[PATCH 1/8] x86/ioremap: Selectively build arch override encryption functions

Borislav Petkov
2021-09-28T19:10:45Z

From: Tom Lendacky <thomas.lendacky@amd.com>

In preparation for other uses of the cc_platform_has() function
besides AMD's memory encryption support, selectively build the
AMD memory encryption architecture override functions only when
CONFIG_AMD_MEM_ENCRYPT=y. These functions are:

- early_memremap_pgprot_adjust()
- arch_memremap_can_ram_remap()

Additionally, routines that are only invoked by these architecture
override functions can also be conditionally built. These functions are:

- memremap_should_map_decrypted()
- memremap_is_efi_data()
- memremap_is_setup_data()
- early_memremap_is_setup_data()

And finally, phys_mem_access_encrypted() is conditionally built as well,
but requires a static inline version of it when CONFIG_AMD_MEM_ENCRYPT is
not set.

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
---
arch/x86/include/asm/io.h | 8 ++++++++
arch/x86/mm/ioremap.c | 2 +-
2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/io.h b/arch/x86/include/asm/io.h
index 841a5d104afa..5c6a4af0b911 100644
--- a/arch/x86/include/asm/io.h
+++ b/arch/x86/include/asm/io.h
@@ -391,6 +391,7 @@ extern void arch_io_free_memtype_wc(resource_size_t start, resource_size_t size)
#define arch_io_reserve_memtype_wc arch_io_reserve_memtype_wc
#endif

+#ifdef CONFIG_AMD_MEM_ENCRYPT
extern bool arch_memremap_can_ram_remap(resource_size_t offset,
unsigned long size,
unsigned long flags);
@@ -398,6 +399,13 @@ extern bool arch_memremap_can_ram_remap(resource_size_t offset,

extern bool phys_mem_access_encrypted(unsigned long phys_addr,
unsigned long size);
+#else
+static inline bool phys_mem_access_encrypted(unsigned long phys_addr,
+ unsigned long size)
+{
+ return true;
+}
+#endif

/**
* iosubmit_cmds512 - copy data to single MMIO location, in 512-bit units
diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
index 60ade7dd71bd..ccff76cedd8f 100644
--- a/arch/x86/mm/ioremap.c
+++ b/arch/x86/mm/ioremap.c
@@ -508,6 +508,7 @@ void unxlate_dev_mem_ptr(phys_addr_t phys, void *addr)
memunmap((void *)((unsigned long)addr & PAGE_MASK));
}

+#ifdef CONFIG_AMD_MEM_ENCRYPT
/*
* Examine the physical address to determine if it is an area of memory
* that should be mapped decrypted. If the memory is not part of the
@@ -746,7 +747,6 @@ bool phys_mem_access_encrypted(unsigned long phys_addr, unsigned long size)
return arch_memremap_can_ram_remap(phys_addr, size, 0);
}

-#ifdef CONFIG_AMD_MEM_ENCRYPT
/* Remap memory with encryption */
void __init *early_memremap_encrypted(resource_size_t phys_addr,
unsigned long size)
--
2.29.2