treewide: Replace the use of mem_encrypt_active() with cc_platform_has()

Replace uses of mem_encrypt_active() with calls to cc_platform_has() with
the CC_ATTR_MEM_ENCRYPT attribute.

Remove the implementation of mem_encrypt_active() across all arches.

For s390, since the default implementation of the cc_platform_has()
matches the s390 implementation of mem_encrypt_active(), cc_platform_has()
does not need to be implemented in s390 (the config option
ARCH_HAS_CC_PLATFORM is not set).

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210928191009.32551-9-bp@alien8.de

8 files changed, 15 insertions, 20 deletions

diff --git a/arch/powerpc/include/asm/mem_encrypt.h b/arch/powerpc/include/asm/mem_encrypt.h
index ba9dab07c1be..2f26b8fc8d29 100644
--- a/arch/powerpc/include/asm/mem_encrypt.h
+++ b/arch/powerpc/include/asm/mem_encrypt.h
@@ -10,11 +10,6 @@
 
 #include <asm/svm.h>
 
-static inline bool mem_encrypt_active(void)
-{
-	return is_secure_guest();
-}
-
 static inline bool force_dma_unencrypted(struct device *dev)
 {
 	return is_secure_guest();
diff --git a/arch/powerpc/platforms/pseries/svm.c b/arch/powerpc/platforms/pseries/svm.c
index 87f001b4c4e4..c083ecbbae4d 100644
--- a/arch/powerpc/platforms/pseries/svm.c
+++ b/arch/powerpc/platforms/pseries/svm.c
@@ -8,6 +8,7 @@
 
 #include <linux/mm.h>
 #include <linux/memblock.h>
+#include <linux/cc_platform.h>
 #include <asm/machdep.h>
 #include <asm/svm.h>
 #include <asm/swiotlb.h>
@@ -63,7 +64,7 @@ void __init svm_swiotlb_init(void)
 
 int set_memory_encrypted(unsigned long addr, int numpages)
 {
-	if (!mem_encrypt_active())
+	if (!cc_platform_has(CC_ATTR_MEM_ENCRYPT))
 		return 0;
 
 	if (!PAGE_ALIGNED(addr))
@@ -76,7 +77,7 @@ int set_memory_encrypted(unsigned long addr, int numpages)
 
 int set_memory_decrypted(unsigned long addr, int numpages)
 {
-	if (!mem_encrypt_active())
+	if (!cc_platform_has(CC_ATTR_MEM_ENCRYPT))
 		return 0;
 
 	if (!PAGE_ALIGNED(addr))
diff --git a/arch/s390/include/asm/mem_encrypt.h b/arch/s390/include/asm/mem_encrypt.h
index 2542cbf7e2d1..08a8b96606d7 100644
--- a/arch/s390/include/asm/mem_encrypt.h
+++ b/arch/s390/include/asm/mem_encrypt.h
@@ -4,8 +4,6 @@
 
 #ifndef __ASSEMBLY__
 
-static inline bool mem_encrypt_active(void) { return false; }
-
 int set_memory_encrypted(unsigned long addr, int numpages);
 int set_memory_decrypted(unsigned long addr, int numpages);
 
diff --git a/arch/x86/include/asm/mem_encrypt.h b/arch/x86/include/asm/mem_encrypt.h
index da14ede311aa..2d4f5c17d79c 100644
--- a/arch/x86/include/asm/mem_encrypt.h
+++ b/arch/x86/include/asm/mem_encrypt.h
@@ -96,11 +96,6 @@ static inline void mem_encrypt_free_decrypted_mem(void) { }
 
 extern char __start_bss_decrypted[], __end_bss_decrypted[], __start_bss_decrypted_unused[];
 
-static inline bool mem_encrypt_active(void)
-{
-	return sme_me_mask;
-}
-
 static inline u64 sme_get_me_mask(void)
 {
 	return sme_me_mask;
diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index de01903c3735..fc5371a7e9d1 100644
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -19,7 +19,7 @@
 #include <linux/start_kernel.h>
 #include <linux/io.h>
 #include <linux/memblock.h>
-#include <linux/mem_encrypt.h>
+#include <linux/cc_platform.h>
 #include <linux/pgtable.h>
 
 #include <asm/processor.h>
@@ -284,8 +284,13 @@ unsigned long __head __startup_64(unsigned long physaddr,
 	 * The bss section will be memset to zero later in the initialization so
 	 * there is no need to zero it after changing the memory encryption
 	 * attribute.
+	 *
+	 * This is early code, use an open coded check for SME instead of
+	 * using cc_platform_has(). This eliminates worries about removing
+	 * instrumentation or checking boot_cpu_data in the cc_platform_has()
+	 * function.
 	 */
-	if (mem_encrypt_active()) {
+	if (sme_get_me_mask()) {
 		vaddr = (unsigned long)__start_bss_decrypted;
 		vaddr_end = (unsigned long)__end_bss_decrypted;
 		for (; vaddr < vaddr_end; vaddr += PMD_SIZE) {
diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
index b59a5cbc6bc5..026031b3b782 100644
--- a/arch/x86/mm/ioremap.c
+++ b/arch/x86/mm/ioremap.c
@@ -694,7 +694,7 @@ static bool __init early_memremap_is_setup_data(resource_size_t phys_addr,
 bool arch_memremap_can_ram_remap(resource_size_t phys_addr, unsigned long size,
 				 unsigned long flags)
 {
-	if (!mem_encrypt_active())
+	if (!cc_platform_has(CC_ATTR_MEM_ENCRYPT))
 		return true;
 
 	if (flags & MEMREMAP_ENC)
@@ -724,7 +724,7 @@ pgprot_t __init early_memremap_pgprot_adjust(resource_size_t phys_addr,
 {
 	bool encrypted_prot;
 
-	if (!mem_encrypt_active())
+	if (!cc_platform_has(CC_ATTR_MEM_ENCRYPT))
 		return prot;
 
 	encrypted_prot = true;
diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
index 2d04c39bea1d..23d54b810f08 100644
--- a/arch/x86/mm/mem_encrypt.c
+++ b/arch/x86/mm/mem_encrypt.c
@@ -400,7 +400,7 @@ void __init mem_encrypt_free_decrypted_mem(void)
 	 * The unused memory range was mapped decrypted, change the encryption
 	 * attribute from decrypted to encrypted before freeing it.
 	 */
-	if (mem_encrypt_active()) {
+	if (cc_platform_has(CC_ATTR_MEM_ENCRYPT)) {
 		r = set_memory_encrypted(vaddr, npages);
 		if (r) {
 			pr_warn("failed to free unused decrypted pages\n");
diff --git a/arch/x86/mm/pat/set_memory.c b/arch/x86/mm/pat/set_memory.c
index ad8a5c586a35..527957586f3c 100644
--- a/arch/x86/mm/pat/set_memory.c
+++ b/arch/x86/mm/pat/set_memory.c
@@ -18,6 +18,7 @@
 #include <linux/libnvdimm.h>
 #include <linux/vmstat.h>
 #include <linux/kernel.h>
+#include <linux/cc_platform.h>
 
 #include <asm/e820/api.h>
 #include <asm/processor.h>
@@ -1986,7 +1987,7 @@ static int __set_memory_enc_dec(unsigned long addr, int numpages, bool enc)
 	int ret;
 
 	/* Nothing to do if memory encryption is not active */
-	if (!mem_encrypt_active())
+	if (!cc_platform_has(CC_ATTR_MEM_ENCRYPT))
 		return 0;
 
 	/* Should not be working on unaligned addresses */