[for-stable-4.14,31/48] arm64: Get rid of __smccc_workaround_1_hvc_*

Message ID 20191024124833.4158-32-ard.biesheuvel@linaro.org
State New
Headers show
Series
  • arm64 spec mitigation backports
Related show

Commit Message

Ard Biesheuvel Oct. 24, 2019, 12:48 p.m.
From: Marc Zyngier <marc.zyngier@arm.com>


[ Upstream commit 22765f30dbaf1118c6ff0fcb8b99c9f2b4d396d5 ]

The very existence of __smccc_workaround_1_hvc_* is a thinko, as
KVM will never use a HVC call to perform the branch prediction
invalidation. Even as a nested hypervisor, it would use an SMC
instruction.

Let's get rid of it.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

Signed-off-by: Will Deacon <will.deacon@arm.com>

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>

---
 arch/arm64/kernel/bpi.S        | 12 ++----------
 arch/arm64/kernel/cpu_errata.c |  9 +++------
 2 files changed, 5 insertions(+), 16 deletions(-)

-- 
2.20.1

Patch

diff --git a/arch/arm64/kernel/bpi.S b/arch/arm64/kernel/bpi.S
index 0af46cfdbbf3..4cae34e5a24e 100644
--- a/arch/arm64/kernel/bpi.S
+++ b/arch/arm64/kernel/bpi.S
@@ -56,21 +56,13 @@  ENTRY(__bp_harden_hyp_vecs_start)
 ENTRY(__bp_harden_hyp_vecs_end)
 
 
-.macro smccc_workaround_1 inst
+ENTRY(__smccc_workaround_1_smc_start)
 	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
+	smc	#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 4204b668df7a..6e565d8d4f71 100644
--- a/arch/arm64/kernel/cpu_errata.c
+++ b/arch/arm64/kernel/cpu_errata.c
@@ -85,8 +85,6 @@  DEFINE_PER_CPU_READ_MOSTLY(struct bp_hardening_data, bp_hardening_data);
 #ifdef CONFIG_KVM
 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)
@@ -131,8 +129,6 @@  static void __install_bp_hardening_cb(bp_hardening_cb_t fn,
 #else
 #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,
@@ -206,8 +202,9 @@  enable_smccc_arch_workaround_1(const struct arm64_cpu_capabilities *entry)
 		if ((int)res.a0 < 0)
 			return;
 		cb = call_hvc_arch_workaround_1;
-		smccc_start = __smccc_workaround_1_hvc_start;
-		smccc_end = __smccc_workaround_1_hvc_end;
+		/* This is a guest, no need to patch KVM vectors */
+		smccc_start = NULL;
+		smccc_end = NULL;
 		break;
 
 	case PSCI_CONDUIT_SMC: