On Fri, Jul 03, 2020 at 01:51:09PM +0200, Claudio Imbrenda wrote:
> Allow allocating aligned virtual memory with alignment larger than only
> one page.
>
> Add a check that the backing pages were actually allocated.
>
> Export the alloc_vpages_aligned function to allow users to allocate
> non-backed aligned virtual addresses.
>
> Signed-off-by: Claudio Imbrenda <imbrenda@xxxxxxxxxxxxx>
> ---
> lib/vmalloc.h | 3 +++
> lib/vmalloc.c | 40 ++++++++++++++++++++++++++++++++--------
> 2 files changed, 35 insertions(+), 8 deletions(-)
>
> diff --git a/lib/vmalloc.h b/lib/vmalloc.h
> index 2b563f4..fa3fa22 100644
> --- a/lib/vmalloc.h
> +++ b/lib/vmalloc.h
> @@ -5,6 +5,9 @@
>
> /* Allocate consecutive virtual pages (without backing) */
> extern void *alloc_vpages(ulong nr);
> +/* Allocate consecutive and aligned virtual pages (without backing) */
> +extern void *alloc_vpages_aligned(ulong nr, unsigned int alignment_pages);
> +
> /* Allocate one virtual page (without backing) */
> extern void *alloc_vpage(void);
> /* Set the top of the virtual address space */
> diff --git a/lib/vmalloc.c b/lib/vmalloc.c
> index 9237a0f..2c482aa 100644
> --- a/lib/vmalloc.c
> +++ b/lib/vmalloc.c
> @@ -12,19 +12,28 @@
> #include "alloc.h"
> #include "alloc_phys.h"
> #include "alloc_page.h"
> +#include <bitops.h>
> #include "vmalloc.h"
>
> static struct spinlock lock;
> static void *vfree_top = 0;
> static void *page_root;
>
> -void *alloc_vpages(ulong nr)
> +/*
> + * Allocate a certain number of pages from the virtual address space (without
> + * physical backing).
> + *
> + * nr is the number of pages to allocate
> + * alignment_pages is the alignment of the allocation *in pages*
> + */
> +static void *alloc_vpages_intern(ulong nr, unsigned int alignment_pages)
This helper function isn't necessary. Just introduce
alloc_vpages_aligned() and then call alloc_vpages_aligned(nr, 1) from
alloc_vpages().
> {
> uintptr_t ptr;
>
> spin_lock(&lock);
> ptr = (uintptr_t)vfree_top;
> ptr -= PAGE_SIZE * nr;
> + ptr &= GENMASK_ULL(63, PAGE_SHIFT + get_order(alignment_pages));
> vfree_top = (void *)ptr;
> spin_unlock(&lock);
>
> @@ -32,6 +41,16 @@ void *alloc_vpages(ulong nr)
> return (void *)ptr;
> }
>
> +void *alloc_vpages(ulong nr)
> +{
> + return alloc_vpages_intern(nr, 1);
> +}
> +
> +void *alloc_vpages_aligned(ulong nr, unsigned int alignment_pages)
> +{
> + return alloc_vpages_intern(nr, alignment_pages);
> +}
> +
> void *alloc_vpage(void)
> {
> return alloc_vpages(1);
> @@ -55,17 +74,22 @@ void *vmap(phys_addr_t phys, size_t size)
> return mem;
> }
>
> +/*
> + * Allocate virtual memory, with the specified minimum alignment.
> + */
> static void *vm_memalign(size_t alignment, size_t size)
> {
> + phys_addr_t pa;
> void *mem, *p;
> - size_t pages;
>
> - assert(alignment <= PAGE_SIZE);
> - size = PAGE_ALIGN(size);
> - pages = size / PAGE_SIZE;
> - mem = p = alloc_vpages(pages);
> - while (pages--) {
> - phys_addr_t pa = virt_to_phys(alloc_page());
> + assert(is_power_of_2(alignment));
> +
> + size = PAGE_ALIGN(size) / PAGE_SIZE;
> + alignment = PAGE_ALIGN(alignment) / PAGE_SIZE;
> + mem = p = alloc_vpages_intern(size, alignment);
> + while (size--) {
> + pa = virt_to_phys(alloc_page());
> + assert(pa);
> install_page(page_root, pa, p);
> p += PAGE_SIZE;
> }
> --
> 2.26.2
>
Otherwise
Reviewed-by: Andrew Jones <drjones@xxxxxxxxxx>
Thanks,
drew
