p71924506
/
linux_old1
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

arm64: hibernate: add trans_pgd public functions 

trans_pgd_create_copy() and trans_pgd_map_page() are going to be
the basis for new shared code that handles page tables for cases
which are between kernels: kexec, and hibernate.

Note: Eventually, get_safe_page() will be moved into a function pointer
passed via argument, but for now keep it as is.

Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com>
Reviewed-by: James Morse <james.morse@arm.com>
[will: Keep these functions static until kexec needs them]
Signed-off-by: Will Deacon <will@kernel.org>
This commit is contained in:
Pavel Tatashin 2019-12-04 10:59:23 -05:00 committed by Will Deacon
parent 7ea4088938
commit a2c2e67923
1 changed files with 60 additions and 33 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

93
arch/arm64/kernel/hibernate.c
View File

@ -182,39 +182,15 @@ int arch_hibernation_header_restore(void *addr)
}
EXPORT_SYMBOL(arch_hibernation_header_restore);
/*
* Copies length bytes, starting at src_start into an new page,
* perform cache maintentance, then maps it at the specified address low
* address as executable.
*
* This is used by hibernate to copy the code it needs to execute when
* overwriting the kernel text. This function generates a new set of page
* tables, which it loads into ttbr0.
*
* Length is provided as we probably only want 4K of data, even on a 64K
* page system.
*/
static int create_safe_exec_page(void *src_start, size_t length,
unsigned long dst_addr,
phys_addr_t *phys_dst_addr)
static int trans_pgd_map_page(pgd_t *trans_pgd, void *page,
unsigned long dst_addr,
pgprot_t pgprot)
{
void *page = (void *)get_safe_page(GFP_ATOMIC);
pgd_t *trans_pgd;
pgd_t *pgdp;
pud_t *pudp;
pmd_t *pmdp;
pte_t *ptep;
if (!page)
return -ENOMEM;
memcpy(page, src_start, length);
__flush_icache_range((unsigned long)page, (unsigned long)page + length);
trans_pgd = (void *)get_safe_page(GFP_ATOMIC);
if (!trans_pgd)
return -ENOMEM;
pgdp = pgd_offset_raw(trans_pgd, dst_addr);
if (pgd_none(READ_ONCE(*pgdp))) {
pudp = (void *)get_safe_page(GFP_ATOMIC);
@ -242,6 +218,44 @@ static int create_safe_exec_page(void *src_start, size_t length,
ptep = pte_offset_kernel(pmdp, dst_addr);
set_pte(ptep, pfn_pte(virt_to_pfn(page), PAGE_KERNEL_EXEC));
return 0;
}
/*
* Copies length bytes, starting at src_start into an new page,
* perform cache maintenance, then maps it at the specified address low
* address as executable.
*
* This is used by hibernate to copy the code it needs to execute when
* overwriting the kernel text. This function generates a new set of page
* tables, which it loads into ttbr0.
*
* Length is provided as we probably only want 4K of data, even on a 64K
* page system.
*/
static int create_safe_exec_page(void *src_start, size_t length,
unsigned long dst_addr,
phys_addr_t *phys_dst_addr)
{
void *page = (void *)get_safe_page(GFP_ATOMIC);
pgd_t *trans_pgd;
int rc;
if (!page)
return -ENOMEM;
memcpy(page, src_start, length);
__flush_icache_range((unsigned long)page, (unsigned long)page + length);
trans_pgd = (void *)get_safe_page(GFP_ATOMIC);
if (!trans_pgd)
return -ENOMEM;
rc = trans_pgd_map_page(trans_pgd, page, dst_addr,
PAGE_KERNEL_EXEC);
if (rc)
return rc;
/*
* Load our new page tables. A strict BBM approach requires that we
* ensure that TLBs are free of any entries that may overlap with the
@ -462,6 +476,24 @@ static int copy_page_tables(pgd_t *dst_pgdp, unsigned long start,
return 0;
}
static int trans_pgd_create_copy(pgd_t **dst_pgdp, unsigned long start,
unsigned long end)
{
int rc;
pgd_t *trans_pgd = (pgd_t *)get_safe_page(GFP_ATOMIC);
if (!trans_pgd) {
pr_err("Failed to allocate memory for temporary page tables.\n");
return -ENOMEM;
}
rc = copy_page_tables(trans_pgd, start, end);
if (!rc)
*dst_pgdp = trans_pgd;
return rc;
}
/*
* Setup then Resume from the hibernate image using swsusp_arch_suspend_exit().
*
@ -483,12 +515,7 @@ int swsusp_arch_resume(void)
* Create a second copy of just the linear map, and use this when
* restoring.
*/
tmp_pg_dir = (pgd_t *)get_safe_page(GFP_ATOMIC);
if (!tmp_pg_dir) {
pr_err("Failed to allocate memory for temporary page tables.\n");
return -ENOMEM;
}
rc = copy_page_tables(tmp_pg_dir, PAGE_OFFSET, PAGE_END);
rc = trans_pgd_create_copy(&tmp_pg_dir, PAGE_OFFSET, PAGE_END);
if (rc)
return rc;