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authorKirill A. Shutemov <kirill@shutemov.name>2019-06-20 14:24:22 +0300
committerThomas Gleixner <tglx@linutronix.de>2019-06-26 07:25:09 +0200
commitc1887159eb48ba40e775584cfb2a443962cf1a05 (patch)
tree10d2d9983d82d6c9cfabe6b08cfdb28032707730
parent81c7ed296dcd02bc0b4488246d040e03e633737a (diff)
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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 <kirill.shutemov@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Borislav Petkov <bp@alien8.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Alexander Potapenko <glider@google.com> Link: https://lkml.kernel.org/r/20190620112422.29264-1-kirill.shutemov@linux.intel.com
-rw-r--r--arch/x86/kernel/head64.c3
1 files changed, 2 insertions, 1 deletions
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;