From c1887159eb48ba40e775584cfb2a443962cf1a05 Mon Sep 17 00:00:00 2001 From: "Kirill A. Shutemov" Date: Thu, 20 Jun 2019 14:24:22 +0300 Subject: x86/boot/64: Add missing fixup_pointer() for next_early_pgt access __startup_64() uses fixup_pointer() to access global variables in a position-independent fashion. Access to next_early_pgt was wrapped into the helper, but one instance in the 5-level paging branch was missed. GCC generates a R_X86_64_PC32 PC-relative relocation for the access which doesn't trigger the issue, but Clang emmits a R_X86_64_32S which leads to an invalid memory access and system reboot. Fixes: 187e91fe5e91 ("x86/boot/64/clang: Use fixup_pointer() to access 'next_early_pgt'") Signed-off-by: Kirill A. Shutemov Signed-off-by: Thomas Gleixner Cc: Borislav Petkov Cc: "H. Peter Anvin" Cc: Dave Hansen Cc: Andy Lutomirski Cc: Peter Zijlstra Cc: Alexander Potapenko Link: https://lkml.kernel.org/r/20190620112422.29264-1-kirill.shutemov@linux.intel.com --- arch/x86/kernel/head64.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'arch') diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c index 7df5bce4e1be..29ffa495bd1c 100644 --- a/arch/x86/kernel/head64.c +++ b/arch/x86/kernel/head64.c @@ -184,7 +184,8 @@ unsigned long __head __startup_64(unsigned long physaddr, pgtable_flags = _KERNPG_TABLE_NOENC + sme_get_me_mask(); if (la57) { - p4d = fixup_pointer(early_dynamic_pgts[next_early_pgt++], physaddr); + p4d = fixup_pointer(early_dynamic_pgts[(*next_pgt_ptr)++], + physaddr); i = (physaddr >> PGDIR_SHIFT) % PTRS_PER_PGD; pgd[i + 0] = (pgdval_t)p4d + pgtable_flags; -- cgit