LoongArch: Save LBT before FPU in setup_sigcontext()

[ Upstream commit 112ca94f6c3b3e0b2002a240de43c487a33e0234 ]

Now if preemption happens between protected_save_fpu_context() and
protected_save_lbt_context(), FTOP context is lost. Because FTOP is
saved by protected_save_lbt_context() but protected_save_fpu_context()
disables TM before that. So save LBT before FPU in setup_sigcontext()
to avoid this potential risk.

Signed-off-by: Hanlu Li <lihanlu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/arch/loongarch/kernel/signal.c b/arch/loongarch/kernel/signal.c
index 4740cb5b238898aef497c74d8d0ae49065df60af..c9f7ca778364ed61e6ac03b130038905c8d9714b 100644 (file)
--- a/arch/loongarch/kernel/signal.c
+++ b/arch/loongarch/kernel/signal.c
@@ -677,6 +677,11 @@ static int setup_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc,
        for (i = 1; i < 32; i++)
                err |= __put_user(regs->regs[i], &sc->sc_regs[i]);
 
+#ifdef CONFIG_CPU_HAS_LBT
+       if (extctx->lbt.addr)
+               err |= protected_save_lbt_context(extctx);
+#endif
+
        if (extctx->lasx.addr)
                err |= protected_save_lasx_context(extctx);
        else if (extctx->lsx.addr)
@@ -684,11 +689,6 @@ static int setup_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc,
        else if (extctx->fpu.addr)
                err |= protected_save_fpu_context(extctx);
 
-#ifdef CONFIG_CPU_HAS_LBT
-       if (extctx->lbt.addr)
-               err |= protected_save_lbt_context(extctx);
-#endif
-
        /* Set the "end" magic */
        info = (struct sctx_info *)extctx->end.addr;
        err |= __put_user(0, &info->magic);