Commit caa84136 authored by Nadav Amit's avatar Nadav Amit Committed by Ingo Molnar
Browse files

x86/mm: Initialize PGD cache during mm initialization 



Poking-mm initialization might require to duplicate the PGD in early
stage. Initialize the PGD cache earlier to prevent boot failures.

Reported-by: default avatarkernel test robot <lkp@intel.com>
Signed-off-by: default avatarNadav Amit <namit@vmware.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rick Edgecombe <rick.p.edgecombe@intel.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 4fc19708 ("x86/alternatives: Initialize temporary mm for patching")
Link: http://lkml.kernel.org/r/20190505011124.39692-1-namit@vmware.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 3950746d

arch/x86/mm/pgtable.c

+6 −4
Original line number Diff line number Diff line
@@ -373,14 +373,14 @@ static void pgd_prepopulate_user_pmd(struct mm_struct *mm, 


static struct kmem_cache *pgd_cache;



static int __init pgd_cache_init(void)

void __init pgd_cache_init(void)

{

	/*

	 * When PAE kernel is running as a Xen domain, it does not use

	 * shared kernel pmd. And this requires a whole page for pgd.

	 */

	if (!SHARED_KERNEL_PMD)

		return 0;

		return;



	/*

	 * when PAE kernel is not running as a Xen domain, it uses
@@ -390,9 +390,7 @@ static int __init pgd_cache_init(void) 
	 */

	pgd_cache = kmem_cache_create("pgd_cache", PGD_SIZE, PGD_ALIGN,

				      SLAB_PANIC, NULL);

	return 0;

}

core_initcall(pgd_cache_init);



static inline pgd_t *_pgd_alloc(void)

{
@@ -420,6 +418,10 @@ static inline void _pgd_free(pgd_t *pgd) 
}

#else



void __init pgd_cache_init(void)

{

}



static inline pgd_t *_pgd_alloc(void)

{

	return (pgd_t *)__get_free_pages(PGALLOC_GFP, PGD_ALLOCATION_ORDER);

include/asm-generic/pgtable.h

+2 −0
Original line number Diff line number Diff line
@@ -1126,6 +1126,8 @@ int phys_mem_access_prot_allowed(struct file *file, unsigned long pfn, 
static inline void init_espfix_bsp(void) { }

#endif



extern void __init pgd_cache_init(void);



#ifndef __HAVE_ARCH_PFN_MODIFY_ALLOWED

static inline bool pfn_modify_allowed(unsigned long pfn, pgprot_t prot)

{

init/main.c

+3 −0
Original line number Diff line number Diff line
@@ -506,6 +506,8 @@ void __init __weak mem_encrypt_init(void) { } 


void __init __weak poking_init(void) { }



void __init __weak pgd_cache_init(void) { }



bool initcall_debug;

core_param(initcall_debug, initcall_debug, bool, 0644);
@@ -537,6 +539,7 @@ static void __init mm_init(void) 
	init_espfix_bsp();

	/* Should be run after espfix64 is set up. */

	pti_init();

	pgd_cache_init();

}



void __init __weak arch_call_rest_init(void)

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