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Diffstat (limited to 'src/pkg/runtime/sys_nacl_386.s')
| -rw-r--r-- | src/pkg/runtime/sys_nacl_386.s | 243 |
1 files changed, 243 insertions, 0 deletions
diff --git a/src/pkg/runtime/sys_nacl_386.s b/src/pkg/runtime/sys_nacl_386.s new file mode 100644 index 000000000..42ba0e0ed --- /dev/null +++ b/src/pkg/runtime/sys_nacl_386.s @@ -0,0 +1,243 @@ +// Copyright 2013 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +#include "zasm_GOOS_GOARCH.h" +#include "../../cmd/ld/textflag.h" +#include "syscall_nacl.h" + +#define NACL_SYSCALL(code) \ + MOVL $(0x10000 + ((code)<<5)), AX; CALL AX + +#define NACL_SYSJMP(code) \ + MOVL $(0x10000 + ((code)<<5)), AX; JMP AX + +TEXT runtime·exit(SB),NOSPLIT,$0 + NACL_SYSJMP(SYS_exit) + +TEXT runtime·exit1(SB),NOSPLIT,$0 + NACL_SYSJMP(SYS_thread_exit) + +TEXT runtime·open(SB),NOSPLIT,$0 + NACL_SYSJMP(SYS_open) + +TEXT runtime·close(SB),NOSPLIT,$0 + NACL_SYSJMP(SYS_close) + +TEXT runtime·read(SB),NOSPLIT,$0 + NACL_SYSJMP(SYS_read) + +TEXT syscall·naclWrite(SB), NOSPLIT, $12-16 + MOVL arg1+0(FP), DI + MOVL arg2+4(FP), SI + MOVL arg3+8(FP), DX + MOVL DI, 0(SP) + MOVL SI, 4(SP) + MOVL DX, 8(SP) + CALL runtime·write(SB) + MOVL AX, ret+16(FP) + RET + +TEXT runtime·write(SB),NOSPLIT,$0 + NACL_SYSJMP(SYS_write) + +TEXT runtime·nacl_exception_stack(SB),NOSPLIT,$0 + NACL_SYSJMP(SYS_exception_stack) + +TEXT runtime·nacl_exception_handler(SB),NOSPLIT,$0 + NACL_SYSJMP(SYS_exception_handler) + +TEXT runtime·nacl_sem_create(SB),NOSPLIT,$0 + NACL_SYSJMP(SYS_sem_create) + +TEXT runtime·nacl_sem_wait(SB),NOSPLIT,$0 + NACL_SYSJMP(SYS_sem_wait) + +TEXT runtime·nacl_sem_post(SB),NOSPLIT,$0 + NACL_SYSJMP(SYS_sem_post) + +TEXT runtime·nacl_mutex_create(SB),NOSPLIT,$0 + NACL_SYSJMP(SYS_mutex_create) + +TEXT runtime·nacl_mutex_lock(SB),NOSPLIT,$0 + NACL_SYSJMP(SYS_mutex_lock) + +TEXT runtime·nacl_mutex_trylock(SB),NOSPLIT,$0 + NACL_SYSJMP(SYS_mutex_trylock) + +TEXT runtime·nacl_mutex_unlock(SB),NOSPLIT,$0 + NACL_SYSJMP(SYS_mutex_unlock) + +TEXT runtime·nacl_cond_create(SB),NOSPLIT,$0 + NACL_SYSJMP(SYS_cond_create) + +TEXT runtime·nacl_cond_wait(SB),NOSPLIT,$0 + NACL_SYSJMP(SYS_cond_wait) + +TEXT runtime·nacl_cond_signal(SB),NOSPLIT,$0 + NACL_SYSJMP(SYS_cond_signal) + +TEXT runtime·nacl_cond_broadcast(SB),NOSPLIT,$0 + NACL_SYSJMP(SYS_cond_broadcast) + +TEXT runtime·nacl_cond_timed_wait_abs(SB),NOSPLIT,$0 + NACL_SYSJMP(SYS_cond_timed_wait_abs) + +TEXT runtime·nacl_thread_create(SB),NOSPLIT,$0 + NACL_SYSJMP(SYS_thread_create) + +TEXT runtime·mstart_nacl(SB),NOSPLIT,$0 + JMP runtime·mstart(SB) + +TEXT runtime·nacl_nanosleep(SB),NOSPLIT,$0 + NACL_SYSJMP(SYS_nanosleep) + +TEXT runtime·osyield(SB),NOSPLIT,$0 + NACL_SYSJMP(SYS_sched_yield) + +TEXT runtime·mmap(SB),NOSPLIT,$32 + MOVL arg1+0(FP), AX + MOVL AX, 0(SP) + MOVL arg2+4(FP), AX + MOVL AX, 4(SP) + MOVL arg3+8(FP), AX + MOVL AX, 8(SP) + MOVL arg4+12(FP), AX + MOVL AX, 12(SP) + MOVL arg5+16(FP), AX + MOVL AX, 16(SP) + MOVL arg6+20(FP), AX + MOVL AX, 24(SP) + MOVL $0, 28(SP) + LEAL 24(SP), AX + MOVL AX, 20(SP) + NACL_SYSCALL(SYS_mmap) + RET + +TEXT time·now(SB),NOSPLIT,$20 + MOVL $0, 0(SP) // real time clock + LEAL 8(SP), AX + MOVL AX, 4(SP) // timespec + NACL_SYSCALL(SYS_clock_gettime) + MOVL 8(SP), AX // low 32 sec + MOVL 12(SP), CX // high 32 sec + MOVL 16(SP), BX // nsec + + // sec is in AX, nsec in BX + MOVL AX, sec+0(FP) + MOVL CX, sec+4(FP) + MOVL BX, nsec+8(FP) + RET + +TEXT syscall·now(SB),NOSPLIT,$0 + JMP time·now(SB) + +TEXT runtime·nacl_clock_gettime(SB),NOSPLIT,$0 + NACL_SYSJMP(SYS_clock_gettime) + +TEXT runtime·nanotime(SB),NOSPLIT,$20 + MOVL $0, 0(SP) // real time clock + LEAL 8(SP), AX + MOVL AX, 4(SP) // timespec + NACL_SYSCALL(SYS_clock_gettime) + MOVL 8(SP), AX // low 32 sec + MOVL 16(SP), BX // nsec + + // sec is in AX, nsec in BX + // convert to DX:AX nsec + MOVL $1000000000, CX + MULL CX + ADDL BX, AX + ADCL $0, DX + + MOVL ret+0(FP), DI + MOVL AX, 0(DI) + MOVL DX, 4(DI) + RET + +TEXT runtime·setldt(SB),NOSPLIT,$8 + MOVL addr+4(FP), BX // aka base + ADDL $0x8, BX + MOVL BX, 0(SP) + NACL_SYSCALL(SYS_tls_init) + RET + +TEXT runtime·sigtramp(SB),NOSPLIT,$0 + get_tls(CX) + + // check that m exists + MOVL m(CX), BX + CMPL BX, $0 + JNE 6(PC) + MOVL $11, BX + MOVL BX, 0(SP) + MOVL $runtime·badsignal(SB), AX + CALL AX + JMP sigtramp_ret + + // save g + MOVL g(CX), DI + MOVL DI, 20(SP) + + // g = m->gsignal + MOVL m_gsignal(BX), BX + MOVL BX, g(CX) + + // copy arguments for sighandler + MOVL $11, 0(SP) // signal + MOVL $0, 4(SP) // siginfo + LEAL ctxt+4(FP), AX + MOVL AX, 8(SP) // context + MOVL DI, 12(SP) // g + + CALL runtime·sighandler(SB) + + // restore g + get_tls(CX) + MOVL 20(SP), BX + MOVL BX, g(CX) + +sigtramp_ret: + // Enable exceptions again. + NACL_SYSCALL(SYS_exception_clear_flag) + + // NaCl has abidcated its traditional operating system responsibility + // and declined to implement 'sigreturn'. Instead the only way to return + // to the execution of our program is to restore the registers ourselves. + // Unfortunately, that is impossible to do with strict fidelity, because + // there is no way to do the final update of PC that ends the sequence + // without either (1) jumping to a register, in which case the register ends + // holding the PC value instead of its intended value or (2) storing the PC + // on the stack and using RET, which imposes the requirement that SP is + // valid and that is okay to smash the word below it. The second would + // normally be the lesser of the two evils, except that on NaCl, the linker + // must rewrite RET into "POP reg; AND $~31, reg; JMP reg", so either way + // we are going to lose a register as a result of the incoming signal. + // Similarly, there is no way to restore EFLAGS; the usual way is to use + // POPFL, but NaCl rejects that instruction. We could inspect the bits and + // execute a sequence of instructions designed to recreate those flag + // settings, but that's a lot of work. + // + // Thankfully, Go's signal handlers never try to return directly to the + // executing code, so all the registers and EFLAGS are dead and can be + // smashed. The only registers that matter are the ones that are setting + // up for the simulated call that the signal handler has created. + // Today those registers are just PC and SP, but in case additional registers + // are relevant in the future (for example DX is the Go func context register) + // we restore as many registers as possible. + // + // We smash BP, because that's what the linker smashes during RET. + // + LEAL ctxt+4(FP), BP + ADDL $64, BP + MOVL 0(BP), AX + MOVL 4(BP), CX + MOVL 8(BP), DX + MOVL 12(BP), BX + MOVL 16(BP), SP + // 20(BP) is saved BP, never to be seen again + MOVL 24(BP), SI + MOVL 28(BP), DI + // 36(BP) is saved EFLAGS, never to be seen again + MOVL 32(BP), BP // saved PC + JMP BP |