From 8aa3833db97e8fe1143c5ece110b9321ce1494ea Mon Sep 17 00:00:00 2001
From: Bertrand Marquis <bertrand.marquis@arm.com>
Date: Wed, 23 Feb 2022 09:42:18 +0000
Subject: xen/arm: Add ECBHB and CLEARBHB ID fields

Introduce ID coprocessor register ID_AA64ISAR2_EL1.
Add definitions in cpufeature and sysregs of ECBHB field in mmfr1 and
CLEARBHB in isar2 ID coprocessor registers.

This is part of XSA-398 / CVE-2022-23960.

Signed-off-by: Bertrand Marquis <bertrand.marquis@arm.com>
Acked-by: Julien Grall <julien@xen.org>
(cherry picked from commit 4b68d12d98b8790d8002fcc2c25a9d713374a4d7)

diff --git a/xen/arch/arm/cpufeature.c b/xen/arch/arm/cpufeature.c
index 6e51f530a80e..a58965f7b9bf 100644
--- a/xen/arch/arm/cpufeature.c
+++ b/xen/arch/arm/cpufeature.c
@@ -122,6 +122,7 @@ void identify_cpu(struct cpuinfo_arm *c)
 
     c->isa64.bits[0] = READ_SYSREG(ID_AA64ISAR0_EL1);
     c->isa64.bits[1] = READ_SYSREG(ID_AA64ISAR1_EL1);
+    c->isa64.bits[2] = READ_SYSREG(ID_AA64ISAR2_EL1);
 
     c->zfr64.bits[0] = READ_SYSREG(ID_AA64ZFR0_EL1);
 
diff --git a/xen/include/asm-arm/arm64/sysregs.h b/xen/include/asm-arm/arm64/sysregs.h
index d7e4772f217f..eac08ed33f53 100644
--- a/xen/include/asm-arm/arm64/sysregs.h
+++ b/xen/include/asm-arm/arm64/sysregs.h
@@ -84,6 +84,9 @@
 #ifndef ID_DFR1_EL1
 #define ID_DFR1_EL1                 S3_0_C0_C3_5
 #endif
+#ifndef ID_AA64ISAR2_EL1
+#define ID_AA64ISAR2_EL1            S3_0_C0_C6_2
+#endif
 
 /* ID registers (imported from arm64/include/asm/sysreg.h in Linux) */
 
@@ -139,6 +142,9 @@
 #define ID_AA64ISAR1_GPI_NI                     0x0
 #define ID_AA64ISAR1_GPI_IMP_DEF                0x1
 
+/* id_aa64isar2 */
+#define ID_AA64ISAR2_CLEARBHB_SHIFT 28
+
 /* id_aa64pfr0 */
 #define ID_AA64PFR0_CSV3_SHIFT       60
 #define ID_AA64PFR0_CSV2_SHIFT       56
@@ -232,6 +238,7 @@
 #define ID_AA64MMFR0_PARANGE_52        0x6
 
 /* id_aa64mmfr1 */
+#define ID_AA64MMFR1_ECBHB_SHIFT     60
 #define ID_AA64MMFR1_ETS_SHIFT       36
 #define ID_AA64MMFR1_TWED_SHIFT      32
 #define ID_AA64MMFR1_XNX_SHIFT       28
diff --git a/xen/include/asm-arm/cpufeature.h b/xen/include/asm-arm/cpufeature.h
index 8a5afbaf0baf..db126508f159 100644
--- a/xen/include/asm-arm/cpufeature.h
+++ b/xen/include/asm-arm/cpufeature.h
@@ -243,14 +243,15 @@ struct cpuinfo_arm {
             unsigned long lo:4;
             unsigned long pan:4;
             unsigned long __res1:8;
-            unsigned long __res2:32;
+            unsigned long __res2:28;
+            unsigned long ecbhb:4;
 
             unsigned long __res3:64;
         };
     } mm64;
 
     union {
-        register_t bits[2];
+        register_t bits[3];
         struct {
             /* ISAR0 */
             unsigned long __res0:4;
@@ -286,6 +287,12 @@ struct cpuinfo_arm {
             unsigned long dgh:4;
             unsigned long i8mm:4;
             unsigned long __res2:8;
+
+            /* ISAR2 */
+            unsigned long __res3:28;
+            unsigned long clearbhb:4;
+
+            unsigned long __res4:32;
         };
     } isa64;