Re: [PATCH] lib: vsprintf: Add %pa format specifier for phys_addr_t types

Andy Shevchenko
2013-01-22T07:29:45Z

On Mon, 2013-01-21 at 21:47 -0800, Stepan Moskovchenko wrote:
> Add the %pa format specifier for printing a phys_addr_t
> type, since the physical address size on some platforms
> can vary based on build options, regardless of the native
> integer type.
>
> Signed-off-by: Stepan Moskovchenko <stepanm@codeaurora.org>
> ---
> Documentation/printk-formats.txt | 13 ++++++++++---
> lib/vsprintf.c | 7 +++++++
> 2 files changed, 17 insertions(+), 3 deletions(-)
>
> diff --git a/Documentation/printk-formats.txt b/Documentation/printk-formats.txt
> index 8ffb274..dbc977b 100644
> --- a/Documentation/printk-formats.txt
> +++ b/Documentation/printk-formats.txt
> @@ -53,6 +53,13 @@ Struct Resources:
> For printing struct resources. The 'R' and 'r' specifiers result in a
> printed resource with ('R') or without ('r') a decoded flags member.
>
> +Physical addresses:
> +
> + %pa 0x01234567 or 0x0123456789abcdef
> +
> + For printing a phys_addr_t type, which can vary based on build options,
> + regardless of the width of the CPU data path. Passed by reference.
> +
> Raw buffer as a hex string:
> %*ph 00 01 02 ... 3f
> %*phC 00:01:02: ... :3f
> @@ -150,9 +157,9 @@ s64 SHOULD be printed with %lld/%llx, (long long):
> printk("%lld", (long long)s64_var);
>
> If <type> is dependent on a config option for its size (e.g., sector_t,
> -blkcnt_t, phys_addr_t, resource_size_t) or is architecture-dependent
> -for its size (e.g., tcflag_t), use a format specifier of its largest
> -possible type and explicitly cast to it. Example:
> +blkcnt_t, resource_size_t) or is architecture-dependent for its size (e.g.,

resource_size_t is a typedef of phys_addr_t.

Probably you should mention that your change related to the phys_addr_t
*and* derivatives.

> +tcflag_t), use a format specifier of its largest possible type and explicitly
> +cast to it. Example:
>
> printk("test: sector number/total blocks: %llu/%llu\n",
> (unsigned long long)sector, (unsigned long long)blockcount);
> diff --git a/lib/vsprintf.c b/lib/vsprintf.c
> index 39c99fe..9b02a71 100644
> --- a/lib/vsprintf.c
> +++ b/lib/vsprintf.c
> @@ -1022,6 +1022,7 @@ int kptr_restrict __read_mostly;
> * N no separator
> * The maximum supported length is 64 bytes of the input. Consider
> * to use print_hex_dump() for the larger input.
> + * - 'a' For a phys_addr_t type (passed by reference)
> *
> * Note: The difference between 'S' and 'F' is that on ia64 and ppc64
> * function pointers are really function descriptors, which contain a
> @@ -1112,6 +1113,12 @@ char *pointer(const char *fmt, char *buf, char *end, void *ptr,
> return netdev_feature_string(buf, end, ptr, spec);
> }
> break;
> + case 'a':
> + spec.flags |= SPECIAL | SMALL | ZEROPAD;
> + spec.field_width = sizeof(phys_addr_t) * 2;
> + spec.base = 16;
> + return number(buf, end,
> + (unsigned long long) *((phys_addr_t *)ptr), spec);
> }
> spec.flags |= SMALL;
> if (spec.field_width == -1) {
> --
> The Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
> hosted by The Linux Foundation
>

--
Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Intel Finland Oy