| Message ID | 20190415083605.2560074-4-arnd@arndb.de |
|---|---|
| State | New |
| Headers | show |
| Series | [v2,1/4] s390: only build for new CPUs with clang | expand |
On Mon, Apr 15, 2019 at 1:37 AM Arnd Bergmann <arnd@arndb.de> wrote: > > The arch/s390/boot directory is built with its own set of compiler > options that does not include -Wno-pointer-sign like the rest of > the kernel does, this causes a lot of harmess but correct warnings s/harmess/harmless/ > when building with clang. > > For the atomics, we can add type casts to avoid the warnings, for > everything else the easiest way is to slightly adapt the types > to be more consistent. > > Signed-off-by: Arnd Bergmann <arnd@arndb.de> > --- > arch/s390/boot/ipl_parm.c | 2 +- > arch/s390/include/asm/bitops.h | 12 ++++++------ > arch/s390/include/asm/ebcdic.h | 2 +- > arch/s390/include/asm/lowcore.h | 2 +- > drivers/s390/char/sclp.h | 4 ++-- > 5 files changed, 11 insertions(+), 11 deletions(-) > > diff --git a/arch/s390/boot/ipl_parm.c b/arch/s390/boot/ipl_parm.c > index 36beb56de021..3f2f0a9f1dad 100644 > --- a/arch/s390/boot/ipl_parm.c > +++ b/arch/s390/boot/ipl_parm.c > @@ -51,7 +51,7 @@ void store_ipl_parmblock(void) > early_ipl_block_valid = 1; > } > > -static size_t scpdata_length(const char *buf, size_t count) > +static size_t scpdata_length(const u8 *buf, size_t count) > { > while (count) { > if (buf[count - 1] != '\0' && buf[count - 1] != ' ') > diff --git a/arch/s390/include/asm/bitops.h b/arch/s390/include/asm/bitops.h > index d1f8a4d94cca..9900d655014c 100644 > --- a/arch/s390/include/asm/bitops.h > +++ b/arch/s390/include/asm/bitops.h > @@ -73,7 +73,7 @@ static inline void set_bit(unsigned long nr, volatile unsigned long *ptr) > } > #endif > mask = 1UL << (nr & (BITS_PER_LONG - 1)); > - __atomic64_or(mask, addr); > + __atomic64_or(mask, (long *)addr); > } > > static inline void clear_bit(unsigned long nr, volatile unsigned long *ptr) > @@ -94,7 +94,7 @@ static inline void clear_bit(unsigned long nr, volatile unsigned long *ptr) > } > #endif > mask = ~(1UL << (nr & (BITS_PER_LONG - 1))); > - __atomic64_and(mask, addr); > + __atomic64_and(mask, (long *)addr); > } > > static inline void change_bit(unsigned long nr, volatile unsigned long *ptr) > @@ -115,7 +115,7 @@ static inline void change_bit(unsigned long nr, volatile unsigned long *ptr) > } > #endif > mask = 1UL << (nr & (BITS_PER_LONG - 1)); > - __atomic64_xor(mask, addr); > + __atomic64_xor(mask, (long *)addr); > } > > static inline int > @@ -125,7 +125,7 @@ test_and_set_bit(unsigned long nr, volatile unsigned long *ptr) > unsigned long old, mask; > > mask = 1UL << (nr & (BITS_PER_LONG - 1)); > - old = __atomic64_or_barrier(mask, addr); > + old = __atomic64_or_barrier(mask, (long *)addr); > return (old & mask) != 0; > } > > @@ -136,7 +136,7 @@ test_and_clear_bit(unsigned long nr, volatile unsigned long *ptr) > unsigned long old, mask; > > mask = ~(1UL << (nr & (BITS_PER_LONG - 1))); > - old = __atomic64_and_barrier(mask, addr); > + old = __atomic64_and_barrier(mask, (long *)addr); > return (old & ~mask) != 0; > } > > @@ -147,7 +147,7 @@ test_and_change_bit(unsigned long nr, volatile unsigned long *ptr) > unsigned long old, mask; > > mask = 1UL << (nr & (BITS_PER_LONG - 1)); > - old = __atomic64_xor_barrier(mask, addr); > + old = __atomic64_xor_barrier(mask, (long *)addr); Thanks for the follow up. This hunk and above all LGTM. > return (old & mask) != 0; > } > > diff --git a/arch/s390/include/asm/ebcdic.h b/arch/s390/include/asm/ebcdic.h > index 29441beb92e6..d3ce6adacb10 100644 > --- a/arch/s390/include/asm/ebcdic.h > +++ b/arch/s390/include/asm/ebcdic.h > @@ -20,7 +20,7 @@ extern __u8 _ebc_tolower[256]; /* EBCDIC -> lowercase */ > extern __u8 _ebc_toupper[256]; /* EBCDIC -> uppercase */ > > static inline void > -codepage_convert(const __u8 *codepage, volatile __u8 * addr, unsigned long nr) > +codepage_convert(const __u8 *codepage, volatile char* addr, unsigned long nr) > { > if (nr-- <= 0) > return; There are many call sites of ASCEBC which is defined in terms of this function. Do they all use `char*`? grep shows an explicit cast to `unsigned char*` in drivers/s390/char/tape_std.c for example. > diff --git a/arch/s390/include/asm/lowcore.h b/arch/s390/include/asm/lowcore.h > index cc0947e08b6f..f3a637afd485 100644 > --- a/arch/s390/include/asm/lowcore.h > +++ b/arch/s390/include/asm/lowcore.h > @@ -128,7 +128,7 @@ struct lowcore { > /* SMP info area */ > __u32 cpu_nr; /* 0x0398 */ > __u32 softirq_pending; /* 0x039c */ > - __u32 preempt_count; /* 0x03a0 */ > + __s32 preempt_count; /* 0x03a0 */ This change is less obvious. Do you still have the warning for that this hunk fixes? > __u32 spinlock_lockval; /* 0x03a4 */ > __u32 spinlock_index; /* 0x03a8 */ > __u32 fpu_flags; /* 0x03ac */ > diff --git a/drivers/s390/char/sclp.h b/drivers/s390/char/sclp.h > index 367e9d384d85..5918479ffa0e 100644 > --- a/drivers/s390/char/sclp.h > +++ b/drivers/s390/char/sclp.h > @@ -365,14 +365,14 @@ sclp_ascebc(unsigned char ch) > > /* translate string from EBCDIC to ASCII */ > static inline void > -sclp_ebcasc_str(unsigned char *str, int nr) > +sclp_ebcasc_str(char *str, int nr) > { > (MACHINE_IS_VM) ? EBCASC(str, nr) : EBCASC_500(str, nr); > } > > /* translate string from ASCII to EBCDIC */ > static inline void > -sclp_ascebc_str(unsigned char *str, int nr) > +sclp_ascebc_str(char *str, int nr) > { > (MACHINE_IS_VM) ? ASCEBC(str, nr) : ASCEBC_500(str, nr); > } > -- > 2.20.0 > -- Thanks, ~Nick Desaulniers
On Mon, Apr 22, 2019 at 7:52 PM 'Nick Desaulniers' via Clang Built Linux <clang-built-linux@googlegroups.com> wrote: > > @@ -20,7 +20,7 @@ extern __u8 _ebc_tolower[256]; /* EBCDIC -> lowercase */ > > extern __u8 _ebc_toupper[256]; /* EBCDIC -> uppercase */ > > > > static inline void > > -codepage_convert(const __u8 *codepage, volatile __u8 * addr, unsigned long nr) > > +codepage_convert(const __u8 *codepage, volatile char* addr, unsigned long nr) > > { > > if (nr-- <= 0) > > return; > > There are many call sites of ASCEBC which is defined in terms of this > function. Do they all use `char*`? grep shows an explicit cast to > `unsigned char*` in drivers/s390/char/tape_std.c for example. Generally speaking, the kernel is full of Wpointer-sign warnings, that's why this warning is disabled in the top-level Makefile by default. My patch fixes the ones in the s390 boot code that is not built with those default flags, but I made no attempt to fix the rest of the kernel. Fun fact: on most architectures, 'char' is signed, but on s390 and 32-bit arm it is unsigned. The compiler treats 'char', 'unsigned char' and 'signed char' as three distinct types here for that reason. > > diff --git a/arch/s390/include/asm/lowcore.h b/arch/s390/include/asm/lowcore.h > > index cc0947e08b6f..f3a637afd485 100644 > > --- a/arch/s390/include/asm/lowcore.h > > +++ b/arch/s390/include/asm/lowcore.h > > @@ -128,7 +128,7 @@ struct lowcore { > > /* SMP info area */ > > __u32 cpu_nr; /* 0x0398 */ > > __u32 softirq_pending; /* 0x039c */ > > - __u32 preempt_count; /* 0x03a0 */ > > + __s32 preempt_count; /* 0x03a0 */ > > This change is less obvious. Do you still have the warning for that > this hunk fixes? I can't find it now, but there are multiple users that would cause this, like: static inline void preempt_count_set(int pc) { int old, new; do { old = READ_ONCE(S390_lowcore.preempt_count); new = (old & PREEMPT_NEED_RESCHED) | (pc & ~PREEMPT_NEED_RESCHED); } while (__atomic_cmpxchg(&S390_lowcore.preempt_count, old, new) != old); } Arnd
On Tue, Apr 23, 2019 at 1:06 AM Arnd Bergmann <arnd@arndb.de> wrote: > > On Mon, Apr 22, 2019 at 7:52 PM 'Nick Desaulniers' via Clang Built > Linux <clang-built-linux@googlegroups.com> wrote: > > > > @@ -20,7 +20,7 @@ extern __u8 _ebc_tolower[256]; /* EBCDIC -> lowercase */ > > > extern __u8 _ebc_toupper[256]; /* EBCDIC -> uppercase */ > > > > > > static inline void > > > -codepage_convert(const __u8 *codepage, volatile __u8 * addr, unsigned long nr) > > > +codepage_convert(const __u8 *codepage, volatile char* addr, unsigned long nr) > > > { > > > if (nr-- <= 0) > > > return; > > > > There are many call sites of ASCEBC which is defined in terms of this > > function. Do they all use `char*`? grep shows an explicit cast to > > `unsigned char*` in drivers/s390/char/tape_std.c for example. > > Generally speaking, the kernel is full of Wpointer-sign warnings, that's why > this warning is disabled in the top-level Makefile by default. My patch fixes > the ones in the s390 boot code that is not built with those default flags, but > I made no attempt to fix the rest of the kernel. Right, sorry, I forgot about that. This patch looks good to me. Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> > > Fun fact: on most architectures, 'char' is signed, but on s390 and 32-bit > arm it is unsigned. The compiler treats 'char', 'unsigned char' and > 'signed char' > as three distinct types here for that reason. I think I recall reading about that in: https://www.amazon.com/ARM-System-Developers-Guide-Architecture/dp/1558608745 (I'll try to dig it up and post what the explanation was). -- Thanks, ~Nick Desaulniers
On Mon, Apr 15, 2019 at 10:35:54AM +0200, Arnd Bergmann wrote: > The arch/s390/boot directory is built with its own set of compiler > options that does not include -Wno-pointer-sign like the rest of > the kernel does, this causes a lot of harmess but correct warnings > when building with clang. > > For the atomics, we can add type casts to avoid the warnings, for > everything else the easiest way is to slightly adapt the types > to be more consistent. > > Signed-off-by: Arnd Bergmann <arnd@arndb.de> > --- > arch/s390/boot/ipl_parm.c | 2 +- > arch/s390/include/asm/bitops.h | 12 ++++++------ > arch/s390/include/asm/ebcdic.h | 2 +- > arch/s390/include/asm/lowcore.h | 2 +- > drivers/s390/char/sclp.h | 4 ++-- > 5 files changed, 11 insertions(+), 11 deletions(-) Applied, with typo fix and a simple coding style issue. Thanks!
diff --git a/arch/s390/boot/ipl_parm.c b/arch/s390/boot/ipl_parm.c index 36beb56de021..3f2f0a9f1dad 100644 --- a/arch/s390/boot/ipl_parm.c +++ b/arch/s390/boot/ipl_parm.c @@ -51,7 +51,7 @@ void store_ipl_parmblock(void) early_ipl_block_valid = 1; } -static size_t scpdata_length(const char *buf, size_t count) +static size_t scpdata_length(const u8 *buf, size_t count) { while (count) { if (buf[count - 1] != '\0' && buf[count - 1] != ' ') diff --git a/arch/s390/include/asm/bitops.h b/arch/s390/include/asm/bitops.h index d1f8a4d94cca..9900d655014c 100644 --- a/arch/s390/include/asm/bitops.h +++ b/arch/s390/include/asm/bitops.h @@ -73,7 +73,7 @@ static inline void set_bit(unsigned long nr, volatile unsigned long *ptr) } #endif mask = 1UL << (nr & (BITS_PER_LONG - 1)); - __atomic64_or(mask, addr); + __atomic64_or(mask, (long *)addr); } static inline void clear_bit(unsigned long nr, volatile unsigned long *ptr) @@ -94,7 +94,7 @@ static inline void clear_bit(unsigned long nr, volatile unsigned long *ptr) } #endif mask = ~(1UL << (nr & (BITS_PER_LONG - 1))); - __atomic64_and(mask, addr); + __atomic64_and(mask, (long *)addr); } static inline void change_bit(unsigned long nr, volatile unsigned long *ptr) @@ -115,7 +115,7 @@ static inline void change_bit(unsigned long nr, volatile unsigned long *ptr) } #endif mask = 1UL << (nr & (BITS_PER_LONG - 1)); - __atomic64_xor(mask, addr); + __atomic64_xor(mask, (long *)addr); } static inline int @@ -125,7 +125,7 @@ test_and_set_bit(unsigned long nr, volatile unsigned long *ptr) unsigned long old, mask; mask = 1UL << (nr & (BITS_PER_LONG - 1)); - old = __atomic64_or_barrier(mask, addr); + old = __atomic64_or_barrier(mask, (long *)addr); return (old & mask) != 0; } @@ -136,7 +136,7 @@ test_and_clear_bit(unsigned long nr, volatile unsigned long *ptr) unsigned long old, mask; mask = ~(1UL << (nr & (BITS_PER_LONG - 1))); - old = __atomic64_and_barrier(mask, addr); + old = __atomic64_and_barrier(mask, (long *)addr); return (old & ~mask) != 0; } @@ -147,7 +147,7 @@ test_and_change_bit(unsigned long nr, volatile unsigned long *ptr) unsigned long old, mask; mask = 1UL << (nr & (BITS_PER_LONG - 1)); - old = __atomic64_xor_barrier(mask, addr); + old = __atomic64_xor_barrier(mask, (long *)addr); return (old & mask) != 0; } diff --git a/arch/s390/include/asm/ebcdic.h b/arch/s390/include/asm/ebcdic.h index 29441beb92e6..d3ce6adacb10 100644 --- a/arch/s390/include/asm/ebcdic.h +++ b/arch/s390/include/asm/ebcdic.h @@ -20,7 +20,7 @@ extern __u8 _ebc_tolower[256]; /* EBCDIC -> lowercase */ extern __u8 _ebc_toupper[256]; /* EBCDIC -> uppercase */ static inline void -codepage_convert(const __u8 *codepage, volatile __u8 * addr, unsigned long nr) +codepage_convert(const __u8 *codepage, volatile char* addr, unsigned long nr) { if (nr-- <= 0) return; diff --git a/arch/s390/include/asm/lowcore.h b/arch/s390/include/asm/lowcore.h index cc0947e08b6f..f3a637afd485 100644 --- a/arch/s390/include/asm/lowcore.h +++ b/arch/s390/include/asm/lowcore.h @@ -128,7 +128,7 @@ struct lowcore { /* SMP info area */ __u32 cpu_nr; /* 0x0398 */ __u32 softirq_pending; /* 0x039c */ - __u32 preempt_count; /* 0x03a0 */ + __s32 preempt_count; /* 0x03a0 */ __u32 spinlock_lockval; /* 0x03a4 */ __u32 spinlock_index; /* 0x03a8 */ __u32 fpu_flags; /* 0x03ac */ diff --git a/drivers/s390/char/sclp.h b/drivers/s390/char/sclp.h index 367e9d384d85..5918479ffa0e 100644 --- a/drivers/s390/char/sclp.h +++ b/drivers/s390/char/sclp.h @@ -365,14 +365,14 @@ sclp_ascebc(unsigned char ch) /* translate string from EBCDIC to ASCII */ static inline void -sclp_ebcasc_str(unsigned char *str, int nr) +sclp_ebcasc_str(char *str, int nr) { (MACHINE_IS_VM) ? EBCASC(str, nr) : EBCASC_500(str, nr); } /* translate string from ASCII to EBCDIC */ static inline void -sclp_ascebc_str(unsigned char *str, int nr) +sclp_ascebc_str(char *str, int nr) { (MACHINE_IS_VM) ? ASCEBC(str, nr) : ASCEBC_500(str, nr); }
The arch/s390/boot directory is built with its own set of compiler options that does not include -Wno-pointer-sign like the rest of the kernel does, this causes a lot of harmess but correct warnings when building with clang. For the atomics, we can add type casts to avoid the warnings, for everything else the easiest way is to slightly adapt the types to be more consistent. Signed-off-by: Arnd Bergmann <arnd@arndb.de> --- arch/s390/boot/ipl_parm.c | 2 +- arch/s390/include/asm/bitops.h | 12 ++++++------ arch/s390/include/asm/ebcdic.h | 2 +- arch/s390/include/asm/lowcore.h | 2 +- drivers/s390/char/sclp.h | 4 ++-- 5 files changed, 11 insertions(+), 11 deletions(-) -- 2.20.0