MIPS: kernel: {ftrace,kgdb}: Set correct address limit for cache flushes

When flushing the icache, make sure the address limit is correct
so the appropriate 'cache' instruction will be used. This has no
impact on cores operating in non-eva mode. However, when EVA is
enabled, we ensure that 'cache' will be used instead of 'cachee'.
Signed-off-by: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>

arch/mips/kernel/ftrace.c

@@ -90,6 +90,7 @@ static inline void ftrace_dyn_arch_init_insns(void)
 static int ftrace_modify_code(unsigned long ip, unsigned int new_code)
 {
 	int faulted;
+	mm_segment_t old_fs;
 
 	/* *(unsigned int *)ip = new_code; */
 	safe_store_code(new_code, ip, faulted);
@@ -97,7 +98,10 @@ static int ftrace_modify_code(unsigned long ip, unsigned int new_code)
 	if (unlikely(faulted))
 		return -EFAULT;
 
+	old_fs = get_fs();
+	set_fs(get_ds());
 	flush_icache_range(ip, ip + 8);
+	set_fs(old_fs);
 
 	return 0;
 }

arch/mips/kernel/kgdb.c

@@ -32,6 +32,7 @@
 #include <asm/cacheflush.h>
 #include <asm/processor.h>
 #include <asm/sigcontext.h>
+#include <asm/uaccess.h>
 
 static struct hard_trap_info {
 	unsigned char tt;	/* Trap type code for MIPS R3xxx and R4xxx */
@@ -208,7 +209,14 @@ void arch_kgdb_breakpoint(void)
 
 static void kgdb_call_nmi_hook(void *ignored)
 {
+	mm_segment_t old_fs;
+
+	old_fs = get_fs();
+	set_fs(get_ds());
+
 	kgdb_nmicallback(raw_smp_processor_id(), NULL);
+
+	set_fs(old_fs);
 }
 
 void kgdb_roundup_cpus(unsigned long flags)
@@ -282,6 +290,7 @@ static int kgdb_mips_notify(struct notifier_block *self, unsigned long cmd,
 	struct die_args *args = (struct die_args *)ptr;
 	struct pt_regs *regs = args->regs;
 	int trap = (regs->cp0_cause & 0x7c) >> 2;
+	mm_segment_t old_fs;
 
 #ifdef CONFIG_KPROBES
 	/*
@@ -296,11 +305,17 @@ static int kgdb_mips_notify(struct notifier_block *self, unsigned long cmd,
 	if (user_mode(regs))
 		return NOTIFY_DONE;
 
+	/* Kernel mode. Set correct address limit */
+	old_fs = get_fs();
+	set_fs(get_ds());
+
 	if (atomic_read(&kgdb_active) != -1)
 		kgdb_nmicallback(smp_processor_id(), regs);
 
-	if (kgdb_handle_exception(trap, compute_signal(trap), cmd, regs))
+	if (kgdb_handle_exception(trap, compute_signal(trap), cmd, regs)) {
+		set_fs(old_fs);
 		return NOTIFY_DONE;
+	}
 
 	if (atomic_read(&kgdb_setting_breakpoint))
 		if ((trap == 9) && (regs->cp0_epc == (unsigned long)breakinst))
@@ -310,6 +325,7 @@ static int kgdb_mips_notify(struct notifier_block *self, unsigned long cmd,
 	local_irq_enable();
 	__flush_cache_all();
 
+	set_fs(old_fs);
 	return NOTIFY_STOP;
 }