From patchwork Wed Aug 21 19:40:13 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Subject: aarch64: Add assembly support for -fsanitize=hwaddress tagged globals. X-Patchwork-Submitter: =?utf-8?q?Martin_Storsj=C3=B6?= X-Patchwork-Id: 64477 Message-Id: <20190821194013.50497-1-martin@martin.st> To: libav-devel@libav.org Date: Wed, 21 Aug 2019 22:40:13 +0300 From: =?utf-8?q?Martin_Storsj=C3=B6?= List-Id: libav development From: Peter Collingbourne As of LLVM r368102, Clang will set a pointer tag in bits 56-63 of the address of a global when compiling with -fsanitize=hwaddress. This requires an adjustment to assembly code that takes the address of such globals: the code cannot use the regular R_AARCH64_ADR_PREL_PG_HI21 relocation to refer to the global, since the tag would take the address out of range. Instead, the code must use the non-checking (_NC) variant of the relocation (the link-time check is substituted by a runtime check). This change makes the necessary adjustment in the movrel macro, where it is needed when compiling with -fsanitize=hwaddress. Signed-off-by: Peter Collingbourne Signed-off-by: Martin Storsjö --- libavutil/aarch64/asm.S | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/libavutil/aarch64/asm.S b/libavutil/aarch64/asm.S index bf5c1b7ee1..81d723b9b3 100644 --- a/libavutil/aarch64/asm.S +++ b/libavutil/aarch64/asm.S @@ -32,6 +32,10 @@ # define FUNC # #endif +#ifndef __has_feature +# define __has_feature(x) 0 +#endif + .macro function name, export=0, align=2 .macro endfunc ELF .size \name, . - \name @@ -94,7 +98,11 @@ ELF .size \name, . - \name add \rd, \rd, :lo12:\val+(\offset) .endif #elif CONFIG_PIC +# if __has_feature(hwaddress_sanitizer) + adrp \rd, :pg_hi21_nc:\val+(\offset) +# else adrp \rd, \val+(\offset) +# endif add \rd, \rd, :lo12:\val+(\offset) #else ldr \rd, =\val+\offset