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[PATCH] PR21166: Validate rdrand/rdseed support separately in gdb.reverse/insn-reverse-x86.c
- From: Luis Machado <lgustavo at codesourcery dot com>
- To: <gdb-patches at sourceware dot org>, <palves at redhat dot com>, <qiyaoltc at gmail dot com>
- Date: Thu, 23 Feb 2017 13:29:01 -0600
- Subject: [PATCH] PR21166: Validate rdrand/rdseed support separately in gdb.reverse/insn-reverse-x86.c
- Authentication-results: sourceware.org; auth=none
As reported in PR21166, there are Intel processors out there that support
rdrand but not rdseed. The fix is to verify both features separately and only
run rdrand/rdseed tests if supported.
Pedro, could you please confirm this fixes what you see in your Fedora box?
2017-02-23 Luis Machado <lgustavo@codesourcery.com>
* gdb.reverse/insn-reverse.x86.c (check_rdrand_support): Renamed to ...
(check_supported_features): ... this. Changed return type to void.
(supports_rdseed): New static global.
(rdseed): Check supports_rdseed.
(initialize): Call check_supported_features.
---
gdb/testsuite/gdb.reverse/insn-reverse-x86.c | 36 +++++++++++++++++++++-------
1 file changed, 27 insertions(+), 9 deletions(-)
diff --git a/gdb/testsuite/gdb.reverse/insn-reverse-x86.c b/gdb/testsuite/gdb.reverse/insn-reverse-x86.c
index 7f87392..85b169d 100644
--- a/gdb/testsuite/gdb.reverse/insn-reverse-x86.c
+++ b/gdb/testsuite/gdb.reverse/insn-reverse-x86.c
@@ -18,20 +18,38 @@
#include <cpuid.h>
#include <stdint.h>
-/* 0 if the CPU supports rdrand/rdseed and non-zero otherwise. */
+/* 0 if the CPU supports rdrand and non-zero otherwise. */
static unsigned int supports_rdrand;
-/* Returns non-zero if rdrand/rdseed instructions are supported and
- zero otherwise. */
+/* 0 if the CPU supports rdseed and non-zero otherwise. */
+static unsigned int supports_rdseed;
-static unsigned int
-check_rdrand_support (void)
+/* Check supported features and set globals accordingly. The globals
+ can be used to prevent unsupported tests from running. */
+
+static void
+check_supported_features (void)
{
unsigned int rdrand_mask = (1 << 30);
+ unsigned int rdseed_mask = (1 << 18);
unsigned int eax, ebx, ecx, edx;
+ unsigned int vendor;
+ unsigned int max_level;
+
+ max_level = __get_cpuid_max (0, &vendor);
+
+ if (max_level < 1)
+ return;
+
+ __cpuid (1, eax, ebx, ecx, edx);
- __get_cpuid (1, &eax, &ebx, &ecx, &edx);
- return ((ecx & rdrand_mask) == rdrand_mask);
+ supports_rdrand = ((ecx & rdrand_mask) == rdrand_mask);
+
+ if (max_level >= 7)
+ {
+ __cpuid_count (7, 0, eax, ebx, ecx, edx);
+ supports_rdseed = ((ebx & rdseed_mask) == rdseed_mask);
+ }
}
/* Test rdrand support for various output registers. */
@@ -147,7 +165,7 @@ rdseed (void)
/* Get a random seed from the rdseed assembly instruction. */
register long seed;
- if (!supports_rdrand)
+ if (!supports_rdseed)
return;
/* 16-bit random seeds. */
@@ -250,7 +268,7 @@ static void
initialize (void)
{
/* Initialize supported features. */
- supports_rdrand = check_rdrand_support ();
+ check_supported_features ();
}
/* Functions testing instruction decodings. GDB will test all of these. */
--
2.7.4