Re: [Minios-devel] [UNIKRAFT PATCHv4 18/43] plat/include: Define address offsets of boot stack and pagetable

[Wei Chen <Wei.Chen@xxxxxxx>]

Hi Julien,

> -----Original Message-----
> From: Julien Grall <julien.grall@xxxxxxx>
> Sent: 2018年7月9日 4:19
> To: Wei Chen <Wei.Chen@xxxxxxx>; minios-devel@xxxxxxxxxxxxxxxxxxxx;
> simon.kuenzer@xxxxxxxxx
> Cc: Kaly Xin <Kaly.Xin@xxxxxxx>; nd <nd@xxxxxxx>
> Subject: Re: [Minios-devel] [UNIKRAFT PATCHv4 18/43] plat/include: Define
> address offsets of boot stack and pagetable
> 
> Hi Wei,
> 
> On 07/06/2018 10:03 AM, Wei Chen wrote:
> > If we place the boot stack and pagetable in BSS section. These
> > areas are not easy to be reused after changing to newstack. So
> 
> s/newstack/a new stack/ or "the new stack".
> 


Ok

> > in Arm64, we want to place the pagetable and boot stack behind
> 
> s/behind/after/

Got it.

> 
> > the end of image.
> > In this case, once we change to newstack or we have new pagetable,
> > these two areas can be reclaimed very easy.
> 
> I am wondering whether it would be worth to introduce an "init" section.
> This would make easier to reclaim the region and avoid hardcoded offset
> below.

If we have a lot of such init functions or data, it would be good to have
a init section. If not, the freed small init section it's not easy managed.
Because VA and PA is 1:1 mapped.

> 
> >
> > Signed-off-by: Wei Chen <Wei.Chen@xxxxxxx>
> > ---
> >   plat/common/include/arm/arm64/cpu_defs.h | 90 ++++++++++++++++++++++++
> >   plat/common/include/arm/cpu_defs.h       | 47 +++++++++++++
> >   2 files changed, 137 insertions(+)
> >   create mode 100644 plat/common/include/arm/arm64/cpu_defs.h
> >   create mode 100644 plat/common/include/arm/cpu_defs.h
> >
> > diff --git a/plat/common/include/arm/arm64/cpu_defs.h
> b/plat/common/include/arm/arm64/cpu_defs.h
> > new file mode 100644
> > index 0000000..b7eba93
> > --- /dev/null
> > +++ b/plat/common/include/arm/arm64/cpu_defs.h
> > @@ -0,0 +1,90 @@
> > +/* SPDX-License-Identifier: BSD-3-Clause */
> 
> IIRC, the goal of SPDX is to avoid to copy the full header afterwards.
> Can we please do one or the other but not both?
> 

Actually, the copyright header confused me a lot. I think I need a guide
@Simon Kuenzer (simon.kuenzer@xxxxxxxxx) : (

> > +/*
> > + * 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 __CPU_ARM_64_DEFS_H__
> > +#define __CPU_ARM_64_DEFS_H__
> > +
> > +#ifndef _BITUL
> > +
> > +#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))
> 
> None of the code above seem to belong to this patch.
> 

Ok, I will merge them to other patches.

> > +
> > +#endif
> > +
> > +/* Define the address offset of boot stack and pagetable */
> > +#define PAGE_SIZE  __PAGE_SIZE
> > +#define PAGE_SHIFT __PAGE_SHIFT
> > +#define STACK_SIZE __STACK_SIZE
> > +#define PGD_PAGE_OFFSET     0
> > +#define PUD_PAGE_OFFSET     (PGD_PAGE_OFFSET + PAGE_SIZE)
> > +#define PMD_PAGE_OFFSET     (PUD_PAGE_OFFSET + PAGE_SIZE * 2)
> > +#define PTE_PAGE_OFFSET     (PMD_PAGE_OFFSET + PAGE_SIZE)
> 
> PGD, PUD, PMD are linuxism that does not make sense without any
> documentation. Could we just name them L0, L1, L2...?
> 

Em, OK.

> > +#define PAGE_TABLE_SIZE     (PAGE_SIZE * 5)
> 
> You probably want to document where the 5 comes from and also the
> page-table area setup.

Yes, that makes sense.
> 
> > +#define STACK_TOP_OFFSET (PAGE_TABLE_SIZE + STACK_SIZE)
> > +
> > +#endif /* __CPU_ARM_64_DEFS_H__ */
> > diff --git a/plat/common/include/arm/cpu_defs.h
> b/plat/common/include/arm/cpu_defs.h
> > new file mode 100644
> > index 0000000..cd5a436
> > --- /dev/null
> > +++ b/plat/common/include/arm/cpu_defs.h
> > @@ -0,0 +1,47 @@
> > +/* 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_CPU_DEFS_H__
> > +#define __PLAT_CMN_ARM_CPU_DEFS_H__
> > +
> > +#if defined(__ARM_32__)
> > +#include "arm/cpu_defs.h"
> 
> Likely this belongs to a previous patch.
> 

Ok

> > +#elif defined(__ARM_64__)
> > +#include "arm64/cpu_defs.h"
> > +#else
> > +#error "Add cpu_defs.h for current architecture."
> > +#endif
> > +
> > +
> > +#endif /* __PLAT_CMN_ARM_CPU_DEFS_H__ */
> >
> 
> Cheers,
> 
> --
> Julien Grall
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