[PATCH] MIPS: Mask jump target in ftrace_dyn_arch_init_insns().

[PATCH] MIPS: Mask jump target in ftrace_dyn_arch_init_insns().

[David Daney]

The current code is abusing the uasm interface by passing jump target
addresses with high bits set.  Mask the addresses to avoid annoying
messages at boot time.

Signed-off-by: David Daney <ddaney@caviumnetworks.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Wu Zhangjin <wuzhangjin@gmail.com>
---
 arch/mips/kernel/ftrace.c |    5 +++--
 1 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/arch/mips/kernel/ftrace.c b/arch/mips/kernel/ftrace.c
index 5a84a1f..72008b5 100644
--- a/arch/mips/kernel/ftrace.c
+++ b/arch/mips/kernel/ftrace.c
@@ -37,6 +37,7 @@ static inline int in_module(unsigned long ip)
 
 #define JAL 0x0c000000		/* jump & link: ip --> ra, jump to target */
 #define ADDR_MASK 0x03ffffff	/*  op_code|addr : 31...26|25 ....0 */
+#define JUMP_RANGE_MASK ((1UL << 28) - 1)
 
 #define INSN_B_1F_4 0x10000004	/* b 1f; offset = 4 */
 #define INSN_B_1F_5 0x10000005	/* b 1f; offset = 5 */
@@ -60,12 +61,12 @@ static inline void ftrace_dyn_arch_init_insns(void)
 
 	/* jal (ftrace_caller + 8), jump over the first two instruction */
 	buf = (u32 *)&insn_jal_ftrace_caller;
-	uasm_i_jal(&buf, (FTRACE_ADDR + 8));
+	uasm_i_jal(&buf, (FTRACE_ADDR + 8) & JUMP_RANGE_MASK);
 
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 	/* j ftrace_graph_caller */
 	buf = (u32 *)&insn_j_ftrace_graph_caller;
-	uasm_i_j(&buf, (unsigned long)ftrace_graph_caller);
+	uasm_i_j(&buf, (unsigned long)ftrace_graph_caller & JUMP_RANGE_MASK);
 #endif
 }
 
-- 
1.7.2.3

Re: [PATCH] MIPS: Mask jump target in ftrace_dyn_arch_init_insns().

[Ralf Baechle]

On Tue, Dec 28, 2010 at 01:21:37PM -0800, David Daney wrote:

> The current code is abusing the uasm interface by passing jump target
> addresses with high bits set.  Mask the addresses to avoid annoying
> messages at boot time.
> 
> Signed-off-by: David Daney <ddaney@caviumnetworks.com>
> Cc: Steven Rostedt <rostedt@goodmis.org>
> Cc: Wu Zhangjin <wuzhangjin@gmail.com>

Thanks, applied.

  Ralf