arm64: rockchip_defconfig: enable CONFIG_PHY_ROCKCHIP_DP

[firefly-linux-kernel-4.4.55.git] / arch / arm64 / kernel / ftrace.c

diff --git a/arch/arm64/kernel/ftrace.c b/arch/arm64/kernel/ftrace.c
index 649890a3ac4e747cd49884f8e0d07a3bc7959bb8..ebecf9aa33d12da8a564ea0314f59a71b89e64a0 100644 (file)
--- a/arch/arm64/kernel/ftrace.c
+++ b/arch/arm64/kernel/ftrace.c
@@ -29,12 +29,11 @@ static int ftrace_modify_code(unsigned long pc, u32 old, u32 new,
 
        /*
         * Note:
-        * Due to modules and __init, code can disappear and change,
-        * we need to protect against faulting as well as code changing.
-        * We do this by aarch64_insn_*() which use the probe_kernel_*().
-        *
-        * No lock is held here because all the modifications are run
-        * through stop_machine().
+        * We are paranoid about modifying text, as if a bug were to happen, it
+        * could cause us to read or write to someplace that could cause harm.
+        * Carefully read and modify the code with aarch64_insn_*() which uses
+        * probe_kernel_*(), and make sure what we read is what we expected it
+        * to be before modifying it.
         */
        if (validate) {
                if (aarch64_insn_read((void *)pc, &replaced))
@@ -58,7 +57,8 @@ int ftrace_update_ftrace_func(ftrace_func_t func)
        u32 new;
 
        pc = (unsigned long)&ftrace_call;
-       new = aarch64_insn_gen_branch_imm(pc, (unsigned long)func, true);
+       new = aarch64_insn_gen_branch_imm(pc, (unsigned long)func,
+                                         AARCH64_INSN_BRANCH_LINK);
 
        return ftrace_modify_code(pc, 0, new, false);
 }
@@ -72,7 +72,7 @@ int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
        u32 old, new;
 
        old = aarch64_insn_gen_nop();
-       new = aarch64_insn_gen_branch_imm(pc, addr, true);
+       new = aarch64_insn_gen_branch_imm(pc, addr, AARCH64_INSN_BRANCH_LINK);
 
        return ftrace_modify_code(pc, old, new, true);
 }
@@ -86,15 +86,19 @@ int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec,
        unsigned long pc = rec->ip;
        u32 old, new;
 
-       old = aarch64_insn_gen_branch_imm(pc, addr, true);
+       old = aarch64_insn_gen_branch_imm(pc, addr, AARCH64_INSN_BRANCH_LINK);
        new = aarch64_insn_gen_nop();
 
        return ftrace_modify_code(pc, old, new, true);
 }
 
-int __init ftrace_dyn_arch_init(void *data)
+void arch_ftrace_update_code(int command)
+{
+       ftrace_modify_all_code(command);
+}
+
+int __init ftrace_dyn_arch_init(void)
 {
-       *(unsigned long *)data = 0;
        return 0;
 }
 #endif /* CONFIG_DYNAMIC_FTRACE */
@@ -125,23 +129,20 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr,
         * on other archs. It's unlikely on AArch64.
         */
        old = *parent;
-       *parent = return_hooker;
 
        trace.func = self_addr;
        trace.depth = current->curr_ret_stack + 1;
 
        /* Only trace if the calling function expects to */
-       if (!ftrace_graph_entry(&trace)) {
-               *parent = old;
+       if (!ftrace_graph_entry(&trace))
                return;
-       }
 
        err = ftrace_push_return_trace(old, self_addr, &trace.depth,
                                       frame_pointer);
-       if (err == -EBUSY) {
-               *parent = old;
+       if (err == -EBUSY)
                return;
-       }
+       else
+               *parent = return_hooker;
 }
 
 #ifdef CONFIG_DYNAMIC_FTRACE
@@ -155,7 +156,8 @@ static int ftrace_modify_graph_caller(bool enable)
        u32 branch, nop;
 
        branch = aarch64_insn_gen_branch_imm(pc,
-                       (unsigned long)ftrace_graph_caller, false);
+                                            (unsigned long)ftrace_graph_caller,
+                                            AARCH64_INSN_BRANCH_NOLINK);
        nop = aarch64_insn_gen_nop();
 
        if (enable)