ppc64le: support OPENSSL_ppccap ENV variable

aws · May 14, 2024 · 5678e02 · 5678e02
1 parent e3c4f7d
commit 5678e02
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Showing 2 changed files with 47 additions and 2 deletions.
diff --git a/crypto/fipsmodule/cpucap/cpu_intel.c b/crypto/fipsmodule/cpucap/cpu_intel.c
@@ -137,9 +137,9 @@ static void handle_cpu_env(uint32_t *out, const char *in) {
   int sscanf_result;
   uint64_t v;
   if (hex) {
-    sscanf_result = sscanf(in + invert + 2, "%" PRIx64, &v);
+    sscanf_result = sscanf(in + skip_first_byte + 2, "%" PRIx64, &v);
   } else {
-    sscanf_result = sscanf(in + invert, "%" PRIu64, &v);
+    sscanf_result = sscanf(in + skip_first_byte, "%" PRIu64, &v);
   }
 
   if (!sscanf_result) {

diff --git a/crypto/fipsmodule/cpucap/cpu_ppc64le.c b/crypto/fipsmodule/cpucap/cpu_ppc64le.c
@@ -24,11 +24,56 @@
 #define PPC_FEATURE2_HAS_VCRYPTO 0x02000000
 #endif
 
+static void handle_cpu_env(unsigned long *out, const char *in) {
+  OPENSSL_STATIC_ASSERT(sizeof(unsigned long) == 8, PPC64LE_UNSIGNED_LONG_NOT_8_BYTES);
+
+  const int invert = in[0] == '~';
+  const int or = in[0] == '|';
+  const int skip_first_byte = (invert || or) ? 1 : 0;
+  const int hex = in[skip_first_byte] == '0' && in[skip_first_byte+1] == 'x';
+
+  int sscanf_result;
+  uint64_t v;
+  if (hex) {
+    sscanf_result = sscanf(in + skip_first_byte + 2, "%" PRIx64, &v);
+  } else {
+    sscanf_result = sscanf(in + skip_first_byte, "%" PRIu64, &v);
+  }
+
+  if (!sscanf_result) {
+    return;
+  }
+
+  if (invert) {
+    *out &= ~v;
+  } else if (or) {
+    *out |= v;
+  } else {
+    *out = v;
+  }
+}
+
 extern uint8_t OPENSSL_cpucap_initialized;
 
 void OPENSSL_cpuid_setup(void) {
   OPENSSL_ppc64le_hwcap2 = getauxval(AT_HWCAP2);
   OPENSSL_cpucap_initialized = 1;
+
+  // OPENSSL_ppccap is a 64-bit hex string which may start with "0x".
+  // Prior to the value, a '~' or '|' may be given.
+  //
+  // If the '~' prefix is present:
+  //   the value is inverted and ANDed with the probed CPUID result
+  // If the '|' prefix is present:
+  //   the value is ORed with the probed CPUID result
+  // Otherwise:
+  //   the value is taken as the result of the CPUID
+  const char *env;
+  env = getenv("OPENSSL_ppccap");
+  if (env != NULL) {
+    handle_cpu_env(&OPENSSL_ppc64le_hwcap2, env);
+  }
+
 }
 
 int CRYPTO_is_PPC64LE_vcrypto_capable(void) {