x86/process: Move arch_thread_struct_whitelist() out of line

In preparation for dynamically enabled FPU features move the function
out of line as the goal is to expose less and not more information.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20211013145322.869001791@linutronix.de

diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 4519d33..1bd3e8d 100644 (file)
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -461,9 +461,6 @@ DECLARE_PER_CPU(struct irq_stack *, hardirq_stack_ptr);
 DECLARE_PER_CPU(struct irq_stack *, softirq_stack_ptr);
 #endif /* !X86_64 */
 
-extern unsigned int fpu_kernel_xstate_size;
-extern unsigned int fpu_user_xstate_size;
-
 struct perf_event;
 
 struct thread_struct {
@@ -537,12 +534,12 @@ struct thread_struct {
         */
 };
 
-/* Whitelist the FPU register state from the task_struct for hardened usercopy. */
+extern void fpu_thread_struct_whitelist(unsigned long *offset, unsigned long *size);
+
 static inline void arch_thread_struct_whitelist(unsigned long *offset,
                                                unsigned long *size)
 {
-       *offset = offsetof(struct thread_struct, fpu.__fpstate.regs);
-       *size = fpu_kernel_xstate_size;
+       fpu_thread_struct_whitelist(offset, size);
 }
 
 static inline void

diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c
index 14560fd..c6df975 100644 (file)
--- a/arch/x86/kernel/fpu/core.c
+++ b/arch/x86/kernel/fpu/core.c
@@ -405,6 +405,16 @@ int fpu_clone(struct task_struct *dst)
 }
 
 /*
+ * Whitelist the FPU register state embedded into task_struct for hardened
+ * usercopy.
+ */
+void fpu_thread_struct_whitelist(unsigned long *offset, unsigned long *size)
+{
+       *offset = offsetof(struct thread_struct, fpu.__fpstate.regs);
+       *size = fpu_kernel_xstate_size;
+}
+
+/*
  * Drops current FPU state: deactivates the fpregs and
  * the fpstate. NOTE: it still leaves previous contents
  * in the fpregs in the eager-FPU case.

diff --git a/arch/x86/kernel/fpu/internal.h b/arch/x86/kernel/fpu/internal.h
index e1d8a35..5c4f71f 100644 (file)
--- a/arch/x86/kernel/fpu/internal.h
+++ b/arch/x86/kernel/fpu/internal.h
@@ -2,6 +2,8 @@
 #ifndef __X86_KERNEL_FPU_INTERNAL_H
 #define __X86_KERNEL_FPU_INTERNAL_H
 
+extern unsigned int fpu_kernel_xstate_size;
+extern unsigned int fpu_user_xstate_size;
 extern struct fpstate init_fpstate;
 
 /* CPU feature check wrappers */