Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 605 insertions, 0 deletions

diff --git a/arch/alpha/lib/ev6-memset.S b/arch/alpha/lib/ev6-memset.S
new file mode 100644
index 000000000..89d7809da
--- /dev/null
+++ b/arch/alpha/lib/ev6-memset.S
@@ -0,0 +1,605 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * arch/alpha/lib/ev6-memset.S
+ *
+ * This is an efficient (and relatively small) implementation of the C library
+ * "memset()" function for the 21264 implementation of Alpha.
+ *
+ * 21264 version  contributed by Rick Gorton <rick.gorton@alpha-processor.com>
+ *
+ * Much of the information about 21264 scheduling/coding comes from:
+ *	Compiler Writer's Guide for the Alpha 21264
+ *	abbreviated as 'CWG' in other comments here
+ *	ftp.digital.com/pub/Digital/info/semiconductor/literature/dsc-library.html
+ * Scheduling notation:
+ *	E	- either cluster
+ *	U	- upper subcluster; U0 - subcluster U0; U1 - subcluster U1
+ *	L	- lower subcluster; L0 - subcluster L0; L1 - subcluster L1
+ * The algorithm for the leading and trailing quadwords remains the same,
+ * however the loop has been unrolled to enable better memory throughput,
+ * and the code has been replicated for each of the entry points: __memset
+ * and __memset16 to permit better scheduling to eliminate the stalling
+ * encountered during the mask replication.
+ * A future enhancement might be to put in a byte store loop for really
+ * small (say < 32 bytes) memset()s.  Whether or not that change would be
+ * a win in the kernel would depend upon the contextual usage.
+ * WARNING: Maintaining this is going to be more work than the above version,
+ * as fixes will need to be made in multiple places.  The performance gain
+ * is worth it.
+ */
+#include <linux/export.h>
+	.set noat
+	.set noreorder
+.text
+	.globl memset
+	.globl __memset
+	.globl ___memset
+	.globl __memset16
+	.globl __constant_c_memset
+
+	.ent ___memset
+.align 5
+___memset:
+	.frame $30,0,$26,0
+	.prologue 0
+
+	/*
+	 * Serious stalling happens.  The only way to mitigate this is to
+	 * undertake a major re-write to interleave the constant materialization
+	 * with other parts of the fall-through code.  This is important, even
+	 * though it makes maintenance tougher.
+	 * Do this later.
+	 */
+	and $17,255,$1		# E : 00000000000000ch
+	insbl $17,1,$2		# U : 000000000000ch00
+	bis $16,$16,$0		# E : return value
+	ble $18,end_b		# U : zero length requested?
+
+	addq $18,$16,$6		# E : max address to write to
+	bis	$1,$2,$17	# E : 000000000000chch
+	insbl	$1,2,$3		# U : 0000000000ch0000
+	insbl	$1,3,$4		# U : 00000000ch000000
+
+	or	$3,$4,$3	# E : 00000000chch0000
+	inswl	$17,4,$5	# U : 0000chch00000000
+	xor	$16,$6,$1	# E : will complete write be within one quadword?
+	inswl	$17,6,$2	# U : chch000000000000
+
+	or	$17,$3,$17	# E : 00000000chchchch
+	or	$2,$5,$2	# E : chchchch00000000
+	bic	$1,7,$1		# E : fit within a single quadword?
+	and	$16,7,$3	# E : Target addr misalignment
+
+	or	$17,$2,$17	# E : chchchchchchchch
+	beq	$1,within_quad_b # U :
+	nop			# E :
+	beq	$3,aligned_b	# U : target is 0mod8
+
+	/*
+	 * Target address is misaligned, and won't fit within a quadword
+	 */
+	ldq_u $4,0($16)		# L : Fetch first partial
+	bis $16,$16,$5		# E : Save the address
+	insql $17,$16,$2	# U : Insert new bytes
+	subq $3,8,$3		# E : Invert (for addressing uses)
+
+	addq $18,$3,$18		# E : $18 is new count ($3 is negative)
+	mskql $4,$16,$4		# U : clear relevant parts of the quad
+	subq $16,$3,$16		# E : $16 is new aligned destination
+	bis $2,$4,$1		# E : Final bytes
+
+	nop
+	stq_u $1,0($5)		# L : Store result
+	nop
+	nop
+
+.align 4
+aligned_b:
+	/*
+	 * We are now guaranteed to be quad aligned, with at least
+	 * one partial quad to write.
+	 */
+
+	sra $18,3,$3		# U : Number of remaining quads to write
+	and $18,7,$18		# E : Number of trailing bytes to write
+	bis $16,$16,$5		# E : Save dest address
+	beq $3,no_quad_b	# U : tail stuff only
+
+	/*
+	 * it's worth the effort to unroll this and use wh64 if possible
+	 * Lifted a bunch of code from clear_user.S
+	 * At this point, entry values are:
+	 * $16	Current destination address
+	 * $5	A copy of $16
+	 * $6	The max quadword address to write to
+	 * $18	Number trailer bytes
+	 * $3	Number quads to write
+	 */
+
+	and	$16, 0x3f, $2	# E : Forward work (only useful for unrolled loop)
+	subq	$3, 16, $4	# E : Only try to unroll if > 128 bytes
+	subq	$2, 0x40, $1	# E : bias counter (aligning stuff 0mod64)
+	blt	$4, loop_b	# U :
+
+	/*
+	 * We know we've got at least 16 quads, minimum of one trip
+	 * through unrolled loop.  Do a quad at a time to get us 0mod64
+	 * aligned.
+	 */
+
+	nop			# E :
+	nop			# E :
+	nop			# E :
+	beq	$1, $bigalign_b	# U :
+
+$alignmod64_b:
+	stq	$17, 0($5)	# L :
+	subq	$3, 1, $3	# E : For consistency later
+	addq	$1, 8, $1	# E : Increment towards zero for alignment
+	addq	$5, 8, $4	# E : Initial wh64 address (filler instruction)
+
+	nop
+	nop
+	addq	$5, 8, $5	# E : Inc address
+	blt	$1, $alignmod64_b # U :
+
+$bigalign_b:
+	/*
+	 * $3 - number quads left to go
+	 * $5 - target address (aligned 0mod64)
+	 * $17 - mask of stuff to store
+	 * Scratch registers available: $7, $2, $4, $1
+	 * we know that we'll be taking a minimum of one trip through
+ 	 * CWG Section 3.7.6: do not expect a sustained store rate of > 1/cycle
+	 * Assumes the wh64 needs to be for 2 trips through the loop in the future
+	 * The wh64 is issued on for the starting destination address for trip +2
+	 * through the loop, and if there are less than two trips left, the target
+	 * address will be for the current trip.
+	 */
+
+$do_wh64_b:
+	wh64	($4)		# L1 : memory subsystem write hint
+	subq	$3, 24, $2	# E : For determining future wh64 addresses
+	stq	$17, 0($5)	# L :
+	nop			# E :
+
+	addq	$5, 128, $4	# E : speculative target of next wh64
+	stq	$17, 8($5)	# L :
+	stq	$17, 16($5)	# L :
+	addq	$5, 64, $7	# E : Fallback address for wh64 (== next trip addr)
+
+	stq	$17, 24($5)	# L :
+	stq	$17, 32($5)	# L :
+	cmovlt	$2, $7, $4	# E : Latency 2, extra mapping cycle
+	nop
+
+	stq	$17, 40($5)	# L :
+	stq	$17, 48($5)	# L :
+	subq	$3, 16, $2	# E : Repeat the loop at least once more?
+	nop
+
+	stq	$17, 56($5)	# L :
+	addq	$5, 64, $5	# E :
+	subq	$3, 8, $3	# E :
+	bge	$2, $do_wh64_b	# U :
+
+	nop
+	nop
+	nop
+	beq	$3, no_quad_b	# U : Might have finished already
+
+.align 4
+	/*
+	 * Simple loop for trailing quadwords, or for small amounts
+	 * of data (where we can't use an unrolled loop and wh64)
+	 */
+loop_b:
+	stq $17,0($5)		# L :
+	subq $3,1,$3		# E : Decrement number quads left
+	addq $5,8,$5		# E : Inc address
+	bne $3,loop_b		# U : more?
+
+no_quad_b:
+	/*
+	 * Write 0..7 trailing bytes.
+	 */
+	nop			# E :
+	beq $18,end_b		# U : All done?
+	ldq $7,0($5)		# L :
+	mskqh $7,$6,$2		# U : Mask final quad
+
+	insqh $17,$6,$4		# U : New bits
+	bis $2,$4,$1		# E : Put it all together
+	stq $1,0($5)		# L : And back to memory
+	ret $31,($26),1		# L0 :
+
+within_quad_b:
+	ldq_u $1,0($16)		# L :
+	insql $17,$16,$2	# U : New bits
+	mskql $1,$16,$4		# U : Clear old
+	bis $2,$4,$2		# E : New result
+
+	mskql $2,$6,$4		# U :
+	mskqh $1,$6,$2		# U :
+	bis $2,$4,$1		# E :
+	stq_u $1,0($16)		# L :
+
+end_b:
+	nop
+	nop
+	nop
+	ret $31,($26),1		# L0 :
+	.end ___memset
+	EXPORT_SYMBOL(___memset)
+
+	/*
+	 * This is the original body of code, prior to replication and
+	 * rescheduling.  Leave it here, as there may be calls to this
+	 * entry point.
+	 */
+.align 4
+	.ent __constant_c_memset
+__constant_c_memset:
+	.frame $30,0,$26,0
+	.prologue 0
+
+	addq $18,$16,$6		# E : max address to write to
+	bis $16,$16,$0		# E : return value
+	xor $16,$6,$1		# E : will complete write be within one quadword?
+	ble $18,end		# U : zero length requested?
+
+	bic $1,7,$1		# E : fit within a single quadword
+	beq $1,within_one_quad	# U :
+	and $16,7,$3		# E : Target addr misalignment
+	beq $3,aligned		# U : target is 0mod8
+
+	/*
+	 * Target address is misaligned, and won't fit within a quadword
+	 */
+	ldq_u $4,0($16)		# L : Fetch first partial
+	bis $16,$16,$5		# E : Save the address
+	insql $17,$16,$2	# U : Insert new bytes
+	subq $3,8,$3		# E : Invert (for addressing uses)
+
+	addq $18,$3,$18		# E : $18 is new count ($3 is negative)
+	mskql $4,$16,$4		# U : clear relevant parts of the quad
+	subq $16,$3,$16		# E : $16 is new aligned destination
+	bis $2,$4,$1		# E : Final bytes
+
+	nop
+	stq_u $1,0($5)		# L : Store result
+	nop
+	nop
+
+.align 4
+aligned:
+	/*
+	 * We are now guaranteed to be quad aligned, with at least
+	 * one partial quad to write.
+	 */
+
+	sra $18,3,$3		# U : Number of remaining quads to write
+	and $18,7,$18		# E : Number of trailing bytes to write
+	bis $16,$16,$5		# E : Save dest address
+	beq $3,no_quad		# U : tail stuff only
+
+	/*
+	 * it's worth the effort to unroll this and use wh64 if possible
+	 * Lifted a bunch of code from clear_user.S
+	 * At this point, entry values are:
+	 * $16	Current destination address
+	 * $5	A copy of $16
+	 * $6	The max quadword address to write to
+	 * $18	Number trailer bytes
+	 * $3	Number quads to write
+	 */
+
+	and	$16, 0x3f, $2	# E : Forward work (only useful for unrolled loop)
+	subq	$3, 16, $4	# E : Only try to unroll if > 128 bytes
+	subq	$2, 0x40, $1	# E : bias counter (aligning stuff 0mod64)
+	blt	$4, loop	# U :
+
+	/*
+	 * We know we've got at least 16 quads, minimum of one trip
+	 * through unrolled loop.  Do a quad at a time to get us 0mod64
+	 * aligned.
+	 */
+
+	nop			# E :
+	nop			# E :
+	nop			# E :
+	beq	$1, $bigalign	# U :
+
+$alignmod64:
+	stq	$17, 0($5)	# L :
+	subq	$3, 1, $3	# E : For consistency later
+	addq	$1, 8, $1	# E : Increment towards zero for alignment
+	addq	$5, 8, $4	# E : Initial wh64 address (filler instruction)
+
+	nop
+	nop
+	addq	$5, 8, $5	# E : Inc address
+	blt	$1, $alignmod64	# U :
+
+$bigalign:
+	/*
+	 * $3 - number quads left to go
+	 * $5 - target address (aligned 0mod64)
+	 * $17 - mask of stuff to store
+	 * Scratch registers available: $7, $2, $4, $1
+	 * we know that we'll be taking a minimum of one trip through
+ 	 * CWG Section 3.7.6: do not expect a sustained store rate of > 1/cycle
+	 * Assumes the wh64 needs to be for 2 trips through the loop in the future
+	 * The wh64 is issued on for the starting destination address for trip +2
+	 * through the loop, and if there are less than two trips left, the target
+	 * address will be for the current trip.
+	 */
+
+$do_wh64:
+	wh64	($4)		# L1 : memory subsystem write hint
+	subq	$3, 24, $2	# E : For determining future wh64 addresses
+	stq	$17, 0($5)	# L :
+	nop			# E :
+
+	addq	$5, 128, $4	# E : speculative target of next wh64
+	stq	$17, 8($5)	# L :
+	stq	$17, 16($5)	# L :
+	addq	$5, 64, $7	# E : Fallback address for wh64 (== next trip addr)
+
+	stq	$17, 24($5)	# L :
+	stq	$17, 32($5)	# L :
+	cmovlt	$2, $7, $4	# E : Latency 2, extra mapping cycle
+	nop
+
+	stq	$17, 40($5)	# L :
+	stq	$17, 48($5)	# L :
+	subq	$3, 16, $2	# E : Repeat the loop at least once more?
+	nop
+
+	stq	$17, 56($5)	# L :
+	addq	$5, 64, $5	# E :
+	subq	$3, 8, $3	# E :
+	bge	$2, $do_wh64	# U :
+
+	nop
+	nop
+	nop
+	beq	$3, no_quad	# U : Might have finished already
+
+.align 4
+	/*
+	 * Simple loop for trailing quadwords, or for small amounts
+	 * of data (where we can't use an unrolled loop and wh64)
+	 */
+loop:
+	stq $17,0($5)		# L :
+	subq $3,1,$3		# E : Decrement number quads left
+	addq $5,8,$5		# E : Inc address
+	bne $3,loop		# U : more?
+
+no_quad:
+	/*
+	 * Write 0..7 trailing bytes.
+	 */
+	nop			# E :
+	beq $18,end		# U : All done?
+	ldq $7,0($5)		# L :
+	mskqh $7,$6,$2		# U : Mask final quad
+
+	insqh $17,$6,$4		# U : New bits
+	bis $2,$4,$1		# E : Put it all together
+	stq $1,0($5)		# L : And back to memory
+	ret $31,($26),1		# L0 :
+
+within_one_quad:
+	ldq_u $1,0($16)		# L :
+	insql $17,$16,$2	# U : New bits
+	mskql $1,$16,$4		# U : Clear old
+	bis $2,$4,$2		# E : New result
+
+	mskql $2,$6,$4		# U :
+	mskqh $1,$6,$2		# U :
+	bis $2,$4,$1		# E :
+	stq_u $1,0($16)		# L :
+
+end:
+	nop
+	nop
+	nop
+	ret $31,($26),1		# L0 :
+	.end __constant_c_memset
+	EXPORT_SYMBOL(__constant_c_memset)
+
+	/*
+	 * This is a replicant of the __constant_c_memset code, rescheduled
+	 * to mask stalls.  Note that entry point names also had to change
+	 */
+	.align 5
+	.ent __memset16
+
+__memset16:
+	.frame $30,0,$26,0
+	.prologue 0
+
+	inswl $17,0,$5		# U : 000000000000c1c2
+	inswl $17,2,$2		# U : 00000000c1c20000
+	bis $16,$16,$0		# E : return value
+	addq	$18,$16,$6	# E : max address to write to
+
+	ble $18, end_w		# U : zero length requested?
+	inswl	$17,4,$3	# U : 0000c1c200000000
+	inswl	$17,6,$4	# U : c1c2000000000000
+	xor	$16,$6,$1	# E : will complete write be within one quadword?
+
+	or	$2,$5,$2	# E : 00000000c1c2c1c2
+	or	$3,$4,$17	# E : c1c2c1c200000000
+	bic	$1,7,$1		# E : fit within a single quadword
+	and	$16,7,$3	# E : Target addr misalignment
+
+	or	$17,$2,$17	# E : c1c2c1c2c1c2c1c2
+	beq $1,within_quad_w	# U :
+	nop
+	beq $3,aligned_w	# U : target is 0mod8
+
+	/*
+	 * Target address is misaligned, and won't fit within a quadword
+	 */
+	ldq_u $4,0($16)		# L : Fetch first partial
+	bis $16,$16,$5		# E : Save the address
+	insql $17,$16,$2	# U : Insert new bytes
+	subq $3,8,$3		# E : Invert (for addressing uses)
+
+	addq $18,$3,$18		# E : $18 is new count ($3 is negative)
+	mskql $4,$16,$4		# U : clear relevant parts of the quad
+	subq $16,$3,$16		# E : $16 is new aligned destination
+	bis $2,$4,$1		# E : Final bytes
+
+	nop
+	stq_u $1,0($5)		# L : Store result
+	nop
+	nop
+
+.align 4
+aligned_w:
+	/*
+	 * We are now guaranteed to be quad aligned, with at least
+	 * one partial quad to write.
+	 */
+
+	sra $18,3,$3		# U : Number of remaining quads to write
+	and $18,7,$18		# E : Number of trailing bytes to write
+	bis $16,$16,$5		# E : Save dest address
+	beq $3,no_quad_w	# U : tail stuff only
+
+	/*
+	 * it's worth the effort to unroll this and use wh64 if possible
+	 * Lifted a bunch of code from clear_user.S
+	 * At this point, entry values are:
+	 * $16	Current destination address
+	 * $5	A copy of $16
+	 * $6	The max quadword address to write to
+	 * $18	Number trailer bytes
+	 * $3	Number quads to write
+	 */
+
+	and	$16, 0x3f, $2	# E : Forward work (only useful for unrolled loop)
+	subq	$3, 16, $4	# E : Only try to unroll if > 128 bytes
+	subq	$2, 0x40, $1	# E : bias counter (aligning stuff 0mod64)
+	blt	$4, loop_w	# U :
+
+	/*
+	 * We know we've got at least 16 quads, minimum of one trip
+	 * through unrolled loop.  Do a quad at a time to get us 0mod64
+	 * aligned.
+	 */
+
+	nop			# E :
+	nop			# E :
+	nop			# E :
+	beq	$1, $bigalign_w	# U :
+
+$alignmod64_w:
+	stq	$17, 0($5)	# L :
+	subq	$3, 1, $3	# E : For consistency later
+	addq	$1, 8, $1	# E : Increment towards zero for alignment
+	addq	$5, 8, $4	# E : Initial wh64 address (filler instruction)
+
+	nop
+	nop
+	addq	$5, 8, $5	# E : Inc address
+	blt	$1, $alignmod64_w	# U :
+
+$bigalign_w:
+	/*
+	 * $3 - number quads left to go
+	 * $5 - target address (aligned 0mod64)
+	 * $17 - mask of stuff to store
+	 * Scratch registers available: $7, $2, $4, $1
+	 * we know that we'll be taking a minimum of one trip through
+ 	 * CWG Section 3.7.6: do not expect a sustained store rate of > 1/cycle
+	 * Assumes the wh64 needs to be for 2 trips through the loop in the future
+	 * The wh64 is issued on for the starting destination address for trip +2
+	 * through the loop, and if there are less than two trips left, the target
+	 * address will be for the current trip.
+	 */
+
+$do_wh64_w:
+	wh64	($4)		# L1 : memory subsystem write hint
+	subq	$3, 24, $2	# E : For determining future wh64 addresses
+	stq	$17, 0($5)	# L :
+	nop			# E :
+
+	addq	$5, 128, $4	# E : speculative target of next wh64
+	stq	$17, 8($5)	# L :
+	stq	$17, 16($5)	# L :
+	addq	$5, 64, $7	# E : Fallback address for wh64 (== next trip addr)
+
+	stq	$17, 24($5)	# L :
+	stq	$17, 32($5)	# L :
+	cmovlt	$2, $7, $4	# E : Latency 2, extra mapping cycle
+	nop
+
+	stq	$17, 40($5)	# L :
+	stq	$17, 48($5)	# L :
+	subq	$3, 16, $2	# E : Repeat the loop at least once more?
+	nop
+
+	stq	$17, 56($5)	# L :
+	addq	$5, 64, $5	# E :
+	subq	$3, 8, $3	# E :
+	bge	$2, $do_wh64_w	# U :
+
+	nop
+	nop
+	nop
+	beq	$3, no_quad_w	# U : Might have finished already
+
+.align 4
+	/*
+	 * Simple loop for trailing quadwords, or for small amounts
+	 * of data (where we can't use an unrolled loop and wh64)
+	 */
+loop_w:
+	stq $17,0($5)		# L :
+	subq $3,1,$3		# E : Decrement number quads left
+	addq $5,8,$5		# E : Inc address
+	bne $3,loop_w		# U : more?
+
+no_quad_w:
+	/*
+	 * Write 0..7 trailing bytes.
+	 */
+	nop			# E :
+	beq $18,end_w		# U : All done?
+	ldq $7,0($5)		# L :
+	mskqh $7,$6,$2		# U : Mask final quad
+
+	insqh $17,$6,$4		# U : New bits
+	bis $2,$4,$1		# E : Put it all together
+	stq $1,0($5)		# L : And back to memory
+	ret $31,($26),1		# L0 :
+
+within_quad_w:
+	ldq_u $1,0($16)		# L :
+	insql $17,$16,$2	# U : New bits
+	mskql $1,$16,$4		# U : Clear old
+	bis $2,$4,$2		# E : New result
+
+	mskql $2,$6,$4		# U :
+	mskqh $1,$6,$2		# U :
+	bis $2,$4,$1		# E :
+	stq_u $1,0($16)		# L :
+
+end_w:
+	nop
+	nop
+	nop
+	ret $31,($26),1		# L0 :
+
+	.end __memset16
+	EXPORT_SYMBOL(__memset16)
+
+memset = ___memset
+__memset = ___memset
+	EXPORT_SYMBOL(memset)
+	EXPORT_SYMBOL(__memset)