Re: [PATCH v5 08/10] arm64: realm: Move Realm memory encryption ops to RSI code

Realm memory encryption callbacks are CCA-specific. Keep the Realm callback
registration with the RSI initialization code instead of pageattr.c, which
only needs to provide the low-level page-attribute transition helper.

Export __set_memory_enc_dec() within arm64 so the RSI code can wrap it with
the Realm-specific encrypt/decrypt callbacks and warning policy.

No functional changes in this patch.

Signed-off-by: Aneesh Kumar K.V (Arm) <aneesh.kumar@kernel.org>
---
 arch/arm64/include/asm/mem_encrypt.h |  3 +--
 arch/arm64/kernel/rsi.c              | 34 +++++++++++++++++++++++++
 arch/arm64/mm/pageattr.c             | 38 +---------------------------
 3 files changed, 36 insertions(+), 39 deletions(-)

diff --git a/arch/arm64/include/asm/mem_encrypt.h b/arch/arm64/include/asm/mem_encrypt.h
index 314b2b52025f..f6325f30e844 100644
--- a/arch/arm64/include/asm/mem_encrypt.h
+++ b/arch/arm64/include/asm/mem_encrypt.h

@@ -15,8 +15,7 @@ int arm64_mem_crypt_ops_register(const struct arm64_mem_crypt_ops *ops);
 
 int set_memory_encrypted(unsigned long addr, int numpages);
 int set_memory_decrypted(unsigned long addr, int numpages);
-
-int realm_register_memory_enc_ops(void);
+int __set_memory_enc_dec(unsigned long addr, int numpages, bool encrypt);
 
 static inline bool force_dma_unencrypted(struct device *dev)
 {

diff --git a/arch/arm64/kernel/rsi.c b/arch/arm64/kernel/rsi.c
index 1fb2abd79800..5c566700974c 100644
--- a/arch/arm64/kernel/rsi.c
+++ b/arch/arm64/kernel/rsi.c

@@ -143,6 +143,40 @@ static int realm_ioremap_hook(phys_addr_t phys, size_t size, pgprot_t *prot)
 	return 0;
 }
 
+static int realm_set_memory_encrypted(unsigned long addr, int numpages)
+{
+	int ret = __set_memory_enc_dec(addr, numpages, true);
+
+	/*
+	 * If the request to change state fails, then the only sensible cause
+	 * of action for the caller is to leak the memory
+	 */
+	WARN(ret, "Failed to encrypt memory, %d pages will be leaked",
+	     numpages);
+
+	return ret;
+}
+
+static int realm_set_memory_decrypted(unsigned long addr, int numpages)
+{
+	int ret = __set_memory_enc_dec(addr, numpages, false);
+
+	WARN(ret, "Failed to decrypt memory, %d pages will be leaked",
+	     numpages);
+
+	return ret;
+}
+
+static const struct arm64_mem_crypt_ops realm_crypt_ops = {
+	.encrypt = realm_set_memory_encrypted,
+	.decrypt = realm_set_memory_decrypted,
+};
+
+static int realm_register_memory_enc_ops(void)
+{
+	return arm64_mem_crypt_ops_register(&realm_crypt_ops);
+}