From cda79fee2afd422c2836f8ef3039fda144b05218 Mon Sep 17 00:00:00 2001
From: Julien Grall <jgrall@amazon.com>
Date: Tue, 24 Jan 2023 19:26:09 +0000
Subject: xen/arm32: flushtlb: Reduce scope of barrier for local TLB flush

Per G5-9224 in ARM DDI 0487I.a:

"A DSB NSH is sufficient to ensure completion of TLB maintenance
 instructions that apply to a single PE. A DSB ISH is sufficient to
 ensure completion of TLB maintenance instructions that apply to PEs
 in the same Inner Shareable domain.
"

This is quoting the Armv8 specification because I couldn't find an
explicit statement in the Armv7 specification. Instead, I could find
bits in various places that confirm the same implementation.

Furthermore, Linux has been using 'nsh' since 2013 (62cbbc42e001
"ARM: tlb: reduce scope of barrier domains for TLB invalidation").

This means barrier after local TLB flushes could be reduced to
non-shareable.

Signed-off-by: Julien Grall <jgrall@amazon.com>
Reviewed-by: Michal Orzel <michal.orzel@amd.com>
Tested-by: Henry Wang <Henry.Wang@arm.com>
(cherry picked from commit d56c70b6e1fe2b4ee836ca4449a3277cbbeb0ddc)

xen/arm: Remove stray semicolon at VREG_REG_HELPERS/TLB_HELPER* callers

This is inconsistent with the rest of the code where macros are used
to define functions, as it results in an empty declaration (i.e.
semicolon with nothing before it) after function definition. This is also
not allowed by C99.

Take the opportunity to undefine TLB_HELPER* macros after last use.

Signed-off-by: Michal Orzel <michal.orzel@amd.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
(cherry picked from commit 6044b485ba5b0e4073a773402cedc2f2fae540ad)

diff --git a/xen/arch/arm/include/asm/arm32/flushtlb.h b/xen/arch/arm/include/asm/arm32/flushtlb.h
index 9085e6501153..22ee3b317b4d 100644
--- a/xen/arch/arm/include/asm/arm32/flushtlb.h
+++ b/xen/arch/arm/include/asm/arm32/flushtlb.h
@@ -15,30 +15,35 @@
  * For the Stage-2 page-tables the ISB ensures the completion of the DSB
  * (and therefore the TLB invalidation) before continuing. So we know
  * the TLBs cannot contain an entry for a mapping we may have removed.
+ *
+ * Note that for local TLB flush, using non-shareable (nsh) is sufficient
+ * (see G5-9224 in ARM DDI 0487I.a).
  */
-#define TLB_HELPER(name, tlbop) \
-static inline void name(void)   \
-{                               \
-    dsb(ishst);                 \
-    WRITE_CP32(0, tlbop);       \
-    dsb(ish);                   \
-    isb();                      \
+#define TLB_HELPER(name, tlbop, sh) \
+static inline void name(void)       \
+{                                   \
+    dsb(sh ## st);                  \
+    WRITE_CP32(0, tlbop);           \
+    dsb(sh);                        \
+    isb();                          \
 }
 
 /* Flush local TLBs, current VMID only */
-TLB_HELPER(flush_guest_tlb_local, TLBIALL);
+TLB_HELPER(flush_guest_tlb_local, TLBIALL, nsh)
 
 /* Flush inner shareable TLBs, current VMID only */
-TLB_HELPER(flush_guest_tlb, TLBIALLIS);
+TLB_HELPER(flush_guest_tlb, TLBIALLIS, ish)
 
 /* Flush local TLBs, all VMIDs, non-hypervisor mode */
-TLB_HELPER(flush_all_guests_tlb_local, TLBIALLNSNH);
+TLB_HELPER(flush_all_guests_tlb_local, TLBIALLNSNH, nsh)
 
 /* Flush innershareable TLBs, all VMIDs, non-hypervisor mode */
-TLB_HELPER(flush_all_guests_tlb, TLBIALLNSNHIS);
+TLB_HELPER(flush_all_guests_tlb, TLBIALLNSNHIS, ish)
 
 /* Flush all hypervisor mappings from the TLB of the local processor. */
-TLB_HELPER(flush_xen_tlb_local, TLBIALLH);
+TLB_HELPER(flush_xen_tlb_local, TLBIALLH, nsh)
+
+#undef TLB_HELPER
 
 /* Flush TLB of local processor for address va. */
 static inline void __flush_xen_tlb_one_local(vaddr_t va)