[PATCH v2] x86/setup: do not include kexec_handover.h from asm/setup.h

[Pratyush Yadav]

On Fri, Jul 03 2026, Borislav Petkov wrote:

> On Fri, Jul 03, 2026 at 04:37:03PM +0200, Pratyush Yadav wrote:
>> From: "Pratyush Yadav (Google)" <pratyush at kernel.org>
>> 
>> x86 asm/setup.h includes linux/kexec_handover.h. This is because it is
>> used by setup.c and kaslr.c. But this inclusion is problematic. The
>> header is included in many places, so it results in the KHO header being
>> propagated there. Also, the setup header is used by realmode code. If
>> KHO header includes things like mm.h, it causes a big dump of
>> compliation failures.
>
>> Nothing in setup.h uses anything from KHO. Remove the header from
>> setup.h, and directly include it in setup.c. which does use things from
>> KHO. Since kaslr.c is a part of the decompressor, avoid including linux
>> headers there directly. Instead, split out struct kho_scratch, which is
>> the only thing the kaslr.c uses, and move it to
>> include/asm-generic/kexec_handover.h.
>> 
>> This change should also help reduce files recompiled when
>
>> kexec_handover.h changes.
>> 
>> Signed-off-by: Pratyush Yadav (Google) <pratyush at kernel.org>
>> ---
>> 
>> Notes:
>>     Thomas/Ingo/Borislav/Dave, is it okay if we take this patch through the
>
> See my reply to Mike about using the generic-y infrastructure.

To double check I got your point correctly, is this what you mean?

diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c
index ac02aed8757b..22267a83e064 100644
--- a/arch/x86/boot/compressed/kaslr.c
+++ b/arch/x86/boot/compressed/kaslr.c
@@ -32,7 +32,7 @@
 #include <asm/setup.h>	/* For COMMAND_LINE_SIZE */
 #undef _SETUP
 
-#include <asm-generic/kexec_handover.h>
+#include <asm/kexec_handover.h>
 
 extern unsigned long get_cmd_line_ptr(void);
 
diff --git a/arch/x86/include/asm/Kbuild b/arch/x86/include/asm/Kbuild
index 078fd2c0d69d..47ef8cb482e3 100644
--- a/arch/x86/include/asm/Kbuild
+++ b/arch/x86/include/asm/Kbuild
@@ -15,3 +15,4 @@ generic-y += fprobe.h
 generic-y += mcs_spinlock.h
 generic-y += mmzone.h
 generic-y += ring_buffer.h
+generic-y += kexec_handover.h

-- 
Regards,
Pratyush Yadav