Messages in this thread | | | Date | Thu, 09 Feb 2023 12:36:14 -0800 (PST) | Subject | Re: [PATCH V2] clocksource: riscv: Patch riscv_clock_next_event() jump before first use | From | Palmer Dabbelt <> |
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On Wed, 01 Feb 2023 11:49:42 PST (-0800), Matt Evans wrote: > A static key is used to select between SBI and Sstc timer usage in > riscv_clock_next_event(), but currently the direction is resolved > after cpuhp_setup_state() is called (which sets the next event). The > first event will therefore fall through the sbi_set_timer() path; this > breaks Sstc-only systems. So, apply the jump patching before first > use. > > Fixes: 9f7a8ff6391f ("RISC-V: Prefer sstc extension if available") > Signed-off-by: Matt Evans <mev@rivosinc.com> > --- > > V1 -> V2: Commit msg tweak. > > drivers/clocksource/timer-riscv.c | 10 +++++----- > 1 file changed, 5 insertions(+), 5 deletions(-) > > diff --git a/drivers/clocksource/timer-riscv.c b/drivers/clocksource/timer-riscv.c > index 969a552da8d2..a36d173fd6cd 100644 > --- a/drivers/clocksource/timer-riscv.c > +++ b/drivers/clocksource/timer-riscv.c > @@ -177,6 +177,11 @@ static int __init riscv_timer_init_dt(struct device_node *n) > return error; > } > > + if (riscv_isa_extension_available(NULL, SSTC)) { > + pr_info("Timer interrupt in S-mode is available via sstc extension\n"); > + static_branch_enable(&riscv_sstc_available); > + } > + > error = cpuhp_setup_state(CPUHP_AP_RISCV_TIMER_STARTING, > "clockevents/riscv/timer:starting", > riscv_timer_starting_cpu, riscv_timer_dying_cpu); > @@ -184,11 +189,6 @@ static int __init riscv_timer_init_dt(struct device_node *n) > pr_err("cpu hp setup state failed for RISCV timer [%d]\n", > error); > > - if (riscv_isa_extension_available(NULL, SSTC)) { > - pr_info("Timer interrupt in S-mode is available via sstc extension\n"); > - static_branch_enable(&riscv_sstc_available); > - } > - > return error; > } > > -- > 2.30.2
Reviewed-by: Palmer Dabbelt <palmer@rivosinc.com>
Looks like I've taken stuff here before, but I'm also happy to have the clocksource folks pick this up so
Acked-by: Palmer Dabbelt <palmer@rivosinc.com>
I don't think this is a particularly critical fix, as IIUC there's still no Sstc-only hardware in the real world. Given how late we are I'd err towards putting this on for-next anyway, so I'll give the clocksource folks a bit more time to chime in. Otherwise I'll put it on for-next before the merge window (assuming we're got an rc8 coming).
Thanks!
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