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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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08d636b6d4
This method changes x86 to add a breakpoint to the mcount locations instead of calling stop machine. Now that iret can be handled by NMIs, we perform the following to update code: 1) Add a breakpoint to all locations that will be modified 2) Sync all cores 3) Update all locations to be either a nop or call (except breakpoint op) 4) Sync all cores 5) Remove the breakpoint with the new code. 6) Sync all cores [ Added updates that Masami suggested: Use unlikely(modifying_ftrace_code) in int3 trap to keep kprobes efficient. Don't use NOTIFY_* in ftrace handler in int3 as it is not a notifier. ] Cc: H. Peter Anvin <hpa@zytor.com> Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
61 lines
1.2 KiB
C
61 lines
1.2 KiB
C
#ifndef _ASM_X86_FTRACE_H
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#define _ASM_X86_FTRACE_H
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#ifdef __ASSEMBLY__
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.macro MCOUNT_SAVE_FRAME
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/* taken from glibc */
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subq $0x38, %rsp
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movq %rax, (%rsp)
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movq %rcx, 8(%rsp)
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movq %rdx, 16(%rsp)
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movq %rsi, 24(%rsp)
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movq %rdi, 32(%rsp)
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movq %r8, 40(%rsp)
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movq %r9, 48(%rsp)
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.endm
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.macro MCOUNT_RESTORE_FRAME
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movq 48(%rsp), %r9
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movq 40(%rsp), %r8
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movq 32(%rsp), %rdi
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movq 24(%rsp), %rsi
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movq 16(%rsp), %rdx
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movq 8(%rsp), %rcx
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movq (%rsp), %rax
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addq $0x38, %rsp
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.endm
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#endif
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#ifdef CONFIG_FUNCTION_TRACER
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#define MCOUNT_ADDR ((long)(mcount))
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#define MCOUNT_INSN_SIZE 5 /* sizeof mcount call */
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#ifndef __ASSEMBLY__
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extern void mcount(void);
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extern int modifying_ftrace_code;
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static inline unsigned long ftrace_call_adjust(unsigned long addr)
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{
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/*
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* addr is the address of the mcount call instruction.
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* recordmcount does the necessary offset calculation.
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*/
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return addr;
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}
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#ifdef CONFIG_DYNAMIC_FTRACE
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struct dyn_arch_ftrace {
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/* No extra data needed for x86 */
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};
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int ftrace_int3_handler(struct pt_regs *regs);
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#endif /* CONFIG_DYNAMIC_FTRACE */
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#endif /* __ASSEMBLY__ */
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#endif /* CONFIG_FUNCTION_TRACER */
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#endif /* _ASM_X86_FTRACE_H */
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