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go/src/runtime/sys_linux_mips64x.s
Austin Clements bb6309cd63 runtime: inform arena placement using sbrk(0)
On 32-bit architectures (or if we fail to map a 64-bit-style arena),
we try to map the heap arena just above the end of the process image.
While we can accept any address, using lower addresses is preferable
because lower addresses cause us to map less of the heap bitmap.

However, if a program is linked against C code that has global
constructors, those constructors may call brk/sbrk to allocate memory
(e.g., many C malloc implementations do this for small allocations).
The brk also starts just above the process image, so this may adjust
the brk past the beginning of where we want to put the heap arena. In
this case, the kernel will pick a different address for the arena and
it will usually be very high (at least, as these things go in a 32-bit
address space).

Fix this by consulting the current value of the brk and using this in
addition to the end of the process image to compute the initial arena
placement.

This is implemented only on Linux currently, since we have no evidence
that it's an issue on any other OSes.

Fixes #19831.

Change-Id: Id64b45d08d8c91e4f50d92d0339146250b04f2f8
Reviewed-on: https://go-review.googlesource.com/39810
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2017-04-21 14:34:10 +00:00

439 lines
8.4 KiB
ArmAsm

// Copyright 2015 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.
// +build linux
// +build mips64 mips64le
//
// System calls and other sys.stuff for mips64, Linux
//
#include "go_asm.h"
#include "go_tls.h"
#include "textflag.h"
#define SYS_exit 5058
#define SYS_read 5000
#define SYS_write 5001
#define SYS_open 5002
#define SYS_close 5003
#define SYS_getpid 5038
#define SYS_kill 5060
#define SYS_fcntl 5080
#define SYS_gettimeofday 5094
#define SYS_mmap 5009
#define SYS_munmap 5011
#define SYS_setitimer 5036
#define SYS_clone 5055
#define SYS_newselect 5022
#define SYS_sched_yield 5023
#define SYS_rt_sigreturn 5211
#define SYS_rt_sigaction 5013
#define SYS_rt_sigprocmask 5014
#define SYS_sigaltstack 5129
#define SYS_getrlimit 5095
#define SYS_madvise 5027
#define SYS_mincore 5026
#define SYS_gettid 5178
#define SYS_tkill 5192
#define SYS_futex 5194
#define SYS_sched_getaffinity 5196
#define SYS_exit_group 5205
#define SYS_epoll_create 5207
#define SYS_epoll_ctl 5208
#define SYS_epoll_wait 5209
#define SYS_clock_gettime 5222
#define SYS_epoll_create1 5285
#define SYS_brk 5012
TEXT runtime·exit(SB),NOSPLIT,$-8-4
MOVW code+0(FP), R4
MOVV $SYS_exit_group, R2
SYSCALL
RET
TEXT runtime·exit1(SB),NOSPLIT,$-8-4
MOVW code+0(FP), R4
MOVV $SYS_exit, R2
SYSCALL
RET
TEXT runtime·open(SB),NOSPLIT,$-8-20
MOVV name+0(FP), R4
MOVW mode+8(FP), R5
MOVW perm+12(FP), R6
MOVV $SYS_open, R2
SYSCALL
BEQ R7, 2(PC)
MOVW $-1, R2
MOVW R2, ret+16(FP)
RET
TEXT runtime·closefd(SB),NOSPLIT,$-8-12
MOVW fd+0(FP), R4
MOVV $SYS_close, R2
SYSCALL
BEQ R7, 2(PC)
MOVW $-1, R2
MOVW R2, ret+8(FP)
RET
TEXT runtime·write(SB),NOSPLIT,$-8-28
MOVV fd+0(FP), R4
MOVV p+8(FP), R5
MOVW n+16(FP), R6
MOVV $SYS_write, R2
SYSCALL
BEQ R7, 2(PC)
MOVW $-1, R2
MOVW R2, ret+24(FP)
RET
TEXT runtime·read(SB),NOSPLIT,$-8-28
MOVW fd+0(FP), R4
MOVV p+8(FP), R5
MOVW n+16(FP), R6
MOVV $SYS_read, R2
SYSCALL
BEQ R7, 2(PC)
MOVW $-1, R2
MOVW R2, ret+24(FP)
RET
TEXT runtime·getrlimit(SB),NOSPLIT,$-8-20
MOVW kind+0(FP), R4 // _RLIMIT_AS = 6 on linux/mips
MOVV limit+8(FP), R5
MOVV $SYS_getrlimit, R2
SYSCALL
MOVW R2, ret+16(FP)
RET
TEXT runtime·usleep(SB),NOSPLIT,$16-4
MOVWU usec+0(FP), R3
MOVV R3, R5
MOVW $1000000, R4
DIVVU R4, R3
MOVV LO, R3
MOVV R3, 8(R29)
MULVU R3, R4
MOVV LO, R4
SUBVU R4, R5
MOVV R5, 16(R29)
// select(0, 0, 0, 0, &tv)
MOVW $0, R4
MOVW $0, R5
MOVW $0, R6
MOVW $0, R7
ADDV $8, R29, R8
MOVV $SYS_newselect, R2
SYSCALL
RET
TEXT runtime·gettid(SB),NOSPLIT,$0-4
MOVV $SYS_gettid, R2
SYSCALL
MOVW R2, ret+0(FP)
RET
TEXT runtime·raise(SB),NOSPLIT,$-8
MOVV $SYS_gettid, R2
SYSCALL
MOVW R2, R4 // arg 1 tid
MOVW sig+0(FP), R5 // arg 2
MOVV $SYS_tkill, R2
SYSCALL
RET
TEXT runtime·raiseproc(SB),NOSPLIT,$-8
MOVV $SYS_getpid, R2
SYSCALL
MOVW R2, R4 // arg 1 pid
MOVW sig+0(FP), R5 // arg 2
MOVV $SYS_kill, R2
SYSCALL
RET
TEXT runtime·setitimer(SB),NOSPLIT,$-8-24
MOVW mode+0(FP), R4
MOVV new+8(FP), R5
MOVV old+16(FP), R6
MOVV $SYS_setitimer, R2
SYSCALL
RET
TEXT runtime·mincore(SB),NOSPLIT,$-8-28
MOVV addr+0(FP), R4
MOVV n+8(FP), R5
MOVV dst+16(FP), R6
MOVV $SYS_mincore, R2
SYSCALL
SUBVU R2, R0, R2 // caller expects negative errno
MOVW R2, ret+24(FP)
RET
// func walltime() (sec int64, nsec int32)
TEXT runtime·walltime(SB),NOSPLIT,$16
MOVW $0, R4 // CLOCK_REALTIME
MOVV $0(R29), R5
MOVV $SYS_clock_gettime, R2
SYSCALL
MOVV 0(R29), R3 // sec
MOVV 8(R29), R5 // nsec
MOVV R3, sec+0(FP)
MOVW R5, nsec+8(FP)
RET
TEXT runtime·nanotime(SB),NOSPLIT,$16
MOVW $1, R4 // CLOCK_MONOTONIC
MOVV $0(R29), R5
MOVV $SYS_clock_gettime, R2
SYSCALL
MOVV 0(R29), R3 // sec
MOVV 8(R29), R5 // nsec
// sec is in R3, nsec in R5
// return nsec in R3
MOVV $1000000000, R4
MULVU R4, R3
MOVV LO, R3
ADDVU R5, R3
MOVV R3, ret+0(FP)
RET
TEXT runtime·rtsigprocmask(SB),NOSPLIT,$-8-28
MOVW how+0(FP), R4
MOVV new+8(FP), R5
MOVV old+16(FP), R6
MOVW size+24(FP), R7
MOVV $SYS_rt_sigprocmask, R2
SYSCALL
BEQ R7, 2(PC)
MOVV R0, 0xf1(R0) // crash
RET
TEXT runtime·rt_sigaction(SB),NOSPLIT,$-8-36
MOVV sig+0(FP), R4
MOVV new+8(FP), R5
MOVV old+16(FP), R6
MOVV size+24(FP), R7
MOVV $SYS_rt_sigaction, R2
SYSCALL
MOVW R2, ret+32(FP)
RET
TEXT runtime·sigfwd(SB),NOSPLIT,$0-32
MOVW sig+8(FP), R4
MOVV info+16(FP), R5
MOVV ctx+24(FP), R6
MOVV fn+0(FP), R25
JAL (R25)
RET
TEXT runtime·sigtramp(SB),NOSPLIT,$64
// initialize REGSB = PC&0xffffffff00000000
BGEZAL R0, 1(PC)
SRLV $32, R31, RSB
SLLV $32, RSB
// this might be called in external code context,
// where g is not set.
MOVB runtime·iscgo(SB), R1
BEQ R1, 2(PC)
JAL runtime·load_g(SB)
MOVW R4, 8(R29)
MOVV R5, 16(R29)
MOVV R6, 24(R29)
MOVV $runtime·sigtrampgo(SB), R1
JAL (R1)
RET
TEXT runtime·cgoSigtramp(SB),NOSPLIT,$0
JMP runtime·sigtramp(SB)
TEXT runtime·mmap(SB),NOSPLIT,$-8
MOVV addr+0(FP), R4
MOVV n+8(FP), R5
MOVW prot+16(FP), R6
MOVW flags+20(FP), R7
MOVW fd+24(FP), R8
MOVW off+28(FP), R9
MOVV $SYS_mmap, R2
SYSCALL
MOVV R2, ret+32(FP)
RET
TEXT runtime·munmap(SB),NOSPLIT,$-8
MOVV addr+0(FP), R4
MOVV n+8(FP), R5
MOVV $SYS_munmap, R2
SYSCALL
BEQ R7, 2(PC)
MOVV R0, 0xf3(R0) // crash
RET
TEXT runtime·madvise(SB),NOSPLIT,$-8
MOVV addr+0(FP), R4
MOVV n+8(FP), R5
MOVW flags+16(FP), R6
MOVV $SYS_madvise, R2
SYSCALL
// ignore failure - maybe pages are locked
RET
// int64 futex(int32 *uaddr, int32 op, int32 val,
// struct timespec *timeout, int32 *uaddr2, int32 val2);
TEXT runtime·futex(SB),NOSPLIT,$-8
MOVV addr+0(FP), R4
MOVW op+8(FP), R5
MOVW val+12(FP), R6
MOVV ts+16(FP), R7
MOVV addr2+24(FP), R8
MOVW val3+32(FP), R9
MOVV $SYS_futex, R2
SYSCALL
MOVW R2, ret+40(FP)
RET
// int64 clone(int32 flags, void *stk, M *mp, G *gp, void (*fn)(void));
TEXT runtime·clone(SB),NOSPLIT,$-8
MOVW flags+0(FP), R4
MOVV stk+8(FP), R5
// Copy mp, gp, fn off parent stack for use by child.
// Careful: Linux system call clobbers ???.
MOVV mp+16(FP), R16
MOVV gp+24(FP), R17
MOVV fn+32(FP), R18
MOVV R16, -8(R5)
MOVV R17, -16(R5)
MOVV R18, -24(R5)
MOVV $1234, R16
MOVV R16, -32(R5)
MOVV $SYS_clone, R2
SYSCALL
// In parent, return.
BEQ R2, 3(PC)
MOVW R2, ret+40(FP)
RET
// In child, on new stack.
MOVV -32(R29), R16
MOVV $1234, R1
BEQ R16, R1, 2(PC)
MOVV R0, 0(R0)
// Initialize m->procid to Linux tid
MOVV $SYS_gettid, R2
SYSCALL
MOVV -24(R29), R18 // fn
MOVV -16(R29), R17 // g
MOVV -8(R29), R16 // m
BEQ R16, nog
BEQ R17, nog
MOVV R2, m_procid(R16)
// TODO: setup TLS.
// In child, set up new stack
MOVV R16, g_m(R17)
MOVV R17, g
//CALL runtime·stackcheck(SB)
nog:
// Call fn
JAL (R18)
// It shouldn't return. If it does, exit that thread.
MOVW $111, R4
MOVV $SYS_exit, R2
SYSCALL
JMP -3(PC) // keep exiting
TEXT runtime·sigaltstack(SB),NOSPLIT,$-8
MOVV new+0(FP), R4
MOVV old+8(FP), R5
MOVV $SYS_sigaltstack, R2
SYSCALL
BEQ R7, 2(PC)
MOVV R0, 0xf1(R0) // crash
RET
TEXT runtime·osyield(SB),NOSPLIT,$-8
MOVV $SYS_sched_yield, R2
SYSCALL
RET
TEXT runtime·sched_getaffinity(SB),NOSPLIT,$-8
MOVV pid+0(FP), R4
MOVV len+8(FP), R5
MOVV buf+16(FP), R6
MOVV $SYS_sched_getaffinity, R2
SYSCALL
MOVW R2, ret+24(FP)
RET
// int32 runtime·epollcreate(int32 size);
TEXT runtime·epollcreate(SB),NOSPLIT,$-8
MOVW size+0(FP), R4
MOVV $SYS_epoll_create, R2
SYSCALL
MOVW R2, ret+8(FP)
RET
// int32 runtime·epollcreate1(int32 flags);
TEXT runtime·epollcreate1(SB),NOSPLIT,$-8
MOVW flags+0(FP), R4
MOVV $SYS_epoll_create1, R2
SYSCALL
MOVW R2, ret+8(FP)
RET
// func epollctl(epfd, op, fd int32, ev *epollEvent) int
TEXT runtime·epollctl(SB),NOSPLIT,$-8
MOVW epfd+0(FP), R4
MOVW op+4(FP), R5
MOVW fd+8(FP), R6
MOVV ev+16(FP), R7
MOVV $SYS_epoll_ctl, R2
SYSCALL
MOVW R2, ret+24(FP)
RET
// int32 runtime·epollwait(int32 epfd, EpollEvent *ev, int32 nev, int32 timeout);
TEXT runtime·epollwait(SB),NOSPLIT,$-8
MOVW epfd+0(FP), R4
MOVV ev+8(FP), R5
MOVW nev+16(FP), R6
MOVW timeout+20(FP), R7
MOVV $SYS_epoll_wait, R2
SYSCALL
MOVW R2, ret+24(FP)
RET
// void runtime·closeonexec(int32 fd);
TEXT runtime·closeonexec(SB),NOSPLIT,$-8
MOVW fd+0(FP), R4 // fd
MOVV $2, R5 // F_SETFD
MOVV $1, R6 // FD_CLOEXEC
MOVV $SYS_fcntl, R2
SYSCALL
RET
// func sbrk0() uintptr
TEXT runtime·sbrk0(SB),NOSPLIT,$-8-8
// Implemented as brk(NULL).
MOVV $0, R4
MOVV $SYS_brk, R2
SYSCALL
MOVV R2, ret+0(FP)
RET