Patchwork [5/8] tunables: Add LD_HWCAP_MASK to tunables

login
register
mail settings
Submitter Siddhesh Poyarekar
Date May 10, 2017, 2:47 p.m.
Message ID <1494427637-14555-6-git-send-email-siddhesh@sourceware.org>
Download mbox | patch
Permalink /patch/20377/
State New
Headers show

Comments

Siddhesh Poyarekar - May 10, 2017, 2:47 p.m.
Add LD_HWCAP_MASK to tunables in preparation of it being removed from
rtld.c.  This allows us to read LD_HWCAP_MASK much earlier so that it
can influence IFUNC resolution in aarch64.

This patch does not actually do anything other than read the
LD_HWCAP_MASK variable and add the tunables way to set the
LD_HWCAP_MASK, i.e. via the glibc.tune.hwcap_mask tunable.  In a
follow-up patch, the _dl_hwcap_mask will be replaced with
glibc.tune.hwcap_mask to complete the transition.

	* elf/dl-tunables.list: Add glibc.tune.hwcap_mask.
	* scripts/gen-tunables.awk: Include dl-procinfo.h.
---
 elf/dl-tunables.list     | 7 +++++++
 scripts/gen-tunables.awk | 1 +
 2 files changed, 8 insertions(+)

Patch

diff --git a/elf/dl-tunables.list b/elf/dl-tunables.list
index b9f1488..41ce9af 100644
--- a/elf/dl-tunables.list
+++ b/elf/dl-tunables.list
@@ -77,4 +77,11 @@  glibc {
       security_level: SXID_IGNORE
     }
   }
+  tune {
+    hwcap_mask {
+      type: UINT_64
+      env_alias: LD_HWCAP_MASK
+      default: HWCAP_IMPORTANT
+    }
+  }
 }
diff --git a/scripts/gen-tunables.awk b/scripts/gen-tunables.awk
index b10b00e..93e5aff 100644
--- a/scripts/gen-tunables.awk
+++ b/scripts/gen-tunables.awk
@@ -134,6 +134,7 @@  END {
   print "# error \"Do not include this file directly.\""
   print "# error \"Include tunables.h instead.\""
   print "#endif"
+  print "#include <dl-procinfo.h>\n"
 
   # Now, the enum names
   print "\ntypedef enum"