From: Roger Pau Monné <roger.pau@citrix.com>
Multiboot and PVH booting are not supported for PE, hence discards them
in the linker script when doing a PE build.
That removes some relocations that otherwise appear due to the usage of the
start and __efi64_mb2_start symbols in the multiboot2 header.
Section discarding is not done updating DISCARD_SECTIONS definition as the
change is specific for x86.
No functional change intended.
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Signed-off-by: Frediano Ziglio <frediano.ziglio@citrix.com>
---
Changes since v1:
- improve commit message;
- change section orders to avoid changing code order in final executable;
- merge 2 commits;
- removed deprecated documentation section.
Changes since v2:
- Update commit message, join 2 sentences together.
Changes since v3:
- Added Acked-by.
Changes since v4:
- more clear subject;
- removed more code/data from EFI output;
- removed Acked-by.
Changes since v5:
- simplify section exclusion using more wildcard;
- exclude more multiboot functions.
---
docs/hypervisor-guide/x86/how-xen-boots.rst | 6 ------
xen/arch/x86/boot/head.S | 8 ++++----
xen/arch/x86/xen.lds.S | 7 +++++++
xen/tools/combine_two_binaries.py | 2 +-
4 files changed, 12 insertions(+), 11 deletions(-)
diff --git a/docs/hypervisor-guide/x86/how-xen-boots.rst b/docs/hypervisor-guide/x86/how-xen-boots.rst
index 8b3229005c..b6d852050a 100644
--- a/docs/hypervisor-guide/x86/how-xen-boots.rst
+++ b/docs/hypervisor-guide/x86/how-xen-boots.rst
@@ -82,12 +82,6 @@ When a PEI-capable toolchain is found, the objects are linked together and a
PE32+ binary is created. It can be run directly from the EFI shell, and has
``efi_start`` as its entry symbol.
-.. note::
-
- xen.efi does contain all MB1/MB2/PVH tags included in the rest of the
- build. However, entry via anything other than the EFI64 protocol is
- unsupported, and won't work.
-
Boot
----
diff --git a/xen/arch/x86/boot/head.S b/xen/arch/x86/boot/head.S
index 68b963ce6f..981f262b5e 100644
--- a/xen/arch/x86/boot/head.S
+++ b/xen/arch/x86/boot/head.S
@@ -126,7 +126,7 @@ multiboot2_header:
.size multiboot2_header, . - multiboot2_header
.type multiboot2_header, @object
- .section .init.rodata, "a", @progbits
+ .section .init.rodata.multiboot, "a", @progbits
.Lbad_cpu_msg: .asciz "ERR: Not a 64-bit CPU!"
.Lbad_ldr_msg: .asciz "ERR: Not a Multiboot bootloader!"
@@ -137,8 +137,7 @@ multiboot2_header:
.Lno_nx_msg: .asciz "ERR: Not an NX-capable CPU!"
#endif
- .section .init.data, "aw", @progbits
- .subsection 1 /* Put data here after the page tables (in x86_64.S). */
+ .section .init.data.multiboot, "aw", @progbits
.align 4
.word 0
@@ -154,7 +153,7 @@ vga_text_buffer:
efi_platform:
.byte 0
- .section .init.text, "ax", @progbits
+ .section .init.multiboot, "ax", @progbits
early_error: /* Here to improve the disassembly. */
@@ -712,6 +711,7 @@ trampoline_setup:
/* Jump into the relocated trampoline. */
lret
+ .section .init.text, "ax", @progbits
ENTRY(trampoline_start)
#include "trampoline.S"
ENTRY(trampoline_end)
diff --git a/xen/arch/x86/xen.lds.S b/xen/arch/x86/xen.lds.S
index 8e63cf5bc2..4ed1d2bec1 100644
--- a/xen/arch/x86/xen.lds.S
+++ b/xen/arch/x86/xen.lds.S
@@ -57,6 +57,10 @@ SECTIONS
__image_base__ = .;
#else
. = __image_base__;
+ /DISCARD/ : {
+ *(.text.header)
+ *(.init.*multiboot)
+ }
#endif
#if 0
@@ -195,6 +199,7 @@ SECTIONS
DECL_SECTION(.init.text) {
#endif
_sinittext = .;
+ *(.init.multiboot)
*(.init.text)
*(.text.startup)
_einittext = .;
@@ -220,6 +225,7 @@ SECTIONS
*(.init.rodata.cf_clobber)
__initdata_cf_clobber_end = .;
+ *(.init.rodata.multiboot)
*(.init.rodata)
*(.init.rodata.*)
@@ -234,6 +240,7 @@ SECTIONS
*(.initcall1.init)
__initcall_end = .;
+ *(.init.data.multiboot)
*(.init.data)
*(.init.data.rel)
*(.init.data.rel.*)
diff --git a/xen/tools/combine_two_binaries.py b/xen/tools/combine_two_binaries.py
index 581e57cbc0..5f0433dcad 100755
--- a/xen/tools/combine_two_binaries.py
+++ b/xen/tools/combine_two_binaries.py
@@ -33,7 +33,7 @@ parser.add_argument('--map', dest='mapfile',
parser.add_argument('--exports', dest='exports',
help='Symbols to export')
parser.add_argument('--section-header', dest='section_header',
- default='.section .init.text, "ax", @progbits',
+ default='.section .init.multiboot, "ax", @progbits',
help='Section header declaration')
parser.add_argument('-v', '--verbose',
action='store_true')
--
2.43.0
On Mon, Jul 06, 2026 at 11:45:55AM +0100, Frediano Ziglio wrote:
> From: Roger Pau Monné <roger.pau@citrix.com>
>
> Multiboot and PVH booting are not supported for PE, hence discards them
> in the linker script when doing a PE build.
>
> That removes some relocations that otherwise appear due to the usage of the
> start and __efi64_mb2_start symbols in the multiboot2 header.
>
> Section discarding is not done updating DISCARD_SECTIONS definition as the
> change is specific for x86.
>
> No functional change intended.
>
> Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
> Signed-off-by: Frediano Ziglio <frediano.ziglio@citrix.com>
Acked-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
> ---
> Changes since v1:
> - improve commit message;
> - change section orders to avoid changing code order in final executable;
> - merge 2 commits;
> - removed deprecated documentation section.
>
> Changes since v2:
> - Update commit message, join 2 sentences together.
>
> Changes since v3:
> - Added Acked-by.
>
> Changes since v4:
> - more clear subject;
> - removed more code/data from EFI output;
> - removed Acked-by.
>
> Changes since v5:
> - simplify section exclusion using more wildcard;
> - exclude more multiboot functions.
> ---
> docs/hypervisor-guide/x86/how-xen-boots.rst | 6 ------
> xen/arch/x86/boot/head.S | 8 ++++----
> xen/arch/x86/xen.lds.S | 7 +++++++
> xen/tools/combine_two_binaries.py | 2 +-
> 4 files changed, 12 insertions(+), 11 deletions(-)
>
> diff --git a/docs/hypervisor-guide/x86/how-xen-boots.rst b/docs/hypervisor-guide/x86/how-xen-boots.rst
> index 8b3229005c..b6d852050a 100644
> --- a/docs/hypervisor-guide/x86/how-xen-boots.rst
> +++ b/docs/hypervisor-guide/x86/how-xen-boots.rst
> @@ -82,12 +82,6 @@ When a PEI-capable toolchain is found, the objects are linked together and a
> PE32+ binary is created. It can be run directly from the EFI shell, and has
> ``efi_start`` as its entry symbol.
>
> -.. note::
> -
> - xen.efi does contain all MB1/MB2/PVH tags included in the rest of the
> - build. However, entry via anything other than the EFI64 protocol is
> - unsupported, and won't work.
> -
>
> Boot
> ----
> diff --git a/xen/arch/x86/boot/head.S b/xen/arch/x86/boot/head.S
> index 68b963ce6f..981f262b5e 100644
> --- a/xen/arch/x86/boot/head.S
> +++ b/xen/arch/x86/boot/head.S
> @@ -126,7 +126,7 @@ multiboot2_header:
> .size multiboot2_header, . - multiboot2_header
> .type multiboot2_header, @object
>
> - .section .init.rodata, "a", @progbits
> + .section .init.rodata.multiboot, "a", @progbits
>
> .Lbad_cpu_msg: .asciz "ERR: Not a 64-bit CPU!"
> .Lbad_ldr_msg: .asciz "ERR: Not a Multiboot bootloader!"
> @@ -137,8 +137,7 @@ multiboot2_header:
> .Lno_nx_msg: .asciz "ERR: Not an NX-capable CPU!"
> #endif
>
> - .section .init.data, "aw", @progbits
> - .subsection 1 /* Put data here after the page tables (in x86_64.S). */
> + .section .init.data.multiboot, "aw", @progbits
> .align 4
>
> .word 0
> @@ -154,7 +153,7 @@ vga_text_buffer:
> efi_platform:
> .byte 0
>
> - .section .init.text, "ax", @progbits
> + .section .init.multiboot, "ax", @progbits
>
> early_error: /* Here to improve the disassembly. */
>
> @@ -712,6 +711,7 @@ trampoline_setup:
> /* Jump into the relocated trampoline. */
> lret
>
> + .section .init.text, "ax", @progbits
> ENTRY(trampoline_start)
> #include "trampoline.S"
> ENTRY(trampoline_end)
> diff --git a/xen/arch/x86/xen.lds.S b/xen/arch/x86/xen.lds.S
> index 8e63cf5bc2..4ed1d2bec1 100644
> --- a/xen/arch/x86/xen.lds.S
> +++ b/xen/arch/x86/xen.lds.S
> @@ -57,6 +57,10 @@ SECTIONS
> __image_base__ = .;
> #else
> . = __image_base__;
> + /DISCARD/ : {
> + *(.text.header)
> + *(.init.*multiboot)
> + }
> #endif
>
> #if 0
> @@ -195,6 +199,7 @@ SECTIONS
> DECL_SECTION(.init.text) {
> #endif
> _sinittext = .;
> + *(.init.multiboot)
> *(.init.text)
> *(.text.startup)
> _einittext = .;
> @@ -220,6 +225,7 @@ SECTIONS
> *(.init.rodata.cf_clobber)
> __initdata_cf_clobber_end = .;
>
> + *(.init.rodata.multiboot)
> *(.init.rodata)
> *(.init.rodata.*)
>
> @@ -234,6 +240,7 @@ SECTIONS
> *(.initcall1.init)
> __initcall_end = .;
>
> + *(.init.data.multiboot)
> *(.init.data)
> *(.init.data.rel)
> *(.init.data.rel.*)
> diff --git a/xen/tools/combine_two_binaries.py b/xen/tools/combine_two_binaries.py
> index 581e57cbc0..5f0433dcad 100755
> --- a/xen/tools/combine_two_binaries.py
> +++ b/xen/tools/combine_two_binaries.py
> @@ -33,7 +33,7 @@ parser.add_argument('--map', dest='mapfile',
> parser.add_argument('--exports', dest='exports',
> help='Symbols to export')
> parser.add_argument('--section-header', dest='section_header',
> - default='.section .init.text, "ax", @progbits',
> + default='.section .init.multiboot, "ax", @progbits',
> help='Section header declaration')
> parser.add_argument('-v', '--verbose',
> action='store_true')
> --
> 2.43.0
>
--
Best Regards,
Marek Marczykowski-Górecki
Invisible Things Lab
On 06.07.2026 12:45, Frediano Ziglio wrote: > From: Roger Pau Monné <roger.pau@citrix.com> > > Multiboot and PVH booting are not supported for PE, hence discards them > in the linker script when doing a PE build. > > That removes some relocations that otherwise appear due to the usage of the > start and __efi64_mb2_start symbols in the multiboot2 header. > > Section discarding is not done updating DISCARD_SECTIONS definition as the > change is specific for x86. > > No functional change intended. > > Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> > Signed-off-by: Frediano Ziglio <frediano.ziglio@citrix.com> Reviewed-by: Jan Beulich <jbeulich@suse.com>
© 2016 - 2026 Red Hat, Inc.