On 25/04/17 11:20, Kai-Heng Feng wrote:
> From: Yinghai Lu <yinghai at kernel.org>
>
> BugLink: https://bugs.launchpad.net/bugs/1686061
>
> In order to support on-demand page table creation when moving the
> kernel for KASLR, we need to use kernel_ident_mapping_init() in the
> decompression code.
>
> This splits it out into its own file for use outside of init_64.c.
> Additionally, checking for __pa/__va defines is added since they
> need to be overridden in the decompression code.
>
> [kees: rewrote changelog]
> Signed-off-by: Yinghai Lu <yinghai at kernel.org>
> Signed-off-by: Kees Cook <keescook at chromium.org>
> Cc: Andrew Morton <akpm at linux-foundation.org>
> Cc: Andy Lutomirski <luto at amacapital.net>
> Cc: Andy Lutomirski <luto at kernel.org>
> Cc: Baoquan He <bhe at redhat.com>
> Cc: Borislav Petkov <bp at alien8.de>
> Cc: Borislav Petkov <bp at suse.de>
> Cc: Brian Gerst <brgerst at gmail.com>
> Cc: Dave Young <dyoung at redhat.com>
> Cc: Denys Vlasenko <dvlasenk at redhat.com>
> Cc: H. Peter Anvin <hpa at zytor.com>
> Cc: Linus Torvalds <torvalds at linux-foundation.org>
> Cc: Peter Zijlstra <peterz at infradead.org>
> Cc: Thomas Gleixner <tglx at linutronix.de>
> Cc: Vivek Goyal <vgoyal at redhat.com>
> Cc: kernel-hardening at lists.openwall.com
> Cc: lasse.collin at tukaani.org
> Link: http://lkml.kernel.org/r/1462572095-11754-3-git-send-email-keescook@chromium.org
> Signed-off-by: Ingo Molnar <mingo at kernel.org>
> (cherry picked from commit cf4fb15b3110df070fe9829a1ef38fef8316fb90)
> Signed-off-by: Kai-Heng Feng <kai.heng.feng at canonical.com>
> ---
> arch/x86/include/asm/page.h | 5 +++
> arch/x86/mm/ident_map.c | 74 +++++++++++++++++++++++++++++++++++++++++++++
> arch/x86/mm/init_64.c | 74 +--------------------------------------------
> 3 files changed, 80 insertions(+), 73 deletions(-)
> create mode 100644 arch/x86/mm/ident_map.c
>
> diff --git a/arch/x86/include/asm/page.h b/arch/x86/include/asm/page.h
> index 802dde30c928..cf8f619b305f 100644
> --- a/arch/x86/include/asm/page.h
> +++ b/arch/x86/include/asm/page.h
> @@ -37,7 +37,10 @@ static inline void copy_user_page(void *to, void *from, unsigned long vaddr,
> alloc_page_vma(GFP_HIGHUSER | __GFP_ZERO | movableflags, vma, vaddr)
> #define __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE
>
> +#ifndef __pa
> #define __pa(x) __phys_addr((unsigned long)(x))
> +#endif
> +
> #define __pa_nodebug(x) __phys_addr_nodebug((unsigned long)(x))
> /* __pa_symbol should be used for C visible symbols.
> This seems to be the official gcc blessed way to do such arithmetic. */
> @@ -51,7 +54,9 @@ static inline void copy_user_page(void *to, void *from, unsigned long vaddr,
> #define __pa_symbol(x) \
> __phys_addr_symbol(__phys_reloc_hide((unsigned long)(x)))
>
> +#ifndef __va
> #define __va(x) ((void *)((unsigned long)(x)+PAGE_OFFSET))
> +#endif
>
> #define __boot_va(x) __va(x)
> #define __boot_pa(x) __pa(x)
> diff --git a/arch/x86/mm/ident_map.c b/arch/x86/mm/ident_map.c
> new file mode 100644
> index 000000000000..751ca920773a
> --- /dev/null
> +++ b/arch/x86/mm/ident_map.c
> @@ -0,0 +1,74 @@
> +
> +static void ident_pmd_init(unsigned long pmd_flag, 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);
> +
> + if (!pmd_present(*pmd))
> + set_pmd(pmd, __pmd(addr | 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;
> +
> + for (; addr < end; addr = next) {
> + pud_t *pud = pud_page + pud_index(addr);
> + pmd_t *pmd;
> +
> + next = (addr & PUD_MASK) + PUD_SIZE;
> + if (next > end)
> + next = end;
> +
> + if (pud_present(*pud)) {
> + pmd = pmd_offset(pud, 0);
> + ident_pmd_init(info->pmd_flag, pmd, addr, next);
> + continue;
> + }
> + pmd = (pmd_t *)info->alloc_pgt_page(info->context);
> + if (!pmd)
> + return -ENOMEM;
> + ident_pmd_init(info->pmd_flag, pmd, addr, next);
> + set_pud(pud, __pud(__pa(pmd) | _KERNPG_TABLE));
> + }
> +
> + return 0;
> +}
> +
> +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;
> +
> + for (; addr < end; addr = next) {
> + pgd_t *pgd = pgd_page + pgd_index(addr) + off;
> + pud_t *pud;
> +
> + next = (addr & PGDIR_MASK) + PGDIR_SIZE;
> + if (next > end)
> + next = end;
> +
> + if (pgd_present(*pgd)) {
> + pud = pud_offset(pgd, 0);
> + result = ident_pud_init(info, pud, addr, next);
> + if (result)
> + return result;
> + continue;
> + }
> +
> + pud = (pud_t *)info->alloc_pgt_page(info->context);
> + if (!pud)
> + return -ENOMEM;
> + result = ident_pud_init(info, pud, addr, next);
> + if (result)
> + return result;
> + set_pgd(pgd, __pgd(__pa(pud) | _KERNPG_TABLE));
> + }
> +
> + return 0;
> +}
> diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
> index ec081fe0ce2c..de271ab3864a 100644
> --- a/arch/x86/mm/init_64.c
> +++ b/arch/x86/mm/init_64.c
> @@ -56,79 +56,7 @@
>
> #include "mm_internal.h"
>
> -static void ident_pmd_init(unsigned long pmd_flag, 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);
> -
> - if (!pmd_present(*pmd))
> - set_pmd(pmd, __pmd(addr | 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;
> -
> - for (; addr < end; addr = next) {
> - pud_t *pud = pud_page + pud_index(addr);
> - pmd_t *pmd;
> -
> - next = (addr & PUD_MASK) + PUD_SIZE;
> - if (next > end)
> - next = end;
> -
> - if (pud_present(*pud)) {
> - pmd = pmd_offset(pud, 0);
> - ident_pmd_init(info->pmd_flag, pmd, addr, next);
> - continue;
> - }
> - pmd = (pmd_t *)info->alloc_pgt_page(info->context);
> - if (!pmd)
> - return -ENOMEM;
> - ident_pmd_init(info->pmd_flag, pmd, addr, next);
> - set_pud(pud, __pud(__pa(pmd) | _KERNPG_TABLE));
> - }
> -
> - return 0;
> -}
> -
> -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;
> -
> - for (; addr < end; addr = next) {
> - pgd_t *pgd = pgd_page + pgd_index(addr) + off;
> - pud_t *pud;
> -
> - next = (addr & PGDIR_MASK) + PGDIR_SIZE;
> - if (next > end)
> - next = end;
> -
> - if (pgd_present(*pgd)) {
> - pud = pud_offset(pgd, 0);
> - result = ident_pud_init(info, pud, addr, next);
> - if (result)
> - return result;
> - continue;
> - }
> -
> - pud = (pud_t *)info->alloc_pgt_page(info->context);
> - if (!pud)
> - return -ENOMEM;
> - result = ident_pud_init(info, pud, addr, next);
> - if (result)
> - return result;
> - set_pgd(pgd, __pgd(__pa(pud) | _KERNPG_TABLE));
> - }
> -
> - return 0;
> -}
> +#include "ident_map.c"
>
> /*
> * NOTE: pagetable_init alloc all the fixmap pagetables contiguous on the
>
As a prerequisite for the 3rd patch in the series, I'm OK with this
cherry pick to enable a clean cherry pick for the 3rd patch.
Acked-by: Colin Ian King <colin.king at canonical.com>