[1/2] xen/arm32: implement VFP context switch

Message ID 1369924733-18701-2-git-send-email-julien.grall@linaro.org
State Superseded
Headers show

Commit Message

Julien Grall May 30, 2013, 2:38 p.m.
Add support for VFP context switch on arm32 and a dummy support for arm64

Signed-off-by: Julien Grall <julien.grall@linaro.org>
---
 xen/arch/arm/arm32/Makefile     |    1 +
 xen/arch/arm/arm32/vfp.c        |   71 +++++++++++++++++++++++++++++++++++++++
 xen/arch/arm/arm64/Makefile     |    1 +
 xen/arch/arm/arm64/vfp.c        |   13 +++++++
 xen/arch/arm/domain.c           |    7 ++--
 xen/include/asm-arm/arm32/vfp.h |   29 ++++++++++++++++
 xen/include/asm-arm/arm64/vfp.h |   16 +++++++++
 xen/include/asm-arm/cpregs.h    |    7 ++++
 xen/include/asm-arm/domain.h    |    5 +++
 xen/include/asm-arm/vfp.h       |   10 ++++++
 10 files changed, 158 insertions(+), 2 deletions(-)
 create mode 100644 xen/arch/arm/arm32/vfp.c
 create mode 100644 xen/arch/arm/arm64/vfp.c
 create mode 100644 xen/include/asm-arm/arm32/vfp.h
 create mode 100644 xen/include/asm-arm/arm64/vfp.h

Comments

Ian Campbell May 30, 2013, 3:11 p.m. | #1
On Thu, 2013-05-30 at 15:38 +0100, Julien Grall wrote:
> diff --git a/xen/arch/arm/arm32/vfp.c b/xen/arch/arm/arm32/vfp.c
> new file mode 100644
> index 0000000..16f635a
> --- /dev/null
> +++ b/xen/arch/arm/arm32/vfp.c
> @@ -0,0 +1,71 @@
> +#include <xen/sched.h>
> +#include <asm/processor.h>
> +#include <asm/vfp.h>
> +
> +void vfp_save_state(struct vcpu *v)
> +{
[...]
> +}
> +
> +void vfp_restore_state(struct vcpu *v)
> +{
[...]

Without having read the documentation this seem plausible enough.

> +}
> +
> +/*
> + * Local variables:
> + * mode: C
> + * c-file-style: "BSD"
> + * c-basic-offset: 4
> + * indent-tabs-mode: nil
> + * End:
> + */
> diff --git a/xen/include/asm-arm/arm64/vfp.h b/xen/include/asm-arm/arm64/vfp.h
> new file mode 100644
> index 0000000..34cd202
> --- /dev/null
> +++ b/xen/include/asm-arm/arm64/vfp.h
> @@ -0,0 +1,16 @@
> +#ifndef _ARM_ARM64_VFP_H
> +#define _ARM_ARM32_VFP_H

Mismatch.

> +
> +struct vfp_state
> +{
> +};
> +
> +#endif /* _ARM_ARM32_VFP_H */

And again.

> +/*
> + * Local variables:
> + * mode: C
> + * c-file-style: "BSD"
> + * c-basic-offset: 4
> + * indent-tabs-mode: nil
> + * End:
> + */
> diff --git a/xen/include/asm-arm/cpregs.h b/xen/include/asm-arm/cpregs.h
> index f08d59a..d99ccfd 100644
> --- a/xen/include/asm-arm/cpregs.h
> +++ b/xen/include/asm-arm/cpregs.h
> @@ -60,6 +60,12 @@
>   * arguments, which are cp,opc1,crn,crm,opc2.
>   */
>  

+ /* Coprocessor 10 */

Please.

> +#define FPSCR           p10,7,c1,c0,0   /* Floating-Point Status and Control Register */
> +#define MVFR0           p10,7,c7,c0,0   /* Media and VFP Feature Register 0 */
> +#define FPEXC           p10,7,c8,c0,0   /* Floating-Point Exception Control Register */
> +#define FPINST          p10,7,c9,c0,0   /* Floating-Point Instruction Register */
> +#define FPINST2         p10,7,c10,c0,0  /* Floating-point Instruction Register 2 */
> +
>  /* Coprocessor 14 */
>  
>  /* CP14 CR0: */
> @@ -106,6 +112,7 @@
>  #define NSACR           p15,0,c1,c1,2   /* Non-Secure Access Control Register */
>  #define HSCTLR          p15,4,c1,c0,0   /* Hyp. System Control Register */
>  #define HCR             p15,4,c1,c1,0   /* Hyp. Configuration Register */
> +#define HCPTR           p15,4,c1,c1,2   /* Hyp. Coprocessor Trap Register */
>  
>  /* CP15 CR2: Translation Table Base and Control Registers */
>  #define TTBCR           p15,0,c2,c0,2   /* Translatation Table Base Control Register */
> diff --git a/xen/include/asm-arm/domain.h b/xen/include/asm-arm/domain.h
> index cb251cc..6b52b5e 100644
> --- a/xen/include/asm-arm/domain.h
> +++ b/xen/include/asm-arm/domain.h
> @@ -1,11 +1,13 @@
>  #ifndef __ASM_DOMAIN_H__
>  #define __ASM_DOMAIN_H__
>  
> +#include <asm/atomic.h>

What is this used for?

>  #include <xen/config.h>
>  #include <xen/cache.h>
>  #include <xen/sched.h>
>  #include <asm/page.h>
>  #include <asm/p2m.h>
> +#include <asm/vfp.h>
>  #include <public/hvm/params.h>
>  
>  /* Represents state corresponding to a block of 32 interrupts */
> diff --git a/xen/include/asm-arm/vfp.h b/xen/include/asm-arm/vfp.h
> index b800816..6ba3cd1 100644
> --- a/xen/include/asm-arm/vfp.h
> +++ b/xen/include/asm-arm/vfp.h
> @@ -2,7 +2,14 @@
>  #define __ARM_VFP_H_
>  
>  #include <xen/types.h>
> +#include <xen/sched.h>

> +#if defined(CONFIG_ARM_32)
> +# include <asm/arm32/vfp.h>
> +#elif defined(CONFIG_ARM_64)
> +# include <asm/arm64/vfp.h>

Did you mean to include a #else here?

> +# error "Unknown ARM variant"
> +#endif
>  
>  #ifdef CONFIG_ARM_32

I suppose the content of this #if now belongs in the subarch header.

>  
> @@ -32,6 +39,9 @@ static inline void enable_vfp(void)
>  }
>  #endif
>  
> +void vfp_save_state(struct vcpu *v);
> +void vfp_restore_state(struct vcpu *v);
> +
>  #endif
>  /*
>   * Local variables:
Julien Grall May 30, 2013, 3:25 p.m. | #2
On 05/30/2013 04:11 PM, Ian Campbell wrote:

> On Thu, 2013-05-30 at 15:38 +0100, Julien Grall wrote:
>> diff --git a/xen/arch/arm/arm32/vfp.c b/xen/arch/arm/arm32/vfp.c
>> new file mode 100644
>> index 0000000..16f635a
>> --- /dev/null
>> +++ b/xen/arch/arm/arm32/vfp.c
>> @@ -0,0 +1,71 @@
>> +#include <xen/sched.h>
>> +#include <asm/processor.h>
>> +#include <asm/vfp.h>
>> +
>> +void vfp_save_state(struct vcpu *v)
>> +{
> [...]
>> +}
>> +
>> +void vfp_restore_state(struct vcpu *v)
>> +{
> [...]
> 
> Without having read the documentation this seem plausible enough.
> 
>> +}
>> +
>> +/*
>> + * Local variables:
>> + * mode: C
>> + * c-file-style: "BSD"
>> + * c-basic-offset: 4
>> + * indent-tabs-mode: nil
>> + * End:
>> + */
>> diff --git a/xen/include/asm-arm/arm64/vfp.h b/xen/include/asm-arm/arm64/vfp.h
>> new file mode 100644
>> index 0000000..34cd202
>> --- /dev/null
>> +++ b/xen/include/asm-arm/arm64/vfp.h
>> @@ -0,0 +1,16 @@
>> +#ifndef _ARM_ARM64_VFP_H
>> +#define _ARM_ARM32_VFP_H
> 
> Mismatch.
> 
>> +
>> +struct vfp_state
>> +{
>> +};
>> +
>> +#endif /* _ARM_ARM32_VFP_H */
> 
> And again.
> 
>> +/*
>> + * Local variables:
>> + * mode: C
>> + * c-file-style: "BSD"
>> + * c-basic-offset: 4
>> + * indent-tabs-mode: nil
>> + * End:
>> + */
>> diff --git a/xen/include/asm-arm/cpregs.h b/xen/include/asm-arm/cpregs.h
>> index f08d59a..d99ccfd 100644
>> --- a/xen/include/asm-arm/cpregs.h
>> +++ b/xen/include/asm-arm/cpregs.h
>> @@ -60,6 +60,12 @@
>>   * arguments, which are cp,opc1,crn,crm,opc2.
>>   */
>>  
> 
> + /* Coprocessor 10 */
> 
> Please.
> 
>> +#define FPSCR           p10,7,c1,c0,0   /* Floating-Point Status and Control Register */
>> +#define MVFR0           p10,7,c7,c0,0   /* Media and VFP Feature Register 0 */
>> +#define FPEXC           p10,7,c8,c0,0   /* Floating-Point Exception Control Register */
>> +#define FPINST          p10,7,c9,c0,0   /* Floating-Point Instruction Register */
>> +#define FPINST2         p10,7,c10,c0,0  /* Floating-point Instruction Register 2 */
>> +
>>  /* Coprocessor 14 */
>>  
>>  /* CP14 CR0: */
>> @@ -106,6 +112,7 @@
>>  #define NSACR           p15,0,c1,c1,2   /* Non-Secure Access Control Register */
>>  #define HSCTLR          p15,4,c1,c0,0   /* Hyp. System Control Register */
>>  #define HCR             p15,4,c1,c1,0   /* Hyp. Configuration Register */
>> +#define HCPTR           p15,4,c1,c1,2   /* Hyp. Coprocessor Trap Register */
>>  
>>  /* CP15 CR2: Translation Table Base and Control Registers */
>>  #define TTBCR           p15,0,c2,c0,2   /* Translatation Table Base Control Register */
>> diff --git a/xen/include/asm-arm/domain.h b/xen/include/asm-arm/domain.h
>> index cb251cc..6b52b5e 100644
>> --- a/xen/include/asm-arm/domain.h
>> +++ b/xen/include/asm-arm/domain.h
>> @@ -1,11 +1,13 @@
>>  #ifndef __ASM_DOMAIN_H__
>>  #define __ASM_DOMAIN_H__
>>  
>> +#include <asm/atomic.h>
> 
> What is this used for?

Lost line. I will remove it.

> 
>>  #include <xen/config.h>
>>  #include <xen/cache.h>
>>  #include <xen/sched.h>
>>  #include <asm/page.h>
>>  #include <asm/p2m.h>
>> +#include <asm/vfp.h>
>>  #include <public/hvm/params.h>
>>  
>>  /* Represents state corresponding to a block of 32 interrupts */
>> diff --git a/xen/include/asm-arm/vfp.h b/xen/include/asm-arm/vfp.h
>> index b800816..6ba3cd1 100644
>> --- a/xen/include/asm-arm/vfp.h
>> +++ b/xen/include/asm-arm/vfp.h
>> @@ -2,7 +2,14 @@
>>  #define __ARM_VFP_H_
>>  
>>  #include <xen/types.h>
>> +#include <xen/sched.h>
> 
>> +#if defined(CONFIG_ARM_32)
>> +# include <asm/arm32/vfp.h>
>> +#elif defined(CONFIG_ARM_64)
>> +# include <asm/arm64/vfp.h>
> 
> Did you mean to include a #else here?


Yes. It was lost during the creation of the patch. I will pay more
attention in the next patch series.

> 
>> +# error "Unknown ARM variant"
>> +#endif
>>  
>>  #ifdef CONFIG_ARM_32
> 
> I suppose the content of this #if now belongs in the subarch header.

This part is removed in the next patch. I was thinking to invert the 2
patch as the second patch doesn't need the first one (except for the diff).

> 
>>  
>> @@ -32,6 +39,9 @@ static inline void enable_vfp(void)
>>  }
>>  #endif
>>  
>> +void vfp_save_state(struct vcpu *v);
>> +void vfp_restore_state(struct vcpu *v);
>> +
>>  #endif
>>  /*
>>   * Local variables:
> 
>

Patch

diff --git a/xen/arch/arm/arm32/Makefile b/xen/arch/arm/arm32/Makefile
index aaf277a..b903803 100644
--- a/xen/arch/arm/arm32/Makefile
+++ b/xen/arch/arm/arm32/Makefile
@@ -6,5 +6,6 @@  obj-y += proc-ca15.o
 
 obj-y += traps.o
 obj-y += domain.o
+obj-y += vfp.o
 
 obj-$(EARLY_PRINTK) += debug.o
diff --git a/xen/arch/arm/arm32/vfp.c b/xen/arch/arm/arm32/vfp.c
new file mode 100644
index 0000000..16f635a
--- /dev/null
+++ b/xen/arch/arm/arm32/vfp.c
@@ -0,0 +1,71 @@ 
+#include <xen/sched.h>
+#include <asm/processor.h>
+#include <asm/vfp.h>
+
+void vfp_save_state(struct vcpu *v)
+{
+    uint32_t tmp;
+
+    v->arch.vfp.fpexc = READ_CP32(FPEXC);
+
+    WRITE_CP32(v->arch.vfp.fpexc | FPEXC_EN, FPEXC);
+
+    v->arch.vfp.fpscr = READ_CP32(FPSCR);
+
+    if ( v->arch.vfp.fpexc & FPEXC_EX ) /* Check for sub-architecture */
+    {
+        v->arch.vfp.fpinst = READ_CP32(FPINST);
+
+        if ( v->arch.vfp.fpexc & FPEXC_FP2V )
+            v->arch.vfp.fpinst2 = READ_CP32(FPINST2);
+        /* Disable FPEXC_EX */
+        WRITE_CP32((v->arch.vfp.fpexc | FPEXC_EN) & ~FPEXC_EX, FPEXC);
+    }
+
+    /* Save {d0-d15} */
+    asm volatile("stc p11, cr0, [%0], #32*4" : : "r" (v->arch.vfp.fpregs1));
+
+    tmp = READ_CP32(MVFR0);
+    if ( (tmp & MVFR0_A_SIMD_MASK) == 2 ) /* 32 x 64 bits registers */
+    {
+        /* Save {d16-d31} */
+        asm volatile("stcl p11, cr0, [%0], #32*4" : : "r" (v->arch.vfp.fpregs2));
+    }
+
+    WRITE_CP32(v->arch.vfp.fpexc & ~(FPEXC_EN), FPEXC);
+}
+
+void vfp_restore_state(struct vcpu *v)
+{
+    uint32_t tmp = READ_CP32(FPEXC);
+
+    WRITE_CP32(tmp | FPEXC_EN, FPEXC);
+
+    /* Restore {d0-d15} */
+    asm volatile("ldc p11, cr0, [%0], #32*4" : : "r" (v->arch.vfp.fpregs1));
+
+    tmp = READ_CP32(MVFR0);
+    if ( (tmp & MVFR0_A_SIMD_MASK) == 2 ) /* 32 x 64 bits registers */
+        /* Restore {d16-d31} */
+        asm volatile("ldcl p11, cr0, [%0], #32*4" : : "r" (v->arch.vfp.fpregs2));
+
+    if ( v->arch.vfp.fpexc & FPEXC_EX )
+    {
+        WRITE_CP32(v->arch.vfp.fpinst, FPINST);
+        if ( v->arch.vfp.fpexc & FPEXC_FP2V )
+            WRITE_CP32(v->arch.vfp.fpinst2, FPINST2);
+    }
+
+    WRITE_CP32(v->arch.vfp.fpscr, FPSCR);
+
+    WRITE_CP32(v->arch.vfp.fpexc, FPEXC);
+}
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
diff --git a/xen/arch/arm/arm64/Makefile b/xen/arch/arm/arm64/Makefile
index 9484548..e06a0a9 100644
--- a/xen/arch/arm/arm64/Makefile
+++ b/xen/arch/arm/arm64/Makefile
@@ -5,5 +5,6 @@  obj-y += mode_switch.o
 
 obj-y += traps.o
 obj-y += domain.o
+obj-y += vfp.o
 
 obj-$(EARLY_PRINTK) += debug.o
diff --git a/xen/arch/arm/arm64/vfp.c b/xen/arch/arm/arm64/vfp.c
new file mode 100644
index 0000000..74e6a50
--- /dev/null
+++ b/xen/arch/arm/arm64/vfp.c
@@ -0,0 +1,13 @@ 
+#include <xen/sched.h>
+#include <asm/processor.h>
+#include <asm/vfp.h>
+
+void vfp_save_state(struct vcpu *v)
+{
+    /* TODO: implement it */
+}
+
+void vfp_restore_state(struct vcpu *v)
+{
+    /* TODO: implement it */
+}
diff --git a/xen/arch/arm/domain.c b/xen/arch/arm/domain.c
index 4c434a1..f465ab7 100644
--- a/xen/arch/arm/domain.c
+++ b/xen/arch/arm/domain.c
@@ -27,6 +27,7 @@ 
 #include <asm/p2m.h>
 #include <asm/irq.h>
 #include <asm/cpufeature.h>
+#include <asm/vfp.h>
 
 #include <asm/gic.h>
 #include "vtimer.h"
@@ -117,7 +118,8 @@  static void ctxt_switch_from(struct vcpu *p)
 
     /* XXX MPU */
 
-    /* XXX VFP */
+    /* VFP */
+    vfp_save_state(p);
 
     /* VGIC */
     gic_save_state(p);
@@ -143,7 +145,8 @@  static void ctxt_switch_to(struct vcpu *n)
     /* VGIC */
     gic_restore_state(n);
 
-    /* XXX VFP */
+    /* VFP */
+    vfp_restore_state(n);
 
     /* XXX MPU */
 
diff --git a/xen/include/asm-arm/arm32/vfp.h b/xen/include/asm-arm/arm32/vfp.h
new file mode 100644
index 0000000..c32296e
--- /dev/null
+++ b/xen/include/asm-arm/arm32/vfp.h
@@ -0,0 +1,29 @@ 
+#ifndef _ARM_ARM32_VFP_H
+#define _ARM_ARM32_VFP_H
+
+#define FPEXC_EX                (1u << 31)
+#define FPEXC_EN                (1u << 30)
+#define FPEXC_FP2V              (1u << 28)
+
+#define MVFR0_A_SIMD_MASK       (0xf << 0)
+
+struct vfp_state
+{
+    uint64_t fpregs1[16]; /* {d0-d15} */
+    uint64_t fpregs2[16]; /* {d16-d31} */
+    uint32_t fpexc;
+    uint32_t fpscr;
+    /* VFP implementation specific state */
+    uint32_t fpinst;
+    uint32_t fpinst2;
+};
+
+#endif /* _ARM_ARM32_VFP_H */
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
diff --git a/xen/include/asm-arm/arm64/vfp.h b/xen/include/asm-arm/arm64/vfp.h
new file mode 100644
index 0000000..34cd202
--- /dev/null
+++ b/xen/include/asm-arm/arm64/vfp.h
@@ -0,0 +1,16 @@ 
+#ifndef _ARM_ARM64_VFP_H
+#define _ARM_ARM32_VFP_H
+
+struct vfp_state
+{
+};
+
+#endif /* _ARM_ARM32_VFP_H */
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
diff --git a/xen/include/asm-arm/cpregs.h b/xen/include/asm-arm/cpregs.h
index f08d59a..d99ccfd 100644
--- a/xen/include/asm-arm/cpregs.h
+++ b/xen/include/asm-arm/cpregs.h
@@ -60,6 +60,12 @@ 
  * arguments, which are cp,opc1,crn,crm,opc2.
  */
 
+#define FPSCR           p10,7,c1,c0,0   /* Floating-Point Status and Control Register */
+#define MVFR0           p10,7,c7,c0,0   /* Media and VFP Feature Register 0 */
+#define FPEXC           p10,7,c8,c0,0   /* Floating-Point Exception Control Register */
+#define FPINST          p10,7,c9,c0,0   /* Floating-Point Instruction Register */
+#define FPINST2         p10,7,c10,c0,0  /* Floating-point Instruction Register 2 */
+
 /* Coprocessor 14 */
 
 /* CP14 CR0: */
@@ -106,6 +112,7 @@ 
 #define NSACR           p15,0,c1,c1,2   /* Non-Secure Access Control Register */
 #define HSCTLR          p15,4,c1,c0,0   /* Hyp. System Control Register */
 #define HCR             p15,4,c1,c1,0   /* Hyp. Configuration Register */
+#define HCPTR           p15,4,c1,c1,2   /* Hyp. Coprocessor Trap Register */
 
 /* CP15 CR2: Translation Table Base and Control Registers */
 #define TTBCR           p15,0,c2,c0,2   /* Translatation Table Base Control Register */
diff --git a/xen/include/asm-arm/domain.h b/xen/include/asm-arm/domain.h
index cb251cc..6b52b5e 100644
--- a/xen/include/asm-arm/domain.h
+++ b/xen/include/asm-arm/domain.h
@@ -1,11 +1,13 @@ 
 #ifndef __ASM_DOMAIN_H__
 #define __ASM_DOMAIN_H__
 
+#include <asm/atomic.h>
 #include <xen/config.h>
 #include <xen/cache.h>
 #include <xen/sched.h>
 #include <asm/page.h>
 #include <asm/p2m.h>
+#include <asm/vfp.h>
 #include <public/hvm/params.h>
 
 /* Represents state corresponding to a block of 32 interrupts */
@@ -188,6 +190,9 @@  struct arch_vcpu
     uint32_t joscr, jmcr;
 #endif
 
+    /* Float-pointer */
+    struct vfp_state vfp;
+
     /* CP 15 */
     uint32_t csselr;
 
diff --git a/xen/include/asm-arm/vfp.h b/xen/include/asm-arm/vfp.h
index b800816..6ba3cd1 100644
--- a/xen/include/asm-arm/vfp.h
+++ b/xen/include/asm-arm/vfp.h
@@ -2,7 +2,14 @@ 
 #define __ARM_VFP_H_
 
 #include <xen/types.h>
+#include <xen/sched.h>
 
+#if defined(CONFIG_ARM_32)
+# include <asm/arm32/vfp.h>
+#elif defined(CONFIG_ARM_64)
+# include <asm/arm64/vfp.h>
+# error "Unknown ARM variant"
+#endif
 
 #ifdef CONFIG_ARM_32
 
@@ -32,6 +39,9 @@  static inline void enable_vfp(void)
 }
 #endif
 
+void vfp_save_state(struct vcpu *v);
+void vfp_restore_state(struct vcpu *v);
+
 #endif
 /*
  * Local variables: