Messages in this thread | | | From | Arnd Bergmann <> | Date | Tue, 16 Mar 2021 17:39:27 +0100 | Subject | Re: [PATCH] arm64: vmlinux.lds.S: keep .entry.tramp.text section |
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On Tue, Mar 16, 2021 at 5:27 PM Catalin Marinas <catalin.marinas@arm.com> wrote: > > On Tue, Mar 16, 2021 at 10:45:32AM +0000, Catalin Marinas wrote: > > On Fri, Feb 26, 2021 at 08:32:57PM -0800, Fangrui Song wrote: > > > On 2021-02-26, Kees Cook wrote: > > > > On Fri, Feb 26, 2021 at 03:03:39PM +0100, Arnd Bergmann wrote: > > > > > From: Arnd Bergmann <arnd@arndb.de> > > > > > > > > > > When building with CONFIG_LD_DEAD_CODE_DATA_ELIMINATION, > > > > > I sometimes see an assertion > > > > > > > > > > ld.lld: error: Entry trampoline text too big > > > > > > > > Heh, "too big" seems a weird report for having it discarded. :) > > > > > > > > Any idea on this Fangrui? > > > > > > > > ( I see this is https://github.com/ClangBuiltLinux/linux/issues/1311 ) > > > > > > This diagnostic is from an ASSERT in arch/arm64/kernel/vmlinux.lds > > > > > > ASSERT((__entry_tramp_text_end - __entry_tramp_text_start) == (1 << 16), > > > "Entry trampoline text too big") > > > > Can we not change the ASSERT to be <= PAGE_SIZE instead? > > Ah, that won't work as I suspect we still need the trampoline section. > > Arnd, do you know why this section disappears? I did a simple test with > defconfig + LD_DEAD_CODE_DATA_ELIMINATION and the trampoline section is > still around.
If I remember correctly, this showed up when CONFIG_ARM_SDE_INTERFACE is disabled, which dropped the only reference into this section. If that doesn't make sense, I can try digging through the old build logs to reproduce the problem.
Arnd
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