[POWERPC] Add user_regset compat support

This extends task_user_regset_view CONFIG_PPC64 with support for the
32-bit view of register state, compatible with what a CONFIG_PPC32
kernel provides.  This will enable generic machine-independent code to
access user-mode threads' registers for debugging and dumping.

Signed-off-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 162 insertions, 0 deletions

diff --git a/arch/powerpc/kernel/ptrace.c b/arch/powerpc/kernel/ptrace.c
index eb00274e84ba..60de9ee3701d 100644
--- a/arch/powerpc/kernel/ptrace.c
+++ b/arch/powerpc/kernel/ptrace.c
@@ -501,8 +501,170 @@ static const struct user_regset_view user_ppc_native_view = {
         .regsets = native_regsets, .n = ARRAY_SIZE(native_regsets)
 };
 
+#ifdef CONFIG_PPC64
+#include <linux/compat.h>
+
+static int gpr32_get(struct task_struct *target,
+                     const struct user_regset *regset,
+                     unsigned int pos, unsigned int count,
+                     void *kbuf, void __user *ubuf)
+{
+        const unsigned long *regs = &target->thread.regs->gpr[0];
+        compat_ulong_t *k = kbuf;
+        compat_ulong_t __user *u = ubuf;
+        compat_ulong_t reg;
+
+        if (target->thread.regs == NULL)
+                return -EIO;
+
+        CHECK_FULL_REGS(target->thread.regs);
+
+        pos /= sizeof(reg);
+        count /= sizeof(reg);
+
+        if (kbuf)
+                for (; count > 0 && pos < PT_MSR; --count)
+                        *k++ = regs[pos++];
+        else
+                for (; count > 0 && pos < PT_MSR; --count)
+                        if (__put_user((compat_ulong_t) regs[pos++], u++))
+                                return -EFAULT;
+
+        if (count > 0 && pos == PT_MSR) {
+                reg = get_user_msr(target);
+                if (kbuf)
+                        *k++ = reg;
+                else if (__put_user(reg, u++))
+                        return -EFAULT;
+                ++pos;
+                --count;
+        }
+
+        if (kbuf)
+                for (; count > 0 && pos < PT_REGS_COUNT; --count)
+                        *k++ = regs[pos++];
+        else
+                for (; count > 0 && pos < PT_REGS_COUNT; --count)
+                        if (__put_user((compat_ulong_t) regs[pos++], u++))
+                                return -EFAULT;
+
+        kbuf = k;
+        ubuf = u;
+        pos *= sizeof(reg);
+        count *= sizeof(reg);
+        return user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
+                                        PT_REGS_COUNT * sizeof(reg), -1);
+}
+
+static int gpr32_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 *regs = &target->thread.regs->gpr[0];
+        const compat_ulong_t *k = kbuf;
+        const compat_ulong_t __user *u = ubuf;
+        compat_ulong_t reg;
+
+        if (target->thread.regs == NULL)
+                return -EIO;
+
+        CHECK_FULL_REGS(target->thread.regs);
+
+        pos /= sizeof(reg);
+        count /= sizeof(reg);
+
+        if (kbuf)
+                for (; count > 0 && pos < PT_MSR; --count)
+                        regs[pos++] = *k++;
+        else
+                for (; count > 0 && pos < PT_MSR; --count) {
+                        if (__get_user(reg, u++))
+                                return -EFAULT;
+                        regs[pos++] = reg;
+                }
+
+
+        if (count > 0 && pos == PT_MSR) {
+                if (kbuf)
+                        reg = *k++;
+                else if (__get_user(reg, u++))
+                        return -EFAULT;
+                set_user_msr(target, reg);
+                ++pos;
+                --count;
+        }
+
+        if (kbuf)
+                for (; count > 0 && pos <= PT_MAX_PUT_REG; --count)
+                        regs[pos++] = *k++;
+        else
+                for (; count > 0 && pos <= PT_MAX_PUT_REG; --count) {
+                        if (__get_user(reg, u++))
+                                return -EFAULT;
+                        regs[pos++] = reg;
+                }
+
+        if (count > 0 && pos == PT_TRAP) {
+                if (kbuf)
+                        reg = *k++;
+                else if (__get_user(reg, u++))
+                        return -EFAULT;
+                set_user_trap(target, reg);
+                ++pos;
+                --count;
+        }
+
+        kbuf = k;
+        ubuf = u;
+        pos *= sizeof(reg);
+        count *= sizeof(reg);
+        return user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
+                                         (PT_TRAP + 1) * sizeof(reg), -1);
+}
+
+/*
+ * These are the regset flavors matching the CONFIG_PPC32 native set.
+ */
+static const struct user_regset compat_regsets[] = {
+        [REGSET_GPR] = {
+                .core_note_type = NT_PRSTATUS, .n = ELF_NGREG,
+                .size = sizeof(compat_long_t), .align = sizeof(compat_long_t),
+                .get = gpr32_get, .set = gpr32_set
+        },
+        [REGSET_FPR] = {
+                .core_note_type = NT_PRFPREG, .n = ELF_NFPREG,
+                .size = sizeof(double), .align = sizeof(double),
+                .get = fpr_get, .set = fpr_set
+        },
+#ifdef CONFIG_ALTIVEC
+        [REGSET_VMX] = {
+                .core_note_type = NT_PPC_VMX, .n = 34,
+                .size = sizeof(vector128), .align = sizeof(vector128),
+                .active = vr_active, .get = vr_get, .set = vr_set
+        },
+#endif
+#ifdef CONFIG_SPE
+        [REGSET_SPE] = {
+                .n = 35,
+                .size = sizeof(u32), .align = sizeof(u32),
+                .active = evr_active, .get = evr_get, .set = evr_set
+        },
+#endif
+};
+
+static const struct user_regset_view user_ppc_compat_view = {
+        .name = "ppc", .e_machine = EM_PPC, .ei_osabi = ELF_OSABI,
+        .regsets = compat_regsets, .n = ARRAY_SIZE(compat_regsets)
+};
+#endif  /* CONFIG_PPC64 */
+
 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
 {
+#ifdef CONFIG_PPC64
+        if (test_tsk_thread_flag(task, TIF_32BIT))
+                return &user_ppc_compat_view;
+#endif
         return &user_ppc_native_view;
 }