[PATCH] riscv: Add riscv_force_qspinlock for early_param
Alexandre Ghiti
alex at ghiti.fr
Mon Dec 16 01:14:57 PST 2024
Hi Guo,
On 14/12/2024 05:35, guoren at kernel.org wrote:
> From: Guo Ren <guoren at linux.alibaba.com>
>
> When CONFIG_RISCV_COMBO_SPINLOCKS is enabled, permit qspinlock
> force enabled. See the Kconfig entry for RISCV_COMBO_SPINLOCKS.
>
> Signed-off-by: Guo Ren <guoren at linux.alibaba.com>
> Signed-off-by: Guo Ren <guoren at kernel.org>
> ---
> Documentation/admin-guide/kernel-parameters.txt | 5 +++++
> arch/riscv/kernel/setup.c | 13 ++++++++++++-
> 2 files changed, 17 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index 3872bc6ec49d..43d0df2922b2 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -5887,6 +5887,11 @@
> [KNL] Disable ring 3 MONITOR/MWAIT feature on supported
> CPUs.
>
> + riscv_force_qspinlock [RISCV, EARLY]
> + When CONFIG_RISCV_COMBO_SPINLOCKS is enabled, permit
> + qspinlock force enabled. See the Kconfig entry for
> + RISCV_COMBO_SPINLOCKS.
> +
> riscv_isa_fallback [RISCV,EARLY]
> When CONFIG_RISCV_ISA_FALLBACK is not enabled, permit
> falling back to detecting extension support by parsing
> diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c
> index 45010e71df86..74b13bc64c9c 100644
> --- a/arch/riscv/kernel/setup.c
> +++ b/arch/riscv/kernel/setup.c
> @@ -247,6 +247,15 @@ static void __init parse_dtb(void)
> #if defined(CONFIG_RISCV_COMBO_SPINLOCKS)
> DEFINE_STATIC_KEY_TRUE(qspinlock_key);
> EXPORT_SYMBOL(qspinlock_key);
> +
> +static bool force_qspinlock;
> +
> +static int __init riscv_force_qspinlock(char *p)
> +{
> + force_qspinlock = true;
> + return 0;
> +}
> +early_param("riscv_force_qspinlock", riscv_force_qspinlock);
> #endif
>
> static void __init riscv_spinlock_init(void)
> @@ -267,7 +276,9 @@ static void __init riscv_spinlock_init(void)
> using_ext = "using Ziccrse";
> }
> #if defined(CONFIG_RISCV_COMBO_SPINLOCKS)
> - else {
> + else if (force_qspinlock) {
> + using_ext = "force";
> + } else {
> static_branch_disable(&qspinlock_key);
> pr_info("Ticket spinlock: enabled\n");
> return;
What's the use case for this early param? To me that implies that a
platform may have another extension which would allow the usage of
qspinlock, so why not listing it in riscv_spinlock_init() instead?
Thanks,
Alex
More information about the linux-riscv
mailing list