[PATCH v5 4/6] x86/boot: Move SEV startup code into startup/

From: Ard Biesheuvel
Date: Fri Apr 18 2025 - 10:15:03 EST


From: Ard Biesheuvel <ardb@xxxxxxxxxx>

Move the SEV startup code into arch/x86/boot/startup/, where it will
reside along with other code that executes extremely early, and
therefore needs to be built in a special manner.

Signed-off-by: Ard Biesheuvel <ardb@xxxxxxxxxx>
---
arch/x86/boot/compressed/sev.c | 2 +-
arch/x86/boot/startup/Makefile | 2 +-
arch/x86/{coco/sev/shared.c => boot/startup/sev-shared.c} | 0
arch/x86/{coco/sev/startup.c => boot/startup/sev-startup.c} | 2 +-
arch/x86/coco/sev/Makefile | 20 ++------------------
5 files changed, 5 insertions(+), 21 deletions(-)

diff --git a/arch/x86/boot/compressed/sev.c b/arch/x86/boot/compressed/sev.c
index 714e30c66eae..478c65149cf0 100644
--- a/arch/x86/boot/compressed/sev.c
+++ b/arch/x86/boot/compressed/sev.c
@@ -144,7 +144,7 @@ int svsm_perform_call_protocol(struct svsm_call *call);
u8 snp_vmpl;

/* Include code for early handlers */
-#include "../../coco/sev/shared.c"
+#include "../../boot/startup/sev-shared.c"

int svsm_perform_call_protocol(struct svsm_call *call)
{
diff --git a/arch/x86/boot/startup/Makefile b/arch/x86/boot/startup/Makefile
index bb7c826e586c..21d911b61459 100644
--- a/arch/x86/boot/startup/Makefile
+++ b/arch/x86/boot/startup/Makefile
@@ -17,7 +17,7 @@ UBSAN_SANITIZE := n
KCOV_INSTRUMENT := n

obj-$(CONFIG_X86_64) += gdt_idt.o map_kernel.o
-obj-$(CONFIG_AMD_MEM_ENCRYPT) += sme.o
+obj-$(CONFIG_AMD_MEM_ENCRYPT) += sme.o sev-startup.o

lib-$(CONFIG_X86_64) += la57toggle.o
lib-$(CONFIG_EFI_MIXED) += efi-mixed.o
diff --git a/arch/x86/coco/sev/shared.c b/arch/x86/boot/startup/sev-shared.c
similarity index 100%
rename from arch/x86/coco/sev/shared.c
rename to arch/x86/boot/startup/sev-shared.c
diff --git a/arch/x86/coco/sev/startup.c b/arch/x86/boot/startup/sev-startup.c
similarity index 99%
rename from arch/x86/coco/sev/startup.c
rename to arch/x86/boot/startup/sev-startup.c
index 9f5dc70cfb44..10b636009d1c 100644
--- a/arch/x86/coco/sev/startup.c
+++ b/arch/x86/boot/startup/sev-startup.c
@@ -422,7 +422,7 @@ static __always_inline void vc_forward_exception(struct es_em_ctxt *ctxt)
}

/* Include code shared with pre-decompression boot stage */
-#include "shared.c"
+#include "sev-shared.c"

noinstr void __sev_put_ghcb(struct ghcb_state *state)
{
diff --git a/arch/x86/coco/sev/Makefile b/arch/x86/coco/sev/Makefile
index 57e25f946663..2919dcfc4b02 100644
--- a/arch/x86/coco/sev/Makefile
+++ b/arch/x86/coco/sev/Makefile
@@ -1,25 +1,9 @@
# SPDX-License-Identifier: GPL-2.0

-obj-y += core.o sev-nmi.o startup.o
-
-# jump tables are emitted using absolute references in non-PIC code
-# so they cannot be used in the early SEV startup code
-CFLAGS_startup.o += -fno-jump-tables
-
-ifdef CONFIG_FUNCTION_TRACER
-CFLAGS_REMOVE_startup.o = -pg
-endif
-
-KASAN_SANITIZE_startup.o := n
-KMSAN_SANITIZE_startup.o := n
-KCOV_INSTRUMENT_startup.o := n
-
-# With some compiler versions the generated code results in boot hangs, caused
-# by several compilation units. To be safe, disable all instrumentation.
-KCSAN_SANITIZE := n
+obj-y += core.o sev-nmi.o

# Clang 14 and older may fail to respect __no_sanitize_undefined when inlining
-UBSAN_SANITIZE := n
+UBSAN_SANITIZE_sev-nmi.o := n

# GCC may fail to respect __no_sanitize_address when inlining
KASAN_SANITIZE_sev-nmi.o := n
--
2.49.0.805.g082f7c87e0-goog