diff options
| author | Steven Rostedt (Red Hat) <rostedt@goodmis.org> | 2014-11-24 21:38:40 -0500 |
|---|---|---|
| committer | Steven Rostedt <rostedt@goodmis.org> | 2014-12-01 14:08:43 -0500 |
| commit | f1ab00af816ec8e1ad53229963c863fdd6bcf222 (patch) | |
| tree | 91ef3763b2403fd33f88b0e5306dbda4458f1970 /arch/x86 | |
| parent | 0687c36e456ca81feff5f3415e53c1cb8d8efd56 (diff) | |
ftrace/x86: Get rid of ftrace_caller_setup
Move all the work from ftrace_caller_setup into save_mcount_regs. This
simplifies the code and makes it easier to understand.
Link: http://lkml.kernel.org/r/CA+55aFxUTUbdxpjVMW8X9c=o8sui7OB_MYPfcbJuDyfUWtNrNg@mail.gmail.com
Link: http://lkml.kernel.org/r/alpine.DEB.2.11.1411262304010.3961@nanos
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/kernel/mcount_64.S | 71 |
1 files changed, 42 insertions, 29 deletions
diff --git a/arch/x86/kernel/mcount_64.S b/arch/x86/kernel/mcount_64.S index 003b22df1d8..ddc766efa1f 100644 --- a/arch/x86/kernel/mcount_64.S +++ b/arch/x86/kernel/mcount_64.S @@ -54,7 +54,15 @@ * be saved in the locations that pt_regs has them in. */ -/* @added: the amount of stack added before calling this */ +/* + * @added: the amount of stack added before calling this + * + * After this is called, the following registers contain: + * + * %rdi - holds the address that called the trampoline + * %rsi - holds the parent function (traced function's return address) + * %rdx - holds the original %rbp + */ .macro save_mcount_regs added=0 /* Always save the original rbp */ @@ -101,9 +109,24 @@ movq MCOUNT_REG_SIZE-8(%rsp), %rdx movq %rdx, RBP(%rsp) + /* Copy the parent address into %rsi (second parameter) */ +#ifdef CC_USING_FENTRY + movq MCOUNT_REG_SIZE+8+\added(%rsp), %rsi +#else + /* %rdx contains original %rbp */ + movq 8(%rdx), %rsi +#endif + /* Move RIP to its proper location */ movq MCOUNT_REG_SIZE+\added(%rsp), %rdi movq %rdi, RIP(%rsp) + + /* + * Now %rdi (the first parameter) has the return address of + * where ftrace_call returns. But the callbacks expect the + * the address of the call itself. + */ + subq $MCOUNT_INSN_SIZE, %rdi .endm .macro restore_mcount_regs @@ -122,28 +145,6 @@ .endm -/* skip is set if stack has been adjusted */ -.macro ftrace_caller_setup trace_label added=0 - save_mcount_regs \added - - /* Save this location */ -GLOBAL(\trace_label) - /* Load the ftrace_ops into the 3rd parameter */ - movq function_trace_op(%rip), %rdx - - /* %rdi already has %rip from the save_mcount_regs macro */ - subq $MCOUNT_INSN_SIZE, %rdi - /* Load the parent_ip into the second parameter */ -#ifdef CC_USING_FENTRY - movq MCOUNT_REG_SIZE+8+\added(%rsp), %rsi -#else - /* Need to grab the original %rbp */ - movq RBP(%rsp), %rsi - /* Now parent address is 8 above original %rbp */ - movq 8(%rsi), %rsi -#endif -.endm - #ifdef CONFIG_DYNAMIC_FTRACE ENTRY(function_hook) @@ -151,7 +152,13 @@ ENTRY(function_hook) END(function_hook) ENTRY(ftrace_caller) - ftrace_caller_setup ftrace_caller_op_ptr + /* save_mcount_regs fills in first two parameters */ + save_mcount_regs + +GLOBAL(ftrace_caller_op_ptr) + /* Load the ftrace_ops into the 3rd parameter */ + movq function_trace_op(%rip), %rdx + /* regs go into 4th parameter (but make it NULL) */ movq $0, %rcx @@ -182,7 +189,12 @@ ENTRY(ftrace_regs_caller) pushfq /* added 8 bytes to save flags */ - ftrace_caller_setup ftrace_regs_caller_op_ptr 8 + save_mcount_regs 8 + /* save_mcount_regs fills in first two parameters */ + +GLOBAL(ftrace_regs_caller_op_ptr) + /* Load the ftrace_ops into the 3rd parameter */ + movq function_trace_op(%rip), %rdx /* Save the rest of pt_regs */ movq %r15, R15(%rsp) @@ -263,7 +275,8 @@ GLOBAL(ftrace_stub) retq trace: - ftrace_caller_setup ftrace_caller_op_ptr + /* save_mcount_regs fills in first two parameters */ + save_mcount_regs call *ftrace_trace_function @@ -276,16 +289,16 @@ END(function_hook) #ifdef CONFIG_FUNCTION_GRAPH_TRACER ENTRY(ftrace_graph_caller) + /* Saves rbp into %rdx */ save_mcount_regs #ifdef CC_USING_FENTRY leaq MCOUNT_REG_SIZE+8(%rsp), %rdi movq $0, %rdx /* No framepointers needed */ #else - /* Need to grab the original %rbp */ - movq RBP(%rsp), %rdx - /* Now parent address is 8 above original %rbp */ + /* Save address of the return address of traced function */ leaq 8(%rdx), %rdi + /* ftrace does sanity checks against frame pointers */ movq (%rdx), %rdx #endif movq RIP(%rsp), %rsi |