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SMP - lazy FPU

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- when a process is migrated to a different CPU it may have an active
  FPU context in the processor registers. We must save it and migrate
  it together with the process.
This commit is contained in:
Tomas Hruby
2010-09-15 14:11:25 +00:00
parent 1f89845bb2
commit 5b8b623765
17 changed files with 142 additions and 60 deletions
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38
kernel/proc.c
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@@ -155,6 +155,23 @@ PUBLIC void proc_init(void)
ip->p_rts_flags |= RTS_PROC_STOP;
set_idle_name(ip->p_name, i);
}
for (rp = BEG_PROC_ADDR; rp < END_PROC_ADDR; ++rp) {
/*
* FXSR requires 16-byte alignment of memory image, but
* unfortunately a.out does not preserve the alignment while
* linking. Thus we have to do manual alignment.
*/
phys_bytes aligned_fp_area;
aligned_fp_area =
(phys_bytes) &rp->p_fpu_state.fpu_image;
if(aligned_fp_area % FPUALIGN) {
aligned_fp_area += FPUALIGN -
(aligned_fp_area % FPUALIGN);
}
rp->p_fpu_state.fpu_save_area_p =
(void *) aligned_fp_area;
}
}
PRIVATE void switch_address_space_idle(void)
@@ -346,7 +363,7 @@ check_misc_flags:
context_stop(proc_addr(KERNEL));
/* If the process isn't the owner of FPU, enable the FPU exception */
if(fpu_owner != p)
if(get_cpulocal_var(fpu_owner) != p)
enable_fpu_exception();
else
disable_fpu_exception();
@@ -1573,6 +1590,7 @@ PUBLIC void proc_no_time(struct proc * p)
PUBLIC void copr_not_available_handler(void)
{
struct proc * p;
struct proc ** local_fpu_owner;
/*
* Disable the FPU exception (both for the kernel and for the process
* once it's scheduled), and initialize or restore the FPU state.
@@ -1583,9 +1601,10 @@ PUBLIC void copr_not_available_handler(void)
p = get_cpulocal_var(proc_ptr);
/* if FPU is not owned by anyone, do not store anything */
if (fpu_owner != NULL) {
assert(fpu_owner != p);
save_fpu(fpu_owner);
local_fpu_owner = get_cpulocal_var_ptr(fpu_owner);
if (*local_fpu_owner != NULL) {
assert(*local_fpu_owner != p);
save_local_fpu(*local_fpu_owner);
}
/*
@@ -1593,12 +1612,17 @@ PUBLIC void copr_not_available_handler(void)
* schedule!
*/
restore_fpu(p);
fpu_owner = p;
*local_fpu_owner = p;
context_stop(proc_addr(KERNEL));
restore_user_context(p);
NOT_REACHABLE;
}
PUBLIC void release_fpu(void) {
fpu_owner = NULL;
PUBLIC void release_fpu(struct proc * p) {
struct proc ** fpu_owner_ptr;
fpu_owner_ptr = get_cpu_var_ptr(p->p_cpu, fpu_owner);
if (*fpu_owner_ptr == p)
*fpu_owner_ptr = NULL;
}