From c40c8f7d15cce87c280598c738537f67e6563198 Mon Sep 17 00:00:00 2001 From: Brendan Shanks Date: Fri, 28 Aug 2020 11:12:02 -0700 Subject: [PATCH] Use NtCurrentTeb() in GetStackStart() to fix 64-bit Wine on macOS When running 64-bit Windows binaries on macOS using Wine, there is a conflict between macOS's use of GS to point to pthread thread-specific data, and Windows' use of GS to point to the TEB. Apple has reserved some TSD slots for use by Wine to store commonly-used TEB members (such as 0x30, the 'Self' pointer to the TEB). But, other direct GS accesses by Windows programs (such as to 'StackBase') will return macOS pthread data rather than the TEB member. This was causing a V8 unit test to crash on macOS under Wine. Using NtCurrentTeb() gets the 'Self' pointer first, then dereferences it to access the correct 'StackBase', fixing the crash. This turns GetStackStart() from one instruction into two. Chrome (http://crrev.com/c/2380425) and Crashpad also use NtCurrentTeb(). The 32-bit change isn't needed, but is just for consistency. Bug: chromium:1121842 Change-Id: I824f893aa451d8570142226be91840c964426f38 Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2381941 Reviewed-by: Ulan Degenbaev Commit-Queue: Ulan Degenbaev Cr-Commit-Position: refs/heads/master@{#69627} --- AUTHORS | 1 + src/base/platform/platform-win32.cc | 6 ++++-- 2 files changed, 5 insertions(+), 2 deletions(-) diff --git a/AUTHORS b/AUTHORS index d6dd895cc7..e6822933df 100644 --- a/AUTHORS +++ b/AUTHORS @@ -40,6 +40,7 @@ Groupon <*@groupon.com> Meteor Development Group <*@meteor.com> Cloudflare, Inc. <*@cloudflare.com> Julia Computing, Inc. <*@juliacomputing.com> +CodeWeavers, Inc. <*@codeweavers.com> Aaron Bieber Aaron O'Mullan diff --git a/src/base/platform/platform-win32.cc b/src/base/platform/platform-win32.cc index 5db3e34310..6821ca9102 100644 --- a/src/base/platform/platform-win32.cc +++ b/src/base/platform/platform-win32.cc @@ -1397,9 +1397,11 @@ void OS::AdjustSchedulingParams() {} // static void* Stack::GetStackStart() { #if defined(V8_TARGET_ARCH_X64) - return reinterpret_cast(__readgsqword(offsetof(NT_TIB64, StackBase))); + return reinterpret_cast( + reinterpret_cast(NtCurrentTeb())->StackBase); #elif defined(V8_TARGET_ARCH_32_BIT) - return reinterpret_cast(__readfsdword(offsetof(NT_TIB, StackBase))); + return reinterpret_cast( + reinterpret_cast(NtCurrentTeb())->StackBase); #elif defined(V8_TARGET_ARCH_ARM64) // Windows 8 and later, see // https://docs.microsoft.com/en-us/windows/win32/api/processthreadsapi/nf-processthreadsapi-getcurrentthreadstacklimits