From: gdavis@mvista.com (gdavis at mvista.com)
To: linux-arm-kernel@lists.infradead.org
Subject: [RFC/PATCH v5 6/7] ARM: ARM11 MPCore: Make DMA_CACHE_RWFO operations preempt safe
Date: Tue, 12 Jun 2012 16:40:17 -0400 [thread overview]
Message-ID: <1339533618-15969-7-git-send-email-gdavis@mvista.com> (raw)
In-Reply-To: <1339533618-15969-1-git-send-email-gdavis@mvista.com>
From: George G. Davis <gdavis@mvista.com>
The DMA_CACHE_RWFO operations are not preempt safe. If preemption
occurs immediately following a RWFO operation on a cache line of
CPU A, it is possible for task migration to occur on resume at
which point the subsequent cache maintenance operation on the
same cache line of CPU B will have no affect on the CPU A cache
line leading to inconsistent memory and/or cache state. To prevent
this, disable preemption during RWFO operations.
This change depends on "ARM: Move get_thread_info macro definition
to <asm/assembler.h>".
Signed-off-by: George G. Davis <gdavis@mvista.com>
---
arch/arm/mm/cache-v6.S | 45 +++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 45 insertions(+), 0 deletions(-)
diff --git a/arch/arm/mm/cache-v6.S b/arch/arm/mm/cache-v6.S
index 4b10760..ee36b6c 100644
--- a/arch/arm/mm/cache-v6.S
+++ b/arch/arm/mm/cache-v6.S
@@ -203,6 +203,12 @@ ENTRY(v6_flush_kern_dcache_area)
*/
v6_dma_inv_range:
#ifdef CONFIG_DMA_CACHE_RWFO
+#ifdef CONFIG_PREEMPT
+ get_thread_info ip
+ ldr r3, [ip, #TI_PREEMPT] @ get preempt count
+ add r2, r3, #1 @ increment it
+ str r2, [ip, #TI_PREEMPT] @ disable preempt
+#endif
ldrb r2, [r0] @ read for ownership
strb r2, [r0] @ write for ownership
#endif
@@ -239,6 +245,15 @@ v6_dma_inv_range:
blo 1b
mov r0, #0
mcr p15, 0, r0, c7, c10, 4 @ drain write buffer
+#if defined(CONFIG_DMA_CACHE_RWFO) && defined(CONFIG_PREEMPT)
+ teq r3, #0 @ preempt count == 0?
+ str r3, [ip, #TI_PREEMPT] @ restore preempt count
+ bne 99f @ done if non-zero
+ ldr r3, [ip, #TI_FLAGS] @ else check flags
+ tst r3, #_TIF_NEED_RESCHED @ need resched?
+ bne preempt_schedule @ yes, do preempt_schedule
+99:
+#endif
mov pc, lr
/*
@@ -247,6 +262,12 @@ v6_dma_inv_range:
* - end - virtual end address of region
*/
v6_dma_clean_range:
+#if defined(CONFIG_DMA_CACHE_RWFO) && defined(CONFIG_PREEMPT)
+ get_thread_info ip
+ ldr r3, [ip, #TI_PREEMPT] @ get preempt count
+ add r2, r3, #1 @ increment it
+ str r2, [ip, #TI_PREEMPT] @ disable preempt
+#endif
bic r0, r0, #D_CACHE_LINE_SIZE - 1
1:
#ifdef CONFIG_DMA_CACHE_RWFO
@@ -262,6 +283,15 @@ v6_dma_clean_range:
blo 1b
mov r0, #0
mcr p15, 0, r0, c7, c10, 4 @ drain write buffer
+#if defined(CONFIG_DMA_CACHE_RWFO) && defined(CONFIG_PREEMPT)
+ teq r3, #0 @ preempt count == 0?
+ str r3, [ip, #TI_PREEMPT] @ restore preempt count
+ bne 99f @ done if non-zero
+ ldr r3, [ip, #TI_FLAGS] @ else check flags
+ tst r3, #_TIF_NEED_RESCHED @ need resched?
+ bne preempt_schedule @ yes, do preempt_schedule
+99:
+#endif
mov pc, lr
/*
@@ -271,6 +301,12 @@ v6_dma_clean_range:
*/
ENTRY(v6_dma_flush_range)
#ifdef CONFIG_DMA_CACHE_RWFO
+#ifdef CONFIG_PREEMPT
+ get_thread_info ip
+ ldr r3, [ip, #TI_PREEMPT] @ get preempt count
+ add r2, r3, #1 @ increment it
+ str r2, [ip, #TI_PREEMPT] @ disable preempt
+#endif
ldrb r2, [r0] @ read for ownership
strb r2, [r0] @ write for ownership
#endif
@@ -290,6 +326,15 @@ ENTRY(v6_dma_flush_range)
blo 1b
mov r0, #0
mcr p15, 0, r0, c7, c10, 4 @ drain write buffer
+#if defined(CONFIG_DMA_CACHE_RWFO) && defined(CONFIG_PREEMPT)
+ teq r3, #0 @ preempt count == 0?
+ str r3, [ip, #TI_PREEMPT] @ restore preempt count
+ bne 99f @ done if non-zero
+ ldr r3, [ip, #TI_FLAGS] @ else check flags
+ tst r3, #_TIF_NEED_RESCHED @ need resched?
+ bne preempt_schedule @ yes, do preempt_schedule
+99:
+#endif
mov pc, lr
/*
--
1.7.4.4
next prev parent reply other threads:[~2012-06-12 20:40 UTC|newest]
Thread overview: 93+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-06-20 13:43 parallel load of modules on an ARM multicore EXTERNAL Waechtler Peter (Fa. TCP, CM-AI/PJ-CF31)
2011-06-21 15:50 ` Catalin Marinas
2011-06-23 14:39 ` AW: " EXTERNAL Waechtler Peter (Fa. TCP, CM-AI/PJ-CF31)
2011-06-23 14:52 ` Catalin Marinas
2011-06-23 15:12 ` Russell King - ARM Linux
2011-06-23 15:34 ` Catalin Marinas
2011-06-23 17:02 ` Catalin Marinas
2011-06-23 15:20 ` AW: " EXTERNAL Waechtler Peter (Fa. TCP, CM-AI/PJ-CF31)
2011-07-07 4:25 ` George G. Davis
2011-10-20 4:04 ` George G. Davis
2011-09-22 7:29 ` George G. Davis
2011-09-22 8:52 ` Catalin Marinas
2011-10-06 4:29 ` George G. Davis
2011-10-06 5:08 ` [RFC/PATCH 0/7] ARM: ARM11 MPCore preemption/task migration cache coherency fixups gdavis at mvista.com
2011-10-06 5:08 ` [RFC/PATCH 1/7] ARM: ARM11 MPCore: pgd_alloc is not preempt safe gdavis at mvista.com
2011-10-06 16:35 ` Russell King - ARM Linux
2011-10-06 19:38 ` George G. Davis
2011-10-06 5:08 ` [RFC/PATCH 2/7] ARM: ARM11 MPCore: pte_alloc_one{, _kernel} are " gdavis at mvista.com
2011-10-06 5:08 ` [RFC/PATCH 3/7] ARM: ARM11 MPCore: {clean, flush}_pmd_entry " gdavis at mvista.com
2011-10-06 5:08 ` [RFC/PATCH 4/7] ARM: ARM11 MPCore: clean_dcache_area is " gdavis at mvista.com
2011-10-06 5:08 ` [RFC/PATCH 5/7] ARM: Move get_thread_info macro definition to <asm/assembler.h> gdavis at mvista.com
2011-10-06 5:08 ` [RFC/PATCH 6/7] ARM: ARM11 MPCore: DMA_CACHE_RWFO operations are not preempt safe gdavis at mvista.com
2011-10-06 16:40 ` Russell King - ARM Linux
2011-10-06 19:41 ` George G. Davis
2011-10-06 5:08 ` [RFC/PATCH 7/7] ARM: ARM11 MPCore: cpu_v6_set_pte_ext is " gdavis at mvista.com
2011-10-06 7:46 ` Russell King - ARM Linux
2011-10-06 12:35 ` George G. Davis
2011-10-07 2:38 ` [RFC/PATCH v2 0/7] ARM11 MPCore: preemption/task migration cache coherency fixups gdavis at mvista.com
2011-10-07 2:38 ` [RFC/PATCH 1/7] ARM: ARM11 MPCore: pgd_alloc is not preempt safe gdavis at mvista.com
2011-10-07 2:38 ` [RFC/PATCH 2/7] ARM: ARM11 MPCore: pte_alloc_one{, _kernel} are " gdavis at mvista.com
2011-10-07 7:47 ` [RFC/PATCH 2/7] ARM: ARM11 MPCore: pte_alloc_one{,_kernel} " Russell King - ARM Linux
2011-10-07 15:31 ` [RFC/PATCH 2/7] ARM: ARM11 MPCore: pte_alloc_one{, _kernel} " George G. Davis
2011-10-07 2:38 ` [RFC/PATCH 3/7] ARM: ARM11 MPCore: {clean, flush}_pmd_entry " gdavis at mvista.com
2011-10-11 9:53 ` [RFC/PATCH 3/7] ARM: ARM11 MPCore: {clean,flush}_pmd_entry " Catalin Marinas
2011-10-12 2:34 ` [RFC/PATCH 3/7] ARM: ARM11 MPCore: {clean, flush}_pmd_entry " George G. Davis
2011-10-13 14:31 ` [RFC/PATCH 3/7] ARM: ARM11 MPCore: {clean,flush}_pmd_entry " Russell King - ARM Linux
2011-10-14 1:34 ` [RFC/PATCH 3/7] ARM: ARM11 MPCore: {clean, flush}_pmd_entry " George G. Davis
2011-10-07 2:38 ` [RFC/PATCH 4/7] ARM: ARM11 MPCore: clean_dcache_area is " gdavis at mvista.com
2011-10-07 2:38 ` [RFC/PATCH 5/7] ARM: Move get_thread_info macro definition to <asm/assembler.h> gdavis at mvista.com
2011-10-11 9:56 ` Catalin Marinas
2011-10-12 6:04 ` gdavis at mvista.com
2011-10-13 14:34 ` Russell King - ARM Linux
2011-10-13 14:49 ` Catalin Marinas
2011-10-13 14:53 ` Russell King - ARM Linux
2011-10-14 1:46 ` George G. Davis
2011-10-14 1:44 ` George G. Davis
2011-10-14 1:42 ` George G. Davis
2011-10-14 2:54 ` Nicolas Pitre
2011-10-14 12:56 ` George G. Davis
2011-10-07 2:38 ` [RFC/PATCH 6/7] ARM: ARM11 MPCore: DMA_CACHE_RWFO operations are not preempt safe gdavis at mvista.com
2011-10-07 2:38 ` [RFC/PATCH 7/7] ARM: ARM11 MPCore: cpu_v6_set_pte_ext is " gdavis at mvista.com
2011-10-07 16:26 ` [RFC/PATCH v3 0/7] ARM11 MPCore: preemption/task migration cache coherency fixups gdavis at mvista.com
2011-10-07 16:26 ` [RFC/PATCH v3 1/7] ARM: ARM11 MPCore: pgd_alloc is not preempt safe gdavis at mvista.com
2011-10-07 16:26 ` [RFC/PATCH v3 2/7] ARM: ARM11 MPCore: pte_alloc_one{, _kernel} are " gdavis at mvista.com
2011-10-07 16:26 ` [RFC/PATCH v3 3/7] ARM: ARM11 MPCore: {clean, flush}_pmd_entry " gdavis at mvista.com
2011-10-07 16:26 ` [RFC/PATCH v3 4/7] ARM: ARM11 MPCore: clean_dcache_area is " gdavis at mvista.com
2011-10-07 16:26 ` [RFC/PATCH v3 5/7] ARM: Move get_thread_info macro definition to <asm/assembler.h> gdavis at mvista.com
2011-10-07 16:26 ` [RFC/PATCH v3 6/7] ARM: ARM11 MPCore: DMA_CACHE_RWFO operations are not preempt safe gdavis at mvista.com
2011-10-07 16:26 ` [RFC/PATCH v3 7/7] ARM: ARM11 MPCore: cpu_v6_set_pte_ext is " gdavis at mvista.com
2011-10-18 13:47 ` [RFC/PATCH v4 0/7] ARM11 MPCore: preemption/task migration cache coherency fixups gdavis at mvista.com
2011-10-18 13:47 ` [RFC/PATCH v4 1/7] ARM: ARM11 MPCore: pgd_alloc is not preempt safe gdavis at mvista.com
2011-10-18 13:47 ` [RFC/PATCH v4 2/7] ARM: ARM11 MPCore: pte_alloc_one{, _kernel} are " gdavis at mvista.com
2011-10-18 13:47 ` [RFC/PATCH v4 3/7] ARM: ARM11 MPCore: {clean, flush}_pmd_entry " gdavis at mvista.com
2011-10-18 13:47 ` [RFC/PATCH v4 4/7] ARM: ARM11 MPCore: clean_dcache_area is " gdavis at mvista.com
2011-10-18 17:08 ` Tony Lindgren
2011-10-18 17:30 ` George G. Davis
2011-10-18 17:43 ` Tony Lindgren
2011-10-18 18:13 ` George G. Davis
2011-10-18 13:47 ` [RFC/PATCH v4 5/7] ARM: Move get_thread_info macro definition to <asm/assembler.h> gdavis at mvista.com
2011-10-18 13:47 ` [RFC/PATCH v4 6/7] ARM: ARM11 MPCore: DMA_CACHE_RWFO operations are not preempt safe gdavis at mvista.com
2011-10-18 21:28 ` Nicolas Pitre
2011-10-18 23:26 ` George G. Davis
2011-10-19 1:09 ` Nicolas Pitre
2011-10-18 13:47 ` [RFC/PATCH v4 7/7] ARM: ARM11 MPCore: cpu_v6_set_pte_ext is " gdavis at mvista.com
2011-10-18 21:52 ` Nicolas Pitre
2011-10-18 23:29 ` George G. Davis
2012-06-12 20:40 ` [RFC/PATCH v5 0/7] ARM11 MPCore: preemption/task migration cache coherency fixups gdavis at mvista.com
2012-06-12 20:40 ` [RFC/PATCH v5 1/7] ARM: ARM11 MPCore: Make pgd_alloc preempt safe gdavis at mvista.com
2012-06-12 20:40 ` [RFC/PATCH v5 2/7] ARM: ARM11 MPCore: Make pte_alloc_one{, _kernel} " gdavis at mvista.com
2012-06-12 20:40 ` [RFC/PATCH v5 3/7] ARM: ARM11 MPCore: Make {clean, flush}_pmd_entry " gdavis at mvista.com
2012-06-12 20:40 ` [RFC/PATCH v5 4/7] ARM: Move get_thread_info macro definition to <asm/assembler.h> gdavis at mvista.com
2012-06-12 20:40 ` [RFC/PATCH v5 5/7] ARM: ARM11 MPCore: cpu_v6_dcache_clean_area needs RFO gdavis at mvista.com
2012-06-13 9:32 ` Catalin Marinas
2012-06-13 9:36 ` Russell King - ARM Linux
2012-06-13 9:41 ` Catalin Marinas
2012-06-13 9:45 ` Russell King - ARM Linux
2012-06-13 9:54 ` Catalin Marinas
2012-06-13 11:36 ` George G. Davis
2012-06-13 11:21 ` George G. Davis
2012-06-12 20:40 ` gdavis at mvista.com [this message]
2012-06-12 20:40 ` [RFC/PATCH v5 7/7] ARM: ARM11 MPCore: Make cpu_v6_set_pte_ext preempt safe gdavis at mvista.com
2012-06-13 9:34 ` Catalin Marinas
2012-06-13 11:35 ` George G. Davis
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