[PATCH][PPC32] Fix SPE state corruption on e500

[Kumar Gala]

Linus,

Unfortunately the restoring of SPE state was causing data corruption since 
we were restoring based on the size of the altivec context and not 
the SPE context.  Also, fixed setting of last_task_used_spe on 
start_thread, flush_thread, and exit_thread.

Patch should go in for 2.6.10.

Signed-off-by: Kumar Gala <kumar.gala at freescale.com>

--

diff -Nru a/arch/ppc/kernel/process.c b/arch/ppc/kernel/process.c
--- a/arch/ppc/kernel/process.c 2004-12-14 15:59:07 -06:00
+++ b/arch/ppc/kernel/process.c 2004-12-14 15:59:07 -06:00
@@ -321,7 +321,7 @@
        trap = TRAP(regs);
        if (trap == 0x300 || trap == 0x600)
                printk("DAR: %08lX, DSISR: %08lX\n", regs->dar, regs->dsisr);
-       printk("TASK = %p[%d] '%s' THREAD: %p",
+       printk("TASK = %p[%d] '%s' THREAD: %p\n",
               current, current->pid, current->comm, current->thread_info);
        printk("Last syscall: %ld ", current->thread.last_syscall);
 
@@ -370,6 +370,10 @@
                last_task_used_math = NULL;
        if (last_task_used_altivec == current)
                last_task_used_altivec = NULL;
+#ifdef CONFIG_SPE
+       if (last_task_used_spe == current)
+               last_task_used_spe = NULL;
+#endif
 }
 
 void flush_thread(void)
@@ -378,6 +382,10 @@
                last_task_used_math = NULL;
        if (last_task_used_altivec == current)
                last_task_used_altivec = NULL;
+#ifdef CONFIG_SPE
+       if (last_task_used_spe == current)
+               last_task_used_spe = NULL;
+#endif
 }
 
 void
@@ -480,6 +488,10 @@
                last_task_used_math = NULL;
        if (last_task_used_altivec == current)
                last_task_used_altivec = NULL;
+#ifdef CONFIG_SPE
+       if (last_task_used_spe == current)
+               last_task_used_spe = NULL;
+#endif
        memset(current->thread.fpr, 0, sizeof(current->thread.fpr));
        current->thread.fpscr = 0;
 #ifdef CONFIG_ALTIVEC
diff -Nru a/arch/ppc/kernel/signal.c b/arch/ppc/kernel/signal.c
--- a/arch/ppc/kernel/signal.c  2004-12-14 15:59:07 -06:00
+++ b/arch/ppc/kernel/signal.c  2004-12-14 15:59:07 -06:00
@@ -319,7 +319,7 @@
        if (!__get_user(msr, &sr->mc_gregs[PT_MSR]) && (msr & MSR_SPE) != 0) {
                /* restore spe registers from the stack */
                if (__copy_from_user(current->thread.evr, &sr->mc_vregs,
-                                    sizeof(sr->mc_vregs)))
+                                    ELF_NEVRREG * sizeof(u32)))
                        return 1;
        } else if (current->thread.used_spe)
                memset(&current->thread.evr, 0, ELF_NEVRREG * sizeof(u32));