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authorAndrew Waterman <waterman@cs.berkeley.edu>2016-02-23 12:46:56 -0800
committerAndrew Waterman <waterman@cs.berkeley.edu>2016-02-23 12:46:56 -0800
commit4991166b0c9a676ead9eb92980db646c680c097b (patch)
treef67d78f678e93ddb4aee6072744ccb0d8595bc98 /pk
parentbf9ee5ca114921718da280de46046dbc43722641 (diff)
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Use simpler, less-general IPI interface
No need for active messages in this context.
Diffstat (limited to 'pk')
-rw-r--r--pk/mtrap.c84
-rw-r--r--pk/mtrap.h14
2 files changed, 44 insertions, 54 deletions
diff --git a/pk/mtrap.c b/pk/mtrap.c
index ca0f890..c7cad95 100644
--- a/pk/mtrap.c
+++ b/pk/mtrap.c
@@ -198,23 +198,27 @@ static uintptr_t mcall_dev_resp()
// only clear SSIP if no other events are pending
clear_csr(mip, MIP_SSIP);
mb();
- if (HLS()->ipi_pending)
+ if (HLS()->ipi_pending & IPI_SOFT)
set_csr(mip, MIP_SSIP);
}
}
return (uintptr_t)m;
}
-static uintptr_t mcall_send_ipi(uintptr_t recipient)
+static void send_ipi(uintptr_t recipient, int event)
{
- if (recipient >= num_harts)
- return -1;
-
- if (atomic_swap(&OTHER_HLS(recipient)->ipi_pending, 1) == 0) {
+ if ((atomic_or(&OTHER_HLS(recipient)->ipi_pending, event) & event) == 0) {
mb();
OTHER_HLS(recipient)->csrs[CSR_MIPI] = 1;
}
+}
+static uintptr_t mcall_send_ipi(uintptr_t recipient)
+{
+ if (recipient >= num_harts)
+ return -1;
+
+ send_ipi(recipient, IPI_SOFT);
return 0;
}
@@ -251,64 +255,52 @@ static uintptr_t mcall_set_timer(unsigned long long when)
void software_interrupt()
{
clear_csr(mip, MIP_MSIP);
- __sync_synchronize();
+ mb();
+ int ipi_pending = atomic_swap(&HLS()->ipi_pending, 0);
- if (HLS()->ipi_pending)
+ if (ipi_pending & IPI_SOFT)
set_csr(mip, MIP_SSIP);
- if (HLS()->rpc_func) {
- __sync_synchronize();
- rpc_func_t f = *HLS()->rpc_func;
- (f.func)(f.arg);
- __sync_synchronize();
- HLS()->rpc_func = (void*)1;
- }
+ if (ipi_pending & IPI_FENCE_I)
+ asm volatile ("fence.i");
+
+ if (ipi_pending & IPI_SFENCE_VM)
+ asm volatile ("sfence.vm");
}
-static void call_func_all(uintptr_t* mask, void (*func)(uintptr_t), uintptr_t arg)
+static void send_ipi_many(uintptr_t* pmask, int event)
{
- kassert(MAX_HARTS <= 8*sizeof(*mask));
- kassert(supervisor_paddr_valid((uintptr_t)mask, sizeof(uintptr_t)));
-
- rpc_func_t f = {func, arg};
-
- uintptr_t harts = *mask;
- for (ssize_t i = num_harts-1; i >= 0; i--) {
- if (((harts >> i) & 1) == 0)
- continue;
+ kassert(MAX_HARTS <= 8 * sizeof(*pmask));
+ uintptr_t mask = -1;
+ if (pmask) {
+ kassert(supervisor_paddr_valid((uintptr_t)pmask, sizeof(uintptr_t)));
+ mask = *pmask;
+ }
- if (HLS()->hart_id == i) {
- func(arg);
- } else {
- rpc_func_t** p = &OTHER_HLS(i)->rpc_func;
- uintptr_t* mipi = &OTHER_HLS(i)->csrs[CSR_MIPI];
+ // send IPIs to everyone
+ for (ssize_t i = num_harts-1; i >= 0; i--)
+ if ((mask >> i) & 1)
+ send_ipi(i, event);
- while (atomic_cas(p, 0, &f) != &f)
+ // wait until all events have been handled.
+ // prevent deadlock while spinning by handling any IPIs from other harts.
+ for (ssize_t i = num_harts-1; i >= 0; i--)
+ if ((mask >> i) & 1)
+ while (OTHER_HLS(i)->ipi_pending & event)
software_interrupt();
-
- __sync_synchronize();
- *mipi = 1;
- __sync_synchronize();
-
- while (atomic_cas(p, (void*)1, 0) != (void*)1)
- ;
- }
- }
}
static uintptr_t mcall_remote_sfence_vm(uintptr_t* hart_mask, uintptr_t asid)
{
- void sfence_vm(uintptr_t arg) {
- asm volatile ("csrrw %0, sasid, %0; sfence.vm; csrw sasid, %0" : "+r"(arg));
- }
- call_func_all(hart_mask, &sfence_vm, asid);
+ // ignore the ASID and do a global flush.
+ // this allows us to avoid queueing a message.
+ send_ipi_many(hart_mask, IPI_SFENCE_VM);
return 0;
}
static uintptr_t mcall_remote_fence_i(uintptr_t* hart_mask)
{
- void fence_i(uintptr_t arg) { asm volatile ("fence.i"); }
- call_func_all(hart_mask, &fence_i, 0);
+ send_ipi_many(hart_mask, IPI_FENCE_I);
return 0;
}
diff --git a/pk/mtrap.h b/pk/mtrap.h
index 64caaab..99308a2 100644
--- a/pk/mtrap.h
+++ b/pk/mtrap.h
@@ -163,22 +163,20 @@ static inline int xlen()
}
typedef struct {
- void (*func)(uintptr_t);
- uintptr_t arg;
-} rpc_func_t;
-
-typedef struct {
sbi_device_message* device_request_queue_head;
size_t device_request_queue_size;
sbi_device_message* device_response_queue_head;
sbi_device_message* device_response_queue_tail;
- rpc_func_t* rpc_func;
- uintptr_t* csrs;
+ volatile uintptr_t* csrs;
int hart_id;
- int ipi_pending;
+ volatile int ipi_pending;
} hls_t;
+#define IPI_SOFT 0x1
+#define IPI_FENCE_I 0x2
+#define IPI_SFENCE_VM 0x4
+
void hls_init(uint32_t hart_id, uintptr_t* csrs);
#define MACHINE_STACK_TOP() ({ \