lr  r0, [efa]	; Faulting Data address (not part of pt_regs saved above)
 
 	; Exception auto-disables further Intr/exceptions.
diff --git a/arch/arc/kernel/entry.S b/arch/arc/kernel/entry.S
index a2bfacbcfce1..72be01270e24 100644
--- a/arch/arc/kernel/entry.S
+++ b/arch/arc/kernel/entry.S
@@ -232,8 +232,8 @@ ENTRY(EV_Trap)
 	EXCEPTION_PROLOGUE
 
 	;============ TRAP 1   :breakpoints
-	; Check ECR for trap with arg (PROLOGUE ensures r9 has ECR)
-	bmsk.f 0, r9, 7
+	; Check ECR for trap with arg (PROLOGUE ensures r10 has ECR)
+	bmsk.f 0, r10, 7
 	bnz    trap_with_param
 
 	;============ TRAP  (no param): syscall top level
diff --git a/arch/arc/kernel/unwind.c b/arch/arc/kernel/unwind.c
index 182ce67dfe10..c2663fce7f6c 100644
--- a/arch/arc/kernel/unwind.c
+++ b/arch/arc/kernel/unwind.c
@@ -181,11 +181,6 @@ static void *__init unw_hdr_alloc_early(unsigned long sz)
 	return memblock_alloc_from(sz, sizeof(unsigned int), MAX_DMA_ADDRESS);
 }
 
-static void *unw_hdr_alloc(unsigned long sz)
-{
-	return kmalloc(sz, GFP_KERNEL);
-}
-
 static void init_unwind_table(struct unwind_table *table, const char *name,
 			      const void *core_start, unsigned long core_size,
 			      const void *init_start, unsigned long init_size,
@@ -366,6 +361,10 @@ ret_err:
 }
 
 #ifdef CONFIG_MODULES
+static void *unw_hdr_alloc(unsigned long sz)
+{
+	return kmalloc(sz, GFP_KERNEL);
+}
 
 static struct unwind_table *last_table;