lkml.org 
[lkml]   [2018]   [Feb]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[tip:x86/mm] x86/mm/encrypt: Simplify sme_pgtable_calc()
Commit-ID:  1070730c1ad2bd49b0d11112728f1f4390137728
Gitweb: https://git.kernel.org/tip/1070730c1ad2bd49b0d11112728f1f4390137728
Author: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
AuthorDate: Wed, 31 Jan 2018 16:54:04 +0300
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 13 Feb 2018 15:59:49 +0100

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>
---
arch/x86/mm/mem_encrypt_identity.c | 42 +++++++++++---------------------------
1 file changed, 12 insertions(+), 30 deletions(-)

diff --git a/arch/x86/mm/mem_encrypt_identity.c b/arch/x86/mm/mem_encrypt_identity.c
index 4b6a2e3..b4139c5 100644
--- a/arch/x86/mm/mem_encrypt_identity.c
+++ b/arch/x86/mm/mem_encrypt_identity.c
@@ -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)
\
 
 \ /
  Last update: 2018-02-13 16:44    [W:0.098 / U:3.268 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site