[PATCH V2] score: add regset support

[PATCH V2] score: add regset support

[liqin.chen]

ptrace.c add register sets support for score architecture.

- genregs_get(struct task_struct *target,
           const struct user_regset *regset,
           unsigned int pos, unsigned int count,
           void *kbuf, void __user *ubuf)
    Retrieve the contents of score userspace general registers.

- genregs_set(struct task_struct *target,
           const struct user_regset *regset,
           unsigned int pos, unsigned int count,
           const void *kbuf, const void __user *ubuf)
    Update the contents of the score userspace general registers.

Signed-off-by: Chen Liqin <liqin.chen@sunplusct.com>
---
 arch/score/include/asm/elf.h    |   18 +++--
 arch/score/include/asm/ptrace.h |    2 +
 arch/score/kernel/ptrace.c      |  140 
++++++++++++++++++++++++++++++--------
 3 files changed, 123 insertions(+), 37 deletions(-)

diff --git a/arch/score/include/asm/elf.h b/arch/score/include/asm/elf.h
index 8324363..43526d9 100644
--- a/arch/score/include/asm/elf.h
+++ b/arch/score/include/asm/elf.h
@@ -1,9 +1,8 @@
 #ifndef _ASM_SCORE_ELF_H
 #define _ASM_SCORE_ELF_H
 
-/* ELF register definitions */
-#define ELF_NGREG    45
-#define ELF_NFPREG    33
+#include <linux/ptrace.h>
+
 #define EM_SCORE7    135
 
 /* Relocation types. */
@@ -30,11 +29,15 @@
 #define R_SCORE_IMM30        20
 #define R_SCORE_IMM32        21
 
-typedef unsigned long elf_greg_t;
-typedef elf_greg_t elf_gregset_t[ELF_NGREG];
+/* ELF register definitions */
+typedef unsigned long    elf_greg_t;
+
+#define ELF_NGREG    (sizeof(struct pt_regs) / sizeof(elf_greg_t))
+typedef elf_greg_t    elf_gregset_t[ELF_NGREG];
 
-typedef double elf_fpreg_t;
-typedef elf_fpreg_t elf_fpregset_t[ELF_NFPREG];
+/* Score does not have fp regs. */
+typedef double        elf_fpreg_t;
+typedef elf_fpreg_t    elf_fpregset_t;
 
 #define elf_check_arch(x)    ((x)->e_machine == EM_SCORE7)
 
@@ -57,6 +60,7 @@ do {                                \
 struct task_struct;
 struct pt_regs;
 
+#define CORE_DUMP_USE_REGSET
 #define USE_ELF_CORE_DUMP
 #define ELF_EXEC_PAGESIZE    PAGE_SIZE
 
diff --git a/arch/score/include/asm/ptrace.h 
b/arch/score/include/asm/ptrace.h
index 66b14c8..19ce850 100644
--- a/arch/score/include/asm/ptrace.h
+++ b/arch/score/include/asm/ptrace.h
@@ -74,6 +74,8 @@ struct pt_regs {
 
 #ifdef __KERNEL__
 
+struct task_struct;
+
 /*
  * Does the process account for user or for system time?
  */
diff --git a/arch/score/kernel/ptrace.c b/arch/score/kernel/ptrace.c
index 1db876b..43784d8 100644
--- a/arch/score/kernel/ptrace.c
+++ b/arch/score/kernel/ptrace.c
@@ -23,11 +23,113 @@
  * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  */
 
+#include <linux/elf.h>
 #include <linux/kernel.h>
 #include <linux/ptrace.h>
+#include <linux/regset.h>
 
 #include <asm/uaccess.h>
 
+/*
+ * retrieve the contents of SCORE userspace general registers
+ */
+static int genregs_get(struct task_struct *target,
+               const struct user_regset *regset,
+               unsigned int pos, unsigned int count,
+               void *kbuf, void __user *ubuf)
+{
+    const struct pt_regs *regs = task_pt_regs(target);
+    int ret;
+
+    /* skip 8 * sizeof(unsigned long) not use for pt_regs */
+    ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
+                    0, offsetof(struct pt_regs, regs));
+
+    /* r0 - r31 */
+    ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
+                  regs->regs,
+                  offsetof(struct pt_regs, regs),
+                  offsetof(struct pt_regs, cel));
+
+    if (!ret)
+        /* cel, ceh, sr0, sr1, sr2, epc, ema, psr, ecr, condition */
+        ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
+                    &regs->cel,
+                    offsetof(struct pt_regs, cel),
+                    offsetof(struct pt_regs, is_syscall));
+
+    if (!ret)
+        ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
+                        sizeof(struct pt_regs), -1);
+
+    return ret;
+}
+
+/*
+ * update the contents of the SCORE userspace general registers
+ */
+static int genregs_set(struct task_struct *target,
+               const struct user_regset *regset,
+               unsigned int pos, unsigned int count,
+               const void *kbuf, const void __user *ubuf)
+{
+    struct pt_regs *regs = task_pt_regs(target);
+    int ret;
+
+    /* skip 8 * sizeof(unsigned long) */
+    ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
+                    0, offsetof(struct pt_regs, regs));
+
+    /* r0 - r31 */
+    ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
+                  regs->regs,
+                  offsetof(struct pt_regs, regs),
+                  offsetof(struct pt_regs, cel));
+
+    if (!ret)
+        /* cel, ceh, sr0, sr1, sr2, epc, ema, psr, ecr, condition */
+        ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
+                    &regs->cel,
+                    offsetof(struct pt_regs, cel),
+                    offsetof(struct pt_regs, is_syscall));
+
+    if (!ret)
+        ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
+                        sizeof(struct pt_regs), -1);
+
+    return ret;
+}
+
+/*
+ * Define the register sets available on the score7 under Linux
+ */
+enum score7_regset {
+    REGSET_GENERAL,
+};
+
+static const struct user_regset score7_regsets[] = {
+    [REGSET_GENERAL] = {
+        .core_note_type    = NT_PRSTATUS,
+        .n        = ELF_NGREG,
+        .size        = sizeof(long),
+        .align        = sizeof(long),
+        .get        = genregs_get,
+        .set        = genregs_set,
+    },
+};
+
+static const struct user_regset_view user_score_native_view = {
+    .name        = "score7",
+    .e_machine    = EM_SCORE7,
+    .regsets    = score7_regsets,
+    .n        = ARRAY_SIZE(score7_regsets),
+};
+
+const struct user_regset_view *task_user_regset_view(struct task_struct 
*task)
+{
+    return &user_score_native_view;
+}
+
 static int is_16bitinsn(unsigned long insn)
 {
     if ((insn & INSN32_MASK) == INSN32_MASK)
@@ -80,34 +182,6 @@ write_tsk_long(struct task_struct *child,
     return copied != sizeof(val) ? -EIO : 0;
 }
 
-/*
- * Get all user integer registers.
- */
-static int ptrace_getregs(struct task_struct *tsk, void __user *uregs)
-{
-    struct pt_regs *regs = task_pt_regs(tsk);
-
-    return copy_to_user(uregs, regs, sizeof(struct pt_regs)) ? -EFAULT : 0;
-}
-
-/*
- * Set all user integer registers.
- */
-static int ptrace_setregs(struct task_struct *tsk, void __user *uregs)
-{
-    struct pt_regs newregs;
-    int ret;
-
-    ret = -EFAULT;
-    if (copy_from_user(&newregs, uregs, sizeof(struct pt_regs)) == 0) {
-        struct pt_regs *regs = task_pt_regs(tsk);
-        *regs = newregs;
-        ret = 0;
-    }
-
-    return ret;
-}
-
 void user_enable_single_step(struct task_struct *child)
 {
     /* far_epc is the target of branch */
@@ -356,11 +430,17 @@ arch_ptrace(struct task_struct *child, long 
request, long addr, long data)
     }
 
     case PTRACE_GETREGS:
-        ret = ptrace_getregs(child, (void __user *)datap);
+        return copy_regset_to_user(child, &user_score_native_view,
+                        REGSET_GENERAL,
+                        0, sizeof(struct pt_regs),
+                        (void __user *)datap);
         break;
 
     case PTRACE_SETREGS:
-        ret = ptrace_setregs(child, (void __user *)datap);
+        return copy_regset_from_user(child, &user_score_native_view,
+                        REGSET_GENERAL,
+                        0, sizeof(struct pt_regs),
+                        (const void __user *)datap);
         break;
 
     default:
-- 
1.6.2

Re: [PATCH V2] score: add regset support

[Arnd Bergmann]

On Friday 10 July 2009, liqin.chen wrote:
> +static int genregs_get(struct task_struct *target,
> +               const struct user_regset *regset,
> +               unsigned int pos, unsigned int count,
> +               void *kbuf, void __user *ubuf)
> +{
> +    const struct pt_regs *regs = task_pt_regs(target);
> +    int ret;
> +
> +    /* skip 8 * sizeof(unsigned long) not use for pt_regs */
> +    ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
> +                    0, offsetof(struct pt_regs, regs));
> +
> +    /* r0 - r31 */
> +    ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
> +                  regs->regs,
> +                  offsetof(struct pt_regs, regs),
> +                  offsetof(struct pt_regs, cel));
> +
> +    if (!ret)
> +        /* cel, ceh, sr0, sr1, sr2, epc, ema, psr, ecr, condition */
> +        ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
> +                    &regs->cel,
> +                    offsetof(struct pt_regs, cel),
> +                    offsetof(struct pt_regs, is_syscall));

The two user_regset_copyout are consecutive, so AFAICT they can
be combined into a single function call.

> +
> +    if (!ret)
> +        ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
> +                        sizeof(struct pt_regs), -1);
> +
> +    return ret;
> +}

While the code looks correct to me now based on Rolands comments,
I think it would be nicer to define separate pt_regs and user_regset
data structures to make the two independent and give you more
flexibility with the kernel stack layout in the future.

Maybe you could change

struct pt_regs {
       unsigned long pad0[6];
       unsigned long orig_r4;
       unsigned long orig_r7;
       unsigned long regs[32];

       unsigned long cel;
       unsigned long ceh;

       unsigned long sr0;      /* cnt */
       unsigned long sr1;      /* lcr */
       unsigned long sr2;      /* scr */

       unsigned long cp0_epc;
       unsigned long cp0_ema;
       unsigned long cp0_psr;
       unsigned long cp0_ecr;
       unsigned long cp0_condition;

       long is_syscall;
};

to

struct pt_regs {
       unsigned long regs[32];

       unsigned long cel;
       unsigned long ceh;

       unsigned long sr0;      /* cnt */
       unsigned long sr1;      /* lcr */
       unsigned long sr2;      /* scr */

       unsigned long cp0_epc;
       unsigned long cp0_ema;
       unsigned long cp0_psr;
       unsigned long cp0_ecr;
       unsigned long cp0_condition;
#ifdef __KERNEL__
       unsigned long orig_r4;
       unsigned long orig_r7;
       long is_syscall;
       unsigned long pad0[3];
#else
       unsigned long pad0[6];
#endif
};

> @@ -356,11 +430,17 @@ arch_ptrace(struct task_struct *child, long 
> request, long addr, long data)
>      }
>  
>      case PTRACE_GETREGS:
> -        ret = ptrace_getregs(child, (void __user *)datap);
> +        return copy_regset_to_user(child, &user_score_native_view,
> +                        REGSET_GENERAL,
> +                        0, sizeof(struct pt_regs),
> +                        (void __user *)datap);                        	
>          break;
>  
>      case PTRACE_SETREGS:
> -        ret = ptrace_setregs(child, (void __user *)datap);
> +        return copy_regset_from_user(child, &user_score_native_view,
> +                        REGSET_GENERAL,
> +                        0, sizeof(struct pt_regs),
> +                        (const void __user *)datap);
>          break;
>  
>      default:

I guess you still need to remove the PTRACE_PEEKUSR and PTRACE_POKEUSR
code, as mentioned by Roland.

Roland, Christoph: Do you think it would be reasonable to implement
this in common code? That would make it possible to have an empty
arch_ptrace() function.

diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index 61c78b2..a6b7862 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -570,6 +570,21 @@ int ptrace_request(struct task_struct *child, long request,
 			return 0;
 		return ptrace_resume(child, request, SIGKILL);
 
+#if defined(PTRACE_GENERIC_GETREGS) && defined(REGSET_GENERAL)
+	case PTRACE_GETREGS:
+		return copy_regset_to_user(child,
+				task_user_regset_view(child),
+				REGSET_GENERAL, 0,
+				sizeof(struct pt_regs),
+				(void __user *)datap);
+	case PTRACE_GETREGS:
+		return copy_regset_from_user(child,
+				task_user_regset_view(child),
+				REGSET_GENERAL, 0,
+				sizeof(struct pt_regs),
+				(void __user *)datap);
+#endif
+
 	default:
 		break;
 	}

Re: [PATCH V2] score: add regset support

[liqin.chen]

linux-arch-owner@vger.kernel.org 写于 2009-07-10 20:49:44:

> struct pt_regs {
>        unsigned long pad0[6];
>        unsigned long orig_r4;
>        unsigned long orig_r7;
>        unsigned long regs[32];
> 
>        unsigned long cel;
>        unsigned long ceh;
> 
>        unsigned long sr0;      /* cnt */
>        unsigned long sr1;      /* lcr */
>        unsigned long sr2;      /* scr */
> 
>        unsigned long cp0_epc;
>        unsigned long cp0_ema;
>        unsigned long cp0_psr;
>        unsigned long cp0_ecr;
>        unsigned long cp0_condition;
> 
>        long is_syscall;
> };
> 
> to
> 
> struct pt_regs {
>        unsigned long regs[32];
> 
>        unsigned long cel;
>        unsigned long ceh;
> 
>        unsigned long sr0;      /* cnt */
>        unsigned long sr1;      /* lcr */
>        unsigned long sr2;      /* scr */
> 
>        unsigned long cp0_epc;
>        unsigned long cp0_ema;
>        unsigned long cp0_psr;
>        unsigned long cp0_ecr;
>        unsigned long cp0_condition;
> #ifdef __KERNEL__
>        unsigned long orig_r4;
>        unsigned long orig_r7;
>        long is_syscall;
>        unsigned long pad0[3];
> #else
>        unsigned long pad0[6];
> #endif
> };
> 

unsigned long pad0[6];

was place at the start of pt_regs use 
to hold the arguments from userland.
caller(exception handler) not need to
change stack pointer.

unsigned long orig_r4;
unsigned long orig_r7;
move to end of the pt_regs haven't 
problem.

Thanks,
Liqin

Re: [PATCH V2] score: add regset support

[Arnd Bergmann]

On Monday 13 July 2009, liqin.chen@sunplusct.com wrote:
> 
> unsigned long pad0[6];
> 
> was place at the start of pt_regs use 
> to hold the arguments from userland.
> caller(exception handler) not need to
> change stack pointer.
>
> unsigned long orig_r4;
> unsigned long orig_r7;
> move to end of the pt_regs haven't 
> problem.

Ok, I see.

Maybe to get a nicer layout, you can define separate
structures then:

struct user_regs_struct {
        unsigned long regs[32];

        unsigned long cel;
        unsigned long ceh;
 
        unsigned long sr0;      /* cnt */
        unsigned long sr1;      /* lcr */
        unsigned long sr2;      /* scr */
 
        unsigned long cp0_epc;
        unsigned long cp0_ema;
        unsigned long cp0_psr;
        unsigned long cp0_ecr;
        unsigned long cp0_condition;

	unsigned long reserved[6]; /* future extensions */
};

#ifdef __KERNEL__
struct pt_regs {
	/* stack arguments */
        unsigned long pad0[6];

	/* internal use */
        unsigned long orig_r4;
        unsigned long orig_r7;
        long is_syscall;

	/* saved registers */
	struct user_regs_struct uregs;
};
#endif

That would keep the user struct relatively clean.

	Arnd <><

Re: [PATCH V2] score: add regset support

[liqin.chen]

Arnd Bergmann <arnd@arndb.de> 写于 2009-07-13 22:24:28:

> Maybe to get a nicer layout, you can define separate
> structures then:
> 
> struct user_regs_struct {
>         unsigned long regs[32];
> 
>         unsigned long cel;
>         unsigned long ceh;
> 
>         unsigned long sr0;      /* cnt */
>         unsigned long sr1;      /* lcr */
>         unsigned long sr2;      /* scr */
> 
>         unsigned long cp0_epc;
>         unsigned long cp0_ema;
>         unsigned long cp0_psr;
>         unsigned long cp0_ecr;
>         unsigned long cp0_condition;
> 
>    unsigned long reserved[6]; /* future extensions */
> };
> 
> #ifdef __KERNEL__
> struct pt_regs {
>    /* stack arguments */
>         unsigned long pad0[6];
> 
>    /* internal use */
>         unsigned long orig_r4;
>         unsigned long orig_r7;
>         long is_syscall;
> 
>    /* saved registers */
>    struct user_regs_struct uregs;
> };
> #endif
> 
> That would keep the user struct relatively clean.

OK, I will send this patch soon.

Thanks,
liqin

Re: [PATCH V2] score: add regset support

[Roland McGrath]

IMHO it is certainly a wise choice to have some struct (be it called
user_regs_struct or whatever) that describes the exact userland layout.
(I think it's also fine to just call that elf_gregset_t and have it be an
array, with REG_* defines/enum somewhere to document its indices.  It's
just a matter of taste for the arch folks.)

Given such a struct, the regset code can refer to it (with offsetof, e.g.)
and that will make it far easier to read, understand, and review.


Thanks,
Roland