Re: [PATCH v3 09/10] RISC-V: Add to build system

[Alexander Graf]

On 18.11.18 12:41, Bin Meng wrote:
> Hi Alex,
> 
> On Thu, Nov 15, 2018 at 1:27 AM Alexander Graf <address@hidden> wrote:
>>
>> This patch adds support for RISC-V to the grub build system. With this
>> patch, I can successfully build grub on RISC-V as a UEFI application.
>>
>> Signed-off-by: Alexander Graf <address@hidden>
>> Reviewed-by: Alistair Francis <address@hidden>
>>
>> ---
>>
>> v2 -> v3:
>>
>>   - Fix riscv32 target
>> ---
>>  configure.ac                 | 28 ++++++++++++++++++++++++++--
>>  gentpl.py                    | 11 +++++++----
>>  grub-core/Makefile.am        | 12 ++++++++++++
>>  grub-core/Makefile.core.def  | 29 +++++++++++++++++++++++++++++
>>  grub-core/commands/file.c    | 14 +++++++++++++-
>>  grub-core/kern/compiler-rt.c |  6 ++++--
>>  grub-core/kern/efi/mm.c      |  2 +-
>>  grub-core/kern/emu/cache.c   |  6 ++++++
>>  grub-core/kern/emu/cache_s.S |  1 +
>>  grub-core/kern/emu/lite.c    |  2 ++
>>  grub-core/lib/efi/halt.c     |  3 ++-
>>  grub-core/lib/setjmp.S       |  2 ++
>>  include/grub/compiler-rt.h   | 12 ++++++++----
>>  include/grub/efi/api.h       |  3 ++-
>>  include/grub/efi/efi.h       |  2 +-
>>  include/grub/misc.h          |  3 ++-
>>  include/grub/util/install.h  |  2 ++
>>  util/grub-install-common.c   |  2 ++
>>  util/grub-install.c          | 28 ++++++++++++++++++++++++++++
>>  util/grub-mknetdir.c         |  4 +++-
>>  util/grub-mkrescue.c         | 16 +++++++++++++++-
>>  util/mkimage.c               | 32 ++++++++++++++++++++++++++++++++
>>  22 files changed, 200 insertions(+), 20 deletions(-)
>>
> 
> Reviewed-by: Bin Meng <address@hidden>
> Tested-by: Bin Meng <address@hidden>
> 
> But please see one comment below:
> 
>> diff --git a/configure.ac b/configure.ac
>> index 5e63c4af3..2cc2ffb2c 100644
>> --- a/configure.ac
>> +++ b/configure.ac
>> @@ -104,6 +104,12 @@ case "$target_cpu" in
>>    aarch64*)
>>                 target_cpu=arm64
>>                 ;;
>> +  riscv32*)
>> +               target_cpu=riscv32
>> +               ;;
>> +  riscv64*)
>> +               target_cpu=riscv64
>> +               ;;
>>  esac
>>
>>  # Specify the platform (such as firmware).
>> @@ -127,6 +133,8 @@ if test "x$with_platform" = x; then
>>      ia64-*) platform=efi ;;
>>      arm-*) platform=uboot ;;
>>      arm64-*) platform=efi ;;
>> +    riscv32-*) platform=efi ;;
>> +    riscv64-*) platform=efi ;;
>>      *)
>>        AC_MSG_WARN([unsupported CPU: "$target_cpu" - only building 
>> utilities])
>>        platform=none
>> @@ -174,6 +182,8 @@ case "$target_cpu"-"$platform" in
>>    arm-coreboot) ;;
>>    arm-efi) ;;
>>    arm64-efi) ;;
>> +  riscv32-efi) ;;
>> +  riscv64-efi) ;;
>>    *-emu) ;;
>>    *-none) ;;
>>    *) AC_MSG_ERROR([platform "$platform" is not supported for target CPU 
>> "$target_cpu"]) ;;
>> @@ -826,6 +836,16 @@ if test x"$platform" != xemu ; then
>>         AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[]], [[]])],
>>                          
>> [grub_cv_target_cc_soft_float="-mgeneral-regs-only"], [])
>>      fi
>> +    if test "x$target_cpu" = xriscv32; then
>> +       CFLAGS="$TARGET_CFLAGS -march=rv32imac -mabi=ilp32 -Werror"
>> +       AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[]], [[]])],
>> +                        [grub_cv_target_cc_soft_float="-march=rv32imac 
>> -mabi=ilp32"], [])
>> +    fi
>> +    if test "x$target_cpu" = xriscv64; then
>> +       CFLAGS="$TARGET_CFLAGS -march=rv64imac -mabi=lp64 -Werror"
>> +       AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[]], [[]])],
>> +                        [grub_cv_target_cc_soft_float="-march=rv64imac 
>> -mabi=lp64"], [])
>> +    fi
>>      if test "x$target_cpu" = xia64; then
>>         CFLAGS="$TARGET_CFLAGS -mno-inline-float-divide -mno-inline-sqrt 
>> -Werror"
>>         AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[]], [[]])],
>> @@ -1141,7 +1161,7 @@ AC_SUBST(TARGET_LDFLAGS_OLDMAGIC)
>>
>>  LDFLAGS="$TARGET_LDFLAGS"
>>
>> -if test "$target_cpu" = x86_64 || test "$target_cpu" = sparc64 ; then
>> +if test "$target_cpu" = x86_64 || test "$target_cpu" = sparc64 || test 
>> "$target_cpu" = riscv64 ; then
>>    # Use large model to support 4G memory
>>    AC_CACHE_CHECK([whether option -mcmodel=large works], grub_cv_cc_mcmodel, 
>> [
>>      CFLAGS="$TARGET_CFLAGS -mcmodel=large"
>> @@ -1151,7 +1171,7 @@ if test "$target_cpu" = x86_64 || test "$target_cpu" = 
>> sparc64 ; then
>>    ])
>>    if test "x$grub_cv_cc_mcmodel" = xyes; then
>>      TARGET_CFLAGS="$TARGET_CFLAGS -mcmodel=large"
>> -  elif test "$target_cpu" = sparc64; then
>> +  elif test "$target_cpu" = sparc64 || test "$target_cpu" = riscv64; then
>>      TARGET_CFLAGS="$TARGET_CFLAGS -mcmodel=medany"
> 
> The patch does not indicate the code model explicitly for riscv32.
> It's better we pass the -mcmodel=medlow (suitable for riscv32) to the
> compiler in case the compiler is configured with a different code
> model by default.

I'm afraid there is no other model?

  https://gcc.gnu.org/onlinedocs/gcc/RISC-V-Options.html


Alex