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bh=FGfHyiCN0aXermKd8RTGCSgYZKL3rHsRsRTObZ041wo=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=mNdJn3zmkTmCNxGecjiwtvRHJj7oJCaSwKIpuW/qFtGgP7A45tHhzqfSv7PPJa38z KOQfUaRtfPZiFIVGpCfrsgXPfly7uYS4W06tmOSccRNuhxcRdqb5WiII42K8WNEgwg AjlCgSYSIHOOd7Vwcdi5H7rf0YNayRqHbIB7VShpX8VC/EjTHEtkYhWNP0AoL6mrvv XbfOgwo3T1XW1oQsmew9LoAvIPxNbjZM1qFbMHStoJSzJ3kLoBgUFrCTXRTHs7ws7T XSpl+DgyE34JTayrOcRfPYTMBQxDxt/lfqhTKT5hE8ZSBaYDxXUiJxZgT/HQTqaa+X 3hp+zCPkrv3Fg== Date: Sun, 12 Mar 2023 11:35:29 +0200 From: Mike Rapoport To: Alexandre Ghiti Cc: Catalin Marinas , Will Deacon , Paul Walmsley , Palmer Dabbelt , Albert Ou , Rob Herring , Frank Rowand , Andrew Morton , Anup Patel , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org, devicetree@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH v7 2/4] mm: Introduce memblock_isolate_memory Message-ID: References: <20230310094539.764357-1-alexghiti@rivosinc.com> <20230310094539.764357-3-alexghiti@rivosinc.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230310094539.764357-3-alexghiti@rivosinc.com> X-Rspam-User: X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 7DC3210000D X-Stat-Signature: zakmbwf8ppbdhrbqqwjqiz6iq8z6s454 X-HE-Tag: 1678613749-8579 X-HE-Meta: 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 A3YJDyej k7VFTlRuZRYL2EBqRrn0r5W4MfKLNuGqPa5KtdSpWa3fSUxQSStEJx+gwB64vgIbcsYnjBLZ5mksfJ/aWyHMb311LQvrsAUgSnl7pVnIn5X0ZDUr9gIwvhQ8qifHuNxXzgVL1by2hAm6h8iwRQUwSrYArZlIw6ojtDjISiyKysCdKe79PwvAdffnEM4j28/cGkxI4vWV5Iv6yu4+qrclRf7R5057APyIzkGMBGla8ZL36baPuvm1bS/1JKvaabSaj3RO4Y9FnHcqsCuyF8YBr9UwPGJl73qGfRindMBZCtVrjlxo3YowQREqSBifI4RnWhKsuriea84yhrrPC3JIYZuuBZPywzLiHumJP0ofRfaxit3qKXwfnrWTXudS95J9Q0heyyltHzdwDK9dgpCBLSYU3/MCNLbdhM+OArZcoNiRKJnmQF8Kw/8wMH4Lysvdl+tdofiBYyDkFVMZ2hIoDkWPF/G2QpqsDmeQaPq/vYy74GBs= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Hi Alexandre, On Fri, Mar 10, 2023 at 10:45:37AM +0100, Alexandre Ghiti wrote: > This function allows to split a region in memblock.memory and will be > useful when setting up the linear mapping with STRICT_KERNEL_RWX: it > allows to isolate the kernel text/rodata and then avoid to map those > regions with a PUD/P4D/PGD. > > Signed-off-by: Alexandre Ghiti > --- > include/linux/memblock.h | 1 + > mm/memblock.c | 22 +++++++++++++++++++++- > 2 files changed, 22 insertions(+), 1 deletion(-) > > diff --git a/include/linux/memblock.h b/include/linux/memblock.h > index 50ad19662a32..2f7ef97c0da7 100644 > --- a/include/linux/memblock.h > +++ b/include/linux/memblock.h > @@ -125,6 +125,7 @@ int memblock_clear_hotplug(phys_addr_t base, phys_addr_t size); > int memblock_mark_mirror(phys_addr_t base, phys_addr_t size); > int memblock_mark_nomap(phys_addr_t base, phys_addr_t size); > int memblock_clear_nomap(phys_addr_t base, phys_addr_t size); > +int memblock_isolate_memory(phys_addr_t base, phys_addr_t size); > > void memblock_free_all(void); > void memblock_free(void *ptr, size_t size); > diff --git a/mm/memblock.c b/mm/memblock.c > index 25fd0626a9e7..d8cf1c9eccf0 100644 > --- a/mm/memblock.c > +++ b/mm/memblock.c > @@ -753,7 +753,8 @@ static int __init_memblock memblock_isolate_range(struct memblock_type *type, > int idx; > struct memblock_region *rgn; > > - *start_rgn = *end_rgn = 0; > + if (start_rgn && end_rgn) > + *start_rgn = *end_rgn = 0; Generally, it's possible that either start_rgn or end_rgn will be a valid pointer and this should be handled here and below. My preference, though would be to leave memblock_isolate_range() as is and have unused start_rgn and end_rgn in memblock_isolate_memory(). > > if (!size) > return 0; > @@ -795,6 +796,9 @@ static int __init_memblock memblock_isolate_range(struct memblock_type *type, > memblock_get_region_node(rgn), > rgn->flags); > } else { > + if (!end_rgn || !start_rgn) > + continue; > + > /* @rgn is fully contained, record it */ > if (!*end_rgn) > *start_rgn = idx; > @@ -805,6 +809,22 @@ static int __init_memblock memblock_isolate_range(struct memblock_type *type, > return 0; > } > > +/** > + * memblock_isolate_memory - isolate given range from memblock.memory I think it'd better to use "... range in memblock.memory" > + * @base: base of range to isolate > + * @size: size of range to isolate > + * > + * Call memblock_isolate_range on memblock.memory to isolate the given range. Please elaborate that isolate means that the range does not share regions with other ranges. > + * > + * Return: > + * 0 on success, -errno on failure. > + */ > + > +int __init_memblock memblock_isolate_memory(phys_addr_t base, phys_addr_t size) > +{ > + return memblock_isolate_range(&memblock.memory, base, size, NULL, NULL); > +} > + > static int __init_memblock memblock_remove_range(struct memblock_type *type, > phys_addr_t base, phys_addr_t size) > { > -- > 2.37.2 > -- Sincerely yours, Mike.