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x86/mm/encrypt: Simplify sme_pgtable_calc() 

sme_pgtable_calc() is unnecessary complex. It can be re-written in a
more stream-lined way.

As a side effect, we would get the code ready to boot-time switching
between paging modes.

Tested-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20180131135404.40692-4-kirill.shutemov@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Kirill A. Shutemov 2018-01-31 16:54:04 +03:00 committed by Ingo Molnar
parent aad983913d
commit 1070730c1a
1 changed files with 12 additions and 30 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

42
arch/x86/mm/mem_encrypt_identity.c
View File

@ -231,8 +231,7 @@ static void __init sme_map_range_decrypted_wp(struct sme_populate_pgd_data *ppd)
static unsigned long __init sme_pgtable_calc(unsigned long len)
{
unsigned long p4d_size, pud_size, pmd_size, pte_size;
unsigned long total;
unsigned long entries = 0, tables = 0;
/*
* Perform a relatively simplistic calculation of the pagetable
@ -246,42 +245,25 @@ static unsigned long __init sme_pgtable_calc(unsigned long len)
* Incrementing the count for each covers the case where the addresses
* cross entries.
*/
if (IS_ENABLED(CONFIG_X86_5LEVEL)) {
p4d_size = (ALIGN(len, PGDIR_SIZE) / PGDIR_SIZE) + 1;
p4d_size *= sizeof(p4d_t) * PTRS_PER_P4D;
pud_size = (ALIGN(len, P4D_SIZE) / P4D_SIZE) + 1;
pud_size *= sizeof(pud_t) * PTRS_PER_PUD;
} else {
p4d_size = 0;
pud_size = (ALIGN(len, PGDIR_SIZE) / PGDIR_SIZE) + 1;
pud_size *= sizeof(pud_t) * PTRS_PER_PUD;
}
pmd_size = (ALIGN(len, PUD_SIZE) / PUD_SIZE) + 1;
pmd_size *= sizeof(pmd_t) * PTRS_PER_PMD;
pte_size = 2 * sizeof(pte_t) * PTRS_PER_PTE;
total = p4d_size + pud_size + pmd_size + pte_size;
/* PGDIR_SIZE is equal to P4D_SIZE on 4-level machine. */
if (PTRS_PER_P4D > 1)
entries += (DIV_ROUND_UP(len, PGDIR_SIZE) + 1) * sizeof(p4d_t) * PTRS_PER_P4D;
entries += (DIV_ROUND_UP(len, P4D_SIZE) + 1) * sizeof(pud_t) * PTRS_PER_PUD;
entries += (DIV_ROUND_UP(len, PUD_SIZE) + 1) * sizeof(pmd_t) * PTRS_PER_PMD;
entries += 2 * sizeof(pte_t) * PTRS_PER_PTE;
/*
* Now calculate the added pagetable structures needed to populate
* the new pagetables.
*/
if (IS_ENABLED(CONFIG_X86_5LEVEL)) {
p4d_size = ALIGN(total, PGDIR_SIZE) / PGDIR_SIZE;
p4d_size *= sizeof(p4d_t) * PTRS_PER_P4D;
pud_size = ALIGN(total, P4D_SIZE) / P4D_SIZE;
pud_size *= sizeof(pud_t) * PTRS_PER_PUD;
} else {
p4d_size = 0;
pud_size = ALIGN(total, PGDIR_SIZE) / PGDIR_SIZE;
pud_size *= sizeof(pud_t) * PTRS_PER_PUD;
}
pmd_size = ALIGN(total, PUD_SIZE) / PUD_SIZE;
pmd_size *= sizeof(pmd_t) * PTRS_PER_PMD;
total += p4d_size + pud_size + pmd_size;
if (PTRS_PER_P4D > 1)
tables += DIV_ROUND_UP(entries, PGDIR_SIZE) * sizeof(p4d_t) * PTRS_PER_P4D;
tables += DIV_ROUND_UP(entries, P4D_SIZE) * sizeof(pud_t) * PTRS_PER_PUD;
tables += DIV_ROUND_UP(entries, PUD_SIZE) * sizeof(pmd_t) * PTRS_PER_PMD;
return total;
return entries + tables;
}
void __init __nostackprotector sme_encrypt_kernel(struct boot_params *bp)