mirror of
https://github.com/ziglang/zig.git
synced 2026-02-13 04:48:20 +00:00
Implement stack probes for x86/x86_64
Enabled on non-Windows systems only since it already requires stack probes.
This commit is contained in:
LemonBoy
Andrew Kelley
parent
24ee765318
commit
be7cacfbbe
@ -644,6 +644,7 @@ set(ZIG_STD_FILES
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"special/build_runner.zig"
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"special/builtin.zig"
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"special/compiler_rt.zig"
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"special/compiler_rt/stack_probe.zig"
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"special/compiler_rt/arm/aeabi_fcmp.zig"
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"special/compiler_rt/arm/aeabi_dcmp.zig"
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"special/compiler_rt/addXf3.zig"
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@ -399,6 +399,15 @@ static void add_uwtable_attr(CodeGen *g, LLVMValueRef fn_val) {
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}
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}
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static void add_probe_stack_attr(CodeGen *g, LLVMValueRef fn_val) {
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// Windows already emits its own stack probes
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if (g->zig_target->os != OsWindows &&
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(g->zig_target->arch == ZigLLVM_x86 ||
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g->zig_target->arch == ZigLLVM_x86_64)) {
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addLLVMFnAttrStr(fn_val, "probe-stack", "__zig_probe_stack");
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}
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}
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static LLVMLinkage to_llvm_linkage(GlobalLinkageId id) {
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switch (id) {
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case GlobalLinkageIdInternal:
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@ -587,6 +596,8 @@ static LLVMValueRef fn_llvm_value(CodeGen *g, ZigFn *fn_table_entry) {
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addLLVMFnAttr(fn_table_entry->llvm_value, "sspstrong");
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addLLVMFnAttrStr(fn_table_entry->llvm_value, "stack-protector-buffer-size", "4");
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}
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add_probe_stack_attr(g, fn_table_entry->llvm_value);
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}
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} else {
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maybe_import_dll(g, fn_table_entry->llvm_value, linkage);
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@ -18,6 +18,12 @@
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#include <stdio.h>
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// Define this symbol here so that we can link with the zig objects during the
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// compiler bootstrap phase
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extern "C" {
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void __zig_probe_stack(void) { }
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}
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static int print_error_usage(const char *arg0) {
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fprintf(stderr, "See `%s --help` for detailed usage information\n", arg0);
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return EXIT_FAILURE;
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@ -1,10 +1,17 @@
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const builtin = @import("builtin");
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const is_test = builtin.is_test;
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const stack_probe = @import("compiler_rt/stack_probe.zig");
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comptime {
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const linkage = if (is_test) builtin.GlobalLinkage.Internal else builtin.GlobalLinkage.Weak;
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const strong_linkage = if (is_test) builtin.GlobalLinkage.Internal else builtin.GlobalLinkage.Strong;
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switch (builtin.arch) {
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.i386, .x86_64 => @export("__zig_probe_stack", @import("compiler_rt/stack_probe.zig").zig_probe_stack, linkage),
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else => { }
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}
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@export("__lesf2", @import("compiler_rt/comparesf2.zig").__lesf2, linkage);
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@export("__ledf2", @import("compiler_rt/comparedf2.zig").__ledf2, linkage);
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@export("__letf2", @import("compiler_rt/comparetf2.zig").__letf2, linkage);
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@ -191,20 +198,20 @@ comptime {
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@export("__aeabi_dcmpun", @import("compiler_rt/comparedf2.zig").__unorddf2, linkage);
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}
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if (builtin.os == builtin.Os.windows) {
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if (!builtin.link_libc) {
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@export("_chkstk", @import("compiler_rt/stack_probe.zig")._chkstk, strong_linkage);
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@export("__chkstk", @import("compiler_rt/stack_probe.zig").__chkstk, strong_linkage);
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@export("___chkstk", @import("compiler_rt/stack_probe.zig").___chkstk, strong_linkage);
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@export("__chkstk_ms", @import("compiler_rt/stack_probe.zig").__chkstk_ms, strong_linkage);
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@export("___chkstk_ms", @import("compiler_rt/stack_probe.zig").___chkstk_ms, strong_linkage);
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}
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switch (builtin.arch) {
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builtin.Arch.i386 => {
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if (!builtin.link_libc) {
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@export("_chkstk", _chkstk, strong_linkage);
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@export("__chkstk_ms", __chkstk_ms, linkage);
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}
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@export("_aulldiv", @import("compiler_rt/aulldiv.zig")._aulldiv, strong_linkage);
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@export("_aullrem", @import("compiler_rt/aullrem.zig")._aullrem, strong_linkage);
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},
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builtin.Arch.x86_64 => {
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if (!builtin.link_libc) {
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@export("__chkstk", __chkstk, strong_linkage);
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@export("___chkstk_ms", ___chkstk_ms, linkage);
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}
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// The "ti" functions must use @Vector(2, u64) parameter types to adhere to the ABI
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// that LLVM expects compiler-rt to have.
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@export("__divti3", @import("compiler_rt/divti3.zig").__divti3_windows_x86_64, linkage);
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@ -492,108 +499,6 @@ nakedcc fn __aeabi_memcmp() noreturn {
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unreachable;
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}
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// _chkstk (_alloca) routine - probe stack between %esp and (%esp-%eax) in 4k increments,
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// then decrement %esp by %eax. Preserves all registers except %esp and flags.
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// This routine is windows specific
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// http://msdn.microsoft.com/en-us/library/ms648426.aspx
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nakedcc fn _chkstk() align(4) void {
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@setRuntimeSafety(false);
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asm volatile (
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\\ push %%ecx
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\\ push %%eax
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\\ cmp $0x1000,%%eax
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\\ lea 12(%%esp),%%ecx
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\\ jb 1f
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\\ 2:
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\\ sub $0x1000,%%ecx
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\\ test %%ecx,(%%ecx)
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\\ sub $0x1000,%%eax
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\\ cmp $0x1000,%%eax
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\\ ja 2b
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\\ 1:
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\\ sub %%eax,%%ecx
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\\ test %%ecx,(%%ecx)
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\\ pop %%eax
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\\ pop %%ecx
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\\ ret
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);
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}
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nakedcc fn __chkstk() align(4) void {
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@setRuntimeSafety(false);
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asm volatile (
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\\ push %%rcx
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\\ push %%rax
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\\ cmp $0x1000,%%rax
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\\ lea 24(%%rsp),%%rcx
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\\ jb 1f
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\\2:
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\\ sub $0x1000,%%rcx
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\\ test %%rcx,(%%rcx)
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\\ sub $0x1000,%%rax
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\\ cmp $0x1000,%%rax
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\\ ja 2b
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\\1:
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\\ sub %%rax,%%rcx
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\\ test %%rcx,(%%rcx)
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\\ pop %%rax
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\\ pop %%rcx
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\\ ret
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);
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}
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// _chkstk routine
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// This routine is windows specific
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// http://msdn.microsoft.com/en-us/library/ms648426.aspx
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nakedcc fn __chkstk_ms() align(4) void {
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@setRuntimeSafety(false);
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asm volatile (
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\\ push %%ecx
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\\ push %%eax
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\\ cmp $0x1000,%%eax
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\\ lea 12(%%esp),%%ecx
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\\ jb 1f
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\\ 2:
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\\ sub $0x1000,%%ecx
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\\ test %%ecx,(%%ecx)
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\\ sub $0x1000,%%eax
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\\ cmp $0x1000,%%eax
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\\ ja 2b
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\\ 1:
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\\ sub %%eax,%%ecx
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\\ test %%ecx,(%%ecx)
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\\ pop %%eax
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\\ pop %%ecx
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\\ ret
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);
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}
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nakedcc fn ___chkstk_ms() align(4) void {
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@setRuntimeSafety(false);
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asm volatile (
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\\ push %%rcx
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\\ push %%rax
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\\ cmp $0x1000,%%rax
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\\ lea 24(%%rsp),%%rcx
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\\ jb 1f
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\\2:
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\\ sub $0x1000,%%rcx
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\\ test %%rcx,(%%rcx)
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\\ sub $0x1000,%%rax
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\\ cmp $0x1000,%%rax
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\\ ja 2b
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\\1:
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\\ sub %%rax,%%rcx
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\\ test %%rcx,(%%rcx)
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\\ pop %%rax
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\\ pop %%rcx
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\\ ret
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);
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}
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extern fn __divmodsi4(a: i32, b: i32, rem: *i32) i32 {
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@setRuntimeSafety(is_test);
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206
std/special/compiler_rt/stack_probe.zig
Normal file
206
std/special/compiler_rt/stack_probe.zig
Normal file
@ -0,0 +1,206 @@
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const builtin = @import("builtin");
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// Zig's own stack-probe routine (available only on x86 and x86_64)
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pub nakedcc fn zig_probe_stack() void {
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@setRuntimeSafety(false);
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// Versions of the Linux kernel before 5.1 treat any access below SP as
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// invalid so let's update it on the go, otherwise we'll get a segfault
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// instead of triggering the stack growth.
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switch (builtin.arch) {
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.x86_64 => {
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// %rax = probe length, %rsp = stack pointer
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asm volatile (
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\\ push %%rcx
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\\ mov %%rax, %%rcx
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\\ cmp $0x1000,%%rcx
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\\ jb 2f
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\\ 1:
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\\ sub $0x1000,%%rsp
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\\ orl $0,16(%%rsp)
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\\ sub $0x1000,%%rcx
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\\ cmp $0x1000,%%rcx
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\\ ja 1b
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\\ 2:
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\\ sub %%rcx, %%rsp
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\\ orl $0,16(%%rsp)
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\\ add %%rax,%%rsp
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\\ pop %%rcx
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\\ ret
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);
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},
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.i386 => {
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// %eax = probe length, %esp = stack pointer
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asm volatile (
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\\ push %%ecx
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\\ mov %%eax, %%ecx
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\\ cmp $0x1000,%%ecx
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\\ jb 2f
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\\ 1:
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\\ sub $0x1000,%%esp
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\\ orl $0,8(%%esp)
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\\ sub $0x1000,%%ecx
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\\ cmp $0x1000,%%ecx
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\\ ja 1b
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\\ 2:
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\\ sub %%ecx, %%esp
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\\ orl $0,8(%%esp)
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\\ add %%eax,%%esp
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\\ pop %%ecx
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\\ ret
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);
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},
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else => { }
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}
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unreachable;
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}
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fn win_probe_stack_only() void {
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@setRuntimeSafety(false);
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switch (builtin.arch) {
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.x86_64 => {
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asm volatile (
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\\ push %%rcx
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\\ push %%rax
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\\ cmp $0x1000,%%rax
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\\ lea 24(%%rsp),%%rcx
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\\ jb 1f
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\\ 2:
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\\ sub $0x1000,%%rcx
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\\ test %%rcx,(%%rcx)
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\\ sub $0x1000,%%rax
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\\ cmp $0x1000,%%rax
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\\ ja 2b
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\\ 1:
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\\ sub %%rax,%%rcx
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\\ test %%rcx,(%%rcx)
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\\ pop %%rax
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\\ pop %%rcx
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\\ ret
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);
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},
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.i386 => {
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asm volatile (
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\\ push %%ecx
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\\ push %%eax
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\\ cmp $0x1000,%%eax
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\\ lea 12(%%esp),%%ecx
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\\ jb 1f
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\\ 2:
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\\ sub $0x1000,%%ecx
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\\ test %%ecx,(%%ecx)
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\\ sub $0x1000,%%eax
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\\ cmp $0x1000,%%eax
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\\ ja 2b
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\\ 1:
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\\ sub %%eax,%%ecx
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\\ test %%ecx,(%%ecx)
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\\ pop %%eax
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\\ pop %%ecx
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\\ ret
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);
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},
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else => { }
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}
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unreachable;
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}
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fn win_probe_stack_adjust_sp() void {
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@setRuntimeSafety(false);
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switch (builtin.arch) {
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.x86_64 => {
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asm volatile (
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\\ push %%rcx
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\\ cmp $0x1000,%%rax
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\\ lea 16(%%rsp),%%rcx
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\\ jb 1f
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\\ 2:
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\\ sub $0x1000,%%rcx
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\\ test %%rcx,(%%rcx)
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\\ sub $0x1000,%%rax
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\\ cmp $0x1000,%%rax
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\\ ja 2b
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\\ 1:
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\\ sub %%rax,%%rcx
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\\ test %%rcx,(%%rcx)
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\\
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\\ lea 8(%%rsp),%%rax
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\\ mov %%rcx,%%rsp
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\\ mov -8(%%rax),%%rcx
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\\ push (%%rax)
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\\ sub %%rsp,%%rax
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\\ ret
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);
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},
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.i386 => {
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asm volatile (
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\\ push %%ecx
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\\ cmp $0x1000,%%eax
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\\ lea 8(%%esp),%%ecx
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\\ jb 1f
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\\ 2:
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\\ sub $0x1000,%%ecx
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\\ test %%ecx,(%%ecx)
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\\ sub $0x1000,%%eax
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\\ cmp $0x1000,%%eax
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\\ ja 2b
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\\ 1:
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\\ sub %%eax,%%ecx
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\\ test %%ecx,(%%ecx)
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\\
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\\ lea 4(%%esp),%%eax
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\\ mov %%ecx,%%esp
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\\ mov -4(%%eax),%%ecx
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\\ push (%%eax)
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\\ sub %%esp,%%eax
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\\ ret
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);
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},
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else => { },
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}
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unreachable;
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}
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// Windows has a multitude of stack-probing functions with similar names and
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// slightly different behaviours: some behave as alloca() and update the stack
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// pointer after probing the stack, other do not.
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//
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// Function name | Adjusts the SP? |
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// | x86 | x86_64 |
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// ----------------------------------------
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// _chkstk (_alloca) | yes | yes |
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// __chkstk | yes | no |
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// __chkstk_ms | no | no |
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// ___chkstk (__alloca) | yes | yes |
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// ___chkstk_ms | no | no |
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pub nakedcc fn _chkstk() void {
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@setRuntimeSafety(false);
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@inlineCall(win_probe_stack_adjust_sp);
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}
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pub nakedcc fn __chkstk() void {
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@setRuntimeSafety(false);
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switch (builtin.arch) {
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.i386 => @inlineCall(win_probe_stack_adjust_sp),
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.x86_64 => @inlineCall(win_probe_stack_only),
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else => unreachable
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}
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}
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pub nakedcc fn ___chkstk() void {
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@setRuntimeSafety(false);
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@inlineCall(win_probe_stack_adjust_sp);
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}
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pub nakedcc fn __chkstk_ms() void {
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@setRuntimeSafety(false);
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@inlineCall(win_probe_stack_only);
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}
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pub nakedcc fn ___chkstk_ms() void {
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@setRuntimeSafety(false);
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@inlineCall(win_probe_stack_only);
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}
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