Commit caa334712f
Changed files (3)
lib
std
os
linux
lib/std/os/linux/x86.zig
@@ -394,28 +394,51 @@ fn gpRegisterOffset(comptime reg_index: comptime_int) usize {
return @offsetOf(ucontext_t, "mcontext") + @offsetOf(mcontext_t, "gregs") + @sizeOf(usize) * reg_index;
}
-pub inline fn getcontext(context: *ucontext_t) usize {
+noinline fn getContextReturnAddress() usize {
+ return @returnAddress();
+}
+
+pub fn getContextInternal() callconv(.Naked) void {
asm volatile (
- \\ movl %%edi, (%[edi_offset])(%[context])
- \\ movl %%esi, (%[esi_offset])(%[context])
- \\ movl %%ebp, (%[ebp_offset])(%[context])
- \\ movl %%esp, (%[esp_offset])(%[context])
- \\ movl %%ebx, (%[ebx_offset])(%[context])
- \\ movl %%edx, (%[edx_offset])(%[context])
- \\ movl %%ecx, (%[ecx_offset])(%[context])
- \\ movl %%eax, (%[eax_offset])(%[context])
+ \\ movl $0, (%[flags_offset])(%%edx)
+ \\ movl $0, (%[link_offset])(%%edx)
+ \\ movl %%edi, (%[edi_offset])(%%edx)
+ \\ movl %%esi, (%[esi_offset])(%%edx)
+ \\ movl %%ebp, (%[ebp_offset])(%%edx)
+ \\ movl %%ebx, (%[ebx_offset])(%%edx)
+ \\ movl %%edx, (%[edx_offset])(%%edx)
+ \\ movl %%ecx, (%[ecx_offset])(%%edx)
+ \\ movl %%eax, (%[eax_offset])(%%edx)
+ \\ movl (%%esp), %%ecx
+ \\ movl %%ecx, (%[eip_offset])(%%edx)
+ \\ leal 4(%%esp), %%ecx
+ \\ movl %%ecx, (%[esp_offset])(%%edx)
\\ xorl %%ecx, %%ecx
\\ movw %%fs, %%cx
- \\ movl %%ecx, (%[fs_offset])(%[context])
- \\ leal (%[regspace_offset])(%[context]), %%ecx
- \\ movl %%ecx, (%[fpregs_offset])(%[context])
+ \\ movl %%ecx, (%[fs_offset])(%%edx)
+ \\ leal (%[regspace_offset])(%%edx), %%ecx
+ \\ movl %%ecx, (%[fpregs_offset])(%%edx)
\\ fnstenv (%%ecx)
\\ fldenv (%%ecx)
- \\ call getcontext_read_eip
- \\ getcontext_read_eip: pop %%ecx
- \\ movl %%ecx, (%[eip_offset])(%[context])
+ \\ pushl %%ebx
+ \\ pushl %%esi
+ \\ xorl %%ebx, %%ebx
+ \\ movl %[sigaltstack], %%eax
+ \\ leal (%[stack_offset])(%%edx), %%ecx
+ \\ int $0x80
+ \\ cmpl $0, %%eax
+ \\ jne return
+ \\ movl %[sigprocmask], %%eax
+ \\ xorl %%ecx, %%ecx
+ \\ leal (%[sigmask_offset])(%%edx), %%edx
+ \\ movl %[sigset_size], %%esi
+ \\ int $0x80
+ \\ return:
+ \\ popl %%esi
+ \\ popl %%ebx
:
- : [context] "{edi}" (context),
+ : [flags_offset] "p" (@offsetOf(ucontext_t, "flags")),
+ [link_offset] "p" (@offsetOf(ucontext_t, "link")),
[edi_offset] "p" (comptime gpRegisterOffset(REG.EDI)),
[esi_offset] "p" (comptime gpRegisterOffset(REG.ESI)),
[ebp_offset] "p" (comptime gpRegisterOffset(REG.EBP)),
@@ -428,18 +451,24 @@ pub inline fn getcontext(context: *ucontext_t) usize {
[fs_offset] "p" (comptime gpRegisterOffset(REG.FS)),
[fpregs_offset] "p" (@offsetOf(ucontext_t, "mcontext") + @offsetOf(mcontext_t, "fpregs")),
[regspace_offset] "p" (@offsetOf(ucontext_t, "regspace")),
- : "memory", "ecx"
+ [sigaltstack] "i" (@intFromEnum(linux.SYS.sigaltstack)),
+ [stack_offset] "p" (@offsetOf(ucontext_t, "stack")),
+ [sigprocmask] "i" (@intFromEnum(linux.SYS.rt_sigprocmask)),
+ [sigmask_offset] "p" (@offsetOf(ucontext_t, "sigmask")),
+ [sigset_size] "i" (linux.NSIG / 8),
+ : "memory", "eax", "ecx", "edx"
);
+}
- // TODO: Read CS/SS registers?
- // TODO: Store mxcsr state, need an actual definition of fpstate for that
-
- // TODO: `flags` isn't present in the getcontext man page, figure out what to write here
- context.flags = 0;
- context.link = null;
-
- const altstack_result = linux.sigaltstack(null, &context.stack);
- if (altstack_result != 0) return altstack_result;
-
- return linux.sigprocmask(0, null, &context.sigmask);
+pub inline fn getcontext(context: *ucontext_t) usize {
+ // This method is used so that getContextInternal can control
+ // its prologue in order to read ESP from a constant offset.
+ // The unused &getContextInternal input is required so the function is included in the binary.
+ return asm volatile (
+ \\ call os.linux.x86.getContextInternal
+ : [ret] "={eax}" (-> usize),
+ : [context] "{edx}" (context),
+ [getContextInternal] "X" (&getContextInternal),
+ : "memory", "ecx"
+ );
}
lib/std/os/linux/x86_64.zig
@@ -400,35 +400,53 @@ fn gpRegisterOffset(comptime reg_index: comptime_int) usize {
return @offsetOf(ucontext_t, "mcontext") + @offsetOf(mcontext_t, "gregs") + @sizeOf(usize) * reg_index;
}
-pub inline fn getcontext(context: *ucontext_t) usize {
+fn getContextInternal() callconv(.Naked) void {
+ // TODO: Read GS/FS registers?
asm volatile (
- \\ movq %%r8, (%[r8_offset])(%[context])
- \\ movq %%r9, (%[r9_offset])(%[context])
- \\ movq %%r10, (%[r10_offset])(%[context])
- \\ movq %%r11, (%[r11_offset])(%[context])
- \\ movq %%r12, (%[r12_offset])(%[context])
- \\ movq %%r13, (%[r13_offset])(%[context])
- \\ movq %%r14, (%[r14_offset])(%[context])
- \\ movq %%r15, (%[r15_offset])(%[context])
- \\ movq %%rdi, (%[rdi_offset])(%[context])
- \\ movq %%rsi, (%[rsi_offset])(%[context])
- \\ movq %%rbp, (%[rbp_offset])(%[context])
- \\ movq %%rbx, (%[rbx_offset])(%[context])
- \\ movq %%rdx, (%[rdx_offset])(%[context])
- \\ movq %%rax, (%[rax_offset])(%[context])
- \\ movq %%rcx, (%[rcx_offset])(%[context])
- \\ movq %%rsp, (%[rsp_offset])(%[context])
- \\ leaq (%%rip), %%rcx
- \\ movq %%rcx, (%[rip_offset])(%[context])
+ \\ movq $0, (%[flags_offset])(%%rdi)
+ \\ movq $0, (%[link_offset])(%%rdi)
+ \\ movq %%r8, (%[r8_offset])(%%rdi)
+ \\ movq %%r9, (%[r9_offset])(%%rdi)
+ \\ movq %%r10, (%[r10_offset])(%%rdi)
+ \\ movq %%r11, (%[r11_offset])(%%rdi)
+ \\ movq %%r12, (%[r12_offset])(%%rdi)
+ \\ movq %%r13, (%[r13_offset])(%%rdi)
+ \\ movq %%r14, (%[r14_offset])(%%rdi)
+ \\ movq %%r15, (%[r15_offset])(%%rdi)
+ \\ movq %%rdi, (%[rdi_offset])(%%rdi)
+ \\ movq %%rsi, (%[rsi_offset])(%%rdi)
+ \\ movq %%rbp, (%[rbp_offset])(%%rdi)
+ \\ movq %%rbx, (%[rbx_offset])(%%rdi)
+ \\ movq %%rdx, (%[rdx_offset])(%%rdi)
+ \\ movq %%rax, (%[rax_offset])(%%rdi)
+ \\ movq %%rcx, (%[rcx_offset])(%%rdi)
+ \\ movq (%%rsp), %%rcx
+ \\ movq %%rcx, (%[rip_offset])(%%rdi)
+ \\ leaq 8(%%rsp), %%rcx
+ \\ movq %%rcx, (%[rsp_offset])(%%rdi)
\\ pushfq
- \\ popq (%[efl_offset])(%[context])
- \\ leaq (%[fpmem_offset])(%[context]), %%rcx
- \\ movq %%rcx, (%[fpstate_offset])(%[context])
+ \\ popq (%[efl_offset])(%%rdi)
+ \\ leaq (%[fpmem_offset])(%%rdi), %%rcx
+ \\ movq %%rcx, (%[fpstate_offset])(%%rdi)
\\ fnstenv (%%rcx)
\\ fldenv (%%rcx)
- \\ stmxcsr (%[mxcsr_offset])(%[context])
+ \\ stmxcsr (%[mxcsr_offset])(%%rdi)
+ \\ leaq (%[stack_offset])(%%rdi), %%rsi
+ \\ movq %%rdi, %%r8
+ \\ xorq %%rdi, %%rdi
+ \\ movq %[sigaltstack], %%rax
+ \\ syscall
+ \\ cmpq $0, %%rax
+ \\ jne return
+ \\ movq %[sigprocmask], %%rax
+ \\ xorq %%rsi, %%rsi
+ \\ leaq (%[sigmask_offset])(%%r8), %%rdx
+ \\ movq %[sigset_size], %%r10
+ \\ syscall
+ \\ return:
:
- : [context] "{rdi}" (context),
+ : [flags_offset] "p" (@offsetOf(ucontext_t, "flags")),
+ [link_offset] "p" (@offsetOf(ucontext_t, "link")),
[r8_offset] "p" (comptime gpRegisterOffset(REG.R8)),
[r9_offset] "p" (comptime gpRegisterOffset(REG.R9)),
[r10_offset] "p" (comptime gpRegisterOffset(REG.R10)),
@@ -450,17 +468,24 @@ pub inline fn getcontext(context: *ucontext_t) usize {
[fpstate_offset] "p" (@offsetOf(ucontext_t, "mcontext") + @offsetOf(mcontext_t, "fpregs")),
[fpmem_offset] "p" (@offsetOf(ucontext_t, "fpregs_mem")),
[mxcsr_offset] "p" (@offsetOf(ucontext_t, "fpregs_mem") + @offsetOf(fpstate, "mxcsr")),
- : "memory", "rcx"
+ [sigaltstack] "i" (@intFromEnum(linux.SYS.sigaltstack)),
+ [stack_offset] "p" (@offsetOf(ucontext_t, "stack")),
+ [sigprocmask] "i" (@intFromEnum(linux.SYS.rt_sigprocmask)),
+ [sigmask_offset] "p" (@offsetOf(ucontext_t, "sigmask")),
+ [sigset_size] "i" (linux.NSIG / 8),
+ : "memory", "rcx", "rdx", "rdi", "rsi", "r8", "r10", "r11"
);
+}
- // TODO: Read GS/FS registers?
-
- // TODO: `flags` isn't present in the getcontext man page, figure out what to write here
- context.flags = 0;
- context.link = null;
-
- const altstack_result = linux.sigaltstack(null, &context.stack);
- if (altstack_result != 0) return altstack_result;
-
- return linux.sigprocmask(0, null, &context.sigmask);
+pub inline fn getcontext(context: *ucontext_t) usize {
+ // This method is used so that getContextInternal can control
+ // its prologue in order to read RSP from a constant offset
+ // The unused &getContextInternal input is required so the function is included in the binary.
+ return asm volatile (
+ \\ call os.linux.x86_64.getContextInternal
+ : [ret] "={rax}" (-> usize),
+ : [context] "{rdi}" (context),
+ [getContextInternal] "X" (&getContextInternal),
+ : "memory", "rcx", "rdx", "rdi", "rsi", "r8", "r10", "r11"
+ );
}
lib/std/debug.zig
@@ -136,7 +136,7 @@ pub fn dumpCurrentStackTrace(start_addr: ?usize) void {
pub const StackTraceContext = blk: {
if (native_os == .windows) {
break :blk std.os.windows.CONTEXT;
- } else if (@hasDecl(os.system, "ucontext_t")) {
+ } else if (StackIterator.supports_context) {
break :blk os.ucontext_t;
} else {
break :blk void;