x86/insn-eval: Add support for 64-bit kernel mode
To support evaluating 64-bit kernel mode instructions:
* Replace existing checks for user_64bit_mode() with a new helper that
checks whether code is being executed in either 64-bit kernel mode or
64-bit user mode.
* Select the GS base depending on whether the instruction is being
evaluated in kernel mode.
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: kasan-dev@googlegroups.com
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: x86-ml <x86@kernel.org>
Link: https://lkml.kernel.org/r/20191218231150.12139-1-jannh@google.com
diff --git a/arch/x86/include/asm/ptrace.h b/arch/x86/include/asm/ptrace.h
index 5057a8e..ac45b06 100644
--- a/arch/x86/include/asm/ptrace.h
+++ b/arch/x86/include/asm/ptrace.h
@@ -159,6 +159,19 @@ static inline bool user_64bit_mode(struct pt_regs *regs)
#endif
}
+/*
+ * Determine whether the register set came from any context that is running in
+ * 64-bit mode.
+ */
+static inline bool any_64bit_mode(struct pt_regs *regs)
+{
+#ifdef CONFIG_X86_64
+ return !user_mode(regs) || user_64bit_mode(regs);
+#else
+ return false;
+#endif
+}
+
#ifdef CONFIG_X86_64
#define current_user_stack_pointer() current_pt_regs()->sp
#define compat_user_stack_pointer() current_pt_regs()->sp