From: Niels Möller <nisse@lysator.liu.se>
Date: Sun, 14 Aug 2022 18:53:10 +0000 (+0200)
Subject: Workaround for qemu bug affecting the ppc intruction vmsumudm
X-Git-Tag: nettle_3.9_release_20230514~82
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d618864183ccfdcd0d1b5443111fbaf9a5934517;p=thirdparty%2Fnettle.git

Workaround for qemu bug affecting the ppc intruction vmsumudm

Introduce overriding environment variable NETTLE_FAT_DISABLE_POWER9
that disables use of power9 code. This makes poly1305 tests under qemu
pass. See https://gitlab.com/qemu-project/qemu/-/issues/1156.
---

diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index ed15456f..b206873e 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -158,8 +158,8 @@ Debian.cross.x86:
   - ./.bootstrap
   - ./configure --disable-static --disable-documentation $EXTRA_CONFIGURE_FLAGS --build=$build --host=$host
   - make -j$(nproc)
-  - NETTLE_TEST_SEED=0 make -j$(nproc) check
-  - NETTLE_TEST_SEED=0 make -j$(nproc) check-fat
+  - NETTLE_TEST_SEED=0 NETTLE_FAT_DISABLE_POWER9=1 make -j$(nproc) check
+  - NETTLE_TEST_SEED=0 NETTLE_FAT_DISABLE_POWER9=1 make -j$(nproc) check-fat
   tags:
   - shared
   - linux
diff --git a/fat-ppc.c b/fat-ppc.c
index 7569e44d..b0412e5a 100644
--- a/fat-ppc.c
+++ b/fat-ppc.c
@@ -153,6 +153,11 @@ get_ppc_features (struct ppc_features *features)
 	   == (PPC_FEATURE_HAS_ALTIVEC | PPC_FEATURE_HAS_VSX));
 #endif
     }
+  /* NETTLE_FAT_DISABLE_POWER9 can be set to disable code that fails
+     in qemu, due to
+     https://gitlab.com/qemu-project/qemu/-/issues/1156. */
+  if (secure_getenv (ENV_DISABLE_POWER9))
+    features->have_power9 = 0;
 }
 
 DECLARE_FAT_FUNC(_nettle_aes_encrypt, aes_crypt_internal_func)
diff --git a/fat-setup.h b/fat-setup.h
index ad3c10f0..a35b8b8c 100644
--- a/fat-setup.h
+++ b/fat-setup.h
@@ -92,6 +92,7 @@
 
 #define ENV_VERBOSE "NETTLE_FAT_VERBOSE"
 #define ENV_OVERRIDE "NETTLE_FAT_OVERRIDE"
+#define ENV_DISABLE_POWER9 "NETTLE_FAT_DISABLE_POWER9"
 
 struct chacha_ctx;
 struct salsa20_ctx;