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Re: [Minios-devel] [UNIKRAFT PATCHv5 18/46] plat/kvm: Add Arm64 basic entry code



Hi Julien,

> -----Original Message-----
> From: Julien Grall <julien.grall@xxxxxxx>
> Sent: 2018年9月7日 22:58
> To: Wei Chen (Arm Technology China) <Wei.Chen@xxxxxxx>; minios-
> devel@xxxxxxxxxxxxxxxxxxxx; simon.kuenzer@xxxxxxxxx
> Cc: Kaly Xin (Arm Technology China) <Kaly.Xin@xxxxxxx>; nd <nd@xxxxxxx>
> Subject: Re: [Minios-devel] [UNIKRAFT PATCHv5 18/46] plat/kvm: Add Arm64 basic
> entry code
> 
> Hi,
> 
> On 08/10/2018 08:08 AM, Wei Chen wrote:
> > From: Wei Chen <Wei.Chen@xxxxxxx>
> >
> > QEMU/KVM can boot an Arm64 elf image without multiboot. In this case,
> > we can plage _libkvmplat_entry to entry64.S directly as the vCPU
> > reset entry. In this basic entry code, we just initialize the boot
> > stack and prepare jumping to _libkvmplat_start.
> >
> > Signed-off-by: Wei Chen <Wei.Chen@xxxxxxx>
> > ---
> >   arch/arm/Compiler.uk                |  4 ++
> >   arch/arm/Makefile.uk                |  4 ++
> >   plat/common/include/arm/arm64/asm.h | 77 +++++++++++++++++++++++++++++
> >   plat/common/include/arm/asm.h       | 43 ++++++++++++++++
> >   plat/common/include/asm.h           | 43 ++++++++++++++++
> >   plat/kvm/Config.uk                  |  2 +-
> >   plat/kvm/Makefile.uk                | 14 ++++++
> >   plat/kvm/arm/entry64.S              | 74 +++++++++++++++++++++++++++
> >   plat/kvm/arm/setup.c                | 26 ++++++++++
> >   9 files changed, 286 insertions(+), 1 deletion(-)
> >   create mode 100644 plat/common/include/arm/arm64/asm.h
> >   create mode 100644 plat/common/include/arm/asm.h
> >   create mode 100644 plat/common/include/asm.h
> >   create mode 100644 plat/kvm/arm/entry64.S
> >   create mode 100644 plat/kvm/arm/setup.c
> >
> > diff --git a/arch/arm/Compiler.uk b/arch/arm/Compiler.uk
> > index 147f662..3fd0f3f 100644
> > --- a/arch/arm/Compiler.uk
> > +++ b/arch/arm/Compiler.uk
> > @@ -1,3 +1,7 @@
> >   ifeq ($(CONFIG_UK_ARCH),arm)
> >     include $(CONFIG_UK_BASE)/arch/arm/arm/Compiler.uk
> >   endif
> > +
> > +ifeq ($(CONFIG_UK_ARCH),arm64)
> > +   include $(CONFIG_UK_BASE)/arch/arm/arm64/Compiler.uk
> > +endif
> > diff --git a/arch/arm/Makefile.uk b/arch/arm/Makefile.uk
> > index e59b2a3..11d81fb 100644
> > --- a/arch/arm/Makefile.uk
> > +++ b/arch/arm/Makefile.uk
> > @@ -2,3 +2,7 @@
> >   ifeq ($(CONFIG_UK_ARCH),arm)
> >     include $(CONFIG_UK_BASE)/arch/arm/arm/Makefile.uk
> >   endif
> > +
> > +ifeq ($(CONFIG_UK_ARCH),arm64)
> > +   include $(CONFIG_UK_BASE)/arch/arm/arm64/Makefile.uk
> > +endif
> > diff --git a/plat/common/include/arm/arm64/asm.h
> b/plat/common/include/arm/arm64/asm.h
> > new file mode 100644
> > index 0000000..ce361b1
> > --- /dev/null
> > +++ b/plat/common/include/arm/arm64/asm.h
> > @@ -0,0 +1,77 @@
> > +/* SPDX-License-Identifier: BSD-3-Clause */
> > +/*
> > + * Authors: Wei Chen <wei.chen@xxxxxxx>
> > + *
> > + * Copyright (c) 2018, Arm Ltd. All rights reserved.
> > + *
> > + * Redistribution and use in source and binary forms, with or without
> > + * modification, are permitted provided that the following conditions
> > + * are met:
> > + *
> > + * 1. Redistributions of source code must retain the above copyright
> > + *    notice, this list of conditions and the following disclaimer.
> > + * 2. Redistributions in binary form must reproduce the above copyright
> > + *    notice, this list of conditions and the following disclaimer in the
> > + *    documentation and/or other materials provided with the distribution.
> > + * 3. Neither the name of the copyright holder nor the names of its
> > + *    contributors may be used to endorse or promote products derived from
> > + *    this software without specific prior written permission.
> > + *
> > + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
> IS"
> > + * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
> THE
> > + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
> PURPOSE
> > + * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS
> BE
> > + * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
> > + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
> > + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
> > + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
> > + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
> > + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
> THE
> > + * POSSIBILITY OF SUCH DAMAGE.
> > + *
> > + * THIS HEADER MAY NOT BE EXTRACTED OR MODIFIED IN ANY WAY.
> > + */
> > +#ifndef __PLAT_CMN_ARM_ARM64_ASM_H__
> > +#define __PLAT_CMN_ARM_ARM64_ASM_H__
> > +
> > +#ifndef _BITUL
> 
> Why do you need this #ifndef?
> 

I copied it from ukvm code. It seems I just need #ifndef _BITUL
for following small section:
#define _BITUL(x)   (_AC(1,UL) << (x))
#define _BITULL(x)  (_AC(1,ULL) << (x))

> > +
> > +#ifdef __ASSEMBLY__
> > +
> > +/* Linkage for ARM */
> > +#define __ALIGN .align 2
> > +#define __ALIGN_STR ".align 2"
> > +
> > +#define ALIGN __ALIGN
> > +#define ALIGN_STR __ALIGN_STR
> > +
> > +#define ENTRY(name)        \
> > +.globl name;               \
> > +ALIGN;                     \
> > +name:
> > +
> > +#define GLOBAL(name)       \
> > +.globl name;               \
> > +name:
> > +
> > +#define END(name)  \
> > +.size name, .-name
> > +
> > +#define ENDPROC(name)      \
> > +.type name, %function;     \
> > +END(name)
> > +
> > +#define _AC(X,Y)    X
> > +#define _AT(T,X)    X
> > +
> > +#else
> > +#define __AC(X,Y)   (X##Y)
> > +#define _AC(X,Y)    __AC(X,Y)
> > +#define _AT(T,X)    ((T)(X))
> > +#endif
> > +
> > +#define _BITUL(x)   (_AC(1,UL) << (x))
> > +#define _BITULL(x)  (_AC(1,ULL) << (x))
> 
> Most of this code is not arm specific. Can this be defined in a common
> header?
> 

I was not sure how can this change affect the x86 code, so I placed
it for arm only. But as you mentioned, I will try.

> > +
> > +#endif
> > +#endif /* __PLAT_CMN_ARM_ARM64_ASM_H__ */
> > diff --git a/plat/common/include/arm/asm.h b/plat/common/include/arm/asm.h
> > new file mode 100644
> > index 0000000..ad07520
> > --- /dev/null
> > +++ b/plat/common/include/arm/asm.h
> > @@ -0,0 +1,43 @@
> > +/* SPDX-License-Identifier: BSD-3-Clause */
> > +/*
> > + * Authors: Wei Chen <wei.chen@xxxxxxx>
> > + *
> > + * Copyright (c) 2018, Arm Ltd. All rights reserved.
> > + *
> > + * Redistribution and use in source and binary forms, with or without
> > + * modification, are permitted provided that the following conditions
> > + * are met:
> > + *
> > + * 1. Redistributions of source code must retain the above copyright
> > + *    notice, this list of conditions and the following disclaimer.
> > + * 2. Redistributions in binary form must reproduce the above copyright
> > + *    notice, this list of conditions and the following disclaimer in the
> > + *    documentation and/or other materials provided with the distribution.
> > + * 3. Neither the name of the copyright holder nor the names of its
> > + *    contributors may be used to endorse or promote products derived from
> > + *    this software without specific prior written permission.
> > + *
> > + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
> IS"
> > + * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
> THE
> > + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
> PURPOSE
> > + * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS
> BE
> > + * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
> > + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
> > + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
> > + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
> > + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
> > + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
> THE
> > + * POSSIBILITY OF SUCH DAMAGE.
> > + *
> > + * THIS HEADER MAY NOT BE EXTRACTED OR MODIFIED IN ANY WAY.
> > + */
> > +#ifndef __PLAT_CMN_ARM_ASM_H__
> > +#define __PLAT_CMN_ARM_ASM_H__
> > +
> > +#if defined(__ARM_64__)
> > +#include "arm64/asm.h"
> > +#else
> > +#error "Add asm.h for current architecture."
> > +#endif
> > +
> > +#endif /* __PLAT_CMN_ARM_ASM_H__ */
> > diff --git a/plat/common/include/asm.h b/plat/common/include/asm.h
> > new file mode 100644
> > index 0000000..26576d5
> > --- /dev/null
> > +++ b/plat/common/include/asm.h
> 
> I don't think this header is useful because asm.h is only called from
> arm specific code.
> 

What did you mean by? I need a header for:
#define ENTRY(name)     \
.globl name;            \
ALIGN;                  \
name:

I don't want to define them in every file.

> > +.text
> > +ENTRY(_libkvmplat_entry)
> > +   /* Boot stack is placed after pagetable area temporarily */
> > +   ldr x26, =_end
> > +   add x26, x26, #PAGE_TABLE_SIZE
> > +   add x27, x26, #BOOT_STACK_SIZE
> > +
> > +   /*
> > +    * Clean the boot stack. As _end, PAGE_TABLE_SIZE and BOOT_STACK_SIZE
> > +    * are page_size alignment, the boot stack can be 64-bytes alignment
> > +    * too. Execute 4 stp consecutively without boundary check would be
> > +    * safe here.
> > +    */
> > +1:
> > +   stp xzr, xzr, [x26], #16
> > +   stp xzr, xzr, [x26], #16
> > +   stp xzr, xzr, [x26], #16
> > +   stp xzr, xzr, [x26], #16
> > +   cmp x26, x27
> > +   b.lo 1b
> 
> If you move them to BSS, then you don't have to care about initializing
> the stack and page-table.
> 

I have replied in previous patch.

> Cheers,
> 
> --
> Julien Grall
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