Hi,
On 08/06/2021 17:50, Marek Szyprowski wrote:
> Hi
>
> On 08.06.2021 17:33, Neil Armstrong wrote:
>> It has been reported that usage of memcpy() to/from an iomem mapping is invalid,
>> and and recent arm64 memcpy update [1] triggers a memory abort when dram-access-quirk
>> is used on the G12A/G12B platforms.
>>
>> This adds a local sg_copy_to_buffer which makes usage of io versions of memcpy
>> when dram-access-quirk is enabled.
>>
>> Fixes: acdc8e71d9bb ("mmc: meson-gx: add dram-access-quirk")
>> Reported-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
>> Suggested-by: Mark Rutland <mark.rutland@xxxxxxx>
>> Signed-off-by: Neil Armstrong <narmstrong@xxxxxxxxxxxx>
>>
>> [1] 285133040e6c ("arm64: Import latest memcpy()/memmove() implementation")
>>
>> Signed-off-by: Neil Armstrong <narmstrong@xxxxxxxxxxxx>
>> ---
>> Hi Ulf, Marek, Mark,
>>
>> I haven't tested the patch yet, but should fix issue reported at [2].
>
> Works fine here and fixed the issue.
>
> Tested-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
Thanks, I'll need to rework to pass an __iomem pointer to memcpy_to/fromio so sparse doesn't scream anymore.
Neil
>
>> Neil
>>
>> [2] https://lore.kernel.org/r/acb244ad-0759-5a96-c659-5c23003d3dcd@xxxxxxxxxxx
>>
>> drivers/mmc/host/meson-gx-mmc.c | 48 ++++++++++++++++++++++++++++++---
>> 1 file changed, 44 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/mmc/host/meson-gx-mmc.c b/drivers/mmc/host/meson-gx-mmc.c
>> index b8b771b643cc..89ff6038092d 100644
>> --- a/drivers/mmc/host/meson-gx-mmc.c
>> +++ b/drivers/mmc/host/meson-gx-mmc.c
>> @@ -742,6 +742,48 @@ static void meson_mmc_desc_chain_transfer(struct mmc_host *mmc, u32 cmd_cfg)
>> writel(start, host->regs + SD_EMMC_START);
>> }
>>
>> +/* local sg copy to buffer version with _to/fromio usage for dram_access_quirk */
>> +static void meson_mmc_copy_buffer(struct meson_host *host, struct mmc_data *data,
>> + size_t buflen, bool to_buffer)
>> +{
>> + unsigned int sg_flags = SG_MITER_ATOMIC;
>> + struct scatterlist *sgl = data->sg;
>> + unsigned int nents = data->sg_len;
>> + struct sg_mapping_iter miter;
>> + void *buf = host->bounce_buf;
>> + unsigned int offset = 0;
>> +
>> + if (to_buffer)
>> + sg_flags |= SG_MITER_FROM_SG;
>> + else
>> + sg_flags |= SG_MITER_TO_SG;
>> +
>> + sg_miter_start(&miter, sgl, nents, sg_flags);
>> +
>> + while ((offset < buflen) && sg_miter_next(&miter)) {
>> + unsigned int len;
>> +
>> + len = min(miter.length, buflen - offset);
>> +
>> + /* When dram_access_quirk, the bounce buffer is a iomem mapping */
>> + if (host->dram_access_quirk) {
>> + if (to_buffer)
>> + memcpy_toio(buf + offset, miter.addr, len);
>> + else
>> + memcpy_fromio(miter.addr, buf + offset, len);
>> + } else {
>> + if (to_buffer)
>> + memcpy(buf + offset, miter.addr, len);
>> + else
>> + memcpy(miter.addr, buf + offset, len);
>> + }
>> +
>> + offset += len;
>> + }
>> +
>> + sg_miter_stop(&miter);
>> +}
>> +
>> static void meson_mmc_start_cmd(struct mmc_host *mmc, struct mmc_command *cmd)
>> {
>> struct meson_host *host = mmc_priv(mmc);
>> @@ -785,8 +827,7 @@ static void meson_mmc_start_cmd(struct mmc_host *mmc, struct mmc_command *cmd)
>> if (data->flags & MMC_DATA_WRITE) {
>> cmd_cfg |= CMD_CFG_DATA_WR;
>> WARN_ON(xfer_bytes > host->bounce_buf_size);
>> - sg_copy_to_buffer(data->sg, data->sg_len,
>> - host->bounce_buf, xfer_bytes);
>> + meson_mmc_copy_buffer(host, data, xfer_bytes, true);
>> dma_wmb();
>> }
>>
>> @@ -955,8 +996,7 @@ static irqreturn_t meson_mmc_irq_thread(int irq, void *dev_id)
>> if (meson_mmc_bounce_buf_read(data)) {
>> xfer_bytes = data->blksz * data->blocks;
>> WARN_ON(xfer_bytes > host->bounce_buf_size);
>> - sg_copy_from_buffer(data->sg, data->sg_len,
>> - host->bounce_buf, xfer_bytes);
>> + meson_mmc_copy_buffer(host, data, xfer_bytes, false);
>> }
>>
>> next_cmd = meson_mmc_get_next_command(cmd);
>
> Best regards
>
