From: Peter Zijlstra <peterz@infradead.org>
To: Igor Stoppa <igor.stoppa@gmail.com>
Cc: Mimi Zohar <zohar@linux.vnet.ibm.com>,
Kees Cook <keescook@chromium.org>,
Matthew Wilcox <willy@infradead.org>,
Dave Chinner <david@fromorbit.com>,
James Morris <jmorris@namei.org>,
Michal Hocko <mhocko@kernel.org>,
kernel-hardening@lists.openwall.com,
linux-integrity@vger.kernel.org,
linux-security-module@vger.kernel.org, igor.stoppa@huawei.com,
Dave Hansen <dave.hansen@linux.intel.com>,
Jonathan Corbet <corbet@lwn.net>,
Laura Abbott <labbott@redhat.com>,
Vlastimil Babka <vbabka@suse.cz>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Andrew Morton <akpm@linux-foundation.org>,
Pavel Tatashin <pasha.tatashin@oracle.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 02/17] prmem: write rare for static allocation
Date: Fri, 26 Oct 2018 11:41:05 +0200 [thread overview]
Message-ID: <20181026094105.GE3159@worktop.c.hoisthospitality.com> (raw)
In-Reply-To: <20181023213504.28905-3-igor.stoppa@huawei.com>
On Wed, Oct 24, 2018 at 12:34:49AM +0300, Igor Stoppa wrote:
> +static __always_inline
That's far too large for inline.
> +bool wr_memset(const void *dst, const int c, size_t n_bytes)
> +{
> + size_t size;
> + unsigned long flags;
> + uintptr_t d = (uintptr_t)dst;
> +
> + if (WARN(!__is_wr_after_init(dst, n_bytes), WR_ERR_RANGE_MSG))
> + return false;
> + while (n_bytes) {
> + struct page *page;
> + uintptr_t base;
> + uintptr_t offset;
> + uintptr_t offset_complement;
> +
> + local_irq_save(flags);
> + page = virt_to_page(d);
> + offset = d & ~PAGE_MASK;
> + offset_complement = PAGE_SIZE - offset;
> + size = min(n_bytes, offset_complement);
> + base = (uintptr_t)vmap(&page, 1, VM_MAP, PAGE_KERNEL);
> + if (WARN(!base, WR_ERR_PAGE_MSG)) {
> + local_irq_restore(flags);
> + return false;
> + }
> + memset((void *)(base + offset), c, size);
> + vunmap((void *)base);
BUG
> + d += size;
> + n_bytes -= size;
> + local_irq_restore(flags);
> + }
> + return true;
> +}
> +
> +static __always_inline
Similarly large
> +bool wr_memcpy(const void *dst, const void *src, size_t n_bytes)
> +{
> + size_t size;
> + unsigned long flags;
> + uintptr_t d = (uintptr_t)dst;
> + uintptr_t s = (uintptr_t)src;
> +
> + if (WARN(!__is_wr_after_init(dst, n_bytes), WR_ERR_RANGE_MSG))
> + return false;
> + while (n_bytes) {
> + struct page *page;
> + uintptr_t base;
> + uintptr_t offset;
> + uintptr_t offset_complement;
> +
> + local_irq_save(flags);
> + page = virt_to_page(d);
> + offset = d & ~PAGE_MASK;
> + offset_complement = PAGE_SIZE - offset;
> + size = (size_t)min(n_bytes, offset_complement);
> + base = (uintptr_t)vmap(&page, 1, VM_MAP, PAGE_KERNEL);
> + if (WARN(!base, WR_ERR_PAGE_MSG)) {
> + local_irq_restore(flags);
> + return false;
> + }
> + __write_once_size((void *)(base + offset), (void *)s, size);
> + vunmap((void *)base);
Similarly BUG.
> + d += size;
> + s += size;
> + n_bytes -= size;
> + local_irq_restore(flags);
> + }
> + return true;
> +}
> +static __always_inline
Guess what..
> +uintptr_t __wr_rcu_ptr(const void *dst_p_p, const void *src_p)
> +{
> + unsigned long flags;
> + struct page *page;
> + void *base;
> + uintptr_t offset;
> + const size_t size = sizeof(void *);
> +
> + if (WARN(!__is_wr_after_init(dst_p_p, size), WR_ERR_RANGE_MSG))
> + return (uintptr_t)NULL;
> + local_irq_save(flags);
> + page = virt_to_page(dst_p_p);
> + offset = (uintptr_t)dst_p_p & ~PAGE_MASK;
> + base = vmap(&page, 1, VM_MAP, PAGE_KERNEL);
> + if (WARN(!base, WR_ERR_PAGE_MSG)) {
> + local_irq_restore(flags);
> + return (uintptr_t)NULL;
> + }
> + rcu_assign_pointer((*(void **)(offset + (uintptr_t)base)), src_p);
> + vunmap(base);
Also still bug.
> + local_irq_restore(flags);
> + return (uintptr_t)src_p;
> +}
Also, I see an amount of duplication here that shows you're not nearly
lazy enough.
next prev parent reply other threads:[~2018-10-26 9:41 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20181023213504.28905-1-igor.stoppa@huawei.com>
2018-10-23 21:34 ` [PATCH 02/17] prmem: write rare for static allocation Igor Stoppa
2018-10-25 0:24 ` Dave Hansen
2018-10-29 18:03 ` Igor Stoppa
2018-10-26 9:41 ` Peter Zijlstra [this message]
2018-10-29 20:01 ` Igor Stoppa
2018-10-23 21:34 ` [PATCH 03/17] prmem: vmalloc support for dynamic allocation Igor Stoppa
2018-10-25 0:26 ` Dave Hansen
2018-10-29 18:07 ` Igor Stoppa
2018-10-23 21:34 ` [PATCH 04/17] prmem: " Igor Stoppa
2018-10-23 21:34 ` [PATCH 05/17] prmem: shorthands for write rare on common types Igor Stoppa
2018-10-25 0:28 ` Dave Hansen
2018-10-29 18:12 ` Igor Stoppa
2018-10-23 21:34 ` [PATCH 06/17] prmem: test cases for memory protection Igor Stoppa
2018-10-24 3:27 ` Randy Dunlap
2018-10-24 14:24 ` Igor Stoppa
2018-10-25 16:43 ` Dave Hansen
2018-10-29 18:16 ` Igor Stoppa
2018-10-23 21:34 ` [PATCH 07/17] prmem: lkdtm tests " Igor Stoppa
2018-10-23 21:34 ` [PATCH 08/17] prmem: struct page: track vmap_area Igor Stoppa
2018-10-24 3:12 ` Matthew Wilcox
2018-10-24 23:01 ` Igor Stoppa
2018-10-25 2:13 ` Matthew Wilcox
2018-10-29 18:21 ` Igor Stoppa
2018-10-23 21:34 ` [PATCH 09/17] prmem: hardened usercopy Igor Stoppa
2018-10-29 11:45 ` Chris von Recklinghausen
2018-10-29 18:24 ` Igor Stoppa
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