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[PATCH 4.9 35/66] ARC: udelay: fix inline assembler by adding LP_COUNT to clobber list

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4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Vineet Gupta <vgupta@synopsys.com>

commit 36425cd67052e3becf325fd4d3ba5691791ef7e4 upstream.

commit 3c7c7a2fc8811bc ("ARC: Don't use "+l" inline asm constraint")
modified the inline assembly to setup LP_COUNT register manually and NOT
rely on gcc to do it (with the +l inline assembler contraint hint, now
being retired in the compiler)

However the fix was flawed as we didn't add LP_COUNT to asm clobber list,
meaning gcc doesn't know that LP_COUNT or zero-delay-loops are in action
in the inline asm.

This resulted in some fun - as nested ZOL loops were being generared

| mov lp_count,250000 ;16 # tmp235,
| lp .L__GCC__LP14 #		<======= OUTER LOOP (gcc generated)
|   .L14:
|   ld r2, [r5] # MEM[(volatile u32 *)prephitmp_43], w
|   dmb 1
|   breq r2, -1, @.L21 #, w,,
|   bbit0 r2,1,@.L13 # w,,
|   ld r4,[r7] ;25 # loops_per_jiffy, loops_per_jiffy
|   mpymu r3,r4,r6 #, loops_per_jiffy, tmp234
|
|   mov lp_count, r3 #		 <====== INNER LOOP (from inline asm)
|   lp 1f
| 	 nop
|   1:
|   nop_s
| .L__GCC__LP14: ; loop end, start is @.L14 #,

This caused issues with drivers relying on sane behaviour of udelay
friends.

With LP_COUNT added to clobber list, gcc doesn't generate the outer
loop in say above case.

Addresses STAR 9001146134

Reported-by: Joao Pinto <jpinto@synopsys.com>
Fixes: 3c7c7a2fc8811bc ("ARC: Don't use "+l" inline asm constraint")
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/arc/include/asm/delay.h |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

--- a/arch/arc/include/asm/delay.h
+++ b/arch/arc/include/asm/delay.h
@@ -26,7 +26,9 @@ static inline void __delay(unsigned long
 	"	lp  1f			\n"
 	"	nop			\n"
 	"1:				\n"
-	: : "r"(loops));
+	:
+        : "r"(loops)
+        : "lp_count");
 }
 
 extern void __bad_udelay(void);

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[PATCH 4.9 00/66] 4.9.7-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-31 06:50 +0100
  [PATCH 4.9 53/66] IB/umem: Release pid in error and ODP flow Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-31 06:50 +0100
  [PATCH 4.9 40/66] NFSv4.0: always send mode in SETATTR after EXCLUSIVE4 Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-31 06:50 +0100
  [PATCH 4.9 43/66] [media] pctv452e: move buffer to heap, no mutex Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-31 06:50 +0100
  [PATCH 4.9 28/66] s390/ptrace: Preserve previous registers for short regset write Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-31 06:50 +0100
  [PATCH 4.9 22/66] ISDN: eicon: silence misleading array-bounds warning Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-31 06:50 +0100
  [PATCH 4.9 57/66] pinctrl: broxton: Use correct PADCFGLOCK offset Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-31 06:50 +0100
  [PATCH 4.9 41/66] SUNRPC: cleanup ida information when removing sunrpc module Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-31 06:50 +0100
  [PATCH 4.9 35/66] ARC: udelay: fix inline assembler by adding LP_COUNT to clobber list Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-31 06:50 +0100
  [PATCH 4.9 44/66] [media] v4l: tvp5150: Reset device at probe time, not in get/set format handlers Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-31 06:50 +0100
  [PATCH 4.9 38/66] nfs: Dont increment lock sequence ID after NFS4ERR_MOVED Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-31 06:50 +0100
  [PATCH 4.9 37/66] parisc: Dont use BITS_PER_LONG in userspace-exported swab.h header Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-31 06:50 +0100
  [PATCH 4.9 39/66] NFSv4.1: Fix a deadlock in layoutget Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-31 06:50 +0100
  [PATCH 4.9 32/66] IB/srp: fix invalid indirect_sg_entries parameter value Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-31 06:50 +0100
  [PATCH 4.9 54/66] IB/rxe: Fix rxe dev insertion to rxe_dev_list Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-31 06:50 +0100
  [PATCH 4.9 48/66] drm/i915: prevent crash with .disable_display parameter Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-31 06:50 +0100
  [PATCH 4.9 03/66] drm: Schedule the output_poll_work with 1s delay if we have delayed event Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-31 07:00 +0100
  [PATCH 4.9 56/66] [media] s5k4ecgx: select CRC32 helper Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-31 07:00 +0100
  [PATCH 4.9 29/66] IB/cxgb3: fix misspelling in header guard Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-31 07:00 +0100
  [PATCH 4.9 23/66] Btrfs: remove old tree_root case in btrfs_read_locked_inode() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-31 07:00 +0100
  [PATCH 4.9 64/66] mm, memcg: do not retry precharge charges Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-31 07:00 +0100
  [PATCH 4.9 12/66] mm/huge_memory.c: respect FOLL_FORCE/FOLL_COW for thp Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-31 07:00 +0100
  [PATCH 4.9 30/66] IB/iser: Fix sg_tablesize calculation Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-31 07:00 +0100
  [PATCH 4.9 15/66] mm, page_alloc: fix fast-path race with cpuset update or removal Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-31 07:00 +0100
  [PATCH 4.9 01/66] fbdev: color map copying bounds checking Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-31 07:00 +0100
  [PATCH 4.9 25/66] Btrfs: remove ->{get, set}_acl() from btrfs_dir_ro_inode_operations Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-31 07:00 +0100
  [PATCH 4.9 65/66] perf/core: Fix concurrent sys_perf_event_open() vs. move_group race Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-31 07:00 +0100
  [PATCH 4.9 13/66] mm/mempolicy.c: do not put mempolicy before using its nodemask Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-31 07:00 +0100
  [PATCH 4.9 46/66] [media] v4l: tvp5150: Dont override output pinmuxing at stream on/off time Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-31 07:00 +0100
  [PATCH 4.9 16/66] mm, page_alloc: move cpuset seqcount checking to slowpath Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-31 07:00 +0100
  [PATCH 4.9 24/66] Btrfs: disable xattr operations on subvolume directories Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-31 07:00 +0100
  [PATCH 4.9 55/66] IB/rxe: Prevent from completer to operate on non valid QP Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-31 07:00 +0100
  [PATCH 4.9 62/66] platform/x86: mlx-platform: free first dev on error Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-31 07:00 +0100
  [PATCH 4.9 63/66] platform/x86: intel_mid_powerbtn: Set IRQ_ONESHOT Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-31 07:00 +0100
  [PATCH 4.9 11/66] drm/atomic: clear out fence when duplicating state Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-31 07:00 +0100
  [PATCH 4.9 61/66] virtio_mmio: Set DMA masks appropriately Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-31 07:00 +0100
  [PATCH 4.9 07/66] drm/vc4: Fix an integer overflow in temporary allocation layout. Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-31 07:00 +0100
  [PATCH 4.9 59/66] pinctrl: baytrail: Rectify debounce support Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-31 07:00 +0100
  [PATCH 4.9 06/66] drm/vc4: Fix memory leak of the CRTC state. Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-31 07:00 +0100
  [PATCH 4.9 10/66] Revert "drm/radeon: always apply pci shutdown callbacks" Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-31 07:00 +0100
  [PATCH 4.9 14/66] mm, page_alloc: fix check for NULL preferred_zone Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-31 07:00 +0100
  [PATCH 4.9 17/66] mm, page_alloc: fix premature OOM when racing with cpuset mems update Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-31 07:00 +0100
  [PATCH 4.9 60/66] memory_hotplug: make zone_can_shift() return a boolean value Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-31 07:00 +0100
  Re: [PATCH 4.9 00/66] 4.9.7-stable review Guenter Roeck <linux@roeck-us.net> - 2017-01-31 19:30 +0100
    Re: [PATCH 4.9 00/66] 4.9.7-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-31 21:20 +0100
  Re: [PATCH 4.9 00/66] 4.9.7-stable review Shuah Khan <shuahkh@osg.samsung.com> - 2017-01-31 23:20 +0100
    Re: [PATCH 4.9 00/66] 4.9.7-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-02-01 08:30 +0100

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