[PATCH 15/17] lib: utils/irqchip: Use scratch space to save per-HART PLIC pointer
Anup Patel
anup at brainfault.org
Sun Jun 4 22:31:07 PDT 2023
On Wed, May 31, 2023 at 6:42 PM Andrew Jones <ajones at ventanamicro.com> wrote:
>
> On Tue, Apr 25, 2023 at 06:02:28PM +0530, Anup Patel wrote:
> > Instead of using a global array indexed by hartid, we should use
> > scratch space to save per-HART PLIC pointer and PLIC context numbers.
> >
> > Signed-off-by: Anup Patel <apatel at ventanamicro.com>
> > ---
> > lib/utils/irqchip/fdt_irqchip_plic.c | 108 +++++++++++++++++++++------
> > 1 file changed, 86 insertions(+), 22 deletions(-)
> >
> > diff --git a/lib/utils/irqchip/fdt_irqchip_plic.c b/lib/utils/irqchip/fdt_irqchip_plic.c
> > index 605f44a..eb1e412 100644
> > --- a/lib/utils/irqchip/fdt_irqchip_plic.c
> > +++ b/lib/utils/irqchip/fdt_irqchip_plic.c
> > @@ -12,54 +12,97 @@
> > #include <sbi/riscv_io.h>
> > #include <sbi/sbi_error.h>
> > #include <sbi/sbi_heap.h>
> > -#include <sbi/sbi_hartmask.h>
> > +#include <sbi/sbi_scratch.h>
> > #include <sbi_utils/fdt/fdt_helper.h>
> > #include <sbi_utils/irqchip/fdt_irqchip.h>
> > #include <sbi_utils/irqchip/plic.h>
> >
> > -static struct plic_data *plic_hartid2data[SBI_HARTMASK_MAX_BITS];
> > -static int plic_hartid2context[SBI_HARTMASK_MAX_BITS][2] = { { -1 } };
> > +static unsigned long plic_ptr_offset;
> > +
> > +#define plic_get_hart_data_ptr(__scratch) \
> > +({ \
> > + (void *)(*((ulong *)sbi_scratch_offset_ptr((__scratch), \
> > + plic_ptr_offset))); \
> > +})
> > +
> > +#define plic_set_hart_data_ptr(__scratch, __imsic) \
> > +do { \
> > + *((ulong *)sbi_scratch_offset_ptr((__scratch), plic_ptr_offset))\
> > + = (ulong)(__imsic); \
> > +} while (0)
> > +
> > +static unsigned long plic_mcontext_offset;
> > +
> > +#define plic_get_hart_mcontext(__scratch) \
> > +({ \
> > + long __ret = \
> > + *((long *)sbi_scratch_offset_ptr((__scratch), plic_mcontext_offset));\
> > + (__ret - 1); \
> > +})
> > +
> > +#define plic_set_hart_mcontext(__scratch, __mcontext) \
> > +do { \
> > + *((long *)sbi_scratch_offset_ptr((__scratch), plic_mcontext_offset))\
> > + = (long)(__mcontext + 1); \
> > +} while (0)
> > +
> > +static unsigned long plic_scontext_offset;
> > +
> > +#define plic_get_hart_scontext(__scratch) \
> > +({ \
> > + long __ret = \
> > + *((long *)sbi_scratch_offset_ptr((__scratch), plic_scontext_offset));\
> > + (__ret - 1); \
> > +})
> > +
> > +#define plic_set_hart_scontext(__scratch, __scontext) \
> > +do { \
> > + *((long *)sbi_scratch_offset_ptr((__scratch), plic_scontext_offset))\
> > + = (long)(__scontext + 1); \
> > +} while (0)
>
> I guess the +/- 1 stuff is to ensure that the m/scontext offsets can be
> tested with zero to see if they need to be allocated. It'd be nice to
> add a comment explaining it.
This +/-1 stuff is to ensure that if [ms]context is not set then
plic_get_hart_[ms]context() will return -1. This approach
exploits the fact that per-HART scratch space is initialized
to zero.
>
> >
> > void fdt_plic_priority_save(u8 *priority, u32 num)
> > {
> > - struct plic_data *plic = plic_hartid2data[current_hartid()];
> > + struct sbi_scratch *scratch = sbi_scratch_thishart_ptr();
> >
> > - plic_priority_save(plic, priority, num);
> > + plic_priority_save(plic_get_hart_data_ptr(scratch), priority, num);
> > }
> >
> > void fdt_plic_priority_restore(const u8 *priority, u32 num)
> > {
> > - struct plic_data *plic = plic_hartid2data[current_hartid()];
> > + struct sbi_scratch *scratch = sbi_scratch_thishart_ptr();
> >
> > - plic_priority_restore(plic, priority, num);
> > + plic_priority_restore(plic_get_hart_data_ptr(scratch), priority, num);
> > }
> >
> > void fdt_plic_context_save(bool smode, u32 *enable, u32 *threshold, u32 num)
> > {
> > - u32 hartid = current_hartid();
> > + struct sbi_scratch *scratch = sbi_scratch_thishart_ptr();
> >
> > - plic_context_save(plic_hartid2data[hartid],
> > - plic_hartid2context[hartid][smode],
> > + plic_context_save(plic_get_hart_data_ptr(scratch),
> > + smode ? plic_get_hart_scontext(scratch) :
> > + plic_get_hart_mcontext(scratch),
> > enable, threshold, num);
> > }
> >
> > void fdt_plic_context_restore(bool smode, const u32 *enable, u32 threshold,
> > u32 num)
> > {
> > - u32 hartid = current_hartid();
> > + struct sbi_scratch *scratch = sbi_scratch_thishart_ptr();
> >
> > - plic_context_restore(plic_hartid2data[hartid],
> > - plic_hartid2context[hartid][smode],
> > + plic_context_restore(plic_get_hart_data_ptr(scratch),
> > + smode ? plic_get_hart_scontext(scratch) :
> > + plic_get_hart_mcontext(scratch),
> > enable, threshold, num);
> > }
> >
> > static int irqchip_plic_warm_init(void)
> > {
> > - u32 hartid = current_hartid();
> > + struct sbi_scratch *scratch = sbi_scratch_thishart_ptr();
> >
> > - return plic_warm_irqchip_init(plic_hartid2data[hartid],
> > - plic_hartid2context[hartid][0],
> > - plic_hartid2context[hartid][1]);
> > + return plic_warm_irqchip_init(plic_get_hart_data_ptr(scratch),
> > + plic_get_hart_mcontext(scratch),
> > + plic_get_hart_scontext(scratch));
> > }
> >
> > static int irqchip_plic_update_hartid_table(void *fdt, int nodeoff,
> > @@ -67,6 +110,7 @@ static int irqchip_plic_update_hartid_table(void *fdt, int nodeoff,
> > {
> > const fdt32_t *val;
> > u32 phandle, hwirq, hartid;
> > + struct sbi_scratch *scratch;
> > int i, err, count, cpu_offset, cpu_intc_offset;
> >
> > val = fdt_getprop(fdt, nodeoff, "interrupts-extended", &count);
> > @@ -90,16 +134,17 @@ static int irqchip_plic_update_hartid_table(void *fdt, int nodeoff,
> > if (err)
> > continue;
> >
> > - if (SBI_HARTMASK_MAX_BITS <= hartid)
> > + scratch = sbi_hartid_to_scratch(hartid);
> > + if (!scratch)
> > continue;
> >
> > - plic_hartid2data[hartid] = pd;
> > + plic_set_hart_data_ptr(scratch, pd);
> > switch (hwirq) {
> > case IRQ_M_EXT:
> > - plic_hartid2context[hartid][0] = i / 2;
> > + plic_set_hart_mcontext(scratch, i / 2);
> > break;
> > case IRQ_S_EXT:
> > - plic_hartid2context[hartid][1] = i / 2;
> > + plic_set_hart_scontext(scratch, i / 2);
> > break;
> > }
> > }
> > @@ -113,6 +158,24 @@ static int irqchip_plic_cold_init(void *fdt, int nodeoff,
> > int rc;
> > struct plic_data *pd;
> >
> > + if (!plic_ptr_offset) {
> > + plic_ptr_offset = sbi_scratch_alloc_offset(sizeof(ulong));
> > + if (!plic_ptr_offset)
> > + return SBI_ENOMEM;
> > + }
> > +
> > + if (!plic_mcontext_offset) {
> > + plic_mcontext_offset = sbi_scratch_alloc_offset(sizeof(long));
> > + if (!plic_mcontext_offset)
> > + return SBI_ENOMEM;
> > + }
> > +
> > + if (!plic_scontext_offset) {
> > + plic_scontext_offset = sbi_scratch_alloc_offset(sizeof(long));
> > + if (!plic_scontext_offset)
> > + return SBI_ENOMEM;
> > + }
> > +
> > pd = sbi_zalloc(sizeof(*pd));
> > if (!pd)
> > return SBI_ENOMEM;
> > @@ -152,7 +215,8 @@ static void thead_plic_plat_init(struct plic_data *pd)
> >
> > void thead_plic_restore(void)
> > {
> > - struct plic_data *plic = plic_hartid2data[current_hartid()];
> > + struct sbi_scratch *scratch = sbi_scratch_thishart_ptr();
> > + struct plic_data *plic = plic_get_hart_data_ptr(scratch);
> >
> > thead_plic_plat_init(plic);
> > }
> > --
> > 2.34.1
> >
>
> Otherwise,
>
> Reviewed-by: Andrew Jones <ajones at ventanamicro.com>
>
Regards,
Anup
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