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authorRussell King <rmk@dyn-67.arm.linux.org.uk>2006-06-21 13:31:52 +0100
committerRussell King <rmk+kernel@arm.linux.org.uk>2006-06-22 10:24:18 +0100
commitd6551e884cf66de072b81f8b6d23259462c40baf (patch)
treefd8af193bd045e4b16ce911d392d7ffd109d7284 /arch/arm/kernel
parent52ab3f3dc711eeccbfbcc5d4f5c5d9b9ff59650f (diff)
[ARM] Add thread_notify infrastructure
Some machine classes need to allow VFP support to be built into the kernel, but still allow the kernel to run even though VFP isn't present. Unfortunately, the kernel hard-codes VFP instructions into the thread switch, which prevents this being run-time selectable. Solve this by introducing a notifier which things such as VFP can hook into to be informed of events which affect the VFP subsystem (eg, creation and destruction of threads, switches between threads.) Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/kernel')
-rw-r--r--arch/arm/kernel/entry-armv.S24
-rw-r--r--arch/arm/kernel/iwmmxt.S2
-rw-r--r--arch/arm/kernel/process.c24
3 files changed, 22 insertions, 28 deletions
diff --git a/arch/arm/kernel/entry-armv.S b/arch/arm/kernel/entry-armv.S
index ab8e600c18c..86c92523a34 100644
--- a/arch/arm/kernel/entry-armv.S
+++ b/arch/arm/kernel/entry-armv.S
@@ -20,6 +20,7 @@
#include <asm/glue.h>
#include <asm/vfpmacros.h>
#include <asm/arch/entry-macro.S>
+#include <asm/thread_notify.h>
#include "entry-header.S"
@@ -560,10 +561,8 @@ ENTRY(__switch_to)
add ip, r1, #TI_CPU_SAVE
ldr r3, [r2, #TI_TP_VALUE]
stmia ip!, {r4 - sl, fp, sp, lr} @ Store most regs on stack
-#ifndef CONFIG_MMU
- add r2, r2, #TI_CPU_DOMAIN
-#else
- ldr r6, [r2, #TI_CPU_DOMAIN]!
+#ifdef CONFIG_MMU
+ ldr r6, [r2, #TI_CPU_DOMAIN]
#endif
#if __LINUX_ARM_ARCH__ >= 6
#ifdef CONFIG_CPU_32v6K
@@ -585,21 +584,20 @@ ENTRY(__switch_to)
#ifdef CONFIG_MMU
mcr p15, 0, r6, c3, c0, 0 @ Set domain register
#endif
-#ifdef CONFIG_VFP
- @ Always disable VFP so we can lazily save/restore the old
- @ state. This occurs in the context of the previous thread.
- VFPFMRX r4, FPEXC
- bic r4, r4, #FPEXC_ENABLE
- VFPFMXR FPEXC, r4
-#endif
#if defined(CONFIG_IWMMXT)
bl iwmmxt_task_switch
#elif defined(CONFIG_CPU_XSCALE)
- add r4, r2, #40 @ cpu_context_save->extra
+ add r4, r2, #TI_CPU_DOMAIN + 40 @ cpu_context_save->extra
ldmib r4, {r4, r5}
mar acc0, r4, r5
#endif
- ldmib r2, {r4 - sl, fp, sp, pc} @ Load all regs saved previously
+ mov r5, r0
+ add r4, r2, #TI_CPU_SAVE
+ ldr r0, =thread_notify_head
+ mov r1, #THREAD_NOTIFY_SWITCH
+ bl atomic_notifier_call_chain
+ mov r0, r5
+ ldmia r4, {r4 - sl, fp, sp, pc} @ Load all regs saved previously
__INIT
diff --git a/arch/arm/kernel/iwmmxt.S b/arch/arm/kernel/iwmmxt.S
index 24c7b0477a0..af9e0ae952d 100644
--- a/arch/arm/kernel/iwmmxt.S
+++ b/arch/arm/kernel/iwmmxt.S
@@ -285,7 +285,7 @@ ENTRY(iwmmxt_task_switch)
bne 1f @ yes: block them for next task
ldr r5, =concan_owner
- add r6, r2, #(TI_IWMMXT_STATE - TI_CPU_DOMAIN) @ get next task Concan save area
+ add r6, r2, #TI_IWMMXT_STATE @ get next task Concan save area
ldr r5, [r5] @ get current Concan owner
teq r5, r6 @ next task owns it?
movne pc, lr @ no: leave Concan disabled
diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c
index 17c38dbf2f3..e1c77ee885a 100644
--- a/arch/arm/kernel/process.c
+++ b/arch/arm/kernel/process.c
@@ -33,6 +33,7 @@
#include <asm/leds.h>
#include <asm/processor.h>
#include <asm/system.h>
+#include <asm/thread_notify.h>
#include <asm/uaccess.h>
#include <asm/mach/time.h>
@@ -338,13 +339,9 @@ void exit_thread(void)
{
}
-static void default_fp_init(union fp_state *fp)
-{
- memset(fp, 0, sizeof(union fp_state));
-}
+ATOMIC_NOTIFIER_HEAD(thread_notify_head);
-void (*fp_init)(union fp_state *) = default_fp_init;
-EXPORT_SYMBOL(fp_init);
+EXPORT_SYMBOL_GPL(thread_notify_head);
void flush_thread(void)
{
@@ -353,22 +350,21 @@ void flush_thread(void)
memset(thread->used_cp, 0, sizeof(thread->used_cp));
memset(&tsk->thread.debug, 0, sizeof(struct debug_info));
+ memset(&thread->fpstate, 0, sizeof(union fp_state));
+
+ thread_notify(THREAD_NOTIFY_FLUSH, thread);
#if defined(CONFIG_IWMMXT)
iwmmxt_task_release(thread);
#endif
- fp_init(&thread->fpstate);
-#if defined(CONFIG_VFP)
- vfp_flush_thread(&thread->vfpstate);
-#endif
}
void release_thread(struct task_struct *dead_task)
{
-#if defined(CONFIG_VFP)
- vfp_release_thread(&task_thread_info(dead_task)->vfpstate);
-#endif
+ struct thread_info *thread = task_thread_info(dead_task);
+
+ thread_notify(THREAD_NOTIFY_RELEASE, thread);
#if defined(CONFIG_IWMMXT)
- iwmmxt_task_release(task_thread_info(dead_task));
+ iwmmxt_task_release(thread);
#endif
}