From mboxrd@z Thu Jan 1 00:00:00 1970 From: lauraa@codeaurora.org (Laura Abbott) Date: Thu, 18 Dec 2014 14:48:10 -0800 Subject: [PATCH v0] ARMv8:mm:Support the DEBUG_PAGEALLOC In-Reply-To: <5490E123.8060904@linaro.org> References: <1414382488-916-1-git-send-email-zhichang.yuan@linaro.org> <544EC65E.4060009@codeaurora.org> <544F338A.2060600@linaro.org> <545168C9.4010206@codeaurora.org> <5490E123.8060904@linaro.org> Message-ID: <549359AA.8000006@codeaurora.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi, On 12/16/2014 5:49 PM, zhichang.yuan wrote: > Hi, Laura, > > > On 2014?10?30? 06:23, Laura Abbott wrote: >> On 10/27/2014 11:11 PM, zhichang.yuan wrote: >>> Hi, Laura, >>> >>> Thanks for your comments! >>> >>> >>> >> ... >>>>> +} >>>>> + >>>>> +void kernel_map_pages(struct page *page, int numpages, int enable) >>>>> +{ >>>>> + unsigned long start_addr, end_addr, addr; >>>>> + unsigned int level; >>>>> + >>>>> + pte_t *kpte; >>>>> + pteval_t old_pval, new_pval; >>>>> + >>>>> + int i, counter = 0; >>>>> + >>>>> + /*no highmem in ARMv8. */ >>>>> + addr = start_addr = (unsigned long)page_address(page); >>>>> + end_addr = start_addr + (numpages << PAGE_SHIFT); >>>>> + >>>>> + for (i = 0; i < numpages; addr += PAGE_SIZE, i++) { >>>>> + kpte = lookup_kaddress(addr, &level); >>>>> + /* >>>>> + * skip the memory holes. it is impossible if the input >>>>> + * parameter is valid. >>>>> + */ >>>>> + if (unlikely(!kpte || pte_none(*kpte))) { >>>>> + pr_err("Have no kernel linear mapping for 0x%0lx\n", addr); >>>>> + break; >>>>> + } >>>>> + >>>>> + if (level != PG_LEVEL_PAGE) { >>>>> + pr_err("Page entry for 0x%0lx is not PAGE LEVEL(%d)\n", >>>>> + addr, level); >>>>> + break; >>>>> + } >>>>> + >>>>> + old_pval = pte_val(*kpte); >>>>> + new_pval = (enable) ? (old_pval | PTE_VALID) : >>>>> + (old_pval & (~PTE_VALID)); >>>>> + if (unlikely(new_pval == old_pval)) { >>>>> + pr_warn("Page %s: same pte value at 0x%llx", >>>>> + (enable) ? "alloc" : "free", old_pval); >>>>> + continue; >>>>> + } >>>>> + >>>>> + set_pte(kpte, __pte(new_pval)); >>>>> + counter++; >>>>> + } >>>>> + >>>>> + if (counter) >>>>> + flush_tlb_kernel_range(start_addr, end_addr); >>>>> +} >>>> >>>> We already have some of this infrastructure to set page attributes >>>> in arch/arm64/mm/pageattr.c . We should be leveraging that for >>>> kernel_map_pages. >>>> >>> There is no pageattr.c for ARMv8. In X86, it exists. >>> Do you mean pmd_modify? >>> >> >> It was added to the kernel fairly recently >> >> https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=11d91a770f1fff44dafdf88d6089a3451f99c9b6 >> > > I browsed the pageattr.c, the functions which modify the page table entry attributes are good. But the base > function, change_memory_common, is limited for module memory space. It will make the relative functions are > not common. Can we do some changes on it? > > thanks, > -Zhichang > Yes, we should be able to adjust the bounds check there. The checks there are currently broken[1] anyways. I'd suggest changing it to something like this (to be folded in) ----8<---- From 8cc4cd7c72fc5ada01e44d943d00e0209c4304aa Mon Sep 17 00:00:00 2001 From: Laura Abbott Date: Thu, 18 Dec 2014 14:45:19 -0800 Subject: [PATCH] arm64: Update set memory_bounds_check Change-Id: Id2f308c44d49117aca18fe725f8f2f33ae6a5075 Signed-off-by: Laura Abbott --- arch/arm64/mm/pageattr.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/arch/arm64/mm/pageattr.c b/arch/arm64/mm/pageattr.c index bb0ea94..0516cbc 100644 --- a/arch/arm64/mm/pageattr.c +++ b/arch/arm64/mm/pageattr.c @@ -51,8 +51,13 @@ static int change_memory_common(unsigned long addr, int numpages, WARN_ON_ONCE(1); } - if (!is_module_address(start) || !is_module_address(end - 1)) - return -EINVAL; + if (!IS_ENABLED(DEBUG_PAGEALLOC)) { + if (start < MODULES_VADDR || start >= MODULES_END) + return -EINVAL; + + if (end < MODULES_VADDR || end >= MODULES_END) + return -EINVAL; + } data.set_mask = set_mask; data.clear_mask = clear_mask; -- [1] http://lists.infradead.org/pipermail/linux-arm-kernel/2014-December/307839.html -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation