Hi, On Thu, Jan 19, 2017 at 8:58 AM, Andy Gross <andy.gross@xxxxxxxxxx> wrote: > This patch adds a Qualcomm specific quirk to the arm_smccc_smc call. > > On Qualcomm ARM64 platforms, the SMC call can return before it has > completed. If this occurs, the call can be restarted, but it requires > using the returned session ID value from the interrupted SMC call. > > The quirk stores off the session ID from the interrupted call in the > quirk structure so that it can be used by the caller. > > This patch folds in a fix given by Sricharan R: > https://lkml.org/lkml/2016/9/28/272 > > Signed-off-by: Andy Gross <andy.gross@xxxxxxxxxx> > Reviewed-by: Will Deacon <will.deacon@xxxxxxx> > --- > arch/arm64/kernel/smccc-call.S | 9 ++++++++- > drivers/firmware/qcom_scm-64.c | 13 ++++++++++--- > include/linux/arm-smccc.h | 11 ++++++++--- > 3 files changed, 26 insertions(+), 7 deletions(-) > > diff --git a/arch/arm64/kernel/smccc-call.S b/arch/arm64/kernel/smccc-call.S > index 6290696..72ecdca 100644 > --- a/arch/arm64/kernel/smccc-call.S > +++ b/arch/arm64/kernel/smccc-call.S > @@ -12,6 +12,7 @@ > * > */ > #include <linux/linkage.h> > +#include <linux/arm-smccc.h> > #include <asm/asm-offsets.h> > > .macro SMCCC instr > @@ -20,7 +21,13 @@ > ldr x4, [sp] > stp x0, x1, [x4, #ARM_SMCCC_RES_X0_OFFS] > stp x2, x3, [x4, #ARM_SMCCC_RES_X2_OFFS] > - ret > + ldr x4, [sp, #8] > + cbz x4, 1f /* no quirk structure */ > + ldr x9, [x4, #ARM_SMCCC_QUIRK_ID_OFFS] > + cmp x9, #ARM_SMCCC_QUIRK_QCOM_A6 > + b.ne 1f > + str x6, [x4, ARM_SMCCC_QUIRK_STATE_OFFS] > +1: ret > .cfi_endproc > .endm This extends the SMC entry/return path quite a bit. Is this truly a qualcomm-only quirk, or are other vendors also picking it up? Why not either make arm_smccc_.* function pointers and update them accordingly, or use a custom version for the specific locations where you want/need to restart the calls? You are after all already wrapping them in qcom_scm_call(). Seems like a more appropriate change than burden all platforms with longer code path due to your quirk. -Olof -- To unsubscribe from this list: send the line "unsubscribe linux-arm-msm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
