Arm Linux系统调用流程详细解析SWI

r, pc, #16 ; lr = __sys_trace_return*/adrsvc al, lr, __sys_trace_return @ return addressadd r1, sp, #S_R0 + S_OFF @ pointer to regscmp scno, #NR_syscalls @ check upper syscall limitldmccia r1, {r0 - r3} @ have to reload r0 - r3ldrcc pc, [tbl, scno, lsl #2] @ call sys_* routineb 2b__sys_trace_return:str r0, [sp, #S_R0 + S_OFF]! @ save returned r0mov r1, spmov r0, #1 @ trace exit [IP = 1]bl SYMBOL_NAME(syscall_trace)b ret_disable_irq.align 5#ifdef CONFIG_ALIGNMENT_TRAP.type __cr_alignment, #object__cr_alignment:.word SYMBOL_NAME(cr_alignment)#endif.type sys_call_table, #objectENTRY(sys_call_table)#include "calls.S"