[PATCH v2 2/6] percpu: Bound decrypted storage for all x86 encrypted guests

[Zack Rusin <zack.rusin@broadcom.com>]

TDX also needs shared per-CPU buffers. Use X86_MEM_ENCRYPT for their
definition and placement, and provide page-aligned boundaries so the
architecture can convert each CPU's whole section before registration.

Define the boundaries in the SMP template or UP data as appropriate.
Drop the unused DECLARE_PER_CPU_DECRYPTED() macro.

Suggested-by: Kiryl Shutsemau <kas@kernel.org>
Link: https://lore.kernel.org/r/aqqGUAX65s4LdJkr@thinkstation
Signed-off-by: Zack Rusin <zack.rusin@broadcom.com>
---
 include/asm-generic/vmlinux.lds.h | 12 ++++++++----
 include/linux/percpu-defs.h       |  7 ++-----
 2 files changed, 10 insertions(+), 9 deletions(-)

diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index 64bc2bfdd2ec..145fcdbbe9db 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -368,11 +368,13 @@
 /*
  * .data section
  */
-#if defined(CONFIG_AMD_MEM_ENCRYPT) && !defined(CONFIG_SMP)
+#if defined(CONFIG_X86_MEM_ENCRYPT) && !defined(CONFIG_SMP)
 #define DATA_DECRYPTED							\
 	. = ALIGN(PAGE_SIZE);						\
+	__start_percpu_decrypted = .;					\
 	*(.data..decrypted)						\
-	. = ALIGN(PAGE_SIZE);
+	. = ALIGN(PAGE_SIZE);						\
+	__end_percpu_decrypted = .;
 #else
 #define DATA_DECRYPTED	*(.data..decrypted)
 #endif
@@ -1022,11 +1024,13 @@
  * Note: We use a separate section so that only this section gets
  * decrypted to avoid exposing more than we wish.
  */
-#ifdef CONFIG_AMD_MEM_ENCRYPT
+#if defined(CONFIG_X86_MEM_ENCRYPT) && defined(CONFIG_SMP)
 #define PERCPU_DECRYPTED_SECTION					\
 	. = ALIGN(PAGE_SIZE);						\
+	__start_percpu_decrypted = .;					\
 	*(.data..percpu..decrypted)					\
-	. = ALIGN(PAGE_SIZE);
+	. = ALIGN(PAGE_SIZE);						\
+	__end_percpu_decrypted = .;
 #else
 #define PERCPU_DECRYPTED_SECTION
 #endif
diff --git a/include/linux/percpu-defs.h b/include/linux/percpu-defs.h
index dbe3267a0a13..fdb666a1b4de 100644
--- a/include/linux/percpu-defs.h
+++ b/include/linux/percpu-defs.h
@@ -169,13 +169,10 @@
 	DEFINE_PER_CPU_SECTION(type, name, "..read_mostly")
 
 /*
- * Declaration/definition used for per-CPU variables that should be accessed
+ * Definition used for built-in per-CPU variables that should be accessed
  * as decrypted when memory encryption is enabled in the guest.
  */
-#ifdef CONFIG_AMD_MEM_ENCRYPT
-#define DECLARE_PER_CPU_DECRYPTED(type, name)				\
-	DECLARE_PER_CPU_SECTION(type, name, "..decrypted")
-
+#ifdef CONFIG_X86_MEM_ENCRYPT
 #define DEFINE_PER_CPU_DECRYPTED(type, name)				\
 	DEFINE_PER_CPU_SECTION(type, name, "..decrypted")
 #else
-- 
2.53.0