RE: [PATCH 1/4] xen/PVH: Replace GDT_ENTRY with explicit constant

[David Laight]

From: Boris Ostrovsky
> Sent: 30 April 2018 17:24
> To: linux-kernel@xxxxxxxxxxxxxxx; xen-devel@xxxxxxxxxxxxxxxxxxxx
> Cc: jgross@xxxxxxxx; Boris Ostrovsky; stable@xxxxxxxxxxxxxxx
> Subject: [PATCH 1/4] xen/PVH: Replace GDT_ENTRY with explicit constant
> 
> Latest binutils release (2.29.1) will no longer allow proper computation
> of GDT entries on 32-bits, with warning:
> 
> arch/x86/xen/xen-pvh.S: Assembler messages:
> arch/x86/xen/xen-pvh.S:150: Warning: shift count out of range (32 is not between 0 and 31)
> arch/x86/xen/xen-pvh.S:150: Warning: shift count out of range (40 is not between 0 and 31)
> arch/x86/xen/xen-pvh.S:150: Warning: shift count out of range (32 is not between 0 and 31)
> arch/x86/xen/xen-pvh.S:152: Warning: shift count out of range (32 is not between 0 and 31)
> arch/x86/xen/xen-pvh.S:152: Warning: shift count out of range (40 is not between 0 and 31)
> arch/x86/xen/xen-pvh.S:152: Warning: shift count out of range (32 is not between 0 and 31)
> 
> Use explicit value of the entry instead of using GDT_ENTRY() macro.
...
>  #ifdef CONFIG_X86_64
> -	.quad GDT_ENTRY(0xa09a, 0, 0xfffff) /* __KERNEL_CS */
> +	.quad 0x00af9a000000ffff            /* __BOOT_CS */
>  #else
> -	.quad GDT_ENTRY(0xc09a, 0, 0xfffff) /* __KERNEL_CS */
> +	.quad 0x00cf9a000000ffff            /* __BOOT_CS */
>  #endif
> -	.quad GDT_ENTRY(0xc092, 0, 0xfffff) /* __KERNEL_DS */
> +	.quad 0x00cf92000000ffff            /* __BOOT_DS */
>  gdt_end:

It has to be possible to fix the GDT_ENTRY() macro.
Even if you end up with one that generates two 32bit values.

You've also changed the name in the comments.

	David