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Received: from [177.45.63.19] (helo=[192.168.1.111]) by fanzine2.igalia.com with esmtpsa (Cipher TLS1.3:ECDHE_X25519__RSA_PSS_RSAE_SHA256__AES_128_GCM:128) (Exim) id 1qTAxZ-00FAcr-T1; Tue, 08 Aug 2023 02:52:30 +0200 Message-ID: Date: Mon, 7 Aug 2023 21:52:18 -0300 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 03/14] futex: Flag conversion Content-Language: en-US To: Peter Zijlstra Cc: linux-kernel@vger.kernel.org, mingo@redhat.com, dvhart@infradead.org, dave@stgolabs.net, tglx@linutronix.de, Andrew Morton , axboe@kernel.dk, urezki@gmail.com, hch@infradead.org, lstoakes@gmail.com, Arnd Bergmann , linux-api@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, malteskarupke@web.de References: <20230807121843.710612856@infradead.org> <20230807123322.952568452@infradead.org> From: =?UTF-8?Q?Andr=C3=A9_Almeida?= In-Reply-To: <20230807123322.952568452@infradead.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Rspamd-Queue-Id: A4FF840025 X-Rspam-User: X-Rspamd-Server: rspam05 X-Stat-Signature: 97mi3pbdaekrrijjfnzyupcykqs3u497 X-HE-Tag: 1691455968-874370 X-HE-Meta: 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 xmVzp78a bMvyyI8A3F0EVe49dN1QF08DypEHVa0N/OilEZpjzwe67yCIrDoxG+ctlOeNhGL1BziWL5hCePUAxiEY/YcxYcpMMdkjEJOtncV4QjPOfdkILLLGhYAhcnw50VMuRxnUxKzBqymbBHEcY2OZVl367ZolDNLJ3bgkBfi5CCeGaoC14c+1xC+wSTK7pS47tK4VH+xWRHN+vphooSX2aW1i5ijYbTEEXek8Sj//83w2m4tZyVojvIHYj1fbfZYNd0qebmQrPznw7uYx7ctCspyNLtEeM/iZLswUM3xIn5/NzgiCVcnKJd0k7pEXnsi5GADHn4UCksvEWo/dFncFRQrKTlOQTCG9fKdCfc1YjCIVTEqCwTFNvVjmwOaGEqETaOLsDXk9nDF8BkbwQCeCGEW/K2A6xLu72QZxJHWkvFw2M42SM6rs= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Em 07/08/2023 09:18, Peter Zijlstra escreveu: > Futex has 3 sets of flags: > > - legacy futex op bits > - futex2 flags > - internal flags > > Add a few helpers to convert from the API flags into the internal > flags. > > Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: André Almeida > --- > kernel/futex/futex.h | 63 +++++++++++++++++++++++++++++++++++++++++++++--- > kernel/futex/syscalls.c | 24 ++++++------------ > kernel/futex/waitwake.c | 4 +-- > 3 files changed, 71 insertions(+), 20 deletions(-) > > --- a/kernel/futex/futex.h > +++ b/kernel/futex/futex.h > @@ -5,6 +5,7 @@ > #include > #include > #include > +#include > > #ifdef CONFIG_PREEMPT_RT > #include > @@ -16,8 +17,15 @@ > * Futex flags used to encode options to functions and preserve them across > * restarts. > */ > +#define FLAGS_SIZE_8 0x00 > +#define FLAGS_SIZE_16 0x01 > +#define FLAGS_SIZE_32 0x02 > +#define FLAGS_SIZE_64 0x03 > + Minor nit: for consistent, I would go with SIZE_U8, instead of SIZE_8 > +#define FLAGS_SIZE_MASK 0x03 > + > #ifdef CONFIG_MMU > -# define FLAGS_SHARED 0x01 > +# define FLAGS_SHARED 0x10 > #else > /* > * NOMMU does not have per process address space. Let the compiler optimize > @@ -25,8 +33,57 @@ > */ > # define FLAGS_SHARED 0x00 > #endif > -#define FLAGS_CLOCKRT 0x02 > -#define FLAGS_HAS_TIMEOUT 0x04 > +#define FLAGS_CLOCKRT 0x20 > +#define FLAGS_HAS_TIMEOUT 0x40 > +#define FLAGS_NUMA 0x80 > + > +/* FUTEX_ to FLAGS_ */ > +static inline unsigned int futex_to_flags(unsigned int op) > +{ > + unsigned int flags = FLAGS_SIZE_32; > + > + if (!(op & FUTEX_PRIVATE_FLAG)) > + flags |= FLAGS_SHARED; > + > + if (op & FUTEX_CLOCK_REALTIME) > + flags |= FLAGS_CLOCKRT; > + > + return flags; > +} > + > +/* FUTEX2_ to FLAGS_ */ > +static inline unsigned int futex2_to_flags(unsigned int flags2) > +{ > + unsigned int flags = flags2 & FUTEX2_SIZE_MASK; > + > + if (!(flags2 & FUTEX2_PRIVATE)) > + flags |= FLAGS_SHARED; > + > + if (flags2 & FUTEX2_NUMA) > + flags |= FLAGS_NUMA; > + > + return flags; > +} > + > +static inline bool futex_flags_valid(unsigned int flags) > +{ > + /* Only 64bit futexes for 64bit code */ > + if (!IS_ENABLED(CONFIG_64BIT) || in_compat_syscall()) { > + if ((flags & FLAGS_SIZE_MASK) == FLAGS_SIZE_64) > + return false; > + } > + > + /* Only 32bit futexes are implemented -- for now */ > + if ((flags & FLAGS_SIZE_MASK) != FLAGS_SIZE_32) > + return false; > + > + return true; > +} > + > +static inline unsigned int futex_size(unsigned int flags) > +{ > + return 1 << (flags & FLAGS_SIZE_MASK); > +} > > #ifdef CONFIG_FAIL_FUTEX > extern bool should_fail_futex(bool fshared); > --- a/kernel/futex/syscalls.c > +++ b/kernel/futex/syscalls.c > @@ -1,6 +1,5 @@ > // SPDX-License-Identifier: GPL-2.0-or-later > > -#include > #include > #include > > @@ -85,15 +84,12 @@ SYSCALL_DEFINE3(get_robust_list, int, pi > long do_futex(u32 __user *uaddr, int op, u32 val, ktime_t *timeout, > u32 __user *uaddr2, u32 val2, u32 val3) > { > + unsigned int flags = futex_to_flags(op); > int cmd = op & FUTEX_CMD_MASK; > - unsigned int flags = 0; > > - if (!(op & FUTEX_PRIVATE_FLAG)) > - flags |= FLAGS_SHARED; > - > - if (op & FUTEX_CLOCK_REALTIME) { > - flags |= FLAGS_CLOCKRT; > - if (cmd != FUTEX_WAIT_BITSET && cmd != FUTEX_WAIT_REQUEUE_PI && > + if (flags & FLAGS_CLOCKRT) { > + if (cmd != FUTEX_WAIT_BITSET && > + cmd != FUTEX_WAIT_REQUEUE_PI && > cmd != FUTEX_LOCK_PI2) > return -ENOSYS; > } > @@ -201,21 +197,19 @@ static int futex_parse_waitv(struct fute > unsigned int i; > > for (i = 0; i < nr_futexes; i++) { > + unsigned int flags; > + > if (copy_from_user(&aux, &uwaitv[i], sizeof(aux))) > return -EFAULT; > > if ((aux.flags & ~FUTEX2_VALID_MASK) || aux.__reserved) > return -EINVAL; > > - if (!IS_ENABLED(CONFIG_64BIT) || in_compat_syscall()) { > - if ((aux.flags & FUTEX2_SIZE_MASK) == FUTEX2_SIZE_U64) > - return -EINVAL; > - } > - > - if ((aux.flags & FUTEX2_SIZE_MASK) != FUTEX2_SIZE_U32) > + flags = futex2_to_flags(aux.flags); > + if (!futex_flags_valid(flags)) > return -EINVAL; > > - futexv[i].w.flags = aux.flags; > + futexv[i].w.flags = flags; > futexv[i].w.val = aux.val; > futexv[i].w.uaddr = aux.uaddr; > futexv[i].q = futex_q_init; > --- a/kernel/futex/waitwake.c > +++ b/kernel/futex/waitwake.c > @@ -419,11 +419,11 @@ static int futex_wait_multiple_setup(str > */ > retry: > for (i = 0; i < count; i++) { > - if ((vs[i].w.flags & FUTEX_PRIVATE_FLAG) && retry) > + if (!(vs[i].w.flags & FLAGS_SHARED) && retry) > continue; > > ret = get_futex_key(u64_to_user_ptr(vs[i].w.uaddr), > - !(vs[i].w.flags & FUTEX_PRIVATE_FLAG), > + vs[i].w.flags & FLAGS_SHARED, > &vs[i].q.key, FUTEX_READ); > > if (unlikely(ret)) > >