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lib: Improve delivery of SBI_IPI_EVENT_HALT

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When sbi_ipi_send_many gets called with the current hartid
included on pmask (or when pmask is NULL), and we send
a HALT event, since the for loop works sequentially over
all hartids on the mask, we may send a HALT event to the
current hart before the loop finishes. So we will halt
the current hart before it can deliver a HALT IPI to the
rest and some harts will remain active.

Make sure we send an IPI to the current hart after we've
finished with everybody else.

Signed-off-by: Nick Kossifidis <mick@ics.forth.gr>
This commit is contained in:
Nick Kossifidis
2019-02-17 09:00:20 +02:00
committed by Anup Patel
parent 51e543511a
commit 918c1354b7
1 changed files with 34 additions and 13 deletions
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47
lib/sbi_ipi.c
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@@ -5,6 +5,7 @@
*
* Authors:
* Anup Patel <anup.patel@wdc.com>
* Nick Kossifidis <mick@ics.forth.gr
*/
#include <sbi/riscv_asm.h>
@@ -18,28 +19,48 @@
#include <sbi/sbi_timer.h>
#include <sbi/sbi_unpriv.h>
static int sbi_ipi_send(struct sbi_scratch *scratch, u32 hartid, u32 event)
{
struct sbi_scratch *remote_scratch = NULL;
struct sbi_platform *plat = sbi_platform_ptr(scratch);
if (sbi_platform_hart_disabled(plat, hartid))
return -1;
/* Set IPI type on remote hart's scratch area and
* trigger the interrupt
*/
remote_scratch = sbi_hart_id_to_scratch(scratch, hartid);
atomic_raw_set_bit(event, &remote_scratch->ipi_type);
mb();
sbi_platform_ipi_send(plat, hartid);
if (event != SBI_IPI_EVENT_SOFT)
sbi_platform_ipi_sync(plat, hartid);
return 0;
}
int sbi_ipi_send_many(struct sbi_scratch *scratch,
ulong *pmask, u32 event)
{
ulong i, m;
struct sbi_scratch *oth;
ulong mask = sbi_hart_available_mask();
struct sbi_platform *plat = sbi_platform_ptr(scratch);
u32 hartid = sbi_current_hartid();
if (pmask)
mask &= load_ulong(pmask, csr_read(CSR_MEPC));
/* send IPIs to everyone */
for (i = 0, m = mask; m; i++, m >>= 1) {
if ((m & 1) && !sbi_platform_hart_disabled(plat, i)) {
oth = sbi_hart_id_to_scratch(scratch, i);
atomic_raw_set_bit(event, &oth->ipi_type);
mb();
sbi_platform_ipi_send(plat, i);
if (event != SBI_IPI_EVENT_SOFT)
sbi_platform_ipi_sync(plat, i);
}
}
/* send IPIs to every other hart on the set */
for (i = 0, m = mask; m > 0; m >>= ++i)
if ((m & 1UL) && (i != hartid))
sbi_ipi_send(scratch, i, event);
/* If the current hart is on the set, send an IPI
* to it as well
*/
if (mask & (1UL << hartid))
sbi_ipi_send(scratch, hartid, event);
return 0;
}