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Message-Id: <20180118134808.40970-1-abrodkin@synopsys.com>
Date: Thu, 18 Jan 2018 16:48:08 +0300
From: Alexey Brodkin <Alexey.Brodkin@...opsys.com>
To: linux-snps-arc@...ts.infradead.org
Cc: linux-kernel@...r.kernel.org,
Vineet Gupta <Vineet.Gupta1@...opsys.com>,
Alexey Brodkin <Alexey.Brodkin@...opsys.com>
Subject: [PATCH] ARC: Allow disabling of prefetch operations for debugging purposes
Signed-off-by: Alexey Brodkin <abrodkin@...opsys.com>
---
arch/arc/Kconfig | 5 +++++
arch/arc/include/asm/processor.h | 11 +++++++++++
arch/arc/lib/memcpy-archs.S | 16 ++++++++++++++++
arch/arc/lib/memset-archs.S | 6 ++++++
4 files changed, 38 insertions(+)
diff --git a/arch/arc/Kconfig b/arch/arc/Kconfig
index 9d5fd00d9e91..aa5262e8e43f 100644
--- a/arch/arc/Kconfig
+++ b/arch/arc/Kconfig
@@ -532,6 +532,11 @@ config ARC_DBG_TLB_PARANOIA
bool "Paranoia Checks in Low Level TLB Handlers"
default n
+config ARC_DISABLE_PREFETCH
+ bool "Disable use of prefetch instructions"
+ default n
+ help
+ Suppresses usage of prefetchw and prealloc instructions.
endif
config ARC_UBOOT_SUPPORT
diff --git a/arch/arc/include/asm/processor.h b/arch/arc/include/asm/processor.h
index 8ee41e988169..01011c0515d4 100644
--- a/arch/arc/include/asm/processor.h
+++ b/arch/arc/include/asm/processor.h
@@ -106,6 +106,17 @@ extern unsigned int get_wchan(struct task_struct *p);
*/
#define current_text_addr() ({ __label__ _l; _l: &&_l; })
+#ifdef CONFIG_ARC_DISABLE_PREFETCH
+#define ARCH_HAS_PREFETCH
+#define prefetch(x)
+
+#define ARCH_HAS_PREFETCHW
+#define prefetchw(x)
+
+#define ARCH_HAS_SPINLOCK_PREFETCH
+#define spin_lock_prefetch(x)
+#endif /* CONFIG_ARC_DISABLE_PREFETCH */
+
#endif /* !__ASSEMBLY__ */
/*
diff --git a/arch/arc/lib/memcpy-archs.S b/arch/arc/lib/memcpy-archs.S
index d61044dd8b58..0a29d024be01 100644
--- a/arch/arc/lib/memcpy-archs.S
+++ b/arch/arc/lib/memcpy-archs.S
@@ -41,8 +41,10 @@
#endif
ENTRY_CFI(memcpy)
+#ifndef CONFIG_ARC_DISABLE_PREFETCH
prefetch [r1] ; Prefetch the read location
prefetchw [r0] ; Prefetch the write location
+#endif
mov.f 0, r2
;;; if size is zero
jz.d [blink]
@@ -72,8 +74,10 @@ ENTRY_CFI(memcpy)
lpnz @.Lcopy32_64bytes
;; LOOP START
LOADX (r6, r1)
+#ifndef CONFIG_ARC_DISABLE_PREFETCH
PREFETCH_READ (r1)
PREFETCH_WRITE (r3)
+#endif
LOADX (r8, r1)
LOADX (r10, r1)
LOADX (r4, r1)
@@ -117,9 +121,13 @@ ENTRY_CFI(memcpy)
lpnz @.Lcopy8bytes_1
;; LOOP START
ld.ab r6, [r1, 4]
+#ifndef CONFIG_ARC_DISABLE_PREFETCH
prefetch [r1, 28] ;Prefetch the next read location
+#endif
ld.ab r8, [r1,4]
+#ifndef CONFIG_ARC_DISABLE_PREFETCH
prefetchw [r3, 32] ;Prefetch the next write location
+#endif
SHIFT_1 (r7, r6, 24)
or r7, r7, r5
@@ -162,9 +170,13 @@ ENTRY_CFI(memcpy)
lpnz @.Lcopy8bytes_2
;; LOOP START
ld.ab r6, [r1, 4]
+#ifndef CONFIG_ARC_DISABLE_PREFETCH
prefetch [r1, 28] ;Prefetch the next read location
+#endif
ld.ab r8, [r1,4]
+#ifndef CONFIG_ARC_DISABLE_PREFETCH
prefetchw [r3, 32] ;Prefetch the next write location
+#endif
SHIFT_1 (r7, r6, 16)
or r7, r7, r5
@@ -204,9 +216,13 @@ ENTRY_CFI(memcpy)
lpnz @.Lcopy8bytes_3
;; LOOP START
ld.ab r6, [r1, 4]
+#ifndef CONFIG_ARC_DISABLE_PREFETCH
prefetch [r1, 28] ;Prefetch the next read location
+#endif
ld.ab r8, [r1,4]
+#ifndef CONFIG_ARC_DISABLE_PREFETCH
prefetchw [r3, 32] ;Prefetch the next write location
+#endif
SHIFT_1 (r7, r6, 8)
or r7, r7, r5
diff --git a/arch/arc/lib/memset-archs.S b/arch/arc/lib/memset-archs.S
index 62ad4bcb841a..343f292d92a0 100644
--- a/arch/arc/lib/memset-archs.S
+++ b/arch/arc/lib/memset-archs.S
@@ -11,7 +11,9 @@
#undef PREALLOC_NOT_AVAIL
ENTRY_CFI(memset)
+#ifndef CONFIG_ARC_DISABLE_PREFETCH
prefetchw [r0] ; Prefetch the write location
+#endif
mov.f 0, r2
;;; if size is zero
jz.d [blink]
@@ -48,11 +50,13 @@ ENTRY_CFI(memset)
lpnz @.Lset64bytes
;; LOOP START
+#ifndef CONFIG_ARC_DISABLE_PREFETCH
#ifdef PREALLOC_NOT_AVAIL
prefetchw [r3, 64] ;Prefetch the next write location
#else
prealloc [r3, 64]
#endif
+#endif /* CONFIG_ARC_DISABLE_PREFETCH */
#ifdef CONFIG_ARC_HAS_LL64
std.ab r4, [r3, 8]
std.ab r4, [r3, 8]
@@ -85,7 +89,9 @@ ENTRY_CFI(memset)
lsr.f lp_count, r2, 5 ;Last remaining max 124 bytes
lpnz .Lset32bytes
;; LOOP START
+#ifndef CONFIG_ARC_DISABLE_PREFETCH
prefetchw [r3, 32] ;Prefetch the next write location
+#endif
#ifdef CONFIG_ARC_HAS_LL64
std.ab r4, [r3, 8]
std.ab r4, [r3, 8]
--
2.11.0
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