Hi Seungwon

This patch didn't build..plz check.

Best Regards,
Jaehoon Chung

On 02/06/2012 04:57 PM, Seungwon Jeon wrote:

> Current PIO mode makes a kernel crash with CONFIG_HIGHMEM.
> High memory pages have a NULL from sg_virt(sg).
> This patch fixes the following problem.
> 
> Unable to handle kernel NULL pointer dereference at virtual address 00000000
> pgd = c0004000
> [00000000] *pgd=00000000
> Internal error: Oops: 817 [#1] PREEMPT SMP
> Modules linked in:
> CPU: 0    Not tainted  (3.0.15-01423-gdbf465f #589)
> PC is at dw_mci_pull_data32+0x4c/0x9c
> LR is at dw_mci_read_data_pio+0x54/0x1f0
> pc : [<c0358824>]    lr : [<c035988c>]    psr: 20000193
> sp : c0619d48  ip : c0619d70  fp : c0619d6c
> r10: 00000000  r9 : 00000002  r8 : 00001000
> r7 : 00000200  r6 : 00000000  r5 : e1dd3100  r4 : 00000000
> r3 : 65622023  r2 : 0000007f  r1 : eeb96000  r0 : e1dd3100
> Flags: nzCv  IRQs off  FIQs on  Mode SVC_32  ISA ARM  Segment
> kernel
> Control: 10c5387d  Table: 61e2004a  DAC: 00000015
> Process swapper (pid: 0, stack limit = 0xc06182f0)
> Stack: (0xc0619d48 to 0xc061a000)
> 9d40:                   e1dd3100 e1a4f000 00000000 e1dd3100 e1a4f000 00000200
> 9d60: c0619da4 c0619d70 c035988c c03587e4 c0619d9c e18158f4 e1dd3100 e1dd3100
> 9d80: 00000020 00000000 00000000 00000020 c06e8a84 00000000 c0619e04 c0619da8
> 9da0: c0359b24 c0359844 e18158f4 e1dd3164 e1dd3168 e1dd3150 3d02fc79 e1dd3154
> 9dc0: e1dd3178 00000000 00000020 00000000 e1dd3150 00000000 c10dd7e8 e1a84900
> 9de0: c061e7cc 00000000 00000000 0000008d c06e8a84 c061e780 c0619e4c c0619e08
> 9e00: c00c4738 c0359a34 3d02fc79 00000000 c0619e4c c05a1698 c05a1670 c05a165c
> 9e20: c04de8b0 c061e780 c061e7cc e1a84900 ffffed68 0000008d c0618000 00000000
> 9e40: c0619e6c c0619e50 c00c48b4 c00c46c8 c061e780 c00423ac c061e7cc ffffed68
> 9e60: c0619e8c c0619e70 c00c7358 c00c487c 0000008d ffffee38 c0618000 ffffed68
> 9e80: c0619ea4 c0619e90 c00c4258 c00c72b0 c00423ac ffffee38 c0619ecc c0619ea8
> 9ea0: c004241c c00c4234 ffffffff f8810000 0000006d 00000002 00000001 7fffffff
> 9ec0: c0619f44 c0619ed0 c0048bc0 c00423c4 220ae7a9 00000000 386f0d30 0005d3a4
> 9ee0: c00423ac c10dd0b8 c06f2cd8 c0618000 c0594778 c003a674 7fffffff c0619f44
> 9f00: 386f0d30 c0619f18 c00a6f94 c005be3c 80000013 ffffffff 386f0d30 0005d3a4
> 9f20: 386f0d30 0005d2d1 c10dd0a8 c10dd0b8 c06f2cd8 c0618000 c0619f74 c0619f48
> 9f40: c0345858 c005be00 c00a2440 c0618000 c0618000 c00410d8 c06c1944 c00410fc
> 9f60: c0594778 c003a674 c0619f9c c0619f78 c004a7e8 c03457b4 c0618000 c06c18f8
> 9f80: 00000000 c0039c70 c06c18d4 c003a674 c0619fb4 c0619fa0 c04ceafc c004a714
> 9fa0: c06287b4 c06c18f8 c0619ff4 c0619fb8 c0008b68 c04cea68 c0008578 00000000
> 9fc0: 00000000 c003a674 00000000 10c5387d c0628658 c003aa78 c062f1c4 4000406a
> 9fe0: 413fc090 00000000 00000000 c0619ff8 40008044 c0008858 00000000 00000000
> Backtrace:
> [<c03587d8>] (dw_mci_pull_data32+0x0/0x9c) from [<c035988c>] 
> (dw_mci_read_data_pio+0x54/0x1f0)
>  r6:00000200 r5:e1a4f000 r4:e1dd3100
>  [<c0359838>] (dw_mci_read_data_pio+0x0/0x1f0) from [<c0359b24>] 
> (dw_mci_interrupt+0xfc/0x4a4)
> [<c0359a28>] (dw_mci_interrupt+0x0/0x4a4) from [<c00c4738>] 
> (handle_irq_event_percpu+0x7c/0x1b4)
> [<c00c46bc>] (handle_irq_event_percpu+0x0/0x1b4) from [<c00c48b4>] 
> (handle_irq_event+0x44/0x64)
> [<c00c4870>] (handle_irq_event+0x0/0x64) from [<c00c7358>] 
> (handle_fasteoi_irq+0xb4/0x124)
>  r7:ffffed68 r6:c061e7cc r5:c00423ac r4:c061e780
>  [<c00c72a4>] (handle_fasteoi_irq+0x0/0x124) from [<c00c4258>] 
> (generic_handle_irq+0x30/0x38)
>  r7:ffffed68 r6:c0618000 r5:ffffee38 r4:0000008d
>  [<c00c4228>] (generic_handle_irq+0x0/0x38) from [<c004241c>] 
> (asm_do_IRQ+0x64/0xe0)
>  r5:ffffee38 r4:c00423ac
>  [<c00423b8>] (asm_do_IRQ+0x0/0xe0) from [<c0048bc0>] (__irq_svc+0x80/0x14c)
> Exception stack(0xc0619ed0 to 0xc0619f18)
> 
> Signed-off-by: Seungwon Jeon <[email protected]>
> ---
>  drivers/mmc/host/dw_mmc.c  |  143 
> +++++++++++++++++++++++---------------------
>  include/linux/mmc/dw_mmc.h |    4 +-
>  2 files changed, 77 insertions(+), 70 deletions(-)
> 
> diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
> index dee839e..22aba57 100644
> --- a/drivers/mmc/host/dw_mmc.c
> +++ b/drivers/mmc/host/dw_mmc.c
> @@ -575,8 +575,14 @@ static void dw_mci_submit_data(struct dw_mci *host, 
> struct mmc_data *data)
>               host->dir_status = DW_MCI_SEND_STATUS;
>  
>       if (dw_mci_submit_data_dma(host, data)) {
> +             int flags = SG_MITER_ATOMIC;
> +             if (host->data->flags & MMC_DATA_READ)
> +                     flags |= SG_MITER_TO_SG;
> +             else
> +                     flags |= SG_MITER_FROM_SG;
> +
> +             sg_miter_start(&host->sg_miter, data->sg, data->sg_len, flags);
>               host->sg = data->sg;
> -             host->pio_offset = 0;
>               host->part_buf_start = 0;
>               host->part_buf_count = 0;
>  
> @@ -1047,6 +1053,7 @@ static void dw_mci_tasklet_func(unsigned long priv)
>                                * generates a block interrupt, hence setting
>                                * the scatter-gather pointer to NULL.
>                                */
> +                             sg_miter_stop(&host->sg_miter);
>                               host->sg = NULL;
>                               ctrl = mci_readl(host, CTRL);
>                               ctrl |= SDMMC_CTRL_FIFO_RESET;
> @@ -1386,54 +1393,44 @@ static void dw_mci_pull_data(struct dw_mci *host, 
> void *buf, int cnt)
>  
>  static void dw_mci_read_data_pio(struct dw_mci *host)
>  {
> -     struct scatterlist *sg = host->sg;
> -     void *buf = sg_virt(sg);
> -     unsigned int offset = host->pio_offset;
> +     struct sg_mapping_iter *sg_miter = &host->sg_miter;
> +     void *buf;
> +     unsigned int offset;
>       struct mmc_data *data = host->data;
>       int shift = host->data_shift;
>       u32 status;
>       unsigned int nbytes = 0, len;
> +     unsigned int remain, fcnt;
>  
>       do {
> -             len = host->part_buf_count +
> -                     (SDMMC_GET_FCNT(mci_readl(host, STATUS)) << shift);
> -             if (offset + len <= sg->length) {
> +             if (!sg_miter_next(sg_miter))
> +                     goto done;
> +
> +             host->sg = sg_miter->__sg;
> +             buf = sg_miter->addr;
> +             remain = sg_miter->length;
> +             offset = 0;
> +
> +             do {
> +                     fcnt = (SDMMC_GET_FCNT(mci_readl(host, STATUS))
> +                                     << shift) + host->part_buf_count;
> +                     len = min(remain, fcnt);
> +                     if (!len)
> +                             break;
>                       dw_mci_pull_data(host, (void *)(buf + offset), len);
> -
>                       offset += len;
>                       nbytes += len;
> -
> -                     if (offset == sg->length) {
> -                             flush_dcache_page(sg_page(sg));
> -                             host->sg = sg = sg_next(sg);
> -                             if (!sg)
> -                                     goto done;
> -
> -                             offset = 0;
> -                             buf = sg_virt(sg);
> -                     }
> -             } else {
> -                     unsigned int remaining = sg->length - offset;
> -                     dw_mci_pull_data(host, (void *)(buf + offset),
> -                                      remaining);
> -                     nbytes += remaining;
> -
> -                     flush_dcache_page(sg_page(sg));
> -                     host->sg = sg = sg_next(sg);
> -                     if (!sg)
> -                             goto done;
> -
> -                     offset = len - remaining;
> -                     buf = sg_virt(sg);
> -                     dw_mci_pull_data(host, buf, offset);
> -                     nbytes += offset;
> -             }
> +                     remain -= len;
> +             } while (remain);
> +             sg_miter->consumed = offset;
>  
>               status = mci_readl(host, MINTSTS);
>               mci_writel(host, RINTSTS, SDMMC_INT_RXDR);
>               if (status & DW_MCI_DATA_ERROR_FLAGS) {
>                       host->data_status = status;
>                       data->bytes_xfered += nbytes;
> +                     sg_miter_stop(sg_miter);
> +                     host->sg = NULL;
>                       smp_wmb();
>  
>                       set_bit(EVENT_DATA_ERROR, &host->pending_events);
> @@ -1442,65 +1439,66 @@ static void dw_mci_read_data_pio(struct dw_mci *host)
>                       return;
>               }
>       } while (status & SDMMC_INT_RXDR); /*if the RXDR is ready read again*/
> -     host->pio_offset = offset;
>       data->bytes_xfered += nbytes;
> +
> +     if (!remain) {
> +             if (!sg_miter_next(sg_miter))
> +                     goto done;
> +             sg_miter->consumed = 0;
> +     }
> +     sg_miter_stop(sg_miter);
>       return;
>  
>  done:
>       data->bytes_xfered += nbytes;
> +     sg_miter_stop(sg_miter);
> +     host->sg = NULL;
>       smp_wmb();
>       set_bit(EVENT_XFER_COMPLETE, &host->pending_events);
>  }
>  
>  static void dw_mci_write_data_pio(struct dw_mci *host)
>  {
> -     struct scatterlist *sg = host->sg;
> -     void *buf = sg_virt(sg);
> -     unsigned int offset = host->pio_offset;
> +     struct sg_mapping_iter *sg_miter = &host->sg_miter;
> +     void *buf;
> +     unsigned int offset;
>       struct mmc_data *data = host->data;
>       int shift = host->data_shift;
>       u32 status;
>       unsigned int nbytes = 0, len;
> +     unsigned int fifo_depth = host->fifo_depth;
> +     unsigned int remain, fcnt;
>  
>       do {
> -             len = ((host->fifo_depth -
> -                     SDMMC_GET_FCNT(mci_readl(host, STATUS))) << shift)
> -                     - host->part_buf_count;
> -             if (offset + len <= sg->length) {
> +             if (!sg_miter_next(sg_miter))
> +                     goto done;
> +
> +             host->sg = sg_miter->__sg;
> +             buf = sg_miter->addr;
> +             remain = sg_miter->length;
> +             offset = 0;
> +
> +             do {
> +                     fcnt = ((fifo_depth -
> +                              SDMMC_GET_FCNT(mci_readl(host, STATUS)))
> +                                     << shift) - host->part_buf_count;
> +                     len = min(remain, fcnt);
> +                     if (!len)
> +                             break;
>                       host->push_data(host, (void *)(buf + offset), len);
> -
>                       offset += len;
>                       nbytes += len;
> -                     if (offset == sg->length) {
> -                             host->sg = sg = sg_next(sg);
> -                             if (!sg)
> -                                     goto done;
> -
> -                             offset = 0;
> -                             buf = sg_virt(sg);
> -                     }
> -             } else {
> -                     unsigned int remaining = sg->length - offset;
> -
> -                     host->push_data(host, (void *)(buf + offset),
> -                                     remaining);
> -                     nbytes += remaining;
> -
> -                     host->sg = sg = sg_next(sg);
> -                     if (!sg)
> -                             goto done;
> -
> -                     offset = len - remaining;
> -                     buf = sg_virt(sg);
> -                     host->push_data(host, (void *)buf, offset);
> -                     nbytes += offset;
> -             }
> +                     remain -= len;
> +             } while (remain);
> +             sg_miter->consumed = offset;
>  
>               status = mci_readl(host, MINTSTS);
>               mci_writel(host, RINTSTS, SDMMC_INT_TXDR);
>               if (status & DW_MCI_DATA_ERROR_FLAGS) {
>                       host->data_status = status;
>                       data->bytes_xfered += nbytes;
> +                     sg_miter_stop(sg_miter);
> +                     host->sg = NULL;
>  
>                       smp_wmb();
>  
> @@ -1510,12 +1508,20 @@ static void dw_mci_write_data_pio(struct dw_mci *host)
>                       return;
>               }
>       } while (status & SDMMC_INT_TXDR); /* if TXDR write again */
> -     host->pio_offset = offset;
>       data->bytes_xfered += nbytes;
> +
> +     if (!remain) {
> +             if (!sg_miter_next(sg_miter))
> +                     goto done;
> +             sg_miter->consumed = 0;
> +     }
> +     sg_miter_stop(sg_miter);
>       return;
>  
>  done:
>       data->bytes_xfered += nbytes;
> +     sg_miter_stop(sg_miter);
> +     host->sg = NULL;
>       smp_wmb();
>       set_bit(EVENT_XFER_COMPLETE, &host->pending_events);
>  }
> @@ -1718,6 +1724,7 @@ static void dw_mci_work_routine_card(struct work_struct 
> *work)
>                                * block interrupt, hence setting the
>                                * scatter-gather pointer to NULL.
>                                */
> +                             sg_miter_stop(&host->sg_miter);
>                               host->sg = NULL;
>  
>                               ctrl = mci_readl(host, CTRL);
> diff --git a/include/linux/mmc/dw_mmc.h b/include/linux/mmc/dw_mmc.h
> index b4c031d..64ccd05 100644
> --- a/include/linux/mmc/dw_mmc.h
> +++ b/include/linux/mmc/dw_mmc.h
> @@ -40,7 +40,7 @@ struct mmc_data;
>   * @lock: Spinlock protecting the queue and associated data.
>   * @regs: Pointer to MMIO registers.
>   * @sg: Scatterlist entry currently being processed by PIO code, if any.
> - * @pio_offset: Offset into the current scatterlist entry.
> + * @sg_miter: PIO mapping scatterlist iterator.
>   * @cur_slot: The slot which is currently using the controller.
>   * @mrq: The request currently being processed on @cur_slot,
>   *   or NULL if the controller is idle.
> @@ -117,7 +117,7 @@ struct dw_mci {
>       void __iomem            *regs;
>  
>       struct scatterlist      *sg;
> -     unsigned int            pio_offset;
> +     struct sg_mapping_iter  sg_miter;
>  
>       struct dw_mci_slot      *cur_slot;
>       struct mmc_request      *mrq;


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