Messages in this thread Patch in this message | | | Date | Tue, 23 Dec 2014 15:57:14 +0000 | From | Catalin Marinas <> | Subject | Re: [PATCH] arm64: setup return path for el1_undef |
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On Tue, Dec 23, 2014 at 03:15:10PM +0000, Min-Hua Chen wrote: > Setup return path for el1_undef since el1_undef may > be handled by handlers.
Did you find a real issue or it was just code inspection.
> asmlinkage void __exception do_undefinstr(struct pt_regs *regs) > { > siginfo_t info; > void __user *pc = (void __user *)instruction_pointer(regs); > > /* check for AArch32 breakpoint instructions */ > if (!aarch32_break_handler(regs)) > return; > > if (call_undef_hook(regs) == 0) > return; > > ... > } > Signed-off-by: Min-Hua Chen <orca.chen@gmail.com> > --- > arch/arm64/kernel/entry.S | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S > index fd4fa37..86ebec5 100644 > --- a/arch/arm64/kernel/entry.S > +++ b/arch/arm64/kernel/entry.S > @@ -313,7 +313,8 @@ el1_undef: > */ > enable_dbg > mov x0, sp > - b do_undefinstr > + bl do_undefinstr > + kernel_exit 1 > el1_dbg: > /* > * Debug exception handling
I don't think this is needed. The code is pretty convoluted but for an EL1 undefined exception we should never return from do_undefinstr(). The call_undef_hook() function returns 1 if !user_mode(regs) and this should cause a kernel panic. Basically we do not allow any kind of undefined instructions in the arm64 kernel.
-- Catalin
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