[PATCH 1/8] tunables: Make tunable_list relro

Siddhesh Poyarekar siddhesh@sourceware.org
Wed May 10 14:47:00 GMT 2017


From: Siddhesh Poyarekar <siddhesh.poyarekar@linaro.org>

As of now we don't need tunables to be writable after they have been
set initially, so there is no point in having them writable.  Put
tunable_list in .data.rel.ro so that it is set as read-only after
relocation.  This also allows us to move some of the dl_* variables
that are tunables controlled into the tunables infrastructure instead
of having two copies.

In future if we ever need specific tunables to be writable at runtime,
we can split the tunable_list into two.

Regression tested on x86_64 to verify that tests continue to pass.

	* scripts/gen-tunables.awk: Add attribute_relro to
	tunable_list.

Change-Id: Ibb398bf3c7f1ea3c5d0a7fdd4cb794005a94b02f
---
 scripts/gen-tunables.awk | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/scripts/gen-tunables.awk b/scripts/gen-tunables.awk
index 601240a..defb3e7 100644
--- a/scripts/gen-tunables.awk
+++ b/scripts/gen-tunables.awk
@@ -141,7 +141,7 @@ END {
 
   # Finally, the tunable list.
   print "\n#ifdef TUNABLES_INTERNAL"
-  print "static tunable_t tunable_list[] = {"
+  print "static tunable_t tunable_list[] attribute_relro = {"
   for (t in types) {
     for (n in types[t]) {
       for (m in types[t][n]) {
-- 
2.9.3



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