x86/sev: Disable ftrace branch profiling in SEV startup code

Ftrace branch profiling inserts absolute references to its metadata at
call sites, and this implies that this kind of instrumentation cannot be
used while executing from the 1:1 mapping of memory.

Therefore, disable ftrace branch profiling in the SEV startup routines,
by disabling it for the entire SEV core source file.

Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/
Reported-by: kernel test robot <[email protected]>
Signed-off-by: Ard Biesheuvel <[email protected]>
Signed-off-by: Borislav Petkov (AMD) <[email protected]>
Acked-by: Tom Lendacky <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

Author: ardbiesheuvel

arch/x86/coco/sev/core.c

@@ -9,6 +9,8 @@
 
 #define pr_fmt(fmt)	"SEV: " fmt
 
+#define DISABLE_BRANCH_PROFILING
+
 #include <linux/sched/debug.h>	/* For show_regs() */
 #include <linux/percpu-defs.h>
 #include <linux/cc_platform.h>