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From: Jisheng Zhang <jszhang@kernel.org>
To: Guo Ren <guoren@kernel.org>
Cc: Paul Walmsley <paul.walmsley@sifive.com>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Albert Ou <aou@eecs.berkeley.edu>,
	Nathan Chancellor <nathan@kernel.org>,
	Nick Desaulniers <ndesaulniers@google.com>,
	linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
	llvm@lists.linux.dev
Subject: Re: [PATCH 3/4] riscv: fix race when vmap stack overflow and remove shadow_stack
Date: Tue, 27 Sep 2022 08:18:38 +0800	[thread overview]
Message-ID: <YzJBXsiWrbmxM6Q2@xhacker> (raw)
In-Reply-To: <CAJF2gTRFXwu5QtA8GywGaSVRPA7zeexcDHRzcngcY1zD3MFjog@mail.gmail.com>


> >  #ifdef CONFIG_VMAP_STACK
> > -static DEFINE_PER_CPU(unsigned long [OVERFLOW_STACK_SIZE/sizeof(long)],
> > -               overflow_stack)__aligned(16);
> > -/*
> > - * shadow stack, handled_ kernel_ stack_ overflow(in kernel/entry.S) is used
> > - * to get per-cpu overflow stack(get_overflow_stack).
> > - */
> > -long shadow_stack[SHADOW_OVERFLOW_STACK_SIZE/sizeof(long)];
> > -asmlinkage unsigned long get_overflow_stack(void)
> > -{
> > -       return (unsigned long)this_cpu_ptr(overflow_stack) +
> > -               OVERFLOW_STACK_SIZE;
> > -}
> > +unsigned long overflow_stack[NR_CPUS][OVERFLOW_STACK_SIZE/sizeof(long)] __aligned(16);

If NR_CPUS is large, there's a non-trival memory waste, I have a
solution for this case, will send a new version today.

Thanks

  reply	other threads:[~2022-09-27  0:28 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-09-25 17:53 [PATCH 0/4] riscv: entry: further clean up and VMAP_STACK fix Jisheng Zhang
2022-09-25 17:53 ` [PATCH 1/4] riscv: remove extra level wrappers of trace_hardirqs_{on,off} Jisheng Zhang
2022-09-25 23:18   ` Guo Ren
2022-09-25 17:53 ` [PATCH 2/4] riscv: consolidate ret_from_kernel_thread into ret_from_fork Jisheng Zhang
2022-09-25 23:25   ` Guo Ren
2022-09-26 16:05     ` Jisheng Zhang
2022-09-26 23:55       ` Guo Ren
2022-09-28 16:40         ` Jisheng Zhang
2022-09-30 11:42           ` Guo Ren
2022-09-25 17:53 ` [PATCH 3/4] riscv: fix race when vmap stack overflow and remove shadow_stack Jisheng Zhang
2022-09-25 23:46   ` Guo Ren
2022-09-27  0:18     ` Jisheng Zhang [this message]
2022-09-27  2:00       ` Guo Ren
2022-11-23 17:02   ` Deepak Gupta
2022-09-25 17:53 ` [PATCH 4/4] riscv: entry: consolidate general regs saving into save_gp Jisheng Zhang
2022-09-25 23:29   ` Guo Ren

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