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SubjectRe: [PATCH] spi/xilinx: Fix access invalid memory on xilinx_spi_tx
From
Hi Ricardo,

On Fri, Jan 30, 2015 at 7:10 AM, Ricardo Ribalda Delgado
<ricardo.ribalda@gmail.com> wrote:
> On 1 and 2 bytes per word, the transfer of the 3 last bytes will access
> memory outside rx_ptr.
>
> Although this has not trigger any error on real hardware, we should
> better fix this.
>
> Fixes: 24ba5e593f391507 Remove rx_fn and tx_fn pointer
> Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
> ---
> drivers/spi/spi-xilinx.c | 17 ++++++++++++++++-
> 1 file changed, 16 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/spi/spi-xilinx.c b/drivers/spi/spi-xilinx.c
> index 2ca55f6..a1b664d 100644
> --- a/drivers/spi/spi-xilinx.c
> +++ b/drivers/spi/spi-xilinx.c
> @@ -97,11 +97,26 @@ struct xilinx_spi {
>
> static void xilinx_spi_tx(struct xilinx_spi *xspi)
> {
> + u32 data = 0;
> +
> if (!xspi->tx_ptr) {
> xspi->write_fn(0, xspi->regs + XSPI_TXD_OFFSET);
> return;
> }
> - xspi->write_fn(*(u32 *)(xspi->tx_ptr), xspi->regs + XSPI_TXD_OFFSET);
> +
> + switch (xspi->bytes_per_word) {
> + case 1:
> + data = *(u8 *)(xspi->rx_ptr);
> + break;
> + case 2:
> + data = *(u16 *)(xspi->rx_ptr);
> + break;
> + case 4:
> + data = *(u32 *)(xspi->rx_ptr);
> + break;
> + }
> +
> + xspi->write_fn(data, xspi->regs + XSPI_TXD_OFFSET);

Is this endian-safe?

> xspi->tx_ptr += xspi->bytes_per_word;
> }

Gr{oetje,eeting}s,

Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds


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