[PATCH 0/1] Only pass the minimum number of syscall arguments (RISC-V)

[Corinna Vinschen]

On Feb 10 21:19, Georg Sauthoff wrote:
> As is, the RISC-V syscall code unconditionally sets all possible syscall
> arguments even if the syscall requires fewer.
> 
> For example, the instruction sequence for a exit syscall looked like
> this:
> 
>     li    a0, 1   # in ther caller of exit()
>     # ...         # in newlib:
>     li    a1, 0   # unused arguments
>     li    a2, 0
>     li    a3, 0
>     li    a4, 0
>     li    a5, 0
>     li    a7, 93  # exit syscall number
> 
> (i.e. the binary contains then 5 superfluous instructions for this
> one argument syscall)
> 
> This patch changes the RISC-V syscall code such that only the required
> syscall argument registers are set.
> 
> Georg Sauthoff (1):
>   Only pass the minimum number of syscall arguments
> 
>  libgloss/riscv/internal_syscall.h | 41 ++++++++++++++++++++++---------
>  libgloss/riscv/sys_access.c       |  2 +-
>  libgloss/riscv/sys_close.c        |  2 +-
>  libgloss/riscv/sys_exit.c         |  2 +-
>  libgloss/riscv/sys_faccessat.c    |  2 +-
>  libgloss/riscv/sys_fstat.c        |  2 +-
>  libgloss/riscv/sys_fstatat.c      |  2 +-
>  libgloss/riscv/sys_gettimeofday.c |  2 +-
>  libgloss/riscv/sys_link.c         |  2 +-
>  libgloss/riscv/sys_lseek.c        |  2 +-
>  libgloss/riscv/sys_lstat.c        |  2 +-
>  libgloss/riscv/sys_open.c         |  2 +-
>  libgloss/riscv/sys_openat.c       |  2 +-
>  libgloss/riscv/sys_read.c         |  2 +-
>  libgloss/riscv/sys_sbrk.c         |  4 +--
>  libgloss/riscv/sys_stat.c         |  2 +-
>  libgloss/riscv/sys_unlink.c       |  2 +-
>  libgloss/riscv/sys_write.c        |  2 +-
>  18 files changed, 48 insertions(+), 29 deletions(-)
> 
> -- 
> 2.24.1

Pushed.


Thanks,
Corinna

-- 
Corinna Vinschen
Cygwin Maintainer
Red Hat
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