[Xen-devel] [PATCH v2 06/24] xen/arm: traps: Don't define FAR_EL2 for ARM32

[Julien Grall <julien.grall@xxxxxxx>]

Aliasing FAR_EL2 to HIFAR makes the code confusing because on ARMv8
FAR_EL2[31:0] is architecturally mapped to HDFAR and FAR_EL2[63:32] to
HIFAR. See D7.2.30 in ARM DDI 0487B.a. Open-code the alias instead.

Signed-off-by: Julien Grall <julien.grall@xxxxxxx>
Reviewed-by: Andre Przywara <andre.przywara@xxxxxxx>

---
    Changes in v2:
        - Fix register name in the commit message
        - Add Andre's reviewed-by
---
 xen/arch/arm/traps.c         | 8 +++++++-
 xen/include/asm-arm/cpregs.h | 1 -
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/xen/arch/arm/traps.c b/xen/arch/arm/traps.c
index 7f6ec15b5e..967bfea4ed 100644
--- a/xen/arch/arm/traps.c
+++ b/xen/arch/arm/traps.c
@@ -2579,11 +2579,17 @@ static void do_trap_instr_abort_guest(struct 
cpu_user_regs *regs,
                                       const union hsr hsr)
 {
     int rc;
-    register_t gva = READ_SYSREG(FAR_EL2);
+    register_t gva;
     uint8_t fsc = hsr.iabt.ifsc & ~FSC_LL_MASK;
     paddr_t gpa;
     mfn_t mfn;
 
+#ifdef CONFIG_ARM_32
+    gva = READ_CP32(HIFAR);
+#else
+    gva = READ_SYSREG64(FAR_EL2);
+#endif
+
     /*
      * If this bit has been set, it means that this instruction abort is caused
      * by a guest external abort. We can handle this instruction abort as guest
diff --git a/xen/include/asm-arm/cpregs.h b/xen/include/asm-arm/cpregs.h
index af45ec7a65..1889d7cbfb 100644
--- a/xen/include/asm-arm/cpregs.h
+++ b/xen/include/asm-arm/cpregs.h
@@ -307,7 +307,6 @@
 #define ESR_EL1                 DFSR
 #define ESR_EL2                 HSR
 #define FAR_EL1                 HIFAR
-#define FAR_EL2                 HIFAR
 #define HCR_EL2                 HCR
 #define HPFAR_EL2               HPFAR
 #define HSTR_EL2                HSTR
-- 
2.11.0


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