From d0e3378ad73ed80d4baab95e2c3aaa0a18ae7747 Mon Sep 17 00:00:00 2001 From: Tom Rini Date: Tue, 28 Mar 2023 14:54:51 -0400 Subject: [PATCH] linker_lists: Rework start/end macros to not rely on undefined behavior Per the GCC bug listed below, the way we do linker lists is relying on undefined behavior that seems to work in gcc, but doesn't always work in clang. Andrew suggests rewriting our start/end macros in a different way (as implemented here, from what he said in comment 1) to avoid these problems. Reported-by: AdityaK Suggested-by: Andrew Pinski Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108915 Signed-off-by: Tom Rini Reviewed-by: Simon Glass Reviewed-by: Andrew Pinski --- include/linker_lists.h | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-) diff --git a/include/linker_lists.h b/include/linker_lists.h index d3da9d44e8..f9a2ee0c76 100644 --- a/include/linker_lists.h +++ b/include/linker_lists.h @@ -127,7 +127,9 @@ static char start[0] __aligned(CONFIG_LINKER_LIST_ALIGN) \ __attribute__((unused)) \ __section("__u_boot_list_2_"#_list"_1"); \ - (_type *)&start; \ + _type * tmp = (_type *)&start; \ + asm("":"+r"(tmp)); \ + tmp; \ }) /** @@ -153,7 +155,9 @@ ({ \ static char end[0] __aligned(4) __attribute__((unused)) \ __section("__u_boot_list_2_"#_list"_3"); \ - (_type *)&end; \ + _type * tmp = (_type *)&end; \ + asm("":"+r"(tmp)); \ + tmp; \ }) /** * ll_entry_count() - Return the number of elements in linker-generated array @@ -247,7 +251,9 @@ ({ \ static char start[0] __aligned(4) __attribute__((unused)) \ __section("__u_boot_list_1"); \ - (_type *)&start; \ + _type * tmp = (_type *)&start; \ + asm("":"+r"(tmp)); \ + tmp; \ }) /** @@ -270,7 +276,9 @@ ({ \ static char end[0] __aligned(4) __attribute__((unused)) \ __section("__u_boot_list_3"); \ - (_type *)&end; \ + _type * tmp = (_type *)&end; \ + asm("":"+r"(tmp)); \ + tmp; \ }) #endif /* __ASSEMBLY__ */ -- 2.39.5