From: Russell Currey <ruscur@russell.cc> To: linuxppc-dev@lists.ozlabs.org Cc: ajd@linux.ibm.com, kernel-hardening@lists.openwall.com, npiggin@gmail.com, joel@jms.id.au, dja@axtens.net Subject: [PATCH v6 7/7] powerpc/32: use set_memory_attr() Date: Tue, 10 Mar 2020 12:03:38 +1100 [thread overview] Message-ID: <20200310010338.21205-8-ruscur@russell.cc> (raw) In-Reply-To: <20200310010338.21205-1-ruscur@russell.cc> From: Christophe Leroy <christophe.leroy@c-s.fr> Use set_memory_attr() instead of the PPC32 specific change_page_attr() change_page_attr() was checking that the address was not mapped by blocks and was handling highmem, but that's unneeded because the affected pages can't be in highmem and block mapping verification is already done by the callers. Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> --- arch/powerpc/mm/pgtable_32.c | 95 ++++-------------------------------- 1 file changed, 10 insertions(+), 85 deletions(-) diff --git a/arch/powerpc/mm/pgtable_32.c b/arch/powerpc/mm/pgtable_32.c index 5fb90edd865e..3d92eaf3ee2f 100644 --- a/arch/powerpc/mm/pgtable_32.c +++ b/arch/powerpc/mm/pgtable_32.c @@ -23,6 +23,7 @@ #include <linux/highmem.h> #include <linux/memblock.h> #include <linux/slab.h> +#include <linux/set_memory.h> #include <asm/pgtable.h> #include <asm/pgalloc.h> @@ -121,99 +122,20 @@ void __init mapin_ram(void) } } -/* Scan the real Linux page tables and return a PTE pointer for - * a virtual address in a context. - * Returns true (1) if PTE was found, zero otherwise. The pointer to - * the PTE pointer is unmodified if PTE is not found. - */ -static int -get_pteptr(struct mm_struct *mm, unsigned long addr, pte_t **ptep, pmd_t **pmdp) -{ - pgd_t *pgd; - pud_t *pud; - pmd_t *pmd; - pte_t *pte; - int retval = 0; - - pgd = pgd_offset(mm, addr & PAGE_MASK); - if (pgd) { - pud = pud_offset(pgd, addr & PAGE_MASK); - if (pud && pud_present(*pud)) { - pmd = pmd_offset(pud, addr & PAGE_MASK); - if (pmd_present(*pmd)) { - pte = pte_offset_map(pmd, addr & PAGE_MASK); - if (pte) { - retval = 1; - *ptep = pte; - if (pmdp) - *pmdp = pmd; - /* XXX caller needs to do pte_unmap, yuck */ - } - } - } - } - return(retval); -} - -static int __change_page_attr_noflush(struct page *page, pgprot_t prot) -{ - pte_t *kpte; - pmd_t *kpmd; - unsigned long address; - - BUG_ON(PageHighMem(page)); - address = (unsigned long)page_address(page); - - if (v_block_mapped(address)) - return 0; - if (!get_pteptr(&init_mm, address, &kpte, &kpmd)) - return -EINVAL; - __set_pte_at(&init_mm, address, kpte, mk_pte(page, prot), 0); - pte_unmap(kpte); - - return 0; -} - -/* - * Change the page attributes of an page in the linear mapping. - * - * THIS DOES NOTHING WITH BAT MAPPINGS, DEBUG USE ONLY - */ -static int change_page_attr(struct page *page, int numpages, pgprot_t prot) -{ - int i, err = 0; - unsigned long flags; - struct page *start = page; - - local_irq_save(flags); - for (i = 0; i < numpages; i++, page++) { - err = __change_page_attr_noflush(page, prot); - if (err) - break; - } - wmb(); - local_irq_restore(flags); - flush_tlb_kernel_range((unsigned long)page_address(start), - (unsigned long)page_address(page)); - return err; -} - void mark_initmem_nx(void) { - struct page *page = virt_to_page(_sinittext); unsigned long numpages = PFN_UP((unsigned long)_einittext) - PFN_DOWN((unsigned long)_sinittext); if (v_block_mapped((unsigned long)_stext + 1)) mmu_mark_initmem_nx(); else - change_page_attr(page, numpages, PAGE_KERNEL); + set_memory_attr((unsigned long)_sinittext, numpages, PAGE_KERNEL); } #ifdef CONFIG_STRICT_KERNEL_RWX void mark_rodata_ro(void) { - struct page *page; unsigned long numpages; if (v_block_mapped((unsigned long)_sinittext)) { @@ -222,20 +144,18 @@ void mark_rodata_ro(void) return; } - page = virt_to_page(_stext); numpages = PFN_UP((unsigned long)_etext) - PFN_DOWN((unsigned long)_stext); - change_page_attr(page, numpages, PAGE_KERNEL_ROX); + set_memory_attr((unsigned long)_stext, numpages, PAGE_KERNEL_ROX); /* * mark .rodata as read only. Use __init_begin rather than __end_rodata * to cover NOTES and EXCEPTION_TABLE. */ - page = virt_to_page(__start_rodata); numpages = PFN_UP((unsigned long)__init_begin) - PFN_DOWN((unsigned long)__start_rodata); - change_page_attr(page, numpages, PAGE_KERNEL_RO); + set_memory_attr((unsigned long)__start_rodata, numpages, PAGE_KERNEL_RO); // mark_initmem_nx() should have already run by now ptdump_check_wx(); @@ -245,9 +165,14 @@ void mark_rodata_ro(void) #ifdef CONFIG_DEBUG_PAGEALLOC void __kernel_map_pages(struct page *page, int numpages, int enable) { + unsigned long addr = (unsigned long)page_address(page); + if (PageHighMem(page)) return; - change_page_attr(page, numpages, enable ? PAGE_KERNEL : __pgprot(0)); + if (enable) + set_memory_attr(addr, numpages, PAGE_KERNEL); + else + set_memory_attr(addr, numpages, __pgprot(0)); } #endif /* CONFIG_DEBUG_PAGEALLOC */ -- 2.25.1
WARNING: multiple messages have this Message-ID (diff)
From: Russell Currey <ruscur@russell.cc> To: linuxppc-dev@lists.ozlabs.org Cc: Christophe Leroy <christophe.leroy@c-s.fr>, joel@jms.id.au, mpe@ellerman.id.au, ajd@linux.ibm.com, dja@axtens.net, npiggin@gmail.com, kernel-hardening@lists.openwall.com Subject: [PATCH v6 7/7] powerpc/32: use set_memory_attr() Date: Tue, 10 Mar 2020 12:03:38 +1100 [thread overview] Message-ID: <20200310010338.21205-8-ruscur@russell.cc> (raw) In-Reply-To: <20200310010338.21205-1-ruscur@russell.cc> From: Christophe Leroy <christophe.leroy@c-s.fr> Use set_memory_attr() instead of the PPC32 specific change_page_attr() change_page_attr() was checking that the address was not mapped by blocks and was handling highmem, but that's unneeded because the affected pages can't be in highmem and block mapping verification is already done by the callers. Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> --- arch/powerpc/mm/pgtable_32.c | 95 ++++-------------------------------- 1 file changed, 10 insertions(+), 85 deletions(-) diff --git a/arch/powerpc/mm/pgtable_32.c b/arch/powerpc/mm/pgtable_32.c index 5fb90edd865e..3d92eaf3ee2f 100644 --- a/arch/powerpc/mm/pgtable_32.c +++ b/arch/powerpc/mm/pgtable_32.c @@ -23,6 +23,7 @@ #include <linux/highmem.h> #include <linux/memblock.h> #include <linux/slab.h> +#include <linux/set_memory.h> #include <asm/pgtable.h> #include <asm/pgalloc.h> @@ -121,99 +122,20 @@ void __init mapin_ram(void) } } -/* Scan the real Linux page tables and return a PTE pointer for - * a virtual address in a context. - * Returns true (1) if PTE was found, zero otherwise. The pointer to - * the PTE pointer is unmodified if PTE is not found. - */ -static int -get_pteptr(struct mm_struct *mm, unsigned long addr, pte_t **ptep, pmd_t **pmdp) -{ - pgd_t *pgd; - pud_t *pud; - pmd_t *pmd; - pte_t *pte; - int retval = 0; - - pgd = pgd_offset(mm, addr & PAGE_MASK); - if (pgd) { - pud = pud_offset(pgd, addr & PAGE_MASK); - if (pud && pud_present(*pud)) { - pmd = pmd_offset(pud, addr & PAGE_MASK); - if (pmd_present(*pmd)) { - pte = pte_offset_map(pmd, addr & PAGE_MASK); - if (pte) { - retval = 1; - *ptep = pte; - if (pmdp) - *pmdp = pmd; - /* XXX caller needs to do pte_unmap, yuck */ - } - } - } - } - return(retval); -} - -static int __change_page_attr_noflush(struct page *page, pgprot_t prot) -{ - pte_t *kpte; - pmd_t *kpmd; - unsigned long address; - - BUG_ON(PageHighMem(page)); - address = (unsigned long)page_address(page); - - if (v_block_mapped(address)) - return 0; - if (!get_pteptr(&init_mm, address, &kpte, &kpmd)) - return -EINVAL; - __set_pte_at(&init_mm, address, kpte, mk_pte(page, prot), 0); - pte_unmap(kpte); - - return 0; -} - -/* - * Change the page attributes of an page in the linear mapping. - * - * THIS DOES NOTHING WITH BAT MAPPINGS, DEBUG USE ONLY - */ -static int change_page_attr(struct page *page, int numpages, pgprot_t prot) -{ - int i, err = 0; - unsigned long flags; - struct page *start = page; - - local_irq_save(flags); - for (i = 0; i < numpages; i++, page++) { - err = __change_page_attr_noflush(page, prot); - if (err) - break; - } - wmb(); - local_irq_restore(flags); - flush_tlb_kernel_range((unsigned long)page_address(start), - (unsigned long)page_address(page)); - return err; -} - void mark_initmem_nx(void) { - struct page *page = virt_to_page(_sinittext); unsigned long numpages = PFN_UP((unsigned long)_einittext) - PFN_DOWN((unsigned long)_sinittext); if (v_block_mapped((unsigned long)_stext + 1)) mmu_mark_initmem_nx(); else - change_page_attr(page, numpages, PAGE_KERNEL); + set_memory_attr((unsigned long)_sinittext, numpages, PAGE_KERNEL); } #ifdef CONFIG_STRICT_KERNEL_RWX void mark_rodata_ro(void) { - struct page *page; unsigned long numpages; if (v_block_mapped((unsigned long)_sinittext)) { @@ -222,20 +144,18 @@ void mark_rodata_ro(void) return; } - page = virt_to_page(_stext); numpages = PFN_UP((unsigned long)_etext) - PFN_DOWN((unsigned long)_stext); - change_page_attr(page, numpages, PAGE_KERNEL_ROX); + set_memory_attr((unsigned long)_stext, numpages, PAGE_KERNEL_ROX); /* * mark .rodata as read only. Use __init_begin rather than __end_rodata * to cover NOTES and EXCEPTION_TABLE. */ - page = virt_to_page(__start_rodata); numpages = PFN_UP((unsigned long)__init_begin) - PFN_DOWN((unsigned long)__start_rodata); - change_page_attr(page, numpages, PAGE_KERNEL_RO); + set_memory_attr((unsigned long)__start_rodata, numpages, PAGE_KERNEL_RO); // mark_initmem_nx() should have already run by now ptdump_check_wx(); @@ -245,9 +165,14 @@ void mark_rodata_ro(void) #ifdef CONFIG_DEBUG_PAGEALLOC void __kernel_map_pages(struct page *page, int numpages, int enable) { + unsigned long addr = (unsigned long)page_address(page); + if (PageHighMem(page)) return; - change_page_attr(page, numpages, enable ? PAGE_KERNEL : __pgprot(0)); + if (enable) + set_memory_attr(addr, numpages, PAGE_KERNEL); + else + set_memory_attr(addr, numpages, __pgprot(0)); } #endif /* CONFIG_DEBUG_PAGEALLOC */ -- 2.25.1
next prev parent reply other threads:[~2020-03-10 1:17 UTC|newest] Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-03-10 1:03 [PATCH v6 0/7] set_memory() routines and STRICT_MODULE_RWX Russell Currey 2020-03-10 1:03 ` Russell Currey 2020-03-10 1:03 ` [PATCH v6 1/7] powerpc/mm: Implement set_memory() routines Russell Currey 2020-03-10 1:03 ` Russell Currey 2020-03-11 6:03 ` Daniel Axtens 2020-03-11 6:03 ` Daniel Axtens 2020-03-31 1:49 ` Russell Currey 2020-03-31 1:49 ` Russell Currey 2020-03-10 1:03 ` [PATCH v6 2/7] powerpc/kprobes: Mark newly allocated probes as RO Russell Currey 2020-03-10 1:03 ` Russell Currey 2020-03-10 1:03 ` [PATCH v6 3/7] powerpc/mm/ptdump: debugfs handler for W+X checks at runtime Russell Currey 2020-03-10 1:03 ` Russell Currey 2020-03-10 1:03 ` [PATCH v6 4/7] powerpc: Set ARCH_HAS_STRICT_MODULE_RWX Russell Currey 2020-03-10 1:03 ` Russell Currey 2020-03-10 1:03 ` [PATCH v6 5/7] powerpc/configs: Enable STRICT_MODULE_RWX in skiroot_defconfig Russell Currey 2020-03-10 1:03 ` Russell Currey 2020-03-10 1:03 ` [PATCH v6 6/7] powerpc/mm: implement set_memory_attr() Russell Currey 2020-03-10 1:03 ` Russell Currey 2020-03-11 6:09 ` Daniel Axtens 2020-03-11 6:09 ` Daniel Axtens 2020-03-10 1:03 ` Russell Currey [this message] 2020-03-10 1:03 ` [PATCH v6 7/7] powerpc/32: use set_memory_attr() Russell Currey
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