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authorMax Krummenacher <max.krummenacher@toradex.com>2018-03-13 11:32:58 +0100
committerMax Krummenacher <max.krummenacher@toradex.com>2018-03-13 11:32:58 +0100
commit6fb9f3c8a4992f67dcb3ce413df2e22e96b2d400 (patch)
tree6e3071b2f179a62b027669ac2a238383293bf941 /arch/x86/lib/retpoline.S
parenta126a5e5dc2fcc5cb36af14c89b440cc8e3bab30 (diff)
parent8b5ab55d254f36e89b1b53aeac7223d2d102483e (diff)
Merge tag 'v4.4.121' into toradex_vf_4.4-nextColibri-VF_LXDE-Image_2.8b2.97-20180331
This is the 4.4.121 stable release
Diffstat (limited to 'arch/x86/lib/retpoline.S')
-rw-r--r--arch/x86/lib/retpoline.S48
1 files changed, 48 insertions, 0 deletions
diff --git a/arch/x86/lib/retpoline.S b/arch/x86/lib/retpoline.S
new file mode 100644
index 000000000000..3d06b482ebc7
--- /dev/null
+++ b/arch/x86/lib/retpoline.S
@@ -0,0 +1,48 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#include <linux/stringify.h>
+#include <linux/linkage.h>
+#include <asm/dwarf2.h>
+#include <asm/cpufeature.h>
+#include <asm/alternative-asm.h>
+#include <asm-generic/export.h>
+#include <asm/nospec-branch.h>
+
+.macro THUNK reg
+ .section .text.__x86.indirect_thunk
+
+ENTRY(__x86_indirect_thunk_\reg)
+ CFI_STARTPROC
+ JMP_NOSPEC %\reg
+ CFI_ENDPROC
+ENDPROC(__x86_indirect_thunk_\reg)
+.endm
+
+/*
+ * Despite being an assembler file we can't just use .irp here
+ * because __KSYM_DEPS__ only uses the C preprocessor and would
+ * only see one instance of "__x86_indirect_thunk_\reg" rather
+ * than one per register with the correct names. So we do it
+ * the simple and nasty way...
+ */
+#define __EXPORT_THUNK(sym) _ASM_NOKPROBE(sym); EXPORT_SYMBOL(sym)
+#define EXPORT_THUNK(reg) __EXPORT_THUNK(__x86_indirect_thunk_ ## reg)
+#define GENERATE_THUNK(reg) THUNK reg ; EXPORT_THUNK(reg)
+
+GENERATE_THUNK(_ASM_AX)
+GENERATE_THUNK(_ASM_BX)
+GENERATE_THUNK(_ASM_CX)
+GENERATE_THUNK(_ASM_DX)
+GENERATE_THUNK(_ASM_SI)
+GENERATE_THUNK(_ASM_DI)
+GENERATE_THUNK(_ASM_BP)
+#ifdef CONFIG_64BIT
+GENERATE_THUNK(r8)
+GENERATE_THUNK(r9)
+GENERATE_THUNK(r10)
+GENERATE_THUNK(r11)
+GENERATE_THUNK(r12)
+GENERATE_THUNK(r13)
+GENERATE_THUNK(r14)
+GENERATE_THUNK(r15)
+#endif