Messages in this thread | | | Date | Sun, 5 Apr 2020 17:47:29 +0100 (BST) | From | "Maciej W. Rozycki" <> | Subject | Re: [PATCH] MIPS: malta: Set load address for 32bit kernel correctly |
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On Sun, 5 Apr 2020, Jiaxun Yang wrote:
> LLD failed to link vmlinux with 64bit load address for 32bit ELF > while bfd will strip 64bit address into 32bit silently. > To fix LLD build, we should supply a 32bit load address for 32bit > kernel. [...] > diff --git a/arch/mips/mti-malta/Platform b/arch/mips/mti-malta/Platform > index 2cc72c9b38e3..f9b49cba1764 100644 > --- a/arch/mips/mti-malta/Platform > +++ b/arch/mips/mti-malta/Platform > @@ -6,6 +6,10 @@ cflags-$(CONFIG_MIPS_MALTA) += -I$(srctree)/arch/mips/include/asm/mach-malta > ifdef CONFIG_KVM_GUEST > load-$(CONFIG_MIPS_MALTA) += 0x0000000040100000 > else > +ifdef CONFIG_64BIT > load-$(CONFIG_MIPS_MALTA) += 0xffffffff80100000 > +else > + load-$(CONFIG_MIPS_MALTA) += 0x80100000
Given the description above I think it should be done uniformly and automatically across all platforms by trimming the address supplied with $(load-y) to low 8 digits in a single place, that is at the place where the variable is consumed. This will reduce clutter across Makefile fragments, avoid inconsistencies and extra work to handle individual platforms as the problem is triggered over and over again, and limit the risk of mistakes.
Some error checking might be doable for verifying that the 64-bit address truncated is a sign-extended 32-bit value, but that perhaps would be an overkill as certainly any 64-bit system that sets the load address to be outside the sign-extended 32-bit address range does not support a !64BIT configuration anyway.
Maciej
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