| Message ID | 43df611d1c7b7ac16b181fb819f5d886daa31bad.1715952103.git.oleksii.kurochko@gmail.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | Enable build of full Xen for RISC-V | expand |
On 17.05.2024 15:54, Oleksii Kurochko wrote: > To avoid the compilation error below, it is needed to update to places > in common/page_alloc.c where flsl() is used as now flsl() returns unsigned int: > > ./include/xen/kernel.h:18:21: error: comparison of distinct pointer types lacks a cast [-Werror] > 18 | (void) (&_x == &_y); \ > | ^~ > common/page_alloc.c:1843:34: note: in expansion of macro 'min' > 1843 | unsigned int inc_order = min(MAX_ORDER, flsl(e - s) - 1); > > generic_fls{l} was used instead of __builtin_clz{l}(x) as if x is 0, > the result in undefined. > > The prototype of the per-architecture fls{l}() functions was changed to > return 'unsigned int' to align with the generic implementation of these > functions and avoid introducing signed/unsigned mismatches. > > Signed-off-by: Oleksii Kurochko <oleksii.kurochko@gmail.com> > --- > The patch is almost independent from Andrew's patch series > ( https://lore.kernel.org/xen-devel/20240313172716.2325427-1-andrew.cooper3@citrix.com/T/#t) > except test_fls() function which IMO can be merged as a separate patch after Andrew's patch > will be fully ready. If there wasn't this dependency (I don't think it's "almost independent"), I'd be offering R-b with again one nit below. > --- a/xen/arch/x86/include/asm/bitops.h > +++ b/xen/arch/x86/include/asm/bitops.h > @@ -425,20 +425,21 @@ static always_inline unsigned int arch_ffsl(unsigned long x) > * > * This is defined the same way as ffs. > */ > -static inline int flsl(unsigned long x) > +static always_inline unsigned int arch_flsl(unsigned long x) > { > - long r; > + unsigned long r; > > asm ( "bsr %1,%0\n\t" > "jnz 1f\n\t" > "mov $-1,%0\n" > "1:" : "=r" (r) : "rm" (x)); > - return (int)r+1; > + return (unsigned int)r+1; Since you now touch this, you'd better tidy it at the same time: return r + 1; (i.e. style and no need for a cast). Jan
On Tue, 2024-05-21 at 13:18 +0200, Jan Beulich wrote: > On 17.05.2024 15:54, Oleksii Kurochko wrote: > > To avoid the compilation error below, it is needed to update to > > places > > in common/page_alloc.c where flsl() is used as now flsl() returns > > unsigned int: > > > > ./include/xen/kernel.h:18:21: error: comparison of distinct pointer > > types lacks a cast [-Werror] > > 18 | (void) (&_x == &_y); \ > > | ^~ > > common/page_alloc.c:1843:34: note: in expansion of macro 'min' > > 1843 | unsigned int inc_order = min(MAX_ORDER, flsl(e > > - s) - 1); > > > > generic_fls{l} was used instead of __builtin_clz{l}(x) as if x is > > 0, > > the result in undefined. > > > > The prototype of the per-architecture fls{l}() functions was > > changed to > > return 'unsigned int' to align with the generic implementation of > > these > > functions and avoid introducing signed/unsigned mismatches. > > > > Signed-off-by: Oleksii Kurochko <oleksii.kurochko@gmail.com> > > --- > > The patch is almost independent from Andrew's patch series > > ( > > https://lore.kernel.org/xen-devel/20240313172716.2325427-1-andrew.cooper3@citrix.com/T/#t > > ) > > except test_fls() function which IMO can be merged as a separate > > patch after Andrew's patch > > will be fully ready. > > If there wasn't this dependency (I don't think it's "almost > independent"), > I'd be offering R-b with again one nit below. Aren't all changes, except those in xen/common/bitops.c, independent? I could move these changes in xen/common/bitops.c to a separate commit. I think it is safe to commit them ( an introduction of common logic for fls{l}() and tests ) separately since the CI tests have passed. ~ Oleksii > > > --- a/xen/arch/x86/include/asm/bitops.h > > +++ b/xen/arch/x86/include/asm/bitops.h > > @@ -425,20 +425,21 @@ static always_inline unsigned int > > arch_ffsl(unsigned long x) > > * > > * This is defined the same way as ffs. > > */ > > -static inline int flsl(unsigned long x) > > +static always_inline unsigned int arch_flsl(unsigned long x) > > { > > - long r; > > + unsigned long r; > > > > asm ( "bsr %1,%0\n\t" > > "jnz 1f\n\t" > > "mov $-1,%0\n" > > "1:" : "=r" (r) : "rm" (x)); > > - return (int)r+1; > > + return (unsigned int)r+1; > > Since you now touch this, you'd better tidy it at the same time: > > return r + 1; > > (i.e. style and no need for a cast). > > Jan
On 22.05.2024 09:37, Oleksii K. wrote: > On Tue, 2024-05-21 at 13:18 +0200, Jan Beulich wrote: >> On 17.05.2024 15:54, Oleksii Kurochko wrote: >>> To avoid the compilation error below, it is needed to update to >>> places >>> in common/page_alloc.c where flsl() is used as now flsl() returns >>> unsigned int: >>> >>> ./include/xen/kernel.h:18:21: error: comparison of distinct pointer >>> types lacks a cast [-Werror] >>> 18 | (void) (&_x == &_y); \ >>> | ^~ >>> common/page_alloc.c:1843:34: note: in expansion of macro 'min' >>> 1843 | unsigned int inc_order = min(MAX_ORDER, flsl(e >>> - s) - 1); >>> >>> generic_fls{l} was used instead of __builtin_clz{l}(x) as if x is >>> 0, >>> the result in undefined. >>> >>> The prototype of the per-architecture fls{l}() functions was >>> changed to >>> return 'unsigned int' to align with the generic implementation of >>> these >>> functions and avoid introducing signed/unsigned mismatches. >>> >>> Signed-off-by: Oleksii Kurochko <oleksii.kurochko@gmail.com> >>> --- >>> The patch is almost independent from Andrew's patch series >>> ( >>> https://lore.kernel.org/xen-devel/20240313172716.2325427-1-andrew.cooper3@citrix.com/T/#t >>> ) >>> except test_fls() function which IMO can be merged as a separate >>> patch after Andrew's patch >>> will be fully ready. >> >> If there wasn't this dependency (I don't think it's "almost >> independent"), >> I'd be offering R-b with again one nit below. > > Aren't all changes, except those in xen/common/bitops.c, independent? I > could move these changes in xen/common/bitops.c to a separate commit. I > think it is safe to commit them ( an introduction of common logic for > fls{l}() and tests ) separately since the CI tests have passed. Technically they might be, but contextually there are further conflicts. Just try "patch --dry-run" on top of a plain staging tree. You really need to settle, perhaps consulting Andrew, whether you want to go on top of his change, or ahead of it. I'm not willing to approve a patch that's presented one way but then is (kind of) expected to go in the other way. Jan
Hi, On 22/05/2024 09:15, Jan Beulich wrote: > On 22.05.2024 09:37, Oleksii K. wrote: >> On Tue, 2024-05-21 at 13:18 +0200, Jan Beulich wrote: >>> On 17.05.2024 15:54, Oleksii Kurochko wrote: >>>> To avoid the compilation error below, it is needed to update to >>>> places >>>> in common/page_alloc.c where flsl() is used as now flsl() returns >>>> unsigned int: >>>> >>>> ./include/xen/kernel.h:18:21: error: comparison of distinct pointer >>>> types lacks a cast [-Werror] >>>> 18 | (void) (&_x == &_y); \ >>>> | ^~ >>>> common/page_alloc.c:1843:34: note: in expansion of macro 'min' >>>> 1843 | unsigned int inc_order = min(MAX_ORDER, flsl(e >>>> - s) - 1); >>>> >>>> generic_fls{l} was used instead of __builtin_clz{l}(x) as if x is >>>> 0, >>>> the result in undefined. >>>> >>>> The prototype of the per-architecture fls{l}() functions was >>>> changed to >>>> return 'unsigned int' to align with the generic implementation of >>>> these >>>> functions and avoid introducing signed/unsigned mismatches. >>>> >>>> Signed-off-by: Oleksii Kurochko <oleksii.kurochko@gmail.com> >>>> --- >>>> The patch is almost independent from Andrew's patch series >>>> ( >>>> https://lore.kernel.org/xen-devel/20240313172716.2325427-1-andrew.cooper3@citrix.com/T/#t >>>> ) >>>> except test_fls() function which IMO can be merged as a separate >>>> patch after Andrew's patch >>>> will be fully ready. >>> >>> If there wasn't this dependency (I don't think it's "almost >>> independent"), >>> I'd be offering R-b with again one nit below. >> >> Aren't all changes, except those in xen/common/bitops.c, independent? I >> could move these changes in xen/common/bitops.c to a separate commit. I >> think it is safe to commit them ( an introduction of common logic for >> fls{l}() and tests ) separately since the CI tests have passed. > > Technically they might be, but contextually there are further conflicts. > Just try "patch --dry-run" on top of a plain staging tree. You really > need to settle, perhaps consulting Andrew, whether you want to go on top > of his change, or ahead of it. I'm not willing to approve a patch that's > presented one way but then is (kind of) expected to go in the other way. I agree with what Jan wrote. I don't have any strong opinion on which order they should be merged. But, if your series is intended to be merged before Andrew's one then please rebase to vanilla staging. I looked at the rest of the patch and it LGTM. Cheers,
diff --git a/xen/arch/arm/include/asm/arm32/bitops.h b/xen/arch/arm/include/asm/arm32/bitops.h index d0309d47c1..9ee96f568b 100644 --- a/xen/arch/arm/include/asm/arm32/bitops.h +++ b/xen/arch/arm/include/asm/arm32/bitops.h @@ -1,7 +1,7 @@ #ifndef _ARM_ARM32_BITOPS_H #define _ARM_ARM32_BITOPS_H -#define flsl fls +#define arch_flsl arch_fls /* * Little endian assembly bitops. nr = 0 -> byte 0 bit 0. diff --git a/xen/arch/arm/include/asm/arm64/bitops.h b/xen/arch/arm/include/asm/arm64/bitops.h index 906d84e5f2..d942077392 100644 --- a/xen/arch/arm/include/asm/arm64/bitops.h +++ b/xen/arch/arm/include/asm/arm64/bitops.h @@ -1,17 +1,15 @@ #ifndef _ARM_ARM64_BITOPS_H #define _ARM_ARM64_BITOPS_H -static inline int flsl(unsigned long x) +static always_inline unsigned int arch_flsl(unsigned long x) { uint64_t ret; - if (__builtin_constant_p(x)) - return generic_flsl(x); - asm("clz\t%0, %1" : "=r" (ret) : "r" (x)); return BITS_PER_LONG - ret; } +#define arch_flsl arch_flsl /* Based on linux/include/asm-generic/bitops/find.h */ diff --git a/xen/arch/arm/include/asm/bitops.h b/xen/arch/arm/include/asm/bitops.h index 8e16335e76..f428cf8338 100644 --- a/xen/arch/arm/include/asm/bitops.h +++ b/xen/arch/arm/include/asm/bitops.h @@ -78,17 +78,14 @@ bool clear_mask16_timeout(uint16_t mask, volatile void *p, * the clz instruction for much better code efficiency. */ -static inline int fls(unsigned int x) +static always_inline unsigned int arch_fls(unsigned int x) { - int ret; - - if (__builtin_constant_p(x)) - return generic_fls(x); + unsigned int ret; asm("clz\t%"__OP32"0, %"__OP32"1" : "=r" (ret) : "r" (x)); return 32 - ret; } - +#define arch_fls arch_fls #define arch_ffs(x) ({ unsigned int __t = (x); fls(ISOLATE_LSB(__t)); }) #define arch_ffsl(x) ({ unsigned long __t = (x); flsl(ISOLATE_LSB(__t)); }) diff --git a/xen/arch/ppc/include/asm/bitops.h b/xen/arch/ppc/include/asm/bitops.h index 049aa62b89..46154fc957 100644 --- a/xen/arch/ppc/include/asm/bitops.h +++ b/xen/arch/ppc/include/asm/bitops.h @@ -119,9 +119,6 @@ static inline int test_and_set_bit(unsigned int nr, volatile void *addr) (volatile unsigned int *)addr + BITOP_WORD(nr)) != 0; } -#define flsl(x) generic_flsl(x) -#define fls(x) generic_fls(x) - /** * hweightN - returns the hamming weight of a N-bit word * @x: the word to weigh diff --git a/xen/arch/x86/include/asm/bitops.h b/xen/arch/x86/include/asm/bitops.h index 23f09fdb7a..17849fae97 100644 --- a/xen/arch/x86/include/asm/bitops.h +++ b/xen/arch/x86/include/asm/bitops.h @@ -425,20 +425,21 @@ static always_inline unsigned int arch_ffsl(unsigned long x) * * This is defined the same way as ffs. */ -static inline int flsl(unsigned long x) +static always_inline unsigned int arch_flsl(unsigned long x) { - long r; + unsigned long r; asm ( "bsr %1,%0\n\t" "jnz 1f\n\t" "mov $-1,%0\n" "1:" : "=r" (r) : "rm" (x)); - return (int)r+1; + return (unsigned int)r+1; } +#define arch_flsl arch_flsl -static inline int fls(unsigned int x) +static always_inline unsigned int arch_fls(unsigned int x) { - int r; + unsigned int r; asm ( "bsr %1,%0\n\t" "jnz 1f\n\t" @@ -446,6 +447,7 @@ static inline int fls(unsigned int x) "1:" : "=r" (r) : "rm" (x)); return r + 1; } +#define arch_fls arch_fls /** * hweightN - returns the hamming weight of a N-bit word diff --git a/xen/common/bitops.c b/xen/common/bitops.c index a8c32f6767..95bc47176b 100644 --- a/xen/common/bitops.c +++ b/xen/common/bitops.c @@ -62,9 +62,31 @@ static void test_ffs(void) CHECK(ffs64, (uint64_t)0x8000000000000000, 64); } +static void test_fls(void) +{ + /* unsigned int ffs(unsigned int) */ + CHECK(fls, 1, 1); + CHECK(fls, 3, 2); + CHECK(fls, 3U << 30, 32); + + /* unsigned int flsl(unsigned long) */ + CHECK(flsl, 1, 1); + CHECK(flsl, 1UL << (BITS_PER_LONG - 1), BITS_PER_LONG); +#if BITS_PER_LONG > 32 + CHECK(flsl, 3UL << 32, 34); +#endif + + /* unsigned int fls64(uint64_t) */ + CHECK(fls64, 1, 1); + CHECK(fls64, 0x00000000C0000000ULL, 32); + CHECK(fls64, 0x0000000180000000ULL, 33); + CHECK(fls64, 0xC000000000000000ULL, 64); +} + static int __init cf_check test_bitops(void) { test_ffs(); + test_fls(); return 0; } diff --git a/xen/common/page_alloc.c b/xen/common/page_alloc.c index be4ba3962a..eed6b2a901 100644 --- a/xen/common/page_alloc.c +++ b/xen/common/page_alloc.c @@ -1842,7 +1842,7 @@ static void _init_heap_pages(const struct page_info *pg, * Note that the value of ffsl() and flsl() starts from 1 so we need * to decrement it by 1. */ - unsigned int inc_order = min(MAX_ORDER, flsl(e - s) - 1); + unsigned int inc_order = min(MAX_ORDER + 0U, flsl(e - s) - 1); if ( s ) inc_order = min(inc_order, ffsl(s) - 1U); @@ -2266,7 +2266,7 @@ void __init xenheap_max_mfn(unsigned long mfn) ASSERT(!first_node_initialised); ASSERT(!xenheap_bits); BUILD_BUG_ON((PADDR_BITS - PAGE_SHIFT) >= BITS_PER_LONG); - xenheap_bits = min(flsl(mfn + 1) - 1 + PAGE_SHIFT, PADDR_BITS); + xenheap_bits = min(flsl(mfn + 1) - 1 + PAGE_SHIFT, PADDR_BITS + 0U); printk(XENLOG_INFO "Xen heap: %u bits\n", xenheap_bits); } diff --git a/xen/include/xen/bitops.h b/xen/include/xen/bitops.h index 6eeeff0117..59b8028894 100644 --- a/xen/include/xen/bitops.h +++ b/xen/include/xen/bitops.h @@ -200,6 +200,30 @@ static always_inline bool test_bit(int nr, const volatile void *addr) test_bit(nr, addr); \ }) +static always_inline __pure unsigned int fls(unsigned int x) +{ + if ( __builtin_constant_p(x) ) + return generic_fls(x); + +#ifndef arch_fls +#define arch_fls generic_fls +#endif + + return arch_fls(x); +} + +static always_inline __pure unsigned int flsl(unsigned long x) +{ + if ( __builtin_constant_p(x) ) + return generic_flsl(x); + +#ifndef arch_flsl +#define arch_flsl generic_flsl +#endif + + return arch_flsl(x); +} + /* * Find First Set bit. Bits are labelled from 1. */
To avoid the compilation error below, it is needed to update to places in common/page_alloc.c where flsl() is used as now flsl() returns unsigned int: ./include/xen/kernel.h:18:21: error: comparison of distinct pointer types lacks a cast [-Werror] 18 | (void) (&_x == &_y); \ | ^~ common/page_alloc.c:1843:34: note: in expansion of macro 'min' 1843 | unsigned int inc_order = min(MAX_ORDER, flsl(e - s) - 1); generic_fls{l} was used instead of __builtin_clz{l}(x) as if x is 0, the result in undefined. The prototype of the per-architecture fls{l}() functions was changed to return 'unsigned int' to align with the generic implementation of these functions and avoid introducing signed/unsigned mismatches. Signed-off-by: Oleksii Kurochko <oleksii.kurochko@gmail.com> --- The patch is almost independent from Andrew's patch series ( https://lore.kernel.org/xen-devel/20240313172716.2325427-1-andrew.cooper3@citrix.com/T/#t) except test_fls() function which IMO can be merged as a separate patch after Andrew's patch will be fully ready. --- Changes in V10: - update return type of arch_flsl() across arcitectures to 'unsigned int' to be aligned with return type of generic flsl() in xen/bitops.h. - switch inline to always_inline for arch_flsl() across architectures to be in sync with other similar changes. - define arch_flsl as arch_fls not just only fls. - update the commit message ( add information that per-arch fls{l)() protypes were changed ). --- Changes in V9: - update return type of fls and flsl() to unsigned int to be aligned with other bit ops. - update places where return value of fls() and flsl() is compared with int. - update the commit message. --- Changes in V8: - do proper rebase: back definition of fls{l} to the current patch. - drop the changes which removed ffz() in PPC. it should be done not in this patch. - add a message after Signed-off. --- Changes in V7: - Code style fixes --- Changes in V6: - new patch for the patch series. --- xen/arch/arm/include/asm/arm32/bitops.h | 2 +- xen/arch/arm/include/asm/arm64/bitops.h | 6 ++---- xen/arch/arm/include/asm/bitops.h | 9 +++------ xen/arch/ppc/include/asm/bitops.h | 3 --- xen/arch/x86/include/asm/bitops.h | 12 +++++++----- xen/common/bitops.c | 22 ++++++++++++++++++++++ xen/common/page_alloc.c | 4 ++-- xen/include/xen/bitops.h | 24 ++++++++++++++++++++++++ 8 files changed, 61 insertions(+), 21 deletions(-)