From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <tglx@linutronix.de>
Date: Wed, 14 Jun 2023 01:39:41 +0200
Subject: [PATCH] init, x86: Move mem_encrypt_init() into
 arch_cpu_finalize_init()

Invoke the X86ism mem_encrypt_init() from X86 arch_cpu_finalize_init() and
remove the weak fallback from the core code.

No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20230613224545.670360645@linutronix.de

(backported from commit 439e17576eb47f26b78c5bbc72e344d4206d2327)
[cascardo: really remove mem_encrypt_init from init/main.c]
CVE-2022-40982
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Acked-by: Roxana Nicolescu <roxana.nicolescu@canonical.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
(cherry picked from commit 439b49f26bc9ee74a3ac4b356c12d41f68c49cbd)
Signed-off-by: Stoiko Ivanov <s.ivanov@proxmox.com>
---
 arch/x86/include/asm/mem_encrypt.h |  7 ++++---
 arch/x86/kernel/cpu/common.c       | 11 +++++++++++
 init/main.c                        | 11 -----------
 3 files changed, 15 insertions(+), 14 deletions(-)

diff --git a/arch/x86/include/asm/mem_encrypt.h b/arch/x86/include/asm/mem_encrypt.h
index 72ca90552b6a..a95914f479b8 100644
--- a/arch/x86/include/asm/mem_encrypt.h
+++ b/arch/x86/include/asm/mem_encrypt.h
@@ -51,6 +51,8 @@ void __init mem_encrypt_free_decrypted_mem(void);
 
 void __init sev_es_init_vc_handling(void);
 
+void __init mem_encrypt_init(void);
+
 #define __bss_decrypted __section(".bss..decrypted")
 
 #else	/* !CONFIG_AMD_MEM_ENCRYPT */
@@ -82,13 +84,12 @@ early_set_mem_enc_dec_hypercall(unsigned long vaddr, int npages, bool enc) {}
 
 static inline void mem_encrypt_free_decrypted_mem(void) { }
 
+static inline void mem_encrypt_init(void) { }
+
 #define __bss_decrypted
 
 #endif	/* CONFIG_AMD_MEM_ENCRYPT */
 
-/* Architecture __weak replacement functions */
-void __init mem_encrypt_init(void);
-
 void add_encrypt_protection_map(void);
 
 /*
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 0f32ecfbdeb1..637817d0d819 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -18,6 +18,7 @@
 #include <linux/init.h>
 #include <linux/kprobes.h>
 #include <linux/kgdb.h>
+#include <linux/mem_encrypt.h>
 #include <linux/smp.h>
 #include <linux/cpu.h>
 #include <linux/io.h>
@@ -2412,4 +2413,14 @@ void __init arch_cpu_finalize_init(void)
 	} else {
 		fpu__init_check_bugs();
 	}
+
+	/*
+	 * This needs to be called before any devices perform DMA
+	 * operations that might use the SWIOTLB bounce buffers. It will
+	 * mark the bounce buffers as decrypted so that their usage will
+	 * not cause "plain-text" data to be decrypted when accessed. It
+	 * must be called after late_time_init() so that Hyper-V x86/x64
+	 * hypercalls work when the SWIOTLB bounce buffers are decrypted.
+	 */
+	mem_encrypt_init();
 }
diff --git a/init/main.c b/init/main.c
index 967584e8c3af..7533b4da4fb2 100644
--- a/init/main.c
+++ b/init/main.c
@@ -96,7 +96,6 @@
 #include <linux/cache.h>
 #include <linux/rodata_test.h>
 #include <linux/jump_label.h>
-#include <linux/mem_encrypt.h>
 #include <linux/kcsan.h>
 #include <linux/init_syscalls.h>
 #include <linux/stackdepot.h>
@@ -783,8 +782,6 @@ void __init __weak thread_stack_cache_init(void)
 }
 #endif
 
-void __init __weak mem_encrypt_init(void) { }
-
 void __init __weak poking_init(void) { }
 
 void __init __weak pgtable_cache_init(void) { }
@@ -1087,14 +1084,6 @@ asmlinkage __visible void __init __no_sanitize_address start_kernel(void)
 	 */
 	locking_selftest();
 
-	/*
-	 * This needs to be called before any devices perform DMA
-	 * operations that might use the SWIOTLB bounce buffers. It will
-	 * mark the bounce buffers as decrypted so that their usage will
-	 * not cause "plain-text" data to be decrypted when accessed.
-	 */
-	mem_encrypt_init();
-
 #ifdef CONFIG_BLK_DEV_INITRD
 	if (initrd_start && !initrd_below_start_ok &&
 	    page_to_pfn(virt_to_page((void *)initrd_start)) < min_low_pfn) {