ARM unaligned MMIO access with attribute((packed))
rabin at rab.in
Wed Apr 27 10:06:00 EDT 2011
On Wed, Apr 27, 2011 at 00:21, Alan Stern <stern at rowland.harvard.edu> wrote:
> On Tue, 26 Apr 2011, Rabin Vincent wrote:
>> In my case it's this writel() in ehci-hub.c that gets chopped into
>> /* force reset to complete */
>> ehci_writel(ehci, temp & ~(PORT_RWC_BITS | PORT_RESET),
> Why would that get messed up? The status_reg variable doesn't have any
> __atribute__((packed)) associated with it.
The initialization of status_reg is:
u32 __iomem *status_reg
= &ehci->regs->port_status[(wIndex & 0xff) - 1];
where ehci->regs is a pointer to the packed struct ehci_regs. So, this
is the same problem of casting pointers to stricter alignment.
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