Commit ae7eb82a authored by Thiago Jung Bauermann's avatar Thiago Jung Bauermann Committed by Michael Ellerman
Browse files

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: default avatarThiago Jung Bauermann <bauerman@linux.ibm.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarLianbo Jiang <lijiang@redhat.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190806044919.10622-6-bauerman@linux.ibm.com
parent 284e21fa

arch/x86/kernel/crash_dump_64.c

+5 −0
Original line number Diff line number Diff line
@@ -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

+0 −1
Original line number Diff line number Diff line
@@ -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)

fs/proc/vmcore.c

+4 −4
Original line number Diff line number Diff line
@@ -104,7 +104,7 @@ 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,

ssize_t read_from_oldmem(char *buf, size_t count,

			 u64 *ppos, int userbuf,

			 bool encrypted)

{
@@ -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

+14 −0
Original line number Diff line number Diff line
@@ -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

+0 −1
Original line number Diff line number Diff line
@@ -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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