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

[Alexander Graf]

On 21.11.18 17:02, Daniel Kiper wrote:
> On Wed, Nov 14, 2018 at 06:27:37PM +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.
> 
> s/2013/2018/
> 
>> + *
>> + *  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;
> 
> I think that you can drop the code and leave the comment here.

IIRC I had issues with some gcc versions that complained about unused
arguments in that case.

> 
>> +}
>> 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
> 
> Please do not use "//" for comments.

Ok.

> 
>> +FUNCTION(grub_arch_clean_dcache_range)
>> +    // TODO
>> +    ret
>> +
>> +// a0 - *beg (inclusive)
>> +// a1 - *end (exclusive)
>> +// a2 - line size
> 
> Ditto.
> 
>> +FUNCTION(grub_arch_invalidate_icache_range)
>> +    // TODO
> 
> Ditto.
> 
>> +    ret
>> diff --git a/grub-core/kern/riscv/efi/init.c 
>> b/grub-core/kern/riscv/efi/init.c
>> new file mode 100644
>> index 000000000..199de08a7
>> --- /dev/null
>> +++ b/grub-core/kern/riscv/efi/init.c
>> @@ -0,0 +1,82 @@
>> +/* init.c - initialize a riscv-based EFI system */
>> +/*
>> + *  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/env.h>
>> +#include <grub/kernel.h>
>> +#include <grub/misc.h>
>> +#include <grub/mm.h>
>> +#include <grub/time.h>
>> +#include <grub/efi/efi.h>
>> +#include <grub/loader.h>
>> +
>> +static grub_uint64_t timer_frequency_in_khz;
>> +
>> +static grub_uint64_t
>> +grub_efi_get_time_ms (void)
>> +{
>> +  grub_uint64_t tmr;
>> +
>> +#if 0
>> +#if __riscv_xlen == 64
>> +  asm volatile ("rdtime %0" : "=r" (tmr));
>> +#else
>> +  grub_uint32_t lo, hi, tmp;
>> +  asm volatile (
>> +    "1:\n"
>> +    "rdtimeh %0\n"
>> +    "rdtime %1\n"
>> +    "rdtimeh %2\n"
>> +    "bne %0, %2, 1b"
>> +    : "=&r" (hi), "=&r" (lo), "=&r" (tmp));
>> +  tmr = ((u64)hi << 32) | lo;
>> +#endif
> 
> I would drop this piece of dead code.

I'd much rather revive the dead code and drop the hack :). Thanks for
spotting it!

Alex