From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from foss.arm.com ([217.140.110.172]:37870 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726578AbgLBMRz (ORCPT ); Wed, 2 Dec 2020 07:17:55 -0500 Subject: Re: [RFC V2 2/3] arm64/mm: Define arch_get_mappable_range() References: <1606706992-26656-1-git-send-email-anshuman.khandual@arm.com> <1606706992-26656-3-git-send-email-anshuman.khandual@arm.com> <1861413c-fd23-f3e2-14f3-00feec6ff2fb@redhat.com> From: Anshuman Khandual Message-ID: <85975346-d5ae-d971-e50f-9c0b77649910@arm.com> Date: Wed, 2 Dec 2020 17:47:01 +0530 MIME-Version: 1.0 In-Reply-To: <1861413c-fd23-f3e2-14f3-00feec6ff2fb@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit List-ID: To: David Hildenbrand , linux-mm@kvack.org, akpm@linux-foundation.org Cc: linux-arm-kernel@lists.infradead.org, linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, Catalin Marinas , Will Deacon , Ard Biesheuvel , Mark Rutland On 12/2/20 2:56 PM, David Hildenbrand wrote: > On 30.11.20 04:29, Anshuman Khandual wrote: >> This overrides arch_get_mappable_range() on arm64 platform which will be >> used with recently added generic framework. It drops inside_linear_region() >> and subsequent check in arch_add_memory() which are no longer required. >> >> Cc: Catalin Marinas >> Cc: Will Deacon >> Cc: Ard Biesheuvel >> Cc: Mark Rutland >> Cc: David Hildenbrand >> Cc: linux-arm-kernel@lists.infradead.org >> Cc: linux-kernel@vger.kernel.org >> Signed-off-by: Anshuman Khandual >> --- >> arch/arm64/mm/mmu.c | 14 ++++++-------- >> 1 file changed, 6 insertions(+), 8 deletions(-) >> >> diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c >> index ca692a815731..49ec8f2838f2 100644 >> --- a/arch/arm64/mm/mmu.c >> +++ b/arch/arm64/mm/mmu.c >> @@ -1444,16 +1444,19 @@ static void __remove_pgd_mapping(pgd_t *pgdir, unsigned long start, u64 size) >> free_empty_tables(start, end, PAGE_OFFSET, PAGE_END); >> } >> >> -static bool inside_linear_region(u64 start, u64 size) >> +struct range arch_get_mappable_range(void) >> { >> + struct range memhp_range; >> + >> /* >> * Linear mapping region is the range [PAGE_OFFSET..(PAGE_END - 1)] >> * accommodating both its ends but excluding PAGE_END. Max physical >> * range which can be mapped inside this linear mapping range, must >> * also be derived from its end points. >> */ >> - return start >= __pa(_PAGE_OFFSET(vabits_actual)) && >> - (start + size - 1) <= __pa(PAGE_END - 1); >> + memhp_range.start = __pa(_PAGE_OFFSET(vabits_actual)); >> + memhp_range.end = __pa(PAGE_END - 1); >> + return memhp_range; >> } >> >> int arch_add_memory(int nid, u64 start, u64 size, >> @@ -1461,11 +1464,6 @@ int arch_add_memory(int nid, u64 start, u64 size, >> { >> int ret, flags = 0; >> >> - if (!inside_linear_region(start, size)) { >> - pr_err("[%llx %llx] is outside linear mapping region\n", start, start + size); >> - return -EINVAL; >> - } > As discussed, I think something like a VM_BUG_ON() here might makes > sense, indicating that we require the caller to validate upfront. Same > applies to the s390x variant. Sure, will do. > > Thanks! >