On 01.10.2024 10:35, Frediano Ziglio wrote: > On Mon, Sep 30, 2024 at 4:51 PM Jan Beulich <[email protected]> wrote: >> On 26.09.2024 11:21, Frediano Ziglio wrote: >>> @@ -243,7 +234,7 @@ __efi64_mb2_start: >>> /* >>> * Initialize BSS (no nasty surprises!). >>> * It must be done earlier than in BIOS case >>> - * because efi_multiboot2() touches it. >>> + * because efi_multiboot2_prelude() touches it. >>> */ >>> mov %eax, %edx >> >> I think this MOV wants to gain a comment, now that ... >> >>> lea __bss_start(%rip), %edi >>> @@ -252,36 +243,30 @@ __efi64_mb2_start: >>> shr $3, %ecx >>> xor %eax, %eax >>> rep stosq >>> - mov %edx, %eax >> >> ... this one's going away. >> > > What about > > diff --git a/xen/arch/x86/boot/head.S b/xen/arch/x86/boot/head.S > index 89b5e2af88..6fa6ea93e5 100644 > --- a/xen/arch/x86/boot/head.S > +++ b/xen/arch/x86/boot/head.S > @@ -231,12 +231,14 @@ __efi64_mb2_start: > */ > and $~15, %rsp > > + /* Move away magic number, we need it later but we need to use %eax */ > + mov %eax, %edx > + > /* > * Initialize BSS (no nasty surprises!). > * It must be done earlier than in BIOS case > * because efi_multiboot2_prelude() touches it. > */ > - mov %eax, %edx > lea __bss_start(%rip), %edi > lea __bss_end(%rip), %ecx > sub %edi, %ecx > > ??
Fine with me. Maybe s/Move away/Save"? Jan
