Date: Fri, 18 Aug 2023 00:09:51 -0500 From: Kyle Evans <kevans@FreeBSD.org> To: "Bjoern A. Zeeb" <bz@FreeBSD.org>, src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Subject: Re: git: b80ea452375f - main - LinuxKPI: implement mul_u64_u64_div_u64() Message-ID: <ac12a699-b98a-de85-d459-e1e205280b40@FreeBSD.org> In-Reply-To: <202308180121.37I1LPTc024071@gitrepo.freebsd.org> References: <202308180121.37I1LPTc024071@gitrepo.freebsd.org>
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On 8/17/23 20:21, Bjoern A. Zeeb wrote: > The branch main has been updated by bz: > > URL: https://cgit.FreeBSD.org/src/commit/?id=b80ea452375f52a3ab7d82a9aef10da0d89985d9 > > commit b80ea452375f52a3ab7d82a9aef10da0d89985d9 > Author: Bjoern A. Zeeb <bz@FreeBSD.org> > AuthorDate: 2023-05-16 20:55:00 +0000 > Commit: Bjoern A. Zeeb <bz@FreeBSD.org> > CommitDate: 2023-08-18 01:20:39 +0000 > > LinuxKPI: implement mul_u64_u64_div_u64() > > Implement mul_u64_u64_div_u64() for an updated iwlwifi driver (though > we do not yet use it there; it is used for in-kernel ptp on wifi). > > Sponsored by: The FreeBSD Foundation > Submitted by: cperciva > MFC after: 10 days > Reviewed by: cperciva, dwmalone > Differential Revision: https://reviews.freebsd.org/D40120 This broke buildkernel on multiple architectures, it seems: https://ci.freebsd.org/tinderbox/ I've confirmed that reverting this commit fixes it. I'd be lying if I claimed to understand what's going on: 23:09:45 In file included from /usr/src/sys/dev/cxgbe/iw_cxgbe/device.c:39: 23:09:45 In file included from /usr/src/sys/compat/linuxkpi/common/include/linux/module.h:41: 23:09:45 In file included from /usr/src/sys/compat/linuxkpi/common/include/linux/kobject.h:34: 23:09:45 In file included from /usr/src/sys/compat/linuxkpi/common/include/linux/kernel.h:48: 23:09:45 In file included from /usr/src/sys/compat/linuxkpi/common/include/linux/sched.h:43: 23:09:45 In file included from /usr/src/sys/compat/linuxkpi/common/include/linux/hrtimer.h:32: 23:09:45 /usr/src/sys/compat/linuxkpi/common/include/linux/ktime.h:34:2: error: embedding a #include directive within macro arguments is not supported 23:09:45 #include <linux/jiffies.h> 23:09:45 ^ 23:09:45 /usr/src/sys/compat/linuxkpi/common/include/linux/math64.h:151:2: note: expansion of macro 'KASSERT' requested here 23:09:45 KASSERT(rem < z, ("%s: rem %ju >= z %ju\n", __func__, 23:09:45 ^ > --- > sys/compat/linuxkpi/common/include/linux/math64.h | 48 +++++++++++++++++++++++ > 1 file changed, 48 insertions(+) > > diff --git a/sys/compat/linuxkpi/common/include/linux/math64.h b/sys/compat/linuxkpi/common/include/linux/math64.h > index 1b00fd71e69f..e4ddce5b823e 100644 > --- a/sys/compat/linuxkpi/common/include/linux/math64.h > +++ b/sys/compat/linuxkpi/common/include/linux/math64.h > @@ -106,6 +106,54 @@ mul_u64_u32_div(uint64_t x, uint32_t y, uint32_t div) > return ((x / div) * y + (rem * y) / div); > } > > +static inline uint64_t > +mul_u64_u64_div_u64(uint64_t x, uint64_t y, uint64_t z) > +{ > + uint64_t res, rem; > + uint64_t x1, y1, y1z; > + > + res = rem = 0; > + x1 = x; > + y1z = y / z; > + y1 = y - y1z * z; > + > + /* > + * INVARIANT: x * y = res * z + rem + (y1 + y1z * z) * x1 > + * INVARIANT: y1 < z > + * INVARIANT: rem < z > + */ > + while (x1 > 0) { > + /* Handle low bit. */ > + if (x1 & 1) { > + x1 &= ~1; > + res += y1z; > + rem += y1; > + if ((rem < y1) || (rem >= z)) { > + res += 1; > + rem -= z; > + } > + } > + > + /* Shift x1 right and (y1 + y1z * z) left */ > + x1 >>= 1; > + if ((y1 * 2 < y1) || (y1 * 2 >= z)) { > + y1z = y1z * 2 + 1; > + y1 = y1 * 2 - z; > + } else { > + y1z *= 2; > + y1 *= 2; > + } > + } > + > + KASSERT(res * z + rem == x * y, ("%s: res %ju * z %ju + rem %ju != " > + "x %ju * y %ju", __func__, (uintmax_t)res, (uintmax_t)z, > + (uintmax_t)rem, (uintmax_t)x, (uintmax_t)y)); > + KASSERT(rem < z, ("%s: rem %ju >= z %ju\n", __func__, > + (uintmax_t)rem, (uintmax_t)z); > + > + return (res); > +} > + > static inline uint64_t > mul_u64_u32_shr(uint64_t x, uint32_t y, unsigned int shift) > {
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