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/202501072244.zZrx9864-lkp@intel.com/
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Tom Lendacky <thomas.lendacky@amd.com>
Link: https://lore.kernel.org/r/20250107151826.820147-2-ardb+git@google.com

diff --git a/arch/x86/coco/sev/core.c b/arch/x86/coco/sev/core.c
index 86898547056e71e388edf525b03997cdd4584808..b5c6c4afd1cc6e8afd8dd3e388786981182ced67 100644 (file)
--- a/arch/x86/coco/sev/core.c
+++ b/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>