guoren@xxxxxxxxxx writes: > From: Guo Ren <guoren@xxxxxxxxxxxxxxxxx> > > This patch converts riscv to use the generic entry infrastructure from > kernel/entry/*. The generic entry makes maintainers' work easier and > codes more elegant. Here are the changes than before: > > - More clear entry.S with handle_exception and ret_from_exception > - Get rid of complex custom signal implementation > - More readable syscall procedure > - Little modification on ret_from_fork & ret_from_kernel_thread > - Wrap with irqentry_enter/exit and syscall_enter/exit_from_user_mode > - Use the standard preemption code instead of custom > > Signed-off-by: Guo Ren <guoren@xxxxxxxxxxxxxxxxx> > Signed-off-by: Guo Ren <guoren@xxxxxxxxxx> > Suggested-by: Huacai Chen <chenhuacai@xxxxxxxxxx> > Tested-by: Yipeng Zou <zouyipeng@xxxxxxxxxx> > --- [...] > diff --git a/arch/riscv/kernel/sys_riscv.c b/arch/riscv/kernel/sys_riscv.c > index 5d3f2fbeb33c..c86d0eafdf6a 100644 > --- a/arch/riscv/kernel/sys_riscv.c > +++ b/arch/riscv/kernel/sys_riscv.c > @@ -5,8 +5,10 @@ > * Copyright (C) 2017 SiFive > */ > > +#include <linux/entry-common.h> > #include <linux/syscalls.h> > #include <asm/unistd.h> > +#include <asm/syscall.h> > #include <asm/cacheflush.h> > #include <asm-generic/mman-common.h> > > @@ -69,3 +71,28 @@ SYSCALL_DEFINE3(riscv_flush_icache, uintptr_t, start, uintptr_t, end, > > return 0; > } > + > +typedef long (*syscall_t)(ulong, ulong, ulong, ulong, ulong, ulong, ulong); > + > +asmlinkage void do_sys_ecall_u(struct pt_regs *regs) > +{ > + syscall_t syscall; > + ulong nr = regs->a7; > + > + regs->epc += 4; > + regs->orig_a0 = regs->a0; > + regs->a0 = -ENOSYS; > + > + nr = syscall_enter_from_user_mode(regs, nr); > +#ifdef CONFIG_COMPAT > + if ((regs->status & SR_UXL) == SR_UXL_32) > + syscall = compat_sys_call_table[nr]; > + else > +#endif > + syscall = sys_call_table[nr]; > + > + if (nr < NR_syscalls) > + regs->a0 = syscall(regs->orig_a0, regs->a1, regs->a2, > + regs->a3, regs->a4, regs->a5, > regs->a6); Now that we're doing the "pt_regs to call" dance, it would make sense to introduce a syscall wrapper (like x86 and arm64) for riscv, so that we don't need to unwrap all regs for all syscalls (See __MAP() in include/linux/syscalls.h). That would be an optimization, so it could be done as a follow-up, and not part of the series. Björn