Re: [PATCH 2/2] x86/boot/KASLR: Restrict kernel to be randomized in mirror regions if existed

[Baoquan He <bhe@redhat.com>]

On 06/15/17 at 10:04pm, kbuild test robot wrote:
> Hi Baoquan,
> 
> [auto build test WARNING on tip/auto-latest]
> [also build test WARNING on next-20170615]
> [cannot apply to tip/x86/core v4.12-rc5]
> [if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
> 
> url:    https://github.com/0day-ci/linux/commits/Baoquan-He/x86-boot-KASLR-Restrict-kernel-to-be-randomized-in-mirror-regions-if-existed/20170615-204125
> config: i386-defconfig (attached as .config)
> compiler: gcc-6 (Debian 6.2.0-3) 6.2.0 20160901
> reproduce:
>         # save the attached .config to linux build tree
>         make ARCH=i386 
> 
> All warnings (new ones prefixed by >>):
> 
>    arch/x86/boot/compressed/kaslr.c: In function 'process_efi_entry':
> >> arch/x86/boot/compressed/kaslr.c:604:24: warning: 'return' with a value, in function returning void
>                     return -EINVAL;
>                            ^
>    arch/x86/boot/compressed/kaslr.c:566:13: note: declared here
>     static void process_efi_entry(unsigned long minimum, unsigned long image_size)
>                 ^~~~~~~~~~~~~~~~~
> 
> vim +/return +604 arch/x86/boot/compressed/kaslr.c
> 
>    588	
>    589		/*
>    590		 * Mirrored regions are meaningful only if "kernelcore=mirror"
>    591		 * specified.
>    592		 */
>    593		str = strstr(cmdline, "kernelcore=");
>    594		if (!str)
>    595			return;
>    596		str += strlen("kernelcore=");
>    597		if (strncmp(str, "mirror", 6))
>    598			return;
>    599	
>    600	#ifdef CONFIG_X86_32
>    601	       /* Can't handle data above 4GB at this time */
>    602	       if (e->efi_memmap_hi) {
>    603	                warn("Memory map is above 4GB, disabling EFI.\n");
>  > 604	                return -EINVAL;

Yeah, this need be changed. This patchset is not a formal one, there was
unclear issue. Now it has been clarified, will repost a formal one after
test on efi mirror machine passed.


>    605	        }
>    606	        pmap =  e->efi_memmap;
>    607	#else
>    608	        pmap = (e->efi_memmap | ((__u64)e->efi_memmap_hi << 32));
>    609	#endif
>    610	
>    611		nr_desc = e->efi_memmap_size / e->efi_memdesc_size;
>    612		for (i = 0; i < nr_desc; i++) {
> 
> ---
> 0-DAY kernel test infrastructure                Open Source Technology Center
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