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/include/asm/processor_32.h b/arch/sh/include/asm/processor_32.h
index efdd78a53b111f493f6f62280c1d9c19d3c6791d..9a8714945dc9b98ce25e19b029f4a0c5d14cdbc0 100644 (file)
--- a/arch/sh/include/asm/processor_32.h
+++ b/arch/sh/include/asm/processor_32.h
@@ -57,6 +57,14 @@ asmlinkage void __init sh_cpu_init(void);
 #define SR_IMASK       0x000000f0
 #define SR_FD          0x00008000
 
+/*
+ * DSP structure and data
+ */
+struct sh_dsp_struct {
+       unsigned long dsp_regs[14];
+       long status;
+};
+
 /*
  * FPU structure and data
  */
@@ -96,6 +104,11 @@ struct thread_struct {
 
        /* floating point info */
        union sh_fpu_union fpu;
+
+#ifdef CONFIG_SH_DSP
+       /* Dsp status information */
+       struct sh_dsp_struct dsp_status;
+#endif
 };
 
 /* Count of active tasks with UBC settings */

diff --git a/arch/sh/include/asm/ptrace.h b/arch/sh/include/asm/ptrace.h
index 81c6568fdb3ed5ede3287f8f26dee1b21b9848f6..d3f6caa936b02fb81b7e974504f0898c9cfca51b 100644 (file)
--- a/arch/sh/include/asm/ptrace.h
+++ b/arch/sh/include/asm/ptrace.h
@@ -119,16 +119,8 @@ struct task_struct;
 extern void user_enable_single_step(struct task_struct *);
 extern void user_disable_single_step(struct task_struct *);
 
-#ifdef CONFIG_SH_DSP
-#define task_pt_regs(task) \
-       ((struct pt_regs *) (task_stack_page(task) + THREAD_SIZE \
-                - sizeof(struct pt_dspregs)) - 1)
-#define task_pt_dspregs(task) \
-       ((struct pt_dspregs *) (task_stack_page(task) + THREAD_SIZE) - 1)
-#else
 #define task_pt_regs(task) \
        ((struct pt_regs *) (task_stack_page(task) + THREAD_SIZE) - 1)
-#endif
 
 static inline unsigned long profile_pc(struct pt_regs *regs)
 {

diff --git a/arch/sh/include/asm/system_32.h b/arch/sh/include/asm/system_32.h
index a726d5d07277a6d53e91b90d743201c10f4fd52d..240b31e1142c06f9d254e6c17936d282aef21230 100644 (file)
--- a/arch/sh/include/asm/system_32.h
+++ b/arch/sh/include/asm/system_32.h
@@ -3,59 +3,135 @@
 
 #include <linux/types.h>
 
+#ifdef CONFIG_SH_DSP
+
+#define is_dsp_enabled(tsk)                                            \
+       (!!(tsk->thread.dsp_status.status & SR_DSP))
+
+#define __restore_dsp(tsk)                                             \
+do {                                                                   \
+       register u32 *__ts2 __asm__ ("r2") =                            \
+                       (u32 *)&tsk->thread.dsp_status;                 \
+       __asm__ __volatile__ (                                          \
+               ".balign 4\n\t"                                         \
+               "movs.l @r2+, a1\n\t"                                   \
+               "movs.l @r2+, a0g\n\t"                                  \
+               "movs.l @r2+, a1g\n\t"                                  \
+               "movs.l @r2+, m0\n\t"                                   \
+               "movs.l @r2+, m1\n\t"                                   \
+               "movs.l @r2+, a0\n\t"                                   \
+               "movs.l @r2+, x0\n\t"                                   \
+               "movs.l @r2+, x1\n\t"                                   \
+               "movs.l @r2+, y0\n\t"                                   \
+               "movs.l @r2+, y1\n\t"                                   \
+               "lds.l  @r2+, dsr\n\t"                                  \
+               "ldc.l  @r2+, rs\n\t"                                   \
+               "ldc.l  @r2+, re\n\t"                                   \
+               "ldc.l  @r2+, mod\n\t"                                  \
+               : : "r" (__ts2));                                       \
+} while (0)
+
+
+#define __save_dsp(tsk)                                                        \
+do {                                                                   \
+       register u32 *__ts2 __asm__ ("r2") =                            \
+                       (u32 *)&tsk->thread.dsp_status + 14;            \
+                                                                       \
+       __asm__ __volatile__ (                                          \
+               ".balign 4\n\t"                                         \
+               "stc.l  mod, @-r2\n\t"                          \
+               "stc.l  re, @-r2\n\t"                                   \
+               "stc.l  rs, @-r2\n\t"                                   \
+               "sts.l  dsr, @-r2\n\t"                          \
+               "sts.l  y1, @-r2\n\t"                                   \
+               "sts.l  y0, @-r2\n\t"                                   \
+               "sts.l  x1, @-r2\n\t"                                   \
+               "sts.l  x0, @-r2\n\t"                                   \
+               "sts.l  a0, @-r2\n\t"                                   \
+               ".word  0xf653          ! movs.l        a1, @-r2\n\t"   \
+               ".word  0xf6f3          ! movs.l        a0g, @-r2\n\t"  \
+               ".word  0xf6d3          ! movs.l        a1g, @-r2\n\t"  \
+               ".word  0xf6c3          ! movs.l        m0, @-r2\n\t"   \
+               ".word  0xf6e3          ! movs.l        m1, @-r2\n\t"   \
+               : : "r" (__ts2));                                       \
+} while (0)
+
+#else
+
+#define is_dsp_enabled(tsk)    (0)
+#define __save_dsp(tsk)                do { } while (0)
+#define __restore_dsp(tsk)     do { } while (0)
+#endif
+
 struct task_struct *__switch_to(struct task_struct *prev,
                                struct task_struct *next);
 
 /*
  *     switch_to() should switch tasks to task nr n, first
  */
-#define switch_to(prev, next, last)                                    \
-do {                                                                   \
-       register u32 *__ts1 __asm__ ("r1") = (u32 *)&prev->thread.sp;   \
-       register u32 *__ts2 __asm__ ("r2") = (u32 *)&prev->thread.pc;   \
-       register u32 *__ts4 __asm__ ("r4") = (u32 *)prev;               \
-       register u32 *__ts5 __asm__ ("r5") = (u32 *)next;               \
-       register u32 *__ts6 __asm__ ("r6") = (u32 *)&next->thread.sp;   \
-       register u32 __ts7 __asm__ ("r7") = next->thread.pc;            \
-       struct task_struct *__last;                                     \
-                                                                       \
-       __asm__ __volatile__ (                                          \
-               ".balign 4\n\t"                                         \
-               "stc.l  gbr, @-r15\n\t"                                 \
-               "sts.l  pr, @-r15\n\t"                                  \
-               "mov.l  r8, @-r15\n\t"                                  \
-               "mov.l  r9, @-r15\n\t"                                  \
-               "mov.l  r10, @-r15\n\t"                                 \
-               "mov.l  r11, @-r15\n\t"                                 \
-               "mov.l  r12, @-r15\n\t"                                 \
-               "mov.l  r13, @-r15\n\t"                                 \
-               "mov.l  r14, @-r15\n\t"                                 \
-               "mov.l  r15, @r1\t! save SP\n\t"                        \
-               "mov.l  @r6, r15\t! change to new stack\n\t"            \
-               "mova   1f, %0\n\t"                                     \
-               "mov.l  %0, @r2\t! save PC\n\t"                         \
-               "mov.l  2f, %0\n\t"                                     \
-               "jmp    @%0\t! call __switch_to\n\t"                    \
-               " lds   r7, pr\t!  with return to new PC\n\t"           \
-               ".balign        4\n"                                    \
-               "2:\n\t"                                                \
-               ".long  __switch_to\n"                                  \
-               "1:\n\t"                                                \
-               "mov.l  @r15+, r14\n\t"                                 \
-               "mov.l  @r15+, r13\n\t"                                 \
-               "mov.l  @r15+, r12\n\t"                                 \
-               "mov.l  @r15+, r11\n\t"                                 \
-               "mov.l  @r15+, r10\n\t"                                 \
-               "mov.l  @r15+, r9\n\t"                                  \
-               "mov.l  @r15+, r8\n\t"                                  \
-               "lds.l  @r15+, pr\n\t"                                  \
-               "ldc.l  @r15+, gbr\n\t"                                 \
-               : "=z" (__last)                                         \
-               : "r" (__ts1), "r" (__ts2), "r" (__ts4),                \
-                 "r" (__ts5), "r" (__ts6), "r" (__ts7)                 \
-               : "r3", "t");                                           \
-                                                                       \
-       last = __last;                                                  \
+#define switch_to(prev, next, last)                            \
+do {                                                           \
+       register u32 *__ts1 __asm__ ("r1");                     \
+       register u32 *__ts2 __asm__ ("r2");                     \
+       register u32 *__ts4 __asm__ ("r4");                     \
+       register u32 *__ts5 __asm__ ("r5");                     \
+       register u32 *__ts6 __asm__ ("r6");                     \
+       register u32 __ts7 __asm__ ("r7");                      \
+       struct task_struct *__last;                             \
+                                                               \
+       if (is_dsp_enabled(prev))                               \
+               __save_dsp(prev);                               \
+                                                               \
+       __ts1 = (u32 *)&prev->thread.sp;                        \
+       __ts2 = (u32 *)&prev->thread.pc;                        \
+       __ts4 = (u32 *)prev;                                    \
+       __ts5 = (u32 *)next;                                    \
+       __ts6 = (u32 *)&next->thread.sp;                        \
+       __ts7 = next->thread.pc;                                \
+                                                               \
+       __asm__ __volatile__ (                                  \
+               ".balign 4\n\t"                                 \
+               "stc.l  gbr, @-r15\n\t"                         \
+               "sts.l  pr, @-r15\n\t"                          \
+               "mov.l  r8, @-r15\n\t"                          \
+               "mov.l  r9, @-r15\n\t"                          \
+               "mov.l  r10, @-r15\n\t"                         \
+               "mov.l  r11, @-r15\n\t"                         \
+               "mov.l  r12, @-r15\n\t"                         \
+               "mov.l  r13, @-r15\n\t"                         \
+               "mov.l  r14, @-r15\n\t"                         \
+               "mov.l  r15, @r1\t! save SP\n\t"                \
+               "mov.l  @r6, r15\t! change to new stack\n\t"    \
+               "mova   1f, %0\n\t"                             \
+               "mov.l  %0, @r2\t! save PC\n\t"                 \
+               "mov.l  2f, %0\n\t"                             \
+               "jmp    @%0\t! call __switch_to\n\t"            \
+               " lds   r7, pr\t!  with return to new PC\n\t"   \
+               ".balign        4\n"                            \
+               "2:\n\t"                                        \
+               ".long  __switch_to\n"                          \
+               "1:\n\t"                                        \
+               "mov.l  @r15+, r14\n\t"                         \
+               "mov.l  @r15+, r13\n\t"                         \
+               "mov.l  @r15+, r12\n\t"                         \
+               "mov.l  @r15+, r11\n\t"                         \
+               "mov.l  @r15+, r10\n\t"                         \
+               "mov.l  @r15+, r9\n\t"                          \
+               "mov.l  @r15+, r8\n\t"                          \
+               "lds.l  @r15+, pr\n\t"                          \
+               "ldc.l  @r15+, gbr\n\t"                         \
+               : "=z" (__last)                                 \
+               : "r" (__ts1), "r" (__ts2), "r" (__ts4),        \
+                 "r" (__ts5), "r" (__ts6), "r" (__ts7)         \
+               : "r3", "t");                                   \
+                                                               \
+       last = __last;                                          \
+} while (0)
+
+#define finish_arch_switch(prev)                               \
+do {                                                           \
+       if (is_dsp_enabled(prev))                               \
+               __restore_dsp(prev);                            \
 } while (0)
 
 #define __uses_jump_to_uncached \

diff --git a/arch/sh/kernel/cpu/sh3/entry.S b/arch/sh/kernel/cpu/sh3/entry.S
index 55da0ff9848db392297c05d12773452c74bf1793..3cb531f233f24cd27edcf1f8aedd7d86201c0d5c 100644 (file)
--- a/arch/sh/kernel/cpu/sh3/entry.S
+++ b/arch/sh/kernel/cpu/sh3/entry.S
@@ -254,40 +254,6 @@ restore_all:
 
        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 @@ general_exception:
        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 @@ general_exception:
 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 @@ prepare_stack_save_dsp:
        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 @@ handle_exception:
        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 @@ ENTRY(handle_interrupt)
        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 ddafbbbab2abe041dbdca39aa000dc4637f21137..0747fabd73a7d117e8d3bbdd942ec20f2147b910 100644 (file)
--- a/arch/sh/kernel/process_32.c
+++ b/arch/sh/kernel/process_32.c
@@ -176,14 +176,26 @@ int copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
 {
        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 29ca09d24ef855b54c5e6bd431a01fd83e96cd0b..f7b22dd83b0c125ada90571539eda06530d04613 100644 (file)
--- a/arch/sh/kernel/ptrace_32.c
+++ b/arch/sh/kernel/ptrace_32.c
@@ -200,7 +200,8 @@ static int dspregs_get(struct task_struct *target,
                       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 @@ static int dspregs_set(struct task_struct *target,
                       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 60dcf87ed019b76b5be51baf24c2156122b04350..30ca9c51e52db677ac1f2d0cf0b5da287a78c466 100644 (file)
--- a/arch/sh/kernel/traps_32.c
+++ b/arch/sh/kernel/traps_32.c
@@ -664,6 +664,8 @@ asmlinkage void do_reserved_inst(unsigned long r4, unsigned long r5,
        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