Re: [PATCH] arm64: setup return path for el1_undef
On Tue, Dec 23, 2014 at 11:57 PM, Catalin Marinas wrote: > On Tue, Dec 23, 2014 at 03:15:10PM +, 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. Thanks for your reply. It was just a code inspection. Min-Hua > >> 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 >> --- >> 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 >> movx0, sp >> -bdo_undefinstr >> +bldo_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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] arm64: setup return path for el1_undef
On Tue, Dec 23, 2014 at 03:15:10PM +, 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 > --- > 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 > movx0, sp > -bdo_undefinstr > +bldo_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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
[PATCH] arm64: setup return path for el1_undef
Setup return path for el1_undef since el1_undef may be handled by handlers. 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 --- 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 movx0, sp -bdo_undefinstr +bldo_undefinstr +kernel_exit 1 el1_dbg: /* * Debug exception handling -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
[PATCH] arm64: setup return path for el1_undef
Setup return path for el1_undef since el1_undef may be handled by handlers. 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.c...@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 movx0, sp -bdo_undefinstr +bldo_undefinstr +kernel_exit 1 el1_dbg: /* * Debug exception handling -- 1.7.10.4 -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] arm64: setup return path for el1_undef
On Tue, Dec 23, 2014 at 03:15:10PM +, 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.c...@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 movx0, sp -bdo_undefinstr +bldo_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 -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] arm64: setup return path for el1_undef
On Tue, Dec 23, 2014 at 11:57 PM, Catalin Marinas catalin.mari...@arm.com wrote: On Tue, Dec 23, 2014 at 03:15:10PM +, 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. Thanks for your reply. It was just a code inspection. Min-Hua 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.c...@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 movx0, sp -bdo_undefinstr +bldo_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 -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/