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

Richard Kuo
2011-09-09T01:11:27Z

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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;
+}