[patch v3 19/36] Hexagon: Add ptrace support

[Richard Kuo <rkuo@codeaurora.org>]

[-- Attachment #1: ptrace.diff --]
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Will look at the more generic ptrace support in the future.

Signed-off-by: Richard Kuo <rkuo@codeaurora.org>
Signed-off-by: Linas Vepstas <linas@codeaurora.org>

---
 arch/hexagon/include/asm/ptrace.h |   46 +++++
 arch/hexagon/kernel/ptrace.c      |  333 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 379 insertions(+)

Index: linux-hexagon-kernel/arch/hexagon/include/asm/ptrace.h
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ linux-hexagon-kernel/arch/hexagon/include/asm/ptrace.h	2011-09-03 20:14:59.684981279 -0500
@@ -0,0 +1,46 @@
+/*
+ * Ptrace definitions for the Hexagon architecture
+ *
+ * Copyright (c) 2010-2011, Code Aurora Forum. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+#ifndef _ASM_PTRACE_H
+#define _ASM_PTRACE_H
+
+#include <asm/registers.h>
+
+/*  arch_ptrace and ptrace_disable use task_struct in arg lists  */
+struct task_struct;
+
+/*
+ * ptrace commands not part of Linux base set (but common to essentially
+ * all supported architectures).
+ */
+
+#define PTRACE_GETREGS	12
+#define PTRACE_SETREGS	13
+
+#define N_PTRACE_REGS	44
+
+#define profile_pc(regs) instruction_pointer(regs)
+#define instruction_pointer(regs) pt_elr(regs)
+
+/* kprobe-based event tracer support */
+extern int regs_query_register_offset(const char *name);
+extern const char *regs_query_register_name(unsigned int offset);
+
+#endif
Index: linux-hexagon-kernel/arch/hexagon/kernel/ptrace.c
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ linux-hexagon-kernel/arch/hexagon/kernel/ptrace.c	2011-09-07 13:00:31.110647061 -0500
@@ -0,0 +1,333 @@
+/*
+ * Ptrace support for Hexagon
+ *
+ * Copyright (c) 2010-2011, Code Aurora Forum. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+#include <generated/compile.h>
+
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/mm.h>
+#include <linux/smp.h>
+#include <linux/errno.h>
+#include <linux/ptrace.h>
+#include <linux/regset.h>
+#include <linux/user.h>
+
+#include <asm/system.h>
+#include <asm/user.h>
+
+struct pt_regs_offset {
+	const char *name;
+	int offset;
+};
+
+#define REG_OFFSET_NAME(r) {.name = #r, .offset = offsetof(struct pt_regs, r)}
+#define REG_OFFSET_HVM_NAME(r, s) {.name = #r, \
+				  .offset = offsetof(struct pt_regs, s)}
+#define REG_OFFSET_END {.name = NULL, .offset = 0}
+
+static const struct pt_regs_offset regoffset_table[] = {
+	REG_OFFSET_NAME(r00),
+	REG_OFFSET_NAME(r01),
+	REG_OFFSET_NAME(r02),
+	REG_OFFSET_NAME(r03),
+	REG_OFFSET_NAME(r04),
+	REG_OFFSET_NAME(r05),
+	REG_OFFSET_NAME(r06),
+	REG_OFFSET_NAME(r07),
+	REG_OFFSET_NAME(r08),
+	REG_OFFSET_NAME(r09),
+
+	REG_OFFSET_NAME(r10),
+	REG_OFFSET_NAME(r11),
+	REG_OFFSET_NAME(r12),
+	REG_OFFSET_NAME(r13),
+	REG_OFFSET_NAME(r14),
+	REG_OFFSET_NAME(r15),
+	REG_OFFSET_NAME(r16),
+	REG_OFFSET_NAME(r17),
+	REG_OFFSET_NAME(r18),
+	REG_OFFSET_NAME(r19),
+
+	REG_OFFSET_NAME(r20),
+	REG_OFFSET_NAME(r21),
+	REG_OFFSET_NAME(r22),
+	REG_OFFSET_NAME(r23),
+	REG_OFFSET_NAME(r24),
+	REG_OFFSET_NAME(r25),
+	REG_OFFSET_NAME(r26),
+	REG_OFFSET_NAME(r27),
+	REG_OFFSET_NAME(r28),
+	REG_OFFSET_NAME(r29),
+
+	REG_OFFSET_NAME(r30),
+	REG_OFFSET_NAME(r31),
+
+	REG_OFFSET_NAME(gp),
+	REG_OFFSET_NAME(ugp),
+	REG_OFFSET_NAME(sa0),
+	REG_OFFSET_NAME(lc0),
+	REG_OFFSET_NAME(sa1),
+	REG_OFFSET_NAME(lc1),
+	REG_OFFSET_NAME(m0),
+	REG_OFFSET_NAME(m1),
+	REG_OFFSET_NAME(preds),
+	REG_OFFSET_HVM_NAME(pc, hvmer.vmel),
+	REG_OFFSET_HVM_NAME(cause, hvmer.vmest),
+	REG_OFFSET_HVM_NAME(badva, hvmer.vmbadva),
+};
+
+/**
+ * regs_query_register_offset() - query register offset from its name
+ * @name:      the name of a register
+ *
+ * regs_query_register_offset() returns the offset of a register in struct
+ * pt_regs from its name. If the name is invalid, this returns -EINVAL;
+ */
+int regs_query_register_offset(const char *name)
+{
+	const struct pt_regs_offset *roff;
+	for (roff = regoffset_table; roff->name != NULL; roff++)
+		if (!strcmp(roff->name, name))
+			return roff->offset;
+	return -EINVAL;
+}
+
+/**
+ * regs_query_register_name() - query register name from its offset
+ * @offset:    the offset of a register in struct pt_regs.
+ *
+ * regs_query_register_name() returns the name of a register from its
+ * offset in struct pt_regs. If the @offset is invalid, this returns NULL;
+ */
+const char *regs_query_register_name(unsigned int offset)
+{
+	const struct pt_regs_offset *roff;
+	for (roff = regoffset_table; roff->name != NULL; roff++)
+		if (roff->offset == offset)
+			return roff->name;
+	return NULL;
+}
+
+static int gpr_get(struct task_struct *target,
+		   const struct user_regset *regset,
+		   unsigned int pos, unsigned int count,
+		   void *kbuf, void __user *ubuf)
+{
+	int ret;
+	unsigned int dummy;
+	struct pt_regs *regs = task_pt_regs(target);
+
+
+	if (!regs)
+		return -EIO;
+
+	/* The general idea here is that the copyout must happen in
+	 * exactly the same order in which the userspace expects these
+	 * regs. Now, the sequence in userspace does not match the
+	 * sequence in the kernel, so everything past the 32 gprs
+	 * happens one at a time.
+	 */
+	ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
+				  &regs->r00, 0, 32*sizeof(unsigned long));
+
+#define ONEXT(KPT_REG, USR_REG) \
+	if (!ret) \
+		ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, \
+			KPT_REG, offsetof(struct user_regs_struct, USR_REG), \
+			offsetof(struct user_regs_struct, USR_REG) + \
+				 sizeof(unsigned long));
+
+	/* Must be exactly same sequence as struct user_regs_struct */
+	ONEXT(&regs->gp, gp);
+	ONEXT(&regs->ugp, ugp);
+	ONEXT(&regs->sa0, sa0);
+	ONEXT(&regs->lc0, lc0);
+	ONEXT(&regs->sa1, sa1);
+	ONEXT(&regs->lc1, lc1);
+	ONEXT(&regs->m0, m0);
+	ONEXT(&regs->m1, m1);
+	ONEXT(&regs->preds, p3_0);
+	ONEXT(&pt_elr(regs), pc);
+	dummy = pt_cause(regs);
+	ONEXT(&dummy, cause);
+	ONEXT(&pt_badva(regs), badva);
+
+	/* Pad the rest with zeros, if needed */
+	if (!ret)
+		ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
+					sizeof(struct user_regs_struct), -1);
+	return ret;
+}
+
+static int gpr_set(struct task_struct *target,
+		   const struct user_regset *regset,
+		   unsigned int pos, unsigned int count,
+		   const void *kbuf, const void __user *ubuf)
+{
+	int ret;
+	unsigned long bucket;
+	struct pt_regs *regs = task_pt_regs(target);
+
+	if (!regs)
+		return -EIO;
+
+	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
+				 &regs->r00, 0, 32*sizeof(unsigned long));
+
+#define INEXT(KPT_REG, USR_REG) \
+	if (!ret) \
+		ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, \
+			KPT_REG, offsetof(struct user_regs_struct, USR_REG), \
+			offsetof(struct user_regs_struct, USR_REG) + \
+				sizeof(unsigned long));
+
+	/* Must be exactly same sequence as struct user_regs_struct */
+	INEXT(&regs->gp, gp);
+	INEXT(&regs->ugp, ugp);
+	INEXT(&regs->sa0, sa0);
+	INEXT(&regs->lc0, lc0);
+	INEXT(&regs->sa1, sa1);
+	INEXT(&regs->lc1, lc1);
+	INEXT(&regs->m0, m0);
+	INEXT(&regs->m1, m1);
+	INEXT(&regs->preds, p3_0);
+	INEXT(&pt_elr(regs), pc);
+
+	/* CAUSE and BADVA aren't writeable. */
+	INEXT(&bucket, cause);
+	INEXT(&bucket, badva);
+
+	/* Ignore the rest, if needed */
+	if (!ret)
+		ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
+					sizeof(struct user_regs_struct), -1);
+
+	if (ret)
+		return ret;
+
+	/*
+	 * This is special; SP is actually restored by the VM via the
+	 * special event record which is set by the special trap.
+	 */
+	regs->hvmer.vmpsp = regs->r29;
+	return 0;
+}
+
+enum hexagon_regset {
+	REGSET_GPR,
+};
+
+static const struct user_regset hexagon_regsets[] = {
+	[REGSET_GPR] = {
+		.core_note_type = NT_PRSTATUS,
+		.n = N_PTRACE_REGS,
+		.size = sizeof(unsigned long),
+		.align = sizeof(unsigned long),
+		.get = gpr_get,
+		.set = gpr_set
+	},
+};
+
+static const struct user_regset_view hexagon_user_view = {
+	.name = UTS_MACHINE,
+	.e_machine = ELF_ARCH,
+	.ei_osabi = ELF_OSABI,
+	.regsets = hexagon_regsets,
+	.n = ARRAY_SIZE(hexagon_regsets)
+};
+
+static int ptrace_pokeusr(struct task_struct *target, int regnum,
+			  unsigned long data)
+{
+	struct pt_regs *regs = task_pt_regs(target);
+
+	if (!regs || (regnum < 0))
+		return -EIO;
+
+	if (regnum < 32) {
+		unsigned long *p = &regs->r00;
+		*(p+regnum) = data;
+
+		/* Return happens via HVM */
+		if (regnum == 29)
+			regs->hvmer.vmpsp = regs->r29;
+		return 0;
+	}
+
+/*
+ * Todo:  sync up with gdb on register passing numbering.
+ */
+
+#define SETREG(KPT_REG, USR_REG) \
+	case offsetof(struct user_regs_struct, USR_REG)>>2: \
+		KPT_REG = data; \
+		return 0;
+
+	/* Other regs are scattered about */
+	switch (regnum) {
+	SETREG(regs->gp, gp);
+	SETREG(regs->ugp, ugp);
+	SETREG(regs->sa0, sa0);
+	SETREG(regs->lc0, lc0);
+	SETREG(regs->sa1, sa1);
+	SETREG(regs->lc1, lc1);
+	SETREG(regs->m0, m0);
+	SETREG(regs->m1, m1);
+	SETREG(regs->preds, p3_0);
+	SETREG(pt_elr(regs), pc);
+	}
+
+	/* CAUSE and BADVA aren't writeable. */
+	return -EINVAL;
+}
+
+void ptrace_disable(struct task_struct *child)
+{
+	/* Boilerplate - resolves to null inline if no HW single-step */
+	user_disable_single_step(child);
+}
+
+long arch_ptrace(struct task_struct *child, long request,
+		 unsigned long addr, unsigned long data)
+{
+	void __user *udata = (void __user *) data;
+
+	switch (request) {
+	case PTRACE_POKETEXT:	/* write the word at location addr. */
+	case PTRACE_POKEDATA:
+		return generic_ptrace_pokedata(child, addr, data);
+	case PTRACE_POKEUSR:	/* write register specified by addr. */
+		return ptrace_pokeusr(child, addr, data);
+	case PTRACE_GETREGS:
+		return copy_regset_to_user(child, &hexagon_user_view,
+					   REGSET_GPR, 0,
+					   sizeof(struct user_regs_struct),
+					   udata);
+	case PTRACE_SETREGS:
+		return copy_regset_from_user(child, &hexagon_user_view,
+					     REGSET_GPR, 0,
+					     sizeof(struct user_regs_struct),
+					     udata);
+	default:
+		return ptrace_request(child, request, addr, data);
+	}
+
+	return 0;
+}

--

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