Commit 00c6b097 authored by Ard Biesheuvel's avatar Ard Biesheuvel Committed by Borislav Petkov (AMD)
Browse files

x86/decompressor: Assign paging related global variables earlier 



There is no need to defer the assignment of the paging related global
variables 'pgdir_shift' and 'ptrs_per_p4d' until after the trampoline is
cleaned up, so assign them as soon as it is clear that 5-level paging
will be enabled.

Signed-off-by: default avatarArd Biesheuvel <ardb@kernel.org>
Signed-off-by: default avatarBorislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230807162720.545787-9-ardb@kernel.org
parent 8b63cba7

arch/x86/boot/compressed/misc.h

+0 −2
Original line number Diff line number Diff line
@@ -179,9 +179,7 @@ static inline int count_immovable_mem_regions(void) { return 0; } 
#endif



/* ident_map_64.c */

#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: */

arch/x86/boot/compressed/pgtable_64.c

+5 −9
Original line number Diff line number Diff line
@@ -130,6 +130,11 @@ struct paging_config paging_prepare(void *rmode) 
			native_cpuid_eax(0) >= 7 &&

			(native_cpuid_ecx(7) & (1 << (X86_FEATURE_LA57 & 31)))) {

		paging_config.l5_required = 1;



		/* Initialize variables for 5-level paging */

		__pgtable_l5_enabled = 1;

		pgdir_shift = 48;

		ptrs_per_p4d = 512;

	}



	paging_config.trampoline_start = find_trampoline_placement();
@@ -206,13 +211,4 @@ void cleanup_trampoline(void *pgtable) 


	/* Restore trampoline memory */

	memcpy(trampoline_32bit, trampoline_save, TRAMPOLINE_32BIT_SIZE);



	/* Initialize variables for 5-level paging */

#ifdef CONFIG_X86_5LEVEL

	if (__read_cr4() & X86_CR4_LA57) {

		__pgtable_l5_enabled = 1;

		pgdir_shift = 48;

		ptrs_per_p4d = 512;

	}

#endif

}