x86/fpu: Use fpstate::size

Make use of fpstate::size in various places which require the buffer size
information for sanity checks or memcpy() sizing.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20211013145322.973518954@linutronix.de

diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c
index a8cc20e..cb48c80 100644 (file)
--- a/arch/x86/kernel/fpu/core.c
+++ b/arch/x86/kernel/fpu/core.c
@@ -166,13 +166,12 @@ void fpu_swap_kvm_fpu(struct fpu *save, struct fpu *rstor, u64 restore_mask)
        fpregs_lock();
 
        if (save) {
-               if (test_thread_flag(TIF_NEED_FPU_LOAD)) {
-                       memcpy(&save->fpstate->regs,
-                              &current->thread.fpu.fpstate->regs,
-                              fpu_kernel_xstate_size);
-               } else {
+               struct fpstate *fpcur = current->thread.fpu.fpstate;
+
+               if (test_thread_flag(TIF_NEED_FPU_LOAD))
+                       memcpy(&save->fpstate->regs, &fpcur->regs, fpcur->size);
+               else
                        save_fpregs_to_fpstate(save);
-               }
        }
 
        if (rstor) {
@@ -398,7 +397,7 @@ int fpu_clone(struct task_struct *dst)
        fpregs_lock();
        if (test_thread_flag(TIF_NEED_FPU_LOAD)) {
                memcpy(&dst_fpu->fpstate->regs, &src_fpu->fpstate->regs,
-                      fpu_kernel_xstate_size);
+                      dst_fpu->fpstate->size);
        } else {
                save_fpregs_to_fpstate(dst_fpu);
        }

diff --git a/arch/x86/kernel/fpu/signal.c b/arch/x86/kernel/fpu/signal.c
index c54c2a3..aa93291 100644 (file)
--- a/arch/x86/kernel/fpu/signal.c
+++ b/arch/x86/kernel/fpu/signal.c
@@ -313,15 +313,13 @@ retry:
 static bool __fpu_restore_sig(void __user *buf, void __user *buf_fx,
                              bool ia32_fxstate)
 {
-       int state_size = fpu_kernel_xstate_size;
        struct task_struct *tsk = current;
        struct fpu *fpu = &tsk->thread.fpu;
        struct user_i387_ia32_struct env;
+       bool success, fx_only = false;
        union fpregs_state *fpregs;
+       unsigned int state_size;
        u64 user_xfeatures = 0;
-       bool fx_only = false;
-       bool success;
-
 
        if (use_xsave()) {
                struct _fpx_sw_bytes fx_sw_user;
@@ -334,6 +332,7 @@ static bool __fpu_restore_sig(void __user *buf, void __user *buf_fx,
                user_xfeatures = fx_sw_user.xfeatures;
        } else {
                user_xfeatures = XFEATURE_MASK_FPSSE;
+               state_size = fpu->fpstate->size;
        }
 
        if (likely(!ia32_fxstate)) {