[v4.4,V2,12/43] arm64: cpufeature: Test 'matches' pointer to find the end of the list

Message ID 64c9f2c29cd2e63aecbd233aa96fd9d18e165330.1562908075.git.viresh.kumar@linaro.org
State New
Headers show
Series
  • V4.4 backport of arm64 Spectre patches
Related show

Commit Message

Viresh Kumar July 12, 2019, 5:28 a.m.
From: James Morse <james.morse@arm.com>


commit 644c2ae198412c956700e55a2acf80b2541f6aa5 upstream.

CPU feature code uses the desc field as a test to find the end of the list,
this means every entry must have a description. This generates noise for
entries in the list that aren't really features, but combinations of them.
e.g.
> CPU features: detected feature: Privileged Access Never

> CPU features: detected feature: PAN and not UAO


These combination features are needed for corner cases with alternatives,
where cpu features interact.

Change all walkers of the arm64_features[] and arm64_hwcaps[] lists to test
'matches' not 'desc', and only print 'desc' if it is non-NULL.

Signed-off-by: James Morse <james.morse@arm.com>

Reviewed-by : Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

---
 arch/arm64/kernel/cpufeature.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

-- 
2.21.0.rc0.269.g1a574e7a288b

Patch

diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index c1eddc07d996..bdb4cd9ffccf 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -744,7 +744,7 @@  static void setup_cpu_hwcaps(void)
 	int i;
 	const struct arm64_cpu_capabilities *hwcaps = arm64_hwcaps;
 
-	for (i = 0; hwcaps[i].desc; i++)
+	for (i = 0; hwcaps[i].matches; i++)
 		if (hwcaps[i].matches(&hwcaps[i]))
 			cap_set_hwcap(&hwcaps[i]);
 }
@@ -754,11 +754,11 @@  void update_cpu_capabilities(const struct arm64_cpu_capabilities *caps,
 {
 	int i;
 
-	for (i = 0; caps[i].desc; i++) {
+	for (i = 0; caps[i].matches; i++) {
 		if (!caps[i].matches(&caps[i]))
 			continue;
 
-		if (!cpus_have_cap(caps[i].capability))
+		if (!cpus_have_cap(caps[i].capability) && caps[i].desc)
 			pr_info("%s %s\n", info, caps[i].desc);
 		cpus_set_cap(caps[i].capability);
 	}
@@ -772,7 +772,7 @@  static void enable_cpu_capabilities(const struct arm64_cpu_capabilities *caps)
 {
 	int i;
 
-	for (i = 0; caps[i].desc; i++)
+	for (i = 0; caps[i].matches; i++)
 		if (caps[i].enable && cpus_have_cap(caps[i].capability))
 			/*
 			 * Use stop_machine() as it schedules the work allowing
@@ -884,7 +884,7 @@  void verify_local_cpu_capabilities(void)
 		return;
 
 	caps = arm64_features;
-	for (i = 0; caps[i].desc; i++) {
+	for (i = 0; caps[i].matches; i++) {
 		if (!cpus_have_cap(caps[i].capability) || !caps[i].sys_reg)
 			continue;
 		/*
@@ -897,7 +897,7 @@  void verify_local_cpu_capabilities(void)
 			caps[i].enable(NULL);
 	}
 
-	for (i = 0, caps = arm64_hwcaps; caps[i].desc; i++) {
+	for (i = 0, caps = arm64_hwcaps; caps[i].matches; i++) {
 		if (!cpus_have_hwcap(&caps[i]))
 			continue;
 		if (!feature_matches(__raw_read_system_reg(caps[i].sys_reg), &caps[i]))