x86/ftrace: Add -mfentry support to x86_32 with DYNAMIC_FTRACE set

[karo-tx-linux.git] / arch / x86 / kernel / ftrace_32.S

diff --git a/arch/x86/kernel/ftrace_32.S b/arch/x86/kernel/ftrace_32.S
index 93e26647c3f292e45c555af1c8cd684fa18ef3fb..80518ec5b882aa64c465399600197a5e62f94e43 100644 (file)
--- a/arch/x86/kernel/ftrace_32.S
+++ b/arch/x86/kernel/ftrace_32.S
@@ -9,26 +9,68 @@
 #include <asm/ftrace.h>
 
 #ifdef CONFIG_FUNCTION_TRACER
+
+#ifdef CC_USING_FENTRY
+# define function_hook __fentry__
+EXPORT_SYMBOL(__fentry__)
+#else
+# define function_hook mcount
+EXPORT_SYMBOL(mcount)
+#endif
+
 #ifdef CONFIG_DYNAMIC_FTRACE
 
-ENTRY(mcount)
+/* mcount uses a frame pointer even if CONFIG_FRAME_POINTER is not set */
+#if !defined(CC_USING_FENTRY) || defined(CONFIG_FRAME_POINTER)
+# define USING_FRAME_POINTER
+#endif
+
+#ifdef USING_FRAME_POINTER
+# define MCOUNT_FRAME                  1       /* using frame = true  */
+#else
+# define MCOUNT_FRAME                  0       /* using frame = false */
+#endif
+
+ENTRY(function_hook)
        ret
-END(mcount)
+END(function_hook)
 
 ENTRY(ftrace_caller)
 
+#ifdef USING_FRAME_POINTER
+# ifdef CC_USING_FENTRY
+       /*
+        * Frame pointers are of ip followed by bp.
+        * Since fentry is an immediate jump, we are left with
+        * parent-ip, function-ip. We need to add a frame with
+        * parent-ip followed by ebp.
+        */
+       pushl   4(%esp)                         /* parent ip */
        pushl   %ebp
        movl    %esp, %ebp
-
+       pushl   2*4(%esp)                       /* function ip */
+# endif
+       /* For mcount, the function ip is directly above */
+       pushl   %ebp
+       movl    %esp, %ebp
+#endif
        pushl   %eax
        pushl   %ecx
        pushl   %edx
        pushl   $0                              /* Pass NULL as regs pointer */
-       movl    5*4(%esp), %eax
-       /* Copy original ebp into %edx */
+
+#ifdef USING_FRAME_POINTER
+       /* Load parent ebp into edx */
        movl    4*4(%esp), %edx
+#else
+       /* There's no frame pointer, load the appropriate stack addr instead */
+       lea     4*4(%esp), %edx
+#endif
+
+       movl    (MCOUNT_FRAME+4)*4(%esp), %eax  /* load the rip */
        /* Get the parent ip */
-       movl    0x4(%edx), %edx
+       movl    4(%edx), %edx                   /* edx has ebp */
+
        movl    function_trace_op, %ecx
        subl    $MCOUNT_INSN_SIZE, %eax
 
@@ -40,7 +82,14 @@ ftrace_call:
        popl    %edx
        popl    %ecx
        popl    %eax
+#ifdef USING_FRAME_POINTER
        popl    %ebp
+# ifdef CC_USING_FENTRY
+       addl    $4,%esp                         /* skip function ip */
+       popl    %ebp                            /* this is the orig bp */
+       addl    $4, %esp                        /* skip parent ip */
+# endif
+#endif
 .Lftrace_ret:
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 .globl ftrace_graph_call
@@ -81,6 +130,10 @@ ENTRY(ftrace_regs_caller)
        pushl   %edx
        pushl   %ecx
        pushl   %ebx
+#ifdef CC_USING_FENTRY
+       /* Load 4 off of the parent ip addr into ebp */
+       lea     14*4(%esp), %ebp
+#endif
 
        movl    12*4(%esp), %eax                /* Load ip (1st parameter) */
        subl    $MCOUNT_INSN_SIZE, %eax         /* Adjust ip */
@@ -119,7 +172,7 @@ GLOBAL(ftrace_regs_call)
        jmp     .Lftrace_ret
 #else /* ! CONFIG_DYNAMIC_FTRACE */
 
-ENTRY(mcount)
+ENTRY(function_hook)
        cmpl    $__PAGE_OFFSET, %esp
        jb      ftrace_stub                     /* Paging not enabled yet? */
 
@@ -151,9 +204,8 @@ ftrace_stub:
        popl    %ecx
        popl    %eax
        jmp     ftrace_stub
-END(mcount)
+END(function_hook)
 #endif /* CONFIG_DYNAMIC_FTRACE */
-EXPORT_SYMBOL(mcount)
 #endif /* CONFIG_FUNCTION_TRACER */
 
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
@@ -161,9 +213,15 @@ ENTRY(ftrace_graph_caller)
        pushl   %eax
        pushl   %ecx
        pushl   %edx
-       movl    0xc(%esp), %eax
+       movl    3*4(%esp), %eax
+       /* Even with frame pointers, fentry doesn't have one here */
+#ifdef CC_USING_FENTRY
+       lea     4*4(%esp), %edx
+       movl    $0, %ecx
+#else
        lea     0x4(%ebp), %edx
        movl    (%ebp), %ecx
+#endif
        subl    $MCOUNT_INSN_SIZE, %eax
        call    prepare_ftrace_return
        popl    %edx
@@ -176,7 +234,11 @@ END(ftrace_graph_caller)
 return_to_handler:
        pushl   %eax
        pushl   %edx
+#ifdef CC_USING_FENTRY
+       movl    $0, %eax
+#else
        movl    %ebp, %eax
+#endif
        call    ftrace_return_to_handler
        movl    %eax, %ecx
        popl    %edx