ref: c9d2fecbd06d0e9efc2fa16f214f1612a9a40d93
dir: /sys/src/9/xen/xen.s/
#include "xendefs.h" #include "mem.h" #define ENTRY(X) TEXT X(SB), $0 /* * XXX there's a race in here because we can get an upcall * betwen the spllo() (in xenupcall) and the rti. This will make * handlers stack, which could lead to a blown stack. Probably * not worth fixing (but possibly worth detecting and panicing). * * For fun get some popcorn and turn off the lights and read the * linux solution (search for scrit/ecrit). */ ENTRY(hypervisor_callback) SUBL $8, SP /* space for ecode and trap type */ PUSHL DS /* save DS */ PUSHL $(KDSEL) POPL DS /* fix up DS */ PUSHL ES /* save ES */ PUSHL $(KDSEL) POPL ES /* fix up ES */ PUSHL FS /* save the rest of the Ureg struct */ PUSHL GS PUSHAL PUSHL SP /* Ureg* argument to trap */ CALL xenupcall+0(SB) POPL AX POPAL POPL GS POPL FS POPL ES POPL DS ADDL $8, SP /* pop error code and trap type */ IRETL /* Hypervisor uses this for application faults while it executes.*/ ENTRY(failsafe_callback) IRETL PUSHL AX CALL install_safe_pf_handler(SB) MOVL 32(SP), BX MOVW BX, DS MOVL 36(SP), BX MOVW BX, ES MOVL 40(SP), BX MOVW BX, FS MOVL 44(SP), BX MOVW BX, GS CALL install_normal_pf_handler(SB) POPL AX ADDL $16, SP IRETL /* xen traps with varying argument counts */ TEXT xencall6(SB), $0 MOVL VDI+20(FP), DI TEXT xencall5(SB), $0 MOVL VSI+16(FP), SI TEXT xencall4(SB), $0 MOVL VDX+12(FP), DX TEXT xencall3(SB), $0 MOVL VCX+8(FP), CX TEXT xencall2(SB), $0 MOVL VBX+4(FP), BX TEXT xencall1(SB), $0 MOVL op+0(FP), AX INT $0x82 RET