207 lines
6.7 KiB
Zig
207 lines
6.7 KiB
Zig
const builtin = @import("builtin");
|
|
|
|
// Zig's own stack-probe routine (available only on x86 and x86_64)
|
|
pub nakedcc fn zig_probe_stack() void {
|
|
@setRuntimeSafety(false);
|
|
|
|
// Versions of the Linux kernel before 5.1 treat any access below SP as
|
|
// invalid so let's update it on the go, otherwise we'll get a segfault
|
|
// instead of triggering the stack growth.
|
|
|
|
switch (builtin.arch) {
|
|
.x86_64 => {
|
|
// %rax = probe length, %rsp = stack pointer
|
|
asm volatile (
|
|
\\ push %%rcx
|
|
\\ mov %%rax, %%rcx
|
|
\\ cmp $0x1000,%%rcx
|
|
\\ jb 2f
|
|
\\ 1:
|
|
\\ sub $0x1000,%%rsp
|
|
\\ orl $0,16(%%rsp)
|
|
\\ sub $0x1000,%%rcx
|
|
\\ cmp $0x1000,%%rcx
|
|
\\ ja 1b
|
|
\\ 2:
|
|
\\ sub %%rcx, %%rsp
|
|
\\ orl $0,16(%%rsp)
|
|
\\ add %%rax,%%rsp
|
|
\\ pop %%rcx
|
|
\\ ret
|
|
);
|
|
},
|
|
.i386 => {
|
|
// %eax = probe length, %esp = stack pointer
|
|
asm volatile (
|
|
\\ push %%ecx
|
|
\\ mov %%eax, %%ecx
|
|
\\ cmp $0x1000,%%ecx
|
|
\\ jb 2f
|
|
\\ 1:
|
|
\\ sub $0x1000,%%esp
|
|
\\ orl $0,8(%%esp)
|
|
\\ sub $0x1000,%%ecx
|
|
\\ cmp $0x1000,%%ecx
|
|
\\ ja 1b
|
|
\\ 2:
|
|
\\ sub %%ecx, %%esp
|
|
\\ orl $0,8(%%esp)
|
|
\\ add %%eax,%%esp
|
|
\\ pop %%ecx
|
|
\\ ret
|
|
);
|
|
},
|
|
else => {},
|
|
}
|
|
|
|
unreachable;
|
|
}
|
|
|
|
fn win_probe_stack_only() void {
|
|
@setRuntimeSafety(false);
|
|
|
|
switch (builtin.arch) {
|
|
.x86_64 => {
|
|
asm volatile (
|
|
\\ push %%rcx
|
|
\\ push %%rax
|
|
\\ cmp $0x1000,%%rax
|
|
\\ lea 24(%%rsp),%%rcx
|
|
\\ jb 1f
|
|
\\ 2:
|
|
\\ sub $0x1000,%%rcx
|
|
\\ test %%rcx,(%%rcx)
|
|
\\ sub $0x1000,%%rax
|
|
\\ cmp $0x1000,%%rax
|
|
\\ ja 2b
|
|
\\ 1:
|
|
\\ sub %%rax,%%rcx
|
|
\\ test %%rcx,(%%rcx)
|
|
\\ pop %%rax
|
|
\\ pop %%rcx
|
|
\\ ret
|
|
);
|
|
},
|
|
.i386 => {
|
|
asm volatile (
|
|
\\ push %%ecx
|
|
\\ push %%eax
|
|
\\ cmp $0x1000,%%eax
|
|
\\ lea 12(%%esp),%%ecx
|
|
\\ jb 1f
|
|
\\ 2:
|
|
\\ sub $0x1000,%%ecx
|
|
\\ test %%ecx,(%%ecx)
|
|
\\ sub $0x1000,%%eax
|
|
\\ cmp $0x1000,%%eax
|
|
\\ ja 2b
|
|
\\ 1:
|
|
\\ sub %%eax,%%ecx
|
|
\\ test %%ecx,(%%ecx)
|
|
\\ pop %%eax
|
|
\\ pop %%ecx
|
|
\\ ret
|
|
);
|
|
},
|
|
else => {},
|
|
}
|
|
|
|
unreachable;
|
|
}
|
|
|
|
fn win_probe_stack_adjust_sp() void {
|
|
@setRuntimeSafety(false);
|
|
|
|
switch (builtin.arch) {
|
|
.x86_64 => {
|
|
asm volatile (
|
|
\\ push %%rcx
|
|
\\ cmp $0x1000,%%rax
|
|
\\ lea 16(%%rsp),%%rcx
|
|
\\ jb 1f
|
|
\\ 2:
|
|
\\ sub $0x1000,%%rcx
|
|
\\ test %%rcx,(%%rcx)
|
|
\\ sub $0x1000,%%rax
|
|
\\ cmp $0x1000,%%rax
|
|
\\ ja 2b
|
|
\\ 1:
|
|
\\ sub %%rax,%%rcx
|
|
\\ test %%rcx,(%%rcx)
|
|
\\
|
|
\\ lea 8(%%rsp),%%rax
|
|
\\ mov %%rcx,%%rsp
|
|
\\ mov -8(%%rax),%%rcx
|
|
\\ push (%%rax)
|
|
\\ sub %%rsp,%%rax
|
|
\\ ret
|
|
);
|
|
},
|
|
.i386 => {
|
|
asm volatile (
|
|
\\ push %%ecx
|
|
\\ cmp $0x1000,%%eax
|
|
\\ lea 8(%%esp),%%ecx
|
|
\\ jb 1f
|
|
\\ 2:
|
|
\\ sub $0x1000,%%ecx
|
|
\\ test %%ecx,(%%ecx)
|
|
\\ sub $0x1000,%%eax
|
|
\\ cmp $0x1000,%%eax
|
|
\\ ja 2b
|
|
\\ 1:
|
|
\\ sub %%eax,%%ecx
|
|
\\ test %%ecx,(%%ecx)
|
|
\\
|
|
\\ lea 4(%%esp),%%eax
|
|
\\ mov %%ecx,%%esp
|
|
\\ mov -4(%%eax),%%ecx
|
|
\\ push (%%eax)
|
|
\\ sub %%esp,%%eax
|
|
\\ ret
|
|
);
|
|
},
|
|
else => {},
|
|
}
|
|
|
|
unreachable;
|
|
}
|
|
|
|
// Windows has a multitude of stack-probing functions with similar names and
|
|
// slightly different behaviours: some behave as alloca() and update the stack
|
|
// pointer after probing the stack, other do not.
|
|
//
|
|
// Function name | Adjusts the SP? |
|
|
// | x86 | x86_64 |
|
|
// ----------------------------------------
|
|
// _chkstk (_alloca) | yes | yes |
|
|
// __chkstk | yes | no |
|
|
// __chkstk_ms | no | no |
|
|
// ___chkstk (__alloca) | yes | yes |
|
|
// ___chkstk_ms | no | no |
|
|
|
|
pub nakedcc fn _chkstk() void {
|
|
@setRuntimeSafety(false);
|
|
@inlineCall(win_probe_stack_adjust_sp);
|
|
}
|
|
pub nakedcc fn __chkstk() void {
|
|
@setRuntimeSafety(false);
|
|
switch (builtin.arch) {
|
|
.i386 => @inlineCall(win_probe_stack_adjust_sp),
|
|
.x86_64 => @inlineCall(win_probe_stack_only),
|
|
else => unreachable,
|
|
}
|
|
}
|
|
pub nakedcc fn ___chkstk() void {
|
|
@setRuntimeSafety(false);
|
|
@inlineCall(win_probe_stack_adjust_sp);
|
|
}
|
|
pub nakedcc fn __chkstk_ms() void {
|
|
@setRuntimeSafety(false);
|
|
@inlineCall(win_probe_stack_only);
|
|
}
|
|
pub nakedcc fn ___chkstk_ms() void {
|
|
@setRuntimeSafety(false);
|
|
@inlineCall(win_probe_stack_only);
|
|
}
|