4df3c9ec12
When enabling all-branch ftrace support (CONFIG_PROFILE_ALL_BRANCHES) the kernel gets really huge and some ftrace assembler functions like mcount can't reach the ftrace helper functions which are written in C. Avoid this problem of too distant branches by moving the ftrace C-helper functions into the .text.hot section which is put in front of the standard .text section by the linker. Signed-off-by: Helge Deller <deller@gmx.de>
89 lines
2.2 KiB
C
89 lines
2.2 KiB
C
/*
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* Code for tracing calls in Linux kernel.
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* Copyright (C) 2009-2016 Helge Deller <deller@gmx.de>
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*
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* based on code for x86 which is:
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* Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
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*
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* future possible enhancements:
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* - add CONFIG_DYNAMIC_FTRACE
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* - add CONFIG_STACK_TRACER
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*/
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#include <linux/init.h>
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#include <linux/ftrace.h>
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#include <asm/assembly.h>
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#include <asm/sections.h>
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#include <asm/ftrace.h>
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#define __hot __attribute__ ((__section__ (".text.hot")))
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#ifdef CONFIG_FUNCTION_GRAPH_TRACER
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/*
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* Hook the return address and push it in the stack of return addrs
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* in current thread info.
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*/
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static void __hot prepare_ftrace_return(unsigned long *parent,
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unsigned long self_addr)
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{
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unsigned long old;
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struct ftrace_graph_ent trace;
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extern int parisc_return_to_handler;
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if (unlikely(ftrace_graph_is_dead()))
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return;
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if (unlikely(atomic_read(¤t->tracing_graph_pause)))
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return;
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old = *parent;
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trace.func = self_addr;
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trace.depth = current->curr_ret_stack + 1;
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/* Only trace if the calling function expects to */
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if (!ftrace_graph_entry(&trace))
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return;
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if (ftrace_push_return_trace(old, self_addr, &trace.depth,
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0 ) == -EBUSY)
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return;
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/* activate parisc_return_to_handler() as return point */
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*parent = (unsigned long) &parisc_return_to_handler;
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}
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#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
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void notrace __hot ftrace_function_trampoline(unsigned long parent,
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unsigned long self_addr,
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unsigned long org_sp_gr3)
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{
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extern ftrace_func_t ftrace_trace_function; /* depends on CONFIG_DYNAMIC_FTRACE */
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extern int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace);
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if (ftrace_trace_function != ftrace_stub) {
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/* struct ftrace_ops *op, struct pt_regs *regs); */
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ftrace_trace_function(parent, self_addr, NULL, NULL);
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return;
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}
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#ifdef CONFIG_FUNCTION_GRAPH_TRACER
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if (ftrace_graph_return != (trace_func_graph_ret_t) ftrace_stub ||
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ftrace_graph_entry != ftrace_graph_entry_stub) {
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unsigned long *parent_rp;
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/* calculate pointer to %rp in stack */
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parent_rp = (unsigned long *) (org_sp_gr3 - RP_OFFSET);
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/* sanity check: parent_rp should hold parent */
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if (*parent_rp != parent)
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return;
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prepare_ftrace_return(parent_rp, self_addr);
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return;
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}
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#endif
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}
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