kexec is going to use a different allocator, so make
trans_pgd_map_page to accept allocator as an argument, and also
kexec is going to use a different map protection, so also pass
it via argument.
Signed-off-by: Pavel Tatashin <[email protected]>
Reviewed-by: Matthias Brugger <[email protected]>
---
arch/arm64/include/asm/trans_pgd.h | 18 ++++++++++++++++--
arch/arm64/kernel/hibernate.c | 12 +++++++++++-
arch/arm64/mm/trans_pgd.c | 27 +++++++++++++++++++++------
3 files changed, 48 insertions(+), 9 deletions(-)
diff --git a/arch/arm64/include/asm/trans_pgd.h b/arch/arm64/include/asm/trans_pgd.h
index 23153c13d1ce..ad5194ad178d 100644
--- a/arch/arm64/include/asm/trans_pgd.h
+++ b/arch/arm64/include/asm/trans_pgd.h
@@ -12,10 +12,24 @@
#include <linux/types.h>
#include <asm/pgtable-types.h>
+/*
+ * trans_alloc_page
+ * - Allocator that should return exactly one zeroed page, if this
+ * allocator fails, trans_pgd returns -ENOMEM error.
+ *
+ * trans_alloc_arg
+ * - Passed to trans_alloc_page as an argument
+ */
+
+struct trans_pgd_info {
+ void * (*trans_alloc_page)(void *arg);
+ void *trans_alloc_arg;
+};
+
int trans_pgd_create_copy(pgd_t **dst_pgdp, unsigned long start,
unsigned long end);
-int trans_pgd_map_page(pgd_t *trans_pgd, void *page, unsigned long dst_addr,
- pgprot_t pgprot);
+int trans_pgd_map_page(struct trans_pgd_info *info, pgd_t *trans_pgd,
+ void *page, unsigned long dst_addr, pgprot_t pgprot);
#endif /* _ASM_TRANS_TABLE_H */
diff --git a/arch/arm64/kernel/hibernate.c b/arch/arm64/kernel/hibernate.c
index 3d6f0fd73591..607bb1fbc349 100644
--- a/arch/arm64/kernel/hibernate.c
+++ b/arch/arm64/kernel/hibernate.c
@@ -179,6 +179,11 @@ int arch_hibernation_header_restore(void *addr)
}
EXPORT_SYMBOL(arch_hibernation_header_restore);
+static void *hibernate_page_alloc(void *arg)
+{
+ return (void *)get_safe_page((gfp_t)(unsigned long)arg);
+}
+
/*
* Copies length bytes, starting at src_start into an new page,
* perform cache maintenance, then maps it at the specified address low
@@ -195,6 +200,11 @@ static int create_safe_exec_page(void *src_start, size_t length,
unsigned long dst_addr,
phys_addr_t *phys_dst_addr)
{
+ struct trans_pgd_info trans_info = {
+ .trans_alloc_page = hibernate_page_alloc,
+ .trans_alloc_arg = (void *)GFP_ATOMIC,
+ };
+
void *page = (void *)get_safe_page(GFP_ATOMIC);
pgd_t *trans_pgd;
int rc;
@@ -209,7 +219,7 @@ static int create_safe_exec_page(void *src_start, size_t length,
if (!trans_pgd)
return -ENOMEM;
- rc = trans_pgd_map_page(trans_pgd, page, dst_addr,
+ rc = trans_pgd_map_page(&trans_info, trans_pgd, page, dst_addr,
PAGE_KERNEL_EXEC);
if (rc)
return rc;
diff --git a/arch/arm64/mm/trans_pgd.c b/arch/arm64/mm/trans_pgd.c
index d20e48520cef..275a79935d7e 100644
--- a/arch/arm64/mm/trans_pgd.c
+++ b/arch/arm64/mm/trans_pgd.c
@@ -25,6 +25,11 @@
#include <linux/mm.h>
#include <linux/mmzone.h>
+static void *trans_alloc(struct trans_pgd_info *info)
+{
+ return info->trans_alloc_page(info->trans_alloc_arg);
+}
+
static void _copy_pte(pte_t *dst_ptep, pte_t *src_ptep, unsigned long addr)
{
pte_t pte = READ_ONCE(*src_ptep);
@@ -180,8 +185,18 @@ int trans_pgd_create_copy(pgd_t **dst_pgdp, unsigned long start,
return rc;
}
-int trans_pgd_map_page(pgd_t *trans_pgd, void *page, unsigned long dst_addr,
- pgprot_t pgprot)
+/*
+ * Add map entry to trans_pgd for a base-size page at PTE level.
+ * info: contains allocator and its argument
+ * trans_pgd: page table in which new map is added.
+ * page: page to be mapped.
+ * dst_addr: new VA address for the pages
+ * pgprot: protection for the page.
+ *
+ * Returns 0 on success, and -ENOMEM on failure.
+ */
+int trans_pgd_map_page(struct trans_pgd_info *info, pgd_t *trans_pgd,
+ void *page, unsigned long dst_addr, pgprot_t pgprot)
{
pgd_t *pgdp;
pud_t *pudp;
@@ -190,7 +205,7 @@ int trans_pgd_map_page(pgd_t *trans_pgd, void *page, unsigned long dst_addr,
pgdp = pgd_offset_raw(trans_pgd, dst_addr);
if (pgd_none(READ_ONCE(*pgdp))) {
- pudp = (void *)get_safe_page(GFP_ATOMIC);
+ pudp = trans_alloc(info);
if (!pudp)
return -ENOMEM;
pgd_populate(&init_mm, pgdp, pudp);
@@ -198,7 +213,7 @@ int trans_pgd_map_page(pgd_t *trans_pgd, void *page, unsigned long dst_addr,
pudp = pud_offset(pgdp, dst_addr);
if (pud_none(READ_ONCE(*pudp))) {
- pmdp = (void *)get_safe_page(GFP_ATOMIC);
+ pmdp = trans_alloc(info);
if (!pmdp)
return -ENOMEM;
pud_populate(&init_mm, pudp, pmdp);
@@ -206,14 +221,14 @@ int trans_pgd_map_page(pgd_t *trans_pgd, void *page, unsigned long dst_addr,
pmdp = pmd_offset(pudp, dst_addr);
if (pmd_none(READ_ONCE(*pmdp))) {
- ptep = (void *)get_safe_page(GFP_ATOMIC);
+ ptep = trans_alloc(info);
if (!ptep)
return -ENOMEM;
pmd_populate_kernel(&init_mm, pmdp, ptep);
}
ptep = pte_offset_kernel(pmdp, dst_addr);
- set_pte(ptep, pfn_pte(virt_to_pfn(page), PAGE_KERNEL_EXEC));
+ set_pte(ptep, pfn_pte(virt_to_pfn(page), pgprot));
return 0;
}
--
2.17.1
Hi Pavel,
On 26/03/2020 03:24, Pavel Tatashin wrote:
> kexec is going to use a different allocator, so make
> trans_pgd_map_page to accept allocator as an argument, and also
> kexec is going to use a different map protection, so also pass
> it via argument.
This trans_pgd_map_page() used to be create_single_mapping() It creates page tables that
map one page: the relocation code.
Why do you need a different pgprot? Surely PAGE_KERNEL_EXEC is exactly what you want.
> diff --git a/arch/arm64/include/asm/trans_pgd.h b/arch/arm64/include/asm/trans_pgd.h
> index 23153c13d1ce..ad5194ad178d 100644
> --- a/arch/arm64/include/asm/trans_pgd.h
> +++ b/arch/arm64/include/asm/trans_pgd.h
> @@ -12,10 +12,24 @@
> #include <linux/types.h>
> #include <asm/pgtable-types.h>
>
> +/*
> + * trans_alloc_page
> + * - Allocator that should return exactly one zeroed page, if this
> + * allocator fails, trans_pgd returns -ENOMEM error.
trans_pgd is what you pass in to trans_pgd_map_page() or trans_pgd_create_copy().
Do you mean what those functions return?
> + *
> + * trans_alloc_arg
> + * - Passed to trans_alloc_page as an argument
> + */
> diff --git a/arch/arm64/kernel/hibernate.c b/arch/arm64/kernel/hibernate.c
> index 3d6f0fd73591..607bb1fbc349 100644
> --- a/arch/arm64/kernel/hibernate.c
> +++ b/arch/arm64/kernel/hibernate.c
> @@ -195,6 +200,11 @@ static int create_safe_exec_page(void *src_start, size_t length,
> unsigned long dst_addr,
> phys_addr_t *phys_dst_addr)
> {
> + struct trans_pgd_info trans_info = {
> + .trans_alloc_page = hibernate_page_alloc,
> + .trans_alloc_arg = (void *)GFP_ATOMIC,
> + };
As you need another copy of this in the next patch, is it worth declaring this globally
and making it const?
> diff --git a/arch/arm64/mm/trans_pgd.c b/arch/arm64/mm/trans_pgd.c
> index d20e48520cef..275a79935d7e 100644
> --- a/arch/arm64/mm/trans_pgd.c
> +++ b/arch/arm64/mm/trans_pgd.c
> @@ -180,8 +185,18 @@ int trans_pgd_create_copy(pgd_t **dst_pgdp, unsigned long start,
> return rc;
> }
>
> -int trans_pgd_map_page(pgd_t *trans_pgd, void *page, unsigned long dst_addr,
> - pgprot_t pgprot)
> +/*
> + * Add map entry to trans_pgd for a base-size page at PTE level.
> + * info: contains allocator and its argument
> + * trans_pgd: page table in which new map is added.
> + * page: page to be mapped.
> + * dst_addr: new VA address for the pages
~s/pages/page/
This thing only maps one page.
> + * pgprot: protection for the page.
> + *
> + * Returns 0 on success, and -ENOMEM on failure.
> + */
> +int trans_pgd_map_page(struct trans_pgd_info *info, pgd_t *trans_pgd,
> + void *page, unsigned long dst_addr, pgprot_t pgprot)
> {
> pgd_t *pgdp;
> pud_t *pudp;
Thanks,
James
Hi James,
I am working on an updated version of this patch series. We had back
and forth discussion on the list and off the list about MMU-enabled
series. So, I decided to sync the last series I had with the current
mainline. Address your last comments (those that I can address), and
send it again, so we can take a fresh look. I will reply to some of
your comments, as I address them in the synced version of my series.
On Wed, Apr 29, 2020 at 1:01 PM James Morse <[email protected]> wrote:
>
> Hi Pavel,
>
> On 26/03/2020 03:24, Pavel Tatashin wrote:
> > kexec is going to use a different allocator, so make
>
> > trans_pgd_map_page to accept allocator as an argument, and also
> > kexec is going to use a different map protection, so also pass
> > it via argument.
>
> This trans_pgd_map_page() used to be create_single_mapping() It creates page tables that
> map one page: the relocation code.
>
> Why do you need a different pgprot? Surely PAGE_KERNEL_EXEC is exactly what you want.
For hibernate case yes, but for MMU enabled kexec case, PAGE_KERNEL is
used, because it is used to copy data segments.
> > diff --git a/arch/arm64/include/asm/trans_pgd.h b/arch/arm64/include/asm/trans_pgd.h
> > index 23153c13d1ce..ad5194ad178d 100644
> > --- a/arch/arm64/include/asm/trans_pgd.h
> > +++ b/arch/arm64/include/asm/trans_pgd.h
> > @@ -12,10 +12,24 @@
> > #include <linux/types.h>
> > #include <asm/pgtable-types.h>
> >
> > +/*
> > + * trans_alloc_page
> > + * - Allocator that should return exactly one zeroed page, if this
> > + * allocator fails, trans_pgd returns -ENOMEM error.
>
> trans_pgd is what you pass in to trans_pgd_map_page() or trans_pgd_create_copy().
> Do you mean what those functions return?
I meant to say trans_pgd_*, but I will change the comment to
explicitly say trans_pgd_map_page() and trans_pgd_create_copy() will
return -ENOMEM.
>
>
> > + *
> > + * trans_alloc_arg
> > + * - Passed to trans_alloc_page as an argument
> > + */
>
> > diff --git a/arch/arm64/kernel/hibernate.c b/arch/arm64/kernel/hibernate.c
> > index 3d6f0fd73591..607bb1fbc349 100644
> > --- a/arch/arm64/kernel/hibernate.c
> > +++ b/arch/arm64/kernel/hibernate.c
> > @@ -195,6 +200,11 @@ static int create_safe_exec_page(void *src_start, size_t length,
> > unsigned long dst_addr,
> > phys_addr_t *phys_dst_addr)
> > {
> > + struct trans_pgd_info trans_info = {
> > + .trans_alloc_page = hibernate_page_alloc,
> > + .trans_alloc_arg = (void *)GFP_ATOMIC,
> > + };
>
> As you need another copy of this in the next patch, is it worth declaring this globally
> and making it const?
I think it is alright to have it on the stack instead of permanently
using the data section for this. Plus, we will have a different one
for the kexec case, so having this globally available will make it
strange.
>
>
> > diff --git a/arch/arm64/mm/trans_pgd.c b/arch/arm64/mm/trans_pgd.c
> > index d20e48520cef..275a79935d7e 100644
> > --- a/arch/arm64/mm/trans_pgd.c
> > +++ b/arch/arm64/mm/trans_pgd.c
> > @@ -180,8 +185,18 @@ int trans_pgd_create_copy(pgd_t **dst_pgdp, unsigned long start,
> > return rc;
> > }
> >
> > -int trans_pgd_map_page(pgd_t *trans_pgd, void *page, unsigned long dst_addr,
> > - pgprot_t pgprot)
> > +/*
> > + * Add map entry to trans_pgd for a base-size page at PTE level.
> > + * info: contains allocator and its argument
> > + * trans_pgd: page table in which new map is added.
> > + * page: page to be mapped.
>
> > + * dst_addr: new VA address for the pages
>
> ~s/pages/page/
>
> This thing only maps one page.
Sure, I will change that.
Thank you,
Pasha