linux-kernel - [PATCH v5 2/7] arm64: Introduce cpu_die

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <1456223505-2955-3-git-send-email-suzuki.poulose@arm.com>
Date:	Tue, 23 Feb 2016 10:31:40 +0000
From:	Suzuki K Poulose <suzuki.poulose@....com>
To:	catalin.marinas@....com
Cc:	will.deacon@....com, mark.rutland@....com,
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
	Suzuki K Poulose <suzuki.poulose@....com>
Subject: [PATCH v5 2/7] arm64: Introduce cpu_die_early

Or in other words, make fail_incapable_cpu() reusable.

We use fail_incapable_cpu() to kill a secondary CPU early during the
bringup, which doesn't have the system advertised capabilities.
This patch makes the routine more generic, to kill a secondary
booting CPU, getting rid of the dependency on capability struct.
This can be used by checks which are not necessarily attached to
a capability struct (e.g, cpu ASIDBits).

In that process, renames the function to cpu_die_early() to better
match its functionality. This will be moved to arch/arm64/kernel/smp.c
later.

Cc: Mark Rutland <mark.rutland@....com>
Cc: Catalin Marinas <catalin.marinas@....com>
Acked-by: Will Deacon <will.deacon@....com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@....com>
---
 arch/arm64/kernel/cpufeature.c |   24 +++++++++++++++---------
 1 file changed, 15 insertions(+), 9 deletions(-)

diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index cc4a089..8275e7d 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -827,15 +827,15 @@ static u64 __raw_read_system_reg(u32 sys_id)
 }
 
 /*
- * Park the CPU which doesn't have the capability as advertised
- * by the system.
+ * Kill the calling secondary CPU, early in bringup before it is turned
+ * online.
  */
-static void fail_incapable_cpu(char *cap_type,
-				 const struct arm64_cpu_capabilities *cap)
+void cpu_die_early(void)
 {
 	int cpu = smp_processor_id();
 
-	pr_crit("CPU%d: missing %s : %s\n", cpu, cap_type, cap->desc);
+	pr_crit("CPU%d: will not boot\n", cpu);
+
 	/* Mark this CPU absent */
 	set_cpu_present(cpu, 0);
 
@@ -873,8 +873,11 @@ void verify_local_cpu_capabilities(void)
 		 * If the new CPU misses an advertised feature, we cannot proceed
 		 * further, park the cpu.
 		 */
-		if (!feature_matches(__raw_read_system_reg(caps[i].sys_reg), &caps[i]))
-			fail_incapable_cpu("arm64_features", &caps[i]);
+		if (!feature_matches(__raw_read_system_reg(caps[i].sys_reg), &caps[i])) {
+			pr_crit("CPU%d: missing feature: %s\n",
+					smp_processor_id(), caps[i].desc);
+			cpu_die_early();
+		}
 		if (caps[i].enable)
 			caps[i].enable(NULL);
 	}
@@ -882,8 +885,11 @@ void verify_local_cpu_capabilities(void)
 	for (i = 0, caps = arm64_hwcaps; caps[i].desc; i++) {
 		if (!cpus_have_hwcap(&caps[i]))
 			continue;
-		if (!feature_matches(__raw_read_system_reg(caps[i].sys_reg), &caps[i]))
-			fail_incapable_cpu("arm64_hwcaps", &caps[i]);
+		if (!feature_matches(__raw_read_system_reg(caps[i].sys_reg), &caps[i])) {
+			pr_crit("CPU%d: missing HWCAP: %s\n",
+					smp_processor_id(), caps[i].desc);
+			cpu_die_early();
+		}
 	}
 }
 
-- 
1.7.9.5