Skip to contentSkip to conversation

ARM: V7M: Support caches

PATCH New Vladimir Murzin 3 participants 22 messages Jun 13, 2016 – Jun 15, 2016 Arm (32-bit)

lore
Share & tools
lore

Vladimir Murzin

author
#0 lore raw

cover ARM: V7M: Support caches

Hi,

This patch set allows M-class cpus benefit of optional cache support. It originaly was written by Jonny, I've been keeping it localy mainly rebasing over Linux versions.

The main idea behind patches is to reuse existing cache handling code from v7A/R. In case v7M cache operations are provided via memory mapped interface rather than co-processor instructions, so extra macros have been introduced to factor out cache handling logic and low-level operations.

Along with the v7M cache support the first user (Cortex-M7) is introduced.

Patches were tested on MPS2 platform with Cortex-M3/M4/M7. The later one showed significant boot speed-up.

Based on 4.7-rc3.

Thanks!
Vladimir

Jonathan Austin (9):
ARM: factor out CSSELR/CCSIDR operations that use cp15 directly
ARM: V7M: Make read_cpuid() generally available on V7M.
ARM: V7M: Add addresses for mem-mapped V7M cache operations
ARM: V7M: Add support for reading the CTR with CPUID_CACHETYPE
ARM: Extract cp15 operations from cache flush code
ARM: V7M: Implement cache macros for V7M
ARM: V7M: Wire up caches for V7M processors with cache support.
ARM: V7M: Indirect proc_info construction for V7M CPUs
ARM: V7M: Add support for the Cortex-M7 processor

Vladimir Murzin (1):
ARM: V7M: fix notrace variant of save_and_disable_irqs

 arch/arm/include/asm/assembler.h  |    4 ++
 arch/arm/include/asm/cachetype.h  |   39 ++++++++++
 arch/arm/include/asm/cputype.h    |   51 +++++++------
 arch/arm/include/asm/glue-cache.h |    4 --
 arch/arm/include/asm/v7m.h        |   22 ++++++
 arch/arm/kernel/head-nommu.S      |   16 ++++-
 arch/arm/kernel/setup.c           |   16 ++---
 arch/arm/mm/Kconfig               |    7 +-
 arch/arm/mm/Makefile              |    4 ++
 arch/arm/mm/cache-v7.S            |   73 +++++++++++--------
 arch/arm/mm/proc-macros.S         |   23 ------
 arch/arm/mm/proc-v7.S             |    1 +
 arch/arm/mm/proc-v7m.S            |   93 ++++++++++++++++++++----
 arch/arm/mm/v7-cache-macros.S     |  131 ++++++++++++++++++++++++++++++++++
 arch/arm/mm/v7m-cache-macros.S    |  142 +++++++++++++++++++++++++++++++++++++
 15 files changed, 520 insertions(+), 106 deletions(-)
 create mode 100644 arch/arm/mm/v7-cache-macros.S
 create mode 100644 arch/arm/mm/v7m-cache-macros.S
Signature · 1 line
1.7.9.5
author
#1 lore raw

PATCH 1/10 ARM: factor out CSSELR/CCSIDR operations that use cp15 directly

From: Jonathan Austin <[email protected]>

Currently we use raw cp15 operations to access the cache setup data.

This patch abstracts the CSSELR and CCSIDR accessors out to a header so that the implementation for them can be switched out as we do with other cpu/cachetype operations.

Signed-off-by Jonathan Austin <[email protected]>
Signed-off-by Vladimir Murzin <[email protected]>
---
 arch/arm/include/asm/cachetype.h |   24 ++++++++++++++++++++++++
 arch/arm/kernel/setup.c          |    7 ++-----
 2 files changed, 26 insertions(+), 5 deletions(-)
arch/arm/include/asm/cachetype.h +24 -0
index 7ea7814..8609de8 100644
@@ -56,4 +56,28 @@ static inline unsigned int __attribute__((pure)) cacheid_is(unsigned int mask)
 	       (~__CACHEID_NEVER & __CACHEID_ARCH_MIN & mask & cacheid);
 }
 
+#define CSSELR_ICACHE	1
+#define CSSELR_DCACHE	0
+
+#define CSSELR_L1	(0 << 1)
+#define CSSELR_L2	(1 << 1)
+#define CSSELR_L3	(2 << 1)
+#define CSSELR_L4	(3 << 1)
+#define CSSELR_L5	(4 << 1)
+#define CSSELR_L6	(5 << 1)
+#define CSSELR_L7	(6 << 1)
+
+static inline void set_csselr(unsigned int cache_selector)
+{
+	asm volatile("mcr p15, 2, %0, c0, c0, 0" : : "r" (cache_selector));
+}
+
+static inline unsigned int read_ccsidr(void)
+{
+	unsigned int val;
+
+	asm volatile("mrc p15, 1, %0, c0, c0, 0" : "=r" (val));
+	return val;
+}
+
 #endif
arch/arm/kernel/setup.c +2 -5
index 7b53500..e414f50 100644
@@ -291,12 +291,9 @@ static int cpu_has_aliasing_icache(unsigned int arch)
 	/* arch specifies the register format */
 	switch (arch) {
 	case CPU_ARCH_ARMv7:
-		asm("mcr	p15, 2, %0, c0, c0, 0 @ set CSSELR"
-		    : /* No output operands */
-		    : "r" (1));
+		set_csselr(CSSELR_ICACHE | CSSELR_L1);
 		isb();
-		asm("mrc	p15, 1, %0, c0, c0, 0 @ read CCSIDR"
-		    : "=r" (id_reg));
+		id_reg = read_ccsidr();
 		line_size = 4 << ((id_reg & 0x7) + 2);
 		num_sets = ((id_reg >> 13) & 0x7fff) + 1;
 		aliasing_icache = (line_size * num_sets) > PAGE_SIZE;
Signature · 1 line
1.7.9.5
author
#2 lore raw

PATCH 2/10 ARM: V7M: Make read_cpuid() generally available on V7M.

In reply to Vladimir Murzin

From: Jonathan Austin <[email protected]>

Previously V7M had a custom definition for read_cpuid_id that didn't use the underlying read_cpuid() macro and a stub definition for read_cpuid().

This requires a custom specialisation for each of the CPUID_* registers, and as more than just CPUID_ID may be implemented in the future this doesn't make much sense.

This patch creates a generic implementation of read_cpuid for V7M and removes the custom read_cpuid_id implementation.

Signed-off-by Jonathan Austin <[email protected]>
Signed-off-by Vladimir Murzin <[email protected]>
---
 arch/arm/include/asm/cputype.h |   50 ++++++++++++++++++++++------------------
 1 file changed, 28 insertions(+), 22 deletions(-)
arch/arm/include/asm/cputype.h +28 -22
index 1ee94c7..a689034 100644
@@ -4,15 +4,15 @@
 #include <linux/stringify.h>
 #include <linux/kernel.h>
 
-#define CPUID_ID	0
-#define CPUID_CACHETYPE	1
-#define CPUID_TCM	2
-#define CPUID_TLBTYPE	3
-#define CPUID_MPUIR	4
-#define CPUID_MPIDR	5
-#define CPUID_REVIDR	6
-
 #ifdef CONFIG_CPU_V7M
+
+#define CPUID_ID	0x0
+#define CPUID_CACHETYPE	-1
+#define CPUID_TCM	-1
+#define CPUID_TLBTYPE	-1
+#define CPUID_MPIDR	-1
+#define CPUID_REVIDR	-1
+
 #define CPUID_EXT_PFR0	0x40
 #define CPUID_EXT_PFR1	0x44
 #define CPUID_EXT_DFR0	0x48

@@ -28,6 +28,14 @@
 #define CPUID_EXT_ISAR4	0x70
 #define CPUID_EXT_ISAR5	0x74
 #else
+#define CPUID_ID	0
+#define CPUID_CACHETYPE	1
+#define CPUID_TCM	2
+#define CPUID_TLBTYPE	3
+#define CPUID_MPUIR	4
+#define CPUID_MPIDR	5
+#define CPUID_REVIDR	6
+
 #define CPUID_EXT_PFR0	"c1, 0"
 #define CPUID_EXT_PFR1	"c1, 1"
 #define CPUID_EXT_DFR0	"c1, 2"

@@ -114,11 +122,16 @@ extern unsigned int processor_id;
 #include <asm/io.h>
 #include <asm/v7m.h>
 
-#define read_cpuid(reg)							\
-	({								\
-		WARN_ON_ONCE(1);					\
-		0;							\
-	})
+static inline unsigned int __attribute_const__ read_cpuid(unsigned offset)
+{
+	switch (offset) {
+	case CPUID_ID:
+		return readl(BASEADDR_V7M_SCB + offset);
+	default:
+		WARN_ON_ONCE(1);
+		return 0;
+	}
+}
 
 static inline unsigned int __attribute_const__ read_cpuid_ext(unsigned offset)
 {

@@ -141,7 +154,7 @@ static inline unsigned int __attribute_const__ read_cpuid_ext(unsigned offset)
 
 #endif /* ifdef CONFIG_CPU_CP15 / else */
 
-#ifdef CONFIG_CPU_CP15
+#if defined(CONFIG_CPU_CP15) || defined(CONFIG_CPU_V7M)
 /*
  * The CPU ID never changes at run time, so we might as well tell the
  * compiler that it's constant.  Use this function to read the CPU ID

@@ -152,14 +165,7 @@ static inline unsigned int __attribute_const__ read_cpuid_id(void)
 	return read_cpuid(CPUID_ID);
 }
 
-#elif defined(CONFIG_CPU_V7M)
-
-static inline unsigned int __attribute_const__ read_cpuid_id(void)
-{
-	return readl(BASEADDR_V7M_SCB + V7M_SCB_CPUID);
-}
-
-#else /* ifdef CONFIG_CPU_CP15 / elif defined(CONFIG_CPU_V7M) */
+#else /* if defined(CONFIG_CPU_CP15) || defined(CONFIG_CPU_V7M) */
 
 static inline unsigned int __attribute_const__ read_cpuid_id(void)
 {
Signature · 1 line
1.7.9.5
maintainer
#3 lore raw

PATCH 2/10 ARM: V7M: Make read_cpuid() generally available on V7M.

Quoted 3 lines · Vladimir Murzin

This requires a custom specialisation for each of the CPUID_* registers, and as more than just CPUID_ID may be implemented in the future this doesn't make much sense.

You shouldn't need most of this patch. The CPUID registers are defined in such a way that unimplemented registers do not fault, but return the MIDR value. If you're just implementing MIDR, then you should just return the MIDR value and be done with it.

(Any location reading the other CPUID registers without checking whether it's a MIDR alias is probably buggy.)

Signature · 3 lines
RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up
according to speedtest.net.
author
#4 lore raw

PATCH 2/10 ARM: V7M: Make read_cpuid() generally available on V7M.

Quoted 5 lines · Russell King - ARM Linux
Quoted 3 lines · Vladimir Murzin

This requires a custom specialisation for each of the CPUID_* registers, and as more than just CPUID_ID may be implemented in the future this doesn't make much sense.

Quoted 8 lines

You shouldn't need most of this patch. The CPUID registers are defined in such a way that unimplemented registers do not fault, but return the MIDR value. If you're just implementing MIDR, then you should just return the MIDR value and be done with it.

(Any location reading the other CPUID registers without checking whether it's a MIDR alias is probably buggy.)

I'll think on it more. Thanks for feedback!

Cheers
Vladimir

author
#5 lore raw

PATCH 3/10 ARM: V7M: Add addresses for mem-mapped V7M cache operations

In reply to Vladimir Murzin

From: Jonathan Austin <[email protected]>

V7M implements cache operations similarly to V7A/R, however all operations are performed via memory-mapped IO instead of co-processor operations.

This patch adds register definitions relevant to the V7M ARM architecture's cache architecture.

Signed-off-by Jonathan Austin <[email protected]>
Signed-off-by Vladimir Murzin <[email protected]>
---
 arch/arm/include/asm/v7m.h |   22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)
arch/arm/include/asm/v7m.h +22 -0
index 615781c..1fd775c 100644
@@ -24,6 +24,9 @@
 
 #define V7M_SCB_CCR			0x14
 #define V7M_SCB_CCR_STKALIGN			(1 << 9)
+#define V7M_SCB_CCR_DC				(1 << 16)
+#define V7M_SCB_CCR_IC				(1 << 17)
+#define V7M_SCB_CCR_BP				(1 << 18)
 
 #define V7M_SCB_SHPR2			0x1c
 #define V7M_SCB_SHPR3			0x20

@@ -47,6 +50,25 @@
 #define EXC_RET_STACK_MASK			0x00000004
 #define EXC_RET_THREADMODE_PROCESSSTACK		0xfffffffd
 
+/* Cache related definitions */
+
+#define	V7M_SCB_CLIDR		0x78	/* Cache Level ID register */
+#define	V7M_SCB_CTR		0x7c	/* Cache Type register */
+#define	V7M_SCB_CCSIDR		0x80	/* Cache size ID register */
+#define	V7M_SCB_CSSELR		0x84	/* Cache size selection register */
+
+/* Cache opeartions */
+#define	V7M_SCB_ICIALLU		0x250	/* I-cache invalidate all to PoU */
+#define	V7M_SCB_ICIMVAU		0x258	/* I-cache invalidate by MVA to PoU */
+#define	V7M_SCB_DCIMVAC		0x25c	/* D-cache invalidate by MVA to PoC */
+#define	V7M_SCB_DCISW		0x260	/* D-cache invalidate by set-way */
+#define	V7M_SCB_DCCMVAU		0x264	/* D-cache clean by MVA to PoU */
+#define	V7M_SCB_DCCMVAC		0x268	/* D-cache clean by MVA to PoC */
+#define	V7M_SCB_DCCSW		0x26c	/* D-cache clean by set-way */
+#define	V7M_SCB_DCCIMVAC	0x270	/* D-cache clean and invalidate by MVA to PoC */
+#define	V7M_SCB_DCCISW		0x274	/* D-cache clean and invalidate by set-way */
+#define	V7M_SCB_BPIALL		0x278	/* D-cache clean and invalidate by set-way */
+
 #ifndef __ASSEMBLY__
 
 enum reboot_mode;
Signature · 1 line
1.7.9.5
author
#6 lore raw

PATCH 4/10 ARM: V7M: Add support for reading the CTR with CPUID_CACHETYPE

In reply to Vladimir Murzin

From: Jonathan Austin <[email protected]>

With the addition of caches to the V7M Architecture a new Cache Type Register (CTR) is defined at 0xE000ED7C. This register serves the same purpose as the V7A/R version, called CPUID_CACHETYPE in the kernel.

This patch adds appropriate definitions to the cpuid macros to allow the CTR to be read with read_cpuid(reg).

Signed-off-by Jonathan Austin <[email protected]>
Signed-off-by Vladimir Murzin <[email protected]>

---

Changelog:

RFC -> v1
- use linux/io.h instead of asm/io.h (per Russell)
- droped cast to void pointer in set_csselr; BASEADDR_V7M_SCB is already defined with a help of IOMEM macro (per Russell)

 arch/arm/include/asm/cachetype.h |   15 +++++++++++++++
 arch/arm/include/asm/cputype.h   |    3 ++-
 arch/arm/kernel/setup.c          |    9 +++++----
 3 files changed, 22 insertions(+), 5 deletions(-)
arch/arm/include/asm/cachetype.h +15 -0
index 8609de8..01509ae 100644
@@ -67,6 +67,7 @@ static inline unsigned int __attribute__((pure)) cacheid_is(unsigned int mask)
 #define CSSELR_L6	(5 << 1)
 #define CSSELR_L7	(6 << 1)
 
+#ifndef CONFIG_CPU_V7M
 static inline void set_csselr(unsigned int cache_selector)
 {
 	asm volatile("mcr p15, 2, %0, c0, c0, 0" : : "r" (cache_selector));

@@ -79,5 +80,19 @@ static inline unsigned int read_ccsidr(void)
 	asm volatile("mrc p15, 1, %0, c0, c0, 0" : "=r" (val));
 	return val;
 }
+#else /* CONFIG_CPU_V7M */
+#include <linux/io.h>
+#include "asm/v7m.h"
+
+static inline void set_csselr(unsigned int cache_selector)
+{
+	writel(cache_selector, BASEADDR_V7M_SCB + V7M_SCB_CTR);
+}
+
+static inline unsigned int read_ccsidr(void)
+{
+	return readl(BASEADDR_V7M_SCB + V7M_SCB_CCSIDR);
+}
+#endif
 
 #endif
arch/arm/include/asm/cputype.h +2 -1
index a689034..2f90cd0 100644
@@ -7,7 +7,7 @@
 #ifdef CONFIG_CPU_V7M
 
 #define CPUID_ID	0x0
-#define CPUID_CACHETYPE	-1
+#define CPUID_CACHETYPE	0x7c
 #define CPUID_TCM	-1
 #define CPUID_TLBTYPE	-1
 #define CPUID_MPIDR	-1

@@ -126,6 +126,7 @@ static inline unsigned int __attribute_const__ read_cpuid(unsigned offset)
 {
 	switch (offset) {
 	case CPUID_ID:
+	case CPUID_CACHETYPE:
 		return readl(BASEADDR_V7M_SCB + offset);
 	default:
 		WARN_ON_ONCE(1);
arch/arm/kernel/setup.c +5 -4
index e414f50..3698728 100644
@@ -313,11 +313,12 @@ static void __init cacheid_init(void)
 {
 	unsigned int arch = cpu_architecture();
 
-	if (arch == CPU_ARCH_ARMv7M) {
-		cacheid = 0;
-	} else if (arch >= CPU_ARCH_ARMv6) {
+	if (arch >= CPU_ARCH_ARMv6) {
 		unsigned int cachetype = read_cpuid_cachetype();
-		if ((cachetype & (7 << 29)) == 4 << 29) {
+
+		if ((arch == CPU_ARCH_ARMv7M) && !cachetype) {
+			cacheid = 0;
+		} else if ((cachetype & (7 << 29)) == 4 << 29) {
 			/* ARMv7 register format */
 			arch = CPU_ARCH_ARMv7;
 			cacheid = CACHEID_VIPT_NONALIASING;
Signature · 1 line
1.7.9.5
author
#7 lore raw

PATCH 5/10 ARM: Extract cp15 operations from cache flush code

In reply to Vladimir Murzin

From: Jonathan Austin <[email protected]>

Caches have been added to the V7M architecture. Instead of CP15 operations, the cache maintenance is done with memory-mapped registers. Other properties of the cache architecture are the same as V7A/R.

In order to make it possible to use the same cacheflush code on V7A/R and V7M, this commit separates out the cp15 cache maintenance operations into a separate, V7A/R specific v7 cache macros file. This is done by introducing cache macros.

This commit does not introduce any V7M-related code to simplify the process of verifying that the result of compiling cache-v7.S is identical before and after this commit.

Signed-off-by Jonathan Austin <[email protected]>
Signed-off-by Vladimir Murzin <[email protected]>

---

Changelog:

RFC -> v1

- open-coded implentation of dccmvau and icimvau instead of macros, since the latter would mark the wring instruction as user-accessable (per Russell)
- dccimvac is updated per Russell preference

arch/arm/mm/cache-v7.S | 51 +++++++----------

 arch/arm/mm/proc-macros.S     |   23 --------
 arch/arm/mm/proc-v7.S         |    1 +
 arch/arm/mm/v7-cache-macros.S |  126 +++++++++++++++++++++++++++++++++++++++++
 4 files changed, 149 insertions(+), 52 deletions(-)
 create mode 100644 arch/arm/mm/v7-cache-macros.S
arch/arm/mm/cache-v7.S +22 -29
index a134d8a..49b9bfe 100644
@@ -17,6 +17,7 @@
 #include <asm/unwind.h>
 
 #include "proc-macros.S"
+#include "v7-cache-macros.S"
 
 /*
  * The secondary kernel init calls v7_flush_dcache_all before it enables

@@ -33,9 +34,9 @@
  */
 ENTRY(v7_invalidate_l1)
        mov     r0, #0
-       mcr     p15, 2, r0, c0, c0, 0
-       mrc     p15, 1, r0, c0, c0, 0
 
+       write_csselr r0
+       read_ccsidr r0
        movw    r1, #0x7fff
        and     r2, r1, r0, lsr #13
 

@@ -55,7 +56,7 @@ ENTRY(v7_invalidate_l1)
        mov     r5, r3, lsl r1
        mov     r6, r2, lsl r0
        orr     r5, r5, r6      @ Reg = (Temp<<WayShift)|(NumSets<<SetShift)
-       mcr     p15, 0, r5, c7, c6, 2
+       dcisw   r5
        bgt     2b
        cmp     r2, #0
        bgt     1b

@@ -73,9 +74,7 @@ ENDPROC(v7_invalidate_l1)
  *	r0 - set to 0
  */
 ENTRY(v7_flush_icache_all)
-	mov	r0, #0
-	ALT_SMP(mcr	p15, 0, r0, c7, c1, 0)		@ invalidate I-cache inner shareable
-	ALT_UP(mcr	p15, 0, r0, c7, c5, 0)		@ I+BTB cache invalidate
+	invalidate_icache r0
 	ret	lr
 ENDPROC(v7_flush_icache_all)
 

@@ -89,7 +88,7 @@ ENDPROC(v7_flush_icache_all)
 
 ENTRY(v7_flush_dcache_louis)
 	dmb					@ ensure ordering with previous memory accesses
-	mrc	p15, 1, r0, c0, c0, 1		@ read clidr, r0 = clidr
+	read_clidr r0
 ALT_SMP(mov	r3, r0, lsr #20)		@ move LoUIS into position
 ALT_UP(	mov	r3, r0, lsr #26)		@ move LoUU into position
 	ands	r3, r3, #7 << 1 		@ extract LoU*2 field from clidr

@@ -117,7 +116,7 @@ ENDPROC(v7_flush_dcache_louis)
  */
 ENTRY(v7_flush_dcache_all)
 	dmb					@ ensure ordering with previous memory accesses
-	mrc	p15, 1, r0, c0, c0, 1		@ read clidr
+	read_clidr r0
 	mov	r3, r0, lsr #23			@ move LoC into position
 	ands	r3, r3, #7 << 1			@ extract LoC*2 from clidr
 	beq	finished			@ if loc is 0, then no need to clean

@@ -132,9 +131,9 @@ flush_levels:
 #ifdef CONFIG_PREEMPT
 	save_and_disable_irqs_notrace r9	@ make cssr&csidr read atomic
 #endif
-	mcr	p15, 2, r10, c0, c0, 0		@ select current cache level in cssr
+	write_csselr r10			@ set current cache level
 	isb					@ isb to sych the new cssr&csidr
-	mrc	p15, 1, r1, c0, c0, 0		@ read the new csidr
+	read_ccsidr r1				@ read the new csidr
 #ifdef CONFIG_PREEMPT
 	restore_irqs_notrace r9
 #endif

@@ -154,7 +153,7 @@ loop2:
  ARM(	orr	r11, r11, r9, lsl r2	)	@ factor index number into r11
  THUMB(	lsl	r6, r9, r2		)
  THUMB(	orr	r11, r11, r6		)	@ factor index number into r11
-	mcr	p15, 0, r11, c7, c14, 2		@ clean & invalidate by set/way
+	dccisw r11				@ clean/invalidate by set/way
 	subs	r9, r9, #1			@ decrement the index
 	bge	loop2
 	subs	r4, r4, #1			@ decrement the way

@@ -165,7 +164,7 @@ skip:
 	bgt	flush_levels
 finished:
 	mov	r10, #0				@ swith back to cache level 0
-	mcr	p15, 2, r10, c0, c0, 0		@ select current cache level in cssr
+	write_csselr r10			@ select current cache level in cssr
 	dsb	st
 	isb
 	ret	lr

@@ -186,9 +185,7 @@ ENTRY(v7_flush_kern_cache_all)
  ARM(	stmfd	sp!, {r4-r5, r7, r9-r11, lr}	)
  THUMB(	stmfd	sp!, {r4-r7, r9-r11, lr}	)
 	bl	v7_flush_dcache_all
-	mov	r0, #0
-	ALT_SMP(mcr	p15, 0, r0, c7, c1, 0)	@ invalidate I-cache inner shareable
-	ALT_UP(mcr	p15, 0, r0, c7, c5, 0)	@ I+BTB cache invalidate
+	invalidate_icache r0
  ARM(	ldmfd	sp!, {r4-r5, r7, r9-r11, lr}	)
  THUMB(	ldmfd	sp!, {r4-r7, r9-r11, lr}	)
 	ret	lr

@@ -204,9 +201,7 @@ ENTRY(v7_flush_kern_cache_louis)
  ARM(	stmfd	sp!, {r4-r5, r7, r9-r11, lr}	)
  THUMB(	stmfd	sp!, {r4-r7, r9-r11, lr}	)
 	bl	v7_flush_dcache_louis
-	mov	r0, #0
-	ALT_SMP(mcr	p15, 0, r0, c7, c1, 0)	@ invalidate I-cache inner shareable
-	ALT_UP(mcr	p15, 0, r0, c7, c5, 0)	@ I+BTB cache invalidate
+	invalidate_icache r0
  ARM(	ldmfd	sp!, {r4-r5, r7, r9-r11, lr}	)
  THUMB(	ldmfd	sp!, {r4-r7, r9-r11, lr}	)
 	ret	lr

@@ -278,7 +273,7 @@ ENTRY(v7_coherent_user_range)
 	ALT_UP(W(nop))
 #endif
 1:
- USER(	mcr	p15, 0, r12, c7, c11, 1	)	@ clean D line to the point of unification
+ USER(	dccmvau	r12 )		@ clean D line to the point of unification
 	add	r12, r12, r2
 	cmp	r12, r1
 	blo	1b

@@ -287,13 +282,11 @@ ENTRY(v7_coherent_user_range)
 	sub	r3, r2, #1
 	bic	r12, r0, r3
 2:
- USER(	mcr	p15, 0, r12, c7, c5, 1	)	@ invalidate I line
+ USER(	icimvau r12 )	@ invalidate I line
 	add	r12, r12, r2
 	cmp	r12, r1
 	blo	2b
-	mov	r0, #0
-	ALT_SMP(mcr	p15, 0, r0, c7, c1, 6)	@ invalidate BTB Inner Shareable
-	ALT_UP(mcr	p15, 0, r0, c7, c5, 6)	@ invalidate BTB
+	invalidate_bp r0
 	dsb	ishst
 	isb
 	ret	lr

@@ -331,7 +324,7 @@ ENTRY(v7_flush_kern_dcache_area)
 	ALT_UP(W(nop))
 #endif
 1:
-	mcr	p15, 0, r0, c7, c14, 1		@ clean & invalidate D line / unified line
+	dccimvac r0		@ clean & invalidate D line / unified line
 	add	r0, r0, r2
 	cmp	r0, r1
 	blo	1b

@@ -358,13 +351,13 @@ v7_dma_inv_range:
 	ALT_SMP(W(dsb))
 	ALT_UP(W(nop))
 #endif
-	mcrne	p15, 0, r0, c7, c14, 1		@ clean & invalidate D / U line
+	dccimvacne r0
 
 	tst	r1, r3
 	bic	r1, r1, r3
-	mcrne	p15, 0, r1, c7, c14, 1		@ clean & invalidate D / U line
+	dccimvacne r1
 1:
-	mcr	p15, 0, r0, c7, c6, 1		@ invalidate D / U line
+	dcimvac r0
 	add	r0, r0, r2
 	cmp	r0, r1
 	blo	1b

@@ -386,7 +379,7 @@ v7_dma_clean_range:
 	ALT_UP(W(nop))
 #endif
 1:
-	mcr	p15, 0, r0, c7, c10, 1		@ clean D / U line
+	dccmvac r0			@ clean D / U line
 	add	r0, r0, r2
 	cmp	r0, r1
 	blo	1b

@@ -408,7 +401,7 @@ ENTRY(v7_dma_flush_range)
 	ALT_UP(W(nop))
 #endif
 1:
-	mcr	p15, 0, r0, c7, c14, 1		@ clean & invalidate D / U line
+	dccimvac r0			 @ clean & invalidate D / U line
 	add	r0, r0, r2
 	cmp	r0, r1
 	blo	1b
arch/arm/mm/proc-macros.S +0 -23
index c671f34..a82800a 100644
@@ -66,29 +66,6 @@
 	.endm
 
 /*
- * dcache_line_size - get the minimum D-cache line size from the CTR register
- * on ARMv7.
- */
-	.macro	dcache_line_size, reg, tmp
-	mrc	p15, 0, \tmp, c0, c0, 1		@ read ctr
-	lsr	\tmp, \tmp, #16
-	and	\tmp, \tmp, #0xf		@ cache line size encoding
-	mov	\reg, #4			@ bytes per word
-	mov	\reg, \reg, lsl \tmp		@ actual cache line size
-	.endm
-
-/*
- * icache_line_size - get the minimum I-cache line size from the CTR register
- * on ARMv7.
- */
-	.macro	icache_line_size, reg, tmp
-	mrc	p15, 0, \tmp, c0, c0, 1		@ read ctr
-	and	\tmp, \tmp, #0xf		@ cache line size encoding
-	mov	\reg, #4			@ bytes per word
-	mov	\reg, \reg, lsl \tmp		@ actual cache line size
-	.endm
-
-/*
  * Sanity check the PTE configuration for the code below - which makes
  * certain assumptions about how these bits are laid out.
  */
arch/arm/mm/proc-v7.S +1 -0
index 6fcaac8..c7bcc0c 100644
@@ -18,6 +18,7 @@
 #include <asm/pgtable.h>
 
 #include "proc-macros.S"
+#include "v7-cache-macros.S"
 
 #ifdef CONFIG_ARM_LPAE
 #include "proc-v7-3level.S"
arch/arm/mm/v7-cache-macros.S new file +126 -0

126 lines not on this page · raw message

Signature · 1 line
1.7.9.5
author
#8 lore raw

PATCH 6/10 ARM: V7M: Implement cache macros for V7M

In reply to Vladimir Murzin

From: Jonathan Austin <[email protected]>

This commit implements the cache operation macros for V7M, paving the way for caches to be used on V7 with a future commit.

Because the cache operations in V7M are memory mapped, in most operations an extra register is required compared to the V7 version, where the type of operation is encoded in the instruction, not the address that is written to.

Thus, an extra register argument has been added to the cache operation macros, that is required in V7M but ignored/unused in V7. In almost all cases there was a spare temporary register, but in places where the register allocation was tighter the M_CLASS macro has been used to avoid clobbering new registers.

Signed-off-by Jonathan Austin <[email protected]>
Signed-off-by Vladimir Murzin <[email protected]>

---

Changelog:

RFC -> v1

- M_CLASS() macro is used instead of THUMB() where appropriate
- open-coded implentation of dccmvau and icimvau instead of macros, since the latter would mark the wrong instruction as user-accessable (per Russell)
- dccimvac is updated per Russell preference

arch/arm/mm/cache-v7.S | 48 ++++++++++----

 arch/arm/mm/v7-cache-macros.S  |   21 +++---
 arch/arm/mm/v7m-cache-macros.S |  142 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 189 insertions(+), 22 deletions(-)
 create mode 100644 arch/arm/mm/v7m-cache-macros.S
arch/arm/mm/cache-v7.S +34 -14
index 49b9bfe..4677d37 100644
@@ -17,7 +17,11 @@
 #include <asm/unwind.h>
 
 #include "proc-macros.S"
+#ifdef CONFIG_CPU_V7M
+#include "v7m-cache-macros.S"
+#else
 #include "v7-cache-macros.S"
+#endif
 
 /*
  * The secondary kernel init calls v7_flush_dcache_all before it enables

@@ -35,7 +39,7 @@
 ENTRY(v7_invalidate_l1)
        mov     r0, #0
 
-       write_csselr r0
+       write_csselr r0, r1
        read_ccsidr r0
        movw    r1, #0x7fff
        and     r2, r1, r0, lsr #13

@@ -56,7 +60,7 @@ ENTRY(v7_invalidate_l1)
        mov     r5, r3, lsl r1
        mov     r6, r2, lsl r0
        orr     r5, r5, r6      @ Reg = (Temp<<WayShift)|(NumSets<<SetShift)
-       dcisw   r5
+       dcisw   r5, r6
        bgt     2b
        cmp     r2, #0
        bgt     1b

@@ -131,7 +135,7 @@ flush_levels:
 #ifdef CONFIG_PREEMPT
 	save_and_disable_irqs_notrace r9	@ make cssr&csidr read atomic
 #endif
-	write_csselr r10			@ set current cache level
+	write_csselr r10, r1			@ set current cache level
 	isb					@ isb to sych the new cssr&csidr
 	read_ccsidr r1				@ read the new csidr
 #ifdef CONFIG_PREEMPT

@@ -153,7 +157,7 @@ loop2:
  ARM(	orr	r11, r11, r9, lsl r2	)	@ factor index number into r11
  THUMB(	lsl	r6, r9, r2		)
  THUMB(	orr	r11, r11, r6		)	@ factor index number into r11
-	dccisw r11				@ clean/invalidate by set/way
+	dccisw	r11, r6				@ clean/invalidate by set/way
 	subs	r9, r9, #1			@ decrement the index
 	bge	loop2
 	subs	r4, r4, #1			@ decrement the way

@@ -164,7 +168,7 @@ skip:
 	bgt	flush_levels
 finished:
 	mov	r10, #0				@ swith back to cache level 0
-	write_csselr r10			@ select current cache level in cssr
+	write_csselr r10, r3			@ select current cache level in cssr
 	dsb	st
 	isb
 	ret	lr

@@ -273,7 +277,17 @@ ENTRY(v7_coherent_user_range)
 	ALT_UP(W(nop))
 #endif
 1:
- USER(	dccmvau	r12 )		@ clean D line to the point of unification
+#ifdef CONFIG_CPU_V7M
+/*
+ * We use open coded version of dccmvau otherwise USER() would
+ * point at movw instruction.
+ */
+	movw	r3, #:lower16:BASEADDR_V7M_SCB + V7M_SCB_DCCMVAU
+	movt	r3, #:upper16:BASEADDR_V7M_SCB + V7M_SCB_DCCMVAU
+USER(	str	r12, [r3]	)
+#else
+USER(	dccmvau	r12		) @ clean D line to the point of unification
+#endif
 	add	r12, r12, r2
 	cmp	r12, r1
 	blo	1b

@@ -282,7 +296,13 @@ ENTRY(v7_coherent_user_range)
 	sub	r3, r2, #1
 	bic	r12, r0, r3
 2:
- USER(	icimvau r12 )	@ invalidate I line
+#ifdef CONFIG_CPU_V7M
+	movw	r3, #:lower16:BASEADDR_V7M_SCB + V7M_SCB_ICIMVAU
+	movt	r3, #:upper16:BASEADDR_V7M_SCB + V7M_SCB_ICIMVAU
+USER(	str	r12, [r3]	)
+#else
+USER(	icimvau r12		)@ invalidate I line
+#endif
 	add	r12, r12, r2
 	cmp	r12, r1
 	blo	2b

@@ -324,7 +344,7 @@ ENTRY(v7_flush_kern_dcache_area)
 	ALT_UP(W(nop))
 #endif
 1:
-	dccimvac r0		@ clean & invalidate D line / unified line
+	dccimvac r0, r3		@ clean & invalidate D line / unified line
 	add	r0, r0, r2
 	cmp	r0, r1
 	blo	1b

@@ -351,13 +371,13 @@ v7_dma_inv_range:
 	ALT_SMP(W(dsb))
 	ALT_UP(W(nop))
 #endif
-	dccimvacne r0
-
+	dccimvacne r0, r3
+M_CLASS(subne	r3, r2, #1)	@ restore r3, corrupted by v7m's dccimvac
 	tst	r1, r3
 	bic	r1, r1, r3
-	dccimvacne r1
+	dccimvacne r1, r3
 1:
-	dcimvac r0
+	dcimvac r0, r3
 	add	r0, r0, r2
 	cmp	r0, r1
 	blo	1b

@@ -379,7 +399,7 @@ v7_dma_clean_range:
 	ALT_UP(W(nop))
 #endif
 1:
-	dccmvac r0			@ clean D / U line
+	dccmvac r0, r3			@ clean D / U line
 	add	r0, r0, r2
 	cmp	r0, r1
 	blo	1b

@@ -401,7 +421,7 @@ ENTRY(v7_dma_flush_range)
 	ALT_UP(W(nop))
 #endif
 1:
-	dccimvac r0			 @ clean & invalidate D / U line
+	dccimvac r0, r3			 @ clean & invalidate D / U line
 	add	r0, r0, r2
 	cmp	r0, r1
 	blo	1b
arch/arm/mm/v7-cache-macros.S +13 -8
index 6390575..957f0c5 100644
@@ -15,6 +15,11 @@
  * Copyright (C) 2012 ARM Limited
  *
  * Author: Jonathan Austin <[email protected]>
+ *
+ * The 'unused' parameters are to keep the macro signatures in sync with the
+ * V7M versions, which require a tmp register for certain operations (see
+ * v7m-cache-macros.S). GAS supports omitting optional arguments but doesn't
+ * happily ignore additional undefined ones.
  */
 
 .macro	read_ctr, rt

@@ -29,21 +34,21 @@
 	mrc	p15, 1, \rt, c0, c0, 1
 .endm
 
-.macro	write_csselr, rt
+.macro	write_csselr, rt, unused
 	mcr     p15, 2, \rt, c0, c0, 0
 .endm
 
 /*
  * dcisw: invalidate data cache by set/way
  */
-.macro dcisw, rt
+.macro dcisw, rt, unused
 	mcr     p15, 0, \rt, c7, c6, 2
 .endm
 
 /*
  * dccisw: clean and invalidate data cache by set/way
  */
-.macro dccisw, rt
+.macro dccisw, rt, unused
 	mcr	p15, 0, \rt, c7, c14, 2
 .endm
 

@@ -51,7 +56,7 @@
  * dccimvac: Clean and invalidate data cache line by MVA to PoC.
  */
 .irp    c,,eq,ne,cs,cc,mi,pl,vs,vc,hi,ls,ge,lt,gt,le,hs,lo
-.macro	dccimvac\c, rt
+.macro	dccimvac\c, rt, unused
 	mcr\c	p15, 0, \rt, c7, c14, 1
 .endm
 .endr

@@ -59,28 +64,28 @@
 /*
  * dcimvac: Invalidate data cache line by MVA to PoC
  */
-.macro dcimvac, rt
+.macro dcimvac, rt, unused
 	mcr	p15, 0, r0, c7, c6, 1
 .endm
 
 /*
  * dccmvau: Clean data cache line by MVA to PoU
  */
-.macro dccmvau, rt
+.macro dccmvau, rt, unused
 	mcr	p15, 0, \rt, c7, c11, 1
 .endm
 
 /*
  * dccmvac: Clean data cache line by MVA to PoC
  */
-.macro dccmvac,  rt
+.macro dccmvac,  rt, unused
 	mcr	p15, 0, \rt, c7, c10, 1
 .endm
 
 /*
  * icimvau: Invalidate instruction caches by MVA to PoU
  */
-.macro icimvau, rt
+.macro icimvau, rt, unused
 	mcr	p15, 0, \rt, c7, c5, 1
 .endm
arch/arm/mm/v7m-cache-macros.S new file +142 -0

142 lines not on this page · raw message

Signature · 1 line
1.7.9.5
maintainer
#9 lore raw

PATCH 6/10 ARM: V7M: Implement cache macros for V7M

Quoted 9 lines · Vladimir Murzin

From: Jonathan Austin <[email protected]>

This commit implements the cache operation macros for V7M, paving the way for caches to be used on V7 with a future commit.

Because the cache operations in V7M are memory mapped, in most operations an extra register is required compared to the V7 version, where the type of operation is encoded in the instruction, not the address that is written to.

Quoted 5 lines

Thus, an extra register argument has been added to the cache operation macros, that is required in V7M but ignored/unused in V7. In almost all cases there was a spare temporary register, but in places where the register allocation was tighter the M_CLASS macro has been used to avoid clobbering new registers.

It's probably way more efficient to just implement this as an entirely separate implementation, rather than trying to bodge this into the v7 stuff.

Signature · 3 lines
RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up
according to speedtest.net.
author
#10 lore raw

PATCH 6/10 ARM: V7M: Implement cache macros for V7M

Quoted 16 lines · Russell King - ARM Linux
Quoted 9 lines · Vladimir Murzin

From: Jonathan Austin <[email protected]>

This commit implements the cache operation macros for V7M, paving the way for caches to be used on V7 with a future commit.

Because the cache operations in V7M are memory mapped, in most operations an extra register is required compared to the V7 version, where the type of operation is encoded in the instruction, not the address that is written to.

Quoted 5 lines

Thus, an extra register argument has been added to the cache operation macros, that is required in V7M but ignored/unused in V7. In almost all cases there was a spare temporary register, but in places where the register allocation was tighter the M_CLASS macro has been used to avoid clobbering new registers.

Quoted 4 lines

It's probably way more efficient to just implement this as an entirely separate implementation, rather than trying to bodge this into the v7 stuff.

It might be an option, but having all these as a macro make it possible to have cache support in decompresser (not presented in this series) too. If you don't buy it I'll think of moving to an entirely separate implementation as you've just suggested.

Thanks
Vladimir

maintainer
#11 lore raw

PATCH 6/10 ARM: V7M: Implement cache macros for V7M

Quoted 22 lines · Vladimir Murzin
Quoted 16 lines · Russell King - ARM Linux
Quoted 9 lines · Vladimir Murzin

From: Jonathan Austin <[email protected]>

This commit implements the cache operation macros for V7M, paving the way for caches to be used on V7 with a future commit.

Because the cache operations in V7M are memory mapped, in most operations an extra register is required compared to the V7 version, where the type of operation is encoded in the instruction, not the address that is written to.

Quoted 5 lines

Thus, an extra register argument has been added to the cache operation macros, that is required in V7M but ignored/unused in V7. In almost all cases there was a spare temporary register, but in places where the register allocation was tighter the M_CLASS macro has been used to avoid clobbering new registers.

Quoted 4 lines

It's probably way more efficient to just implement this as an entirely separate implementation, rather than trying to bodge this into the v7 stuff.

Quoted 4 lines

It might be an option, but having all these as a macro make it possible to have cache support in decompresser (not presented in this series) too. If you don't buy it I'll think of moving to an entirely separate implementation as you've just suggested.

What I really don't like is shoe-horning v7m support into cache-v7. v7m cache support should be in a separate file called cache-v7m.S.

Signature · 3 lines
RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up
according to speedtest.net.
author
#12 lore raw

PATCH 6/10 ARM: V7M: Implement cache macros for V7M

Quoted 23 lines · Russell King - ARM Linux
Quoted 22 lines · Vladimir Murzin
Quoted 20 lines · Russell King - ARM Linux
Quoted 9 lines · Vladimir Murzin

From: Jonathan Austin <[email protected]>

This commit implements the cache operation macros for V7M, paving the way for caches to be used on V7 with a future commit.

Because the cache operations in V7M are memory mapped, in most operations an extra register is required compared to the V7 version, where the type of operation is encoded in the instruction, not the address that is written to.

Quoted 5 lines

Thus, an extra register argument has been added to the cache operation macros, that is required in V7M but ignored/unused in V7. In almost all cases there was a spare temporary register, but in places where the register allocation was tighter the M_CLASS macro has been used to avoid clobbering new registers.

It's probably way more efficient to just implement this as an entirely separate implementation, rather than trying to bodge this into the v7 stuff.

Quoted 8 lines
Quoted 4 lines

It might be an option, but having all these as a macro make it possible to have cache support in decompresser (not presented in this series) too. If you don't buy it I'll think of moving to an entirely separate implementation as you've just suggested.

What I really don't like is shoe-horning v7m support into cache-v7. v7m cache support should be in a separate file called cache-v7m.S.

Your point is clear - I'll move that way then.

Cheers
Vladimir

author
#13 lore raw

PATCH 7/10 ARM: V7M: fix notrace variant of save_and_disable_irqs

In reply to Vladimir Murzin

Commit 8e43a905 "ARM: 7325/1: fix v7 boot with lockdep enabled" introduced notrace variant of save_and_disable_irqs to balance notrace variant of restore_irqs; however V7M case has been missed. It was not noticed because cache-v7.S the only place where notrace variant is used. So fix it, since we are going to extend V7 cache routines to handle V7M case too.

Signed-off-by Vladimir Murzin <[email protected]>
---
 arch/arm/include/asm/assembler.h |    4 ++++
 1 file changed, 4 insertions(+)
arch/arm/include/asm/assembler.h +4 -0
index b2bc8e1..310a5e0 100644
@@ -159,7 +159,11 @@
 	.endm
 
 	.macro	save_and_disable_irqs_notrace, oldcpsr
+#ifdef CONFIG_CPU_V7M
+	mrs	\oldcpsr, primask
+#else
 	mrs	\oldcpsr, cpsr
+#endif
 	disable_irq_notrace
 	.endm
Signature · 1 line
1.7.9.5
author
#14 lore raw

PATCH 8/10 ARM: V7M: Wire up caches for V7M processors with cache support.

In reply to Vladimir Murzin

From: Jonathan Austin <[email protected]>

This patch does the plumbing required to invoke the V7M cache code added in earlier patches in this series, although there is no users for that yet.

In order to honour the I/D cache disable config options, this patch changes the mechanism by which the CCR is set on boot, to be more like V7A/R.

Signed-off-by Jonathan Austin <[email protected]>
Signed-off-by Vladimir Murzin <[email protected]>
---
 arch/arm/include/asm/glue-cache.h |    4 ----
 arch/arm/kernel/head-nommu.S      |   16 +++++++++++++++-
 arch/arm/mm/Kconfig               |    7 ++++---
 arch/arm/mm/Makefile              |    4 ++++
 arch/arm/mm/proc-v7m.S            |    5 ++---
 5 files changed, 25 insertions(+), 11 deletions(-)
arch/arm/include/asm/glue-cache.h +0 -4
index cab07f6..01c3d92 100644
@@ -118,11 +118,7 @@
 #endif
 
 #if defined(CONFIG_CPU_V7M)
-# ifdef _CACHE
 #  define MULTI_CACHE 1
-# else
-#  define _CACHE nop
-# endif
 #endif
 
 #if !defined(_CACHE) && !defined(MULTI_CACHE)
arch/arm/kernel/head-nommu.S +15 -1
index fb1a69e..6b4eb27 100644
@@ -158,7 +158,21 @@ __after_proc_init:
 	bic	r0, r0, #CR_V
 #endif
 	mcr	p15, 0, r0, c1, c0, 0		@ write control reg
-#endif /* CONFIG_CPU_CP15 */
+#elif defined (CONFIG_CPU_V7M)
+	/* For V7M systems we want to modify the CCR similarly to the SCTLR */
+#ifdef CONFIG_CPU_DCACHE_DISABLE
+	bic	r0, r0, #V7M_SCB_CCR_DC
+#endif
+#ifdef CONFIG_CPU_BPREDICT_DISABLE
+	bic	r0, r0, #V7M_SCB_CCR_BP
+#endif
+#ifdef CONFIG_CPU_ICACHE_DISABLE
+	bic	r0, r0, #V7M_SCB_CCR_IC
+#endif
+	movw	r3, #:lower16:(BASEADDR_V7M_SCB + V7M_SCB_CCR)
+	movt	r3, #:upper16:(BASEADDR_V7M_SCB + V7M_SCB_CCR)
+	str	r0, [r3]
+#endif /* CONFIG_CPU_CP15 elif CONFIG_CPU_V7M */
 	ret	lr
 ENDPROC(__after_proc_init)
 	.ltorg
arch/arm/mm/Kconfig +4 -3
index cb569b6..50afaf0 100644
@@ -403,6 +403,7 @@ config CPU_V7M
 	bool
 	select CPU_32v7M
 	select CPU_ABRT_NOMMU
+	select CPU_CACHE_V7
 	select CPU_CACHE_NOP
 	select CPU_PABRT_LEGACY
 	select CPU_THUMBONLY

@@ -750,14 +751,14 @@ config CPU_HIGH_VECTOR
 
 config CPU_ICACHE_DISABLE
 	bool "Disable I-Cache (I-bit)"
-	depends on CPU_CP15 && !(CPU_ARM720T || CPU_ARM740T || CPU_XSCALE || CPU_XSC3)
+	depends on (CPU_CP15 && !(CPU_ARM720T || CPU_ARM740T || CPU_XSCALE || CPU_XSC3)) || CPU_V7M
 	help
 	  Say Y here to disable the processor instruction cache. Unless
 	  you have a reason not to or are unsure, say N.
 
 config CPU_DCACHE_DISABLE
 	bool "Disable D-Cache (C-bit)"
-	depends on CPU_CP15 && !SMP
+	depends on (CPU_CP15 && !SMP) || CPU_V7M
 	help
 	  Say Y here to disable the processor data cache. Unless
 	  you have a reason not to or are unsure, say N.

@@ -792,7 +793,7 @@ config CPU_CACHE_ROUND_ROBIN
 
 config CPU_BPREDICT_DISABLE
 	bool "Disable branch prediction"
-	depends on CPU_ARM1020 || CPU_V6 || CPU_V6K || CPU_MOHAWK || CPU_XSC3 || CPU_V7 || CPU_FA526
+	depends on CPU_ARM1020 || CPU_V6 || CPU_V6K || CPU_MOHAWK || CPU_XSC3 || CPU_V7 || CPU_FA526 || CPU_V7M
 	help
 	  Say Y here to disable branch prediction.  If unsure, say N.
arch/arm/mm/Makefile +4 -0
index 7f76d96..cf4709d 100644
@@ -45,7 +45,11 @@ obj-$(CONFIG_CPU_CACHE_FA)	+= cache-fa.o
 obj-$(CONFIG_CPU_CACHE_NOP)	+= cache-nop.o
 
 AFLAGS_cache-v6.o	:=-Wa,-march=armv6
+ifneq ($(CONFIG_CPU_V7M),y)
 AFLAGS_cache-v7.o	:=-Wa,-march=armv7-a
+else
+AFLAGS_cache-v7.o	:=-Wa,-march=armv7-m
+endif
 
 obj-$(CONFIG_CPU_COPY_V4WT)	+= copypage-v4wt.o
 obj-$(CONFIG_CPU_COPY_V4WB)	+= copypage-v4wb.o
arch/arm/mm/proc-v7m.S +2 -3
index 7229d8d..11f5816 100644
@@ -118,9 +118,8 @@ __v7m_setup:
 
 	@ Configure the System Control Register to ensure 8-byte stack alignment
 	@ Note the STKALIGN bit is either RW or RAO.
-	ldr	r12, [r0, V7M_SCB_CCR]	@ system control register
-	orr	r12, #V7M_SCB_CCR_STKALIGN
-	str	r12, [r0, V7M_SCB_CCR]
+	ldr	r0, [r0, V7M_SCB_CCR]   @ system control register
+	orr	r0, #V7M_SCB_CCR_STKALIGN
 	ret	lr
 ENDPROC(__v7m_setup)
Signature · 1 line
1.7.9.5
author
#15 lore raw

PATCH 9/10 ARM: V7M: Indirect proc_info construction for V7M CPUs

In reply to Vladimir Murzin

From: Jonathan Austin <[email protected]>

This patch copies the method used for V7A/R CPUs to specify differing processor info for different cores.

This patch differentiates Cortex-M3 and Cortex-M4 and leaves a fallback case for any other V7M processors.

Signed-off-by Jonathan Austin <[email protected]>
Signed-off-by Vladimir Murzin <[email protected]>
---
 arch/arm/mm/proc-v7m.S |   46 +++++++++++++++++++++++++++++++++++-----------
 1 file changed, 35 insertions(+), 11 deletions(-)
arch/arm/mm/proc-v7m.S +35 -11
index 11f5816..796a983 100644
@@ -132,6 +132,40 @@ ENDPROC(__v7m_setup)
 
 	.section ".proc.info.init", #alloc
 
+.macro __v7m_proc name, initfunc, cache_fns = nop_cache_fns, hwcaps = 0,  proc_fns = v7m_processor_functions
+	.long	0			/* proc_info_list.__cpu_mm_mmu_flags */
+	.long	0			/* proc_info_list.__cpu_io_mmu_flags */
+	initfn	\initfunc, \name
+	.long	cpu_arch_name
+	.long	cpu_elf_name
+	.long	HWCAP_HALF | HWCAP_THUMB | HWCAP_FAST_MULT | \hwcaps
+	.long	cpu_v7m_name
+	.long   \proc_fns
+	.long	0			/* proc_info_list.tlb */
+	.long	0			/* proc_info_list.user */
+	.long	\cache_fns
+.endm
+
+	/*
+	 * Match ARM Cortex-M4 processor.
+	 */
+	.type	__v7m_cm4_proc_info, #object
+__v7m_cm4_proc_info:
+	.long	0x410fc240		/* ARM Cortex-M4 0xC24 */
+	.long	0xff0ffff0		/* Mask off revision, patch release */
+	__v7m_proc __v7m_cm4_proc_info, __v7m_setup, hwcaps = HWCAP_EDSP
+	.size	__v7m_cm4_proc_info, . - __v7m_cm4_proc_info
+
+	/*
+	 * Match ARM Cortex-M3 processor.
+	 */
+	.type	__v7m_cm3_proc_info, #object
+__v7m_cm3_proc_info:
+	.long	0x410fc230		/* ARM Cortex-M3 0xC23 */
+	.long	0xff0ffff0		/* Mask off revision, patch release */
+	__v7m_proc __v7m_cm3_proc_info, __v7m_setup
+	.size	__v7m_cm3_proc_info, . - __v7m_cm3_proc_info
+
 	/*
 	 * Match any ARMv7-M processor core.
 	 */

@@ -139,16 +173,6 @@ ENDPROC(__v7m_setup)
 __v7m_proc_info:
 	.long	0x000f0000		@ Required ID value
 	.long	0x000f0000		@ Mask for ID
-	.long   0			@ proc_info_list.__cpu_mm_mmu_flags
-	.long   0			@ proc_info_list.__cpu_io_mmu_flags
-	initfn	__v7m_setup, __v7m_proc_info	@ proc_info_list.__cpu_flush
-	.long	cpu_arch_name
-	.long	cpu_elf_name
-	.long	HWCAP_HALF|HWCAP_THUMB|HWCAP_FAST_MULT
-	.long	cpu_v7m_name
-	.long	v7m_processor_functions	@ proc_info_list.proc
-	.long	0			@ proc_info_list.tlb
-	.long	0			@ proc_info_list.user
-	.long	nop_cache_fns		@ proc_info_list.cache
+	__v7m_proc __v7m_proc_info, __v7m_setup
 	.size	__v7m_proc_info, . - __v7m_proc_info
Signature · 1 line
1.7.9.5
author
#16 lore raw

PATCH 10/10 ARM: V7M: Add support for the Cortex-M7 processor

In reply to Vladimir Murzin

From: Jonathan Austin <[email protected]>

Cortex-M7 is a new member of the V7M processor family that adds, among other things, caches over the features available in Cortex-M4.

This patch adds support for recognising the processor at boot time, and make use of recently introduced cache functions.

Signed-off-by Jonathan Austin <[email protected]>
Signed-off-by Vladimir Murzin <[email protected]>
---
 arch/arm/mm/proc-v7m.S |   42 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 42 insertions(+)
arch/arm/mm/proc-v7m.S +42 -0
index 796a983..60387a0 100644
@@ -15,6 +15,7 @@
 #include <asm/memory.h>
 #include <asm/v7m.h>
 #include "proc-macros.S"
+#include "v7m-cache-macros.S"
 
 ENTRY(cpu_v7m_proc_init)
 	ret	lr

@@ -74,6 +75,25 @@ ENTRY(cpu_v7m_do_resume)
 ENDPROC(cpu_v7m_do_resume)
 #endif
 
+ENTRY(cpu_cm7_dcache_clean_area)
+	dcache_line_size r2, r3
+1:	dccmvac r0, r3				@ clean D entry
+	add	r0, r0, r2
+	subs	r1, r1, r2
+	bhi	1b
+	dsb
+	ret	lr
+ENDPROC(cpu_cm7_dcache_clean_area)
+
+ENTRY(cpu_cm7_proc_fin)
+	movw	r2, #:lower16:(BASEADDR_V7M_SCB + V7M_SCB_CCR)
+	movt	r2, #:upper16:(BASEADDR_V7M_SCB + V7M_SCB_CCR)
+	ldr	r0, [r2]
+	bic	r0, r0, #(V7M_SCB_CCR_DC | V7M_SCB_CCR_IC)
+	str	r0, [r2]
+	ret	lr
+ENDPROC(cpu_cm7_proc_fin)
+
 	.section ".text.init", #alloc, #execinstr
 
 /*

@@ -120,10 +140,22 @@ __v7m_setup:
 	@ Note the STKALIGN bit is either RW or RAO.
 	ldr	r0, [r0, V7M_SCB_CCR]   @ system control register
 	orr	r0, #V7M_SCB_CCR_STKALIGN
+	read_ctr r12
+	teq     r12, #0
+	orrne   r0, r0, #(V7M_SCB_CCR_DC | V7M_SCB_CCR_IC| V7M_SCB_CCR_BP)
 	ret	lr
 ENDPROC(__v7m_setup)
 
+/*
+ * Cortex-M7 processor functions
+ */
+	globl_equ	cpu_cm7_proc_init,	cpu_v7m_proc_init
+	globl_equ	cpu_cm7_reset,		cpu_v7m_reset
+	globl_equ	cpu_cm7_do_idle,	cpu_v7m_do_idle
+	globl_equ	cpu_cm7_switch_mm,	cpu_v7m_switch_mm
+
 	define_processor_functions v7m, dabort=nommu_early_abort, pabort=legacy_pabort, nommu=1
+	define_processor_functions cm7, dabort=nommu_early_abort, pabort=legacy_pabort, nommu=1
 
 	.section ".rodata"
 	string cpu_arch_name, "armv7m"

@@ -147,6 +179,16 @@ ENDPROC(__v7m_setup)
 .endm
 
 	/*
+	 * Match ARM Cortex-M7 processor.
+	 */
+	.type	__v7m_cm7_proc_info, #object
+__v7m_cm7_proc_info:
+	.long	0x410fc270		/* ARM Cortex-M7 0xC27 */
+	.long	0xff0ffff0		/* Mask off revision, patch release */
+	__v7m_proc __v7m_cm7_proc_info, __v7m_setup, hwcaps = HWCAP_EDSP, cache_fns = v7_cache_fns, proc_fns = cm7_processor_functions
+	.size	__v7m_cm7_proc_info, . - __v7m_cm7_proc_info
+
+	/*
 	 * Match ARM Cortex-M4 processor.
 	 */
 	.type	__v7m_cm4_proc_info, #object
Signature · 1 line
1.7.9.5
#17 lore raw

cover ARM: V7M: Support caches

In reply to Vladimir Murzin

Hi Vladimir,

Quoted 15 lines · Vladimir Murzin

Hi,

This patch set allows M-class cpus benefit of optional cache support. It originaly was written by Jonny, I've been keeping it localy mainly rebasing over Linux versions.

The main idea behind patches is to reuse existing cache handling code from v7A/R. In case v7M cache operations are provided via memory mapped interface rather than co-processor instructions, so extra macros have been introduced to factor out cache handling logic and low-level operations.

Along with the v7M cache support the first user (Cortex-M7) is introduced.

Quoted 8 lines

Patches were tested on MPS2 platform with Cortex-M3/M4/M7. The later one showed significant boot speed-up.

Based on 4.7-rc3.

Thanks!
Vladimir

Thanks for the series.
Did you change something in those patches compare to patches you sent in the RFC ?

Regards.

Alex

author
#18 lore raw

cover ARM: V7M: Support caches

Hi Alex,

Quoted 23 lines · Alexandre Torgue

Hi Vladimir,

Quoted 20 lines · Vladimir Murzin

Hi,

This patch set allows M-class cpus benefit of optional cache support. It originaly was written by Jonny, I've been keeping it localy mainly rebasing over Linux versions.

The main idea behind patches is to reuse existing cache handling code from v7A/R. In case v7M cache operations are provided via memory mapped interface rather than co-processor instructions, so extra macros have been introduced to factor out cache handling logic and low-level operations.

Along with the v7M cache support the first user (Cortex-M7) is introduced.

Patches were tested on MPS2 platform with Cortex-M3/M4/M7. The later one showed significant boot speed-up.

Based on 4.7-rc3.

Quoted 7 lines
Quoted 3 lines

Thanks!
Vladimir

Thanks for the series.
Did you change something in those patches compare to patches you sent in the RFC ?

Only 04, 05, 06 have been changed (each has it's own changelog included).

I did try to hammer patches because of your report of instability with caches on, but all run fine... so nothing has been changed in regard of your case.

Cheers
Vladimir

Quoted 7 lines

Regards.

Alex

#19 lore raw

cover ARM: V7M: Support caches

Hi Vladimir,

Quoted 34 lines · Vladimir Murzin

Hi Alex,

Quoted 23 lines · Alexandre Torgue

Hi Vladimir,

Quoted 20 lines · Vladimir Murzin

Hi,

This patch set allows M-class cpus benefit of optional cache support. It originaly was written by Jonny, I've been keeping it localy mainly rebasing over Linux versions.

The main idea behind patches is to reuse existing cache handling code from v7A/R. In case v7M cache operations are provided via memory mapped interface rather than co-processor instructions, so extra macros have been introduced to factor out cache handling logic and low-level operations.

Along with the v7M cache support the first user (Cortex-M7) is introduced.

Patches were tested on MPS2 platform with Cortex-M3/M4/M7. The later one showed significant boot speed-up.

Based on 4.7-rc3.

Quoted 7 lines
Quoted 3 lines

Thanks!
Vladimir

Thanks for the series.
Did you change something in those patches compare to patches you sent in the RFC ?

Quoted 6 lines

Only 04, 05, 06 have been changed (each has it's own changelog included).

I did try to hammer patches because of your report of instability with caches on, but all run fine... so nothing has been changed in regard of your case.

Ok. Thanks for this input. From now, I will use this series to perform my tests. I will continue to debug my instabilities this week. I will let you know.

Regards

Alex

#20 lore raw

cover ARM: V7M: Support caches

Hi Vladimir,

Quoted 39 lines · Alexandre Torgue

Hi Vladimir,

Quoted 36 lines · Vladimir Murzin

Hi Alex,

Quoted 23 lines · Alexandre Torgue

Hi Vladimir,

Quoted 20 lines · Vladimir Murzin

Hi,

This patch set allows M-class cpus benefit of optional cache support. It originaly was written by Jonny, I've been keeping it localy mainly rebasing over Linux versions.

The main idea behind patches is to reuse existing cache handling code from v7A/R. In case v7M cache operations are provided via memory mapped interface rather than co-processor instructions, so extra macros have been introduced to factor out cache handling logic and low-level operations.

Along with the v7M cache support the first user (Cortex-M7) is introduced.

Patches were tested on MPS2 platform with Cortex-M3/M4/M7. The later one showed significant boot speed-up.

Based on 4.7-rc3.

Quoted 7 lines
Quoted 3 lines

Thanks!
Vladimir

Thanks for the series.
Did you change something in those patches compare to patches you sent in the RFC ?

Only 04, 05, 06 have been changed (each has it's own changelog included).

Quoted 8 lines
Quoted 4 lines

I did try to hammer patches because of your report of instability with caches on, but all run fine... so nothing has been changed in regard of your case.

Ok. Thanks for this input. From now, I will use this series to perform my tests. I will continue to debug my instabilities this week. I will let you know.

I fixed my instabilities and it was linked to my SDRAM timings :(. I don't see behavior issues with your series (You can add my Tested-by:
Alexandre TORGUE <[email protected]>).

I have two others questions for you:

1- Maybe I didn't search deeper in the code but when you enable Dcache and Icache, what is the state of cache ? I mean we need to invalidate caches before enable it. It is done by kernel (with your patches) or it has to be done by a bootloader ?

2- I observe an issue (IMO not linked to your series) when I switch off/switch on my board. During the first boot after an hard reset I get a bus error (BFSR part in CFSR register indicates an "A bus fault on an instruction prefetch has occurred."). After SRST reset through JTAG, the kernel boot correctly.
Do you already seen this kind of issue ?

I add the backtrace and registers info.

__invalid_entry () at arch/arm/kernel/entry-v7m.S:33
33 1: b 1b
(gdb) bt
#0 __invalid_entry () at arch/arm/kernel/entry-v7m.S:33
#1 0xc000bc2a in unwind_exec_insn (ctrl=<optimized out>) at arch/arm/kernel/unwind.c:321
#2 unwind_frame (frame=0xc023d0c0 <reset_devices>) at arch/arm/kernel/unwind.c:449
#3 0xc000caec in ?? () at arch/arm/mm/cache-v7.S:69
Backtrace stopped: previous frame identical to this frame (corrupt stack?) Backtrace stopped: previous frame identical to this frame (corrupt stack?) (gdb) f 3
#3 0xc000caec in ?? () at arch/arm/mm/cache-v7.S:69
69 ret lr
(gdb) info reg

r0             0x1	1
r1             0x0	0
r2             0x1	1
r3             0x0	0
r4             0x0	0
r5             0x100	256
r6             0x0	0
r7             0xa	10
r8             0x40096	262294
r9             0x0	0
r10            0xc012b004	-1072517116
r11            0x0	0
r12            0x29	41
sp             0xc0230018	0xc0230018 <cpu_cache+4>
lr             0xc000caed	-1073689875
pc             0xc000caec	0xc000caec <v7_flush_icache_all>
xPSR           0x81000005	-2130706427

Thanks for your time.

Alex

author
#21 lore raw

cover ARM: V7M: Support caches

Quoted 48 lines · Alexandre Torgue

Hi Vladimir,

Quoted 45 lines · Alexandre Torgue

Hi Vladimir,

Quoted 42 lines · Vladimir Murzin

Hi Alex,

Quoted 23 lines · Alexandre Torgue

Hi Vladimir,

Quoted 20 lines · Vladimir Murzin

Hi,

This patch set allows M-class cpus benefit of optional cache support. It originaly was written by Jonny, I've been keeping it localy mainly rebasing over Linux versions.

The main idea behind patches is to reuse existing cache handling code from v7A/R. In case v7M cache operations are provided via memory mapped interface rather than co-processor instructions, so extra macros have been introduced to factor out cache handling logic and low-level operations.

Along with the v7M cache support the first user (Cortex-M7) is introduced.

Patches were tested on MPS2 platform with Cortex-M3/M4/M7. The later one showed significant boot speed-up.

Based on 4.7-rc3.

Quoted 8 lines
Quoted 3 lines

Thanks!
Vladimir

Thanks for the series.
Did you change something in those patches compare to patches you sent in
the RFC ?

Only 04, 05, 06 have been changed (each has it's own changelog included).

I did try to hammer patches because of your report of instability with caches on, but all run fine... so nothing has been changed in regard of your case.

Quoted 8 lines
Quoted 4 lines

Ok. Thanks for this input. From now, I will use this series to perform my tests. I will continue to debug my instabilities this week. I will let you know.

I fixed my instabilities and it was linked to my SDRAM timings :(. I don't see behavior issues with your series (You can add my Tested-by:
Alexandre TORGUE <[email protected]>).

Great! Since I have to re-work series per Russell comments I'd very appreciate your Tested-by on further versions of the patch set.

Quoted 7 lines

I have two others questions for you:

1- Maybe I didn't search deeper in the code but when you enable Dcache and Icache, what is the state of cache ? I mean we need to invalidate caches before enable it. It is done by kernel (with your patches) or it has to be done by a bootloader ?

I believe it follows A/R practice, so, yes, it is up to the bootloader to make sure that cache state is consistent.

Quoted 7 lines

2- I observe an issue (IMO not linked to your series) when I switch off/switch on my board. During the first boot after an hard reset I get a bus error (BFSR part in CFSR register indicates an "A bus fault on an instruction prefetch has occurred."). After SRST reset through JTAG, the kernel boot correctly.
Do you already seen this kind of issue ?

I didn't see anything like that, sorry.

Thanks
Vladimir

Quoted 43 lines

I add the backtrace and registers info.

__invalid_entry () at arch/arm/kernel/entry-v7m.S:33
33 1: b 1b
(gdb) bt
#0 __invalid_entry () at arch/arm/kernel/entry-v7m.S:33
#1 0xc000bc2a in unwind_exec_insn (ctrl=<optimized out>) at arch/arm/kernel/unwind.c:321
#2 unwind_frame (frame=0xc023d0c0 <reset_devices>) at arch/arm/kernel/unwind.c:449
#3 0xc000caec in ?? () at arch/arm/mm/cache-v7.S:69
Backtrace stopped: previous frame identical to this frame (corrupt stack?) Backtrace stopped: previous frame identical to this frame (corrupt stack?) (gdb) f 3
#3 0xc000caec in ?? () at arch/arm/mm/cache-v7.S:69
69 ret lr
(gdb) info reg

r0             0x1    1
r1             0x0    0
r2             0x1    1
r3             0x0    0
r4             0x0    0
r5             0x100    256
r6             0x0    0
r7             0xa    10
r8             0x40096    262294
r9             0x0    0
r10            0xc012b004    -1072517116
r11            0x0    0
r12            0x29    41
sp             0xc0230018    0xc0230018 <cpu_cache+4>
lr             0xc000caed    -1073689875
pc             0xc000caec    0xc000caec <v7_flush_icache_all>
xPSR           0x81000005    -2130706427

Thanks for your time.

Alex