ref: b9101d2b5a8fd441c8c940222e1aa8072e5d0cee
dir: /ltrap.s/
#include "mem.h" #include "io.h" TEXT vectors(SB), $-4 MOVW 24(R15), R15 MOVW 24(R15), R15 MOVW 24(R15), R15 MOVW 24(R15), R15 MOVW 24(R15), R15 MOVW 24(R15), R15 MOVW 24(R15), R15 MOVW 24(R15), R15 TEXT vtable(SB), $-4 WORD $_vund(SB) WORD $_vund(SB) WORD $_vsvc(SB) WORD $_viabt(SB) WORD $_vdabt(SB) WORD $_vund(SB) WORD $_virq(SB) WORD $_vfiq(SB) TEXT _vsvc(SB), $-4 CLREX DSB /* stash in ureg */ MOVM.DB.W [R14], (R13) /* ureg->pc */ MOVW SPSR, R14 MOVM.DB.W [R14], (R13) /* ureg->psr */ MOVW $PsrMsvc, R14 MOVM.DB.W [R14], (R13) /* ureg->type */ /* save user regs. * not MOVM.DB.W.S because the saved value of R13 is undefined. * (arm v7 manual §A8.8.199) */ MOVM.DB.S [R0-R14], (R13) SUB $(15*4), R13 /* get our sb, mach, up */ MOVW $setR12(SB), R12 MOVW $(MACH(0)), R(Rmach) MOVW 8(R(Rmach)), R(Rup) /* make space for debugger and go to syscall passing ureg */ MOVW R13, R0 SUB $8, R13 BL syscall(SB) ADD $8, R13 /* restore link, spsr */ ADD $(15*4), R13 MOVW 8(R13), R14 MOVW 4(R13), R0 MOVW R0, SPSR /* restore user regs */ MOVM.DB.S (R13), [R0-R14] /* pop past ureg->type, ureg->psr and restore ureg->pc. * omap and others have RFE here but 5a has no idea about newer instructions * and simulates it with the MOVM below */ ADD $8, R13 MOVM.IA.S.W (R13), [R15] TEXT _viabt(SB), $-4 CLREX DSB MOVM.IA [R0-R4], (R13) MOVW $PsrMiabt, R0 B _vswitch TEXT _vdabt(SB), $-4 CLREX DSB MOVM.IA [R0-R4], (R13) MOVW $PsrMdabt, R0 B _vswitch TEXT _virq(SB), $-4 CLREX DSB MOVM.IA [R0-R4], (R13) MOVW $PsrMirq, R0 B _vswitch TEXT _vfiq(SB), $-4 CLREX DSB MOVM.IA [R0-R4], (R13) MOVW $PsrMfiq, R0 B _vswitch TEXT _vund(SB), $-4 CLREX DSB MOVM.IA [R0-R4], (R13) MOVW $PsrMund, R0 B _vswitch _vswitch: /* stash pointer to previous R0-R4, stash SPSR and R14 for ureg */ MOVW SPSR, R1 MOVW R14, R2 MOVW R13, R3 /* back to svc mode */ MOVW CPSR, R14 BIC $PsrMask, R14 ORR $(PsrDirq|PsrDfiq|PsrMsvc), R14 MOVW R14, CPSR /* from user or kernel mode? */ AND.S $0xf, R1, R4 BEQ _vuser /* from kernel mode */ /* set ureg->type, ureg->psr, ureg->pc */ MOVM.DB.W [R0-R2], (R13) MOVM.IA (R3), [R0-R4] /* save kernel regs * not MOVM.DB.W.S because the saved value of R13 is undefined. * (arm v7 manual §A8.8.199) */ MOVM.DB [R0-R14], (R13) SUB $(15*4), R13 /* get our sb, mach, up */ MOVW $setR12(SB), R12 /* make space for debugger and go to trap passing ureg */ MOVW R13, R0 SUB $8, R13 BL trap(SB) ADD $8, R13 /* restore link, spsr */ ADD $(15*4), R13 MOVW 8(R13), R14 MOVW 4(R13), R0 MOVW R0, SPSR /* restore kernel regs */ MOVM.DB (R13), [R0-R14] /* pop past ureg->type, ureg->psr, and restore ureg->pc. */ ADD $8, R13 MOVM.IA.S.W (R13), [R15] _vuser: /* from user mode */ /* set ureg->type, ureg->psr, ureg->pc */ MOVM.DB.W [R0-R2], (R13) MOVM.IA (R3), [R0-R4] /* save kernel regs * not MOVM.DB.W.S because the saved value of R13 is undefined. * (arm v7 manual §A8.8.199) */ MOVM.DB.S [R0-R14], (R13) SUB $(15*4), R13 /* get our sb, mach, up */ MOVW $setR12(SB), R12 MOVW $(MACH(0)), R(Rmach) MOVW 8(R(Rmach)), R(Rup) /* make space for debugger and go to trap passing ureg */ MOVW R13, R0 SUB $8, R13 BL trap(SB) ADD $8, R13 /* restore link, spsr */ ADD $(15*4), R13 MOVW 8(R13), R14 MOVW 4(R13), R0 MOVW R0, SPSR /* restore kernel regs */ MOVM.DB.S (R13), [R0-R14] /* pop past ureg->type, ureg->psr, and restore ureg->pc */ ADD $8, R13 MOVM.IA.S.W (R13), [R15] TEXT setR13(SB), $-4 MOVW 4(FP), R1 /* switch to new mode */ MOVW CPSR, R2 BIC $PsrMask, R2, R3 ORR R0, R3 MOVW R3, CPSR /* set r13 */ MOVW R1, R13 /* back to old mode */ MOVW R2, CPSR RET