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-rw-r--r--Makefile6
-rw-r--r--arch/x86/Kconfig1
-rw-r--r--arch/x86/include/asm/ftrace.h7
-rw-r--r--arch/x86/kernel/entry_64.S32
-rw-r--r--arch/x86/kernel/x8664_ksyms_64.c6
-rw-r--r--kernel/trace/Kconfig5
-rw-r--r--kernel/trace/trace_functions_graph.c5
-rw-r--r--scripts/recordmcount.h4
8 files changed, 56 insertions, 10 deletions
diff --git a/Makefile b/Makefile
index ddf5be952e45..e7ca93f17851 100644
--- a/Makefile
+++ b/Makefile
@@ -609,7 +609,11 @@ KBUILD_CFLAGS += $(call cc-option, -femit-struct-debug-baseonly)
endif
ifdef CONFIG_FUNCTION_TRACER
-KBUILD_CFLAGS += -pg
+ifdef CONFIG_HAVE_FENTRY
+CC_USING_FENTRY := $(call cc-option, -mfentry -DCC_USING_FENTRY)
+endif
+KBUILD_CFLAGS += -pg $(CC_USING_FENTRY)
+KBUILD_AFLAGS += $(CC_USING_FENTRY)
ifdef CONFIG_DYNAMIC_FTRACE
ifdef CONFIG_HAVE_C_RECORDMCOUNT
BUILD_C_RECORDMCOUNT := y
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index a2d19ee750ca..28dd891a0a16 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -36,6 +36,7 @@ config X86
select HAVE_KRETPROBES
select HAVE_OPTPROBES
select HAVE_FTRACE_MCOUNT_RECORD
+ select HAVE_FENTRY if X86_64
select HAVE_C_RECORDMCOUNT
select HAVE_DYNAMIC_FTRACE
select HAVE_FUNCTION_TRACER
diff --git a/arch/x86/include/asm/ftrace.h b/arch/x86/include/asm/ftrace.h
index a6cae0c1720c..9a25b522d377 100644
--- a/arch/x86/include/asm/ftrace.h
+++ b/arch/x86/include/asm/ftrace.h
@@ -35,7 +35,11 @@
#endif
#ifdef CONFIG_FUNCTION_TRACER
-#define MCOUNT_ADDR ((long)(mcount))
+#ifdef CC_USING_FENTRY
+# define MCOUNT_ADDR ((long)(__fentry__))
+#else
+# define MCOUNT_ADDR ((long)(mcount))
+#endif
#define MCOUNT_INSN_SIZE 5 /* sizeof mcount call */
#ifdef CONFIG_DYNAMIC_FTRACE
@@ -46,6 +50,7 @@
#ifndef __ASSEMBLY__
extern void mcount(void);
extern atomic_t modifying_ftrace_code;
+extern void __fentry__(void);
static inline unsigned long ftrace_call_adjust(unsigned long addr)
{
diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index b7a81dcb7366..ed767b747fe5 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -68,10 +68,18 @@
.section .entry.text, "ax"
#ifdef CONFIG_FUNCTION_TRACER
+
+#ifdef CC_USING_FENTRY
+# define function_hook __fentry__
+#else
+# define function_hook mcount
+#endif
+
#ifdef CONFIG_DYNAMIC_FTRACE
-ENTRY(mcount)
+
+ENTRY(function_hook)
retq
-END(mcount)
+END(function_hook)
/* skip is set if stack has been adjusted */
.macro ftrace_caller_setup skip=0
@@ -84,7 +92,11 @@ END(mcount)
movq RIP(%rsp), %rdi
subq $MCOUNT_INSN_SIZE, %rdi
/* Load the parent_ip into the second parameter */
+#ifdef CC_USING_FENTRY
+ movq SS+16(%rsp), %rsi
+#else
movq 8(%rbp), %rsi
+#endif
.endm
ENTRY(ftrace_caller)
@@ -177,7 +189,8 @@ END(ftrace_regs_caller)
#else /* ! CONFIG_DYNAMIC_FTRACE */
-ENTRY(mcount)
+
+ENTRY(function_hook)
cmpl $0, function_trace_stop
jne ftrace_stub
@@ -199,7 +212,11 @@ trace:
MCOUNT_SAVE_FRAME
movq RIP(%rsp), %rdi
+#ifdef CC_USING_FENTRY
+ movq SS+16(%rsp), %rsi
+#else
movq 8(%rbp), %rsi
+#endif
subq $MCOUNT_INSN_SIZE, %rdi
call *ftrace_trace_function
@@ -207,7 +224,7 @@ trace:
MCOUNT_RESTORE_FRAME
jmp ftrace_stub
-END(mcount)
+END(function_hook)
#endif /* CONFIG_DYNAMIC_FTRACE */
#endif /* CONFIG_FUNCTION_TRACER */
@@ -215,9 +232,14 @@ END(mcount)
ENTRY(ftrace_graph_caller)
MCOUNT_SAVE_FRAME
+#ifdef CC_USING_FENTRY
+ leaq SS+16(%rsp), %rdi
+ movq $0, %rdx /* No framepointers needed */
+#else
leaq 8(%rbp), %rdi
- movq RIP(%rsp), %rsi
movq (%rbp), %rdx
+#endif
+ movq RIP(%rsp), %rsi
subq $MCOUNT_INSN_SIZE, %rsi
call prepare_ftrace_return
diff --git a/arch/x86/kernel/x8664_ksyms_64.c b/arch/x86/kernel/x8664_ksyms_64.c
index 6020f6f5927c..1330dd102950 100644
--- a/arch/x86/kernel/x8664_ksyms_64.c
+++ b/arch/x86/kernel/x8664_ksyms_64.c
@@ -13,9 +13,13 @@
#include <asm/ftrace.h>
#ifdef CONFIG_FUNCTION_TRACER
-/* mcount is defined in assembly */
+/* mcount and __fentry__ are defined in assembly */
+#ifdef CC_USING_FENTRY
+EXPORT_SYMBOL(__fentry__);
+#else
EXPORT_SYMBOL(mcount);
#endif
+#endif
EXPORT_SYMBOL(__get_user_1);
EXPORT_SYMBOL(__get_user_2);
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index 8c4c07071cc5..9301a0e35e0c 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -49,6 +49,11 @@ config HAVE_SYSCALL_TRACEPOINTS
help
See Documentation/trace/ftrace-design.txt
+config HAVE_FENTRY
+ bool
+ help
+ Arch supports the gcc options -pg with -mfentry
+
config HAVE_C_RECORDMCOUNT
bool
help
diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
index ce27c8ba8d31..99b4378393d5 100644
--- a/kernel/trace/trace_functions_graph.c
+++ b/kernel/trace/trace_functions_graph.c
@@ -143,7 +143,7 @@ ftrace_pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret,
return;
}
-#ifdef CONFIG_HAVE_FUNCTION_GRAPH_FP_TEST
+#if defined(CONFIG_HAVE_FUNCTION_GRAPH_FP_TEST) && !defined(CC_USING_FENTRY)
/*
* The arch may choose to record the frame pointer used
* and check it here to make sure that it is what we expect it
@@ -154,6 +154,9 @@ ftrace_pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret,
*
* Currently, x86_32 with optimize for size (-Os) makes the latest
* gcc do the above.
+ *
+ * Note, -mfentry does not use frame pointers, and this test
+ * is not needed if CC_USING_FENTRY is set.
*/
if (unlikely(current->ret_stack[index].fp != frame_pointer)) {
ftrace_graph_stop();
diff --git a/scripts/recordmcount.h b/scripts/recordmcount.h
index 54e35c1e5948..9d1421e63ff8 100644
--- a/scripts/recordmcount.h
+++ b/scripts/recordmcount.h
@@ -261,11 +261,13 @@ static unsigned get_mcountsym(Elf_Sym const *const sym0,
&sym0[Elf_r_sym(relp)];
char const *symname = &str0[w(symp->st_name)];
char const *mcount = gpfx == '_' ? "_mcount" : "mcount";
+ char const *fentry = "__fentry__";
if (symname[0] == '.')
++symname; /* ppc64 hack */
if (strcmp(mcount, symname) == 0 ||
- (altmcount && strcmp(altmcount, symname) == 0))
+ (altmcount && strcmp(altmcount, symname) == 0) ||
+ (strcmp(fentry, symname) == 0))
mcountsym = Elf_r_sym(relp);
return mcountsym;