Commit a9ee679b authored by Michael Roth's avatar Michael Roth Committed by Borislav Petkov
Browse files

x86/compressed: Export and rename add_identity_map() 



SEV-specific code will need to add some additional mappings, but doing
this within ident_map_64.c requires some SEV-specific helpers to be
exported and some SEV-specific struct definitions to be pulled into
ident_map_64.c. Instead, export add_identity_map() so SEV-specific (and
other subsystem-specific) code can be better contained outside of
ident_map_64.c.

While at it, rename the function to kernel_add_identity_map(), similar
to the kernel_ident_mapping_init() function it relies upon.

No functional changes.

Suggested-by: default avatarBorislav Petkov <bp@alien8.de>
Signed-off-by: default avatarMichael Roth <michael.roth@amd.com>
Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20220307213356.2797205-37-brijesh.singh@amd.com
parent 5f211f4f

arch/x86/boot/compressed/ident_map_64.c

+9 −9
Original line number Diff line number Diff line
@@ -90,7 +90,7 @@ static struct x86_mapping_info mapping_info; 
/*

 * Adds the specified range to the identity mappings.

 */

static void add_identity_map(unsigned long start, unsigned long end)

void kernel_add_identity_map(unsigned long start, unsigned long end)

{

	int ret;
@@ -157,11 +157,11 @@ void initialize_identity_maps(void *rmode) 
	 * explicitly here in case the compressed kernel does not touch them,

	 * or does not touch all the pages covering them.

	 */

	add_identity_map((unsigned long)_head, (unsigned long)_end);

	kernel_add_identity_map((unsigned long)_head, (unsigned long)_end);

	boot_params = rmode;

	add_identity_map((unsigned long)boot_params, (unsigned long)(boot_params + 1));

	kernel_add_identity_map((unsigned long)boot_params, (unsigned long)(boot_params + 1));

	cmdline = get_cmd_line_ptr();

	add_identity_map(cmdline, cmdline + COMMAND_LINE_SIZE);

	kernel_add_identity_map(cmdline, cmdline + COMMAND_LINE_SIZE);



	/* Load the new page-table. */

	sev_verify_cbit(top_level_pgt);
@@ -246,10 +246,10 @@ static int set_clr_page_flags(struct x86_mapping_info *info, 
	 * It should already exist, but keep things generic.

	 *

	 * To map the page just read from it and fault it in if there is no

	 * mapping yet. add_identity_map() can't be called here because that

	 * would unconditionally map the address on PMD level, destroying any

	 * PTE-level mappings that might already exist. Use assembly here so

	 * the access won't be optimized away.

	 * mapping yet. kernel_add_identity_map() can't be called here because

	 * that would unconditionally map the address on PMD level, destroying

	 * any PTE-level mappings that might already exist. Use assembly here

	 * so the access won't be optimized away.

	 */

	asm volatile("mov %[address], %%r9"

		     :: [address] "g" (*(unsigned long *)address)
@@ -363,5 +363,5 @@ void do_boot_page_fault(struct pt_regs *regs, unsigned long error_code) 
	 * Error code is sane - now identity map the 2M region around

	 * the faulting address.

	 */

	add_identity_map(address, end);

	kernel_add_identity_map(address, end);

}

arch/x86/boot/compressed/misc.h

+1 −0
Original line number Diff line number Diff line
@@ -156,6 +156,7 @@ static inline int count_immovable_mem_regions(void) { return 0; } 
#ifdef CONFIG_X86_5LEVEL

extern unsigned int __pgtable_l5_enabled, pgdir_shift, ptrs_per_p4d;

#endif

extern void kernel_add_identity_map(unsigned long start, unsigned long end);



/* Used by PAGE_KERN* macros: */

extern pteval_t __default_kernel_pte_mask;