2019-11-14 01:12:11

by Max Filippov

Subject: [PATCH] xtensa: use MEMBLOCK_ALLOC_ANYWHERE for KASAN shadow map

KASAN shadow map doesn't need to be accessible through the linear kernel
mapping, allocate its pages with MEMBLOCK_ALLOC_ANYWHERE so that high
memory can be used. This frees up to ~100MB of low memory on xtensa
configurations with KASAN and high memory.

Cc: [email protected] # v5.1+
Fixes: f240ec09bb8a ("memblock: replace memblock_alloc_base(ANYWHERE)
with memblock_phys_alloc")
Signed-off-by: Max Filippov <[email protected]>
---
arch/xtensa/mm/kasan_init.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/xtensa/mm/kasan_init.c b/arch/xtensa/mm/kasan_init.c
index 9c957791bb33..e3baa21ff24c 100644
--- a/arch/xtensa/mm/kasan_init.c
+++ b/arch/xtensa/mm/kasan_init.c
@@ -60,7 +60,9 @@ static void __init populate(void *start, void *end)

for (k = 0; k < PTRS_PER_PTE; ++k, ++j) {
phys_addr_t phys =
- memblock_phys_alloc(PAGE_SIZE, PAGE_SIZE);
+ memblock_phys_alloc_range(PAGE_SIZE, PAGE_SIZE,
+ 0,
+ MEMBLOCK_ALLOC_ANYWHERE);

if (!phys)
panic("Failed to allocate page table page\n");
--
2.20.1

2019-11-14 08:15:01

by Mike Rapoport

Subject: Re: [PATCH] xtensa: use MEMBLOCK_ALLOC_ANYWHERE for KASAN shadow map

On Wed, Nov 13, 2019 at 05:08:24PM -0800, Max Filippov wrote:
> KASAN shadow map doesn't need to be accessible through the linear kernel
> mapping, allocate its pages with MEMBLOCK_ALLOC_ANYWHERE so that high
> memory can be used. This frees up to ~100MB of low memory on xtensa
> configurations with KASAN and high memory.
>
> Cc: [email protected] # v5.1+
> Fixes: f240ec09bb8a ("memblock: replace memblock_alloc_base(ANYWHERE)
> with memblock_phys_alloc")
> Signed-off-by: Max Filippov <[email protected]>

Reviewed-by: Mike Rapoport <[email protected]>

> ---
> arch/xtensa/mm/kasan_init.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/arch/xtensa/mm/kasan_init.c b/arch/xtensa/mm/kasan_init.c
> index 9c957791bb33..e3baa21ff24c 100644
> --- a/arch/xtensa/mm/kasan_init.c
> +++ b/arch/xtensa/mm/kasan_init.c
> @@ -60,7 +60,9 @@ static void __init populate(void *start, void *end)
>
> for (k = 0; k < PTRS_PER_PTE; ++k, ++j) {
> phys_addr_t phys =
> - memblock_phys_alloc(PAGE_SIZE, PAGE_SIZE);
> + memblock_phys_alloc_range(PAGE_SIZE, PAGE_SIZE,
> + 0,
> + MEMBLOCK_ALLOC_ANYWHERE);
>
> if (!phys)
> panic("Failed to allocate page table page\n");
> --
> 2.20.1
>

--
Sincerely yours,
Mike.