powerpc: Fix ptrace compat wrapper for FPU register access

The ptrace compat wrapper mishandles access to the fpu registers.  The
PTRACE_PEEKUSR and PTRACE_POKEUSR requests miscalculate the index into
the fpr array due to the broken FPINDEX macro.  The
PPC_PTRACE_PEEKUSR_3264 request needs to use the same formula that the
native ptrace interface uses when operating on the register number (as
opposed to the 4-byte offset).  The PPC_PTRACE_POKEUSR_3264 request
didn't take TS_FPRWIDTH into account.

Signed-off-by: Andreas Schwab <schwab@linux-m68k.org>
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>

diff --git a/arch/powerpc/kernel/ptrace32.c b/arch/powerpc/kernel/ptrace32.c
index 197d49c..297632c 100644 (file)
--- a/arch/powerpc/kernel/ptrace32.c
+++ b/arch/powerpc/kernel/ptrace32.c
@@ -67,7 +67,8 @@ static long compat_ptrace_old(struct task_struct *child, long request,
 /* Macros to workout the correct index for the FPR in the thread struct */
 #define FPRNUMBER(i) (((i) - PT_FPR0) >> 1)
 #define FPRHALF(i) (((i) - PT_FPR0) & 1)
-#define FPRINDEX(i) TS_FPRWIDTH * FPRNUMBER(i) + FPRHALF(i)
+#define FPRINDEX(i) TS_FPRWIDTH * FPRNUMBER(i) * 2 + FPRHALF(i)
+#define FPRINDEX_3264(i) (TS_FPRWIDTH * ((i) - PT_FPR0))
 
 long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
                        compat_ulong_t caddr, compat_ulong_t cdata)
@@ -168,8 +169,9 @@ long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
                CHECK_FULL_REGS(child->thread.regs);
                if (numReg >= PT_FPR0) {
                        flush_fp_to_thread(child);
-                       tmp = ((unsigned long int *)child->thread.fpr)
-                               [FPRINDEX(numReg)];
+                       /* get 64 bit FPR */
+                       tmp = ((u64 *)child->thread.fpr)
+                               [FPRINDEX_3264(numReg)];
                } else { /* register within PT_REGS struct */
                        tmp = ptrace_get_reg(child, numReg);
                } 
@@ -262,8 +264,13 @@ long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
                                freg = (freg & 0xfffffffful) | (data << 32);
                        ret = ptrace_put_reg(child, numReg, freg);
                } else {
+                       u64 *tmp;
                        flush_fp_to_thread(child);
-                       ((unsigned int *)child->thread.regs)[index] = data;
+                       /* get 64 bit FPR ... */
+                       tmp = &(((u64 *)child->thread.fpr)
+                               [FPRINDEX_3264(numReg)]);
+                       /* ... write the 32 bit part we want */
+                       ((u32 *)tmp)[index % 2] = data;
                        ret = 0;
                }
                break;