Messages in this thread Patch in this message | | | From | Arvind Sankar <> | Date | Mon, 13 Jan 2020 18:06:43 -0500 | Subject | Re: [PATCH v3] x86/vmlinux: Fix vmlinux.lds.S with pre-2.23 binutils |
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On Mon, Jan 13, 2020 at 03:46:04PM -0600, Tom Lendacky wrote: > > @@ -372,7 +374,7 @@ SECTIONS > > * explicitly reserved using memblock_reserve() or it will be discarded > > * and treated as available memory. > > */ > > - __end_of_kernel_reserve = .; > > + __end_of_kernel_reserve = __bss_stop; > > The only thing I worry about is if someone inserts a section between > the bss section and here and doesn't update this value. > > Thanks, > Tom
Could do something like this, or maybe with just the comment?
diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S index bad4e22384dc..25aa1b30068e 100644 --- a/arch/x86/kernel/vmlinux.lds.S +++ b/arch/x86/kernel/vmlinux.lds.S @@ -373,9 +373,16 @@ SECTIONS * automatically reserved in setup_arch(). Anything after here must be * explicitly reserved using memblock_reserve() or it will be discarded * and treated as available memory. + * + * Note that this is defined to use __bss_stop rather than dot for + * compatibility with binutils <2.23, so the definition MUST be updated + * if another section is added after .bss. */ __end_of_kernel_reserve = __bss_stop; + /* Used for build-time check that __end_of_kernel_reserve is correct */ + __end_of_kernel_reserve_check = .; + . = ALIGN(PAGE_SIZE); .brk : AT(ADDR(.brk) - LOAD_OFFSET) { __brk_base = .; @@ -451,6 +458,9 @@ INIT_PER_CPU(irq_stack_backing_store); #endif /* CONFIG_X86_32 */ +. = ASSERT(__end_of_kernel_reserve == __end_of_kernel_reserve_check, + "__end_of_kernel_reserve is incorrectly defined"); + #ifdef CONFIG_KEXEC_CORE #include <asm/kexec.h>
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