On Thu, Jun 22, 2023 at 11:18:03PM +0000, Nathan Chancellor wrote: > If you wanted to restrict it to just LD_IS_BFD in arch/riscv/Kconfig, > that would be fine with me too. > > select HAVE_LD_DEAD_CODE_DATA_ELIMINATION if LD_IS_BFD Hi Jisheng, would you mind sending a v3 with the attached patch applied on top / at the end of your series? > > Nick said he would work on a report for the LLVM side, so as long as > this issue is handled in some way to avoid regressing LLD builds until > it is resolved, I don't think there is anything else for the kernel to > do. We like to have breadcrumbs via issue links, not sure if the report > will be internal to Google or on LLVM's issue tracker though; > regardless, we will have to touch this block to add a version check > later, at which point we can add a link to the fix in LLD. https://github.com/ClangBuiltLinux/linux/issues/1881
>From 3e5e010958ee41b9fb408cfade8fb017c2fe7169 Mon Sep 17 00:00:00 2001 From: Nick Desaulniers <ndesaulniers@xxxxxxxxxx> Date: Fri, 23 Jun 2023 10:06:17 -0700 Subject: [PATCH] riscv: disable HAVE_LD_DEAD_CODE_DATA_ELIMINATION for LLD Linking allyesconfig with ld.lld-17 with CONFIG_DEAD_CODE_ELIMINATION=y takes hours. Assuming this is a performance regression that can be fixed, tentatively disable this for now so that allyesconfig builds don't start timing out. If and when there's a fix to ld.lld, this can be converted to a version check instead so that users of older but still supported versions of ld.lld don't hurt themselves by enabling CONFIG_LD_DEAD_CODE_DATA_ELIMINATION=y. Link: https://github.com/ClangBuiltLinux/linux/issues/1881 Reported-by: Palmer Dabbelt <palmer@xxxxxxxxxxx> Suggested-by: Nathan Chancellor <nathan@xxxxxxxxxx> Signed-off-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx> --- Hi Jisheng, would you mind sending a v3 with this patch on top/at the end of your patch series? arch/riscv/Kconfig | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig index 8effe5bb7788..0573991e9b78 100644 --- a/arch/riscv/Kconfig +++ b/arch/riscv/Kconfig @@ -116,7 +116,8 @@ config RISCV select HAVE_KPROBES if !XIP_KERNEL select HAVE_KPROBES_ON_FTRACE if !XIP_KERNEL select HAVE_KRETPROBES if !XIP_KERNEL - select HAVE_LD_DEAD_CODE_DATA_ELIMINATION + # https://github.com/ClangBuiltLinux/linux/issues/1881 + select HAVE_LD_DEAD_CODE_DATA_ELIMINATION if !LD_IS_LLD select HAVE_MOVE_PMD select HAVE_MOVE_PUD select HAVE_PCI -- 2.41.0.162.gfafddb0af9-goog
