* [PATCH v7 1/3] ARM: make cr_alignment read-only #ifndef CONFIG_CPU_CP15
2012-10-17 8:34 [PATCH v7 0/3] Yet another update for the Cortex-M3 series Uwe Kleine-König
@ 2012-10-17 8:34 ` Uwe Kleine-König
2013-01-15 13:08 ` Jonathan Austin
2012-10-17 8:34 ` [PATCH v7 2/3] Cortex-M3: Add base support for Cortex-M3 Uwe Kleine-König
` (2 subsequent siblings)
3 siblings, 1 reply; 11+ messages in thread
From: Uwe Kleine-König @ 2012-10-17 8:34 UTC (permalink / raw)
To: linux-arm-kernel
This makes cr_alignment a constant 0 to break code that tries to modify
the value as it's likely that it's built on wrong assumption when
CONFIG_CPU_CP15 isn't defined. For code that is only reading the value 0
is more or less a fine value to report.
Signed-off-by: Uwe Kleine-K?nig <u.kleine-koenig@pengutronix.de>
---
unchanged since v6
arch/arm/include/asm/cp15.h | 11 ++++++++++-
arch/arm/kernel/head-common.S | 9 +++++++--
arch/arm/mm/alignment.c | 2 ++
arch/arm/mm/mmu.c | 17 +++++++++++++++++
4 files changed, 36 insertions(+), 3 deletions(-)
diff --git a/arch/arm/include/asm/cp15.h b/arch/arm/include/asm/cp15.h
index 5ef4d80..d814435 100644
--- a/arch/arm/include/asm/cp15.h
+++ b/arch/arm/include/asm/cp15.h
@@ -42,6 +42,8 @@
#define vectors_high() (0)
#endif
+#ifdef CONFIG_CPU_CP15
+
extern unsigned long cr_no_alignment; /* defined in entry-armv.S */
extern unsigned long cr_alignment; /* defined in entry-armv.S */
@@ -82,6 +84,13 @@ static inline void set_copro_access(unsigned int val)
isb();
}
-#endif
+#else /* ifdef CONFIG_CPU_CP15 */
+
+#define cr_no_alignment UL(0)
+#define cr_alignment UL(0)
+
+#endif /* ifdef CONFIG_CPU_CP15 / else */
+
+#endif /* ifndef __ASSEMBLY__ */
#endif
diff --git a/arch/arm/kernel/head-common.S b/arch/arm/kernel/head-common.S
index 854bd22..2f560c5 100644
--- a/arch/arm/kernel/head-common.S
+++ b/arch/arm/kernel/head-common.S
@@ -98,8 +98,9 @@ __mmap_switched:
str r9, [r4] @ Save processor ID
str r1, [r5] @ Save machine type
str r2, [r6] @ Save atags pointer
- bic r4, r0, #CR_A @ Clear 'A' bit
- stmia r7, {r0, r4} @ Save control register values
+ cmp r7, #0
+ bicne r4, r0, #CR_A @ Clear 'A' bit
+ stmneia r7, {r0, r4} @ Save control register values
b start_kernel
ENDPROC(__mmap_switched)
@@ -113,7 +114,11 @@ __mmap_switched_data:
.long processor_id @ r4
.long __machine_arch_type @ r5
.long __atags_pointer @ r6
+#ifdef CONFIG_CPU_CP15
.long cr_alignment @ r7
+#else
+ .long 0
+#endif
.long init_thread_union + THREAD_START_SP @ sp
.size __mmap_switched_data, . - __mmap_switched_data
diff --git a/arch/arm/mm/alignment.c b/arch/arm/mm/alignment.c
index b9f60eb..5748094 100644
--- a/arch/arm/mm/alignment.c
+++ b/arch/arm/mm/alignment.c
@@ -962,12 +962,14 @@ static int __init alignment_init(void)
return -ENOMEM;
#endif
+#ifdef CONFIG_CPU_CP15
if (cpu_is_v6_unaligned()) {
cr_alignment &= ~CR_A;
cr_no_alignment &= ~CR_A;
set_cr(cr_alignment);
ai_usermode = safe_usermode(ai_usermode, false);
}
+#endif
hook_fault_code(FAULT_CODE_ALIGNMENT, do_alignment, SIGBUS, BUS_ADRALN,
"alignment exception");
diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
index 941dfb9..b675918 100644
--- a/arch/arm/mm/mmu.c
+++ b/arch/arm/mm/mmu.c
@@ -97,6 +97,7 @@ static struct cachepolicy cache_policies[] __initdata = {
}
};
+#ifdef CONFIG_CPU_CP15
/*
* These are useful for identifying cache coherency
* problems by allowing the cache or the cache and
@@ -195,6 +196,22 @@ void adjust_cr(unsigned long mask, unsigned long set)
}
#endif
+#else
+
+static int __init early_cachepolicy(char *p)
+{
+ pr_warning("cachepolicy kernel parameter not supported without cp15\n");
+}
+early_param("cachepolicy", early_cachepolicy);
+
+static int __init noalign_setup(char *__unused)
+{
+ pr_warning("noalign kernel parameter not supported without cp15\n");
+}
+__setup("noalign", noalign_setup);
+
+#endif
+
#define PROT_PTE_DEVICE L_PTE_PRESENT|L_PTE_YOUNG|L_PTE_DIRTY|L_PTE_XN
#define PROT_SECT_DEVICE PMD_TYPE_SECT|PMD_SECT_AP_WRITE
--
1.7.10.4
^ permalink raw reply related [flat|nested] 11+ messages in thread* [PATCH v7 1/3] ARM: make cr_alignment read-only #ifndef CONFIG_CPU_CP15
2012-10-17 8:34 ` [PATCH v7 1/3] ARM: make cr_alignment read-only #ifndef CONFIG_CPU_CP15 Uwe Kleine-König
@ 2013-01-15 13:08 ` Jonathan Austin
2013-01-16 12:03 ` Uwe Kleine-König
0 siblings, 1 reply; 11+ messages in thread
From: Jonathan Austin @ 2013-01-15 13:08 UTC (permalink / raw)
To: linux-arm-kernel
Hi Uwe,
On 17/10/12 09:34, Uwe Kleine-K?nig wrote:
> This makes cr_alignment a constant 0 to break code that tries to modify
> the value as it's likely that it's built on wrong assumption when
> CONFIG_CPU_CP15 isn't defined. For code that is only reading the value 0
> is more or less a fine value to report.
>
Without the context of some of the discussion that was had on the list
about how/why to do this, this description is a bit confusing...
I found myself asking "Why do we not #ifdef out uses of cr_alignment
based on CONFIG_CPU_CP15" - a question which it seems is answered by you
and Nicolas here:
http://lists.infradead.org/pipermail/linux-arm-kernel/2012-March/089968.html
So, perhaps it would help to have a little bit more context in this
commit message?
I know that the cr_alignment stuff is currently tied up with
CONFIG_CPU_15, but I wonder if you looked at using the CCR.UNALIGN_TRP
bit and wiring that in to alignment trapping code? Is it something you
think would make sense for the work you're doing?
Also, see a couple of minor style/commenting points below...
> Signed-off-by: Uwe Kleine-K?nig <u.kleine-koenig@pengutronix.de>
> ---
> unchanged since v6
> arch/arm/include/asm/cp15.h | 11 ++++++++++-
> arch/arm/kernel/head-common.S | 9 +++++++--
> arch/arm/mm/alignment.c | 2 ++
> arch/arm/mm/mmu.c | 17 +++++++++++++++++
> 4 files changed, 36 insertions(+), 3 deletions(-)
>
> diff --git a/arch/arm/include/asm/cp15.h b/arch/arm/include/asm/cp15.h
> index 5ef4d80..d814435 100644
> --- a/arch/arm/include/asm/cp15.h
> +++ b/arch/arm/include/asm/cp15.h
> @@ -42,6 +42,8 @@
> #define vectors_high() (0)
> #endif
>
> +#ifdef CONFIG_CPU_CP15
> +
> extern unsigned long cr_no_alignment; /* defined in entry-armv.S */
> extern unsigned long cr_alignment; /* defined in entry-armv.S */
>
> @@ -82,6 +84,13 @@ static inline void set_copro_access(unsigned int val)
> isb();
> }
>
> -#endif
> +#else /* ifdef CONFIG_CPU_CP15 */
> +
> +#define cr_no_alignment UL(0)
> +#define cr_alignment UL(0)
> +
> +#endif /* ifdef CONFIG_CPU_CP15 / else */
> +
> +#endif /* ifndef __ASSEMBLY__ */
>
> #endif
> diff --git a/arch/arm/kernel/head-common.S b/arch/arm/kernel/head-common.S
> index 854bd22..2f560c5 100644
> --- a/arch/arm/kernel/head-common.S
> +++ b/arch/arm/kernel/head-common.S
> @@ -98,8 +98,9 @@ __mmap_switched:
> str r9, [r4] @ Save processor ID
> str r1, [r5] @ Save machine type
> str r2, [r6] @ Save atags pointer
> - bic r4, r0, #CR_A @ Clear 'A' bit
> - stmia r7, {r0, r4} @ Save control register values
> + cmp r7, #0
> + bicne r4, r0, #CR_A @ Clear 'A' bit
> + stmneia r7, {r0, r4} @ Save control register values
> b start_kernel
> ENDPROC(__mmap_switched)
>
> @@ -113,7 +114,11 @@ __mmap_switched_data:
> .long processor_id @ r4
> .long __machine_arch_type @ r5
> .long __atags_pointer @ r6
> +#ifdef CONFIG_CPU_CP15
> .long cr_alignment @ r7
> +#else
> + .long 0
This value still gets loaded in to r7, so it might be worth keeping the
comments going... They certainly help when reading the code.
> +#endif
> .long init_thread_union + THREAD_START_SP @ sp
> .size __mmap_switched_data, . - __mmap_switched_data
>
> diff --git a/arch/arm/mm/alignment.c b/arch/arm/mm/alignment.c
> index b9f60eb..5748094 100644
> --- a/arch/arm/mm/alignment.c
> +++ b/arch/arm/mm/alignment.c
> @@ -962,12 +962,14 @@ static int __init alignment_init(void)
> return -ENOMEM;
> #endif
>
> +#ifdef CONFIG_CPU_CP15
> if (cpu_is_v6_unaligned()) {
> cr_alignment &= ~CR_A;
> cr_no_alignment &= ~CR_A;
> set_cr(cr_alignment);
> ai_usermode = safe_usermode(ai_usermode, false);
> }
> +#endif
>
> hook_fault_code(FAULT_CODE_ALIGNMENT, do_alignment, SIGBUS, BUS_ADRALN,
> "alignment exception");
> diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
> index 941dfb9..b675918 100644
> --- a/arch/arm/mm/mmu.c
> +++ b/arch/arm/mm/mmu.c
> @@ -97,6 +97,7 @@ static struct cachepolicy cache_policies[] __initdata = {
> }
> };
>
> +#ifdef CONFIG_CPU_CP15
> /*
> * These are useful for identifying cache coherency
> * problems by allowing the cache or the cache and
> @@ -195,6 +196,22 @@ void adjust_cr(unsigned long mask, unsigned long set)
> }
> #endif
>
> +#else
When you read this file in its complete form there's a lot of code
(including more preprocessor stuff) between the #ifdef and the #else.
Could you add
#else /* ifdef CONFIG_CPU_CP15 */
like you have in the other cases?
Jonny
^ permalink raw reply [flat|nested] 11+ messages in thread* [PATCH v7 1/3] ARM: make cr_alignment read-only #ifndef CONFIG_CPU_CP15
2013-01-15 13:08 ` Jonathan Austin
@ 2013-01-16 12:03 ` Uwe Kleine-König
0 siblings, 0 replies; 11+ messages in thread
From: Uwe Kleine-König @ 2013-01-16 12:03 UTC (permalink / raw)
To: linux-arm-kernel
Hello Jonny,
On Tue, Jan 15, 2013 at 01:08:20PM +0000, Jonathan Austin wrote:
> On 17/10/12 09:34, Uwe Kleine-K?nig wrote:
> >This makes cr_alignment a constant 0 to break code that tries to modify
> >the value as it's likely that it's built on wrong assumption when
> >CONFIG_CPU_CP15 isn't defined. For code that is only reading the value 0
> >is more or less a fine value to report.
> >
>
> Without the context of some of the discussion that was had on the
> list about how/why to do this, this description is a bit
> confusing...
>
> I found myself asking "Why do we not #ifdef out uses of cr_alignment
> based on CONFIG_CPU_CP15" - a question which it seems is answered by
> you and Nicolas here:
>
> http://lists.infradead.org/pipermail/linux-arm-kernel/2012-March/089968.html
>
> So, perhaps it would help to have a little bit more context in this
> commit message?
>
> I know that the cr_alignment stuff is currently tied up with
> CONFIG_CPU_15, but I wonder if you looked at using the
> CCR.UNALIGN_TRP bit and wiring that in to alignment trapping code?
> Is it something you think would make sense for the work you're
> doing?
I didn't, because I focus on getting the machine up and add bells and
whistles later.
> >+#ifdef CONFIG_CPU_CP15
> > .long cr_alignment @ r7
> >+#else
> >+ .long 0
>
> This value still gets loaded in to r7, so it might be worth keeping
> the comments going... They certainly help when reading the code.
ok
> >--- a/arch/arm/mm/mmu.c
> >+++ b/arch/arm/mm/mmu.c
> >@@ -97,6 +97,7 @@ static struct cachepolicy cache_policies[] __initdata = {
> > }
> > };
> >
> >+#ifdef CONFIG_CPU_CP15
> > /*
> > * These are useful for identifying cache coherency
> > * problems by allowing the cache or the cache and
> >@@ -195,6 +196,22 @@ void adjust_cr(unsigned long mask, unsigned long set)
> > }
> > #endif
> >
> >+#else
>
> When you read this file in its complete form there's a lot of code
> (including more preprocessor stuff) between the #ifdef and the
> #else.
>
> Could you add
>
> #else /* ifdef CONFIG_CPU_CP15 */
>
> like you have in the other cases?
also ok.
Will fix up after lunch.
Best regards
Uwe
--
Pengutronix e.K. | Uwe Kleine-K?nig |
Industrial Linux Solutions | http://www.pengutronix.de/ |
^ permalink raw reply [flat|nested] 11+ messages in thread
* [PATCH v7 2/3] Cortex-M3: Add base support for Cortex-M3
2012-10-17 8:34 [PATCH v7 0/3] Yet another update for the Cortex-M3 series Uwe Kleine-König
2012-10-17 8:34 ` [PATCH v7 1/3] ARM: make cr_alignment read-only #ifndef CONFIG_CPU_CP15 Uwe Kleine-König
@ 2012-10-17 8:34 ` Uwe Kleine-König
2012-10-17 8:34 ` [PATCH v7 3/3] Cortex-M3: Add support for exception handling Uwe Kleine-König
2013-01-11 9:47 ` [PATCH v7 0/3] Yet another update for the Cortex-M3 series Uwe Kleine-König
3 siblings, 0 replies; 11+ messages in thread
From: Uwe Kleine-König @ 2012-10-17 8:34 UTC (permalink / raw)
To: linux-arm-kernel
From: Catalin Marinas <catalin.marinas@arm.com>
This patch adds the base support for the Cortex-M3 processor (ARMv7-M
architecture). It consists of the corresponding arch/arm/mm/ files and
various #ifdef's around the kernel. Exception handling is implemented by
a subsequent patch.
[ukleinek: squash in some changes originating from commit
b5717ba (Cortex-M3: Add support for the Microcontroller Prototyping System)
from the v2.6.33-arm1 patch stack, port to post 3.6, drop zImage
support, drop reorganisation of pt_regs, assert CONFIG_V7M doesn't leak
into installed headers and a few cosmetic changes]
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Uwe Kleine-K?nig <u.kleine-koenig@pengutronix.de>
---
changes since v6:
- trivially rebased on v3.7-rc1
arch/arm/include/asm/assembler.h | 13 ++-
arch/arm/include/asm/cputype.h | 3 +
arch/arm/include/asm/glue-cache.h | 25 ++++++
arch/arm/include/asm/glue-df.h | 8 ++
arch/arm/include/asm/glue-proc.h | 9 ++
arch/arm/include/asm/irqflags.h | 22 +++--
arch/arm/include/asm/processor.h | 7 ++
arch/arm/include/asm/ptrace.h | 8 ++
arch/arm/include/asm/system_info.h | 1 +
arch/arm/include/uapi/asm/ptrace.h | 36 ++++++--
arch/arm/kernel/asm-offsets.c | 3 +
arch/arm/kernel/head-nommu.S | 9 +-
arch/arm/kernel/setup.c | 13 ++-
arch/arm/kernel/traps.c | 2 +
arch/arm/mm/nommu.c | 2 +
arch/arm/mm/proc-v7m.S | 161 ++++++++++++++++++++++++++++++++++++
16 files changed, 303 insertions(+), 19 deletions(-)
create mode 100644 arch/arm/mm/proc-v7m.S
diff --git a/arch/arm/include/asm/assembler.h b/arch/arm/include/asm/assembler.h
index 2ef9581..ab7c02c 100644
--- a/arch/arm/include/asm/assembler.h
+++ b/arch/arm/include/asm/assembler.h
@@ -136,7 +136,11 @@
* assumes FIQs are enabled, and that the processor is in SVC mode.
*/
.macro save_and_disable_irqs, oldcpsr
+#ifdef CONFIG_CPU_V7M
+ mrs \oldcpsr, primask
+#else
mrs \oldcpsr, cpsr
+#endif
disable_irq
.endm
@@ -150,7 +154,11 @@
* guarantee that this will preserve the flags.
*/
.macro restore_irqs_notrace, oldcpsr
+#ifdef CONFIG_CPU_V7M
+ msr primask, \oldcpsr
+#else
msr cpsr_c, \oldcpsr
+#endif
.endm
.macro restore_irqs, oldcpsr
@@ -229,7 +237,10 @@
#endif
.endm
-#ifdef CONFIG_THUMB2_KERNEL
+#if defined(CONFIG_CPU_V7M)
+ .macro setmode, mode, reg
+ .endm
+#elif defined(CONFIG_THUMB2_KERNEL)
.macro setmode, mode, reg
mov \reg, #\mode
msr cpsr_c, \reg
diff --git a/arch/arm/include/asm/cputype.h b/arch/arm/include/asm/cputype.h
index cb47d28..5bd8cb6 100644
--- a/arch/arm/include/asm/cputype.h
+++ b/arch/arm/include/asm/cputype.h
@@ -46,6 +46,9 @@ extern unsigned int processor_id;
: "cc"); \
__val; \
})
+#elif defined(CONFIG_CPU_V7M)
+#define read_cpuid(reg) (*(unsigned int *)0xe000ed00)
+#define read_cpuid_ext(reg) 0
#else
#define read_cpuid(reg) (processor_id)
#define read_cpuid_ext(reg) 0
diff --git a/arch/arm/include/asm/glue-cache.h b/arch/arm/include/asm/glue-cache.h
index cca9f15..ea98658 100644
--- a/arch/arm/include/asm/glue-cache.h
+++ b/arch/arm/include/asm/glue-cache.h
@@ -125,10 +125,35 @@
# endif
#endif
+#if defined(CONFIG_CPU_V7M)
+# ifdef _CACHE
+# error "Multi-cache not supported on ARMv7-M"
+# else
+# define _CACHE nop
+# endif
+#endif
+
#if !defined(_CACHE) && !defined(MULTI_CACHE)
#error Unknown cache maintenance model
#endif
+#ifndef __ASSEMBLER__
+static inline void nop_flush_icache_all(void) { }
+static inline void nop_flush_kern_cache_all(void) { }
+static inline void nop_flush_kern_cache_louis(void) { }
+static inline void nop_flush_user_cache_all(void) { }
+static inline void nop_flush_user_cache_range(unsigned long a, unsigned long b, unsigned int c) { }
+
+static inline void nop_coherent_kern_range(unsigned long a, unsigned long b) { }
+static inline int nop_coherent_user_range(unsigned long a, unsigned long b) { return 0; }
+static inline void nop_flush_kern_dcache_area(void *a, size_t s) { }
+
+static inline void nop_dma_flush_range(const void *a, const void *b) { }
+
+static inline void nop_dma_map_area(const void *s, size_t l, int f) { }
+static inline void nop_dma_unmap_area(const void *s, size_t l, int f) { }
+#endif
+
#ifndef MULTI_CACHE
#define __cpuc_flush_icache_all __glue(_CACHE,_flush_icache_all)
#define __cpuc_flush_kern_all __glue(_CACHE,_flush_kern_cache_all)
diff --git a/arch/arm/include/asm/glue-df.h b/arch/arm/include/asm/glue-df.h
index 8cacbcd..1f2339c 100644
--- a/arch/arm/include/asm/glue-df.h
+++ b/arch/arm/include/asm/glue-df.h
@@ -95,6 +95,14 @@
# endif
#endif
+#ifdef CONFIG_CPU_ABRT_NOMMU
+# ifdef CPU_DABORT_HANDLER
+# define MULTI_DABORT 1
+# else
+# define CPU_DABORT_HANDLER nommu_early_abort
+# endif
+#endif
+
#ifndef CPU_DABORT_HANDLER
#error Unknown data abort handler type
#endif
diff --git a/arch/arm/include/asm/glue-proc.h b/arch/arm/include/asm/glue-proc.h
index ac1dd54..f2f39bc 100644
--- a/arch/arm/include/asm/glue-proc.h
+++ b/arch/arm/include/asm/glue-proc.h
@@ -230,6 +230,15 @@
# endif
#endif
+#ifdef CONFIG_CPU_V7M
+# ifdef CPU_NAME
+# undef MULTI_CPU
+# define MULTI_CPU
+# else
+# define CPU_NAME cpu_v7m
+# endif
+#endif
+
#ifndef MULTI_CPU
#define cpu_proc_init __glue(CPU_NAME,_proc_init)
#define cpu_proc_fin __glue(CPU_NAME,_proc_fin)
diff --git a/arch/arm/include/asm/irqflags.h b/arch/arm/include/asm/irqflags.h
index 1e6cca5..3b763d6 100644
--- a/arch/arm/include/asm/irqflags.h
+++ b/arch/arm/include/asm/irqflags.h
@@ -8,6 +8,16 @@
/*
* CPU interrupt mask handling.
*/
+#ifdef CONFIG_CPU_V7M
+#define IRQMASK_REG_NAME_R "primask"
+#define IRQMASK_REG_NAME_W "primask"
+#define IRQMASK_I_BIT 1
+#else
+#define IRQMASK_REG_NAME_R "cpsr"
+#define IRQMASK_REG_NAME_W "cpsr_c"
+#define IRQMASK_I_BIT PSR_I_BIT
+#endif
+
#if __LINUX_ARM_ARCH__ >= 6
static inline unsigned long arch_local_irq_save(void)
@@ -15,7 +25,7 @@ static inline unsigned long arch_local_irq_save(void)
unsigned long flags;
asm volatile(
- " mrs %0, cpsr @ arch_local_irq_save\n"
+ " mrs %0, " IRQMASK_REG_NAME_R " @ arch_local_irq_save\n"
" cpsid i"
: "=r" (flags) : : "memory", "cc");
return flags;
@@ -129,7 +139,7 @@ static inline unsigned long arch_local_save_flags(void)
{
unsigned long flags;
asm volatile(
- " mrs %0, cpsr @ local_save_flags"
+ " mrs %0, " IRQMASK_REG_NAME_R " @ local_save_flags"
: "=r" (flags) : : "memory", "cc");
return flags;
}
@@ -140,7 +150,7 @@ static inline unsigned long arch_local_save_flags(void)
static inline void arch_local_irq_restore(unsigned long flags)
{
asm volatile(
- " msr cpsr_c, %0 @ local_irq_restore"
+ " msr " IRQMASK_REG_NAME_W ", %0 @ local_irq_restore"
:
: "r" (flags)
: "memory", "cc");
@@ -148,8 +158,8 @@ static inline void arch_local_irq_restore(unsigned long flags)
static inline int arch_irqs_disabled_flags(unsigned long flags)
{
- return flags & PSR_I_BIT;
+ return flags & IRQMASK_I_BIT;
}
-#endif
-#endif
+#endif /* ifdef __KERNEL__ */
+#endif /* ifndef __ASM_ARM_IRQFLAGS_H */
diff --git a/arch/arm/include/asm/processor.h b/arch/arm/include/asm/processor.h
index 06e7d50..5e61b88 100644
--- a/arch/arm/include/asm/processor.h
+++ b/arch/arm/include/asm/processor.h
@@ -49,7 +49,14 @@ struct thread_struct {
#ifdef CONFIG_MMU
#define nommu_start_thread(regs) do { } while (0)
#else
+#ifndef CONFIG_CPU_V7M
#define nommu_start_thread(regs) regs->ARM_r10 = current->mm->start_data
+#else
+#define nommu_start_thread(regs) do { \
+ regs->ARM_r10 = current->mm->start_data; \
+ regs->ARM_EXC_RET = 0xfffffffdL; \
+} while (0)
+#endif
#endif
#define start_thread(regs,pc,sp) \
diff --git a/arch/arm/include/asm/ptrace.h b/arch/arm/include/asm/ptrace.h
index 3d52ee1..67661e8 100644
--- a/arch/arm/include/asm/ptrace.h
+++ b/arch/arm/include/asm/ptrace.h
@@ -14,7 +14,11 @@
#ifndef __ASSEMBLY__
struct pt_regs {
+#ifdef CONFIG_CPU_V7M
+ unsigned long uregs[20];
+#else
unsigned long uregs[18];
+#endif
};
#define user_mode(regs) \
@@ -45,6 +49,7 @@ struct pt_regs {
*/
static inline int valid_user_regs(struct pt_regs *regs)
{
+#ifndef CONFIG_CPU_V7M
unsigned long mode = regs->ARM_cpsr & MODE_MASK;
/*
@@ -67,6 +72,9 @@ static inline int valid_user_regs(struct pt_regs *regs)
regs->ARM_cpsr |= USR_MODE;
return 0;
+#else /* ifndef CONFIG_CPU_V7M */
+ return 1;
+#endif
}
static inline long regs_return_value(struct pt_regs *regs)
diff --git a/arch/arm/include/asm/system_info.h b/arch/arm/include/asm/system_info.h
index dfd386d..720ea03 100644
--- a/arch/arm/include/asm/system_info.h
+++ b/arch/arm/include/asm/system_info.h
@@ -11,6 +11,7 @@
#define CPU_ARCH_ARMv5TEJ 7
#define CPU_ARCH_ARMv6 8
#define CPU_ARCH_ARMv7 9
+#define CPU_ARCH_ARMv7M 10
#ifndef __ASSEMBLY__
diff --git a/arch/arm/include/uapi/asm/ptrace.h b/arch/arm/include/uapi/asm/ptrace.h
index 96ee092..2ae7d1b 100644
--- a/arch/arm/include/uapi/asm/ptrace.h
+++ b/arch/arm/include/uapi/asm/ptrace.h
@@ -34,28 +34,47 @@
/*
* PSR bits
+ * Note on V7M there is no mode contained in the PSR
*/
#define USR26_MODE 0x00000000
#define FIQ26_MODE 0x00000001
#define IRQ26_MODE 0x00000002
#define SVC26_MODE 0x00000003
+#if defined(__KERNEL__) && defined(CONFIG_CPU_V7M)
+/*
+ * Use 0 here to get code right that creates a userspace
+ * or kernel space thread.
+ */
+#define USR_MODE 0x00000000
+#define SVC_MODE 0x00000000
+#else
#define USR_MODE 0x00000010
+#define SVC_MODE 0x00000013
+#endif
#define FIQ_MODE 0x00000011
#define IRQ_MODE 0x00000012
-#define SVC_MODE 0x00000013
#define ABT_MODE 0x00000017
#define HYP_MODE 0x0000001a
#define UND_MODE 0x0000001b
#define SYSTEM_MODE 0x0000001f
#define MODE32_BIT 0x00000010
#define MODE_MASK 0x0000001f
-#define PSR_T_BIT 0x00000020
-#define PSR_F_BIT 0x00000040
-#define PSR_I_BIT 0x00000080
-#define PSR_A_BIT 0x00000100
-#define PSR_E_BIT 0x00000200
-#define PSR_J_BIT 0x01000000
-#define PSR_Q_BIT 0x08000000
+
+#define V4_PSR_T_BIT 0x00000020 /* >= V4T, but not V7M */
+#define V7M_PSR_T_BIT 0x01000000
+#if defined(__KERNEL__) && defined(CONFIG_CPU_V7M)
+#define PSR_T_BIT V7M_PSR_T_BIT
+#else
+/* for compatibility */
+#define PSR_T_BIT V4_PSR_T_BIT
+#endif
+
+#define PSR_F_BIT 0x00000040 /* >= V4, but not V7M */
+#define PSR_I_BIT 0x00000080 /* >= V4, but not V7M */
+#define PSR_A_BIT 0x00000100 /* >= V6, but not V7M */
+#define PSR_E_BIT 0x00000200 /* >= V6, but not V7M */
+#define PSR_J_BIT 0x01000000 /* >= V5J, but not V7M */
+#define PSR_Q_BIT 0x08000000 /* >= V5E, including V7M */
#define PSR_V_BIT 0x10000000
#define PSR_C_BIT 0x20000000
#define PSR_Z_BIT 0x40000000
@@ -125,6 +144,7 @@ struct pt_regs {
#define ARM_r1 uregs[1]
#define ARM_r0 uregs[0]
#define ARM_ORIG_r0 uregs[17]
+#define ARM_EXC_RET uregs[18]
/*
* The size of the user-visible VFP state as seen by PTRACE_GET/SETVFPREGS
diff --git a/arch/arm/kernel/asm-offsets.c b/arch/arm/kernel/asm-offsets.c
index c985b48..5fe9ace 100644
--- a/arch/arm/kernel/asm-offsets.c
+++ b/arch/arm/kernel/asm-offsets.c
@@ -93,6 +93,9 @@ int main(void)
DEFINE(S_PC, offsetof(struct pt_regs, ARM_pc));
DEFINE(S_PSR, offsetof(struct pt_regs, ARM_cpsr));
DEFINE(S_OLD_R0, offsetof(struct pt_regs, ARM_ORIG_r0));
+#ifdef CONFIG_CPU_V7M
+ DEFINE(S_EXC_RET, offsetof(struct pt_regs, ARM_EXC_RET));
+#endif
DEFINE(S_FRAME_SIZE, sizeof(struct pt_regs));
BLANK();
#ifdef CONFIG_CACHE_L2X0
diff --git a/arch/arm/kernel/head-nommu.S b/arch/arm/kernel/head-nommu.S
index 278cfc1..c391c05 100644
--- a/arch/arm/kernel/head-nommu.S
+++ b/arch/arm/kernel/head-nommu.S
@@ -44,10 +44,13 @@ ENTRY(stext)
setmode PSR_F_BIT | PSR_I_BIT | SVC_MODE, r9 @ ensure svc mode
@ and irqs disabled
-#ifndef CONFIG_CPU_CP15
- ldr r9, =CONFIG_PROCESSOR_ID
-#else
+#if defined(CONFIG_CPU_CP15)
mrc p15, 0, r9, c0, c0 @ get processor id
+#elif defined(CONFIG_CPU_V7M)
+ ldr r9, =0xe000ed00 @ CPUID register address
+ ldr r9, [r9]
+#else
+ ldr r9, =CONFIG_PROCESSOR_ID
#endif
bl __lookup_processor_type @ r5=procinfo r9=cpuid
movs r10, r5 @ invalid processor (r5=0)?
diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c
index da1d1aa..3cca0c8 100644
--- a/arch/arm/kernel/setup.c
+++ b/arch/arm/kernel/setup.c
@@ -128,7 +128,9 @@ struct stack {
u32 und[3];
} ____cacheline_aligned;
+#ifndef CONFIG_CPU_V7M
static struct stack stacks[NR_CPUS];
+#endif
char elf_platform[ELF_PLATFORM_SIZE];
EXPORT_SYMBOL(elf_platform);
@@ -207,7 +209,7 @@ static const char *proc_arch[] = {
"5TEJ",
"6TEJ",
"7",
- "?(11)",
+ "7M",
"?(12)",
"?(13)",
"?(14)",
@@ -216,6 +218,12 @@ static const char *proc_arch[] = {
"?(17)",
};
+#ifdef CONFIG_CPU_V7M
+static int __get_cpu_architecture(void)
+{
+ return CPU_ARCH_ARMv7M;
+}
+#else
static int __get_cpu_architecture(void)
{
int cpu_arch;
@@ -248,6 +256,7 @@ static int __get_cpu_architecture(void)
return cpu_arch;
}
+#endif
int __pure cpu_architecture(void)
{
@@ -375,6 +384,7 @@ static void __init feat_v6_fixup(void)
*/
void cpu_init(void)
{
+#ifndef CONFIG_CPU_V7M
unsigned int cpu = smp_processor_id();
struct stack *stk = &stacks[cpu];
@@ -419,6 +429,7 @@ void cpu_init(void)
"I" (offsetof(struct stack, und[0])),
PLC (PSR_F_BIT | PSR_I_BIT | SVC_MODE)
: "r14");
+#endif
}
int __cpu_logical_map[NR_CPUS];
diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c
index b0179b8..12d976b 100644
--- a/arch/arm/kernel/traps.c
+++ b/arch/arm/kernel/traps.c
@@ -819,6 +819,7 @@ static void __init kuser_get_tls_init(unsigned long vectors)
void __init early_trap_init(void *vectors_base)
{
+#ifndef CONFIG_CPU_V7M
unsigned long vectors = (unsigned long)vectors_base;
extern char __stubs_start[], __stubs_end[];
extern char __vectors_start[], __vectors_end[];
@@ -850,4 +851,5 @@ void __init early_trap_init(void *vectors_base)
flush_icache_range(vectors, vectors + PAGE_SIZE);
modify_domain(DOMAIN_USER, DOMAIN_CLIENT);
+#endif
}
diff --git a/arch/arm/mm/nommu.c b/arch/arm/mm/nommu.c
index d51225f..4bc8ae5 100644
--- a/arch/arm/mm/nommu.c
+++ b/arch/arm/mm/nommu.c
@@ -20,12 +20,14 @@
void __init arm_mm_memblock_reserve(void)
{
+#ifndef CONFIG_CPU_V7M
/*
* Register the exception vector page.
* some architectures which the DRAM is the exception vector to trap,
* alloc_page breaks with error, although it is not NULL, but "0."
*/
memblock_reserve(CONFIG_VECTORS_BASE, PAGE_SIZE);
+#endif
}
void __init sanity_check_meminfo(void)
diff --git a/arch/arm/mm/proc-v7m.S b/arch/arm/mm/proc-v7m.S
new file mode 100644
index 0000000..2b8eb97
--- /dev/null
+++ b/arch/arm/mm/proc-v7m.S
@@ -0,0 +1,161 @@
+/*
+ * linux/arch/arm/mm/proc-v7m.S
+ *
+ * Copyright (C) 2008 ARM Ltd.
+ * Copyright (C) 2001 Deep Blue Solutions Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This is the "shell" of the ARMv7-M processor support.
+ */
+#include <linux/linkage.h>
+#include <asm/assembler.h>
+
+ENTRY(cpu_v7m_proc_init)
+ mov pc, lr
+ENDPROC(cpu_v7m_proc_init)
+
+ENTRY(cpu_v7m_proc_fin)
+ mov pc, lr
+ENDPROC(cpu_v7m_proc_fin)
+
+/*
+ * cpu_v7m_reset(loc)
+ *
+ * Perform a soft reset of the system. Put the CPU into the
+ * same state as it would be if it had been reset, and branch
+ * to what would be the reset vector.
+ *
+ * - loc - location to jump to for soft reset
+ */
+ .align 5
+ENTRY(cpu_v7m_reset)
+ mov pc, r0
+ENDPROC(cpu_v7m_reset)
+
+/*
+ * cpu_v7m_do_idle()
+ *
+ * Idle the processor (eg, wait for interrupt).
+ *
+ * IRQs are already disabled.
+ */
+ENTRY(cpu_v7m_do_idle)
+ wfi
+ mov pc, lr
+ENDPROC(cpu_v7m_do_idle)
+
+ENTRY(cpu_v7m_dcache_clean_area)
+ mov pc, lr
+ENDPROC(cpu_v7m_dcache_clean_area)
+
+/*
+ * There is no MMU, so here is nothing to do.
+ */
+ENTRY(cpu_v7m_switch_mm)
+ mov pc, lr
+ENDPROC(cpu_v7m_switch_mm)
+
+cpu_v7m_name:
+ .ascii "ARMv7-M Processor"
+ .align
+
+ .section ".text.init", #alloc, #execinstr
+
+/*
+ * __v7m_setup
+ *
+ * This should be able to cover all ARMv7-M cores.
+ */
+__v7m_setup:
+ @ Configure the vector table base address
+ ldr r0, =0xe000ed08 @ vector table base address
+ ldr r12, =vector_table
+ str r12, [r0]
+
+ @ Lower the priority of the SVC and PendSV exceptions
+ ldr r0, =0xe000ed1c
+ mov r5, #0x80000000
+ str r5, [r0] @ set SVC priority
+ ldr r0, =0xe000ed20
+ mov r5, #0x00800000
+ str r5, [r0] @ set PendSV priority
+
+ @ SVC to run the kernel in this mode
+ adr r0, BSYM(1f)
+ ldr r5, [r12, #11 * 4] @ read the SVC vector entry
+ str r0, [r12, #11 * 4] @ write the temporary SVC vector entry
+ mov r6, lr @ save LR
+ mov r7, sp @ save SP
+ ldr sp, =__v7m_setup_stack_top
+ cpsie i
+ svc #0
+1: cpsid i
+ str r5, [r12, #11 * 4] @ restore the original SVC vector entry
+ mov lr, r6 @ restore LR
+ mov sp, r7 @ restore SP
+
+ @ Special-purpose control register
+ mov r0, #1
+ msr control, r0 @ Thread mode has unpriviledged access
+
+ @ Configure the System Control Register
+ ldr r0, =0xe000ed14 @ system control register
+ ldr r12, [r0]
+ orr r12, #1 << 9 @ STKALIGN
+ str r12, [r0]
+ mov pc, lr
+ENDPROC(__v7m_setup)
+
+ .align 2
+ .type v7m_processor_functions, #object
+ENTRY(v7m_processor_functions)
+ .word nommu_early_abort
+ .word cpu_v7m_proc_init
+ .word cpu_v7m_proc_fin
+ .word cpu_v7m_reset
+ .word cpu_v7m_do_idle
+ .word cpu_v7m_dcache_clean_area
+ .word cpu_v7m_switch_mm
+ .word 0 @ cpu_v7m_set_pte_ext
+ .word legacy_pabort
+ .size v7m_processor_functions, . - v7m_processor_functions
+
+ .type cpu_arch_name, #object
+cpu_arch_name:
+ .asciz "armv7m"
+ .size cpu_arch_name, . - cpu_arch_name
+
+ .type cpu_elf_name, #object
+cpu_elf_name:
+ .asciz "v7m"
+ .size cpu_elf_name, . - cpu_elf_name
+ .align
+
+ .section ".proc.info.init", #alloc, #execinstr
+
+ /*
+ * Match any ARMv7-M processor core.
+ */
+ .type __v7m_proc_info, #object
+__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
+ b __v7m_setup @ proc_info_list.__cpu_flush
+ .long cpu_arch_name
+ .long cpu_elf_name
+ .long HWCAP_SWP|HWCAP_HALF|HWCAP_THUMB|HWCAP_FAST_MULT|HWCAP_EDSP
+ .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 0 @ proc_info_list.cache
+ .size __v7m_proc_info, . - __v7m_proc_info
+
+__v7m_setup_stack:
+ .space 4 * 8 @ 8 registers
+__v7m_setup_stack_top:
--
1.7.10.4
^ permalink raw reply related [flat|nested] 11+ messages in thread* [PATCH v7 3/3] Cortex-M3: Add support for exception handling
2012-10-17 8:34 [PATCH v7 0/3] Yet another update for the Cortex-M3 series Uwe Kleine-König
2012-10-17 8:34 ` [PATCH v7 1/3] ARM: make cr_alignment read-only #ifndef CONFIG_CPU_CP15 Uwe Kleine-König
2012-10-17 8:34 ` [PATCH v7 2/3] Cortex-M3: Add base support for Cortex-M3 Uwe Kleine-König
@ 2012-10-17 8:34 ` Uwe Kleine-König
2013-01-11 11:05 ` Uwe Kleine-König
2013-01-11 9:47 ` [PATCH v7 0/3] Yet another update for the Cortex-M3 series Uwe Kleine-König
3 siblings, 1 reply; 11+ messages in thread
From: Uwe Kleine-König @ 2012-10-17 8:34 UTC (permalink / raw)
To: linux-arm-kernel
This patch implements the exception handling for the ARMv7-M
architecture (pretty different from the A or R profiles).
It bases on work done earlier by Catalin for 2.6.33 but was nearly
completely rewritten to use a pt_regs layout compatible to the A
profile.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Uwe Kleine-K?nig <u.kleine-koenig@pengutronix.de>
---
Changes since v6:
- not so trivially rebased on v3.7-rc1 because of Al Viro's kernel_execve
patches
arch/arm/kernel/entry-common.S | 4 ++
| 148 ++++++++++++++++++++++++++++++++++++++++
arch/arm/kernel/entry-v7m.S | 134 ++++++++++++++++++++++++++++++++++++
arch/arm/kernel/process.c | 4 ++
arch/arm/kernel/ptrace.c | 3 +
5 files changed, 293 insertions(+)
create mode 100644 arch/arm/kernel/entry-v7m.S
diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S
index 3471175..48d8dc0 100644
--- a/arch/arm/kernel/entry-common.S
+++ b/arch/arm/kernel/entry-common.S
@@ -339,6 +339,9 @@ ENDPROC(ftrace_stub)
.align 5
ENTRY(vector_swi)
+#ifdef CONFIG_CPU_V7M
+ v7m_exception_entry
+#else
sub sp, sp, #S_FRAME_SIZE
stmia sp, {r0 - r12} @ Calling r0 - r12
ARM( add r8, sp, #S_PC )
@@ -349,6 +352,7 @@ ENTRY(vector_swi)
str lr, [sp, #S_PC] @ Save calling PC
str r8, [sp, #S_PSR] @ Save CPSR
str r0, [sp, #S_OLD_R0] @ Save OLD_R0
+#endif
zero_fp
/*
--git a/arch/arm/kernel/entry-header.S b/arch/arm/kernel/entry-header.S
index 9a8531e..33d9900 100644
--- a/arch/arm/kernel/entry-header.S
+++ b/arch/arm/kernel/entry-header.S
@@ -44,6 +44,145 @@
#endif
.endm
+#ifdef CONFIG_CPU_V7M
+/*
+ * ARMv7-M exception entry/exit macros.
+ *
+ * xPSR, ReturnAddress(), LR (R14), R12, R3, R2, R1, and R0 are
+ * automatically saved on the current stack (32 words) before
+ * switching to the exception stack (SP_main).
+ *
+ * If exception is taken while in user mode, SP_main is
+ * empty. Otherwise, SP_main is aligned to 64 bit automatically
+ * (CCR.STKALIGN set).
+ *
+ * Linux assumes that the interrupts are disabled when entering an
+ * exception handler and it may BUG if this is not the case. Interrupts
+ * are disabled during entry and reenabled in the exit macro.
+ *
+ * v7m_exception_fast_exit is used when returning from interrupts.
+ *
+ * v7m_exception_slow_exit is used when returning from SVC or PendSV.
+ * When returning to kernel mode, we don't return from exception.
+ */
+ .macro v7m_exception_entry
+ @ determine the location of the registers saved by the core during
+ @ exception entry. Depending on the mode the cpu was in when the
+ @ exception happend that is either on the main or the process stack.
+ @ Bit 2 of EXC_RETURN stored in the lr register specifies which stack
+ @ was used.
+ tst lr, #0x4
+ mrsne r12, psp
+ moveq r12, sp
+
+ @ we cannot rely on r0-r3 and r12 matching the value saved in the
+ @ exception frame because of tail-chaining. So these have to be
+ @ reloaded.
+ ldmia r12!, {r0-r3}
+
+ @ Linux expects to have irqs off. Do it here before taking stack space
+ cpsid i
+
+ sub sp, #S_FRAME_SIZE-S_IP
+ stmdb sp!, {r0-r11}
+
+ @ load saved r12, lr, return address and xPSR.
+ @ r0-r7 are used for signals and never touched from now on. Clobbering
+ @ r8-r12 is OK.
+ mov r9, r12
+ ldmia r9!, {r8, r10-r12}
+
+ @ calculate the original stack pointer value.
+ @ r9 currently points to the memory location just above the auto saved
+ @ xPSR. If the FP extension is implemented and bit 4 of EXC_RETURN is 0
+ @ then space was allocated for FP state. That is space for 18 32-bit
+ @ values. (If FP extension is unimplemented, bit 4 is 1.)
+ @ Additionally the cpu might automatically 8-byte align the stack. Bit 9
+ @ of the saved xPSR specifies if stack aligning took place. In this case
+ @ another 32-bit value is included in the stack.
+
+ tst lr, #0x10
+ addeq r9, r9, #576
+
+ tst r12, 0x100
+ addne r9, r9, #4
+
+ @ store saved r12 using str to have a register to hold the base for stm
+ str r8, [sp, #S_IP]
+ add r8, sp, #S_SP
+ @ store r13-r15, xPSR
+ stmia r8!, {r9-r12}
+ @ store r0 once more and EXC_RETURN
+ stmia r8, {r0, lr}
+ .endm
+
+ .macro v7m_exception_fast_exit
+ @ registers r0-r3 and r12 are automatically restored on exception
+ @ return. r4-r7 were not clobbered in v7m_exception_entry so for
+ @ correctness they don't need to be restored. So only r8-r11 must be
+ @ restored here. The easiest way to do so is to restore r0-r7, too.
+ ldmia sp!, {r0-r11}
+ add sp, #S_FRAME_SIZE-S_IP
+ cpsie i
+ bx lr
+ .endm
+
+ .macro v7m_exception_slow_exit ret_r0
+ cpsid i
+ ldr lr, [sp, #S_EXC_RET] @ read exception LR
+ tst lr, #0x8
+ bne 1f @ go to thread mode using exception return
+
+ /*
+ * return to kernel thread
+ * sp is already set up (and might be unset in pt_regs), so only
+ * restore r0-r12 and pc
+ */
+ ldmia sp, {r0-r12}
+ ldr lr, [sp, #S_PC]
+ add sp, sp, #S_FRAME_SIZE
+ cpsie i
+ bx lr
+
+1: /*
+ * return to userspace
+ */
+
+ @ read original r12, sp, lr, pc and xPSR
+ add r12, sp, #S_IP
+ ldmia r12, {r1-r5}
+
+ @ handle stack aligning
+ tst r5, #0x100
+ subne r2, r2, #4
+
+ @ skip over stack space for fp saving
+ tst lr, #0x10
+ subeq r2, r2, #576
+
+ @ write basic exception frame
+ stmdb r2!, {r1, r3-r5}
+ ldmia sp, {r1, r3-r5}
+ .if \ret_r0
+ stmdb r2!, {r0, r3-r5}
+ .else
+ stmdb r2!, {r1, r3-r5}
+ .endif
+
+ @ restore process sp
+ msr psp, r2
+
+ @ restore original r4-r11
+ ldmia sp!, {r0-r11}
+
+ @ restore main sp
+ add sp, sp, #S_FRAME_SIZE-S_IP
+
+ cpsie i
+ bx lr
+ .endm
+#endif /* CONFIG_CPU_V7M */
+
@
@ Store/load the USER SP and LR registers by switching to the SYS
@ mode. Useful in Thumb-2 mode where "stm/ldm rd, {sp, lr}^" is not
@@ -131,6 +270,14 @@
rfeia sp!
.endm
+#ifdef CONFIG_CPU_V7M
+ .macro restore_user_regs, fast = 0, offset = 0
+ .if \offset
+ add sp, #\offset
+ .endif
+ v7m_exception_slow_exit ret_r0 = \fast
+ .endm
+#else /* !CONFIG_CPU_V7M */
.macro restore_user_regs, fast = 0, offset = 0
clrex @ clear the exclusive monitor
mov r2, sp
@@ -147,6 +294,7 @@
add sp, sp, #S_FRAME_SIZE - S_SP
movs pc, lr @ return & move spsr_svc into cpsr
.endm
+#endif /* CONFIG_CPU_V7M */
.macro get_thread_info, rd
mov \rd, sp
diff --git a/arch/arm/kernel/entry-v7m.S b/arch/arm/kernel/entry-v7m.S
new file mode 100644
index 0000000..a0991dc
--- /dev/null
+++ b/arch/arm/kernel/entry-v7m.S
@@ -0,0 +1,134 @@
+/*
+ * linux/arch/arm/kernel/entry-v7m.S
+ *
+ * Copyright (C) 2008 ARM Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * Low-level vector interface routines for the ARMv7-M architecture
+ */
+#include <asm/memory.h>
+#include <asm/glue.h>
+#include <asm/thread_notify.h>
+
+#include <mach/entry-macro.S>
+
+#include "entry-header.S"
+
+#ifdef CONFIG_PREEMPT
+#error "CONFIG_PREEMPT not supported on the current ARMv7M implementation"
+#endif
+#ifdef CONFIG_TRACE_IRQFLAGS
+#error "CONFIG_TRACE_IRQFLAGS not supported on the current ARMv7M implementation"
+#endif
+
+__invalid_entry:
+ v7m_exception_entry
+ adr r0, strerr
+ mrs r1, ipsr
+ mov r2, lr
+ bl printk
+ mov r0, sp
+ bl show_regs
+1: b 1b
+ENDPROC(__invalid_entry)
+
+strerr: .asciz "\nUnhandled exception: IPSR = %08lx LR = %08lx\n"
+
+ .align 2
+__irq_entry:
+ v7m_exception_entry
+
+ @
+ @ Invoke the IRQ handler
+ @
+ mrs r0, ipsr
+ and r0, #0xff
+ sub r0, #16 @ IRQ number
+ mov r1, sp
+ @ routine called with r0 = irq number, r1 = struct pt_regs *
+ bl asm_do_IRQ
+
+ @
+ @ Check for any pending work if returning to user
+ @
+ ldr lr, [sp, #S_EXC_RET]
+ tst lr, #0x8 @ check the return stack
+ beq 2f @ returning to handler mode
+ get_thread_info tsk
+ ldr r1, [tsk, #TI_FLAGS]
+ tst r1, #_TIF_WORK_MASK
+ beq 2f @ no work pending
+ ldr r1, =0xe000ed04 @ ICSR
+ mov r0, #1 << 28 @ ICSR.PENDSVSET
+ str r0, [r1] @ raise PendSV
+
+2:
+ v7m_exception_fast_exit
+ENDPROC(__irq_entry)
+
+__pendsv_entry:
+ v7m_exception_entry
+
+ ldr r1, =0xe000ed04 @ ICSR
+ mov r0, #1 << 27 @ ICSR.PENDSVCLR
+ str r0, [r1] @ clear PendSV
+
+ @ execute the pending work, including reschedule
+ get_thread_info tsk
+ mov why, #0
+ b ret_to_user
+ENDPROC(__pendsv_entry)
+
+/*
+ * Register switch for ARMv7-M processors.
+ * r0 = previous task_struct, r1 = previous thread_info, r2 = next thread_info
+ * previous and next are guaranteed not to be the same.
+ */
+ENTRY(__switch_to)
+ .fnstart
+ .cantunwind
+ add ip, r1, #TI_CPU_SAVE
+ stmia ip!, {r4 - r11} @ Store most regs on stack
+ str sp, [ip], #4
+ str lr, [ip], #4
+ mov r5, r0
+ add r4, r2, #TI_CPU_SAVE
+ ldr r0, =thread_notify_head
+ mov r1, #THREAD_NOTIFY_SWITCH
+ bl atomic_notifier_call_chain
+ mov ip, r4
+ mov r0, r5
+ ldmia ip!, {r4 - r11} @ Load all regs saved previously
+ ldr sp, [ip], #4
+ ldr pc, [ip]
+ .fnend
+ENDPROC(__switch_to)
+
+ .data
+ .align 8
+/*
+ * Vector table (64 words => 256 bytes natural alignment)
+ */
+ENTRY(vector_table)
+ .long 0 @ 0 - Reset stack pointer
+ .long __invalid_entry @ 1 - Reset
+ .long __invalid_entry @ 2 - NMI
+ .long __invalid_entry @ 3 - HardFault
+ .long __invalid_entry @ 4 - MemManage
+ .long __invalid_entry @ 5 - BusFault
+ .long __invalid_entry @ 6 - UsageFault
+ .long __invalid_entry @ 7 - Reserved
+ .long __invalid_entry @ 8 - Reserved
+ .long __invalid_entry @ 9 - Reserved
+ .long __invalid_entry @ 10 - Reserved
+ .long vector_swi @ 11 - SVCall
+ .long __invalid_entry @ 12 - Debug Monitor
+ .long __invalid_entry @ 13 - Reserved
+ .long __pendsv_entry @ 14 - PendSV
+ .long __invalid_entry @ 15 - SysTick
+ .rept 64 - 16
+ .long __irq_entry @ 16..64 - External Interrupts
+ .endr
diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c
index 90084a6..3d745d4 100644
--- a/arch/arm/kernel/process.c
+++ b/arch/arm/kernel/process.c
@@ -387,6 +387,10 @@ copy_thread(unsigned long clone_flags, unsigned long stack_start,
*childregs = *regs;
childregs->ARM_r0 = 0;
childregs->ARM_sp = stack_start;
+#if defined CONFIG_CPU_V7M
+ /* Return to Thread mode with Process stack */
+ childregs->ARM_EXC_RET = 0xfffffffdUL;
+#endif
} else {
memset(childregs, 0, sizeof(struct pt_regs));
thread->cpu_context.r4 = stk_sz;
diff --git a/arch/arm/kernel/ptrace.c b/arch/arm/kernel/ptrace.c
index 739db3a..55df1d5 100644
--- a/arch/arm/kernel/ptrace.c
+++ b/arch/arm/kernel/ptrace.c
@@ -87,6 +87,9 @@ static const struct pt_regs_offset regoffset_table[] = {
REG_OFFSET_NAME(pc),
REG_OFFSET_NAME(cpsr),
REG_OFFSET_NAME(ORIG_r0),
+#ifdef CONFIG_CPU_V7M
+ REG_OFFSET_NAME(EXC_RET),
+#endif
REG_OFFSET_END,
};
--
1.7.10.4
^ permalink raw reply related [flat|nested] 11+ messages in thread* [PATCH v7 3/3] Cortex-M3: Add support for exception handling
2012-10-17 8:34 ` [PATCH v7 3/3] Cortex-M3: Add support for exception handling Uwe Kleine-König
@ 2013-01-11 11:05 ` Uwe Kleine-König
2013-01-11 11:09 ` Russell King - ARM Linux
0 siblings, 1 reply; 11+ messages in thread
From: Uwe Kleine-König @ 2013-01-11 11:05 UTC (permalink / raw)
To: linux-arm-kernel
Hello,
On Wed, Oct 17, 2012 at 10:34:32AM +0200, Uwe Kleine-K?nig wrote:
> +/*
> + * Register switch for ARMv7-M processors.
> + * r0 = previous task_struct, r1 = previous thread_info, r2 = next thread_info
> + * previous and next are guaranteed not to be the same.
> + */
> +ENTRY(__switch_to)
> + .fnstart
> + .cantunwind
> + add ip, r1, #TI_CPU_SAVE
> + stmia ip!, {r4 - r11} @ Store most regs on stack
> + str sp, [ip], #4
> + str lr, [ip], #4
> + mov r5, r0
> + add r4, r2, #TI_CPU_SAVE
> + ldr r0, =thread_notify_head
> + mov r1, #THREAD_NOTIFY_SWITCH
> + bl atomic_notifier_call_chain
> + mov ip, r4
> + mov r0, r5
> + ldmia ip!, {r4 - r11} @ Load all regs saved previously
> + ldr sp, [ip], #4
> + ldr pc, [ip]
> + .fnend
> +ENDPROC(__switch_to)
this code triggers a warning
This instruction may be unpredictable if executed on M-profile
cores with interrupts enabled.
with newer toolchains (seen with gcc 4.7.2) because of errata 752419
(Interrupted loads to SP can cause erroneous behaviour) which badly
affects the following instructions:
ldr sp,[Rn],#imm
ldr sp,[Rn,#imm]!
I think it's not a problem here as irqs are off during task switching,
but when changing
ldr sp, [ip], #4
ldr pc, [ip]
to
ldr sp, [ip]
ldr pc, [ip, #4]!
the result is equivalent and gcc is happy.
I fixed that accordingly in my for-next branch.
Best regards
Uwe
--
Pengutronix e.K. | Uwe Kleine-K?nig |
Industrial Linux Solutions | http://www.pengutronix.de/ |
^ permalink raw reply [flat|nested] 11+ messages in thread* [PATCH v7 3/3] Cortex-M3: Add support for exception handling
2013-01-11 11:05 ` Uwe Kleine-König
@ 2013-01-11 11:09 ` Russell King - ARM Linux
2013-01-11 11:14 ` Uwe Kleine-König
0 siblings, 1 reply; 11+ messages in thread
From: Russell King - ARM Linux @ 2013-01-11 11:09 UTC (permalink / raw)
To: linux-arm-kernel
On Fri, Jan 11, 2013 at 12:05:44PM +0100, Uwe Kleine-K?nig wrote:
> Hello,
>
> On Wed, Oct 17, 2012 at 10:34:32AM +0200, Uwe Kleine-K?nig wrote:
> > +/*
> > + * Register switch for ARMv7-M processors.
> > + * r0 = previous task_struct, r1 = previous thread_info, r2 = next thread_info
> > + * previous and next are guaranteed not to be the same.
> > + */
> > +ENTRY(__switch_to)
> > + .fnstart
> > + .cantunwind
> > + add ip, r1, #TI_CPU_SAVE
> > + stmia ip!, {r4 - r11} @ Store most regs on stack
> > + str sp, [ip], #4
> > + str lr, [ip], #4
> > + mov r5, r0
> > + add r4, r2, #TI_CPU_SAVE
> > + ldr r0, =thread_notify_head
> > + mov r1, #THREAD_NOTIFY_SWITCH
> > + bl atomic_notifier_call_chain
> > + mov ip, r4
> > + mov r0, r5
> > + ldmia ip!, {r4 - r11} @ Load all regs saved previously
> > + ldr sp, [ip], #4
> > + ldr pc, [ip]
> > + .fnend
> > +ENDPROC(__switch_to)
> this code triggers a warning
>
> This instruction may be unpredictable if executed on M-profile
> cores with interrupts enabled.
>
> with newer toolchains (seen with gcc 4.7.2) because of errata 752419
> (Interrupted loads to SP can cause erroneous behaviour) which badly
> affects the following instructions:
>
> ldr sp,[Rn],#imm
> ldr sp,[Rn,#imm]!
Wonder if that means we need to fix it in entry-armv.S too, as it uses
the same sequence for Thumb:
THUMB( ldr sp, [ip], #4 )
THUMB( ldr pc, [ip] )
and, of course, M-profile stuff is also Thumb.
^ permalink raw reply [flat|nested] 11+ messages in thread* [PATCH v7 3/3] Cortex-M3: Add support for exception handling
2013-01-11 11:09 ` Russell King - ARM Linux
@ 2013-01-11 11:14 ` Uwe Kleine-König
2013-01-11 11:26 ` Uwe Kleine-König
0 siblings, 1 reply; 11+ messages in thread
From: Uwe Kleine-König @ 2013-01-11 11:14 UTC (permalink / raw)
To: linux-arm-kernel
Hello Russell,
On Fri, Jan 11, 2013 at 11:09:26AM +0000, Russell King - ARM Linux wrote:
> On Fri, Jan 11, 2013 at 12:05:44PM +0100, Uwe Kleine-K?nig wrote:
> > Hello,
> >
> > On Wed, Oct 17, 2012 at 10:34:32AM +0200, Uwe Kleine-K?nig wrote:
> > > +/*
> > > + * Register switch for ARMv7-M processors.
> > > + * r0 = previous task_struct, r1 = previous thread_info, r2 = next thread_info
> > > + * previous and next are guaranteed not to be the same.
> > > + */
> > > +ENTRY(__switch_to)
> > > + .fnstart
> > > + .cantunwind
> > > + add ip, r1, #TI_CPU_SAVE
> > > + stmia ip!, {r4 - r11} @ Store most regs on stack
> > > + str sp, [ip], #4
> > > + str lr, [ip], #4
> > > + mov r5, r0
> > > + add r4, r2, #TI_CPU_SAVE
> > > + ldr r0, =thread_notify_head
> > > + mov r1, #THREAD_NOTIFY_SWITCH
> > > + bl atomic_notifier_call_chain
> > > + mov ip, r4
> > > + mov r0, r5
> > > + ldmia ip!, {r4 - r11} @ Load all regs saved previously
> > > + ldr sp, [ip], #4
> > > + ldr pc, [ip]
> > > + .fnend
> > > +ENDPROC(__switch_to)
> > this code triggers a warning
> >
> > This instruction may be unpredictable if executed on M-profile
> > cores with interrupts enabled.
> >
> > with newer toolchains (seen with gcc 4.7.2) because of errata 752419
> > (Interrupted loads to SP can cause erroneous behaviour) which badly
> > affects the following instructions:
> >
> > ldr sp,[Rn],#imm
> > ldr sp,[Rn,#imm]!
>
> Wonder if that means we need to fix it in entry-armv.S too, as it uses
> the same sequence for Thumb:
>
> THUMB( ldr sp, [ip], #4 )
> THUMB( ldr pc, [ip] )
>
> and, of course, M-profile stuff is also Thumb.
entry-armv.S is not affected as this code snipplet is for switching from
ARM to THUMB mode on kernel entry. The M-profile CPUs don't have a ARM
mode, so this code isn't active for them anyhow. (I have a patch in my
queue to allow entry in Thumb mode for thumb-only CPUs.)
Best regards and thanks for your heedfulness,
Uwe
--
Pengutronix e.K. | Uwe Kleine-K?nig |
Industrial Linux Solutions | http://www.pengutronix.de/ |
^ permalink raw reply [flat|nested] 11+ messages in thread* [PATCH v7 3/3] Cortex-M3: Add support for exception handling
2013-01-11 11:14 ` Uwe Kleine-König
@ 2013-01-11 11:26 ` Uwe Kleine-König
0 siblings, 0 replies; 11+ messages in thread
From: Uwe Kleine-König @ 2013-01-11 11:26 UTC (permalink / raw)
To: linux-arm-kernel
Hello Russell,
On Fri, Jan 11, 2013 at 12:14:56PM +0100, Uwe Kleine-K?nig wrote:
> On Fri, Jan 11, 2013 at 11:09:26AM +0000, Russell King - ARM Linux wrote:
> > On Fri, Jan 11, 2013 at 12:05:44PM +0100, Uwe Kleine-K?nig wrote:
> > > Hello,
> > >
> > > On Wed, Oct 17, 2012 at 10:34:32AM +0200, Uwe Kleine-K?nig wrote:
> > > > +/*
> > > > + * Register switch for ARMv7-M processors.
> > > > + * r0 = previous task_struct, r1 = previous thread_info, r2 = next thread_info
> > > > + * previous and next are guaranteed not to be the same.
> > > > + */
> > > > +ENTRY(__switch_to)
> > > > + .fnstart
> > > > + .cantunwind
> > > > + add ip, r1, #TI_CPU_SAVE
> > > > + stmia ip!, {r4 - r11} @ Store most regs on stack
> > > > + str sp, [ip], #4
> > > > + str lr, [ip], #4
> > > > + mov r5, r0
> > > > + add r4, r2, #TI_CPU_SAVE
> > > > + ldr r0, =thread_notify_head
> > > > + mov r1, #THREAD_NOTIFY_SWITCH
> > > > + bl atomic_notifier_call_chain
> > > > + mov ip, r4
> > > > + mov r0, r5
> > > > + ldmia ip!, {r4 - r11} @ Load all regs saved previously
> > > > + ldr sp, [ip], #4
> > > > + ldr pc, [ip]
> > > > + .fnend
> > > > +ENDPROC(__switch_to)
> > > this code triggers a warning
> > >
> > > This instruction may be unpredictable if executed on M-profile
> > > cores with interrupts enabled.
> > >
> > > with newer toolchains (seen with gcc 4.7.2) because of errata 752419
> > > (Interrupted loads to SP can cause erroneous behaviour) which badly
> > > affects the following instructions:
> > >
> > > ldr sp,[Rn],#imm
> > > ldr sp,[Rn,#imm]!
> >
> > Wonder if that means we need to fix it in entry-armv.S too, as it uses
> > the same sequence for Thumb:
> >
> > THUMB( ldr sp, [ip], #4 )
> > THUMB( ldr pc, [ip] )
> >
> > and, of course, M-profile stuff is also Thumb.
> entry-armv.S is not affected as this code snipplet is for switching from
> ARM to THUMB mode on kernel entry. The M-profile CPUs don't have a ARM
> mode, so this code isn't active for them anyhow. (I have a patch in my
> queue to allow entry in Thumb mode for thumb-only CPUs.)
This is wrong, it's not in initial switching to Thumb mode but in
__switch_to. Still this code isn't used for Cortex-M3 CPUs.
Best regards
Uwe
--
Pengutronix e.K. | Uwe Kleine-K?nig |
Industrial Linux Solutions | http://www.pengutronix.de/ |
^ permalink raw reply [flat|nested] 11+ messages in thread
* [PATCH v7 0/3] Yet another update for the Cortex-M3 series
2012-10-17 8:34 [PATCH v7 0/3] Yet another update for the Cortex-M3 series Uwe Kleine-König
` (2 preceding siblings ...)
2012-10-17 8:34 ` [PATCH v7 3/3] Cortex-M3: Add support for exception handling Uwe Kleine-König
@ 2013-01-11 9:47 ` Uwe Kleine-König
3 siblings, 0 replies; 11+ messages in thread
From: Uwe Kleine-König @ 2013-01-11 9:47 UTC (permalink / raw)
To: linux-arm-kernel
Hello Russell,
On Wed, Oct 17, 2012 at 10:34:29AM +0200, Uwe Kleine-K?nig wrote:
> the only change since v6 is a rebase on top of v3.7-rc1 and so on Al
> Viro's changes to kernel_execve().
>
> These patches merge just fine into today's next and I put them into my
> branch that Stephen will pick for the next next.
>
> As before this doesn't make a functional M3 port as there are still some
> missing items. If you want to see the code live I also updated the efm32
> branch in my repository to be based on these patches. This code works,
> but isn't suitable for mainline yet. You can run it on EnergyMicro's
> efm32 devboard.
>
> Best regards
> Uwe
>
> Catalin Marinas (1):
> Cortex-M3: Add base support for Cortex-M3
>
> Uwe Kleine-K?nig (2):
> ARM: make cr_alignment read-only #ifndef CONFIG_CPU_CP15
> Cortex-M3: Add support for exception handling
These patches are in next since next-20121018 without any reported
problems. What do you think about inclusion for 3.9-rc1?
They are based on 3.7-rc1 and I'm currently porting my tree to 3.8-rc3
to test there.
Best regards
Uwe
--
Pengutronix e.K. | Uwe Kleine-K?nig |
Industrial Linux Solutions | http://www.pengutronix.de/ |
^ permalink raw reply [flat|nested] 11+ messages in thread