Merge branch 'topic/mem-encrypt' into next

This branch has some cross-arch patches that are a prequisite for the
SVM work. They're in a topic branch in case any of the other arch
maintainers want to merge them to resolve conflicts.

arch/Kconfig

@@ -925,6 +925,9 @@ config LOCK_EVENT_COUNTS
 	  the chance of application behavior change because of timing
 	  differences. The counts are reported via debugfs.
 
+config ARCH_HAS_MEM_ENCRYPT
+	bool
+
 source "kernel/gcov/Kconfig"
 
 source "scripts/gcc-plugins/Kconfig"

arch/s390/Kconfig

 # SPDX-License-Identifier: GPL-2.0
-config ARCH_HAS_MEM_ENCRYPT
-        def_bool y
-
 config MMU
 	def_bool y
 
@@ -68,6 +65,7 @@ config S390
 	select ARCH_HAS_GCOV_PROFILE_ALL
 	select ARCH_HAS_GIGANTIC_PAGE
 	select ARCH_HAS_KCOV
+	select ARCH_HAS_MEM_ENCRYPT
 	select ARCH_HAS_PTE_SPECIAL
 	select ARCH_HAS_SET_MEMORY
 	select ARCH_HAS_STRICT_KERNEL_RWX

arch/s390/include/asm/mem_encrypt.h

@@ -4,10 +4,7 @@
 
 #ifndef __ASSEMBLY__
 
-#define sme_me_mask	0ULL
-
-static inline bool sme_active(void) { return false; }
-extern bool sev_active(void);
+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);

arch/s390/mm/init.c

@@ -156,14 +156,9 @@ int set_memory_decrypted(unsigned long addr, int numpages)
 }
 
 /* are we a protected virtualization guest? */
-bool sev_active(void)
-{
-	return is_prot_virt_guest();
-}
-
 bool force_dma_unencrypted(struct device *dev)
 {
-	return sev_active();
+	return is_prot_virt_guest();
 }
 
 /* protected virtualization */

arch/x86/Kconfig

@@ -68,6 +68,7 @@ config X86
 	select ARCH_HAS_FORTIFY_SOURCE
 	select ARCH_HAS_GCOV_PROFILE_ALL
 	select ARCH_HAS_KCOV			if X86_64
+	select ARCH_HAS_MEM_ENCRYPT
 	select ARCH_HAS_MEMBARRIER_SYNC_CORE
 	select ARCH_HAS_PMEM_API		if X86_64
 	select ARCH_HAS_PTE_DEVMAP		if X86_64
@@ -1518,9 +1519,6 @@ config X86_CPA_STATISTICS
 	  helps to determine the effectiveness of preserving large and huge
 	  page mappings when mapping protections are changed.
 
-config ARCH_HAS_MEM_ENCRYPT
-	def_bool y
-
 config AMD_MEM_ENCRYPT
 	bool "AMD Secure Memory Encryption (SME) support"
 	depends on X86_64 && CPU_SUP_AMD

arch/x86/include/asm/mem_encrypt.h

@@ -92,6 +92,16 @@ early_set_memory_encrypted(unsigned long vaddr, unsigned long size) { return 0;
 
 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;
+}
+
 #endif	/* __ASSEMBLY__ */
 
 #endif	/* __X86_MEM_ENCRYPT_H__ */

arch/x86/kernel/crash_dump_64.c

@@ -70,3 +70,8 @@ ssize_t copy_oldmem_page_encrypted(unsigned long pfn, char *buf, size_t csize,
 {
 	return __copy_oldmem_page(pfn, buf, csize, offset, userbuf, true);
 }
+
+ssize_t elfcorehdr_read(char *buf, size_t count, u64 *ppos)
+{
+	return read_from_oldmem(buf, count, ppos, 0, sev_active());
+}

arch/x86/mm/mem_encrypt.c

@@ -344,13 +344,11 @@ bool sme_active(void)
 {
 	return sme_me_mask && !sev_enabled;
 }
-EXPORT_SYMBOL(sme_active);
 
 bool sev_active(void)
 {
 	return sme_me_mask && sev_enabled;
 }
-EXPORT_SYMBOL(sev_active);
 
 /* Override for DMA direct allocation check - ARCH_HAS_FORCE_DMA_UNENCRYPTED */
 bool force_dma_unencrypted(struct device *dev)

fs/proc/vmcore.c

@@ -104,9 +104,9 @@ static int pfn_is_ram(unsigned long pfn)
 }
 
 /* Reads a page from the oldmem device from given offset. */
-static ssize_t read_from_oldmem(char *buf, size_t count,
-				u64 *ppos, int userbuf,
-				bool encrypted)
+ssize_t read_from_oldmem(char *buf, size_t count,
+			 u64 *ppos, int userbuf,
+			 bool encrypted)
 {
 	unsigned long pfn, offset;
 	size_t nr_bytes;
@@ -170,7 +170,7 @@ void __weak elfcorehdr_free(unsigned long long addr)
  */
 ssize_t __weak elfcorehdr_read(char *buf, size_t count, u64 *ppos)
 {
-	return read_from_oldmem(buf, count, ppos, 0, sev_active());
+	return read_from_oldmem(buf, count, ppos, 0, false);
 }
 
 /*

include/linux/crash_dump.h

@@ -115,4 +115,18 @@ static inline int vmcore_add_device_dump(struct vmcoredd_data *data)
 	return -EOPNOTSUPP;
 }
 #endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */
+
+#ifdef CONFIG_PROC_VMCORE
+ssize_t read_from_oldmem(char *buf, size_t count,
+			 u64 *ppos, int userbuf,
+			 bool encrypted);
+#else
+static inline ssize_t read_from_oldmem(char *buf, size_t count,
+				       u64 *ppos, int userbuf,
+				       bool encrypted)
+{
+	return -EOPNOTSUPP;
+}
+#endif /* CONFIG_PROC_VMCORE */
+
 #endif /* LINUX_CRASHDUMP_H */

include/linux/mem_encrypt.h

@@ -18,23 +18,10 @@
 
 #else	/* !CONFIG_ARCH_HAS_MEM_ENCRYPT */
 
-#define sme_me_mask	0ULL
-
-static inline bool sme_active(void) { return false; }
-static inline bool sev_active(void) { return false; }
+static inline bool mem_encrypt_active(void) { return false; }
 
 #endif	/* CONFIG_ARCH_HAS_MEM_ENCRYPT */
 
-static inline bool mem_encrypt_active(void)
-{
-	return sme_me_mask;
-}
-
-static inline u64 sme_get_me_mask(void)
-{
-	return sme_me_mask;
-}
-
 #ifdef CONFIG_AMD_MEM_ENCRYPT
 /*
  * The __sme_set() and __sme_clr() macros are useful for adding or removing

kernel/dma/mapping.c

@@ -291,12 +291,6 @@ void dma_free_attrs(struct device *dev, size_t size, void *cpu_addr,
 }
 EXPORT_SYMBOL(dma_free_attrs);
 
-static inline void dma_check_mask(struct device *dev, u64 mask)
-{
-	if (sme_active() && (mask < (((u64)sme_get_me_mask() << 1) - 1)))
-		dev_warn(dev, "SME is active, device will require DMA bounce buffers\n");
-}
-
 int dma_supported(struct device *dev, u64 mask)
 {
 	const struct dma_map_ops *ops = get_dma_ops(dev);
@@ -327,7 +321,6 @@ int dma_set_mask(struct device *dev, u64 mask)
 		return -EIO;
 
 	arch_dma_set_mask(dev, mask);
-	dma_check_mask(dev, mask);
 	*dev->dma_mask = mask;
 	return 0;
 }
@@ -345,7 +338,6 @@ int dma_set_coherent_mask(struct device *dev, u64 mask)
 	if (!dma_supported(dev, mask))
 		return -EIO;
 
-	dma_check_mask(dev, mask);
 	dev->coherent_dma_mask = mask;
 	return 0;
 }

kernel/dma/swiotlb.c

@@ -461,8 +461,7 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev,
 		panic("Can not allocate SWIOTLB buffer earlier and can't now provide you with the DMA bounce buffer");
 
 	if (mem_encrypt_active())
-		pr_warn_once("%s is active and system is using DMA bounce buffers\n",
-			     sme_active() ? "SME" : "SEV");
+		pr_warn_once("Memory encryption is active and system is using DMA bounce buffers\n");
 
 	mask = dma_get_seg_boundary(hwdev);