/* * Does a 32-bit syscall. Called with IRQs on in CONTEXT_KERNEL. Does * all entry and exit work and returns with IRQs off. This function is * extremely hot in workloads that use it, and it's usually called from * do_fast_syscall_32, so forcibly inline it to improve performance. */ static __always_inline void do_syscall_32_irqs_on(struct pt_regs *regs) { struct thread_info *ti = current_thread_info(); unsigned int nr = (unsigned int)regs->orig_ax; #ifdef CONFIG_IA32_EMULATION current->thread.status |= TS_COMPAT; #endif if (READ_ONCE(ti->flags) & _TIF_WORK_SYSCALL_ENTRY) { /* * Subtlety here: if ptrace pokes something larger than * 2^32-1 into orig_ax, this truncates it. This may or * may not be necessary, but it matches the old asm * behavior. */ nr = syscall_trace_enter(regs); } if (likely(nr < IA32_NR_syscalls)) { /* * It's possible that a 32-bit syscall implementation * takes a 64-bit parameter but nonetheless assumes that * the high bits are zero. Make sure we zero-extend all * of the args. */ regs->ax = ia32_sys_call_table[nr]( (unsigned int)regs->bx, (unsigned int)regs->cx, (unsigned int)regs->dx, (unsigned int)regs->si, (unsigned int)regs->di, (unsigned int)regs->bp); } syscall_return_slowpath(regs); }
__visible void do_syscall_64(unsigned long nr, struct pt_regs *regs) { struct thread_info *ti; enter_from_user_mode(); local_irq_enable(); ti = current_thread_info(); if (READ_ONCE(ti->flags) & _TIF_WORK_SYSCALL_ENTRY) nr = syscall_trace_enter(regs); /* * NB: Native and x32 syscalls are dispatched from the same * table. The only functional difference is the x32 bit in * regs->orig_ax, which changes the behavior of some syscalls. */ nr &= __SYSCALL_MASK; if (likely(nr < NR_syscalls)) { nr = array_index_nospec(nr, NR_syscalls); regs->ax = sys_call_table[nr](regs); } syscall_return_slowpath(regs); }