[joro:sev-es-kexec 7/12] arch/x86/kernel/sev.c:762:13: warning: no previous prototype for 'sev_es_setup_ap_jump_table_data'

From: kernel test robot
Date: Fri Jul 02 2021 - 18:05:01 EST


tree: https://git.kernel.org/pub/scm/linux/kernel/git/joro/linux.git sev-es-kexec
head: 3467dc3cdbe65c619cd9b5c8db47da63b0655300
commit: 2740e3cdcb62ce9ce27839885b033c3d1f647710 [7/12] x86/sev: Setup code to park APs in the AP Jump Table
config: x86_64-allyesconfig (attached as .config)
compiler: gcc-9 (Debian 9.3.0-22) 9.3.0
reproduce (this is a W=1 build):
# https://git.kernel.org/pub/scm/linux/kernel/git/joro/linux.git/commit/?id=2740e3cdcb62ce9ce27839885b033c3d1f647710
git remote add joro https://git.kernel.org/pub/scm/linux/kernel/git/joro/linux.git
git fetch --no-tags joro sev-es-kexec
git checkout 2740e3cdcb62ce9ce27839885b033c3d1f647710
# save the attached .config to linux build tree
make W=1 ARCH=x86_64

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@xxxxxxxxx>

All warnings (new ones prefixed by >>):

>> arch/x86/kernel/sev.c:762:13: warning: no previous prototype for 'sev_es_setup_ap_jump_table_data' [-Wmissing-prototypes]
762 | void __init sev_es_setup_ap_jump_table_data(void *base, u32 pa)
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


vim +/sev_es_setup_ap_jump_table_data +762 arch/x86/kernel/sev.c

755
756 /*
757 * This function make the necessary runtime changes to the AP Jump Table blob.
758 * For now this only sets up the GDT used while the code executes. The GDT needs
759 * to contain 16-bit code and data segments with a base that points to AP Jump
760 * Table page.
761 */
> 762 void __init sev_es_setup_ap_jump_table_data(void *base, u32 pa)
763 {
764 struct sev_ap_jump_table_header *header;
765 struct desc_ptr *gdt_descr;
766 u64 *ap_jumptable_gdt;
767
768 header = base;
769
770 /*
771 * Setup 16-bit protected mode code and data segments for AP Jumptable.
772 * Set the segment limits to 0xffff to already be compatible with
773 * real-mode.
774 */
775 ap_jumptable_gdt = (u64 *)(base + header->gdt_offset);
776 ap_jumptable_gdt[SEV_APJT_CS16 / 8] = GDT_ENTRY(0x9b, pa, 0xffff);
777 ap_jumptable_gdt[SEV_APJT_DS16 / 8] = GDT_ENTRY(0x93, pa, 0xffff);
778
779 /* Write correct GDT base address into GDT descriptor */
780 gdt_descr = (struct desc_ptr *)(base + header->gdt_offset);
781 gdt_descr->address += pa;
782 }
783

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Attachment: .config.gz
Description: application/gzip