From 5d0fdb245bbb1dd4d7cc94eae91981ff79c4852d Mon Sep 17 00:00:00 2001
From: Giulio Benetti <giulio.benetti@benettiengineering.com>
Date: Sat, 7 Mar 2020 23:47:09 +0100
Subject: [PATCH] Bug 1620799 - Introduce NSS_DISABLE_GCM_ARM32_NEON

Only some Arm32 supports neon, so let's introduce
NSS_DISABLE_GCM_ARM32_NEON to allow disabling gcm-arm32-neon.c building.

Signed-off-by: Giulio Benetti <giulio.benetti@benettiengineering.com>
---
 nss/coreconf/config.gypi  |  1 +
 nss/coreconf/config.mk    |  5 +++++
 nss/lib/freebl/Makefile   |  4 ++++
 nss/lib/freebl/freebl.gyp | 14 ++++++++++++--
 nss/lib/freebl/gcm.c      |  3 ++-
 5 files changed, 24 insertions(+), 3 deletions(-)

diff --git a/nss/coreconf/config.gypi b/nss/coreconf/config.gypi
index 2a730398b..2a7fe8ac0 100644
--- a/nss/coreconf/config.gypi
+++ b/nss/coreconf/config.gypi
@@ -103,6 +103,7 @@
     'disable_libpkix%': 1,
     'disable_werror%': 0,
     'disable_altivec%': 0,
+    'disable_gcm_arm32_neon%': 0,
     'mozilla_client%': 0,
     'comm_client%': 0,
     'moz_fold_libs%': 0,
diff --git a/nss/coreconf/config.mk b/nss/coreconf/config.mk
index 704e3fa83..9042e78bf 100644
--- a/nss/coreconf/config.mk
+++ b/nss/coreconf/config.mk
@@ -196,6 +196,11 @@ DEFINES += -DPKIX_OBJECT_LEAK_TEST
 endif
 endif
 
+# Avoid building gcm-arm32-neon.c
+ifdef NSS_DISABLE_GCM_ARM32_NEON
+DEFINES += -DNSS_DISABLE_GCM_ARM32_NEON
+endif
+
 # Avoid building with PowerPC's Altivec acceleration
 ifdef NSS_DISABLE_ALTIVEC
 DEFINES += -DNSS_DISABLE_ALTIVEC
diff --git a/nss/lib/freebl/Makefile b/nss/lib/freebl/Makefile
index ce9d36f3a..2802fdf42 100644
--- a/nss/lib/freebl/Makefile
+++ b/nss/lib/freebl/Makefile
@@ -124,7 +124,9 @@ ifeq ($(CPU_ARCH),aarch64)
     EXTRA_SRCS += aes-armv8.c gcm-aarch64.c
 endif
 ifeq ($(CPU_ARCH),arm)
+ifndef NSS_DISABLE_GCM_ARM32_NEON
     EXTRA_SRCS += gcm-arm32-neon.c
+endif
     ifdef CC_IS_CLANG
         DEFINES += -DUSE_HW_AES
         EXTRA_SRCS += aes-armv8.c
@@ -770,8 +772,10 @@ ifeq ($(CPU_ARCH),arm)
 # Confusingly, __SOFTFP__ is the name of the define for the softfloat ABI, not for the softfp ABI.
 USES_SOFTFLOAT_ABI := $(shell $(CC) -o - -E -dM - $(CFLAGS) < /dev/null | grep __SOFTFP__ > /dev/null && echo 1)
 $(OBJDIR)/$(PROG_PREFIX)aes-armv8$(OBJ_SUFFIX): CFLAGS += -march=armv8-a -mfpu=crypto-neon-fp-armv8$(if $(USES_SOFTFLOAT_ABI), -mfloat-abi=softfp)
+ifndef NSS_DISABLE_GCM_ARM32_NEON
 $(OBJDIR)/$(PROG_PREFIX)gcm-arm32-neon$(OBJ_SUFFIX): CFLAGS += -march=armv7 -mfpu=neon$(if $(USES_SOFTFLOAT_ABI), -mfloat-abi=softfp)
 endif
+endif
 ifeq ($(CPU_ARCH),aarch64)
 $(OBJDIR)/$(PROG_PREFIX)aes-armv8$(OBJ_SUFFIX): CFLAGS += -march=armv8-a+crypto
 $(OBJDIR)/$(PROG_PREFIX)gcm-aarch64$(OBJ_SUFFIX): CFLAGS += -march=armv8-a+crypto
diff --git a/nss/lib/freebl/freebl.gyp b/nss/lib/freebl/freebl.gyp
index d46bd1949..7bf4e9f7e 100644
--- a/nss/lib/freebl/freebl.gyp
+++ b/nss/lib/freebl/freebl.gyp
@@ -265,11 +265,16 @@
             'armv8_c_lib'
           ],
         }],
-        [ 'target_arch=="arm"', {
+        [ 'disable_gcm_arm32_neon==0 and target_arch=="arm"', {
           'dependencies': [
             'gcm-aes-arm32-neon_c_lib',
           ],
         }],
+        [ 'disable_gcm_arm32_neon==1 and target_arch=="arm"', {
+          'defines!': [
+            'NSS_DISABLE_GCM_ARM32_NEON',
+          ],
+        }],
         [ 'target_arch=="arm64" or target_arch=="aarch64"', {
           'dependencies': [
             'gcm-aes-aarch64_c_lib',
@@ -326,11 +331,16 @@
             'armv8_c_lib',
           ],
         }],
-        [ 'target_arch=="arm"', {
+        [ 'disable_gcm_arm32_neon==0 and target_arch=="arm"', {
           'dependencies': [
             'gcm-aes-arm32-neon_c_lib',
           ],
         }],
+        [ 'disable_gcm_arm32_neon==1 and target_arch=="arm"', {
+          'defines!': [
+            'NSS_DISABLE_GCM_ARM32_NEON',
+          ],
+        }],
         [ 'target_arch=="arm64" or target_arch=="aarch64"', {
           'dependencies': [
             'gcm-aes-aarch64_c_lib',
diff --git a/nss/lib/freebl/gcm.c b/nss/lib/freebl/gcm.c
index 2a42f74c0..9b1c6c02f 100644
--- a/nss/lib/freebl/gcm.c
+++ b/nss/lib/freebl/gcm.c
@@ -21,7 +21,8 @@
 #if defined(__aarch64__) && defined(IS_LITTLE_ENDIAN) && \
     (defined(__clang__) || defined(__GNUC__) && __GNUC__ > 6)
 #define USE_ARM_GCM
-#elif defined(__arm__) && defined(IS_LITTLE_ENDIAN)
+#elif defined(__arm__) && defined(IS_LITTLE_ENDIAN) && \
+      !defined(NSS_DISABLE_GCM_ARM32_NEON)
 /* We don't test on big endian platform, so disable this on big endian. */
 #define USE_ARM_GCM
 #endif
-- 
2.20.1