Re: [PATCH v3 08/10] RISC-V: Add auxiliary files

[Auer, Lukas]

On Mon, 2018-11-26 at 00:01 +0100, Alexander Graf wrote:
> 
> On 17.11.18 23:51, Auer, Lukas wrote:
> > On Wed, 2018-11-14 at 18:27 +0100, Alexander Graf wrote:
> > > To support a new architecture we need to provide a few helper
> > > functions
> > > for memory, cache, timer, etc support.
> > > 
> > > This patch adds the remainders of those. Some bits are still
> > > disabled,
> > > as I couldn't guarantee that we're always running on models / in
> > > modes
> > > where the respective hardware is available.
> > > 
> > > Signed-off-by: Alexander Graf <address@hidden>
> > > 
> > > ---
> > > 
> > > v2 -> v3:
> > > 
> > >   - Fix riscv32 target
> > > ---
> > >  grub-core/kern/riscv/cache.c       | 64
> > > +++++++++++++++++++++++++++++
> > >  grub-core/kern/riscv/cache_flush.S | 40 +++++++++++++++++++
> > >  grub-core/kern/riscv/efi/init.c    | 82
> > > ++++++++++++++++++++++++++++++++++++++
> > >  include/grub/riscv32/efi/memory.h  |  6 +++
> > >  include/grub/riscv32/time.h        | 28 +++++++++++++
> > >  include/grub/riscv32/types.h       | 34 ++++++++++++++++
> > >  include/grub/riscv64/efi/memory.h  |  6 +++
> > >  include/grub/riscv64/time.h        | 28 +++++++++++++
> > >  include/grub/riscv64/types.h       | 34 ++++++++++++++++
> > >  9 files changed, 322 insertions(+)
> > >  create mode 100644 grub-core/kern/riscv/cache.c
> > >  create mode 100644 grub-core/kern/riscv/cache_flush.S
> > >  create mode 100644 grub-core/kern/riscv/efi/init.c
> > >  create mode 100644 include/grub/riscv32/efi/memory.h
> > >  create mode 100644 include/grub/riscv32/time.h
> > >  create mode 100644 include/grub/riscv32/types.h
> > >  create mode 100644 include/grub/riscv64/efi/memory.h
> > >  create mode 100644 include/grub/riscv64/time.h
> > >  create mode 100644 include/grub/riscv64/types.h
> > > 
> > > diff --git a/grub-core/kern/riscv/cache.c b/grub-
> > > core/kern/riscv/cache.c
> > > new file mode 100644
> > > index 000000000..15dbe6927
> > > --- /dev/null
> > > +++ b/grub-core/kern/riscv/cache.c
> > > @@ -0,0 +1,64 @@
> > > +/*
> > > + *  GRUB  --  GRand Unified Bootloader
> > > + *  Copyright (C) 2013  Free Software Foundation, Inc.
> > > + *
> > > + *  GRUB is free software: you can redistribute it and/or modify
> > > + *  it under the terms of the GNU General Public License as
> > > published by
> > > + *  the Free Software Foundation, either version 3 of the
> > > License,
> > > or
> > > + *  (at your option) any later version.
> > > + *
> > > + *  GRUB is distributed in the hope that it will be useful,
> > > + *  but WITHOUT ANY WARRANTY; without even the implied warranty
> > > of
> > > + *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
> > > the
> > > + *  GNU General Public License for more details.
> > > + *
> > > + *  You should have received a copy of the GNU General Public
> > > License
> > > + *  along with GRUB.  If not, see <http://www.gnu.org/licenses/>
> > > .
> > > + */
> > > +
> > > +#include <grub/cache.h>
> > > +#include <grub/misc.h>
> > > +
> > > +static grub_int64_t dlinesz;
> > > +static grub_int64_t ilinesz;
> > > +
> > > +/* Prototypes for asm functions. */
> > > +void grub_arch_clean_dcache_range (grub_addr_t beg, grub_addr_t
> > > end,
> > > +                            grub_size_t line_size);
> > > +void grub_arch_invalidate_icache_range (grub_addr_t beg,
> > > grub_addr_t
> > > end,
> > > +                                 grub_size_t line_size);
> > > +
> > > +static void
> > > +probe_caches (void)
> > > +{
> > > +  /* TODO */
> > > +  dlinesz = 32;
> > > +  ilinesz = 32;
> > > +}
> > > +
> > > +void
> > > +grub_arch_sync_caches (void *address, grub_size_t len)
> > > +{
> > > +  grub_size_t start, end, max_align;
> > > +
> > > +  if (dlinesz == 0)
> > > +    probe_caches();
> > > +  if (dlinesz == 0)
> > > +    grub_fatal ("Unknown cache line size!");
> > > +
> > > +  max_align = dlinesz > ilinesz ? dlinesz : ilinesz;
> > > +
> > > +  start = ALIGN_DOWN ((grub_size_t) address, max_align);
> > > +  end = ALIGN_UP ((grub_size_t) address + len, max_align);
> > > +
> > > +  grub_arch_clean_dcache_range (start, end, dlinesz);
> > > +  grub_arch_invalidate_icache_range (start, end, ilinesz);
> > > +}
> > > +
> > > +void
> > > +grub_arch_sync_dma_caches (volatile void *address, grub_size_t
> > > len)
> > > +{
> > > +  /* DMA incoherent devices not supported yet */
> > > +  if (address || len || 1)
> > > +    return;
> > > +}
> > > diff --git a/grub-core/kern/riscv/cache_flush.S b/grub-
> > > core/kern/riscv/cache_flush.S
> > > new file mode 100644
> > > index 000000000..033a8aac3
> > > --- /dev/null
> > > +++ b/grub-core/kern/riscv/cache_flush.S
> > > @@ -0,0 +1,40 @@
> > > +/*
> > > + *  GRUB  --  GRand Unified Bootloader
> > > + *  Copyright (C) 2013  Free Software Foundation, Inc.
> > > + *
> > > + *  GRUB is free software: you can redistribute it and/or modify
> > > + *  it under the terms of the GNU General Public License as
> > > published by
> > > + *  the Free Software Foundation, either version 3 of the
> > > License,
> > > or
> > > + *  (at your option) any later version.
> > > + *
> > > + *  GRUB is distributed in the hope that it will be useful,
> > > + *  but WITHOUT ANY WARRANTY; without even the implied warranty
> > > of
> > > + *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
> > > the
> > > + *  GNU General Public License for more details.
> > > + *
> > > + *  You should have received a copy of the GNU General Public
> > > License
> > > + *  along with GRUB.  If not, see <http://www.gnu.org/licenses/>
> > > .
> > > + */
> > > +
> > > +#include <grub/symbol.h>
> > > +
> > > + .file   "cache_flush.S"
> > > + .text
> > > +
> > > +/*
> > > + * Simple cache maintenance functions
> > > + */
> > > +
> > > +// a0 - *beg (inclusive)
> > > +// a1 - *end (exclusive)
> > > +// a2 - line size
> > > +FUNCTION(grub_arch_clean_dcache_range)
> > > + // TODO
> > > + ret
> > > +
> > > +// a0 - *beg (inclusive)
> > > +// a1 - *end (exclusive)
> > > +// a2 - line size
> > > +FUNCTION(grub_arch_invalidate_icache_range)
> > > + // TODO
> > > + ret
> > 
> > You can use fence.i here to synchronize writes to instruction
> > memory
> > with instruction fetches. Essentially a instruction cache flush,
> > but
> > different processors may choose different implementations for it.
> 
> I suppose that one is implemented by every reasonable core? I'll add
> it
> then :).
> 
> 
> Thanks!
> 
> Alex

Yes definitely, the RISC-V Linux kernel would not work without it.

Lukas