From: Nathan Chancellor Date: Thu, 20 Mar 2025 21:33:49 +0000 (+0100) Subject: ARM: 9443/1: Require linker to support KEEP within OVERLAY for DCE X-Git-Tag: v6.15-rc1~34^2~2 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=e7607f7d6d81;p=thirdparty%2Fkernel%2Flinux.git ARM: 9443/1: Require linker to support KEEP within OVERLAY for DCE ld.lld prior to 21.0.0 does not support using the KEEP keyword within an overlay description, which may be needed to avoid discarding necessary sections within an overlay with '--gc-sections', which can be enabled for the kernel via CONFIG_LD_DEAD_CODE_DATA_ELIMINATION. Disallow CONFIG_LD_DEAD_CODE_DATA_ELIMINATION without support for KEEP within OVERLAY and introduce a macro, OVERLAY_KEEP, that can be used to conditionally add KEEP when it is properly supported to avoid breaking old versions of ld.lld. Cc: stable@vger.kernel.org Link: https://github.com/llvm/llvm-project/commit/381599f1fe973afad3094e55ec99b1620dba7d8c Reviewed-by: Linus Walleij Signed-off-by: Nathan Chancellor Signed-off-by: Russell King (Oracle) --- diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index 202dbd17ad2ff..25ed6f1a7c7ae 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -121,7 +121,7 @@ config ARM select HAVE_KERNEL_XZ select HAVE_KPROBES if !XIP_KERNEL && !CPU_ENDIAN_BE32 && !CPU_V7M select HAVE_KRETPROBES if HAVE_KPROBES - select HAVE_LD_DEAD_CODE_DATA_ELIMINATION if (LD_VERSION >= 23600 || LD_IS_LLD) + select HAVE_LD_DEAD_CODE_DATA_ELIMINATION if (LD_VERSION >= 23600 || LD_CAN_USE_KEEP_IN_OVERLAY) select HAVE_MOD_ARCH_SPECIFIC select HAVE_NMI select HAVE_OPTPROBES if !THUMB2_KERNEL diff --git a/arch/arm/include/asm/vmlinux.lds.h b/arch/arm/include/asm/vmlinux.lds.h index 89697f2047159..a54db342653ab 100644 --- a/arch/arm/include/asm/vmlinux.lds.h +++ b/arch/arm/include/asm/vmlinux.lds.h @@ -34,6 +34,12 @@ #define NOCROSSREFS #endif +#ifdef CONFIG_LD_CAN_USE_KEEP_IN_OVERLAY +#define OVERLAY_KEEP(x) KEEP(x) +#else +#define OVERLAY_KEEP(x) x +#endif + /* Set start/end symbol names to the LMA for the section */ #define ARM_LMA(sym, section) \ sym##_start = LOADADDR(section); \ diff --git a/init/Kconfig b/init/Kconfig index d0d021b3fa3b3..fc994f5cd5dba 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -129,6 +129,11 @@ config CC_HAS_COUNTED_BY # https://github.com/llvm/llvm-project/pull/112636 depends on !(CC_IS_CLANG && CLANG_VERSION < 190103) +config LD_CAN_USE_KEEP_IN_OVERLAY + # ld.lld prior to 21.0.0 did not support KEEP within an overlay description + # https://github.com/llvm/llvm-project/pull/130661 + def_bool LD_IS_BFD || LLD_VERSION >= 210000 + config RUSTC_HAS_COERCE_POINTEE def_bool RUSTC_VERSION >= 108400