[PATCH v2 1/6] x86_64, init: clear init_level4_pgt earlier
From: Andrey Ryabinin <hidden>
Date: 2015-07-02 09:10:32
Also in:
lkml
Subsystem:
the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
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 <redacted> Cc: <redacted> # 4.0+ --- arch/x86/kernel/head64.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index 5a46681..65c8985 100644
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c@@ -166,6 +166,8 @@ asmlinkage __visible void __init x86_64_start_kernel(char * real_mode_data) /* 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_start_kernel(char * real_mode_data) */ 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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2.4.5