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x86/power/64: Fix page-table setup for temporary text mapping

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On a system with 4-level page-tables there is no p4d, so the pud in the pgd
should be mapped. The old code before commit fb43d6cb91 already did that.

The change from above commit causes an invalid page-table which causes
undefined behavior. In one report it caused triple faults.

Fix it by changing the p4d back to pud.

Fixes: fb43d6cb91 ('x86/mm: Do not auto-massage page protections')
Reported-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Michal Kubecek <mkubecek@suse.cz>
Tested-by: Borislav Petkov <bp@suse.de>
Cc: linux-pm@vger.kernel.org
Cc: rjw@rjwysocki.net
Cc: pavel@ucw.cz
Cc: hpa@zytor.com
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lkml.kernel.org/r/1524162360-26179-1-git-send-email-joro@8bytes.org
This commit is contained in:
Joerg Roedel 2018-04-19 20:26:00 +02:00 committed by Thomas Gleixner
parent d6ef1f194b
commit 05189820da
1 changed files with 1 additions and 1 deletions
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2
arch/x86/power/hibernate_64.c
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@ -98,7 +98,7 @@ static int set_up_temporary_text_mapping(pgd_t *pgd)
set_pgd(pgd + pgd_index(restore_jump_address), new_pgd);
} else {
/* No p4d for 4-level paging: point the pgd to the pud page table */
pgd_t new_pgd = __pgd(__pa(p4d) | pgprot_val(pgtable_prot));
pgd_t new_pgd = __pgd(__pa(pud) | pgprot_val(pgtable_prot));
set_pgd(pgd + pgd_index(restore_jump_address), new_pgd);
}