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| author | Nicholas Piggin <npiggin@gmail.com> | 2016-09-14 04:24:03 +0200 |
|---|---|---|
| committer | Michal Marek <mmarek@suse.com> | 2016-09-22 14:37:14 +0200 |
| commit | 0f4c4af06eec5717041d6fe568b80ee4cf3c1475 (patch) | |
| tree | 6e6960b1b8fdda70d042f4edda0001818db0c8e3 | |
| parent | kbuild: add arch specific post-link Makefile (diff) | |
| download | linux-0f4c4af06eec5717041d6fe568b80ee4cf3c1475.tar.xz linux-0f4c4af06eec5717041d6fe568b80ee4cf3c1475.zip | |
kbuild: -ffunction-sections fix for archs with conflicting sections
Enabling -ffunction-sections modified the generic linker script to
pull .text.* sections into regular TEXT_TEXT section, conflicting
with some architectures. Revert that change and require archs that
enable the option to ensure they have no conflicting section names,
and do the appropriate merging.
Reported-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Fixes: b67067f1176d ("kbuild: allow archs to select link dead code/data elimination")
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michal Marek <mmarek@suse.com>
| -rw-r--r-- | arch/Kconfig | 4 | ||||
| -rw-r--r-- | include/asm-generic/vmlinux.lds.h | 15 |
2 files changed, 13 insertions, 6 deletions
diff --git a/arch/Kconfig b/arch/Kconfig index 3f948c422d9d..48d1e76a1ee3 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -478,7 +478,9 @@ config LD_DEAD_CODE_DATA_ELIMINATION This requires that the arch annotates or otherwise protects its external entry points from being discarded. Linker scripts must also merge .text.*, .data.*, and .bss.* correctly into - output sections. + output sections. Care must be taken not to pull in unrelated + sections (e.g., '.text.init'). Typically '.' in section names + is used to distinguish them from label names / C identifiers. config HAVE_CONTEXT_TRACKING bool diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h index ad9d8f94dc7a..48dd44f3f24b 100644 --- a/include/asm-generic/vmlinux.lds.h +++ b/include/asm-generic/vmlinux.lds.h @@ -198,9 +198,9 @@ /* * .data section - * -fdata-sections generates .data.identifier which needs to be pulled in - * with .data, but don't want to pull in .data..stuff which has its own - * requirements. Same for bss. + * LD_DEAD_CODE_DATA_ELIMINATION option enables -fdata-sections generates + * .data.identifier which needs to be pulled in with .data, but don't want to + * pull in .data..stuff which has its own requirements. Same for bss. */ #define DATA_DATA \ *(.data .data.[0-9a-zA-Z_]*) \ @@ -434,10 +434,15 @@ } /* .text section. Map to function alignment to avoid address changes - * during second ld run in second ld pass when generating System.map */ + * during second ld run in second ld pass when generating System.map + * LD_DEAD_CODE_DATA_ELIMINATION option enables -ffunction-sections generates + * .text.identifier which needs to be pulled in with .text , but some + * architectures define .text.foo which is not intended to be pulled in here. + * Those enabling LD_DEAD_CODE_DATA_ELIMINATION must ensure they don't have + * conflicting section names, and must pull in .text.[0-9a-zA-Z_]* */ #define TEXT_TEXT \ ALIGN_FUNCTION(); \ - *(.text.hot .text .text.fixup .text.unlikely .text.*) \ + *(.text.hot .text .text.fixup .text.unlikely) \ *(.ref.text) \ MEM_KEEP(init.text) \ MEM_KEEP(exit.text) \ |