ldr r4, [r3, r11, lsl #2] @ vfp_current_hw_state pointer
bic r5, r1, #FPEXC_EX @ make sure exceptions are disabled
cmp r4, r10 @ this thread owns the hw context?
-#ifndef CONFIG_SMP
- @ For UP, checking that this thread owns the hw context is
- @ sufficient to determine that the hardware state is valid.
beq vfp_hw_state_valid
- @ On UP, we lazily save the VFP context. As a different
- @ thread wants ownership of the VFP hardware, save the old
- @ state if there was a previous (valid) owner.
-
VFPFMXR FPEXC, r5 @ enable VFP, disable any pending
@ exceptions, so we can get at the
@ rest of it
+#ifndef CONFIG_SMP
+ @ Save out the current registers to the old thread state
+ @ No need for SMP since this is not done lazily
+
DBGSTR1 "save old state %p", r4
- cmp r4, #0 @ if the vfp_current_hw_state is NULL
- beq vfp_reload_hw @ then the hw state needs reloading
+ cmp r4, #0
+ beq no_old_VFP_process
VFPFSTMIA r4, r5 @ save the working registers
VFPFMRX r5, FPSCR @ current status
#ifndef CONFIG_CPU_FEROCEON
1:
#endif
stmia r4, {r1, r5, r6, r8} @ save FPEXC, FPSCR, FPINST, FPINST2
-vfp_reload_hw:
-
-#else
- @ For SMP, if this thread does not own the hw context, then we
- @ need to reload it. No need to save the old state as on SMP,
- @ we always save the state when we switch away from a thread.
- bne vfp_reload_hw
-
- @ This thread has ownership of the current hardware context.
- @ However, it may have been migrated to another CPU, in which
- @ case the saved state is newer than the hardware context.
- @ Check this by looking at the CPU number which the state was
- @ last loaded onto.
- ldr ip, [r10, #VFP_CPU]
- teq ip, r11
- beq vfp_hw_state_valid
-
-vfp_reload_hw:
- @ We're loading this threads state into the VFP hardware. Update
- @ the CPU number which contains the most up to date VFP context.
- str r11, [r10, #VFP_CPU]
-
- VFPFMXR FPEXC, r5 @ enable VFP, disable any pending
- @ exceptions, so we can get at the
- @ rest of it
+ @ and point r4 at the word at the
+ @ start of the register dump
#endif
+no_old_VFP_process:
DBGSTR1 "load state %p", r10
str r10, [r3, r11, lsl #2] @ update the vfp_current_hw_state pointer
@ Load the saved state back into the VFP
void (*vfp_vector)(void) = vfp_null_entry;
-/*
- * Dual-use variable.
- * Used in startup: set to non-zero if VFP checks fail
- * After startup, holds VFP architecture
- */
-unsigned int VFP_arch;
-
/*
* The pointer to the vfpstate structure of the thread which currently
* owns the context held in the VFP hardware, or NULL if the hardware
* context is invalid.
- *
- * For UP, this is sufficient to tell which thread owns the VFP context.
- * However, for SMP, we also need to check the CPU number stored in the
- * saved state too to catch migrations.
*/
union vfp_state *vfp_current_hw_state[NR_CPUS];
/*
- * Is 'thread's most up to date state stored in this CPUs hardware?
- * Must be called from non-preemptible context.
- */
-static bool vfp_state_in_hw(unsigned int cpu, struct thread_info *thread)
-{
-#ifdef CONFIG_SMP
- if (thread->vfpstate.hard.cpu != cpu)
- return false;
-#endif
- return vfp_current_hw_state[cpu] == &thread->vfpstate;
-}
-
-/*
- * Force a reload of the VFP context from the thread structure. We do
- * this by ensuring that access to the VFP hardware is disabled, and
- * clear last_VFP_context. Must be called from non-preemptible context.
+ * Dual-use variable.
+ * Used in startup: set to non-zero if VFP checks fail
+ * After startup, holds VFP architecture
*/
-static void vfp_force_reload(unsigned int cpu, struct thread_info *thread)
-{
- if (vfp_state_in_hw(cpu, thread)) {
- fmxr(FPEXC, fmrx(FPEXC) & ~FPEXC_EN);
- vfp_current_hw_state[cpu] = NULL;
- }
-#ifdef CONFIG_SMP
- thread->vfpstate.hard.cpu = NR_CPUS;
-#endif
-}
+unsigned int VFP_arch;
/*
* Per-thread VFP initialization.
vfp->hard.fpexc = FPEXC_EN;
vfp->hard.fpscr = FPSCR_ROUND_NEAREST;
-#ifdef CONFIG_SMP
- vfp->hard.cpu = NR_CPUS;
-#endif
/*
* Disable VFP to ensure we initialize it first. We must ensure
vfp_sync_hwstate(parent);
thread->vfpstate = parent->vfpstate;
-#ifdef CONFIG_SMP
- thread->vfpstate.hard.cpu = NR_CPUS;
-#endif
}
/*
* case the thread migrates to a different CPU. The
* restoring is done lazily.
*/
- if ((fpexc & FPEXC_EN) && vfp_current_hw_state[cpu])
+ if ((fpexc & FPEXC_EN) && vfp_current_hw_state[cpu]) {
vfp_save_state(vfp_current_hw_state[cpu], fpexc);
+ vfp_current_hw_state[cpu]->hard.cpu = cpu;
+ }
+ /*
+ * Thread migration, just force the reloading of the
+ * state on the new CPU in case the VFP registers
+ * contain stale data.
+ */
+ if (thread->vfpstate.hard.cpu != cpu)
+ vfp_current_hw_state[cpu] = NULL;
#endif
/*
static inline void vfp_pm_init(void) { }
#endif /* CONFIG_PM */
-/*
- * Ensure that the VFP state stored in 'thread->vfpstate' is up to date
- * with the hardware state.
- */
void vfp_sync_hwstate(struct thread_info *thread)
{
unsigned int cpu = get_cpu();
- if (vfp_state_in_hw(cpu, thread)) {
+ /*
+ * If the thread we're interested in is the current owner of the
+ * hardware VFP state, then we need to save its state.
+ */
+ if (vfp_current_hw_state[cpu] == &thread->vfpstate) {
u32 fpexc = fmrx(FPEXC);
/*
put_cpu();
}
-/* Ensure that the thread reloads the hardware VFP state on the next use. */
void vfp_flush_hwstate(struct thread_info *thread)
{
unsigned int cpu = get_cpu();
- vfp_force_reload(cpu, thread);
+ /*
+ * If the thread we're interested in is the current owner of the
+ * hardware VFP state, then we need to save its state.
+ */
+ if (vfp_current_hw_state[cpu] == &thread->vfpstate) {
+ u32 fpexc = fmrx(FPEXC);
+ fmxr(FPEXC, fpexc & ~FPEXC_EN);
+
+ /*
+ * Set the context to NULL to force a reload the next time
+ * the thread uses the VFP.
+ */
+ vfp_current_hw_state[cpu] = NULL;
+ }
+
+#ifdef CONFIG_SMP
+ /*
+ * For SMP we still have to take care of the case where the thread
+ * migrates to another CPU and then back to the original CPU on which
+ * the last VFP user is still the same thread. Mark the thread VFP
+ * state as belonging to a non-existent CPU so that the saved one will
+ * be reloaded in the above case.
+ */
+ thread->vfpstate.hard.cpu = NR_CPUS;
+#endif
put_cpu();
}
void *hcpu)
{
if (action == CPU_DYING || action == CPU_DYING_FROZEN) {
- vfp_force_reload((long)hcpu, current_thread_info());
+ unsigned int cpu = (long)hcpu;
+ vfp_current_hw_state[cpu] = NULL;
} else if (action == CPU_STARTING || action == CPU_STARTING_FROZEN)
vfp_enable(NULL);
return NOTIFY_OK;
projects / firefly-linux-kernel-4.4.55.git / commitdiff