Hexagon: Add ptrace support

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>

diff --git a/arch/hexagon/include/asm/ptrace.h b/arch/hexagon/include/asm/ptrace.h
new file mode 100644 (file)
index 0000000..5cfb1b9
--- /dev/null
+++ b/arch/hexagon/include/asm/ptrace.h
@@ -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

diff --git a/arch/hexagon/kernel/ptrace.c b/arch/hexagon/kernel/ptrace.c
new file mode 100644 (file)
index 0000000..3623c08
--- /dev/null
+++ b/arch/hexagon/kernel/ptrace.c
@@ -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;
+}