Hello, Give me a day or so and I can do the following things: 1) Write you all a brand new standards-conforming strncpy in SH4 asm like this that is easier to read 2) Compile it with sh4-elf-GCC 9.2 3) Test it on a real SH4 (SH7750/SH7750R-like) The warning, if it shows up in my test, would likely then be a GCC thing--I have an idea of what it's doing, but I'll be sure after that. Unfortunately it's 4AM here on the other side of the world right now... -Karl -----Original Message----- From: Kuninori Morimoto <kuninori.morimoto.gx@xxxxxxxxxxx> To: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> Cc: Yoshinori Sato <ysato@xxxxxxxxxxxxxxxxxxxx>; Rich Felker <dalias@xxxxxxxx>; Linux-SH <linux-sh@xxxxxxxxxxxxxxx>; Linux-Renesas <linux-renesas-soc@xxxxxxxxxxxxxxx> Sent: Tue, Dec 17, 2019 3:51 am Subject: Re: can someone solve string_32.h issue for SH ? Hi Geert Cc Yoshinori-san > > --- a/arch/sh/include/asm/string_32.h > > +++ b/arch/sh/include/asm/string_32.h > > @@ -40,15 +40,15 @@ static inline char *strncpy(char *__dest, const > > char *__src, size_t __n) > > __asm__ __volatile__( > > "1:\n" > > "mov.b @%1+, %2\n\t" > > - "mov.b %2, @%0\n\t" > > + "mov.b %2, @%0+\n\t" > > "cmp/eq #0, %2\n\t" > > "bt/s 2f\n\t" > > - " cmp/eq %5,%1\n\t" > > + " cmp/eq %5,%0\n\t" > > "bf/s 1b\n\t" > > - " add #1, %0\n" > > + " nop\n" > > "2:" > > : "=r" (__dest), "=r" (__src), "=&z" (__dummy) > > - : "0" (__dest), "1" (__src), "r" (__src+__n) > > + : "0" (__dest), "1" (__src), "r" (__dest+__n) > > : "memory", "t"); > > > > return __xdest; > > > > Does this make sense? > > Can it be improved, by putting something useful in the delay slot? > > BTW, there seems to be a serious security issue with this strncpy() > implementation: while it never writes more than n bytes in the > destination buffer, it doesn't pad the destination buffer with zeroes if > the source string is shorter than the buffer size. This will leak > data. Yeah... I can only do is "Reporting issue" to SH ML, unfortunately... Thank you for your help !! Best regards --- Kuninori Morimoto
