arm64: use a common .arch preamble for inline assembly

Commit 7c78f67e9bd9 ("arm64: enable tlbi range instructions") breaks
LLVM's integrated assembler, because -Wa,-march is only passed to
external assemblers and therefore, the new instructions are not enabled
when IAS is used.

This change adds a common architecture version preamble, which can be
used in inline assembly blocks that contain instructions that require
a newer architecture version, and uses it to fix __TLBI_0 and __TLBI_1
with ARM64_TLB_RANGE.

Fixes: 7c78f67e9bd9 ("arm64: enable tlbi range instructions")
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Tested-by: Nathan Chancellor <natechancellor@gmail.com>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Link: https://github.com/ClangBuiltLinux/linux/issues/1106
Link: https://lore.kernel.org/r/20200827203608.1225689-1-samitolvanen@google.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile
index b45f012..20ab5c9 100644 (file)
--- a/arch/arm64/Makefile
+++ b/arch/arm64/Makefile
@@ -82,8 +82,8 @@ endif
 # compiler to generate them and consequently to break the single image contract
 # we pass it only to the assembler. This option is utilized only in case of non
 # integrated assemblers.
-ifneq ($(CONFIG_AS_HAS_ARMV8_4), y)
-branch-prot-flags-$(CONFIG_AS_HAS_PAC) += -Wa,-march=armv8.3-a
+ifeq ($(CONFIG_AS_HAS_PAC), y)
+asm-arch := armv8.3-a
 endif
 endif
 
@@ -91,7 +91,12 @@ KBUILD_CFLAGS += $(branch-prot-flags-y)
 
 ifeq ($(CONFIG_AS_HAS_ARMV8_4), y)
 # make sure to pass the newest target architecture to -march.
-KBUILD_CFLAGS  += -Wa,-march=armv8.4-a
+asm-arch := armv8.4-a
+endif
+
+ifdef asm-arch
+KBUILD_CFLAGS  += -Wa,-march=$(asm-arch) \
+                  -DARM64_ASM_ARCH='"$(asm-arch)"'
 endif
 
 ifeq ($(CONFIG_SHADOW_CALL_STACK), y)

diff --git a/arch/arm64/include/asm/compiler.h b/arch/arm64/include/asm/compiler.h
index 51a7ce8..6fb2e6b 100644 (file)
--- a/arch/arm64/include/asm/compiler.h
+++ b/arch/arm64/include/asm/compiler.h
@@ -2,6 +2,12 @@
 #ifndef __ASM_COMPILER_H
 #define __ASM_COMPILER_H
 
+#ifdef ARM64_ASM_ARCH
+#define ARM64_ASM_PREAMBLE ".arch " ARM64_ASM_ARCH "\n"
+#else
+#define ARM64_ASM_PREAMBLE
+#endif
+
 /*
  * The EL0/EL1 pointer bits used by a pointer authentication code.
  * This is dependent on TBI0/TBI1 being enabled, or bits 63:56 would also apply.

diff --git a/arch/arm64/include/asm/tlbflush.h b/arch/arm64/include/asm/tlbflush.h
index d493174..cc3f5a3 100644 (file)
--- a/arch/arm64/include/asm/tlbflush.h
+++ b/arch/arm64/include/asm/tlbflush.h
@@ -28,14 +28,16 @@
  * not. The macros handles invoking the asm with or without the
  * register argument as appropriate.
  */
-#define __TLBI_0(op, arg) asm ("tlbi " #op "\n"                                       \
+#define __TLBI_0(op, arg) asm (ARM64_ASM_PREAMBLE                             \
+                              "tlbi " #op "\n"                                \
                   ALTERNATIVE("nop\n                   nop",                  \
                               "dsb ish\n               tlbi " #op,            \
                               ARM64_WORKAROUND_REPEAT_TLBI,                   \
                               CONFIG_ARM64_WORKAROUND_REPEAT_TLBI)            \
                            : : )
 
-#define __TLBI_1(op, arg) asm ("tlbi " #op ", %0\n"                           \
+#define __TLBI_1(op, arg) asm (ARM64_ASM_PREAMBLE                             \
+                              "tlbi " #op ", %0\n"                            \
                   ALTERNATIVE("nop\n                   nop",                  \
                               "dsb ish\n               tlbi " #op ", %0",     \
                               ARM64_WORKAROUND_REPEAT_TLBI,                   \