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Message-ID: <CAJZ5v0iOiLaox4CNnqRFXsY9N=+0oNfP0SD1kCNzhU1Xpxv1YA@mail.gmail.com>
Date: Wed, 3 Aug 2016 23:28:48 +0200
From: "Rafael J. Wysocki" <rafael@...nel.org>
To: Yinghai Lu <yinghai@...nel.org>
Cc: Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com>,
"H . Peter Anvin" <hpa@...or.com>, Kees Cook <keescook@...omium.org>,
"Rafael J . Wysocki" <rjw@...ysocki.net>, Pavel Machek <pavel@....cz>,
"the arch/x86 maintainers" <x86@...nel.org>, Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
Linux PM list <linux-pm@...r.kernel.org>, kernel-hardening@...ts.openwall.com,
Thomas Garnier <thgarnie@...gle.com>
Subject: Re: [PATCH v2] x86/power/64: Support unaligned addresses for
temporary mapping
On Wed, Aug 3, 2016 at 8:23 PM, Yinghai Lu <yinghai@...nel.org> wrote:
> From: Thomas Garnier <thgarnie@...gle.com>
>
> Correctly setup the temporary mapping for hibernation. Previous
> implementation assumed the offset between KVA and PA was aligned on the PGD level.
> With KASLR memory randomization enabled, the offset is randomized on the PUD
> level. This change supports unaligned up to PMD.
>
> Signed-off-by: Thomas Garnier <thgarnie@...gle.com>
> [yinghai: change loop to virtual address]
> Signed-off-by: Yinghai Lu <yinghai@...nel.org>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> ---
> arch/x86/mm/ident_map.c | 54 ++++++++++++++++++++++++++++--------------------
> 1 file changed, 32 insertions(+), 22 deletions(-)
>
> Index: linux-2.6/arch/x86/mm/ident_map.c
> ===================================================================
> --- linux-2.6.orig/arch/x86/mm/ident_map.c
> +++ linux-2.6/arch/x86/mm/ident_map.c
> @@ -3,40 +3,47 @@
> * included by both the compressed kernel and the regular kernel.
> */
>
> -static void ident_pmd_init(unsigned long pmd_flag, pmd_t *pmd_page,
> +static void ident_pmd_init(struct x86_mapping_info *info, pmd_t *pmd_page,
> unsigned long addr, unsigned long end)
> {
> - addr &= PMD_MASK;
> - for (; addr < end; addr += PMD_SIZE) {
> - pmd_t *pmd = pmd_page + pmd_index(addr);
> + unsigned long off = info->kernel_mapping ? __PAGE_OFFSET : 0;
> + unsigned long vaddr = addr + off;
> + unsigned long vend = end + off;
> +
> + vaddr &= PMD_MASK;
> + for (; vaddr < vend; vaddr += PMD_SIZE) {
> + pmd_t *pmd = pmd_page + pmd_index(vaddr);
>
> if (!pmd_present(*pmd))
> - set_pmd(pmd, __pmd(addr | pmd_flag));
> + set_pmd(pmd, __pmd((vaddr - off) | info->pmd_flag));
> }
> }
>
> static int ident_pud_init(struct x86_mapping_info *info, pud_t *pud_page,
> unsigned long addr, unsigned long end)
> {
> - unsigned long next;
> + unsigned long off = info->kernel_mapping ? __PAGE_OFFSET : 0;
> + unsigned long vaddr = addr + off;
> + unsigned long vend = end + off;
> + unsigned long vnext;
>
> - for (; addr < end; addr = next) {
> - pud_t *pud = pud_page + pud_index(addr);
> + for (; vaddr < vend; vaddr = vnext) {
> + pud_t *pud = pud_page + pud_index(vaddr);
> pmd_t *pmd;
>
> - next = (addr & PUD_MASK) + PUD_SIZE;
> - if (next > end)
> - next = end;
> + vnext = (vaddr & PUD_MASK) + PUD_SIZE;
> + if (vnext > vend)
> + vnext = vend;
>
> if (pud_present(*pud)) {
> pmd = pmd_offset(pud, 0);
> - ident_pmd_init(info->pmd_flag, pmd, addr, next);
> + ident_pmd_init(info, pmd, vaddr - off, vnext - off);
> continue;
> }
> pmd = (pmd_t *)info->alloc_pgt_page(info->context);
> if (!pmd)
> return -ENOMEM;
> - ident_pmd_init(info->pmd_flag, pmd, addr, next);
> + ident_pmd_init(info, pmd, vaddr - off, vnext - off);
> set_pud(pud, __pud(__pa(pmd) | _KERNPG_TABLE));
> }
>
> @@ -46,21 +53,24 @@ static int ident_pud_init(struct x86_map
> int kernel_ident_mapping_init(struct x86_mapping_info *info, pgd_t *pgd_page,
> unsigned long addr, unsigned long end)
> {
> - unsigned long next;
> int result;
> - int off = info->kernel_mapping ? pgd_index(__PAGE_OFFSET) : 0;
> + unsigned long off = info->kernel_mapping ? __PAGE_OFFSET : 0;
> + unsigned long vaddr = addr + off;
> + unsigned long vend = end + off;
> + unsigned long vnext;
>
> - for (; addr < end; addr = next) {
> - pgd_t *pgd = pgd_page + pgd_index(addr) + off;
> + for (; vaddr < vend; vaddr = vnext) {
> + pgd_t *pgd = pgd_page + pgd_index(vaddr);
> pud_t *pud;
>
> - next = (addr & PGDIR_MASK) + PGDIR_SIZE;
> - if (next > end)
> - next = end;
> + vnext = (vaddr & PGDIR_MASK) + PGDIR_SIZE;
> + if (vnext > vend)
> + vnext = vend;
>
> if (pgd_present(*pgd)) {
> pud = pud_offset(pgd, 0);
> - result = ident_pud_init(info, pud, addr, next);
> + result = ident_pud_init(info, pud, vaddr - off,
> + vnext - off);
> if (result)
> return result;
> continue;
> @@ -69,7 +79,7 @@ int kernel_ident_mapping_init(struct x86
> pud = (pud_t *)info->alloc_pgt_page(info->context);
> if (!pud)
> return -ENOMEM;
> - result = ident_pud_init(info, pud, addr, next);
> + result = ident_pud_init(info, pud, vaddr - off, vnext - off);
> if (result)
> return result;
> set_pgd(pgd, __pgd(__pa(pud) | _KERNPG_TABLE));
> --
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