2020-03-26 03:25:16

by Pasha Tatashin

Subject: [PATCH v9 05/18] arm64: trans_pgd: pass NULL instead of init_mm to *_populate functions

trans_pgd_* should be independent from mm context because the tables that
are created by this code are used when there are no mm context around, as
it is between kernels. Simply replace mm_init's with NULL.

Signed-off-by: Pavel Tatashin <[email protected]>
---
arch/arm64/mm/trans_pgd.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/arch/arm64/mm/trans_pgd.c b/arch/arm64/mm/trans_pgd.c
index c16ae4e2b496..37d7d1c60f65 100644
--- a/arch/arm64/mm/trans_pgd.c
+++ b/arch/arm64/mm/trans_pgd.c
@@ -67,7 +67,7 @@ static int copy_pte(struct trans_pgd_info *info, pmd_t *dst_pmdp,
dst_ptep = trans_alloc(info);
if (!dst_ptep)
return -ENOMEM;
- pmd_populate_kernel(&init_mm, dst_pmdp, dst_ptep);
+ pmd_populate_kernel(NULL, dst_pmdp, dst_ptep);
dst_ptep = pte_offset_kernel(dst_pmdp, start);

src_ptep = pte_offset_kernel(src_pmdp, start);
@@ -90,7 +90,7 @@ static int copy_pmd(struct trans_pgd_info *info, pud_t *dst_pudp,
dst_pmdp = trans_alloc(info);
if (!dst_pmdp)
return -ENOMEM;
- pud_populate(&init_mm, dst_pudp, dst_pmdp);
+ pud_populate(NULL, dst_pudp, dst_pmdp);
}
dst_pmdp = pmd_offset(dst_pudp, start);

@@ -126,7 +126,7 @@ static int copy_pud(struct trans_pgd_info *info, pgd_t *dst_pgdp,
dst_pudp = trans_alloc(info);
if (!dst_pudp)
return -ENOMEM;
- pgd_populate(&init_mm, dst_pgdp, dst_pudp);
+ pgd_populate(NULL, dst_pgdp, dst_pudp);
}
dst_pudp = pud_offset(dst_pgdp, start);

@@ -218,7 +218,7 @@ int trans_pgd_map_page(struct trans_pgd_info *info, pgd_t *trans_pgd,
pudp = trans_alloc(info);
if (!pudp)
return -ENOMEM;
- pgd_populate(&init_mm, pgdp, pudp);
+ pgd_populate(NULL, pgdp, pudp);
}

pudp = pud_offset(pgdp, dst_addr);
@@ -226,7 +226,7 @@ int trans_pgd_map_page(struct trans_pgd_info *info, pgd_t *trans_pgd,
pmdp = trans_alloc(info);
if (!pmdp)
return -ENOMEM;
- pud_populate(&init_mm, pudp, pmdp);
+ pud_populate(NULL, pudp, pmdp);
}

pmdp = pmd_offset(pudp, dst_addr);
@@ -234,7 +234,7 @@ int trans_pgd_map_page(struct trans_pgd_info *info, pgd_t *trans_pgd,
ptep = trans_alloc(info);
if (!ptep)
return -ENOMEM;
- pmd_populate_kernel(&init_mm, pmdp, ptep);
+ pmd_populate_kernel(NULL, pmdp, ptep);
}

ptep = pte_offset_kernel(pmdp, dst_addr);
--
2.17.1

2020-04-29 17:04:06

by James Morse

Subject: Re: [PATCH v9 05/18] arm64: trans_pgd: pass NULL instead of init_mm to *_populate functions

Hi Pavel,

On 26/03/2020 03:24, Pavel Tatashin wrote:
> trans_pgd_* should be independent from mm context because the tables that
> are created by this code are used when there are no mm context around, as
> it is between kernels. Simply replace mm_init's with NULL.

arm64's p?d_populate() helpers don't use the mm parameter, so it doesn't make any
difference. This was originally done so that if we ever needed anything from the mm, we
didn't get a NULL dereference or EL0 behaviour due to a future '!= &init_mm'.

If you think it matters,
Acked-by: James Morse <[email protected]>


Thanks,

James

2021-01-23 00:25:31

by Pasha Tatashin

Subject: Re: [PATCH v9 05/18] arm64: trans_pgd: pass NULL instead of init_mm to *_populate functions

> Acked-by: James Morse <[email protected]>

Thank you for the review.
Pasha

>
>
> Thanks,
>
> James