sh: Fix up DSP context save/restore.
There were a number of issues with the DSP context save/restore code,
mostly left-over relics from when it was introduced on SH3-DSP with
little follow-up testing, resulting in things like task_pt_dspregs()
referencing incorrect state on the stack.
This follows the MIPS convention of tracking the DSP state in the
thread_struct and handling the state save/restore in switch_to() and
finish_arch_switch() respectively. The regset interface is also updated,
which allows us to finally be rid of task_pt_dspregs() and the special
cased task_pt_regs().
Signed-off-by: Michael Trimarchi <michael@evidence.eu.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
diff --git a/arch/sh/kernel/cpu/sh3/entry.S b/arch/sh/kernel/cpu/sh3/entry.S
index 55da0ff..3cb531f 100644
--- a/arch/sh/kernel/cpu/sh3/entry.S
+++ b/arch/sh/kernel/cpu/sh3/entry.S
@@ -254,40 +254,6 @@
lds k2, pr ! restore pr
!
-#ifdef CONFIG_SH_DSP
- mov.l @r15+, k0 ! DSP mode marker
- mov.l 5f, k1
- cmp/eq k0, k1 ! Do we have a DSP stack frame?
- bf skip_restore
-
- stc sr, k0 ! Enable CPU DSP mode
- or k1, k0 ! (within kernel it may be disabled)
- ldc k0, sr
- mov r2, k0 ! Backup r2
-
- ! Restore DSP registers from stack
- mov r15, r2
- movs.l @r2+, a1
- movs.l @r2+, a0g
- movs.l @r2+, a1g
- movs.l @r2+, m0
- movs.l @r2+, m1
- mov r2, r15
-
- lds.l @r15+, a0
- lds.l @r15+, x0
- lds.l @r15+, x1
- lds.l @r15+, y0
- lds.l @r15+, y1
- lds.l @r15+, dsr
- ldc.l @r15+, rs
- ldc.l @r15+, re
- ldc.l @r15+, mod
-
- mov k0, r2 ! Restore r2
-skip_restore:
-#endif
- !
! Calculate new SR value
mov k3, k2 ! original SR value
mov #0xf0, k1
@@ -358,7 +324,7 @@
add k0, k4
0:
! Setup stack and save DSP context (k0 contains original r15 on return)
- bsr prepare_stack_save_dsp
+ bsr prepare_stack
nop
! Save registers / Switch to bank 0
@@ -374,15 +340,14 @@
1: .long EXPEVT
#endif
-! prepare_stack_save_dsp()
+! prepare_stack()
! - roll back gRB
! - switch to kernel stack
-! - save DSP
! k0 returns original sp (after roll back)
! k1 trashed
! k2 trashed
-prepare_stack_save_dsp:
+prepare_stack:
#ifdef CONFIG_GUSA
! Check for roll back gRB (User and Kernel)
mov r15, k0
@@ -416,47 +381,9 @@
mov k1, r15 ! change to kernel stack
!
1:
-#ifdef CONFIG_SH_DSP
- ! Save DSP context if needed
- stc sr, k1
- mov #0x10, k2
- shll8 k2 ! DSP=1 (0x00001000)
- tst k2, k1 ! Check if in DSP mode (passed in k2)
- bt/s skip_save
- mov #0, k1 ! Set marker for no stack frame
-
- mov k2, k1 ! Save has-frame marker
-
- ! Save DSP registers on stack
- stc.l mod, @-r15
- stc.l re, @-r15
- stc.l rs, @-r15
- sts.l dsr, @-r15
- sts.l y1, @-r15
- sts.l y0, @-r15
- sts.l x1, @-r15
- sts.l x0, @-r15
- sts.l a0, @-r15
-
- ! GAS is broken, does not generate correct "movs.l Ds,@-As" instr.
-
- ! FIXME: Make sure that this is still the case with newer toolchains,
- ! as we're not at all interested in supporting ancient toolchains at
- ! this point. -- PFM.
-
- mov r15, k2
- .word 0xf653 ! movs.l a1, @-r2
- .word 0xf6f3 ! movs.l a0g, @-r2
- .word 0xf6d3 ! movs.l a1g, @-r2
- .word 0xf6c3 ! movs.l m0, @-r2
- .word 0xf6e3 ! movs.l m1, @-r2
- mov k2, r15
-
-skip_save:
- mov.l k1, @-r15 ! Push DSP mode marker onto stack
-#endif
rts
nop
+
!
! 0x400: Instruction and Data TLB miss exception vector
!
@@ -468,7 +395,7 @@
mova exception_data, k0
! Setup stack and save DSP context (k0 contains original r15 on return)
- bsr prepare_stack_save_dsp
+ bsr prepare_stack
PREF(k0)
! Save registers / Switch to bank 0
@@ -572,7 +499,7 @@
mova exception_data, k0
! Setup stack and save DSP context (k0 contains original r15 on return)
- bsr prepare_stack_save_dsp
+ bsr prepare_stack
PREF(k0)
! Save registers / Switch to bank 0
diff --git a/arch/sh/kernel/process_32.c b/arch/sh/kernel/process_32.c
index ddafbbb..0747fab 100644
--- a/arch/sh/kernel/process_32.c
+++ b/arch/sh/kernel/process_32.c
@@ -176,14 +176,26 @@
{
struct thread_info *ti = task_thread_info(p);
struct pt_regs *childregs;
-#if defined(CONFIG_SH_FPU)
+#if defined(CONFIG_SH_FPU) || defined(CONFIG_SH_DSP)
struct task_struct *tsk = current;
+#endif
+#if defined(CONFIG_SH_FPU)
unlazy_fpu(tsk, regs);
p->thread.fpu = tsk->thread.fpu;
copy_to_stopped_child_used_math(p);
#endif
+#if defined(CONFIG_SH_DSP)
+ if (is_dsp_enabled(tsk)) {
+ /* We can use the __save_dsp or just copy the struct:
+ * __save_dsp(p);
+ * p->thread.dsp_status.status |= SR_DSP
+ */
+ p->thread.dsp_status = tsk->thread.dsp_status;
+ }
+#endif
+
childregs = task_pt_regs(p);
*childregs = *regs;
diff --git a/arch/sh/kernel/ptrace_32.c b/arch/sh/kernel/ptrace_32.c
index 29ca09d..f7b22dd 100644
--- a/arch/sh/kernel/ptrace_32.c
+++ b/arch/sh/kernel/ptrace_32.c
@@ -200,7 +200,8 @@
unsigned int pos, unsigned int count,
void *kbuf, void __user *ubuf)
{
- const struct pt_dspregs *regs = task_pt_dspregs(target);
+ const struct pt_dspregs *regs =
+ (struct pt_dspregs *)&target->thread.dsp_status.dsp_regs;
int ret;
ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, regs,
@@ -217,7 +218,8 @@
unsigned int pos, unsigned int count,
const void *kbuf, const void __user *ubuf)
{
- struct pt_dspregs *regs = task_pt_dspregs(target);
+ struct pt_dspregs *regs =
+ (struct pt_dspregs *)&target->thread.dsp_status.dsp_regs;
int ret;
ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, regs,
diff --git a/arch/sh/kernel/traps_32.c b/arch/sh/kernel/traps_32.c
index 60dcf87..30ca9c5 100644
--- a/arch/sh/kernel/traps_32.c
+++ b/arch/sh/kernel/traps_32.c
@@ -664,6 +664,8 @@
if (is_dsp_inst(regs)) {
/* Enable DSP mode, and restart instruction. */
regs->sr |= SR_DSP;
+ /* Save DSP mode */
+ tsk->thread.dsp_status.status |= SR_DSP;
return;
}
#endif