tests/pt_regs_summary

   1 The semantic patch that does transformation first checks that
   2 linux/interrupt.h is included.  This header file specifies the type of
   3 request_irq.  There are multiple definitions of request_irq and the
   4 ones in the following two files still expect a parameter with a
   5 pt_regs-typed parameter.  Nevertheless, these files also include
   6 linux/interrupt.h, and so it seems that the definitions should be changed
   7 accordingly.
   8
   9 arch/h8300/platform/h8s/ints.c
  10 arch/arm26/kernel/irq.c
  11
  12 The semantic patch then identifies an interrupt handler function as
  13 one that is passed to request_irq, checks that the definition of this
  14 function is static (so we don't have to worry about calls to it from other
  15 files), updates its parameter list if there are no references to its regs
  16 parameter, updates any calls to it where the last argument is NULL, and
  17 inserts a warning message in any calls that have a non-NULL argument.  The
  18 purpose of the warning, rather than just dropping the argument, is that
  19 dropping the argument may cause some variables to no longer be used, and
  20 thus other changes might be useful.  However, in the files that trigger the
  21 collateral evolution there is never a direct call to the interrupt handling
  22 function, either with NULL or some other value as the final argument.
  23
  24
  25 The sgrep semantic patch detects the negation of the above: cases where
  26 either linux/interrupt.h is not included, or the interrupt handling
  27 function is not static, or the interrupt handling function uses its
  28 pt_regs-typed parameter.
  29
  30
  31 Files that are transformed:
  32 --- /home/julia/linux-2.6/arch/cris/arch-v10/drivers/gpio.c
  33 --- /home/julia/linux-2.6/arch/cris/arch-v10/kernel/fasttimer.c
  34 --- /home/julia/linux-2.6/arch/cris/arch-v32/drivers/cryptocop.c
  35 --- /home/julia/linux-2.6/arch/cris/arch-v32/drivers/gpio.c
  36 --- /home/julia/linux-2.6/arch/cris/arch-v32/drivers/sync_serial.c
  37 --- /home/julia/linux-2.6/arch/cris/arch-v32/kernel/fasttimer.c
  38     In all of the above, the transformation applies straightforwardly.  The
  39     interrupt handling function is static and it does not use its
  40     pt_regs-typed parameter.
  41
  42 --- /home/julia/linux-2.6/arch/cris/kernel/irq.c
  43     In this file the change is to remove the pt_regs-typed argument from
  44     __do_IRQ.  The enclosing function now has no need for the pt_regs-typed
  45     parameter, but we have not constructed the semantic patch to transform
  46     it and its callers.  Indeed, its callers appear never to be called
  47     themselves.
  48
  49 --- /home/julia/linux-2.6/arch/v850/kernel/gbus_int.c
  50     In this file the interrupt handling function calls handle_irq with its
  51     pt_regs-typed argument.  But handle_irq doesn't need this argument, as
  52     noted below.
  53
  54 --- /home/julia/linux-2.6/arch/v850/kernel/irq.c
  55     This file contains the definition of handle_irq.  It passes its
  56     pt_regs-typed argument to the function __do_IRQ.  But __do_IRQ no
  57     longer wants a pt_regs-typed argument either.  And so we can remove it
  58     from both the call and the parameter list, enabling the transformation
  59     in gbus_int.c and rte_me2_cb.c.
  60     PROBLEM: The .h file should have been updated as well, but this does
  61     not seem to have been done.
  62
  63 --- /home/julia/linux-2.6/arch/v850/kernel/rte_me2_cb.c
  64     In this file the interrupt handling function calls handle_irq with its
  65     pt_regs-typed argument.  But handle_irq doesn't need this argument, as
  66     noted above.
  67
  68 --- /home/julia/linux-2.6/drivers/spi/au1550_spi.c
  69     This file was added to the Linux kernel source tree quite recently:
  70     commit 63bd23591e6c3891d34e4c6dba7c6aa41b05caad
  71     Author: Jan Nikitenko <jan.nikitenko@gmail.com>
  72     Date:   Tue May 8 00:32:25 2007 -0700
  73
  74
  75
  76 Other cases, noted by sgrep:
  77 --- /home/julia/linux-2.6/arch/cris/arch-v32/kernel/arbiter.c
  78     In this case, the transformation should apply, but the pt_regs-typed
  79     parameter is used in what appears to be debugging code, which has to be
  80     changed by hand.
  81
  82 --- /home/julia/linux-2.6/arch/m68knommu/kernel/comempci.c
  83     In this case, the interrupt handler has the wrong signature, as it
  84     returns void rather than irqreturn_t.  Perhaps this file is dead code.
  85
  86 --- /home/julia/linux-2.6/arch/blackfin/oprofile/timer_int.c
  87     In this case, the file doesn't (directly) include linux/interrupt.h.
  88     It is not clear what definition of request_irq is being used and thus
  89     what type is expected for the interrupt handling function