Re: [XEN v5] xen/arm: Use the correct format specifier

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Wed, 25 Jan 2023, Ayan Kumar Halder wrote:
> 1. One should use 'PRIpaddr' to display 'paddr_t' variables. However,
> while creating nodes in fdt, the address (if present in the node name)
> should be represented using 'PRIx64'. This is to be in conformance
> with the following rule present in https://elinux.org/Device_Tree_Linux
> 
> . node names
> "unit-address does not have leading zeros"
> 
> As 'PRIpaddr' introduces leading zeros, we cannot use it.
> 
> So, we have introduced a wrapper ie domain_fdt_begin_node() which will
> represent physical address using 'PRIx64'.
> 
> 2. One should use 'PRIx64' to display 'u64' in hex format. The current
> use of 'PRIpaddr' for printing PTE is buggy as this is not a physical
> address.
> 
> Signed-off-by: Ayan Kumar Halder <ayan.kumar.halder@xxxxxxx>


Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>

(I checked that Ayan also addressed Julien's latest comments.)


> ---
> Changes from -
> 
> v1 - 1. Moved the patch earlier.
> 2. Moved a part of change from "[XEN v1 8/9] xen/arm: Other adaptations 
> required to support 32bit paddr"
> into this patch.
> 
> v2 - 1. Use PRIx64 for appending addresses to fdt node names. This fixes the 
> CI failure.
> 
> v3 - 1. Added a comment on top of domain_fdt_begin_node().
> 2. Check for the return of snprintf() in domain_fdt_begin_node().
> 
> v4 - 1. Grammatical error fixes.
> 
>  xen/arch/arm/domain_build.c | 64 +++++++++++++++++++++++--------------
>  xen/arch/arm/gic-v2.c       |  6 ++--
>  xen/arch/arm/mm.c           |  2 +-
>  3 files changed, 44 insertions(+), 28 deletions(-)
> 
> diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
> index c2b97fa21e..a798e0b256 100644
> --- a/xen/arch/arm/domain_build.c
> +++ b/xen/arch/arm/domain_build.c
> @@ -1288,6 +1288,39 @@ static int __init fdt_property_interrupts(const struct 
> kernel_info *kinfo,
>      return res;
>  }
>  
> +/*
> + * Wrapper to convert physical address from paddr_t to uint64_t and
> + * invoke fdt_begin_node(). This is required as the physical address
> + * provided as part of node name should not contain any leading
> + * zeroes. Thus, one should use PRIx64 (instead of PRIpaddr) to append
> + * unit (which contains the physical address) with name to generate a
> + * node name.
> + */
> +static int __init domain_fdt_begin_node(void *fdt, const char *name,
> +                                        uint64_t unit)
> +{
> +    /*
> +     * The size of the buffer to hold the longest possible string (i.e.
> +     * interrupt-controller@ + a 64-bit number + \0).
> +     */
> +    char buf[38];
> +    int ret;
> +
> +    /* ePAPR 3.4 */
> +    ret = snprintf(buf, sizeof(buf), "%s@%"PRIx64, name, unit);
> +
> +    if ( ret >= sizeof(buf) )
> +    {
> +        printk(XENLOG_ERR
> +               "Insufficient buffer. Minimum size required is %d\n",
> +               (ret + 1));
> +
> +        return -FDT_ERR_TRUNCATED;
> +    }
> +
> +    return fdt_begin_node(fdt, buf);
> +}
> +
>  static int __init make_memory_node(const struct domain *d,
>                                     void *fdt,
>                                     int addrcells, int sizecells,
> @@ -1296,8 +1329,6 @@ static int __init make_memory_node(const struct domain 
> *d,
>      unsigned int i;
>      int res, reg_size = addrcells + sizecells;
>      int nr_cells = 0;
> -    /* Placeholder for memory@ + a 64-bit number + \0 */
> -    char buf[24];
>      __be32 reg[NR_MEM_BANKS * 4 /* Worst case addrcells + sizecells */];
>      __be32 *cells;
>  
> @@ -1314,9 +1345,7 @@ static int __init make_memory_node(const struct domain 
> *d,
>  
>      dt_dprintk("Create memory node\n");
>  
> -    /* ePAPR 3.4 */
> -    snprintf(buf, sizeof(buf), "memory@%"PRIx64, mem->bank[i].start);
> -    res = fdt_begin_node(fdt, buf);
> +    res = domain_fdt_begin_node(fdt, "memory", mem->bank[i].start);
>      if ( res )
>          return res;
>  
> @@ -1375,16 +1404,13 @@ static int __init make_shm_memory_node(const struct 
> domain *d,
>      {
>          uint64_t start = mem->bank[i].start;
>          uint64_t size = mem->bank[i].size;
> -        /* Placeholder for xen-shmem@ + a 64-bit number + \0 */
> -        char buf[27];
>          const char compat[] = "xen,shared-memory-v1";
>          /* Worst case addrcells + sizecells */
>          __be32 reg[GUEST_ROOT_ADDRESS_CELLS + GUEST_ROOT_SIZE_CELLS];
>          __be32 *cells;
>          unsigned int len = (addrcells + sizecells) * sizeof(__be32);
>  
> -        snprintf(buf, sizeof(buf), "xen-shmem@%"PRIx64, mem->bank[i].start);
> -        res = fdt_begin_node(fdt, buf);
> +        res = domain_fdt_begin_node(fdt, "xen-shmem", mem->bank[i].start);
>          if ( res )
>              return res;
>  
> @@ -2716,12 +2742,9 @@ static int __init make_gicv2_domU_node(struct 
> kernel_info *kinfo)
>      __be32 reg[(GUEST_ROOT_ADDRESS_CELLS + GUEST_ROOT_SIZE_CELLS) * 2];
>      __be32 *cells;
>      const struct domain *d = kinfo->d;
> -    /* Placeholder for interrupt-controller@ + a 64-bit number + \0 */
> -    char buf[38];
>  
> -    snprintf(buf, sizeof(buf), "interrupt-controller@%"PRIx64,
> -             vgic_dist_base(&d->arch.vgic));
> -    res = fdt_begin_node(fdt, buf);
> +    res = domain_fdt_begin_node(fdt, "interrupt-controller",
> +                                vgic_dist_base(&d->arch.vgic));
>      if ( res )
>          return res;
>  
> @@ -2771,14 +2794,10 @@ static int __init make_gicv3_domU_node(struct 
> kernel_info *kinfo)
>      int res = 0;
>      __be32 *reg, *cells;
>      const struct domain *d = kinfo->d;
> -    /* Placeholder for interrupt-controller@ + a 64-bit number + \0 */
> -    char buf[38];
>      unsigned int i, len = 0;
>  
> -    snprintf(buf, sizeof(buf), "interrupt-controller@%"PRIx64,
> -             vgic_dist_base(&d->arch.vgic));
> -
> -    res = fdt_begin_node(fdt, buf);
> +    res = domain_fdt_begin_node(fdt, "interrupt-controller",
> +                                vgic_dist_base(&d->arch.vgic));
>      if ( res )
>          return res;
>  
> @@ -2858,11 +2877,8 @@ static int __init make_vpl011_uart_node(struct 
> kernel_info *kinfo)
>      __be32 reg[GUEST_ROOT_ADDRESS_CELLS + GUEST_ROOT_SIZE_CELLS];
>      __be32 *cells;
>      struct domain *d = kinfo->d;
> -    /* Placeholder for sbsa-uart@ + a 64-bit number + \0 */
> -    char buf[27];
>  
> -    snprintf(buf, sizeof(buf), "sbsa-uart@%"PRIx64, 
> d->arch.vpl011.base_addr);
> -    res = fdt_begin_node(fdt, buf);
> +    res = domain_fdt_begin_node(fdt, "sbsa-uart", d->arch.vpl011.base_addr);
>      if ( res )
>          return res;
>  
> diff --git a/xen/arch/arm/gic-v2.c b/xen/arch/arm/gic-v2.c
> index 61802839cb..5d4d298b86 100644
> --- a/xen/arch/arm/gic-v2.c
> +++ b/xen/arch/arm/gic-v2.c
> @@ -1049,7 +1049,7 @@ static void __init gicv2_dt_init(void)
>      if ( csize < SZ_8K )
>      {
>          printk(XENLOG_WARNING "GICv2: WARNING: "
> -               "The GICC size is too small: %#"PRIx64" expected %#x\n",
> +               "The GICC size is too small: %#"PRIpaddr" expected %#x\n",
>                 csize, SZ_8K);
>          if ( platform_has_quirk(PLATFORM_QUIRK_GIC_64K_STRIDE) )
>          {
> @@ -1280,11 +1280,11 @@ static int __init gicv2_init(void)
>          gicv2.map_cbase += aliased_offset;
>  
>          printk(XENLOG_WARNING
> -               "GICv2: Adjusting CPU interface base to %#"PRIx64"\n",
> +               "GICv2: Adjusting CPU interface base to %#"PRIpaddr"\n",
>                 cbase + aliased_offset);
>      } else if ( csize == SZ_128K )
>          printk(XENLOG_WARNING
> -               "GICv2: GICC size=%#"PRIx64" but not aliased\n",
> +               "GICv2: GICC size=%#"PRIpaddr" but not aliased\n",
>                 csize);
>  
>      gicv2.map_hbase = ioremap_nocache(hbase, PAGE_SIZE);
> diff --git a/xen/arch/arm/mm.c b/xen/arch/arm/mm.c
> index f758cad545..b99806af99 100644
> --- a/xen/arch/arm/mm.c
> +++ b/xen/arch/arm/mm.c
> @@ -263,7 +263,7 @@ void dump_pt_walk(paddr_t ttbr, paddr_t addr,
>  
>          pte = mapping[offsets[level]];
>  
> -        printk("%s[0x%03x] = 0x%"PRIpaddr"\n",
> +        printk("%s[0x%03x] = 0x%"PRIx64"\n",
>                 level_strs[level], offsets[level], pte.bits);
>  
>          if ( level == 3 || !pte.walk.valid || !pte.walk.table )
> -- 
> 2.17.1
>