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Consolidate stack size information into THREAD_SIZE_ORDER

PATCH New Tim Bird 3 participants 4 messages May 24, 2012 – Jun 22, 2012 Arm (32-bit)

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Tim Bird

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#0 lore raw

PATCH 1/1 Consolidate stack size information into THREAD_SIZE_ORDER

This reduces the number of magic values in the code, as well as makes it easier to experiment with larger or smaller stack sizes.

Signed-off-by Tim Bird <[email protected]>

PATCH FOLLOWS

---
 arch/arm/include/asm/thread_info.h |    2 +-
 arch/arm/kernel/entry-header.S     |    8 ++++----
 arch/arm/mm/proc-macros.S          |    4 ++--
 3 files changed, 7 insertions(+), 7 deletions(-)
arch/arm/include/asm/thread_info.h +1 -1
index 0f04d84..5172c36 100644
@@ -16,7 +16,7 @@
 #include <asm/fpstate.h>
 
 #define THREAD_SIZE_ORDER	1
-#define THREAD_SIZE		8192
+#define THREAD_SIZE		(4096 << THREAD_SIZE_ORDER)
 #define THREAD_START_SP		(THREAD_SIZE - 8)
 
 #ifndef __ASSEMBLY__
arch/arm/kernel/entry-header.S +4 -4
index 9a8531e..f94216b 100644
@@ -109,8 +109,8 @@
 	.endm
 
 	.macro	get_thread_info, rd
-	mov	\rd, sp, lsr #13
-	mov	\rd, \rd, lsl #13
+	mov	\rd, sp, lsr #12 + THREAD_SIZE_ORDER
+	mov	\rd, \rd, lsl #12 + THREAD_SIZE_ORDER
 	.endm
 
 	@

@@ -150,8 +150,8 @@
 
 	.macro	get_thread_info, rd
 	mov	\rd, sp
-	lsr	\rd, \rd, #13
-	mov	\rd, \rd, lsl #13
+	lsr	\rd, \rd, #12 + THREAD_SIZE_ORDER
+	mov	\rd, \rd, lsl #12 + THREAD_SIZE_ORDER
 	.endm
 
 	@
arch/arm/mm/proc-macros.S +2 -2
index 2d8ff3a..7006c88 100644
@@ -30,8 +30,8 @@
  * act_mm - get current->active_mm
  */
 	.macro	act_mm, rd
-	bic	\rd, sp, #8128
-	bic	\rd, \rd, #63
+	mov	\rd, sp, lsr #12 + THREAD_SIZE_ORDER
+	mov	\rd, \rd, lsl #12 + THREAD_SIZE_ORDER
 	ldr	\rd, [\rd, #TI_TASK]
 	ldr	\rd, [\rd, #TSK_ACTIVE_MM]
 	.endm
Signature · 1 line
1.7.9.5
#1 lore raw

PATCH 1/1 Consolidate stack size information into THREAD_SIZE_ORDER

Quoted 4 lines · Tim Bird

This reduces the number of magic values in the code, as well as makes it easier to experiment with larger or smaller stack sizes.

Signed-off-by Tim Bird<[email protected]>

Just ran my eyes over it, looks fine.

Signature · 2 lines
Ben Dooks				http://www.codethink.co.uk/
Senior Engineer				Codethink - Providing Genius
author
#2 lore raw

PATCH 1/1 Consolidate stack size information into THREAD_SIZE_ORDER

In reply to Tim Bird

Any response to the following, which I submitted about a month ago? May I submit it to the ARM patch-queue? Note that Ben Dooks took a quick look at it, but I haven't gotten an official ACK-ed by from anyone.

It's rather trival, has no performance impact, and
makes the code more flexible IMHO. I realize it's
not the most important issue in the world, but it will make my life easier.

[original patch follows]

This reduces the number of magic values in the code, as well as makes it easier to experiment with larger or smaller stack sizes.

Signed-off-by Tim Bird <[email protected]>

PATCH FOLLOWS

---
 arch/arm/include/asm/thread_info.h |    2 +-
 arch/arm/kernel/entry-header.S     |    8 ++++----
 arch/arm/mm/proc-macros.S          |    4 ++--
 3 files changed, 7 insertions(+), 7 deletions(-)
arch/arm/include/asm/thread_info.h +1 -1
index 0f04d84..5172c36 100644
@@ -16,7 +16,7 @@
 #include <asm/fpstate.h>
 
 #define THREAD_SIZE_ORDER	1
-#define THREAD_SIZE		8192
+#define THREAD_SIZE		(4096 << THREAD_SIZE_ORDER)
 #define THREAD_START_SP		(THREAD_SIZE - 8)
 
 #ifndef __ASSEMBLY__
arch/arm/kernel/entry-header.S +4 -4
index 9a8531e..f94216b 100644
@@ -109,8 +109,8 @@
 	.endm
 
 	.macro	get_thread_info, rd
-	mov	\rd, sp, lsr #13
-	mov	\rd, \rd, lsl #13
+	mov	\rd, sp, lsr #12 + THREAD_SIZE_ORDER
+	mov	\rd, \rd, lsl #12 + THREAD_SIZE_ORDER
 	.endm
 
 	@

@@ -150,8 +150,8 @@
 
 	.macro	get_thread_info, rd
 	mov	\rd, sp
-	lsr	\rd, \rd, #13
-	mov	\rd, \rd, lsl #13
+	lsr	\rd, \rd, #12 + THREAD_SIZE_ORDER
+	mov	\rd, \rd, lsl #12 + THREAD_SIZE_ORDER
 	.endm
 
 	@
arch/arm/mm/proc-macros.S +2 -2
index 2d8ff3a..7006c88 100644
@@ -30,8 +30,8 @@
  * act_mm - get current->active_mm
  */
 	.macro	act_mm, rd
-	bic	\rd, sp, #8128
-	bic	\rd, \rd, #63
+	mov	\rd, sp, lsr #12 + THREAD_SIZE_ORDER
+	mov	\rd, \rd, lsl #12 + THREAD_SIZE_ORDER
 	ldr	\rd, [\rd, #TI_TASK]
 	ldr	\rd, [\rd, #TSK_ACTIVE_MM]
 	.endm
Signature · 1 line
1.7.9.5
#3 lore raw

PATCH 1/1 Consolidate stack size information into THREAD_SIZE_ORDER

Hi Tim,

Quoted 4 lines · Tim Bird

Any response to the following, which I submitted about a month ago? May I submit it to the ARM patch-queue? Note that Ben Dooks took a quick look at it, but I haven't gotten an official ACK-ed by from anyone.

[...]

Quoted 18 lines
arch/arm/include/asm/thread_info.h +1 -1
index 0f04d84..5172c36 100644
@@ -16,7 +16,7 @@
 #include <asm/fpstate.h>
 
 #define THREAD_SIZE_ORDER	1
-#define THREAD_SIZE		8192
+#define THREAD_SIZE		(4096 << THREAD_SIZE_ORDER)
 #define THREAD_START_SP		(THREAD_SIZE - 8)
 
 #ifndef __ASSEMBLY__
arch/arm/kernel/entry-header.S +0 -0
index 9a8531e..f94216b 100644

arch/arm/kernel/entry-header.S line 114

Quoted 8 lines
arch/arm/kernel/entry-header.S +2 -2
@@ -109,8 +109,8 @@
 	.endm
 
 	.macro	get_thread_info, rd
-	mov	\rd, sp, lsr #13
-	mov	\rd, \rd, lsl #13
+	mov	\rd, sp, lsr #12 + THREAD_SIZE_ORDER
+	mov	\rd, \rd, lsl #12 + THREAD_SIZE_ORDER
 	.endm

Maybe use PAGE_SHIFT instead of hardcoding the 12?

arch/arm/kernel/entry-header.S line 155

Quoted 10 lines
arch/arm/kernel/entry-header.S +2 -2
 	@

@@ -150,8 +150,8 @@
 
 	.macro	get_thread_info, rd
 	mov	\rd, sp
-	lsr	\rd, \rd, #13
-	mov	\rd, \rd, lsl #13
+	lsr	\rd, \rd, #12 + THREAD_SIZE_ORDER
+	mov	\rd, \rd, lsl #12 + THREAD_SIZE_ORDER
 	.endm

I appreciate you've followed the same style as before but while we're here maybe you could rewrite the lsr as a mov for consistency?

Will