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From: Thiago Jung Bauermann <bauerman@linux.ibm.com>
To: x86@kernel.org
Cc: linux-s390@vger.kernel.org,
	Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
	Robin Murphy <robin.murphy@arm.com>,
	Mike Anderson <andmike@linux.ibm.com>,
	Ram Pai <linuxram@us.ibm.com>,
	linux-kernel@vger.kernel.org,
	Alexey Dobriyan <adobriyan@gmail.com>,
	Halil Pasic <pasic@linux.ibm.com>,
	iommu@lists.linux-foundation.org, Ingo Molnar <mingo@redhat.com>,
	Borislav Petkov <bp@alien8.de>,
	Thomas Lendacky <Thomas.Lendacky@amd.com>,
	"H. Peter Anvin" <hpa@zytor.com>,
	linux-fsdevel@vger.kernel.org,
	Thomas Gleixner <tglx@linutronix.de>,
	linuxppc-dev@lists.ozlabs.org, Christoph Hellwig <hch@lst.de>
Subject: [PATCH 3/3] fs/core/vmcore: Move sev_active() reference to x86 arch code
Date: Sat, 13 Jul 2019 01:45:54 -0300
Message-ID: <20190713044554.28719-4-bauerman@linux.ibm.com> (raw)
In-Reply-To: <20190713044554.28719-1-bauerman@linux.ibm.com>

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.

Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
---
 arch/x86/kernel/crash_dump_64.c |  5 +++++
 fs/proc/vmcore.c                |  8 ++++----
 include/linux/crash_dump.h      | 14 ++++++++++++++
 include/linux/mem_encrypt.h     |  1 -
 4 files changed, 23 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kernel/crash_dump_64.c b/arch/x86/kernel/crash_dump_64.c
index 22369dd5de3b..045e82e8945b 100644
--- 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/fs/proc/vmcore.c b/fs/proc/vmcore.c
index 57957c91c6df..ca1f20bedd8c 100644
--- a/fs/proc/vmcore.c
+++ b/fs/proc/vmcore.c
@@ -100,9 +100,9 @@ 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;
@@ -166,7 +166,7 @@ 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 f774c5eb9e3c..4664fc1871de 100644
--- 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 0c5b0ff9eb29..5c4a18a91f89 100644
--- 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 */
 

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  parent reply index

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-07-13  4:45 [PATCH 0/3] Remove x86-specific code from generic headers Thiago Jung Bauermann
2019-07-13  4:45 ` [PATCH 1/3] x86, s390: Move ARCH_HAS_MEM_ENCRYPT definition to arch/Kconfig Thiago Jung Bauermann
2019-07-13  7:27   ` [PATCH 1/3] x86,s390: " Christoph Hellwig
2019-07-15 15:23   ` [PATCH 1/3] x86, s390: " janani
2019-07-15 20:00     ` Thiago Jung Bauermann
2019-07-13  4:45 ` [PATCH 2/3] DMA mapping: Move SME handling to x86-specific files Thiago Jung Bauermann
2019-07-13  7:29   ` Christoph Hellwig
2019-07-13  4:45 ` Thiago Jung Bauermann [this message]
2019-07-13  5:08 ` [PATCH 0/3] Remove x86-specific code from generic headers Thiago Jung Bauermann
  -- strict thread matches above, loose matches on Subject: below --
2019-07-12  5:36 Thiago Jung Bauermann
2019-07-12  5:36 ` [PATCH 3/3] fs/core/vmcore: Move sev_active() reference to x86 arch code Thiago Jung Bauermann
2019-07-12 13:09   ` Halil Pasic
2019-07-12 14:08     ` Christoph Hellwig
2019-07-12 14:51       ` Halil Pasic
2019-07-12 15:11         ` Christoph Hellwig
2019-07-12 15:42           ` Halil Pasic
2019-07-13  8:08             ` Christoph Hellwig
2019-07-12 21:55     ` Thiago Jung Bauermann
2019-07-15 14:03       ` Halil Pasic
2019-07-15 14:30         ` Christoph Hellwig
2019-07-15 15:44           ` Lendacky, Thomas
2019-07-15 20:14           ` Thiago Jung Bauermann

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