Messages in this thread Patch in this message | | | From | Arvind Sankar <> | Subject | [PATCH] x86/build: Fix vmlinux size check on 64-bit | Date | Mon, 5 Oct 2020 11:15:39 -0400 |
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Commit b4e0409a36f4 ("x86: check vmlinux limits, 64-bit") added a check that the size of the 64-bit kernel is less than KERNEL_IMAGE_SIZE.
The check uses (_end - _text), but this is not enough. The initial PMD used in startup_64() (level2_kernel_pgt) can only map upto KERNEL_IMAGE_SIZE from __START_KERNEL_map, not from _text.
The correct check is the same as for 32-bit, since LOAD_OFFSET is defined appropriately for the two architectures. Just check (_end - LOAD_OFFSET) against KERNEL_IMAGE_SIZE unconditionally.
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu> --- arch/x86/kernel/vmlinux.lds.S | 11 ++--------- 1 file changed, 2 insertions(+), 9 deletions(-)
diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S index bf9e0adb5b7e..b38832821b98 100644 --- a/arch/x86/kernel/vmlinux.lds.S +++ b/arch/x86/kernel/vmlinux.lds.S @@ -454,13 +454,12 @@ SECTIONS ASSERT(SIZEOF(.rela.dyn) == 0, "Unexpected run-time relocations (.rela) detected!") } -#ifdef CONFIG_X86_32 /* * The ASSERT() sink to . is intentional, for binutils 2.14 compatibility: */ . = ASSERT((_end - LOAD_OFFSET <= KERNEL_IMAGE_SIZE), "kernel image bigger than KERNEL_IMAGE_SIZE"); -#else +#ifdef CONFIG_X86_64 /* * Per-cpu symbols which need to be offset from __per_cpu_load * for the boot processor. @@ -470,18 +469,12 @@ INIT_PER_CPU(gdt_page); INIT_PER_CPU(fixed_percpu_data); INIT_PER_CPU(irq_stack_backing_store); -/* - * Build-time check on the image size: - */ -. = ASSERT((_end - _text <= KERNEL_IMAGE_SIZE), - "kernel image bigger than KERNEL_IMAGE_SIZE"); - #ifdef CONFIG_SMP . = ASSERT((fixed_percpu_data == 0), "fixed_percpu_data is not at start of per-cpu area"); #endif -#endif /* CONFIG_X86_32 */ +#endif /* CONFIG_X86_64 */ #ifdef CONFIG_KEXEC_CORE #include <asm/kexec.h> -- 2.26.2
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