On Thu, Jul 12, 2018 at 03:43:10PM -0700, Kees Cook wrote: > On Tue, Apr 17, 2018 at 1:11 AM, Thierry Reding <[email protected]> wrote: > > On Mon, Apr 16, 2018 at 08:21:09PM +0200, Stefan Agner wrote: > >> On 16.04.2018 18:08, Stephen Warren wrote: > >> > On 04/16/2018 09:56 AM, Stefan Agner wrote: > >> >> On 27.03.2018 14:16, Dmitry Osipenko wrote: > >> >>> On 27.03.2018 14:54, Robin Murphy wrote: > >> >>>> On 26/03/18 22:20, Dmitry Osipenko wrote: > >> >>>>> On 25.03.2018 21:09, Stefan Agner wrote: > >> >>>>>> As documented in GCC naked functions should only use Basic asm > >> >>>>>> syntax. The Extended asm or mixture of Basic asm and "C" code is > >> >>>>>> not guaranteed. Currently this works because it was hard coded > >> >>>>>> to follow and check GCC behavior for arguments and register > >> >>>>>> placement. > >> >>>>>> > >> >>>>>> Furthermore with clang using parameters in Extended asm in a > >> >>>>>> naked function is not supported: > >> >>>>>> arch/arm/firmware/trusted_foundations.c:47:10: error: parameter > >> >>>>>> references not allowed in naked functions > >> >>>>>> : "r" (type), "r" (arg1), "r" (arg2) > >> >>>>>> ^ > >> >>>>>> > >> >>>>>> Use a regular function to be more portable. This aligns also with > >> >>>>>> the other smc call implementations e.g. in qcom_scm-32.c and > >> >>>>>> bcm_kona_smc.c. > >> >>>>>> > >> >>>>>> Cc: Dmitry Osipenko <[email protected]> > >> >>>>>> Cc: Stephen Warren <[email protected]> > >> >>>>>> Cc: Thierry Reding <[email protected]> > >> >>>>>> Signed-off-by: Stefan Agner <[email protected]> > >> >>>>>> --- > >> >>>>>> Changes in v2: > >> >>>>>> - Keep stmfd/ldmfd to avoid potential ABI issues > >> >>>>>> > >> >>>>>> arch/arm/firmware/trusted_foundations.c | 14 +++++++++----- > >> >>>>>> 1 file changed, 9 insertions(+), 5 deletions(-) > >> >>>>>> > >> >>>>>> diff --git a/arch/arm/firmware/trusted_foundations.c > >> >>>>>> b/arch/arm/firmware/trusted_foundations.c > >> >>>>>> index 3fb1b5a1dce9..689e6565abfc 100644 > >> >>>>>> --- a/arch/arm/firmware/trusted_foundations.c > >> >>>>>> +++ b/arch/arm/firmware/trusted_foundations.c > >> >>>>>> @@ -31,21 +31,25 @@ > >> >>>>>> static unsigned long cpu_boot_addr; > >> >>>>>> -static void __naked tf_generic_smc(u32 type, u32 arg1, u32 arg2) > >> >>>>>> +static void tf_generic_smc(u32 type, u32 arg1, u32 arg2) > >> >>>>>> { > >> >>>>>> + register u32 r0 asm("r0") = type; > >> >>>>>> + register u32 r1 asm("r1") = arg1; > >> >>>>>> + register u32 r2 asm("r2") = arg2; > >> >>>>>> + > >> >>>>>> asm volatile( > >> >>>>>> ".arch_extension sec\n\t" > >> >>>>>> - "stmfd sp!, {r4 - r11, lr}\n\t" > >> >>>>>> + "stmfd sp!, {r4 - r11}\n\t" > >> >>>>>> __asmeq("%0", "r0") > >> >>>>>> __asmeq("%1", "r1") > >> >>>>>> __asmeq("%2", "r2") > >> >>>>>> "mov r3, #0\n\t" > >> >>>>>> "mov r4, #0\n\t" > >> >>>>>> "smc #0\n\t" > >> >>>>>> - "ldmfd sp!, {r4 - r11, pc}" > >> >>>>>> + "ldmfd sp!, {r4 - r11}\n\t" > >> >>>>>> : > >> >>>>>> - : "r" (type), "r" (arg1), "r" (arg2) > >> >>>>>> - : "memory"); > >> >>>>>> + : "r" (r0), "r" (r1), "r" (r2) > >> >>>>>> + : "memory", "r3", "r12", "lr"); > >> >>>>> > >> >>>>> Although seems "lr" won't be affected by SMC invocation because it > >> >>>>> should be > >> >>>>> banked and hence could be omitted entirely from the code. Maybe > >> >>>>> somebody could > >> >>>>> confirm this. > >> >>>> Strictly per the letter of the architecture, the SMC could be trapped > >> >>>> to Hyp > >> >>>> mode, and a hypervisor might clobber LR_usr in the process of > >> >>>> forwarding the > >> >>>> call to the firmware secure monitor (since Hyp doesn't have a banked > >> >>>> LR of its > >> >>>> own). Admittedly there are probably no real systems with the > >> >>>> appropriate > >> >>>> hardware/software combination to hit that, but on the other hand if > >> >>>> this gets > >> >>>> inlined where the compiler has already created a stack frame then an > >> >>>> LR clobber > >> >>>> is essentially free, so I reckon we're better off keeping it for > >> >>>> reassurance. > >> >>>> This isn't exactly a critical fast path anyway. > >> >>> > >> >>> Okay, thank you for the clarification. > >> >> > >> >> So it seems this change is fine? > >> >> > >> >> Stephen, you picked up changes for this driver before, is this patch > >> >> going through your tree? > >> > > >> > You had best ask Thierry; he's taken over Tegra maintenance upstream. > >> > But that said, don't files in arch/arm go through Russell? > >> > >> I think the last patches applied to that file went through your tree. > >> > >> Thierry, Russel, any preferences? > > > > I don't mind picking this up into the Tegra tree. Might be a good idea > > to move this into drivers/firmware, though, since that's where all the > > other firmware-related drivers reside. > > > > Firmware code, such as the BPMP driver, usually goes through ARM-SoC > > these days. I think this is in the same category. > > > > Russell, any objections to me picking this patch up and moving it into > > drivers/firmware? > > Please take this -- without it I'm seeing build failures on the arm > allmodconfig under gcc 7.3.0:
Sorry, I'd completely missed this... now replied on the original patch. -- RMK's Patch system: http://www.armlinux.org.uk/developer/patches/ FTTC broadband for 0.8mile line in suburbia: sync at 13.8Mbps down 630kbps up According to speedtest.net: 13Mbps down 490kbps up
