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x86/process: Move arch_thread_struct_whitelist() out of line

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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
This commit is contained in:
Thomas Gleixner 2021-10-13 16:55:45 +02:00 • committed by Borislav Petkov
parent f0cbc8b3cd
commit 2dd8eedc80
3 changed files with 15 additions and 6 deletions
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9
arch/x86/include/asm/processor.h
View file

@ -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

10
arch/x86/kernel/fpu/core.c
View file

@ -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

2
arch/x86/kernel/fpu/internal.h
View file

@ -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 */