ftrace/x86: Add save_regs for i386 function calls
Add saving full regs for function tracing on i386. The saving of regs was influenced by patches sent out by Masami Hiramatsu. Link: Link: http://lkml.kernel.org/r/20120711195745.379060003@goodmis.org Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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@ -40,10 +40,8 @@
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#ifdef CONFIG_DYNAMIC_FTRACE
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#ifdef CONFIG_DYNAMIC_FTRACE
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#define ARCH_SUPPORTS_FTRACE_OPS 1
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#define ARCH_SUPPORTS_FTRACE_OPS 1
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#ifdef CONFIG_X86_64
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#define ARCH_SUPPORTS_FTRACE_SAVE_REGS
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#define ARCH_SUPPORTS_FTRACE_SAVE_REGS
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#endif
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#endif
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#endif
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#ifndef __ASSEMBLY__
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#ifndef __ASSEMBLY__
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extern void mcount(void);
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extern void mcount(void);
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@ -1123,6 +1123,7 @@ ftrace_call:
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popl %edx
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popl %edx
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popl %ecx
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popl %ecx
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popl %eax
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popl %eax
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ftrace_ret:
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#ifdef CONFIG_FUNCTION_GRAPH_TRACER
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#ifdef CONFIG_FUNCTION_GRAPH_TRACER
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.globl ftrace_graph_call
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.globl ftrace_graph_call
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ftrace_graph_call:
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ftrace_graph_call:
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@ -1134,6 +1135,73 @@ ftrace_stub:
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ret
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ret
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END(ftrace_caller)
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END(ftrace_caller)
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ENTRY(ftrace_regs_caller)
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pushf /* push flags before compare (in cs location) */
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cmpl $0, function_trace_stop
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jne ftrace_restore_flags
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/*
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* i386 does not save SS and ESP when coming from kernel.
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* Instead, to get sp, ®s->sp is used (see ptrace.h).
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* Unfortunately, that means eflags must be at the same location
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* as the current return ip is. We move the return ip into the
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* ip location, and move flags into the return ip location.
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*/
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pushl 4(%esp) /* save return ip into ip slot */
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subl $MCOUNT_INSN_SIZE, (%esp) /* Adjust ip */
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pushl $0 /* Load 0 into orig_ax */
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pushl %gs
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pushl %fs
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pushl %es
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pushl %ds
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pushl %eax
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pushl %ebp
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pushl %edi
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pushl %esi
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pushl %edx
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pushl %ecx
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pushl %ebx
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movl 13*4(%esp), %eax /* Get the saved flags */
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movl %eax, 14*4(%esp) /* Move saved flags into regs->flags location */
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/* clobbering return ip */
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movl $__KERNEL_CS,13*4(%esp)
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movl 12*4(%esp), %eax /* Load ip (1st parameter) */
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movl 0x4(%ebp), %edx /* Load parent ip (2cd parameter) */
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lea (%esp), %ecx
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pushl %ecx /* Save pt_regs as 4th parameter */
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leal function_trace_op, %ecx /* Save ftrace_pos in 3rd parameter */
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GLOBAL(ftrace_regs_call)
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call ftrace_stub
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addl $4, %esp /* Skip pt_regs */
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movl 14*4(%esp), %eax /* Move flags back into cs */
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movl %eax, 13*4(%esp) /* Needed to keep addl from modifying flags */
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movl 12*4(%esp), %eax /* Get return ip from regs->ip */
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addl $MCOUNT_INSN_SIZE, %eax
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movl %eax, 14*4(%esp) /* Put return ip back for ret */
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popl %ebx
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popl %ecx
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popl %edx
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popl %esi
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popl %edi
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popl %ebp
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popl %eax
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popl %ds
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popl %es
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popl %fs
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popl %gs
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addl $8, %esp /* Skip orig_ax and ip */
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popf /* Pop flags at end (no addl to corrupt flags) */
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jmp ftrace_ret
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ftrace_restore_flags:
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popf
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jmp ftrace_stub
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#else /* ! CONFIG_DYNAMIC_FTRACE */
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#else /* ! CONFIG_DYNAMIC_FTRACE */
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ENTRY(mcount)
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ENTRY(mcount)
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@ -206,7 +206,6 @@ static int
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ftrace_modify_code(unsigned long ip, unsigned const char *old_code,
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ftrace_modify_code(unsigned long ip, unsigned const char *old_code,
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unsigned const char *new_code);
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unsigned const char *new_code);
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#ifdef ARCH_SUPPORTS_FTRACE_SAVE_REGS
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/*
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/*
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* Should never be called:
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* Should never be called:
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* As it is only called by __ftrace_replace_code() which is called by
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* As it is only called by __ftrace_replace_code() which is called by
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@ -221,7 +220,6 @@ int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
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WARN_ON(1);
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WARN_ON(1);
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return -EINVAL;
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return -EINVAL;
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}
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}
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#endif
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int ftrace_update_ftrace_func(ftrace_func_t func)
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int ftrace_update_ftrace_func(ftrace_func_t func)
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{
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{
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@ -237,7 +235,6 @@ int ftrace_update_ftrace_func(ftrace_func_t func)
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ret = ftrace_modify_code(ip, old, new);
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ret = ftrace_modify_code(ip, old, new);
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#ifdef ARCH_SUPPORTS_FTRACE_SAVE_REGS
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/* Also update the regs callback function */
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/* Also update the regs callback function */
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if (!ret) {
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if (!ret) {
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ip = (unsigned long)(&ftrace_regs_call);
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ip = (unsigned long)(&ftrace_regs_call);
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@ -245,7 +242,6 @@ int ftrace_update_ftrace_func(ftrace_func_t func)
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new = ftrace_call_replace(ip, (unsigned long)func);
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new = ftrace_call_replace(ip, (unsigned long)func);
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ret = ftrace_modify_code(ip, old, new);
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ret = ftrace_modify_code(ip, old, new);
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}
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}
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#endif
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atomic_dec(&modifying_ftrace_code);
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atomic_dec(&modifying_ftrace_code);
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