From: Mark Rutland <mark.rutland@arm.com> To: Jun Yao <yaojun8558363@gmail.com> Cc: linux-arm-kernel@lists.infradead.org, catalin.marinas@arm.com, will.deacon@arm.com, james.morse@arm.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH v5 5/6] arm64/mm: Populate the swapper_pg_dir by fixmap. Date: Mon, 24 Sep 2018 17:54:21 +0100 [thread overview] Message-ID: <20180924165421.77bjq5m32h5w7ffh@lakrids.cambridge.arm.com> (raw) In-Reply-To: <20180917044333.30051-6-yaojun8558363@gmail.com> On Mon, Sep 17, 2018 at 12:43:32PM +0800, Jun Yao wrote: > Since we will move the swapper_pg_dir to rodata section, we need a > way to update it. The fixmap can handle it. When the swapper_pg_dir > needs to be updated, we map it dynamically. The map will be > canceled after the update is complete. In this way, we can defend > against KSMA(Kernel Space Mirror Attack). > > Signed-off-by: Jun Yao <yaojun8558363@gmail.com> > --- > arch/arm64/include/asm/pgtable.h | 38 ++++++++++++++++++++++++++------ > arch/arm64/mm/mmu.c | 25 +++++++++++++++++++-- > 2 files changed, 54 insertions(+), 9 deletions(-) > > diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h > index b11d6fc62a62..9e643fc2453d 100644 > --- a/arch/arm64/include/asm/pgtable.h > +++ b/arch/arm64/include/asm/pgtable.h > @@ -429,8 +429,29 @@ extern pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn, > PUD_TYPE_TABLE) > #endif > > +extern pgd_t init_pg_dir[PTRS_PER_PGD]; > +extern pgd_t init_pg_end[]; > +extern pgd_t swapper_pg_dir[PTRS_PER_PGD]; > +extern pgd_t swapper_pg_end[]; > +extern pgd_t idmap_pg_dir[PTRS_PER_PGD]; > +extern pgd_t tramp_pg_dir[PTRS_PER_PGD]; > + > +extern void set_swapper_pgd(pgd_t *pgdp, pgd_t pgd); > + > +static inline bool in_swapper_pgdir(void *addr) > +{ > + return ((unsigned long)addr & PAGE_MASK) == > + ((unsigned long)swapper_pg_dir & PAGE_MASK); > +} > + > static inline void set_pmd(pmd_t *pmdp, pmd_t pmd) > { > +#ifdef __PAGETABLE_PMD_FOLDED > + if (in_swapper_pgdir(pmdp)) { > + set_swapper_pgd((pgd_t *)pmdp, __pgd(pmd_val(pmd))); > + return; > + } > +#endif So that we can get consistent build coverage, could we make this: if (__is_defined(__PAGETABLE_PMD_FOLDED) && in_swapper_pgdir(pmdp)) { set_swapper_pgd((pgd_t *)pmdp, __pgd(pmd_val(pmd))); return; } > WRITE_ONCE(*pmdp, pmd); > > if (pmd_valid(pmd)) > @@ -484,6 +505,12 @@ static inline phys_addr_t pmd_page_paddr(pmd_t pmd) > > static inline void set_pud(pud_t *pudp, pud_t pud) > { > +#ifdef __PAGETABLE_PUD_FOLDED > + if (in_swapper_pgdir(pudp)) { > + set_swapper_pgd((pgd_t *)pudp, __pgd(pud_val(pud))); > + return; > + } > +#endif ... and likewise: if (__is_enabled(__PAGETABLE_PUD_FOLDED) && in_swapper_pgdir(pudp)) { set_swapper_pgd((pgd_t *)pudp, __pgd(pud_val(pud))); return; } Thanks, Mark.
WARNING: multiple messages have this Message-ID (diff)
From: mark.rutland@arm.com (Mark Rutland) To: linux-arm-kernel@lists.infradead.org Subject: [PATCH v5 5/6] arm64/mm: Populate the swapper_pg_dir by fixmap. Date: Mon, 24 Sep 2018 17:54:21 +0100 [thread overview] Message-ID: <20180924165421.77bjq5m32h5w7ffh@lakrids.cambridge.arm.com> (raw) In-Reply-To: <20180917044333.30051-6-yaojun8558363@gmail.com> On Mon, Sep 17, 2018 at 12:43:32PM +0800, Jun Yao wrote: > Since we will move the swapper_pg_dir to rodata section, we need a > way to update it. The fixmap can handle it. When the swapper_pg_dir > needs to be updated, we map it dynamically. The map will be > canceled after the update is complete. In this way, we can defend > against KSMA(Kernel Space Mirror Attack). > > Signed-off-by: Jun Yao <yaojun8558363@gmail.com> > --- > arch/arm64/include/asm/pgtable.h | 38 ++++++++++++++++++++++++++------ > arch/arm64/mm/mmu.c | 25 +++++++++++++++++++-- > 2 files changed, 54 insertions(+), 9 deletions(-) > > diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h > index b11d6fc62a62..9e643fc2453d 100644 > --- a/arch/arm64/include/asm/pgtable.h > +++ b/arch/arm64/include/asm/pgtable.h > @@ -429,8 +429,29 @@ extern pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn, > PUD_TYPE_TABLE) > #endif > > +extern pgd_t init_pg_dir[PTRS_PER_PGD]; > +extern pgd_t init_pg_end[]; > +extern pgd_t swapper_pg_dir[PTRS_PER_PGD]; > +extern pgd_t swapper_pg_end[]; > +extern pgd_t idmap_pg_dir[PTRS_PER_PGD]; > +extern pgd_t tramp_pg_dir[PTRS_PER_PGD]; > + > +extern void set_swapper_pgd(pgd_t *pgdp, pgd_t pgd); > + > +static inline bool in_swapper_pgdir(void *addr) > +{ > + return ((unsigned long)addr & PAGE_MASK) == > + ((unsigned long)swapper_pg_dir & PAGE_MASK); > +} > + > static inline void set_pmd(pmd_t *pmdp, pmd_t pmd) > { > +#ifdef __PAGETABLE_PMD_FOLDED > + if (in_swapper_pgdir(pmdp)) { > + set_swapper_pgd((pgd_t *)pmdp, __pgd(pmd_val(pmd))); > + return; > + } > +#endif So that we can get consistent build coverage, could we make this: if (__is_defined(__PAGETABLE_PMD_FOLDED) && in_swapper_pgdir(pmdp)) { set_swapper_pgd((pgd_t *)pmdp, __pgd(pmd_val(pmd))); return; } > WRITE_ONCE(*pmdp, pmd); > > if (pmd_valid(pmd)) > @@ -484,6 +505,12 @@ static inline phys_addr_t pmd_page_paddr(pmd_t pmd) > > static inline void set_pud(pud_t *pudp, pud_t pud) > { > +#ifdef __PAGETABLE_PUD_FOLDED > + if (in_swapper_pgdir(pudp)) { > + set_swapper_pgd((pgd_t *)pudp, __pgd(pud_val(pud))); > + return; > + } > +#endif ... and likewise: if (__is_enabled(__PAGETABLE_PUD_FOLDED) && in_swapper_pgdir(pudp)) { set_swapper_pgd((pgd_t *)pudp, __pgd(pud_val(pud))); return; } Thanks, Mark.
next prev parent reply other threads:[~2018-09-24 16:54 UTC|newest] Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top 2018-09-17 4:43 [PATCH v5 0/6] Move swapper_pg_dir to rodata section Jun Yao 2018-09-17 4:43 ` Jun Yao 2018-09-17 4:43 ` [PATCH v5 1/6] arm64/mm: Introduce the init_pg_dir Jun Yao 2018-09-17 4:43 ` Jun Yao 2018-09-24 13:01 ` Mark Rutland 2018-09-24 13:01 ` Mark Rutland 2018-09-24 14:03 ` Mark Rutland 2018-09-24 14:03 ` Mark Rutland 2018-09-17 4:43 ` [PATCH v5 2/6] arm64/mm: Pass ttbr1 as a parameter to __enable_mmu() Jun Yao 2018-09-17 4:43 ` Jun Yao 2018-09-24 13:26 ` Mark Rutland 2018-09-24 13:26 ` Mark Rutland 2018-09-17 4:43 ` [PATCH v5 3/6] arm64/mm: Create the initial page table in the init_pg_dir Jun Yao 2018-09-17 4:43 ` Jun Yao 2018-09-24 13:34 ` Mark Rutland 2018-09-24 13:34 ` Mark Rutland 2018-10-01 13:49 ` James Morse 2018-10-01 13:49 ` James Morse 2018-09-17 4:43 ` [PATCH v5 4/6] arm64/mm: Create the final page table directly in swapper_pg_dir Jun Yao 2018-09-17 4:43 ` Jun Yao 2018-09-17 4:43 ` [PATCH v5 5/6] arm64/mm: Populate the swapper_pg_dir by fixmap Jun Yao 2018-09-17 4:43 ` Jun Yao 2018-09-24 16:36 ` Mark Rutland 2018-09-24 16:36 ` Mark Rutland 2018-10-01 10:41 ` James Morse 2018-10-01 10:41 ` James Morse 2018-10-01 13:49 ` James Morse 2018-10-01 13:49 ` James Morse 2018-09-24 16:54 ` Mark Rutland [this message] 2018-09-24 16:54 ` Mark Rutland 2018-09-17 4:43 ` [PATCH v5 6/6] arm64/mm: Move {idmap_pg_dir .. swapper_pg_dir} to rodata section Jun Yao 2018-09-17 4:43 ` Jun Yao 2018-09-21 22:26 ` [PATCH v5 0/6] Move swapper_pg_dir " James Morse 2018-09-21 22:26 ` James Morse 2018-09-25 8:56 ` Jun Yao 2018-09-25 8:56 ` Jun Yao 2018-09-24 17:19 ` Mark Rutland 2018-09-24 17:19 ` Mark Rutland 2018-09-25 9:53 ` Jun Yao 2018-09-25 9:53 ` Jun Yao 2018-09-25 14:06 ` Mark Rutland, catalin.marinas 2018-09-25 14:06 ` Mark Rutland 2018-09-25 14:38 ` Catalin Marinas 2018-09-25 14:38 ` Catalin Marinas 2018-10-03 13:33 ` James Morse 2018-10-03 13:33 ` James Morse
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