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std: Use correct clone() stub 

The previous clone() definition was written for 32bit PPC targets,
trying to execute it on a PPC64 machine lead to countless crashes.

Use the clone() definition kindly lifted from Musl libc.
master
LemonBoy 2020-11-08 16:32:54 +01:00
parent 73be59433f
commit 4e2a4e194b
1 changed files with 49 additions and 40 deletions
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89
lib/std/special/c.zig
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@ -386,6 +386,11 @@ fn clone() callconv(.Naked) void {
);
},
.arm => {
// __clone(func, stack, flags, arg, ptid, tls, ctid)
// r0, r1, r2, r3, +0, +4, +8
// syscall(SYS_clone, flags, stack, ptid, tls, ctid)
// r7 r0, r1, r2, r3, r4
asm volatile (
\\ stmfd sp!,{r4,r5,r6,r7}
\\ mov r7,#120
@ -445,6 +450,11 @@ fn clone() callconv(.Naked) void {
);
},
.mips, .mipsel => {
// __clone(func, stack, flags, arg, ptid, tls, ctid)
// 3, 4, 5, 6, 7, 8, 9
// syscall(SYS_clone, flags, stack, ptid, tls, ctid)
// 2 4, 5, 6, 7, 8
asm volatile (
\\ # Save function pointer and argument pointer on new thread stack
\\ and $5, $5, -8
@ -465,12 +475,14 @@ fn clone() callconv(.Naked) void {
\\ addu $sp, $sp, 16
\\ jr $ra
\\ subu $2, $0, $2
\\1: beq $2, $0, 1f
\\1:
\\ beq $2, $0, 1f
\\ nop
\\ addu $sp, $sp, 16
\\ jr $ra
\\ nop
\\1: lw $25, 0($sp)
\\1:
\\ lw $25, 0($sp)
\\ lw $4, 4($sp)
\\ jalr $25
\\ nop
@ -480,51 +492,48 @@ fn clone() callconv(.Naked) void {
);
},
.powerpc64, .powerpc64le => {
// __clone(func, stack, flags, arg, ptid, tls, ctid)
// 3, 4, 5, 6, 7, 8, 9
// syscall(SYS_clone, flags, stack, ptid, tls, ctid)
// 0 3, 4, 5, 6, 7
asm volatile (
\\ # store non-volatile regs r30, r31 on stack in order to put our
\\ # start func and its arg there
\\ stwu 30, -16(1)
\\ stw 31, 4(1)
\\ # save r3 (func) into r30, and r6(arg) into r31
\\ mr 30, 3
\\ mr 31, 6
\\ # create initial stack frame for new thread
\\ clrrwi 4, 4, 4
\\ li 0, 0
\\ stwu 0, -16(4)
\\ #move c into first arg
\\ mr 3, 5
\\ mr 5, 7
\\ mr 6, 8
\\ mr 7, 9
\\ # move syscall number into r0
\\ li 0, 120
\\ clrrdi 4, 4, 4
\\ li 0, 0
\\ stdu 0,-32(4)
\\
\\ # save fn and arg to child stack
\\ std 3, 8(4)
\\ std 6, 16(4)
\\
\\ # shuffle args into correct registers and call SYS_clone
\\ mr 3, 5
\\ #mr 4, 4
\\ mr 5, 7
\\ mr 6, 8
\\ mr 7, 9
\\ li 0, 120 # SYS_clone = 120
\\ sc
\\ # check for syscall error
\\ bns+ 1f # jump to label 1 if no summary overflow.
\\ #else
\\ neg 3, 3 #negate the result (errno)
\\
\\ # if error, negate return (errno)
\\ bns+ 1f
\\ neg 3, 3
\\
\\1:
\\ # compare sc result with 0
\\ # if we're the parent, return
\\ cmpwi cr7, 3, 0
\\ # if not 0, jump to end
\\ bne cr7, 2f
\\ #else: we're the child
\\ #call funcptr: move arg (d) into r3
\\ mr 3, 31
\\ #move r30 (funcptr) into CTR reg
\\ mtctr 30
\\ # call CTR reg
\\ bnelr cr7
\\
\\ # we're the child. call fn(arg)
\\ ld 3, 16(1)
\\ ld 12, 8(1)
\\ mtctr 12
\\ bctrl
\\ # mov SYS_exit into r0 (the exit param is already in r3)
\\ li 0, 1
\\
\\ # call SYS_exit. exit code is already in r3 from fn return value
\\ li 0, 1 # SYS_exit = 1
\\ sc
\\2:
\\ # restore stack
\\ lwz 30, 0(1)
\\ lwz 31, 4(1)
\\ addi 1, 1, 16
\\ blr
);
},
.sparcv9 => {