[PATCH v3] grub-core: Build fixes for i386

[PATCH v3] grub-core: Build fixes for i386

[Jan (janneke) Nieuwenhuizen]

This fixes cross-compiling to x86 (e.g., the Hurd) from x86-linux of

    grub-core/lib/i386/relocator64.S

This file has six sections that only build with a 64-bit assembler,
yet only the first two sections had support for a 32-bit assembler;
this patch completes this for the remaining sections.

To reproduce, update the GRUB source description in your local Guix
archive and run

   ./pre-inst-env guix build --system=i686-linux --target=i586-pc-gnu grub

or install an x86 cross-build environment on x86-linux (32-bit!) and
configure to cross build and make, e.g., do something like

    ./configure \
       CC_FOR_BUILD=gcc \
       --build=i686-unknown-linux-gnu \
       --host=i586-pc-gnu
    make

Signed-off-by: Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
---
 grub-core/lib/i386/relocator64.S | 27 +++++++++++++++++++++++++--
 1 file changed, 25 insertions(+), 2 deletions(-)

diff --git a/grub-core/lib/i386/relocator64.S b/grub-core/lib/i386/relocator64.S
index 148f38adb..b8b1f896b 100644
--- a/grub-core/lib/i386/relocator64.S
+++ b/grub-core/lib/i386/relocator64.S
@@ -63,7 +63,9 @@ VARIABLE(grub_relocator64_cr3)
 	movq	%rax, %cr3
 #endif
 
+#ifdef __x86_64__
 	.code64
+#endif
 
 	/* mov imm64, %rax */
 	.byte 	0x48
@@ -71,7 +73,14 @@ VARIABLE(grub_relocator64_cr3)
 VARIABLE(grub_relocator64_rsp)
 	.quad	0
 
+#ifdef __x86_64__
 	movq	%rax, %rsp
+#else
+	/* movq	%rax, %rsp */
+	.byte 	0x48
+	.byte	0x89
+	.byte	0xc4
+#endif
 
 #ifdef GRUB_MACHINE_EFI
 	jmp	LOCAL(skip_efi_stack_align)
@@ -85,7 +94,14 @@ VARIABLE(grub_relocator64_rsp)
 	 */
 VARIABLE(grub_relocator64_efi_start)
 	/* Align the stack as UEFI spec requires. */
+#ifdef __x86_64__
 	andq	$~15, %rsp
+#else
+	.byte 0x48
+	.byte 0x83
+	.byte 0xe4
+	.byte 0xf0
+#endif
 
 LOCAL(skip_efi_stack_align):
 #endif
@@ -95,8 +111,15 @@ LOCAL(skip_efi_stack_align):
 VARIABLE(grub_relocator64_rsi)
 	.quad	0
 
+#ifdef	__x86_64__
 	movq	%rax, %rsi
-	
+#else
+	/* movq	%rax, %rsi */
+	.byte 	0x48
+	.byte	0x89
+	.byte 	0xc6
+#endif
+
 	/* mov imm64, %rax */
 	.byte 	0x48
 	.byte	0xb8
@@ -125,7 +148,7 @@ VARIABLE(grub_relocator64_rdx)
 	   payload and makes this implementation easier.  */
 	cld
 
-#ifdef __APPLE__
+#if defined (__APPLE__) || !defined (__x86_64__)
 	.byte 0xff, 0x25
 	.quad 0
 #else
-- 
Jan Nieuwenhuizen <janneke@gnu.org> | GNU LilyPond http://lilypond.org
Freelance IT http://JoyofSource.com | Avatar® http://AvatarAcademy.com

Re: [PATCH v3] grub-core: Build fixes for i386

[Daniel Kiper]

On Wed, May 26, 2021 at 08:18:24PM +0200, Jan (janneke) Nieuwenhuizen wrote:
> This fixes cross-compiling to x86 (e.g., the Hurd) from x86-linux of
>
>     grub-core/lib/i386/relocator64.S
>
> This file has six sections that only build with a 64-bit assembler,
> yet only the first two sections had support for a 32-bit assembler;
> this patch completes this for the remaining sections.
>
> To reproduce, update the GRUB source description in your local Guix
> archive and run
>
>    ./pre-inst-env guix build --system=i686-linux --target=i586-pc-gnu grub
>
> or install an x86 cross-build environment on x86-linux (32-bit!) and
> configure to cross build and make, e.g., do something like
>
>     ./configure \
>        CC_FOR_BUILD=gcc \
>        --build=i686-unknown-linux-gnu \
>        --host=i586-pc-gnu
>     make
>
> Signed-off-by: Jan (janneke) Nieuwenhuizen <janneke@gnu.org>

Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com> except these "empty"
line changes. Though I will fix them before committing...

Thank you for fixing this issue...

Daniel