Message ID | 20190815180022.129027-1-pcc@google.com |
---|---|
State | Accepted |
Commit | 9bcb1cb6ed50e66e0489beb871eed83533b3de97 |
Headers | show |
On Thu, Aug 15, 2019 at 11:00 AM Peter Collingbourne <pcc@google.com> wrote: > > 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. It came to my attention that this patch was sent without a Signed-off-by line. Will send a v2 with the Signed-off-by. Peter
diff --git a/libavutil/aarch64/asm.S b/libavutil/aarch64/asm.S index 5c329430fd..3ac2ba0d52 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