[PATCH v2 00/11] xtensa queue 2013/08/30

[PATCH v2 00/11] xtensa queue 2013/08/30

[Max Filippov]

Hi Chris,

this is my current patch queue for xtensa, it is based on your for_next
branch.
There are fixes for the current issues:
- missing #include <asm/ftrace.h> that fixes build with enabled support for
  modules and tracing;
- fix for build warning on 64bit hosts;
- echo doesn't need -e, which breaks big endian variants build when the shell
  is dash;
- TIF_* flags are now checked atomically, and hardirqs tracing call is moved
  after possible rescheduling point;
- provide ccount_freq definition regardless of CONFIG_XTENSA_CALIBRATE_CCOUNT
  which fixes build with CONFIG_XTENSA_CALIBRATE_CCOUNT disabled;
- replace CCOUNT_PER_JIFFY with ccount_freq and simplify resulting
  expressions; remove CCOUNT_PER_JIFFY definition.
There's a patch that enables kernel preemption.
The rest are prerequisites and fixes for SMP:
- spinlock functions are renamed according to current kernel naming scheme,
  asm/spinlock_types.h is provided;
- exception handlers now get a3 and excsave reversed, exc_table reloads in
  entry.S are eliminated. This patch is ported from 2.6.29-smp;
- new fast_alloca handler is ported from 2.6.29-smp;
- __delay is fixed for small delays, which in turn fixes SMP kernel hangs
  with CONFIG_DEBUG_SPINLOCK enabled.

You can pull these changes from my git tree,
the following changes since commit 3b2f64d00c46e1e4e9bd0bb9bb12619adac27a4b:

  Linux 3.11-rc2 (2013-07-21 12:05:29 -0700)

are available in the git repository at:
  git://github.com/jcmvbkbc/linux-xtensa.git xtensa-fixes-for-upstream

Changes v1->v2:
- make __delay fix more explicit for constant delays less than 2;
- remove unneeded call to trace_hardirqs_off from TIF_* checking patch;
- add timer-related patches from Baruch Siach.
 
Baruch Siach (2):
  xtensa: fix !CONFIG_XTENSA_CALIBRATE_CCOUNT build failure
  xtensa: remove CCOUNT_PER_JIFFY

Chen Gang (1):
  xtensa: kernel: add "asm/ftrace.h" for pass compiling

Max Filippov (8):
  xtensa: fix arch spinlock function names
  xtensa: fix __delay for small loop count
  xtensa: fix build warning
  xtensa: check thread flags atomically on return from user exception
  xtensa: enable kernel preemption
  xtensa: keep a3 and excsave1 on entry to exception handlers
  xtensa: new fast_alloca handler
  xtensa: don't use echo -e needlessly

 arch/xtensa/Makefile                     |    4 +-
 arch/xtensa/boot/Makefile                |    2 +-
 arch/xtensa/include/asm/delay.h          |    9 +-
 arch/xtensa/include/asm/regs.h           |    1 +
 arch/xtensa/include/asm/spinlock.h       |   31 ++-
 arch/xtensa/include/asm/spinlock_types.h |   20 ++
 arch/xtensa/include/asm/timex.h          |    6 -
 arch/xtensa/kernel/align.S               |    5 +-
 arch/xtensa/kernel/coprocessor.S         |    9 +-
 arch/xtensa/kernel/entry.S               |  387 ++++++++++--------------------
 arch/xtensa/kernel/setup.c               |    4 +-
 arch/xtensa/kernel/time.c                |    8 +-
 arch/xtensa/kernel/vectors.S             |  250 ++++++++++++++-----
 arch/xtensa/kernel/xtensa_ksyms.c        |    3 +
 arch/xtensa/mm/misc.S                    |    4 +-
 15 files changed, 371 insertions(+), 372 deletions(-)
 create mode 100644 arch/xtensa/include/asm/spinlock_types.h

-- 
1.7.7.6

[PATCH v2 01/11] xtensa: kernel: add "asm/ftrace.h" for pass compiling

[Max Filippov]

From: Chen Gang <gang.chen@asianux.com>

Need add "asm/ftrace.h" for pass compiling.

Cross-compiler is compiled from binutils-2.23.2 and gcc-4.9.0 source.

The related error (with allmodconfig for fsf processor):

  arch/xtensa/kernel/xtensa_ksyms.c:129:15: error: '_mcount' undeclared here (not in a function)

Signed-off-by: Chen Gang <gang.chen@asianux.com>
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
---
 arch/xtensa/kernel/xtensa_ksyms.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)

diff --git a/arch/xtensa/kernel/xtensa_ksyms.c b/arch/xtensa/kernel/xtensa_ksyms.c
index d8507f8..316f008 100644
--- a/arch/xtensa/kernel/xtensa_ksyms.c
+++ b/arch/xtensa/kernel/xtensa_ksyms.c
@@ -32,6 +32,9 @@
 #include <net/checksum.h>
 #endif /* CONFIG_NET */
 
+#ifdef CONFIG_FUNCTION_TRACER
+#include <asm/ftrace.h>
+#endif /* CONFIG_FUNCTION_TRACER */
 
 /*
  * String functions
-- 
1.7.7.6

[PATCH v2 02/11] xtensa: fix arch spinlock function names

[Max Filippov]

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
---
 arch/xtensa/include/asm/spinlock.h       |   31 ++++++++++++++++-------------
 arch/xtensa/include/asm/spinlock_types.h |   20 +++++++++++++++++++
 2 files changed, 37 insertions(+), 14 deletions(-)
 create mode 100644 arch/xtensa/include/asm/spinlock_types.h

diff --git a/arch/xtensa/include/asm/spinlock.h b/arch/xtensa/include/asm/spinlock.h
index 0397590..1d95fa5 100644
--- a/arch/xtensa/include/asm/spinlock.h
+++ b/arch/xtensa/include/asm/spinlock.h
@@ -28,13 +28,13 @@
  *    1         somebody owns the spinlock
  */
 
-#define __raw_spin_is_locked(x) ((x)->slock != 0)
-#define __raw_spin_unlock_wait(lock) \
-	do { while (__raw_spin_is_locked(lock)) cpu_relax(); } while (0)
+#define arch_spin_is_locked(x) ((x)->slock != 0)
+#define arch_spin_unlock_wait(lock) \
+	do { while (arch_spin_is_locked(lock)) cpu_relax(); } while (0)
 
-#define __raw_spin_lock_flags(lock, flags) __raw_spin_lock(lock)
+#define arch_spin_lock_flags(lock, flags) arch_spin_lock(lock)
 
-static inline void __raw_spin_lock(raw_spinlock_t *lock)
+static inline void arch_spin_lock(arch_spinlock_t *lock)
 {
 	unsigned long tmp;
 
@@ -51,7 +51,7 @@ static inline void __raw_spin_lock(raw_spinlock_t *lock)
 
 /* Returns 1 if the lock is obtained, 0 otherwise. */
 
-static inline int __raw_spin_trylock(raw_spinlock_t *lock)
+static inline int arch_spin_trylock(arch_spinlock_t *lock)
 {
 	unsigned long tmp;
 
@@ -67,7 +67,7 @@ static inline int __raw_spin_trylock(raw_spinlock_t *lock)
 	return tmp == 0 ? 1 : 0;
 }
 
-static inline void __raw_spin_unlock(raw_spinlock_t *lock)
+static inline void arch_spin_unlock(arch_spinlock_t *lock)
 {
 	unsigned long tmp;
 
@@ -96,9 +96,9 @@ static inline void __raw_spin_unlock(raw_spinlock_t *lock)
  *  0x80000000  one writer owns the rwlock, no other writers, no readers
  */
 
-#define __raw_write_can_lock(x)  ((x)->lock == 0)
+#define arch_write_can_lock(x)  ((x)->lock == 0)
 
-static inline void __raw_write_lock(raw_rwlock_t *rw)
+static inline void arch_write_lock(arch_rwlock_t *rw)
 {
 	unsigned long tmp;
 
@@ -116,7 +116,7 @@ static inline void __raw_write_lock(raw_rwlock_t *rw)
 
 /* Returns 1 if the lock is obtained, 0 otherwise. */
 
-static inline int __raw_write_trylock(raw_rwlock_t *rw)
+static inline int arch_write_trylock(arch_rwlock_t *rw)
 {
 	unsigned long tmp;
 
@@ -133,7 +133,7 @@ static inline int __raw_write_trylock(raw_rwlock_t *rw)
 	return tmp == 0 ? 1 : 0;
 }
 
-static inline void __raw_write_unlock(raw_rwlock_t *rw)
+static inline void arch_write_unlock(arch_rwlock_t *rw)
 {
 	unsigned long tmp;
 
@@ -145,7 +145,7 @@ static inline void __raw_write_unlock(raw_rwlock_t *rw)
 			: "memory");
 }
 
-static inline void __raw_read_lock(raw_rwlock_t *rw)
+static inline void arch_read_lock(arch_rwlock_t *rw)
 {
 	unsigned long tmp;
 	unsigned long result;
@@ -164,7 +164,7 @@ static inline void __raw_read_lock(raw_rwlock_t *rw)
 
 /* Returns 1 if the lock is obtained, 0 otherwise. */
 
-static inline int __raw_read_trylock(raw_rwlock_t *rw)
+static inline int arch_read_trylock(arch_rwlock_t *rw)
 {
 	unsigned long result;
 	unsigned long tmp;
@@ -184,7 +184,7 @@ static inline int __raw_read_trylock(raw_rwlock_t *rw)
 	return result == 0;
 }
 
-static inline void __raw_read_unlock(raw_rwlock_t *rw)
+static inline void arch_read_unlock(arch_rwlock_t *rw)
 {
 	unsigned long tmp1, tmp2;
 
@@ -199,4 +199,7 @@ static inline void __raw_read_unlock(raw_rwlock_t *rw)
 			: "memory");
 }
 
+#define arch_read_lock_flags(lock, flags)	arch_read_lock(lock)
+#define arch_write_lock_flags(lock, flags)	arch_write_lock(lock)
+
 #endif	/* _XTENSA_SPINLOCK_H */
diff --git a/arch/xtensa/include/asm/spinlock_types.h b/arch/xtensa/include/asm/spinlock_types.h
new file mode 100644
index 0000000..7ec5ce1
--- /dev/null
+++ b/arch/xtensa/include/asm/spinlock_types.h
@@ -0,0 +1,20 @@
+#ifndef __ASM_SPINLOCK_TYPES_H
+#define __ASM_SPINLOCK_TYPES_H
+
+#ifndef __LINUX_SPINLOCK_TYPES_H
+# error "please don't include this file directly"
+#endif
+
+typedef struct {
+	volatile unsigned int slock;
+} arch_spinlock_t;
+
+#define __ARCH_SPIN_LOCK_UNLOCKED	{ 0 }
+
+typedef struct {
+	volatile unsigned int lock;
+} arch_rwlock_t;
+
+#define __ARCH_RW_LOCK_UNLOCKED		{ 0 }
+
+#endif
-- 
1.7.7.6

[PATCH v2 03/11] xtensa: fix __delay for small loop count

[Max Filippov]

Avoid __delay counter underflow for loop counts < 2.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
---
Changes v1->v2:
- make __delay fix more explicit for constant delays less than 2;

 arch/xtensa/include/asm/delay.h |    9 ++++++---
 1 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/arch/xtensa/include/asm/delay.h b/arch/xtensa/include/asm/delay.h
index 3899610..742b89f 100644
--- a/arch/xtensa/include/asm/delay.h
+++ b/arch/xtensa/include/asm/delay.h
@@ -19,9 +19,12 @@ extern unsigned long loops_per_jiffy;
 
 static inline void __delay(unsigned long loops)
 {
-	/* 2 cycles per loop. */
-	__asm__ __volatile__ ("1: addi %0, %0, -2; bgeui %0, 2, 1b"
-			      : "=r" (loops) : "0" (loops));
+	if (__builtin_constant_p(loops) && loops < 2)
+		__asm__ __volatile__ ("nop");
+	else if (loops >= 2)
+		/* 2 cycles per loop. */
+		__asm__ __volatile__ ("1: addi %0, %0, -2; bgeui %0, 2, 1b"
+				: "+r" (loops));
 }
 
 /* For SMP/NUMA systems, change boot_cpu_data to something like
-- 
1.7.7.6

[PATCH v2 04/11] xtensa: fix build warning

[Max Filippov]

This fixes the following build warnings:

arch/xtensa/mm/misc.S: Assembler messages:
arch/xtensa/mm/misc.S:143: Warning: value 0xffffffff30000106 truncated to 0x30000106
arch/xtensa/mm/misc.S:197: Warning: value 0xffffffff30000106 truncated to 0x30000106

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
---
 arch/xtensa/mm/misc.S |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/xtensa/mm/misc.S b/arch/xtensa/mm/misc.S
index d97ed1b..1f68558 100644
--- a/arch/xtensa/mm/misc.S
+++ b/arch/xtensa/mm/misc.S
@@ -140,7 +140,7 @@ ENTRY(clear_user_page)
 
 	/* Setup a temporary DTLB with the color of the VPN */
 
-	movi	a4, -PAGE_OFFSET + (PAGE_KERNEL | _PAGE_HW_WRITE)
+	movi	a4, ((PAGE_KERNEL | _PAGE_HW_WRITE) - PAGE_OFFSET) & 0xffffffff
 	movi	a5, TLBTEMP_BASE_1			# virt
 	add	a6, a2, a4				# ppn
 	add	a2, a5, a3				# add 'color'
@@ -194,7 +194,7 @@ ENTRY(copy_user_page)
 	or	a9, a9, a8
 	slli	a4, a4, PAGE_SHIFT
 	s32i	a9, a5, PAGE_FLAGS
-	movi	a5, -PAGE_OFFSET + (PAGE_KERNEL | _PAGE_HW_WRITE)
+	movi	a5, ((PAGE_KERNEL | _PAGE_HW_WRITE) - PAGE_OFFSET) & 0xffffffff
 
 	beqz	a6, 1f
 
-- 
1.7.7.6

[PATCH v2 05/11] xtensa: check thread flags atomically on return from user exception

[Max Filippov]

Check pending signals and rescheduling thread flags with interrupts
disabled, and don't enable them if no flags are set. Call
trace_hardirqs_on after thread flags handling, so that rescheduling is
done and hardirqs tracking flag is updated in the correct task context.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
---
Changes v1->v2:
- remove unneeded call to trace_hardirqs_off from the loop after
  rsil a2, LOCKLEVEL

 arch/xtensa/kernel/entry.S |   39 +++++++++++++++++++++------------------
 1 files changed, 21 insertions(+), 18 deletions(-)

diff --git a/arch/xtensa/kernel/entry.S b/arch/xtensa/kernel/entry.S
index 9298742..03709ef 100644
--- a/arch/xtensa/kernel/entry.S
+++ b/arch/xtensa/kernel/entry.S
@@ -423,29 +423,14 @@ common_exception:
 	.global common_exception_return
 common_exception_return:
 
-#ifdef CONFIG_TRACE_IRQFLAGS
-	l32i	a4, a1, PT_DEPC
-	/* Double exception means we came here with an exception
-	 * while PS.EXCM was set, i.e. interrupts disabled.
-	 */
-	bgeui	a4, VALID_DOUBLE_EXCEPTION_ADDRESS, 1f
-	l32i	a4, a1, PT_EXCCAUSE
-	bnei	a4, EXCCAUSE_LEVEL1_INTERRUPT, 1f
-	/* We came here with an interrupt means interrupts were enabled
-	 * and we'll reenable them on return.
-	 */
-	movi	a4, trace_hardirqs_on
-	callx4	a4
 1:
-#endif
+	rsil	a2, LOCKLEVEL
 
 	/* Jump if we are returning from kernel exceptions. */
 
-1:	l32i	a3, a1, PT_PS
+	l32i	a3, a1, PT_PS
 	_bbci.l	a3, PS_UM_BIT, 4f
 
-	rsil	a2, 0
-
 	/* Specific to a user exception exit:
 	 * We need to check some flags for signal handling and rescheduling,
 	 * and have to restore WB and WS, extra states, and all registers
@@ -465,6 +450,7 @@ common_exception_return:
 
 	/* Call do_signal() */
 
+	rsil	a2, 0
 	movi	a4, do_notify_resume	# int do_notify_resume(struct pt_regs*)
 	mov	a6, a1
 	callx4	a4
@@ -472,6 +458,7 @@ common_exception_return:
 
 3:	/* Reschedule */
 
+	rsil	a2, 0
 	movi	a4, schedule	# void schedule (void)
 	callx4	a4
 	j	1b
@@ -483,7 +470,23 @@ common_exception_return:
 	movi	a4, check_tlb_sanity
 	callx4	a4
 #endif
-4:	/* Restore optional registers. */
+4:
+#ifdef CONFIG_TRACE_IRQFLAGS
+	l32i	a4, a1, PT_DEPC
+	/* Double exception means we came here with an exception
+	 * while PS.EXCM was set, i.e. interrupts disabled.
+	 */
+	bgeui	a4, VALID_DOUBLE_EXCEPTION_ADDRESS, 1f
+	l32i	a4, a1, PT_EXCCAUSE
+	bnei	a4, EXCCAUSE_LEVEL1_INTERRUPT, 1f
+	/* We came here with an interrupt means interrupts were enabled
+	 * and we'll reenable them on return.
+	 */
+	movi	a4, trace_hardirqs_on
+	callx4	a4
+1:
+#endif
+	/* Restore optional registers. */
 
 	load_xtregs_opt a1 a2 a4 a5 a6 a7 PT_XTREGS_OPT
 
-- 
1.7.7.6

[PATCH v2 06/11] xtensa: enable kernel preemption

[Max Filippov]

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
---
 arch/xtensa/kernel/entry.S |   45 ++++++++++++++++---------------------------
 1 files changed, 17 insertions(+), 28 deletions(-)

diff --git a/arch/xtensa/kernel/entry.S b/arch/xtensa/kernel/entry.S
index 03709ef..3f3de28 100644
--- a/arch/xtensa/kernel/entry.S
+++ b/arch/xtensa/kernel/entry.S
@@ -31,7 +31,6 @@
 /* Unimplemented features. */
 
 #undef KERNEL_STACK_OVERFLOW_CHECK
-#undef PREEMPTIBLE_KERNEL
 #undef ALLOCA_EXCEPTION_IN_IRAM
 
 /* Not well tested.
@@ -429,7 +428,9 @@ common_exception_return:
 	/* Jump if we are returning from kernel exceptions. */
 
 	l32i	a3, a1, PT_PS
-	_bbci.l	a3, PS_UM_BIT, 4f
+	GET_THREAD_INFO(a2, a1)
+	l32i	a4, a2, TI_FLAGS
+	_bbci.l	a3, PS_UM_BIT, 6f
 
 	/* Specific to a user exception exit:
 	 * We need to check some flags for signal handling and rescheduling,
@@ -438,9 +439,6 @@ common_exception_return:
 	 * Note that we don't disable interrupts here. 
 	 */
 
-	GET_THREAD_INFO(a2,a1)
-	l32i	a4, a2, TI_FLAGS
-
 	_bbsi.l	a4, TIF_NEED_RESCHED, 3f
 	_bbsi.l	a4, TIF_NOTIFY_RESUME, 2f
 	_bbci.l	a4, TIF_SIGPENDING, 5f
@@ -463,6 +461,19 @@ common_exception_return:
 	callx4	a4
 	j	1b
 
+#ifdef CONFIG_PREEMPT
+6:
+	_bbci.l	a4, TIF_NEED_RESCHED, 4f
+
+	/* Check current_thread_info->preempt_count */
+
+	l32i	a4, a2, TI_PRE_COUNT
+	bnez	a4, 4f
+	movi	a4, preempt_schedule_irq
+	callx4	a4
+	j	1b
+#endif
+
 5:
 #ifdef CONFIG_DEBUG_TLB_SANITY
 	l32i	a4, a1, PT_DEPC
@@ -470,6 +481,7 @@ common_exception_return:
 	movi	a4, check_tlb_sanity
 	callx4	a4
 #endif
+6:
 4:
 #ifdef CONFIG_TRACE_IRQFLAGS
 	l32i	a4, a1, PT_DEPC
@@ -573,29 +585,6 @@ user_exception_exit:
 
 kernel_exception_exit:
 
-#ifdef PREEMPTIBLE_KERNEL
-
-#ifdef CONFIG_PREEMPT
-
-	/*
-	 * Note: We've just returned from a call4, so we have
-	 * at least 4 addt'l regs.
-	 */
-
-	/* Check current_thread_info->preempt_count */
-
-	GET_THREAD_INFO(a2)
-	l32i	a3, a2, TI_PREEMPT
-	bnez	a3, 1f
-
-	l32i	a2, a2, TI_FLAGS
-
-1:
-
-#endif
-
-#endif
-
 	/* Check if we have to do a movsp.
 	 *
 	 * We only have to do a movsp if the previous window-frame has
-- 
1.7.7.6

[PATCH v2 07/11] xtensa: keep a3 and excsave1 on entry to exception handlers

[Max Filippov]

Based on the SMP patch by Joe Taylor and subsequent fixes.
Preserve exception table pointer (normally stored in excsave1 SR) as it
cannot be easily restored in SMP environment.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
---
 arch/xtensa/include/asm/regs.h   |    1 +
 arch/xtensa/kernel/align.S       |    5 +-
 arch/xtensa/kernel/coprocessor.S |    9 +-
 arch/xtensa/kernel/entry.S       |  115 +++++++----------
 arch/xtensa/kernel/vectors.S     |  250 ++++++++++++++++++++++++++++----------
 5 files changed, 238 insertions(+), 142 deletions(-)

diff --git a/arch/xtensa/include/asm/regs.h b/arch/xtensa/include/asm/regs.h
index b24de67..4ba9f51 100644
--- a/arch/xtensa/include/asm/regs.h
+++ b/arch/xtensa/include/asm/regs.h
@@ -82,6 +82,7 @@
 #define PS_CALLINC_SHIFT	16
 #define PS_CALLINC_MASK		0x00030000
 #define PS_OWB_SHIFT		8
+#define PS_OWB_WIDTH		4
 #define PS_OWB_MASK		0x00000F00
 #define PS_RING_SHIFT		6
 #define PS_RING_MASK		0x000000C0
diff --git a/arch/xtensa/kernel/align.S b/arch/xtensa/kernel/align.S
index aa2e87b..d4cef60 100644
--- a/arch/xtensa/kernel/align.S
+++ b/arch/xtensa/kernel/align.S
@@ -146,9 +146,9 @@
  *   a0:	trashed, original value saved on stack (PT_AREG0)
  *   a1:	a1
  *   a2:	new stack pointer, original in DEPC
- *   a3:	dispatch table
+ *   a3:	a3
  *   depc:	a2, original value saved on stack (PT_DEPC)
- *   excsave_1:	a3
+ *   excsave_1:	dispatch table
  *
  *   PT_DEPC >= VALID_DOUBLE_EXCEPTION_ADDRESS: double exception, DEPC
  *	     <  VALID_DOUBLE_EXCEPTION_ADDRESS: regular exception
@@ -171,7 +171,6 @@ ENTRY(fast_unaligned)
 	s32i	a8, a2, PT_AREG8
 
 	rsr	a0, depc
-	xsr	a3, excsave1
 	s32i	a0, a2, PT_AREG2
 	s32i	a3, a2, PT_AREG3
 
diff --git a/arch/xtensa/kernel/coprocessor.S b/arch/xtensa/kernel/coprocessor.S
index 6476574..a482df5 100644
--- a/arch/xtensa/kernel/coprocessor.S
+++ b/arch/xtensa/kernel/coprocessor.S
@@ -32,9 +32,9 @@
  *   a0:	trashed, original value saved on stack (PT_AREG0)
  *   a1:	a1
  *   a2:	new stack pointer, original in DEPC
- *   a3:	dispatch table
+ *   a3:	a3
  *   depc:	a2, original value saved on stack (PT_DEPC)
- *   excsave_1:	a3
+ *   excsave_1:	dispatch table
  *
  *   PT_DEPC >= VALID_DOUBLE_EXCEPTION_ADDRESS: double exception, DEPC
  *	     <  VALID_DOUBLE_EXCEPTION_ADDRESS: regular exception
@@ -225,9 +225,9 @@ ENDPROC(coprocessor_restore)
  *   a0:	trashed, original value saved on stack (PT_AREG0)
  *   a1:	a1
  *   a2:	new stack pointer, original in DEPC
- *   a3:	dispatch table
+ *   a3:	a3
  *   depc:	a2, original value saved on stack (PT_DEPC)
- *   excsave_1:	a3
+ *   excsave_1:	dispatch table
  *
  *   PT_DEPC >= VALID_DOUBLE_EXCEPTION_ADDRESS: double exception, DEPC
  *	     <  VALID_DOUBLE_EXCEPTION_ADDRESS: regular exception
@@ -245,7 +245,6 @@ ENTRY(fast_coprocessor)
 
 	/* Save remaining registers a1-a3 and SAR */
 
-	xsr	a3, excsave1
 	s32i	a3, a2, PT_AREG3
 	rsr	a3, sar
 	s32i	a1, a2, PT_AREG1
diff --git a/arch/xtensa/kernel/entry.S b/arch/xtensa/kernel/entry.S
index 3f3de28..ab025c1 100644
--- a/arch/xtensa/kernel/entry.S
+++ b/arch/xtensa/kernel/entry.S
@@ -91,9 +91,9 @@
  *   a0:	trashed, original value saved on stack (PT_AREG0)
  *   a1:	a1
  *   a2:	new stack pointer, original value in depc
- *   a3:	dispatch table
+ *   a3:	a3
  *   depc:	a2, original value saved on stack (PT_DEPC)
- *   excsave1:	a3
+ *   excsave1:	dispatch table
  *
  *   PT_DEPC >= VALID_DOUBLE_EXCEPTION_ADDRESS: double exception, DEPC
  *	     <  VALID_DOUBLE_EXCEPTION_ADDRESS: regular exception
@@ -109,9 +109,8 @@
 
 ENTRY(user_exception)
 
-	/* Save a2, a3, and depc, restore excsave_1 and set SP. */
+	/* Save a1, a2, a3, and set SP. */
 
-	xsr	a3, excsave1
 	rsr	a0, depc
 	s32i	a1, a2, PT_AREG1
 	s32i	a0, a2, PT_AREG2
@@ -237,9 +236,9 @@ ENDPROC(user_exception)
  *   a0:	trashed, original value saved on stack (PT_AREG0)
  *   a1:	a1
  *   a2:	new stack pointer, original in DEPC
- *   a3:	dispatch table
+ *   a3:	a3
  *   depc:	a2, original value saved on stack (PT_DEPC)
- *   excsave_1:	a3
+ *   excsave_1:	dispatch table
  *
  *   PT_DEPC >= VALID_DOUBLE_EXCEPTION_ADDRESS: double exception, DEPC
  *	     <  VALID_DOUBLE_EXCEPTION_ADDRESS: regular exception
@@ -255,9 +254,8 @@ ENDPROC(user_exception)
 
 ENTRY(kernel_exception)
 
-	/* Save a0, a2, a3, DEPC and set SP. */
+	/* Save a1, a2, a3, and set SP. */
 
-	xsr	a3, excsave1		# restore a3, excsave_1
 	rsr	a0, depc		# get a2
 	s32i	a1, a2, PT_AREG1
 	s32i	a0, a2, PT_AREG2
@@ -408,7 +406,7 @@ common_exception:
 	 * exception handler and call the exception handler.
 	 */
 
-	movi	a4, exc_table
+	rsr	a4, excsave1
 	mov	a6, a1			# pass stack frame
 	mov	a7, a0			# pass EXCCAUSE
 	addx4	a4, a0, a4
@@ -832,9 +830,9 @@ ENDPROC(unrecoverable_exception)
  *   a0:	trashed, original value saved on stack (PT_AREG0)
  *   a1:	a1
  *   a2:	new stack pointer, original in DEPC
- *   a3:	dispatch table
+ *   a3:	a3
  *   depc:	a2, original value saved on stack (PT_DEPC)
- *   excsave_1:	a3
+ *   excsave_1:	dispatch table
  *
  *   PT_DEPC >= VALID_DOUBLE_EXCEPTION_ADDRESS: double exception, DEPC
  *	     <  VALID_DOUBLE_EXCEPTION_ADDRESS: regular exception
@@ -857,18 +855,16 @@ ENTRY(fast_alloca)
 
 	rsr	a0, depc		# get a2
 	s32i	a4, a2, PT_AREG4	# save a4 and
+	s32i	a3, a2, PT_AREG3
 	s32i	a0, a2, PT_AREG2	# a2 to stack
 
 	/* Exit critical section. */
 
 	movi	a0, 0
+	rsr	a3, excsave1
 	s32i	a0, a3, EXC_TABLE_FIXUP
 
-	/* Restore a3, excsave_1 */
-
-	xsr	a3, excsave1		# make sure excsave_1 is valid for dbl.
 	rsr	a4, epc1		# get exception address
-	s32i	a3, a2, PT_AREG3	# save a3 to stack
 
 #ifdef ALLOCA_EXCEPTION_IN_IRAM
 #error	iram not supported
@@ -1007,9 +1003,9 @@ ENDPROC(fast_alloca)
  *   a0:	trashed, original value saved on stack (PT_AREG0)
  *   a1:	a1
  *   a2:	new stack pointer, original in DEPC
- *   a3:	dispatch table
+ *   a3:	a3
  *   depc:	a2, original value saved on stack (PT_DEPC)
- *   excsave_1:	a3
+ *   excsave_1:	dispatch table
  */
 
 ENTRY(fast_syscall_kernel)
@@ -1056,7 +1052,6 @@ ENTRY(fast_syscall_unrecoverable)
 
 	l32i    a0, a2, PT_AREG0        # restore a0
 	xsr     a2, depc                # restore a2, depc
-	rsr     a3, excsave1
 
 	wsr     a0, excsave1
 	movi    a0, unrecoverable_exception
@@ -1078,10 +1073,10 @@ ENDPROC(fast_syscall_unrecoverable)
  *   a0:	a2 (syscall-nr), original value saved on stack (PT_AREG0)
  *   a1:	a1
  *   a2:	new stack pointer, original in a0 and DEPC
- *   a3:	dispatch table, original in excsave_1
+ *   a3:	a3
  *   a4..a15:	unchanged
  *   depc:	a2, original value saved on stack (PT_DEPC)
- *   excsave_1:	a3
+ *   excsave_1:	dispatch table
  *
  *   PT_DEPC >= VALID_DOUBLE_EXCEPTION_ADDRESS: double exception, DEPC
  *	     <  VALID_DOUBLE_EXCEPTION_ADDRESS: regular exception
@@ -1114,8 +1109,6 @@ ENDPROC(fast_syscall_unrecoverable)
 
 ENTRY(fast_syscall_xtensa)
 
-	xsr	a3, excsave1		# restore a3, excsave1
-
 	s32i	a7, a2, PT_AREG7	# we need an additional register
 	movi	a7, 4			# sizeof(unsigned int)
 	access_ok a3, a7, a0, a2, .Leac	# a0: scratch reg, a2: sp
@@ -1178,9 +1171,9 @@ ENDPROC(fast_syscall_xtensa)
  *   a0:	trashed, original value saved on stack (PT_AREG0)
  *   a1:	a1
  *   a2:	new stack pointer, original in DEPC
- *   a3:	dispatch table
+ *   a3:	a3
  *   depc:	a2, original value saved on stack (PT_DEPC)
- *   excsave_1:	a3
+ *   excsave_1:	dispatch table
  *
  * Note: We assume the stack pointer is EXC_TABLE_KSTK in the fixup handler.
  */
@@ -1189,15 +1182,16 @@ ENTRY(fast_syscall_spill_registers)
 
 	/* Register a FIXUP handler (pass current wb as a parameter) */
 
+	xsr	a3, excsave1
 	movi	a0, fast_syscall_spill_registers_fixup
 	s32i	a0, a3, EXC_TABLE_FIXUP
 	rsr	a0, windowbase
 	s32i	a0, a3, EXC_TABLE_PARAM
+	xsr	a3, excsave1		# restore a3 and excsave_1
 
-	/* Save a3 and SAR on stack. */
+	/* Save a3, a4 and SAR on stack. */
 
 	rsr	a0, sar
-	xsr	a3, excsave1		# restore a3 and excsave_1
 	s32i	a3, a2, PT_AREG3
 	s32i	a4, a2, PT_AREG4
 	s32i	a0, a2, PT_AREG5	# store SAR to PT_AREG5
@@ -1251,14 +1245,14 @@ fast_syscall_spill_registers_fixup:
 	 * in WS, so that the exception handlers save them to the task stack.
 	 */
 
-	rsr	a3, excsave1	# get spill-mask
+	xsr	a3, excsave1	# get spill-mask
 	slli	a2, a3, 1	# shift left by one
 
 	slli	a3, a2, 32-WSBITS
 	src	a2, a2, a3	# a1 = xxwww1yyxxxwww1yy......
 	wsr	a2, windowstart	# set corrected windowstart
 
-	movi	a3, exc_table
+	rsr	a3, excsave1
 	l32i	a2, a3, EXC_TABLE_DOUBLE_SAVE	# restore a2
 	l32i	a3, a3, EXC_TABLE_PARAM	# original WB (in user task)
 
@@ -1295,7 +1289,7 @@ fast_syscall_spill_registers_fixup:
 
 	/* Jump to the exception handler. */
 
-	movi	a3, exc_table
+	rsr	a3, excsave1
 	rsr	a0, exccause
 	addx4	a0, a0, a3              	# find entry in table
 	l32i	a0, a0, EXC_TABLE_FAST_USER     # load handler
@@ -1312,6 +1306,7 @@ fast_syscall_spill_registers_fixup_return:
 	xsr	a3, excsave1
 	movi	a2, fast_syscall_spill_registers_fixup
 	s32i	a2, a3, EXC_TABLE_FIXUP
+	s32i	a0, a3, EXC_TABLE_DOUBLE_SAVE
 	rsr	a2, windowbase
 	s32i	a2, a3, EXC_TABLE_PARAM
 	l32i	a2, a3, EXC_TABLE_KSTK
@@ -1323,11 +1318,6 @@ fast_syscall_spill_registers_fixup_return:
 	wsr	a3, windowbase
 	rsync
 
-	/* Restore a3 and return. */
-
-	movi	a3, exc_table
-	xsr	a3, excsave1
-
 	rfde
 
 
@@ -1514,9 +1504,8 @@ ENTRY(_spill_registers)
 
 	movi	a0, 0
 
-	movi	a3, exc_table
+	rsr	a3, excsave1
 	l32i	a1, a3, EXC_TABLE_KSTK
-	wsr	a3, excsave1
 
 	movi	a4, (1 << PS_WOE_BIT) | LOCKLEVEL
 	wsr	a4, ps
@@ -1560,9 +1549,9 @@ ENDPROC(fast_second_level_miss_double_kernel)
  *   a0:	trashed, original value saved on stack (PT_AREG0)
  *   a1:	a1
  *   a2:	new stack pointer, original in DEPC
- *   a3:	dispatch table
+ *   a3:	a3
  *   depc:	a2, original value saved on stack (PT_DEPC)
- *   excsave_1:	a3
+ *   excsave_1:	dispatch table
  *
  *   PT_DEPC >= VALID_DOUBLE_EXCEPTION_ADDRESS: double exception, DEPC
  *	     <  VALID_DOUBLE_EXCEPTION_ADDRESS: regular exception
@@ -1570,9 +1559,10 @@ ENDPROC(fast_second_level_miss_double_kernel)
 
 ENTRY(fast_second_level_miss)
 
-	/* Save a1. Note: we don't expect a double exception. */
+	/* Save a1 and a3. Note: we don't expect a double exception. */
 
 	s32i	a1, a2, PT_AREG1
+	s32i	a3, a2, PT_AREG3
 
 	/* We need to map the page of PTEs for the user task.  Find
 	 * the pointer to that page.  Also, it's possible for tsk->mm
@@ -1594,9 +1584,6 @@ ENTRY(fast_second_level_miss)
 	l32i	a0, a1, TASK_MM		# tsk->mm
 	beqz	a0, 9f
 
-
-	/* We deliberately destroy a3 that holds the exception table. */
-
 8:	rsr	a3, excvaddr		# fault address
 	_PGD_OFFSET(a0, a3, a1)
 	l32i	a0, a0, 0		# read pmdval
@@ -1647,7 +1634,7 @@ ENTRY(fast_second_level_miss)
 
 	/* Exit critical section. */
 
-4:	movi	a3, exc_table		# restore a3
+4:	rsr	a3, excsave1
 	movi	a0, 0
 	s32i	a0, a3, EXC_TABLE_FIXUP
 
@@ -1655,8 +1642,8 @@ ENTRY(fast_second_level_miss)
 
 	l32i	a0, a2, PT_AREG0
 	l32i	a1, a2, PT_AREG1
+	l32i	a3, a2, PT_AREG3
 	l32i	a2, a2, PT_DEPC
-	xsr	a3, excsave1
 
 	bgeui	a2, VALID_DOUBLE_EXCEPTION_ADDRESS, 1f
 
@@ -1743,11 +1730,8 @@ ENTRY(fast_second_level_miss)
 
 2:	/* Invalid PGD, default exception handling */
 
-	movi	a3, exc_table
 	rsr	a1, depc
-	xsr	a3, excsave1
 	s32i	a1, a2, PT_AREG2
-	s32i	a3, a2, PT_AREG3
 	mov	a1, a2
 
 	rsr	a2, ps
@@ -1767,9 +1751,9 @@ ENDPROC(fast_second_level_miss)
  *   a0:	trashed, original value saved on stack (PT_AREG0)
  *   a1:	a1
  *   a2:	new stack pointer, original in DEPC
- *   a3:	dispatch table
+ *   a3:	a3
  *   depc:	a2, original value saved on stack (PT_DEPC)
- *   excsave_1:	a3
+ *   excsave_1:	dispatch table
  *
  *   PT_DEPC >= VALID_DOUBLE_EXCEPTION_ADDRESS: double exception, DEPC
  *	     <  VALID_DOUBLE_EXCEPTION_ADDRESS: regular exception
@@ -1777,17 +1761,17 @@ ENDPROC(fast_second_level_miss)
 
 ENTRY(fast_store_prohibited)
 
-	/* Save a1 and a4. */
+	/* Save a1 and a3. */
 
 	s32i	a1, a2, PT_AREG1
-	s32i	a4, a2, PT_AREG4
+	s32i	a3, a2, PT_AREG3
 
 	GET_CURRENT(a1,a2)
 	l32i	a0, a1, TASK_MM		# tsk->mm
 	beqz	a0, 9f
 
 8:	rsr	a1, excvaddr		# fault address
-	_PGD_OFFSET(a0, a1, a4)
+	_PGD_OFFSET(a0, a1, a3)
 	l32i	a0, a0, 0
 	beqz	a0, 2f
 
@@ -1796,39 +1780,37 @@ ENTRY(fast_store_prohibited)
 	 * and is not PAGE_NONE. See pgtable.h for possible PTE layouts.
 	 */
 
-	_PTE_OFFSET(a0, a1, a4)
-	l32i	a4, a0, 0		# read pteval
+	_PTE_OFFSET(a0, a1, a3)
+	l32i	a3, a0, 0		# read pteval
 	movi	a1, _PAGE_CA_INVALID
-	ball	a4, a1, 2f
-	bbci.l	a4, _PAGE_WRITABLE_BIT, 2f
+	ball	a3, a1, 2f
+	bbci.l	a3, _PAGE_WRITABLE_BIT, 2f
 
 	movi	a1, _PAGE_ACCESSED | _PAGE_DIRTY | _PAGE_HW_WRITE
-	or	a4, a4, a1
+	or	a3, a3, a1
 	rsr	a1, excvaddr
-	s32i	a4, a0, 0
+	s32i	a3, a0, 0
 
 	/* We need to flush the cache if we have page coloring. */
 #if (DCACHE_WAY_SIZE > PAGE_SIZE) && XCHAL_DCACHE_IS_WRITEBACK
 	dhwb	a0, 0
 #endif
 	pdtlb	a0, a1
-	wdtlb	a4, a0
+	wdtlb	a3, a0
 
 	/* Exit critical section. */
 
 	movi	a0, 0
+	rsr	a3, excsave1
 	s32i	a0, a3, EXC_TABLE_FIXUP
 
 	/* Restore the working registers, and return. */
 
-	l32i	a4, a2, PT_AREG4
+	l32i	a3, a2, PT_AREG3
 	l32i	a1, a2, PT_AREG1
 	l32i	a0, a2, PT_AREG0
 	l32i	a2, a2, PT_DEPC
 
-	/* Restore excsave1 and a3. */
-
-	xsr	a3, excsave1
 	bgeui	a2, VALID_DOUBLE_EXCEPTION_ADDRESS, 1f
 
 	rsr	a2, depc
@@ -1845,11 +1827,8 @@ ENTRY(fast_store_prohibited)
 
 2:	/* If there was a problem, handle fault in C */
 
-	rsr	a4, depc	# still holds a2
-	xsr	a3, excsave1
-	s32i	a4, a2, PT_AREG2
-	s32i	a3, a2, PT_AREG3
-	l32i	a4, a2, PT_AREG4
+	rsr	a3, depc	# still holds a2
+	s32i	a3, a2, PT_AREG2
 	mov	a1, a2
 
 	rsr	a2, ps
diff --git a/arch/xtensa/kernel/vectors.S b/arch/xtensa/kernel/vectors.S
index f9e1753..cb8fd44 100644
--- a/arch/xtensa/kernel/vectors.S
+++ b/arch/xtensa/kernel/vectors.S
@@ -78,6 +78,7 @@ ENTRY(_UserExceptionVector)
 	s32i	a0, a2, PT_DEPC		# mark it as a regular exception
 	addx4	a0, a0, a3		# find entry in table
 	l32i	a0, a0, EXC_TABLE_FAST_USER	# load handler
+	xsr	a3, excsave1		# restore a3 and dispatch table
 	jx	a0
 
 ENDPROC(_UserExceptionVector)
@@ -104,6 +105,7 @@ ENTRY(_KernelExceptionVector)
 	s32i	a0, a2, PT_DEPC		# mark it as a regular exception
 	addx4	a0, a0, a3		# find entry in table
 	l32i	a0, a0, EXC_TABLE_FAST_KERNEL	# load handler address
+	xsr	a3, excsave1		# restore a3 and dispatch table
 	jx	a0
 
 ENDPROC(_KernelExceptionVector)
@@ -168,7 +170,7 @@ ENDPROC(_KernelExceptionVector)
  *
  *	a0:	   DEPC
  *	a1: 	   a1
- *	a2:	   trashed, original value in EXC_TABLE_DOUBLE_A2
+ *	a2:	   trashed, original value in EXC_TABLE_DOUBLE_SAVE
  *	a3:	   exctable
  *	depc:	   a0
  *	excsave_1: a3
@@ -204,47 +206,46 @@ ENDPROC(_KernelExceptionVector)
 
 	.section .DoubleExceptionVector.text, "ax"
 	.begin literal_prefix .DoubleExceptionVector
+	.globl _DoubleExceptionVector_WindowUnderflow
+	.globl _DoubleExceptionVector_WindowOverflow
 
 ENTRY(_DoubleExceptionVector)
 
-	/* Deliberately destroy excsave (don't assume it's value was valid). */
-
-	wsr	a3, excsave1		# save a3
+	xsr	a3, excsave1
+	s32i	a2, a3, EXC_TABLE_DOUBLE_SAVE
 
 	/* Check for kernel double exception (usually fatal). */
 
-	rsr	a3, ps
-	_bbci.l	a3, PS_UM_BIT, .Lksp
+	rsr	a2, ps
+	_bbci.l	a2, PS_UM_BIT, .Lksp
 
 	/* Check if we are currently handling a window exception. */
 	/* Note: We don't need to indicate that we enter a critical section. */
 
 	xsr	a0, depc		# get DEPC, save a0
 
-	movi	a3, WINDOW_VECTORS_VADDR
-	_bltu	a0, a3, .Lfixup
-	addi	a3, a3, WINDOW_VECTORS_SIZE
-	_bgeu	a0, a3, .Lfixup
+	movi	a2, WINDOW_VECTORS_VADDR
+	_bltu	a0, a2, .Lfixup
+	addi	a2, a2, WINDOW_VECTORS_SIZE
+	_bgeu	a0, a2, .Lfixup
 
 	/* Window overflow/underflow exception. Get stack pointer. */
 
-	mov	a3, a2
-	/* This explicit literal and the following references to it are made
-	 * in order to fit DoubleExceptionVector.literals into the available
-	 * 16-byte gap before DoubleExceptionVector.text in the absence of
-	 * link time relaxation. See kernel/vmlinux.lds.S
-	 */
-	.literal .Lexc_table, exc_table
-	l32r	a2, .Lexc_table
-	l32i	a2, a2, EXC_TABLE_KSTK
+	l32i	a2, a3, EXC_TABLE_KSTK
 
 	/* Check for overflow/underflow exception, jump if overflow. */
 
-	_bbci.l	a0, 6, .Lovfl
-
-	/* a0: depc, a1: a1, a2: kstk, a3: a2, depc: a0, excsave: a3  */
+	_bbci.l	a0, 6, _DoubleExceptionVector_WindowOverflow
 
-	/* Restart window underflow exception.
+	/*
+	 * Restart window underflow exception.
+	 * Currently:
+	 *	depc = orig a0,
+	 *	a0 = orig DEPC,
+	 *	a2 = new sp based on KSTK from exc_table
+	 *	a3 = excsave_1
+	 *	excsave_1 = orig a3
+	 *
 	 * We return to the instruction in user space that caused the window
 	 * underflow exception. Therefore, we change window base to the value
 	 * before we entered the window underflow exception and prepare the
@@ -252,10 +253,11 @@ ENTRY(_DoubleExceptionVector)
 	 * by changing depc (in a0).
 	 * Note: We can trash the current window frame (a0...a3) and depc!
 	 */
-
+_DoubleExceptionVector_WindowUnderflow:
+	xsr	a3, excsave1
 	wsr	a2, depc		# save stack pointer temporarily
 	rsr	a0, ps
-	extui	a0, a0, PS_OWB_SHIFT, 4
+	extui	a0, a0, PS_OWB_SHIFT, PS_OWB_WIDTH
 	wsr	a0, windowbase
 	rsync
 
@@ -263,28 +265,57 @@ ENTRY(_DoubleExceptionVector)
 
 	xsr	a2, depc		# save a2 and get stack pointer
 	s32i	a0, a2, PT_AREG0
-
-	wsr	a3, excsave1		# save a3
-	l32r	a3, .Lexc_table
-
+	xsr	a3, excsave1
 	rsr	a0, exccause
 	s32i	a0, a2, PT_DEPC		# mark it as a regular exception
 	addx4	a0, a0, a3
+	xsr	a3, excsave1
 	l32i	a0, a0, EXC_TABLE_FAST_USER
 	jx	a0
 
-.Lfixup:/* Check for a fixup handler or if we were in a critical section. */
+	/*
+	 * We only allow the ITLB miss exception if we are in kernel space.
+	 * All other exceptions are unexpected and thus unrecoverable!
+	 */
+
+#ifdef CONFIG_MMU
+	.extern fast_second_level_miss_double_kernel
+
+.Lksp:	/* a0: a0, a1: a1, a2: a2, a3: trashed, depc: depc, excsave: a3 */
+
+	rsr	a3, exccause
+	beqi	a3, EXCCAUSE_ITLB_MISS, 1f
+	addi	a3, a3, -EXCCAUSE_DTLB_MISS
+	bnez	a3, .Lunrecoverable
+1:	movi	a3, fast_second_level_miss_double_kernel
+	jx	a3
+#else
+.equ	.Lksp,	.Lunrecoverable
+#endif
+
+	/* Critical! We can't handle this situation. PANIC! */
 
-	/* a0: depc, a1: a1, a2: a2, a3: trashed, depc: a0, excsave1: a3 */
+	.extern unrecoverable_exception
 
-	l32r	a3, .Lexc_table
-	s32i	a2, a3, EXC_TABLE_DOUBLE_SAVE	# temporary variable
+.Lunrecoverable_fixup:
+	l32i	a2, a3, EXC_TABLE_DOUBLE_SAVE
+	xsr	a0, depc
+
+.Lunrecoverable:
+	rsr	a3, excsave1
+	wsr	a0, excsave1
+	movi	a0, unrecoverable_exception
+	callx0	a0
+
+.Lfixup:/* Check for a fixup handler or if we were in a critical section. */
+
+	/* a0: depc, a1: a1, a2: trash, a3: exctable, depc: a0, excsave1: a3 */
 
 	/* Enter critical section. */
 
 	l32i	a2, a3, EXC_TABLE_FIXUP
 	s32i	a3, a3, EXC_TABLE_FIXUP
-	beq	a2, a3, .Lunrecoverable_fixup	# critical!
+	beq	a2, a3, .Lunrecoverable_fixup	# critical section
 	beqz	a2, .Ldflt			# no handler was registered
 
 	/* a0: depc, a1: a1, a2: trash, a3: exctable, depc: a0, excsave: a3 */
@@ -293,58 +324,145 @@ ENTRY(_DoubleExceptionVector)
 
 .Ldflt:	/* Get stack pointer. */
 
-	l32i	a3, a3, EXC_TABLE_DOUBLE_SAVE
-	addi	a2, a3, -PT_USER_SIZE
-
-.Lovfl:	/* Jump to default handlers. */
+	l32i	a2, a3, EXC_TABLE_DOUBLE_SAVE
+	addi	a2, a2, -PT_USER_SIZE
 
-	/* a0: depc, a1: a1, a2: kstk, a3: a2, depc: a0, excsave: a3 */
+	/* a0: depc, a1: a1, a2: kstk, a3: exctable, depc: a0, excsave: a3 */
 
-	xsr	a3, depc
 	s32i	a0, a2, PT_DEPC
-	s32i	a3, a2, PT_AREG0
+	l32i	a0, a3, EXC_TABLE_DOUBLE_SAVE
+	xsr	a0, depc
+	s32i	a0, a2, PT_AREG0
 
-	/* a0: avail, a1: a1, a2: kstk, a3: avail, depc: a2, excsave: a3 */
+	/* a0: avail, a1: a1, a2: kstk, a3: exctable, depc: a2, excsave: a3 */
 
-	l32r	a3, .Lexc_table
 	rsr	a0, exccause
 	addx4	a0, a0, a3
+	xsr	a3, excsave1
 	l32i	a0, a0, EXC_TABLE_FAST_USER
 	jx	a0
 
 	/*
-	 * We only allow the ITLB miss exception if we are in kernel space.
-	 * All other exceptions are unexpected and thus unrecoverable!
+	 * Restart window OVERFLOW exception.
+	 * Currently:
+	 *	depc = orig a0,
+	 *	a0 = orig DEPC,
+	 *	a2 = new sp based on KSTK from exc_table
+	 *	a3 = EXCSAVE_1
+	 *	excsave_1 = orig a3
+	 *
+	 * We return to the instruction in user space that caused the window
+	 * overflow exception. Therefore, we change window base to the value
+	 * before we entered the window overflow exception and prepare the
+	 * registers to return as if we were coming from a regular exception
+	 * by changing DEPC (in a0).
+	 *
+	 * NOTE: We CANNOT trash the current window frame (a0...a3), but we
+	 * can clobber depc.
+	 *
+	 * The tricky part here is that overflow8 and overflow12 handlers
+	 * save a0, then clobber a0.  To restart the handler, we have to restore
+	 * a0 if the double exception was past the point where a0 was clobbered.
+	 *
+	 * To keep things simple, we take advantage of the fact all overflow
+	 * handlers save a0 in their very first instruction.  If DEPC was past
+	 * that instruction, we can safely restore a0 from where it was saved
+	 * on the stack.
+	 *
+	 * a0: depc, a1: a1, a2: kstk, a3: exc_table, depc: a0, excsave1: a3
 	 */
+_DoubleExceptionVector_WindowOverflow:
+	extui	a2, a0, 0, 6	# get offset into 64-byte vector handler
+	beqz	a2, 1f		# if at start of vector, don't restore
 
-#ifdef CONFIG_MMU
-	.extern fast_second_level_miss_double_kernel
+	addi	a0, a0, -128
+	bbsi	a0, 8, 1f	# don't restore except for overflow 8 and 12
+	bbsi	a0, 7, 2f
 
-.Lksp:	/* a0: a0, a1: a1, a2: a2, a3: trashed, depc: depc, excsave: a3 */
+	/*
+	 * Restore a0 as saved by _WindowOverflow8().
+	 *
+	 * FIXME:  we really need a fixup handler for this L32E,
+	 * for the extremely unlikely case where the overflow handler's
+	 * reference thru a0 gets a hardware TLB refill that bumps out
+	 * the (distinct, aliasing) TLB entry that mapped its prior
+	 * references thru a9, and where our reference now thru a9
+	 * gets a 2nd-level miss exception (not hardware TLB refill).
+	 */
 
-	rsr	a3, exccause
-	beqi	a3, EXCCAUSE_ITLB_MISS, 1f
-	addi	a3, a3, -EXCCAUSE_DTLB_MISS
-	bnez	a3, .Lunrecoverable
-1:	movi	a3, fast_second_level_miss_double_kernel
-	jx	a3
-#else
-.equ	.Lksp,	.Lunrecoverable
-#endif
+	l32e	a2, a9, -16
+	wsr	a2, depc	# replace the saved a0
+	j	1f
 
-	/* Critical! We can't handle this situation. PANIC! */
+2:
+	/*
+	 * Restore a0 as saved by _WindowOverflow12().
+	 *
+	 * FIXME:  we really need a fixup handler for this L32E,
+	 * for the extremely unlikely case where the overflow handler's
+	 * reference thru a0 gets a hardware TLB refill that bumps out
+	 * the (distinct, aliasing) TLB entry that mapped its prior
+	 * references thru a13, and where our reference now thru a13
+	 * gets a 2nd-level miss exception (not hardware TLB refill).
+	 */
 
-	.extern unrecoverable_exception
+	l32e	a2, a13, -16
+	wsr	a2, depc	# replace the saved a0
+1:
+	/*
+	 * Restore WindowBase while leaving all address registers restored.
+	 * We have to use ROTW for this, because WSR.WINDOWBASE requires
+	 * an address register (which would prevent restore).
+	 *
+	 * Window Base goes from 0 ... 7 (Module 8)
+	 * Window Start is 8 bits; Ex: (0b1010 1010):0x55 from series of call4s
+	 */
+
+	rsr	a0, ps
+	extui	a0, a0, PS_OWB_SHIFT, PS_OWB_WIDTH
+	rsr	a2, windowbase
+	sub	a0, a2, a0
+	extui	a0, a0, 0, 3
 
-.Lunrecoverable_fixup:
 	l32i	a2, a3, EXC_TABLE_DOUBLE_SAVE
-	xsr	a0, depc
+	xsr	a3, excsave1
+	beqi	a0, 1, .L1pane
+	beqi	a0, 3, .L3pane
 
-.Lunrecoverable:
-	rsr	a3, excsave1
-	wsr	a0, excsave1
-	movi	a0, unrecoverable_exception
-	callx0	a0
+	rsr	a0, depc
+	rotw	-2
+
+	/*
+	 * We are now in the user code's original window frame.
+	 * Process the exception as a user exception as if it was
+	 * taken by the user code.
+	 *
+	 * This is similar to the user exception vector,
+	 * except that PT_DEPC isn't set to EXCCAUSE.
+	 */
+1:
+	xsr	a3, excsave1
+	wsr	a2, depc
+	l32i	a2, a3, EXC_TABLE_KSTK
+	s32i	a0, a2, PT_AREG0
+	rsr	a0, exccause
+
+	s32i	a0, a2, PT_DEPC
+
+	addx4	a0, a0, a3
+	l32i	a0, a0, EXC_TABLE_FAST_USER
+	xsr	a3, excsave1
+	jx	a0
+
+.L1pane:
+	rsr	a0, depc
+	rotw	-1
+	j	1b
+
+.L3pane:
+	rsr	a0, depc
+	rotw	-3
+	j	1b
 
 	.end literal_prefix
 
-- 
1.7.7.6

[PATCH v2 08/11] xtensa: new fast_alloca handler

[Max Filippov]

Instead of emulating movsp instruction in the kernel use window
underflow handler to load missing register window and retry failed
movsp.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
---
 arch/xtensa/kernel/entry.S |  192 +++++++++----------------------------------
 1 files changed, 40 insertions(+), 152 deletions(-)

diff --git a/arch/xtensa/kernel/entry.S b/arch/xtensa/kernel/entry.S
index ab025c1..de1dfa1 100644
--- a/arch/xtensa/kernel/entry.S
+++ b/arch/xtensa/kernel/entry.S
@@ -31,7 +31,6 @@
 /* Unimplemented features. */
 
 #undef KERNEL_STACK_OVERFLOW_CHECK
-#undef ALLOCA_EXCEPTION_IN_IRAM
 
 /* Not well tested.
  *
@@ -819,11 +818,27 @@ ENDPROC(unrecoverable_exception)
  *
  *  The ALLOCA handler is entered when user code executes the MOVSP
  *  instruction and the caller's frame is not in the register file.
- *  In this case, the caller frame's a0..a3 are on the stack just
- *  below sp (a1), and this handler moves them.
  *
- *  For "MOVSP <ar>,<as>" without destination register a1, this routine
- *  simply moves the value from <as> to <ar> without moving the save area.
+ * This algorithm was taken from the Ross Morley's RTOS Porting Layer:
+ *
+ *    /home/ross/rtos/porting/XtensaRTOS-PortingLayer-20090507/xtensa_vectors.S
+ *
+ * It leverages the existing window spill/fill routines and their support for
+ * double exceptions. The 'movsp' instruction will only cause an exception if
+ * the next window needs to be loaded. In fact this ALLOCA exception may be
+ * replaced at some point by changing the hardware to do a underflow exception
+ * of the proper size instead.
+ *
+ * This algorithm simply backs out the register changes started by the user
+ * excpetion handler, makes it appear that we have started a window underflow
+ * by rotating the window back and then setting the old window base (OWB) in
+ * the 'ps' register with the rolled back window base. The 'movsp' instruction
+ * will be re-executed and this time since the next window frames is in the
+ * active AR registers it won't cause an exception.
+ *
+ * If the WindowUnderflow code gets a TLB miss the page will get mapped
+ * the the partial windeowUnderflow will be handeled in the double exception
+ * handler.
  *
  * Entry condition:
  *
@@ -838,155 +853,28 @@ ENDPROC(unrecoverable_exception)
  *	     <  VALID_DOUBLE_EXCEPTION_ADDRESS: regular exception
  */
 
-#if XCHAL_HAVE_BE
-#define _EXTUI_MOVSP_SRC(ar)	extui ar, ar, 4, 4
-#define _EXTUI_MOVSP_DST(ar)	extui ar, ar, 0, 4
-#else
-#define _EXTUI_MOVSP_SRC(ar)	extui ar, ar, 0, 4
-#define _EXTUI_MOVSP_DST(ar)	extui ar, ar, 4, 4
-#endif
-
 ENTRY(fast_alloca)
+	rsr	a0, windowbase
+	rotw	-1
+	rsr	a2, ps
+	extui	a3, a2, PS_OWB_SHIFT, PS_OWB_WIDTH
+	xor	a3, a3, a4
+	l32i	a4, a6, PT_AREG0
+	l32i	a1, a6, PT_DEPC
+	rsr	a6, depc
+	wsr	a1, depc
+	slli	a3, a3, PS_OWB_SHIFT
+	xor	a2, a2, a3
+	wsr	a2, ps
+	rsync
 
-	/* We shouldn't be in a double exception. */
-
-	l32i	a0, a2, PT_DEPC
-	_bgeui	a0, VALID_DOUBLE_EXCEPTION_ADDRESS, .Lunhandled_double
-
-	rsr	a0, depc		# get a2
-	s32i	a4, a2, PT_AREG4	# save a4 and
-	s32i	a3, a2, PT_AREG3
-	s32i	a0, a2, PT_AREG2	# a2 to stack
-
-	/* Exit critical section. */
-
-	movi	a0, 0
-	rsr	a3, excsave1
-	s32i	a0, a3, EXC_TABLE_FIXUP
-
-	rsr	a4, epc1		# get exception address
-
-#ifdef ALLOCA_EXCEPTION_IN_IRAM
-#error	iram not supported
-#else
-	/* Note: l8ui not allowed in IRAM/IROM!! */
-	l8ui	a0, a4, 1		# read as(src) from MOVSP instruction
-#endif
-	movi	a3, .Lmovsp_src
-	_EXTUI_MOVSP_SRC(a0)		# extract source register number
-	addx8	a3, a0, a3
-	jx	a3
-
-.Lunhandled_double:
-	wsr	a0, excsave1
-	movi	a0, unrecoverable_exception
-	callx0	a0
-
-	.align 8
-.Lmovsp_src:
-	l32i	a3, a2, PT_AREG0;	_j 1f;	.align 8
-	mov	a3, a1;			_j 1f;	.align 8
-	l32i	a3, a2, PT_AREG2;	_j 1f;	.align 8
-	l32i	a3, a2, PT_AREG3;	_j 1f;	.align 8
-	l32i	a3, a2, PT_AREG4;	_j 1f;	.align 8
-	mov	a3, a5;			_j 1f;	.align 8
-	mov	a3, a6;			_j 1f;	.align 8
-	mov	a3, a7;			_j 1f;	.align 8
-	mov	a3, a8;			_j 1f;	.align 8
-	mov	a3, a9;			_j 1f;	.align 8
-	mov	a3, a10;		_j 1f;	.align 8
-	mov	a3, a11;		_j 1f;	.align 8
-	mov	a3, a12;		_j 1f;	.align 8
-	mov	a3, a13;		_j 1f;	.align 8
-	mov	a3, a14;		_j 1f;	.align 8
-	mov	a3, a15;		_j 1f;	.align 8
-
-1:
-
-#ifdef ALLOCA_EXCEPTION_IN_IRAM
-#error	iram not supported
-#else
-	l8ui	a0, a4, 0		# read ar(dst) from MOVSP instruction
-#endif
-	addi	a4, a4, 3		# step over movsp
-	_EXTUI_MOVSP_DST(a0)		# extract destination register
-	wsr	a4, epc1		# save new epc_1
-
-	_bnei	a0, 1, 1f		# no 'movsp a1, ax': jump
-
-	/* Move the save area. This implies the use of the L32E
-	 * and S32E instructions, because this move must be done with
-	 * the user's PS.RING privilege levels, not with ring 0
-	 * (kernel's) privileges currently active with PS.EXCM
-	 * set. Note that we have stil registered a fixup routine with the
-	 * double exception vector in case a double exception occurs.
-	 */
-
-	/* a0,a4:avail a1:old user stack a2:exc. stack a3:new user stack. */
-
-	l32e	a0, a1, -16
-	l32e	a4, a1, -12
-	s32e	a0, a3, -16
-	s32e	a4, a3, -12
-	l32e	a0, a1, -8
-	l32e	a4, a1, -4
-	s32e	a0, a3, -8
-	s32e	a4, a3, -4
-
-	/* Restore stack-pointer and all the other saved registers. */
-
-	mov	a1, a3
-
-	l32i	a4, a2, PT_AREG4
-	l32i	a3, a2, PT_AREG3
-	l32i	a0, a2, PT_AREG0
-	l32i	a2, a2, PT_AREG2
-	rfe
-
-	/*  MOVSP <at>,<as>  was invoked with <at> != a1.
-	 *  Because the stack pointer is not being modified,
-	 *  we should be able to just modify the pointer
-	 *  without moving any save area.
-	 *  The processor only traps these occurrences if the
-	 *  caller window isn't live, so unfortunately we can't
-	 *  use this as an alternate trap mechanism.
-	 *  So we just do the move.  This requires that we
-	 *  resolve the destination register, not just the source,
-	 *  so there's some extra work.
-	 *  (PERHAPS NOT REALLY NEEDED, BUT CLEANER...)
-	 */
-
-	/* a0 dst-reg, a1 user-stack, a2 stack, a3 value of src reg. */
-
-1:	movi	a4, .Lmovsp_dst
-	addx8	a4, a0, a4
-	jx	a4
-
-	.align 8
-.Lmovsp_dst:
-	s32i	a3, a2, PT_AREG0;	_j 1f;	.align 8
-	mov	a1, a3;			_j 1f;	.align 8
-	s32i	a3, a2, PT_AREG2;	_j 1f;	.align 8
-	s32i	a3, a2, PT_AREG3;	_j 1f;	.align 8
-	s32i	a3, a2, PT_AREG4;	_j 1f;	.align 8
-	mov	a5, a3;			_j 1f;	.align 8
-	mov	a6, a3;			_j 1f;	.align 8
-	mov	a7, a3;			_j 1f;	.align 8
-	mov	a8, a3;			_j 1f;	.align 8
-	mov	a9, a3;			_j 1f;	.align 8
-	mov	a10, a3;		_j 1f;	.align 8
-	mov	a11, a3;		_j 1f;	.align 8
-	mov	a12, a3;		_j 1f;	.align 8
-	mov	a13, a3;		_j 1f;	.align 8
-	mov	a14, a3;		_j 1f;	.align 8
-	mov	a15, a3;		_j 1f;	.align 8
-
-1:	l32i	a4, a2, PT_AREG4
-	l32i	a3, a2, PT_AREG3
-	l32i	a0, a2, PT_AREG0
-	l32i	a2, a2, PT_AREG2
-	rfe
-
+	_bbci.l	a4, 31, 4f
+	rotw	-1
+	_bbci.l	a8, 30, 8f
+	rotw	-1
+	j	_WindowUnderflow12
+8:	j	_WindowUnderflow8
+4:	j	_WindowUnderflow4
 ENDPROC(fast_alloca)
 
 /*
-- 
1.7.7.6

[PATCH v2 09/11] xtensa: don't use echo -e needlessly

[Max Filippov]

-e is not needed to output strings without escape sequences. This breaks
big endian FSF build when the shell is dash, because its builtin echo
doesn't understand '-e' switch and outputs it in the echoed string.

Reported-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
---
 arch/xtensa/Makefile      |    4 ++--
 arch/xtensa/boot/Makefile |    2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/xtensa/Makefile b/arch/xtensa/Makefile
index 136224b..81250ec 100644
--- a/arch/xtensa/Makefile
+++ b/arch/xtensa/Makefile
@@ -55,10 +55,10 @@ ifneq ($(CONFIG_LD_NO_RELAX),)
 LDFLAGS := --no-relax
 endif
 
-ifeq ($(shell echo -e __XTENSA_EB__ | $(CC) -E - | grep -v "\#"),1)
+ifeq ($(shell echo __XTENSA_EB__ | $(CC) -E - | grep -v "\#"),1)
 CHECKFLAGS += -D__XTENSA_EB__
 endif
-ifeq ($(shell echo -e __XTENSA_EL__ | $(CC) -E - | grep -v "\#"),1)
+ifeq ($(shell echo __XTENSA_EL__ | $(CC) -E - | grep -v "\#"),1)
 CHECKFLAGS += -D__XTENSA_EL__
 endif
 
diff --git a/arch/xtensa/boot/Makefile b/arch/xtensa/boot/Makefile
index 64ffc4b..ca20a89 100644
--- a/arch/xtensa/boot/Makefile
+++ b/arch/xtensa/boot/Makefile
@@ -12,7 +12,7 @@
 KBUILD_CFLAGS	+= -fno-builtin -Iarch/$(ARCH)/boot/include
 HOSTFLAGS	+= -Iarch/$(ARCH)/boot/include
 
-BIG_ENDIAN	:= $(shell echo -e __XTENSA_EB__ | $(CC) -E - | grep -v "\#")
+BIG_ENDIAN	:= $(shell echo __XTENSA_EB__ | $(CC) -E - | grep -v "\#")
 
 export ccflags-y
 export BIG_ENDIAN
-- 
1.7.7.6

[PATCH v2 10/11] xtensa: fix !CONFIG_XTENSA_CALIBRATE_CCOUNT build failure

[Max Filippov]

From: Baruch Siach <baruch@tkos.co.il>

Commits 925f5532 (xtensa: ccount based clockevent implementation) and e3f43291
(xtensa: ccount based sched_clock) introduced users of ccount_freq. This
variable doesn't exist when CONFIG_XTENSA_CALIBRATE_CCOUNT is disabled. Add
ccount_freq definition in this case.

Reported-by: Chen Gang <gang.chen@asianux.com>
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
---
 arch/xtensa/include/asm/timex.h |    5 -----
 arch/xtensa/kernel/time.c       |    4 ++--
 2 files changed, 2 insertions(+), 7 deletions(-)

diff --git a/arch/xtensa/include/asm/timex.h b/arch/xtensa/include/asm/timex.h
index 69f9017..86aca77 100644
--- a/arch/xtensa/include/asm/timex.h
+++ b/arch/xtensa/include/asm/timex.h
@@ -35,13 +35,8 @@
 # error "Bad timer number for Linux configurations!"
 #endif
 
-#ifdef CONFIG_XTENSA_CALIBRATE_CCOUNT
 extern unsigned long ccount_freq;
 #define CCOUNT_PER_JIFFY (ccount_freq / HZ)
-#else
-#define CCOUNT_PER_JIFFY (CONFIG_XTENSA_CPU_CLOCK*(1000000UL/HZ))
-#endif
-
 
 typedef unsigned long long cycles_t;
 
diff --git a/arch/xtensa/kernel/time.c b/arch/xtensa/kernel/time.c
index 24bb0c17..a65cb38 100644
--- a/arch/xtensa/kernel/time.c
+++ b/arch/xtensa/kernel/time.c
@@ -29,9 +29,7 @@
 #include <asm/timex.h>
 #include <asm/platform.h>
 
-#ifdef CONFIG_XTENSA_CALIBRATE_CCOUNT
 unsigned long ccount_freq;		/* ccount Hz */
-#endif
 
 static cycle_t ccount_read(struct clocksource *cs)
 {
@@ -129,6 +127,8 @@ void __init time_init(void)
 	platform_calibrate_ccount();
 	printk("%d.%02d MHz\n", (int)ccount_freq/1000000,
 			(int)(ccount_freq/10000)%100);
+#else
+	ccount_freq = CONFIG_XTENSA_CPU_CLOCK*1000000UL;
 #endif
 	clocksource_register_hz(&ccount_clocksource, CCOUNT_PER_JIFFY * HZ);
 
-- 
1.7.7.6

[PATCH v2 11/11] xtensa: remove CCOUNT_PER_JIFFY

[Max Filippov]

From: Baruch Siach <baruch@tkos.co.il>

Use ccount_freq directly to make the code a little more readable.

Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
---
 arch/xtensa/include/asm/timex.h |    1 -
 arch/xtensa/kernel/setup.c      |    4 ++--
 arch/xtensa/kernel/time.c       |    4 ++--
 3 files changed, 4 insertions(+), 5 deletions(-)

diff --git a/arch/xtensa/include/asm/timex.h b/arch/xtensa/include/asm/timex.h
index 86aca77..27fa3c1 100644
--- a/arch/xtensa/include/asm/timex.h
+++ b/arch/xtensa/include/asm/timex.h
@@ -36,7 +36,6 @@
 #endif
 
 extern unsigned long ccount_freq;
-#define CCOUNT_PER_JIFFY (ccount_freq / HZ)
 
 typedef unsigned long long cycles_t;
 
diff --git a/arch/xtensa/kernel/setup.c b/arch/xtensa/kernel/setup.c
index 42a8bba..4a8f027 100644
--- a/arch/xtensa/kernel/setup.c
+++ b/arch/xtensa/kernel/setup.c
@@ -585,8 +585,8 @@ c_show(struct seq_file *f, void *slot)
 		     "bogomips\t: %lu.%02lu\n",
 		     XCHAL_BUILD_UNIQUE_ID,
 		     XCHAL_HAVE_BE ?  "big" : "little",
-		     CCOUNT_PER_JIFFY/(1000000/HZ),
-		     (CCOUNT_PER_JIFFY/(10000/HZ)) % 100,
+		     ccount_freq/1000000,
+		     (ccount_freq/10000) % 100,
 		     loops_per_jiffy/(500000/HZ),
 		     (loops_per_jiffy/(5000/HZ)) % 100);
 
diff --git a/arch/xtensa/kernel/time.c b/arch/xtensa/kernel/time.c
index a65cb38..9af3dd8 100644
--- a/arch/xtensa/kernel/time.c
+++ b/arch/xtensa/kernel/time.c
@@ -130,7 +130,7 @@ void __init time_init(void)
 #else
 	ccount_freq = CONFIG_XTENSA_CPU_CLOCK*1000000UL;
 #endif
-	clocksource_register_hz(&ccount_clocksource, CCOUNT_PER_JIFFY * HZ);
+	clocksource_register_hz(&ccount_clocksource, ccount_freq);
 
 	ccount_timer.evt.cpumask = cpumask_of(0);
 	ccount_timer.evt.irq = irq_create_mapping(NULL, LINUX_TIMER_INT);
@@ -164,7 +164,7 @@ irqreturn_t timer_interrupt (int irq, void *dev_id)
 #ifndef CONFIG_GENERIC_CALIBRATE_DELAY
 void calibrate_delay(void)
 {
-	loops_per_jiffy = CCOUNT_PER_JIFFY;
+	loops_per_jiffy = ccount_freq / HZ;
 	printk("Calibrating delay loop (skipped)... "
 	       "%lu.%02lu BogoMIPS preset\n",
 	       loops_per_jiffy/(1000000/HZ),
-- 
1.7.7.6