Hi Willy, > On Tue, Jul 25, 2023 at 07:02:55PM +0800, Zhangjin Wu wrote: > > > > With this new syscall.h, to support my_syscall<N>, the arch-<ARCH>.h > > > > will only require to add ~10 lines to define their own syscall > > > > instructions, registers and clobberlist, which looks like this (for > > > > powerpc): > > > > > > > > #define _NOLIBC_SYSCALL_CALL "sc; bns+ 1f; neg %0, %0; 1:" > > > > > > > > /* PowerPC doesn't always restore r3-r12 for us */ > > > > #define _NOLIBC_SYSCALL_CLOBBERLIST > > > > "memory", "cr0", "r12", "r11", "r10", "r9", "r8", "r7", "r6", "r5", "r4" > > > > > > > > /* PowerPC write GPRS in kernel side but not restore them */ > > > > #define _NOLIBC_GPRS_AS_OUTPUT_OPERANDS > > > > > > > > #define _NOLIBC_REG_NUM "r0" > > > > #define _NOLIBC_REG_RET "r3" > > > > #define _NOLIBC_REG_arg1 "r3" > > > > #define _NOLIBC_REG_arg2 "r4" > > > > #define _NOLIBC_REG_arg3 "r5" > > > > #define _NOLIBC_REG_arg4 "r6" > > > > #define _NOLIBC_REG_arg5 "r7" > > > > #define _NOLIBC_REG_arg6 "r8" > > > > > > > > Before: > > > > > > > > $ ls tools/include/nolibc/arch-*.h | while read f; do git show dfef4fc45d5713eb23d87f0863aff9c33bd4bfaf:$f 2>/dev/null | wc -l | tr -d '\n'; echo " $f"; done > > > > 157 tools/include/nolibc/arch-aarch64.h > > > > 199 tools/include/nolibc/arch-arm.h > > > > 178 tools/include/nolibc/arch-i386.h > > > > 164 tools/include/nolibc/arch-loongarch.h > > > > 195 tools/include/nolibc/arch-mips.h > > > > 0 tools/include/nolibc/arch-powerpc.h > > > > 160 tools/include/nolibc/arch-riscv.h > > > > 186 tools/include/nolibc/arch-s390.h > > > > 176 tools/include/nolibc/arch-x86_64.h > > > > > > > > After: > > > > > > > > $ wc -l tools/include/nolibc/arch-*.h > > > > 54 tools/include/nolibc/arch-aarch64.h > > > > 84 tools/include/nolibc/arch-arm.h > > > > 90 tools/include/nolibc/arch-i386.h /* the last one use stack to pass arguments, reserve as-is */ > > > > 59 tools/include/nolibc/arch-loongarch.h > > > > 120 tools/include/nolibc/arch-mips.h /* the last two use stack to pass arguments, reserve as-is */ > > > > 73 tools/include/nolibc/arch-powerpc.h > > > > 58 tools/include/nolibc/arch-riscv.h > > > > 87 tools/include/nolibc/arch-s390.h > > > > 67 tools/include/nolibc/arch-x86_64.h > > > > > > > > syscall.h itself: > > > > > > > > $ wc -l tools/include/nolibc/syscall.h > > > > 112 tools/include/nolibc/syscall.h > > > > > [...] > > Hoping this clarifies my position on this. > Willy, Thanks very much for your detailed reply, based on your reply, I plan to renew the powerpc patchset itself at first since both you and Thomas have already reviewed it carefully. After that, I will come back to read your reply again and discuss more about our new syscall.h, I still think it is something valuable to take a look at, although something about it still need more attention, perhaps a RFC patchset is better for more discuss, it may show us the profile easily. Best regards, Zhangjin > Thanks, > Willy
