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Re: [RFC][PATCH] Kprobes robust fault handling for i386
prasanna wrote:
> [...] IIUC you are planning on setjmp/longjmp() in systemtap
> generated handlers themselves ?
That was one idea, yeah.
> This can be achieved even without the robust fault handling code.
Except I can't find any general setjmp/longjmp implementation in the
kernel.
> [...]
> if ((setjmp(systemtap_jmp_buffer)) != 0) {
> <cleanup code>
> }
> copy_from_user_inatomic(.....);
(The systemtap-emitted setjmp would likely be in the probe prologue
boilerplate, not associated with copy_from_user so closely.)
> [...]
> systemtap_faulthandler(....)
> regs->eip = (unsigned long) systemtap_fault_trampoline;
> return 1; /*kprobe handler need not do anything else */
"instruction_register(regs)" instead "regs->eip" for portability,
right?
> [...]
> systemtap_fault_trampoline(void)
> longjmp(systemtap_jmp_buffer);
> return;
That sounds simple enough (assuming the availability of longjmp).
- FChE