Re: [PATCH 2/4] arm64: gicv3: its: Add range check for number of allocated pages

From: Marc Zyngier
Date: Wed May 20 2015 - 08:13:05 EST


On Sun, 3 May 2015 21:49:30 +0100
Robert Richter <rric@xxxxxxxxxx> wrote:

> From: Robert Richter <rrichter@xxxxxxxxxx>
>
> The number of pages for the its table may exceed the maximum of 256.
> Adding a range check and limitting the number to its maximum.
>
> Based on a patch from Tirumalesh Chalamarla <tchalamarla@xxxxxxxxxx>.
>
> Signed-off-by: Robert Richter <rrichter@xxxxxxxxxx>

Looks good to me.

Reviewed-by: Marc Zyngier <marc.zyngier@xxxxxxx>

M.

> ---
> drivers/irqchip/irq-gic-v3-its.c | 11 ++++++++++-
> include/linux/irqchip/arm-gic-v3.h | 1 +
> 2 files changed, 11 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
> index e30b4de04c6c..a2619a1d5bb3 100644
> --- a/drivers/irqchip/irq-gic-v3-its.c
> +++ b/drivers/irqchip/irq-gic-v3-its.c
> @@ -810,6 +810,7 @@ static int its_alloc_tables(struct its_node *its)
> u64 entry_size = GITS_BASER_ENTRY_SIZE(val);
> int order = get_order(psz);
> int alloc_size;
> + int alloc_pages;
> u64 tmp;
> void *base;
>
> @@ -837,6 +838,14 @@ static int its_alloc_tables(struct its_node *its)
> }
>
> alloc_size = (1 << order) * PAGE_SIZE;
> + alloc_pages = (alloc_size / psz);
> + if (alloc_pages > GITS_BASER_PAGES_MAX) {
> + alloc_pages = GITS_BASER_PAGES_MAX;
> + order = get_order(GITS_BASER_PAGES_MAX * psz);
> + pr_warn("%s: Device Table too large, reduce its page order to %u (%u pages)\n",
> + its->msi_chip.of_node->full_name, order, alloc_pages);
> + }
> +
> base = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
> if (!base) {
> err = -ENOMEM;
> @@ -865,7 +874,7 @@ static int its_alloc_tables(struct its_node *its)
> break;
> }
>
> - val |= (alloc_size / psz) - 1;
> + val |= alloc_pages - 1;
>
> writeq_relaxed(val, its->base + GITS_BASER + i * 8);
> tmp = readq_relaxed(its->base + GITS_BASER + i * 8);
> diff --git a/include/linux/irqchip/arm-gic-v3.h b/include/linux/irqchip/arm-gic-v3.h
> index ffbc034c8810..f28da189c4aa 100644
> --- a/include/linux/irqchip/arm-gic-v3.h
> +++ b/include/linux/irqchip/arm-gic-v3.h
> @@ -229,6 +229,7 @@
> #define GITS_BASER_PAGE_SIZE_16K (1UL << GITS_BASER_PAGE_SIZE_SHIFT)
> #define GITS_BASER_PAGE_SIZE_64K (2UL << GITS_BASER_PAGE_SIZE_SHIFT)
> #define GITS_BASER_PAGE_SIZE_MASK (3UL << GITS_BASER_PAGE_SIZE_SHIFT)
> +#define GITS_BASER_PAGES_MAX 256
>
> #define GITS_BASER_TYPE_NONE 0
> #define GITS_BASER_TYPE_DEVICE 1



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