| Message ID | 20220209123800.269774-2-heiko@sntech.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | riscv: support for Svpbmt and D1 memory types | expand |
On Wed, Feb 9, 2022 at 4:38 AM Heiko Stuebner <heiko@sntech.de> wrote: > > The callback used inside sbi_remote_fence_i is set at sbi probe time > to the needed variant. Before that it is a NULL pointer. > > Some users like the flush_icache_*() functions suggest a generic > functionality, that doesn't depend on a specific boot-stage but > uses sbi_remote_fence_i as one option to flush other cpu cores. > > So they definitly shouldn't run into null-pointer dereference /s/definitly/definitely > issues when called "too early" during boot. > > So introduce an empty function to be the standard for the __sbi_rfence > function pointer until sbi_init has run. > > Users of sbi_remote_fence_i will have separate code for the local > cpu and sbi_init() is called before other cpus are brought up. > So there are no other cpus present at the time when the issue > might happen. > > Signed-off-by: Heiko Stuebner <heiko@sntech.de> > --- > arch/riscv/kernel/sbi.c | 10 +++++++++- > 1 file changed, 9 insertions(+), 1 deletion(-) > > diff --git a/arch/riscv/kernel/sbi.c b/arch/riscv/kernel/sbi.c > index f72527fcb347..c839acd668d3 100644 > --- a/arch/riscv/kernel/sbi.c > +++ b/arch/riscv/kernel/sbi.c > @@ -15,11 +15,19 @@ > unsigned long sbi_spec_version __ro_after_init = SBI_SPEC_VERSION_DEFAULT; > EXPORT_SYMBOL(sbi_spec_version); > > +static int __sbi_rfence_none(int fid, const struct cpumask *cpu_mask, > + unsigned long start, unsigned long size, > + unsigned long arg4, unsigned long arg5) > +{ > + return -EOPNOTSUPP; > +} > + > static void (*__sbi_set_timer)(uint64_t stime) __ro_after_init; > static int (*__sbi_send_ipi)(const struct cpumask *cpu_mask) __ro_after_init; > static int (*__sbi_rfence)(int fid, const struct cpumask *cpu_mask, > unsigned long start, unsigned long size, > - unsigned long arg4, unsigned long arg5) __ro_after_init; > + unsigned long arg4, unsigned long arg5) > + __ro_after_init = __sbi_rfence_none; > > struct sbiret sbi_ecall(int ext, int fid, unsigned long arg0, > unsigned long arg1, unsigned long arg2, > -- > 2.30.2 > > > _______________________________________________ > linux-riscv mailing list > linux-riscv@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-riscv Otherwise, LGTM. Reviewed-by: Atish Patra <atishp@rivosinc.com>
diff --git a/arch/riscv/kernel/sbi.c b/arch/riscv/kernel/sbi.c index f72527fcb347..c839acd668d3 100644 --- a/arch/riscv/kernel/sbi.c +++ b/arch/riscv/kernel/sbi.c @@ -15,11 +15,19 @@ unsigned long sbi_spec_version __ro_after_init = SBI_SPEC_VERSION_DEFAULT; EXPORT_SYMBOL(sbi_spec_version); +static int __sbi_rfence_none(int fid, const struct cpumask *cpu_mask, + unsigned long start, unsigned long size, + unsigned long arg4, unsigned long arg5) +{ + return -EOPNOTSUPP; +} + static void (*__sbi_set_timer)(uint64_t stime) __ro_after_init; static int (*__sbi_send_ipi)(const struct cpumask *cpu_mask) __ro_after_init; static int (*__sbi_rfence)(int fid, const struct cpumask *cpu_mask, unsigned long start, unsigned long size, - unsigned long arg4, unsigned long arg5) __ro_after_init; + unsigned long arg4, unsigned long arg5) + __ro_after_init = __sbi_rfence_none; struct sbiret sbi_ecall(int ext, int fid, unsigned long arg0, unsigned long arg1, unsigned long arg2,
The callback used inside sbi_remote_fence_i is set at sbi probe time to the needed variant. Before that it is a NULL pointer. Some users like the flush_icache_*() functions suggest a generic functionality, that doesn't depend on a specific boot-stage but uses sbi_remote_fence_i as one option to flush other cpu cores. So they definitly shouldn't run into null-pointer dereference issues when called "too early" during boot. So introduce an empty function to be the standard for the __sbi_rfence function pointer until sbi_init has run. Users of sbi_remote_fence_i will have separate code for the local cpu and sbi_init() is called before other cpus are brought up. So there are no other cpus present at the time when the issue might happen. Signed-off-by: Heiko Stuebner <heiko@sntech.de> --- arch/riscv/kernel/sbi.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-)