| From | Luis Henriques <> | Subject | [PATCH 3.16.y-ckt 068/126] x86/setup: Fix low identity map for >= 2GB kernel range | Date | Wed, 9 Dec 2015 09:37:18 +0000 |
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3.16.7-ckt21 -stable review patch. If anyone has any objections, please let me know.
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From: Krzysztof Mazur <krzysiek@podlesie.net>
commit 68accac392d859d24adcf1be3a90e41f978bd54c upstream.
The commit f5f3497cad8c extended the low identity mapping. However, if the kernel uses more than 2 GB (VMSPLIT_2G_OPT or VMSPLIT_1G memory split), the normal memory mapping is overwritten by the low identity mapping causing a crash. To avoid overwritting, limit the low identity map to cover only memory before kernel range (PAGE_OFFSET).
Fixes: f5f3497cad8c "x86/setup: Extend low identity map to cover whole kernel range Signed-off-by: Krzysztof Mazur <krzysiek@podlesie.net> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Laszlo Ersek <lersek@redhat.com> Cc: Matt Fleming <matt.fleming@intel.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Link: http://lkml.kernel.org/r/1446815916-22105-1-git-send-email-krzysiek@podlesie.net Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Luis Henriques <luis.henriques@canonical.com> --- arch/x86/kernel/setup.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c index 56788204d85e..b1077b8ee7af 100644 --- a/arch/x86/kernel/setup.c +++ b/arch/x86/kernel/setup.c @@ -1184,7 +1184,7 @@ void __init setup_arch(char **cmdline_p) */ clone_pgd_range(initial_page_table, swapper_pg_dir + KERNEL_PGD_BOUNDARY, - KERNEL_PGD_PTRS); + min(KERNEL_PGD_PTRS, KERNEL_PGD_BOUNDARY)); #endif tboot_probe();
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