Merge tag 'xtensa-for-next-20140815' into for_next

Xtensa improvements for 3.17:
- support highmem on cores with aliasing data cache. Enable highmem on kc705
  by default;
- simplify addition of new core variants (no need to modify Kconfig /
  Makefiles);
- improve robustness of unaligned access handler and its interaction with
  window overflow/underflow exception handlers;
- deprecate atomic and spill registers syscalls;
- clean up Kconfig: remove orphan MATH_EMULATION, sort 'select' statements;
- wire up renameat2 syscall.

Various fixes:
- fix address checks in dma_{alloc,free}_coherent (runtime BUG);
- fix access to THREAD_RA/THREAD_SP/THREAD_DS (debug build breakage);
- fix TLBTEMP_BASE_2 region handling in fast_second_level_miss (runtime
  unrecoverable exception);
- fix a6 and a7 handling in fast_syscall_xtensa (runtime userspace register
  clobbering);
- fix kernel/user jump out of fast_unaligned (potential runtime unrecoverable
  exception);
- replace termios IOCTL code definitions with constants (userspace build
  breakage).

Signed-off-by: Chris Zankel <chris@zankel.net>

6 files changed, 139 insertions, 72 deletions

diff --git a/arch/xtensa/kernel/align.S b/arch/xtensa/kernel/align.S
index d4cef6039a5c..890004af03a9 100644
--- a/arch/xtensa/kernel/align.S
+++ b/arch/xtensa/kernel/align.S
@@ -8,6 +8,7 @@
  * this archive for more details.
  *
  * Copyright (C) 2001 - 2005 Tensilica, Inc.
+ * Copyright (C) 2014 Cadence Design Systems Inc.
  *
  * Rewritten by Chris Zankel <chris@zankel.net>
  *
@@ -174,6 +175,10 @@ ENTRY(fast_unaligned)
 	s32i	a0, a2, PT_AREG2
 	s32i	a3, a2, PT_AREG3
 
+	rsr	a3, excsave1
+	movi	a4, fast_unaligned_fixup
+	s32i	a4, a3, EXC_TABLE_FIXUP
+
 	/* Keep value of SAR in a0 */
 
 	rsr	a0, sar
@@ -225,10 +230,6 @@ ENTRY(fast_unaligned)
 	addx8	a5, a6, a5
 	jx	a5			# jump into table
 
-	/* Invalid instruction, CRITICAL! */
-.Linvalid_instruction_load:
-	j	.Linvalid_instruction
-
 	/* Load: Load memory address. */
 
 .Lload: movi	a3, ~3
@@ -272,18 +273,6 @@ ENTRY(fast_unaligned)
 	/* Set target register. */
 
 1:
-
-#if XCHAL_HAVE_LOOPS
-	rsr	a5, lend		# check if we reached LEND
-	bne	a7, a5, 1f
-	rsr	a5, lcount		# and LCOUNT != 0
-	beqz	a5, 1f
-	addi	a5, a5, -1		# decrement LCOUNT and set
-	rsr	a7, lbeg		# set PC to LBEGIN
-	wsr	a5, lcount
-#endif
-
-1:	wsr	a7, epc1		# skip load instruction
 	extui	a4, a4, INSN_T, 4	# extract target register
 	movi	a5, .Lload_table
 	addx8	a4, a4, a5
@@ -326,6 +315,35 @@ ENTRY(fast_unaligned)
 	mov	a3, a14		;	_j 1f;	.align 8
 	mov	a3, a15		;	_j 1f;	.align 8
 
+	/* We cannot handle this exception. */
+
+	.extern _kernel_exception
+.Linvalid_instruction_load:
+.Linvalid_instruction_store:
+
+	movi	a4, 0
+	rsr	a3, excsave1
+	s32i	a4, a3, EXC_TABLE_FIXUP
+
+	/* Restore a4...a8 and SAR, set SP, and jump to default exception. */
+
+	l32i	a8, a2, PT_AREG8
+	l32i	a7, a2, PT_AREG7
+	l32i	a6, a2, PT_AREG6
+	l32i	a5, a2, PT_AREG5
+	l32i	a4, a2, PT_AREG4
+	wsr	a0, sar
+	mov	a1, a2
+
+	rsr	a0, ps
+	bbsi.l  a0, PS_UM_BIT, 2f     # jump if user mode
+
+	movi	a0, _kernel_exception
+	jx	a0
+
+2:	movi	a0, _user_exception
+	jx	a0
+
 1: 	# a7: instruction pointer, a4: instruction, a3: value
 
 	movi	a6, 0			# mask: ffffffff:00000000
@@ -353,17 +371,6 @@ ENTRY(fast_unaligned)
 	/* Get memory address */
 
 1:
-#if XCHAL_HAVE_LOOPS
-	rsr	a4, lend		# check if we reached LEND
-	bne	a7, a4, 1f
-	rsr	a4, lcount		# and LCOUNT != 0
-	beqz	a4, 1f
-	addi	a4, a4, -1		# decrement LCOUNT and set
-	rsr	a7, lbeg		# set PC to LBEGIN
-	wsr	a4, lcount
-#endif
-
-1:	wsr	a7, epc1		# skip store instruction
 	movi	a4, ~3
 	and	a4, a4, a8		# align memory address
 
@@ -375,25 +382,25 @@ ENTRY(fast_unaligned)
 #endif
 
 	__ssa8r a8
-	__src_b	a7, a5, a6		# lo-mask  F..F0..0 (BE) 0..0F..F (LE)
+	__src_b	a8, a5, a6		# lo-mask  F..F0..0 (BE) 0..0F..F (LE)
 	__src_b	a6, a6, a5		# hi-mask  0..0F..F (BE) F..F0..0 (LE)
 #ifdef UNALIGNED_USER_EXCEPTION
 	l32e	a5, a4, -8
 #else
 	l32i	a5, a4, 0		# load lower address word
 #endif
-	and	a5, a5, a7		# mask
-	__sh	a7, a3 			# shift value
-	or	a5, a5, a7		# or with original value
+	and	a5, a5, a8		# mask
+	__sh	a8, a3 			# shift value
+	or	a5, a5, a8		# or with original value
 #ifdef UNALIGNED_USER_EXCEPTION
 	s32e	a5, a4, -8
-	l32e	a7, a4, -4
+	l32e	a8, a4, -4
 #else
 	s32i	a5, a4, 0		# store
-	l32i	a7, a4, 4		# same for upper address word
+	l32i	a8, a4, 4		# same for upper address word
 #endif
 	__sl	a5, a3
-	and	a6, a7, a6
+	and	a6, a8, a6
 	or	a6, a6, a5
 #ifdef UNALIGNED_USER_EXCEPTION
 	s32e	a6, a4, -4
@@ -401,9 +408,27 @@ ENTRY(fast_unaligned)
 	s32i	a6, a4, 4
 #endif
 
-	/* Done. restore stack and return */
-
 .Lexit:
+#if XCHAL_HAVE_LOOPS
+	rsr	a4, lend		# check if we reached LEND
+	bne	a7, a4, 1f
+	rsr	a4, lcount		# and LCOUNT != 0
+	beqz	a4, 1f
+	addi	a4, a4, -1		# decrement LCOUNT and set
+	rsr	a7, lbeg		# set PC to LBEGIN
+	wsr	a4, lcount
+#endif
+
+1:	wsr	a7, epc1		# skip emulated instruction
+
+	/* Update icount if we're single-stepping in userspace. */
+	rsr	a4, icountlevel
+	beqz	a4, 1f
+	bgeui	a4, LOCKLEVEL + 1, 1f
+	rsr	a4, icount
+	addi	a4, a4, 1
+	wsr	a4, icount
+1:
 	movi	a4, 0
 	rsr	a3, excsave1
 	s32i	a4, a3, EXC_TABLE_FIXUP
@@ -424,31 +449,40 @@ ENTRY(fast_unaligned)
 	l32i	a2, a2, PT_AREG2
 	rfe
 
-	/* We cannot handle this exception. */
+ENDPROC(fast_unaligned)
 
-	.extern _kernel_exception
-.Linvalid_instruction_store:
-.Linvalid_instruction:
+ENTRY(fast_unaligned_fixup)
 
-	/* Restore a4...a8 and SAR, set SP, and jump to default exception. */
+	l32i	a2, a3, EXC_TABLE_DOUBLE_SAVE
+	wsr	a3, excsave1
 
 	l32i	a8, a2, PT_AREG8
 	l32i	a7, a2, PT_AREG7
 	l32i	a6, a2, PT_AREG6
 	l32i	a5, a2, PT_AREG5
 	l32i	a4, a2, PT_AREG4
+	l32i	a0, a2, PT_AREG2
+	xsr	a0, depc			# restore depc and a0
 	wsr	a0, sar
-	mov	a1, a2
+
+	rsr	a0, exccause
+	s32i	a0, a2, PT_DEPC			# mark as a regular exception
 
 	rsr	a0, ps
-	bbsi.l  a2, PS_UM_BIT, 1f     # jump if user mode
+	bbsi.l  a0, PS_UM_BIT, 1f		# jump if user mode
 
-	movi	a0, _kernel_exception
+	rsr	a0, exccause
+	addx4	a0, a0, a3              	# find entry in table
+	l32i	a0, a0, EXC_TABLE_FAST_KERNEL   # load handler
+	l32i	a3, a2, PT_AREG3
 	jx	a0
-
-1:	movi	a0, _user_exception
+1:
+	rsr	a0, exccause
+	addx4	a0, a0, a3              	# find entry in table
+	l32i	a0, a0, EXC_TABLE_FAST_USER     # load handler
+	l32i	a3, a2, PT_AREG3
 	jx	a0
 
-ENDPROC(fast_unaligned)
+ENDPROC(fast_unaligned_fixup)
 
 #endif /* XCHAL_UNALIGNED_LOAD_EXCEPTION || XCHAL_UNALIGNED_STORE_EXCEPTION */
diff --git a/arch/xtensa/kernel/entry.S b/arch/xtensa/kernel/entry.S
index ef7f4990722b..82bbfa5a05b3 100644
--- a/arch/xtensa/kernel/entry.S
+++ b/arch/xtensa/kernel/entry.S
@@ -986,6 +986,8 @@ ENDPROC(fast_syscall_unrecoverable)
  *		j done
  */
 
+#ifdef CONFIG_FAST_SYSCALL_XTENSA
+
 #define TRY								\
 	.section __ex_table, "a";					\
 	.word	66f, 67f;						\
@@ -1001,9 +1003,8 @@ ENTRY(fast_syscall_xtensa)
 	movi	a7, 4			# sizeof(unsigned int)
 	access_ok a3, a7, a0, a2, .Leac	# a0: scratch reg, a2: sp
 
-	addi	a6, a6, -1		# assuming SYS_XTENSA_ATOMIC_SET = 1
-	_bgeui	a6, SYS_XTENSA_COUNT - 1, .Lill
-	_bnei	a6, SYS_XTENSA_ATOMIC_CMP_SWP - 1, .Lnswp
+	_bgeui	a6, SYS_XTENSA_COUNT, .Lill
+	_bnei	a6, SYS_XTENSA_ATOMIC_CMP_SWP, .Lnswp
 
 	/* Fall through for ATOMIC_CMP_SWP. */
 
@@ -1015,27 +1016,26 @@ TRY	s32i	a5, a3, 0		# different, modify value
 	l32i	a7, a2, PT_AREG7	# restore a7
 	l32i	a0, a2, PT_AREG0	# restore a0
 	movi	a2, 1			# and return 1
-	addi	a6, a6, 1		# restore a6 (really necessary?)
 	rfe
 
 1:	l32i	a7, a2, PT_AREG7	# restore a7
 	l32i	a0, a2, PT_AREG0	# restore a0
 	movi	a2, 0			# return 0 (note that we cannot set
-	addi	a6, a6, 1		# restore a6 (really necessary?)
 	rfe
 
 .Lnswp:	/* Atomic set, add, and exg_add. */
 
 TRY	l32i	a7, a3, 0		# orig
+	addi	a6, a6, -SYS_XTENSA_ATOMIC_SET
 	add	a0, a4, a7		# + arg
 	moveqz	a0, a4, a6		# set
+	addi	a6, a6, SYS_XTENSA_ATOMIC_SET
 TRY	s32i	a0, a3, 0		# write new value
 
 	mov	a0, a2
 	mov	a2, a7
 	l32i	a7, a0, PT_AREG7	# restore a7
 	l32i	a0, a0, PT_AREG0	# restore a0
-	addi	a6, a6, 1		# restore a6 (really necessary?)
 	rfe
 
 CATCH
@@ -1044,13 +1044,25 @@ CATCH
 	movi	a2, -EFAULT
 	rfe
 
-.Lill:	l32i	a7, a2, PT_AREG0	# restore a7
+.Lill:	l32i	a7, a2, PT_AREG7	# restore a7
 	l32i	a0, a2, PT_AREG0	# restore a0
 	movi	a2, -EINVAL
 	rfe
 
 ENDPROC(fast_syscall_xtensa)
 
+#else /* CONFIG_FAST_SYSCALL_XTENSA */
+
+ENTRY(fast_syscall_xtensa)
+
+	l32i    a0, a2, PT_AREG0        # restore a0
+	movi	a2, -ENOSYS
+	rfe
+
+ENDPROC(fast_syscall_xtensa)
+
+#endif /* CONFIG_FAST_SYSCALL_XTENSA */
+
 
 /* fast_syscall_spill_registers.
  *
@@ -1066,6 +1078,8 @@ ENDPROC(fast_syscall_xtensa)
  * Note: We assume the stack pointer is EXC_TABLE_KSTK in the fixup handler.
  */
 
+#ifdef CONFIG_FAST_SYSCALL_SPILL_REGISTERS
+
 ENTRY(fast_syscall_spill_registers)
 
 	/* Register a FIXUP handler (pass current wb as a parameter) */
@@ -1400,6 +1414,18 @@ ENTRY(fast_syscall_spill_registers_fixup_return)
 
 ENDPROC(fast_syscall_spill_registers_fixup_return)
 
+#else /* CONFIG_FAST_SYSCALL_SPILL_REGISTERS */
+
+ENTRY(fast_syscall_spill_registers)
+
+	l32i    a0, a2, PT_AREG0        # restore a0
+	movi	a2, -ENOSYS
+	rfe
+
+ENDPROC(fast_syscall_spill_registers)
+
+#endif /* CONFIG_FAST_SYSCALL_SPILL_REGISTERS */
+
 #ifdef CONFIG_MMU
 /*
  * We should never get here. Bail out!
@@ -1565,7 +1591,7 @@ ENTRY(fast_second_level_miss)
 	rsr	a0, excvaddr
 	bltu	a0, a3, 2f
 
-	addi	a1, a0, -(2 << (DCACHE_ALIAS_ORDER + PAGE_SHIFT))
+	addi	a1, a0, -TLBTEMP_SIZE
 	bgeu	a1, a3, 2f
 
 	/* Check if we have to restore an ITLB mapping. */
@@ -1820,7 +1846,6 @@ ENTRY(_switch_to)
 
 	entry	a1, 16
 
-	mov	a10, a2			# preserve 'prev' (a2)
 	mov	a11, a3			# and 'next' (a3)
 
 	l32i	a4, a2, TASK_THREAD_INFO
@@ -1828,8 +1853,14 @@ ENTRY(_switch_to)
 
 	save_xtregs_user a4 a6 a8 a9 a12 a13 THREAD_XTREGS_USER
 
-	s32i	a0, a10, THREAD_RA	# save return address
-	s32i	a1, a10, THREAD_SP	# save stack pointer
+#if THREAD_RA > 1020 || THREAD_SP > 1020
+	addi	a10, a2, TASK_THREAD
+	s32i	a0, a10, THREAD_RA - TASK_THREAD	# save return address
+	s32i	a1, a10, THREAD_SP - TASK_THREAD	# save stack pointer
+#else
+	s32i	a0, a2, THREAD_RA	# save return address
+	s32i	a1, a2, THREAD_SP	# save stack pointer
+#endif
 
 	/* Disable ints while we manipulate the stack pointer. */
 
@@ -1870,7 +1901,6 @@ ENTRY(_switch_to)
 	load_xtregs_user a5 a6 a8 a9 a12 a13 THREAD_XTREGS_USER
 
 	wsr	a14, ps
-	mov	a2, a10			# return 'prev'
 	rsync
 
 	retw
diff --git a/arch/xtensa/kernel/pci-dma.c b/arch/xtensa/kernel/pci-dma.c
index 2d9cc6dbfd78..e8b76b8e4b29 100644
--- a/arch/xtensa/kernel/pci-dma.c
+++ b/arch/xtensa/kernel/pci-dma.c
@@ -49,9 +49,8 @@ dma_alloc_coherent(struct device *dev,size_t size,dma_addr_t *handle,gfp_t flag)
 
 	/* We currently don't support coherent memory outside KSEG */
 
-	if (ret < XCHAL_KSEG_CACHED_VADDR
-	    || ret >= XCHAL_KSEG_CACHED_VADDR + XCHAL_KSEG_SIZE)
-		BUG();
+	BUG_ON(ret < XCHAL_KSEG_CACHED_VADDR ||
+	       ret > XCHAL_KSEG_CACHED_VADDR + XCHAL_KSEG_SIZE - 1);
 
 
 	if (ret != 0) {
@@ -68,10 +67,11 @@ EXPORT_SYMBOL(dma_alloc_coherent);
 void dma_free_coherent(struct device *hwdev, size_t size,
 			 void *vaddr, dma_addr_t dma_handle)
 {
-	long addr=(long)vaddr+XCHAL_KSEG_CACHED_VADDR-XCHAL_KSEG_BYPASS_VADDR;
+	unsigned long addr = (unsigned long)vaddr +
+		XCHAL_KSEG_CACHED_VADDR - XCHAL_KSEG_BYPASS_VADDR;
 
-	if (addr < 0 || addr >= XCHAL_KSEG_SIZE)
-		BUG();
+	BUG_ON(addr < XCHAL_KSEG_CACHED_VADDR ||
+	       addr > XCHAL_KSEG_CACHED_VADDR + XCHAL_KSEG_SIZE - 1);
 
 	free_pages(addr, get_order(size));
 }
diff --git a/arch/xtensa/kernel/traps.c b/arch/xtensa/kernel/traps.c
index eebbfd8c26fc..9d2f45f010ef 100644
--- a/arch/xtensa/kernel/traps.c
+++ b/arch/xtensa/kernel/traps.c
@@ -101,9 +101,8 @@ static dispatch_init_table_t __initdata dispatch_init_table[] = {
 #if XCHAL_UNALIGNED_LOAD_EXCEPTION || XCHAL_UNALIGNED_STORE_EXCEPTION
 #ifdef CONFIG_XTENSA_UNALIGNED_USER
 { EXCCAUSE_UNALIGNED,		USER,	   fast_unaligned },
-#else
-{ EXCCAUSE_UNALIGNED,		0,	   do_unaligned_user },
 #endif
+{ EXCCAUSE_UNALIGNED,		0,	   do_unaligned_user },
 { EXCCAUSE_UNALIGNED,		KRNL,	   fast_unaligned },
 #endif
 #ifdef CONFIG_MMU
@@ -264,7 +263,6 @@ do_illegal_instruction(struct pt_regs *regs)
  */
 
 #if XCHAL_UNALIGNED_LOAD_EXCEPTION || XCHAL_UNALIGNED_STORE_EXCEPTION
-#ifndef CONFIG_XTENSA_UNALIGNED_USER
 void
 do_unaligned_user (struct pt_regs *regs)
 {
@@ -286,7 +284,6 @@ do_unaligned_user (struct pt_regs *regs)
 
 }
 #endif
-#endif
 
 void
 do_debug(struct pt_regs *regs)
diff --git a/arch/xtensa/kernel/vectors.S b/arch/xtensa/kernel/vectors.S
index 8453e6e39895..1b397a902292 100644
--- a/arch/xtensa/kernel/vectors.S
+++ b/arch/xtensa/kernel/vectors.S
@@ -454,8 +454,14 @@ _DoubleExceptionVector_WindowOverflow:
 	s32i	a0, a2, PT_DEPC
 
 _DoubleExceptionVector_handle_exception:
+	addi	a0, a0, -EXCCAUSE_UNALIGNED
+	beqz	a0, 2f
 	addx4	a0, a0, a3
-	l32i	a0, a0, EXC_TABLE_FAST_USER
+	l32i	a0, a0, EXC_TABLE_FAST_USER + 4 * EXCCAUSE_UNALIGNED
+	xsr	a3, excsave1
+	jx	a0
+2:
+	movi	a0, user_exception
 	xsr	a3, excsave1
 	jx	a0
 
diff --git a/arch/xtensa/kernel/vmlinux.lds.S b/arch/xtensa/kernel/vmlinux.lds.S
index d16db6df86f8..fc1bc2ba8d5d 100644
--- a/arch/xtensa/kernel/vmlinux.lds.S
+++ b/arch/xtensa/kernel/vmlinux.lds.S
@@ -269,13 +269,13 @@ SECTIONS
 		  .UserExceptionVector.literal)
   SECTION_VECTOR (_DoubleExceptionVector_literal,
 		  .DoubleExceptionVector.literal,
-		  DOUBLEEXC_VECTOR_VADDR - 40,
+		  DOUBLEEXC_VECTOR_VADDR - 48,
 		  SIZEOF(.UserExceptionVector.text),
 		  .UserExceptionVector.text)
   SECTION_VECTOR (_DoubleExceptionVector_text,
 		  .DoubleExceptionVector.text,
 		  DOUBLEEXC_VECTOR_VADDR,
-		  40,
+		  48,
 		  .DoubleExceptionVector.literal)
 
   . = (LOADADDR( .DoubleExceptionVector.text ) + SIZEOF( .DoubleExceptionVector.text ) + 3) & ~ 3;