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| author | Kirill A. Shutemov <kirill@shutemov.name> | 2019-06-20 13:24:22 +0200 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2019-06-26 07:25:09 +0200 |
| commit | c1887159eb48ba40e775584cfb2a443962cf1a05 (patch) | |
| tree | 10d2d9983d82d6c9cfabe6b08cfdb28032707730 /arch/x86/kernel/head64.c | |
| parent | x86/boot/64: Fix crash if kernel image crosses page table boundary (diff) | |
| download | linux-c1887159eb48ba40e775584cfb2a443962cf1a05.tar.xz linux-c1887159eb48ba40e775584cfb2a443962cf1a05.zip | |
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
Diffstat (limited to 'arch/x86/kernel/head64.c')
| -rw-r--r-- | arch/x86/kernel/head64.c | 3 |
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; |