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Diffstat (limited to 'arch/mips/kernel/ftrace.c')
-rw-r--r--arch/mips/kernel/ftrace.c36
1 files changed, 35 insertions, 1 deletions
diff --git a/arch/mips/kernel/ftrace.c b/arch/mips/kernel/ftrace.c
index 6a2d758dd8e9..83fa1460e294 100644
--- a/arch/mips/kernel/ftrace.c
+++ b/arch/mips/kernel/ftrace.c
@@ -25,6 +25,12 @@
#define MCOUNT_OFFSET_INSNS 4
#endif
+/* Arch override because MIPS doesn't need to run this from stop_machine() */
+void arch_ftrace_update_code(int command)
+{
+ ftrace_modify_all_code(command);
+}
+
/*
* Check if the address is in kernel space
*
@@ -89,6 +95,24 @@ static int ftrace_modify_code(unsigned long ip, unsigned int new_code)
return 0;
}
+#ifndef CONFIG_64BIT
+static int ftrace_modify_code_2(unsigned long ip, unsigned int new_code1,
+ unsigned int new_code2)
+{
+ int faulted;
+
+ safe_store_code(new_code1, ip, faulted);
+ if (unlikely(faulted))
+ return -EFAULT;
+ ip += 4;
+ safe_store_code(new_code2, ip, faulted);
+ if (unlikely(faulted))
+ return -EFAULT;
+ flush_icache_range(ip, ip + 8); /* original ip + 12 */
+ return 0;
+}
+#endif
+
/*
* The details about the calling site of mcount on MIPS
*
@@ -131,8 +155,18 @@ int ftrace_make_nop(struct module *mod,
* needed.
*/
new = in_kernel_space(ip) ? INSN_NOP : INSN_B_1F;
-
+#ifdef CONFIG_64BIT
return ftrace_modify_code(ip, new);
+#else
+ /*
+ * On 32 bit MIPS platforms, gcc adds a stack adjust
+ * instruction in the delay slot after the branch to
+ * mcount and expects mcount to restore the sp on return.
+ * This is based on a legacy API and does nothing but
+ * waste instructions so it's being removed at runtime.
+ */
+ return ftrace_modify_code_2(ip, new, INSN_NOP);
+#endif
}
int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)