cr: generalized the prototype of the routine restore_fpu()

A struct sigframe* instead of fpu_state_t should be passed
to the routine restore_fpu() since FPU registers are stored
in different fields of the sigframe in different architectures.
An architecture-specific implementation of the routine restore_fpu()
should know details of this layout instead of construct_sigframe().

This change makes it possible to move ARM FPU restoration
from sigreturn_prep_fpu_frame() (where it caused a segfault
since the pointer fpu_stat has become invalid in the dumper
address space) to restore_fpu()
Signed-off-by: Alexander Kartashov <alekskartashov@parallels.com>
Acked-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

arch/arm/crtools.c

@@ -197,10 +197,12 @@ void arch_free_thread_info(CoreEntry *core)
 	}
 }
 
-int restore_fpu(fpu_state_t *fpu_state, CoreEntry *core)
+int restore_fpu(struct rt_sigframe *sigframe, CoreEntry *core)
 {
-	memcpy(fpu_state->ufp.fpregs, CORE_THREAD_ARCH_INFO(core)->fpstate->vfp_regs,
-		sizeof(fpu_state->ufp.fpregs));
+	struct aux_sigframe *aux = (struct aux_sigframe *)&sigframe->sig.uc.uc_regspace;
+	fpu_state_t *fpu_state = &sigframe->fpu_state;
+
+	memcpy(&aux->vfp.ufp, CORE_THREAD_ARCH_INFO(core)->fpstate->vfp_regs, sizeof(aux->vfp.ufp));
 	fpu_state->ufp.fpscr = CORE_THREAD_ARCH_INFO(core)->fpstate->fpscr;
 
 	return 0;
@@ -259,7 +261,6 @@ int sigreturn_prep_fpu_frame(struct rt_sigframe *sigframe, fpu_state_t *fpu_stat
 
 	aux->vfp.magic = VFP_MAGIC;
 	aux->vfp.size = VFP_STORAGE_SIZE;
-	builtin_memcpy(&aux->vfp.ufp, &fpu_state->ufp, sizeof(aux->vfp.ufp));
 
 	return 0;
 }

arch/arm/include/asm/restore.h

@@ -20,6 +20,6 @@ static inline void core_get_tls(CoreEntry *pcore, u32 *ptls)
 }
 
 
-int restore_fpu(fpu_state_t *fpu_state, CoreEntry *core);
+int restore_fpu(struct rt_sigframe *sigframe, CoreEntry *core);
 
 #endif

arch/x86/crtools.c

@@ -373,8 +373,9 @@ static void show_rt_xsave_frame(struct xsave_struct *x)
 	pr_debug("-----------------------\n");
 }
 
-int restore_fpu(fpu_state_t *fpu_state, CoreEntry *core)
+int restore_fpu(struct rt_sigframe *sigframe, CoreEntry *core)
 {
+	fpu_state_t *fpu_state = &sigframe->fpu_state;
 	struct xsave_struct *x = &fpu_state->xsave;
 
 	/*

arch/x86/include/asm/restore.h

@@ -18,6 +18,6 @@
 #define core_get_tls(pcore, ptls)
 
 
-int restore_fpu(fpu_state_t *fpu_state, CoreEntry *core);
+int restore_fpu(struct rt_sigframe *sigframe, CoreEntry *core);
 
 #endif

sigframe.c

@@ -21,7 +21,7 @@ int construct_sigframe(struct rt_sigframe *sigframe,
 		memset(blk_sigset, 0, sizeof(k_rtsigset_t));
 
 	sigframe->fpu_state.has_fpu = true;
-	if (restore_fpu(&sigframe->fpu_state, core))
+	if (restore_fpu(sigframe, core))
 		return -1;
 
 	if (sigframe->fpu_state.has_fpu)