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LoongArch: Save LBT before FPU in setup_sigcontext()

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[ Upstream commit 112ca94f6c ]

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>
This commit is contained in:
Huacai Chen 2025-08-20 22:23:44 +08:00 committed by Greg Kroah-Hartman
parent dc4a024b19
commit ee58a0a353
1 changed files with 5 additions and 5 deletions
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10
arch/loongarch/kernel/signal.c
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@ -697,6 +697,11 @@ 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)
@ -704,11 +709,6 @@ 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);