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

Author: KAGA-KOKO

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 */
@@ -83,13 +85,12 @@ 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);
 
 /*

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>
@@ -2414,4 +2415,14 @@ 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();
 }

init/main.c

@@ -95,7 +95,6 @@
 #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>
@@ -786,8 +785,6 @@ 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) { }
@@ -1043,16 +1040,6 @@ asmlinkage __visible void __init __no_sanitize_address __noreturn start_kernel(v
 
 	arch_cpu_finalize_init();
 
-	/*
-	 * 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();
-
 	pid_idr_init();
 	anon_vma_init();
 #ifdef CONFIG_X86