Messages in this thread | | | From | Marco Elver <> | Date | Tue, 2 Mar 2021 15:57:01 +0100 | Subject | Re: [PATCH 3/3] [v4] lib/vsprintf: no_hash_pointers prints all addresses as unhashed |
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On Tue, 2 Mar 2021 at 15:55, Geert Uytterhoeven <geert@linux-m68k.org> wrote: > > Hi Marco, > > On Tue, Mar 2, 2021 at 3:40 PM Marco Elver <elver@google.com> wrote: > > On Tue, 2 Mar 2021 at 15:35, Matthew Wilcox <willy@infradead.org> wrote: > > > On Tue, Mar 02, 2021 at 03:26:50PM +0100, Marco Elver wrote: > > > > +static const char no_hash_pointers_warning[9][55] __initconst = { > > > > + "******************************************************", > > > > + " NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE ", > > > > + " ", > > > > + " This system shows unhashed kernel memory addresses ", > > > > + " via the console, logs, and other interfaces. This ", > > > > + " might reduce the security of your system. ", > > > > + " If you see this message and you are not debugging ", > > > > + " the kernel, report this immediately to your system ", > > > > + " administrator! ", > > > > +}; > > > > + > > > > static int __init no_hash_pointers_enable(char *str) > > > > { > > > > + const int lines[] = { 0, 1, 2, 3, 4, 5, 2, 6, 7, 8, 2, 1, 0 }; > > > > + int i; > > > > + > > > > no_hash_pointers = true; > > > > > > > > - pr_warn("**********************************************************\n"); > > > > - pr_warn("** NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE **\n"); > > > > - pr_warn("** **\n"); > > > > - pr_warn("** This system shows unhashed kernel memory addresses **\n"); > > > > - pr_warn("** via the console, logs, and other interfaces. This **\n"); > > > > - pr_warn("** might reduce the security of your system. **\n"); > > > > - pr_warn("** **\n"); > > > > - pr_warn("** If you see this message and you are not debugging **\n"); > > > > - pr_warn("** the kernel, report this immediately to your system **\n"); > > > > - pr_warn("** administrator! **\n"); > > > > - pr_warn("** **\n"); > > > > - pr_warn("** NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE **\n"); > > > > - pr_warn("**********************************************************\n"); > > > > + for (i = 0; i < ARRAY_SIZE(lines); i++) > > > > + pr_warn("**%s**\n", no_hash_pointers_warning[lines[i]]); > > > > > > + for (i = 0; i < 3; i++) > > > + pr_warn("**%s**\n", no_hash_pointers_warning[lines[2 - i]]); > > > > Yeah, I had that before, but then wanted to deal with the blank line > > in the middle of the thing. So I just went with the lines array above, > > which seemed cleanest for dealing with the middle blank line and > > footer. Or maybe there's something even nicer I missed? :-) > > Gcc deduplicates the identical strings, so you don't have to go through > a double indirection at all?
In this case I think we do, because we're asking the compiler to create a giant array char[9][55]. If we had char*[9], then you're right, but in that case we would not benefit from __initconst for the majority of the data.
Thanks, -- Marco
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