[SPARC32]: Add user regset support.

It is missing lazy FPU handling for the current task,
but that can be added later.
Signed-off-by: David S. Miller <davem@davemloft.net>

arch/sparc/kernel/ptrace.c

 /* ptrace.c: Sparc process tracing support.
  *
- * Copyright (C) 1996 David S. Miller (davem@caipfs.rutgers.edu)
+ * Copyright (C) 1996, 2008 David S. Miller (davem@davemloft.net)
  *
  * Based upon code written by Ross Biro, Linus Torvalds, Bob Manson,
  * and David Mosberger.
@@ -19,6 +19,8 @@
 #include <linux/smp_lock.h>
 #include <linux/security.h>
 #include <linux/signal.h>
+#include <linux/regset.h>
+#include <linux/elf.h>
 
 #include <asm/pgtable.h>
 #include <asm/system.h>
@@ -258,6 +260,287 @@ void ptrace_disable(struct task_struct *child)
 	/* nothing to do */
 }
 
+enum sparc_regset {
+	REGSET_GENERAL,
+	REGSET_FP,
+};
+
+static int genregs32_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 = target->thread.kregs;
+	unsigned long __user *reg_window;
+	unsigned long *k = kbuf;
+	unsigned long __user *u = ubuf;
+	unsigned long reg;
+
+	if (target == current)
+		flush_user_windows();
+
+	pos /= sizeof(reg);
+	count /= sizeof(reg);
+
+	if (kbuf) {
+		for (; count > 0 && pos < 16; count--)
+			*k++ = regs->u_regs[pos++];
+
+		reg_window = (unsigned long __user *) regs->u_regs[UREG_I6];
+		for (; count > 0 && pos < 32; count--) {
+			if (get_user(*k++, &reg_window[pos++]))
+				return -EFAULT;
+		}
+	} else {
+		for (; count > 0 && pos < 16; count--) {
+			if (put_user(regs->u_regs[pos++], u++))
+				return -EFAULT;
+		}
+
+		reg_window = (unsigned long __user *) regs->u_regs[UREG_I6];
+		for (; count > 0 && pos < 32; count--) {
+			if (get_user(reg, &reg_window[pos++]) ||
+			    put_user(reg, u++))
+				return -EFAULT;
+		}
+	}
+	while (count > 0) {
+		switch (pos) {
+		case 32: /* PSR */
+			reg = regs->psr;
+			break;
+		case 33: /* PC */
+			reg = regs->pc;
+			break;
+		case 34: /* NPC */
+			reg = regs->npc;
+			break;
+		case 35: /* Y */
+			reg = regs->y;
+			break;
+		case 36: /* WIM */
+		case 37: /* TBR */
+			reg = 0;
+			break;
+		default:
+			goto finish;
+		}
+
+		if (kbuf)
+			*k++ = reg;
+		else if (put_user(reg, u++))
+			return -EFAULT;
+		pos++;
+		count--;
+	}
+finish:
+	pos *= sizeof(reg);
+	count *= sizeof(reg);
+
+	return user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
+					38 * sizeof(reg), -1);
+}
+
+static int genregs32_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 = target->thread.kregs;
+	unsigned long __user *reg_window;
+	const unsigned long *k = kbuf;
+	const unsigned long __user *u = ubuf;
+	unsigned long reg;
+
+	if (target == current)
+		flush_user_windows();
+
+	pos /= sizeof(reg);
+	count /= sizeof(reg);
+
+	if (kbuf) {
+		for (; count > 0 && pos < 16; count--)
+			regs->u_regs[pos++] = *k++;
+
+		reg_window = (unsigned long __user *) regs->u_regs[UREG_I6];
+		for (; count > 0 && pos < 32; count--) {
+			if (put_user(*k++, &reg_window[pos++]))
+				return -EFAULT;
+		}
+	} else {
+		for (; count > 0 && pos < 16; count--) {
+			if (get_user(reg, u++))
+				return -EFAULT;
+			regs->u_regs[pos++] = reg;
+		}
+
+		reg_window = (unsigned long __user *) regs->u_regs[UREG_I6];
+		for (; count > 0 && pos < 32; count--) {
+			if (get_user(reg, u++) ||
+			    put_user(reg, &reg_window[pos++]))
+				return -EFAULT;
+		}
+	}
+	while (count > 0) {
+		unsigned long psr;
+
+		if (kbuf)
+			reg = *k++;
+		else if (get_user(reg, u++))
+			return -EFAULT;
+
+		switch (pos) {
+		case 32: /* PSR */
+			psr = regs->psr;
+			psr &= ~PSR_ICC;
+			psr |= (reg & PSR_ICC);
+			regs->psr = psr;
+			break;
+		case 33: /* PC */
+			regs->pc = reg;
+			break;
+		case 34: /* NPC */
+			regs->npc = reg;
+			break;
+		case 35: /* Y */
+			regs->y = reg;
+			break;
+		case 36: /* WIM */
+		case 37: /* TBR */
+			break;
+		default:
+			goto finish;
+		}
+
+		pos++;
+		count--;
+	}
+finish:
+	pos *= sizeof(reg);
+	count *= sizeof(reg);
+
+	return user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
+					 38 * sizeof(reg), -1);
+}
+
+static int fpregs32_get(struct task_struct *target,
+			const struct user_regset *regset,
+			unsigned int pos, unsigned int count,
+			void *kbuf, void __user *ubuf)
+{
+	const unsigned long *fpregs = target->thread.float_regs;
+	int ret = 0;
+
+#if 0
+	if (target == current)
+		save_and_clear_fpu();
+#endif
+
+	ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
+				  fpregs,
+				  0, 32 * sizeof(u32));
+
+	if (!ret)
+		ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
+					       32 * sizeof(u32),
+					       33 * sizeof(u32));
+	if (!ret)
+		ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
+					  &target->thread.fsr,
+					  33 * sizeof(u32),
+					  34 * sizeof(u32));
+
+	if (!ret) {
+		unsigned long val;
+
+		val = (1 << 8) | (8 << 16);
+		ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
+					  &val,
+					  34 * sizeof(u32),
+					  35 * sizeof(u32));
+	}
+
+	if (!ret)
+		ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
+					       35 * sizeof(u32), -1);
+
+	return ret;
+}
+
+static int fpregs32_set(struct task_struct *target,
+			const struct user_regset *regset,
+			unsigned int pos, unsigned int count,
+			const void *kbuf, const void __user *ubuf)
+{
+	unsigned long *fpregs = target->thread.float_regs;
+	int ret;
+
+#if 0
+	if (target == current)
+		save_and_clear_fpu();
+#endif
+	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
+				 fpregs,
+				 0, 32 * sizeof(u32));
+	if (!ret)
+		user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
+					  32 * sizeof(u32),
+					  33 * sizeof(u32));
+	if (!ret && count > 0) {
+		ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
+					 &target->thread.fsr,
+					 33 * sizeof(u32),
+					 34 * sizeof(u32));
+	}
+
+	if (!ret)
+		ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
+						34 * sizeof(u32), -1);
+	return ret;
+}
+
+static const struct user_regset sparc32_regsets[] = {
+	/* Format is:
+	 * 	G0 --> G7
+	 *	O0 --> O7
+	 *	L0 --> L7
+	 *	I0 --> I7
+	 *	PSR, PC, nPC, Y, WIM, TBR
+	 */
+	[REGSET_GENERAL] = {
+		.core_note_type = NT_PRSTATUS,
+		.n = 38 * sizeof(u32),
+		.size = sizeof(u32), .align = sizeof(u32),
+		.get = genregs32_get, .set = genregs32_set
+	},
+	/* Format is:
+	 *	F0 --> F31
+	 *	empty 32-bit word
+	 *	FSR (32--bit word)
+	 *	FPU QUEUE COUNT (8-bit char)
+	 *	FPU QUEUE ENTRYSIZE (8-bit char)
+	 *	FPU ENABLED (8-bit char)
+	 *	empty 8-bit char
+	 *	FPU QUEUE (64 32-bit ints)
+	 */
+	[REGSET_FP] = {
+		.core_note_type = NT_PRFPREG,
+		.n = 99 * sizeof(u32),
+		.size = sizeof(u32), .align = sizeof(u32),
+		.get = fpregs32_get, .set = fpregs32_set
+	},
+};
+
+static const struct user_regset_view user_sparc32_view = {
+	.name = "sparc", .e_machine = EM_SPARC,
+	.regsets = sparc32_regsets, .n = ARRAY_SIZE(sparc32_regsets)
+};
+
+const struct user_regset_view *task_user_regset_view(struct task_struct *task)
+{
+	return &user_sparc32_view;
+}
+
 asmlinkage void do_ptrace(struct pt_regs *regs)
 {
 	unsigned long request = regs->u_regs[UREG_I0];