From: Marc Zyngier <marc.zyngier@xxxxxxx>
commit b092201e0020614127f495c092e0a12d26a2116e upstream.
Add the detection and runtime code for ARM_SMCCC_ARCH_WORKAROUND_1.
It is lovely. Really.
Tested-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
Signed-off-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Signed-off-by: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
---
arch/arm64/kernel/bpi.S | 20 ++++++++++
arch/arm64/kernel/cpu_errata.c | 68 +++++++++++++++++++++++++++++++++-
2 files changed, 87 insertions(+), 1 deletion(-)
diff --git a/arch/arm64/kernel/bpi.S b/arch/arm64/kernel/bpi.S
index dec95bd82e31..c72f261f4b64 100644
--- a/arch/arm64/kernel/bpi.S
+++ b/arch/arm64/kernel/bpi.S
@@ -17,6 +17,7 @@
*/
#include <linux/linkage.h>
+#include <linux/arm-smccc.h>
.macro ventry target
.rept 31
@@ -77,3 +78,22 @@ ENTRY(__psci_hyp_bp_inval_start)
ldp x0, x1, [sp, #(16 * 8)]
add sp, sp, #(8 * 18)
ENTRY(__psci_hyp_bp_inval_end)
+
+.macro smccc_workaround_1 inst
+ sub sp, sp, #(8 * 4)
+ stp x2, x3, [sp, #(8 * 0)]
+ stp x0, x1, [sp, #(8 * 2)]
+ mov w0, #ARM_SMCCC_ARCH_WORKAROUND_1
+ \inst #0
+ ldp x2, x3, [sp, #(8 * 0)]
+ ldp x0, x1, [sp, #(8 * 2)]
+ add sp, sp, #(8 * 4)
+.endm
+
+ENTRY(__smccc_workaround_1_smc_start)
+ smccc_workaround_1 smc
+ENTRY(__smccc_workaround_1_smc_end)
+
+ENTRY(__smccc_workaround_1_hvc_start)
+ smccc_workaround_1 hvc
+ENTRY(__smccc_workaround_1_hvc_end)
diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c
index da861bf24780..506b339b91bb 100644
--- a/arch/arm64/kernel/cpu_errata.c
+++ b/arch/arm64/kernel/cpu_errata.c
@@ -51,6 +51,10 @@ DEFINE_PER_CPU_READ_MOSTLY(struct bp_hardening_data, bp_hardening_data);
#ifdef CONFIG_KVM
extern char __psci_hyp_bp_inval_start[], __psci_hyp_bp_inval_end[];
+extern char __smccc_workaround_1_smc_start[];
+extern char __smccc_workaround_1_smc_end[];
+extern char __smccc_workaround_1_hvc_start[];
+extern char __smccc_workaround_1_hvc_end[];
static void __copy_hyp_vect_bpi(int slot, const char *hyp_vecs_start,
const char *hyp_vecs_end)
@@ -95,6 +99,10 @@ static void __install_bp_hardening_cb(bp_hardening_cb_t fn,
#else
#define __psci_hyp_bp_inval_start NULL
#define __psci_hyp_bp_inval_end NULL
+#define __smccc_workaround_1_smc_start NULL
+#define __smccc_workaround_1_smc_end NULL
+#define __smccc_workaround_1_hvc_start NULL
+#define __smccc_workaround_1_hvc_end NULL
static void __install_bp_hardening_cb(bp_hardening_cb_t fn,
const char *hyp_vecs_start,
@@ -121,17 +129,75 @@ static void install_bp_hardening_cb(const struct arm64_cpu_capabilities *entry,
__install_bp_hardening_cb(fn, hyp_vecs_start, hyp_vecs_end);
}
+#include <uapi/linux/psci.h>
+#include <linux/arm-smccc.h>
#include <linux/psci.h>
+static void call_smc_arch_workaround_1(void)
+{
+ arm_smccc_1_1_smc(ARM_SMCCC_ARCH_WORKAROUND_1, NULL);
+}
+
+static void call_hvc_arch_workaround_1(void)
+{
+ arm_smccc_1_1_hvc(ARM_SMCCC_ARCH_WORKAROUND_1, NULL);
+}
+
+static bool check_smccc_arch_workaround_1(const struct arm64_cpu_capabilities *entry)
+{
+ bp_hardening_cb_t cb;
+ void *smccc_start, *smccc_end;
+ struct arm_smccc_res res;
+
+ if (!entry->matches(entry, SCOPE_LOCAL_CPU))
+ return false;
+
+ if (psci_ops.smccc_version == SMCCC_VERSION_1_0)
+ return false;
+
+ switch (psci_ops.conduit) {
+ case PSCI_CONDUIT_HVC:
+ arm_smccc_1_1_hvc(ARM_SMCCC_ARCH_FEATURES_FUNC_ID,
+ ARM_SMCCC_ARCH_WORKAROUND_1, &res);
+ if (res.a0)
+ return false;
+ cb = call_hvc_arch_workaround_1;
+ smccc_start = __smccc_workaround_1_hvc_start;
+ smccc_end = __smccc_workaround_1_hvc_end;
+ break;
+
+ case PSCI_CONDUIT_SMC:
+ arm_smccc_1_1_smc(ARM_SMCCC_ARCH_FEATURES_FUNC_ID,
+ ARM_SMCCC_ARCH_WORKAROUND_1, &res);
+ if (res.a0)
+ return false;
+ cb = call_smc_arch_workaround_1;
+ smccc_start = __smccc_workaround_1_smc_start;
+ smccc_end = __smccc_workaround_1_smc_end;
+ break;
+
+ default:
+ return false;
+ }
+
+ install_bp_hardening_cb(entry, cb, smccc_start, smccc_end);
+
+ return true;
+}
+
static int enable_psci_bp_hardening(void *data)
{
const struct arm64_cpu_capabilities *entry = data;
- if (psci_ops.get_version)
+ if (psci_ops.get_version) {
+ if (check_smccc_arch_workaround_1(entry))
+ return 0;
+
install_bp_hardening_cb(entry,
(bp_hardening_cb_t)psci_ops.get_version,
__psci_hyp_bp_inval_start,
__psci_hyp_bp_inval_end);
+ }
return 0;
}
--
2.21.0.rc0.269.g1a574e7a288b
