Commit 2dd8eedc authored by Thomas Gleixner's avatar Thomas Gleixner Committed by Borislav Petkov
Browse files

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: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20211013145322.869001791@linutronix.de
parent f0cbc8b3

arch/x86/include/asm/processor.h

+3 −6
Original line number Diff line number Diff line
@@ -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

arch/x86/kernel/fpu/core.c

+10 −0
Original line number Diff line number Diff line
@@ -404,6 +404,16 @@ int fpu_clone(struct task_struct *dst) 
	return 0;

}



/*

 * 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

arch/x86/kernel/fpu/internal.h

+2 −0
Original line number Diff line number Diff line
@@ -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 */