On Wed, 4 Oct 2023 16:54:20 -0600 Dan Raymond <raymod2@xxxxxxxxx> wrote: > With one exception io.h is included from boot.h or misc.h which is where > the include guards are defined: > > # find arch/x86/boot -type f -print0 | xargs -0 grep "#include.*[^a-z]io\.h" > arch/x86/boot/boot.h:#include "io.h" > arch/x86/boot/compressed/misc.h:#include "../io.h" > arch/x86/boot/compressed/tdx.c:#include "../io.h" > arch/x86/boot/io.h:#include <asm/shared/io.h> > > I agree this is fragile but the problem is not confined to this patch. > If I add a call to rdmsr() or wrmsr() in arch/x86/boot/compressed/misc.c > I get the same compiler error. It has something to do with the inline > assembly inside arch/x86/include/asm/jump_label.h. Doesn't arch/x86/boot/* code create an image that is separate from the core vmlinux? That is, that code doesn't implement jump label logic nor sections. > > I've copied Steven Rostedt who is the maintainer of tracefs to see if he > has any comment. I just noticed arch/x86/boot/msr.h and I see that it > redefines rdmsr() and wrmsr() and omits the tracepoints. A comment there > explains: > > /* > * The kernel proper already defines rdmsr()/wrmsr(), but they are not for the > * boot kernel since they rely on tracepoint/exception handling infrastructure > * that's not available here. > */ > > We could do something similar for inb()/outb() and redefine them in > arch/x86/boot/io.h instead of including <asm/shared/io.h> there. That would be a saner approach. -- Steve
