From: Daniel Kiper Date: Thu, 25 Aug 2016 12:02:53 +0000 (+0200) Subject: x86/boot: call reloc() using stdcall calling convention X-Git-Tag: archive/raspbian/4.8.0-1+rpi1~1^2~513 X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=8290b39f2b324c1c486ec42f952a1276c9904109;p=xen.git x86/boot: call reloc() using stdcall calling convention Current reloc() call method makes confusion and does not scale well for more arguments. And subsequent patch adding multiboot2 protocol support have to pass 3 arguments instead of 2. Hence, move reloc() call to stdcall calling convention. One may argue that we should use standard cdecl calling convention. However, stdcall is better here than cdecl because we do not need to remove "manually" arguments from stack in xen/arch/x86/boot/head.S assembly file. Suggested-by: Jan Beulich Signed-off-by: Daniel Kiper Acked-by: Jan Beulich --- diff --git a/xen/arch/x86/boot/head.S b/xen/arch/x86/boot/head.S index 85770e8e94..5538a4bda0 100644 --- a/xen/arch/x86/boot/head.S +++ b/xen/arch/x86/boot/head.S @@ -119,7 +119,8 @@ __start: /* Save the Multiboot info struct (after relocation) for later use. */ mov $sym_phys(cpu0_stack)+1024,%esp - push %ebx + push %eax /* Boot trampoline address. */ + push %ebx /* Multiboot information address. */ call reloc mov %eax,sym_phys(multiboot_ptr) diff --git a/xen/arch/x86/boot/reloc.c b/xen/arch/x86/boot/reloc.c index 9ae42e23b8..28c6cea2a6 100644 --- a/xen/arch/x86/boot/reloc.c +++ b/xen/arch/x86/boot/reloc.c @@ -10,15 +10,16 @@ * Keir Fraser */ -/* entered with %eax = BOOT_TRAMPOLINE */ +/* + * This entry point is entered from xen/arch/x86/boot/head.S with: + * - 0x4(%esp) = MULTIBOOT_INFORMATION_ADDRESS, + * - 0x8(%esp) = BOOT_TRAMPOLINE_ADDRESS. + */ asm ( " .text \n" " .globl _start \n" "_start: \n" - " push %eax \n" - " push 0x8(%esp) \n" - " call reloc \n" - " ret $0x4 \n" + " jmp reloc \n" ); typedef unsigned int u32;