[meta-virtualization][gatesgarth][PATCH 2/3] xen: drop patch to workaround prelink on aarch64

[Christopher Clark <christopher.w.clark@gmail.com>]

Patch is not needed for image prelinking since the gcc toolchain
in this branch successfully links Xen without it.

Remove the patch from the stable branch since the BSD license of the
modified header file differs vs the GPLv2 source code referenced.
Removal preferred to replacement with a new patch that moves the function
into GPLv2 .c source files since the build now succeeds without it.

Signed-off-by: Christopher Clark <christopher.w.clark@gmail.com>
---
 ...xen-arm64-implement-atomic-fetch-add.patch | 50 -------------------
 recipes-extended/xen/xen_4.14.bb              |  1 -
 recipes-extended/xen/xen_git.bb               |  1 -
 3 files changed, 52 deletions(-)
 delete mode 100644 recipes-extended/xen/files/xen-arm64-implement-atomic-fetch-add.patch

diff --git a/recipes-extended/xen/files/xen-arm64-implement-atomic-fetch-add.patch b/recipes-extended/xen/files/xen-arm64-implement-atomic-fetch-add.patch
deleted file mode 100644
index 6e957a5..0000000
--- a/recipes-extended/xen/files/xen-arm64-implement-atomic-fetch-add.patch
+++ /dev/null
@@ -1,50 +0,0 @@
-From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
-From: Christopher Clark <christopher.w.clark@gmail.com>
-Date: Fri, 26 June 2020 16:34:00 -0800
-Subject: [PATCH] xen: implement atomic op to fix arm64 compilation
-
-Xen's ARM implementation of arch_fetch_and_add since f9cc3cd9
-uses a builtin, despite the build being performed with -fno-builtin.
-With gcc 10.1.0, this now breaks prelinking spinlock.c, so
-implement the one atomic operation that is required with logic
-derived from Linux's atomic_ll_sc.h: ATOMIC_FETCH_OP and comparison with
-the binary produced with and without the patch with gcc 9.2.0.
-
-Signed-off-by: Christopher Clark <christopher.w.clark@gmail.com>
-diff --git a/xen/include/asm-arm/system.h b/xen/include/asm-arm/system.h
-index e5d062667d..c46dd3ac71 100644
---- a/xen/include/asm-arm/system.h
-+++ b/xen/include/asm-arm/system.h
-@@ -55,7 +55,32 @@ static inline int local_abort_is_enabled(void)
-     return !(flags & PSR_ABT_MASK);
- }
- 
-+#ifdef CONFIG_ARM_64
-+
-+/* see atomic_ll_sc.h:  ATOMIC_FETCH_OP(name, mb, acq, rel, cl, op, asm_op, constraint) */
-+static inline int arch_fetch_and_add(unsigned int *ptr, unsigned long i)
-+{
-+    int register lptr asm("x0");
-+    int register result asm("w1");
-+    int register newval asm("w2");
-+    int register status asm("w3");
-+
-+    asm volatile(
-+    "   mov       %[lptr], %[ptr]\n"
-+    "1: ldxr      %w[result], [%[lptr]]\n"
-+    "   add       %w[newval], %w[result], %w[i]\n"
-+    "   stlxr     %w[status], %w[newval], [%[lptr]]\n"
-+    "   cbnz      %w[status], 1b\n"
-+    "   dmb       ish\n"
-+    : [result] "=&r" (result), [lptr] "=&r" (lptr), [newval] "=&r" (newval), [status] "=&r" (status), [i] "+r" (i), "+Q" (*ptr)
-+    : [ptr] "r" (ptr), "r" (i)
-+    : "memory");
-+
-+    return result;
-+}
-+#else
- #define arch_fetch_and_add(x, v) __sync_fetch_and_add(x, v)
-+#endif
- 
- extern struct vcpu *__context_switch(struct vcpu *prev, struct vcpu *next);
- 
diff --git a/recipes-extended/xen/xen_4.14.bb b/recipes-extended/xen/xen_4.14.bb
index 653e3b6..6ac3236 100644
--- a/recipes-extended/xen/xen_4.14.bb
+++ b/recipes-extended/xen/xen_4.14.bb
@@ -5,7 +5,6 @@ XEN_BRANCH ?= "stable-${XEN_REL}"
 
 SRC_URI = " \
     git://xenbits.xen.org/xen.git;branch=${XEN_BRANCH} \
-    file://xen-arm64-implement-atomic-fetch-add.patch \
     file://0001-menuconfig-mconf-cfg-Allow-specification-of-ncurses-location.patch \
     "
 
diff --git a/recipes-extended/xen/xen_git.bb b/recipes-extended/xen/xen_git.bb
index 2b62c5c..fba12e5 100644
--- a/recipes-extended/xen/xen_git.bb
+++ b/recipes-extended/xen/xen_git.bb
@@ -5,7 +5,6 @@ XEN_BRANCH ?= "master"
 
 SRC_URI = " \
     git://xenbits.xen.org/xen.git;branch=${XEN_BRANCH} \
-    file://xen-arm64-implement-atomic-fetch-add.patch \
     file://0001-menuconfig-mconf-cfg-Allow-specification-of-ncurses-location.patch \
     "
 
-- 
2.25.1