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authorSteven Rostedt <srostedt@redhat.com>2009-06-18 12:45:08 -0400
committerSteven Rostedt <rostedt@goodmis.org>2009-06-18 18:40:18 -0400
commit71e308a239c098673570d0b417d42262bb535909 (patch)
treea9e415d0ae6302e820a1f9d4ff55a724b3a12cf6 /arch/x86
parenteb4a03780d4c4464ef2ad86d80cca3f3284fe81d (diff)
function-graph: add stack frame test
In case gcc does something funny with the stack frames, or the return from function code, we would like to detect that. An arch may implement passing of a variable that is unique to the function and can be saved on entering a function and can be tested when exiting the function. Usually the frame pointer can be used for this purpose. This patch also implements this for x86. Where it passes in the stack frame of the parent function, and will test that frame on exit. There was a case in x86_32 with optimize for size (-Os) where, for a few functions, gcc would align the stack frame and place a copy of the return address into it. The function graph tracer modified the copy and not the actual return address. On return from the funtion, it did not go to the tracer hook, but returned to the parent. This broke the function graph tracer, because the return of the parent (where gcc did not do this funky manipulation) returned to the location that the child function was suppose to. This caused strange kernel crashes. This test detected the problem and pointed out where the issue was. This modifies the parameters of one of the functions that the arch specific code calls, so it includes changes to arch code to accommodate the new prototype. Note, I notice that the parsic arch implements its own push_return_trace. This is now a generic function and the ftrace_push_return_trace should be used instead. This patch does not touch that code. Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Helge Deller <deller@gmx.de> Cc: Kyle McMartin <kyle@mcmartin.ca> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'arch/x86')
-rw-r--r--arch/x86/Kconfig1
-rw-r--r--arch/x86/kernel/entry_32.S2
-rw-r--r--arch/x86/kernel/entry_64.S2
-rw-r--r--arch/x86/kernel/ftrace.c6
4 files changed, 9 insertions, 2 deletions
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 356d2ec8e2fb..fcf12af07427 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -33,6 +33,7 @@ config X86
33 select HAVE_DYNAMIC_FTRACE 33 select HAVE_DYNAMIC_FTRACE
34 select HAVE_FUNCTION_TRACER 34 select HAVE_FUNCTION_TRACER
35 select HAVE_FUNCTION_GRAPH_TRACER 35 select HAVE_FUNCTION_GRAPH_TRACER
36 select HAVE_FUNCTION_GRAPH_FP_TEST
36 select HAVE_FUNCTION_TRACE_MCOUNT_TEST 37 select HAVE_FUNCTION_TRACE_MCOUNT_TEST
37 select HAVE_FTRACE_NMI_ENTER if DYNAMIC_FTRACE 38 select HAVE_FTRACE_NMI_ENTER if DYNAMIC_FTRACE
38 select HAVE_FTRACE_SYSCALLS 39 select HAVE_FTRACE_SYSCALLS
diff --git a/arch/x86/kernel/entry_32.S b/arch/x86/kernel/entry_32.S
index c929add475c9..0d4b28564c14 100644
--- a/arch/x86/kernel/entry_32.S
+++ b/arch/x86/kernel/entry_32.S
@@ -1154,6 +1154,7 @@ ENTRY(ftrace_graph_caller)
1154 pushl %edx 1154 pushl %edx
1155 movl 0xc(%esp), %edx 1155 movl 0xc(%esp), %edx
1156 lea 0x4(%ebp), %eax 1156 lea 0x4(%ebp), %eax
1157 movl (%ebp), %ecx
1157 subl $MCOUNT_INSN_SIZE, %edx 1158 subl $MCOUNT_INSN_SIZE, %edx
1158 call prepare_ftrace_return 1159 call prepare_ftrace_return
1159 popl %edx 1160 popl %edx
@@ -1168,6 +1169,7 @@ return_to_handler:
1168 pushl %eax 1169 pushl %eax
1169 pushl %ecx 1170 pushl %ecx
1170 pushl %edx 1171 pushl %edx
1172 movl %ebp, %eax
1171 call ftrace_return_to_handler 1173 call ftrace_return_to_handler
1172 movl %eax, 0xc(%esp) 1174 movl %eax, 0xc(%esp)
1173 popl %edx 1175 popl %edx
diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index de74f0a3e0ed..c251be745107 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -135,6 +135,7 @@ ENTRY(ftrace_graph_caller)
135 135
136 leaq 8(%rbp), %rdi 136 leaq 8(%rbp), %rdi
137 movq 0x38(%rsp), %rsi 137 movq 0x38(%rsp), %rsi
138 movq (%rbp), %rdx
138 subq $MCOUNT_INSN_SIZE, %rsi 139 subq $MCOUNT_INSN_SIZE, %rsi
139 140
140 call prepare_ftrace_return 141 call prepare_ftrace_return
@@ -150,6 +151,7 @@ GLOBAL(return_to_handler)
150 /* Save the return values */ 151 /* Save the return values */
151 movq %rax, (%rsp) 152 movq %rax, (%rsp)
152 movq %rdx, 8(%rsp) 153 movq %rdx, 8(%rsp)
154 movq %rbp, %rdi
153 155
154 call ftrace_return_to_handler 156 call ftrace_return_to_handler
155 157
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index b79c5533c421..d94e1ea3b9fe 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -408,7 +408,8 @@ int ftrace_disable_ftrace_graph_caller(void)
408 * Hook the return address and push it in the stack of return addrs 408 * Hook the return address and push it in the stack of return addrs
409 * in current thread info. 409 * in current thread info.
410 */ 410 */
411void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr) 411void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr,
412 unsigned long frame_pointer)
412{ 413{
413 unsigned long old; 414 unsigned long old;
414 int faulted; 415 int faulted;
@@ -453,7 +454,8 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr)
453 return; 454 return;
454 } 455 }
455 456
456 if (ftrace_push_return_trace(old, self_addr, &trace.depth) == -EBUSY) { 457 if (ftrace_push_return_trace(old, self_addr, &trace.depth,
458 frame_pointer) == -EBUSY) {
457 *parent = old; 459 *parent = old;
458 return; 460 return;
459 } 461 }