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[Xen-devel,v3,09/13] xen/arm64: Add generic assembly macros

Message ID 20180612113643.32020-10-julien.grall@arm.com
State New
Headers show
Series xen/arm: SSBD (aka Spectre-v4) mitigation (XSA-263) | expand

Commit Message

Julien Grall June 12, 2018, 11:36 a.m. UTC 
Add assembly macros to simplify assembly code:
    - adr_cpu_info: Get the address to the current cpu_info structure
    - ldr_this_cpu: Load a per-cpu value

This is part of XSA-263.

Signed-off-by: Julien Grall <julien.grall@arm.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>

---
    Changes in v2:
        - Add Stefano's reviewed-by
---
 xen/include/asm-arm/arm64/macros.h | 25 +++++++++++++++++++++++++
 xen/include/asm-arm/macros.h       |  2 +-
 2 files changed, 26 insertions(+), 1 deletion(-)
 create mode 100644 xen/include/asm-arm/arm64/macros.h
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Patch

diff --git a/xen/include/asm-arm/arm64/macros.h b/xen/include/asm-arm/arm64/macros.h
new file mode 100644
index 0000000000..9c5e676b37
--- /dev/null
+++ b/xen/include/asm-arm/arm64/macros.h
@@ -0,0 +1,25 @@ 
+#ifndef __ASM_ARM_ARM64_MACROS_H
+#define __ASM_ARM_ARM64_MACROS_H
+
+    /*
+     * @dst: Result of get_cpu_info()
+     */
+    .macro  adr_cpu_info, dst
+    add     \dst, sp, #STACK_SIZE
+    and     \dst, \dst, #~(STACK_SIZE - 1)
+    sub     \dst, \dst, #CPUINFO_sizeof
+    .endm
+
+    /*
+     * @dst: Result of READ_ONCE(per_cpu(sym, smp_processor_id()))
+     * @sym: The name of the per-cpu variable
+     * @tmp: scratch register
+     */
+    .macro  ldr_this_cpu, dst, sym, tmp
+    ldr     \dst, =per_cpu__\sym
+    mrs     \tmp, tpidr_el2
+    ldr     \dst, [\dst, \tmp]
+    .endm
+
+#endif /* __ASM_ARM_ARM64_MACROS_H */
+
diff --git a/xen/include/asm-arm/macros.h b/xen/include/asm-arm/macros.h
index 5d837cb38b..1d4bb41d15 100644
--- a/xen/include/asm-arm/macros.h
+++ b/xen/include/asm-arm/macros.h
@@ -8,7 +8,7 @@ 
 #if defined (CONFIG_ARM_32)
 # include <asm/arm32/macros.h>
 #elif defined(CONFIG_ARM_64)
-/* No specific ARM64 macros for now */
+# include <asm/arm64/macros.h>
 #else
 # error "unknown ARM variant"
 #endif