fs/core/vmcore: Move sev_active() reference to x86 arch code

Secure Encrypted Virtualization is an x86-specific feature, so it shouldn't
appear in generic kernel code because it forces non-x86 architectures to
define the sev_active() function, which doesn't make a lot of sense.

To solve this problem, add an x86 elfcorehdr_read() function to override
the generic weak implementation. To do that, it's necessary to make
read_from_oldmem() public so that it can be used outside of vmcore.c.

Also, remove the export for sev_active() since it's only used in files that
won't be built as modules.

Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Lianbo Jiang <lijiang@redhat.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190806044919.10622-6-bauerman@linux.ibm.com

diff --git a/arch/x86/kernel/crash_dump_64.c b/arch/x86/kernel/crash_dump_64.c
index 22369dd5de3b87788dededb535bdf991cfdb3cb6..045e82e8945b3687e52d51bef8d59f5f2240e363 100644 (file)
--- a/arch/x86/kernel/crash_dump_64.c
+++ b/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());
+}

diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
index 94da5a88abe6215224f3519e5ddf9ac01faf85ea..9268c12458c848f2f3f1ebc75fd66ea514a6027b 100644 (file)
--- a/arch/x86/mm/mem_encrypt.c
+++ b/arch/x86/mm/mem_encrypt.c
@@ -349,7 +349,6 @@ 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)

diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c
index 7bcc92add72c1f1559e48eed956a58ec91ac824e..7b13988796e173ac170af460d6f4de299443b5d3 100644 (file)
--- a/fs/proc/vmcore.c
+++ b/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);
 }
 
 /*

diff --git a/include/linux/crash_dump.h b/include/linux/crash_dump.h
index f774c5eb9e3ccbde2fb32d8bb78a0b029c0a4c5c..4664fc1871de68606995e4c998d710bf278e572e 100644 (file)
--- a/include/linux/crash_dump.h
+++ b/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 */

diff --git a/include/linux/mem_encrypt.h b/include/linux/mem_encrypt.h
index 0c5b0ff9eb2992f51799e0c1222bf2a1959a03a8..5c4a18a91f898502e3eae8b5521999b245a27136 100644 (file)
--- a/include/linux/mem_encrypt.h
+++ b/include/linux/mem_encrypt.h
@@ -19,7 +19,6 @@
 #else  /* !CONFIG_ARCH_HAS_MEM_ENCRYPT */
 
 static inline bool mem_encrypt_active(void) { return false; }
-static inline bool sev_active(void) { return false; }
 
 #endif /* CONFIG_ARCH_HAS_MEM_ENCRYPT */