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rus_vm_fault: always use a packet on the stack

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There are valid use cases where a remote page fault has no available
thread data/packet available to use, e.g. when device driver threads
need to access the data (BXI).

Do the per thread data lookup to use the right channel/tid if available,
and use mcctrl_ikc_send_wait with a new message number directly.

The fault is no longer handled in mckernel syscall forwarding code but
in the ikc handler directly in irq, this should be ok because page
faults are interrupts anyway so the code should be irq-safe.

Change-Id: Ie60f413cdaee6c1a824b4a2c93637899cb9bf9c9
This commit is contained in:
Dominique Martinet
2018-12-25 10:58:58 +01:00
committed by Dominique Martinet
parent 8074445d59
commit a5d5baf8a8
7 changed files with 150 additions and 303 deletions
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39
kernel/syscall.c
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@ -241,7 +241,7 @@ long do_syscall(struct syscall_request *req, int cpu)
#define STATUS_IN_PROGRESS 0
#define STATUS_COMPLETED 1
#define STATUS_PAGE_FAULT 3
#define STATUS_SYACALL 4
#define STATUS_SYSCALL 4
while (res.status != STATUS_COMPLETED) {
while (res.status == STATUS_IN_PROGRESS) {
struct cpu_local_var *v;
@ -295,42 +295,7 @@ long do_syscall(struct syscall_request *req, int cpu)
cpu_restore_interrupt(flags);
}
if (res.status == STATUS_PAGE_FAULT) {
#ifdef PROFILE_ENABLE
/* We cannot use thread->profile_start_ts here because the
* caller may be utilizing it already */
unsigned long t_s = 0;
if (thread->profile) {
t_s = rdtsc();
}
#endif // PROFILE_ENABLE
dkprintf("STATUS_PAGE_FAULT in syscall, pid: %d\n",
cpu_local_var(current)->proc->pid);
dkprintf("remote page fault,va=%lx,reason=%x\n", res.fault_address, res.fault_reason|PF_POPULATE);
error = page_fault_process_vm(thread->vm,
(void *)res.fault_address,
res.fault_reason|PF_POPULATE);
/* send result */
req2.number = __NR_mmap;
#define PAGER_RESUME_PAGE_FAULT 0x0101
req2.args[0] = PAGER_RESUME_PAGE_FAULT;
req2.args[1] = error;
/* The current thread is the requester and only the waiting thread
* may serve the request */
req2.rtid = cpu_local_var(current)->tid;
req2.ttid = res.stid;
res.req_thread_status = IHK_SCD_REQ_THREAD_SPINNING;
send_syscall(&req2, cpu, &res);
#ifdef PROFILE_ENABLE
profile_event_add(PROFILE_remote_page_fault,
(rdtsc() - t_s));
#endif // PROFILE_ENABLE
}
if (res.status == STATUS_SYACALL) {
if (res.status == STATUS_SYSCALL) {
struct syscall_request *requestp;
struct syscall_request request;
int num;