Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 4.1 022/123] x86/init: Clear init_level4_pgt earlier | Date | Sat, 8 Aug 2015 15:08:20 -0700 |
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4.1-stable review patch. If anyone has any objections, please let me know.
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From: Andrey Ryabinin <a.ryabinin@samsung.com>
commit d0f77d4d04b222a817925d33ba3589b190bfa863 upstream.
Currently x86_64_start_kernel() has two KASAN related function calls. The first call maps shadow to early_level4_pgt, the second maps shadow to init_level4_pgt.
If we move clear_page(init_level4_pgt) earlier, we could hide KASAN low level detail from generic x86_64 initialization code. The next patch will do it.
Signed-off-by: Andrey Ryabinin <a.ryabinin@samsung.com> Cc: Alexander Popov <alpopov@ptsecurity.com> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Konovalov <adech.fo@gmail.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1435828178-10975-2-git-send-email-a.ryabinin@samsung.com Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- arch/x86/kernel/head64.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- a/arch/x86/kernel/head64.c +++ b/arch/x86/kernel/head64.c @@ -166,6 +166,8 @@ asmlinkage __visible void __init x86_64_ /* clear bss before set_intr_gate with early_idt_handler */ clear_bss(); + clear_page(init_level4_pgt); + for (i = 0; i < NUM_EXCEPTION_VECTORS; i++) set_intr_gate(i, early_idt_handler_array[i]); load_idt((const struct desc_ptr *)&idt_descr); @@ -177,7 +179,6 @@ asmlinkage __visible void __init x86_64_ */ load_ucode_bsp(); - clear_page(init_level4_pgt); /* set init_level4_pgt kernel high mapping*/ init_level4_pgt[511] = early_level4_pgt[511];
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