| Message ID | 20221006070257.11632-1-nikita.shubin@maquefel.me (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | riscv: fix multi-letter extension compare | expand |
On 6 Oct 2022, at 08:02, Nikita Shubin <nikita.shubin@maquefel.me> wrote: > > From: Nikita Shubin <n.shubin@yadro.com> > > Increment ext pointer to match letters after 'z' character, so it points > to actual extension name. > > Fixes: 4905ec2fb7e6 ("RISC-V: Add sscofpmf extension support") > Signed-off-by: Nikita Shubin <n.shubin@yadro.com> > --- > Hello Atish, > > Sorry to blame you, but i double checked this and i don't see a way > how extensions from device tree could be successfully matched with > encoded ones without incrementing the ext pointer or prepending > the encoded extensions with 'z' letter. > > I have no idea how this could slip through review - am i missing something ? > --- > arch/riscv/kernel/cpufeature.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c > index 3b5583db9d80..031546052dc0 100644 > --- a/arch/riscv/kernel/cpufeature.c > +++ b/arch/riscv/kernel/cpufeature.c > @@ -199,6 +199,7 @@ void __init riscv_fill_hwcap(void) > this_hwcap |= isa2hwcap[(unsigned char)(*ext)]; > set_bit(*ext - 'a', this_isa); > } else { > + ext++; > SET_ISA_EXT_MAP("sscofpmf", RISCV_ISA_EXT_SSCOFPMF); > SET_ISA_EXT_MAP("svpbmt", RISCV_ISA_EXT_SVPBMT); > SET_ISA_EXT_MAP("zicbom", RISCV_ISA_EXT_ZICBOM); This makes no sense. The single-letter prefix that’s part of the actual extension name is already in the string there, whether s or z. Your code means (a) you’d have to double up the prefix in the device tree (which is obviously wrong) (b) you could use s or z interchangeably as the first character (e.g. you’d make zzicbom and szicbom parsed as zicbom). Are you actually seeing a bug? Did you test this at all? This looks like you misunderstood code and wrote an untested patch for a bug you thought you saw. Jess > -- > 2.35.1 > > > _______________________________________________ > linux-riscv mailing list > linux-riscv@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-riscv
Hello Atish, My bad, i somehow decided that 'sscofpmf' should be 'zsscofpmf' in device tree, but it's 'Sscofpmf' actually. Sorry for noise please ignore this patch. On Thu, 6 Oct 2022 10:02:56 +0300 Nikita Shubin <nikita.shubin@maquefel.me> wrote: > From: Nikita Shubin <n.shubin@yadro.com> > > Increment ext pointer to match letters after 'z' character, so it > points to actual extension name. > > Fixes: 4905ec2fb7e6 ("RISC-V: Add sscofpmf extension support") > Signed-off-by: Nikita Shubin <n.shubin@yadro.com> > --- > Hello Atish, > > Sorry to blame you, but i double checked this and i don't see a way > how extensions from device tree could be successfully matched with > encoded ones without incrementing the ext pointer or prepending > the encoded extensions with 'z' letter. > > I have no idea how this could slip through review - am i missing > something ? --- > arch/riscv/kernel/cpufeature.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/arch/riscv/kernel/cpufeature.c > b/arch/riscv/kernel/cpufeature.c index 3b5583db9d80..031546052dc0 > 100644 --- a/arch/riscv/kernel/cpufeature.c > +++ b/arch/riscv/kernel/cpufeature.c > @@ -199,6 +199,7 @@ void __init riscv_fill_hwcap(void) > this_hwcap |= isa2hwcap[(unsigned > char)(*ext)]; set_bit(*ext - 'a', this_isa); > } else { > + ext++; > SET_ISA_EXT_MAP("sscofpmf", > RISCV_ISA_EXT_SSCOFPMF); SET_ISA_EXT_MAP("svpbmt", > RISCV_ISA_EXT_SVPBMT); SET_ISA_EXT_MAP("zicbom", > RISCV_ISA_EXT_ZICBOM);
diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c index 3b5583db9d80..031546052dc0 100644 --- a/arch/riscv/kernel/cpufeature.c +++ b/arch/riscv/kernel/cpufeature.c @@ -199,6 +199,7 @@ void __init riscv_fill_hwcap(void) this_hwcap |= isa2hwcap[(unsigned char)(*ext)]; set_bit(*ext - 'a', this_isa); } else { + ext++; SET_ISA_EXT_MAP("sscofpmf", RISCV_ISA_EXT_SSCOFPMF); SET_ISA_EXT_MAP("svpbmt", RISCV_ISA_EXT_SVPBMT); SET_ISA_EXT_MAP("zicbom", RISCV_ISA_EXT_ZICBOM);