imx6 and keystone PCIe abort handling

Hi folks,

Why are ks_pcie_fault() and imx6q_pcie_abort_handler() different? I think they're doing the same thing, and the "instr & 0x0e100090" part is the same, but only imx6 has the "instr & 0x0c100000" part. And the return values are different in some cases.

Could/should these be shared somehow? They're both under #ifdef CONFIG_ARM, so maybe it could be provided by arch/arm?

static int ks_pcie_fault(unsigned long addr, unsigned int fsr,
struct pt_regs *regs)

  {
	  unsigned long instr = *(unsigned long *) instruction_pointer(regs);

	  if ((instr & 0x0e100090) == 0x00100090) {
		  int reg = (instr >> 12) & 15;

		  regs->uregs[reg] = -1;
		  regs->ARM_pc += 4;
	  }

	  return 0;

}

static int imx6q_pcie_abort_handler(unsigned long addr,
unsigned int fsr, struct pt_regs *regs)

  {
	  unsigned long pc = instruction_pointer(regs);
	  unsigned long instr = *(unsigned long *)pc;
	  int reg = (instr >> 12) & 15;

	  /*
	   * If the instruction being executed was a read,
	   * make it look like it read all-ones.
	   */
	  if ((instr & 0x0c100000) == 0x04100000) {
		  unsigned long val;

		  if (instr & 0x00400000)
			  val = 255;
		  else
			  val = -1;

		  regs->uregs[reg] = val;
		  regs->ARM_pc += 4;
		  return 0;
	  }

	  if ((instr & 0x0e100090) == 0x00100090) {
		  regs->uregs[reg] = -1;
		  regs->ARM_pc += 4;
		  return 0;
	  }

	  return 1;

}

Here's the opcodes for the three different types of loads that would be interesting.

   0:   e5910000        ldr     r0, [r1] ; 32-bit
   4:   e5d10000        ldrb    r0, [r1] ; 8-bit
   8:   e1d100b0        ldrh    r0, [r1] ; 16-bit

So, (instr & 0x0e100090) == 0x00100090 is trie for the ldrh case. (instr & 0x0c100000) == 0x04100000 is true for the ldr and ldrb case.

So, the keystone version only traps ldrh instructions, whereas the imx6 traps them all.

RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTC broadband for 0.8mile line in suburbia: sync at 12.1Mbps down 622kbps up
According to speedtest.net: 11.9Mbps down 500kbps up