| Message ID | 20200907181659.92449-3-seanga2@gmail.com |
|---|---|
| State | Superseded |
| Delegated to: | Andes |
| Headers | show |
| Series | riscv: Correctly handle IPIs already pending upon boot | expand |
On Tue, Sep 8, 2020 at 2:17 AM Sean Anderson <seanga2@gmail.com> wrote: > > Without a matching barrier on the write side, the barrier in handle_ipi > does nothing. It was entirely possible for the boot hart to write to addr, > arg0, and arg1 *after* sending the IPI, because there was no barrier on the > sending side. > > Fixes: 90ae28143700bae4edd23930a7772899ad259058 nits: wrong format of Fixes tag > Signed-off-by: Sean Anderson <seanga2@gmail.com> > --- > > arch/riscv/lib/smp.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/arch/riscv/lib/smp.c b/arch/riscv/lib/smp.c > index ac22136314..ab6d8bd7fa 100644 > --- a/arch/riscv/lib/smp.c > +++ b/arch/riscv/lib/smp.c > @@ -54,6 +54,8 @@ static int send_ipi_many(struct ipi_data *ipi, int wait) > gd->arch.ipi[reg].arg0 = ipi->arg0; > gd->arch.ipi[reg].arg1 = ipi->arg1; > > + __smp_mb(); > + > ret = riscv_send_ipi(reg); > if (ret) { > pr_err("Cannot send IPI to hart %d\n", reg); Reviewed-by: Bin Meng <bin.meng@windriver.com> Regards, Bin
diff --git a/arch/riscv/lib/smp.c b/arch/riscv/lib/smp.c index ac22136314..ab6d8bd7fa 100644 --- a/arch/riscv/lib/smp.c +++ b/arch/riscv/lib/smp.c @@ -54,6 +54,8 @@ static int send_ipi_many(struct ipi_data *ipi, int wait) gd->arch.ipi[reg].arg0 = ipi->arg0; gd->arch.ipi[reg].arg1 = ipi->arg1; + __smp_mb(); + ret = riscv_send_ipi(reg); if (ret) { pr_err("Cannot send IPI to hart %d\n", reg);
Without a matching barrier on the write side, the barrier in handle_ipi does nothing. It was entirely possible for the boot hart to write to addr, arg0, and arg1 *after* sending the IPI, because there was no barrier on the sending side. Fixes: 90ae28143700bae4edd23930a7772899ad259058 Signed-off-by: Sean Anderson <seanga2@gmail.com> --- arch/riscv/lib/smp.c | 2 ++ 1 file changed, 2 insertions(+)