Re: [PATCH] tunables: Add IFUNC selection and cache sizes

["H.J. Lu" <hjl dot tools at gmail dot com>]

On Wed, Jun 21, 2017 at 7:35 AM, Siddhesh Poyarekar <siddhesh@gotplt.org> wrote:
> On Wednesday 21 June 2017 06:56 PM, H.J. Lu wrote:
>> I am testing this patch.  OK for master if there are no regressions?
>>
>
> Looks OK to me with one comment change which I missed the last time:
>
>>       Since all CPU/ARCH features are hardware optimizations without
>>       security implication, except for Prefer_MAP_32BIT_EXEC, which can
>> -     only be disabled, we check GLIBC_IFUNC for programs, including
>> +     only be disabled, we check glibc.tune.hwcaps for programs, including
>>       set*id ones.
>
> This block is no longer valid since the tunables are not read for setxid
> binaries.  If you want to make a case for hwcaps to be read in setxid
> binaries, then it should be made along with hwcap_mask since they're
> essentially the same feature for different machines.
>

Here is the updated patch.  OK for master?

-- 
H.J.

From 3d6a433311d99dced1378d44b9f37736594e631f Mon Sep 17 00:00:00 2001
From: "H.J. Lu" <hjl.tools@gmail.com>
Date: Tue, 20 Jun 2017 12:09:56 -0700
Subject: [PATCH] Move x86 specific tunables to x86/dl-tunables.list

	* elf/dl-tunables.list: Move x86 specific tunables to ...
	* sysdeps/x86/dl-tunables.list: Here.  New file.
---
 elf/dl-tunables.list         | 12 ------------
 sysdeps/x86/dl-tunables.list | 34 ++++++++++++++++++++++++++++++++++
 2 files changed, 34 insertions(+), 12 deletions(-)
 create mode 100644 sysdeps/x86/dl-tunables.list

diff --git a/elf/dl-tunables.list b/elf/dl-tunables.list
index 3247d49..b8b0ce5 100644
--- a/elf/dl-tunables.list
+++ b/elf/dl-tunables.list
@@ -87,17 +87,5 @@ glibc {
       type: STRING
       security_level: SXID_IGNORE
     }
-    x86_non_temporal_threshold {
-      type: SIZE_T
-      security_level: SXID_IGNORE
-    }
-    x86_data_cache_size {
-      type: SIZE_T
-      security_level: SXID_IGNORE
-    }
-    x86_shared_cache_size {
-      type: SIZE_T
-      security_level: SXID_IGNORE
-    }
   }
 }
diff --git a/sysdeps/x86/dl-tunables.list b/sysdeps/x86/dl-tunables.list
new file mode 100644
index 0000000..50c130a
--- /dev/null
+++ b/sysdeps/x86/dl-tunables.list
@@ -0,0 +1,34 @@
+# x86 specific tunables.
+# Copyright (C) 2017 Free Software Foundation, Inc.
+# This file is part of the GNU C Library.
+
+# The GNU C Library is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Lesser General Public
+# License as published by the Free Software Foundation; either
+# version 2.1 of the License, or (at your option) any later version.
+
+# The GNU C Library is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# Lesser General Public License for more details.
+
+# You should have received a copy of the GNU Lesser General Public
+# License along with the GNU C Library; if not, see
+# <http://www.gnu.org/licenses/>.
+
+glibc {
+  tune {
+    x86_non_temporal_threshold {
+      type: SIZE_T
+      security_level: SXID_IGNORE
+    }
+    x86_data_cache_size {
+      type: SIZE_T
+      security_level: SXID_IGNORE
+    }
+    x86_shared_cache_size {
+      type: SIZE_T
+      security_level: SXID_IGNORE
+    }
+  }
+}
-- 
2.9.4