Turn off AVX2 lazy parsing if there is no PCLMUL.

Seemingly there are some obscure Chinese x86 CPUs that support
AVX2 and not PCLMUL, even though the former came out years
after the latter. Our AVX2 path had assumed (128-bit) PCLMUL
was available and would crash on such CPUs. Thus, check for
the correct CPUID flag (which we add support for) and go back
to the SSE2 path if so.

Fixed: 413722108
Change-Id: If4af8b408d380ada41d058e6af5bf57adbf1ad2b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6494806
Commit-Queue: Steinar H Gunderson <[email protected]>
Reviewed-by: Nico Weber <[email protected]>
Reviewed-by: Anders Hartvoll Ruud <[email protected]>
Cr-Commit-Position: refs/heads/main@{#1458810}


CrOS-Libchrome-Original-Commit: abf09a01b4ceaf11d2d4d27d078e0ede589eb627

Author: Steinar H. Gunderson

base/cpu.cc

@@ -235,6 +235,7 @@ void CPU::Initialize() {
     }
 
     has_pku_ = (cpu_info7[2] & 0x00000010) != 0;
+    has_pclmul_ = (cpu_info[2] & 0x00000002) != 0;
   }
 
   // Get the brand string of the cpu.

base/cpu.h

@@ -94,6 +94,9 @@ class BASE_EXPORT CPU final {
   bool has_avx512_f() const { return has_avx512_f_; }
   bool has_avx512_bw() const { return has_avx512_bw_; }
   bool has_avx512_vnni() const { return has_avx512_vnni_; }
+  // NOTE: This does not include 256-bit PCLMUL, which is
+  // a separate feature flag.
+  bool has_pclmul() const { return has_pclmul_; }
 #endif
   bool has_aesni() const { return has_aesni_; }
   bool has_non_stop_time_stamp_counter() const {
@@ -149,6 +152,7 @@ class BASE_EXPORT CPU final {
   bool has_avx512_f_ = false;
   bool has_avx512_bw_ = false;
   bool has_avx512_vnni_ = false;
+  bool has_pclmul_ = false;
 #endif
   bool has_aesni_ = false;
 #if defined(ARCH_CPU_ARM_FAMILY)