// SPDX-License-Identifier: GPL-2.0 #include <linux/compiler.h>#include <linux/context_tracking.h>#include <linux/errno.h>#include <linux/nospec.h>#include <linux/ptrace.h>#include <linux/syscalls.h> #include <asm/daifflags.h>#include <asm/debug-monitors.h>#include <asm/fpsimd.h>#include <asm/syscall.h>#include <asm/thread_info.h>#include <asm/unistd.h> long compat_arm_syscall(struct pt_regs *regs, int scno);long sys_ni_syscall(void); static long do_ni_syscall(struct pt_regs *regs, int scno){#ifdef CONFIG_COMPAT	long ret;	if (is_compat_task()) {		ret = compat_arm_syscall(regs, scno);		if (ret != -ENOSYS)			return ret;	}#endif 	return sys_ni_syscall();} static long __invoke_syscall(struct pt_regs *regs, syscall_fn_t syscall_fn){	return syscall_fn(regs);} static void invoke_syscall(struct pt_regs *regs, unsigned int scno,			   unsigned int sc_nr,			   const syscall_fn_t syscall_table[]){	long ret; 	if (scno < sc_nr) {		syscall_fn_t syscall_fn;		syscall_fn = syscall_table[array_index_nospec(scno, sc_nr)];		ret = __invoke_syscall(regs, syscall_fn);	} else {		ret = do_ni_syscall(regs, scno);	} 	regs->regs[0] = ret;} static inline bool has_syscall_work(unsigned long flags){	return unlikely(flags & _TIF_SYSCALL_WORK);} int syscall_trace_enter(struct pt_regs *regs);void syscall_trace_exit(struct pt_regs *regs); #ifdef CONFIG_ARM64_ERRATUM_1463225DECLARE_PER_CPU(int, __in_cortex_a76_erratum_1463225_wa); static void cortex_a76_erratum_1463225_svc_handler(void){	u32 reg, val; 	if (!unlikely(test_thread_flag(TIF_SINGLESTEP)))		return; 	if (!unlikely(this_cpu_has_cap(ARM64_WORKAROUND_1463225)))		return; 	__this_cpu_write(__in_cortex_a76_erratum_1463225_wa, 1);	reg = read_sysreg(mdscr_el1);	val = reg | DBG_MDSCR_SS | DBG_MDSCR_KDE;	write_sysreg(val, mdscr_el1);	asm volatile("msr daifclr, #8");	isb(); 	/* We will have taken a single-step exception by this point */ 	write_sysreg(reg, mdscr_el1);	__this_cpu_write(__in_cortex_a76_erratum_1463225_wa, 0);}#elsestatic void cortex_a76_erratum_1463225_svc_handler(void) { }#endif /* CONFIG_ARM64_ERRATUM_1463225 */ static void el0_svc_common(struct pt_regs *regs, int scno, int sc_nr,			   const syscall_fn_t syscall_table[]){	unsigned long flags = current_thread_info()->flags; 	regs->orig_x0 = regs->regs[0];	regs->syscallno = scno; 	cortex_a76_erratum_1463225_svc_handler();	local_daif_restore(DAIF_PROCCTX);	user_exit(); 	if (has_syscall_work(flags)) {		/* set default errno for user-issued syscall(-1) */		if (scno == NO_SYSCALL)			regs->regs[0] = -ENOSYS;		scno = syscall_trace_enter(regs);		if (scno == NO_SYSCALL)			goto trace_exit;	} 	invoke_syscall(regs, scno, sc_nr, syscall_table); 	/*	 * The tracing status may have changed under our feet, so we have to	 * check again. However, if we were tracing entry, then we always trace	 * exit regardless, as the old entry assembly did.	 */	if (!has_syscall_work(flags) && !IS_ENABLED(CONFIG_DEBUG_RSEQ)) {		local_daif_mask();		flags = current_thread_info()->flags;		if (!has_syscall_work(flags)) {			/*			 * We're off to userspace, where interrupts are			 * always enabled after we restore the flags from			 * the SPSR.			 */			trace_hardirqs_on();			return;		}		local_daif_restore(DAIF_PROCCTX);	} trace_exit:	syscall_trace_exit(regs);} static inline void sve_user_discard(void){	if (!system_supports_sve())		return; 	clear_thread_flag(TIF_SVE); 	/*	 * task_fpsimd_load() won't be called to update CPACR_EL1 in	 * ret_to_user unless TIF_FOREIGN_FPSTATE is still set, which only	 * happens if a context switch or kernel_neon_begin() or context	 * modification (sigreturn, ptrace) intervenes.	 * So, ensure that CPACR_EL1 is already correct for the fast-path case.	 */	sve_user_disable();} asmlinkage void el0_svc_handler(struct pt_regs *regs){	sve_user_discard();	el0_svc_common(regs, regs->regs[8], __NR_syscalls, sys_call_table);} #ifdef CONFIG_COMPATasmlinkage void el0_svc_compat_handler(struct pt_regs *regs){	el0_svc_common(regs, regs->regs[7], __NR_compat_syscalls,		       compat_sys_call_table);}#endif