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Thu, 15 Sep 2022 05:45:55 GMT Received: from b06wcsmtp001.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id C643CA405B; Thu, 15 Sep 2022 05:45:55 +0000 (GMT) Received: from b06wcsmtp001.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 285D6A4054; Thu, 15 Sep 2022 05:45:55 +0000 (GMT) Received: from ozlabs.au.ibm.com (unknown [9.192.253.14]) by b06wcsmtp001.portsmouth.uk.ibm.com (Postfix) with ESMTP; Thu, 15 Sep 2022 05:45:55 +0000 (GMT) Received: from smtpclient.apple (unknown [9.192.255.87]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.au.ibm.com (Postfix) with ESMTPSA id 7E42C6010D; Thu, 15 Sep 2022 15:45:49 +1000 (AEST) Content-Type: text/plain; charset=utf-8 Mime-Version: 1.0 (Mac OS X Mail 16.0 \(3696.120.41.1.1\)) Subject: Re: [PATCH v4 10/20] powerpc: Use common syscall handler type From: Rohan McLure In-Reply-To: Date: Thu, 15 Sep 2022 15:45:48 +1000 Content-Transfer-Encoding: quoted-printable Message-Id: <6E8ADD7A-6122-4615-8BFC-C1104F13B283@linux.ibm.com> References: <20220824020548.62625-1-rmclure@linux.ibm.com> <20220824020548.62625-11-rmclure@linux.ibm.com> To: Nicholas Piggin X-Mailer: Apple Mail (2.3696.120.41.1.1) X-TM-AS-GCONF: 00 X-Proofpoint-GUID: Mvd2U8UvlsyWKB9RBFSfjfbxbDd8L2pZ X-Proofpoint-ORIG-GUID: v_RvpW8O4DBrwDeNwGPmCWh3QE0lz-uO X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.895,Hydra:6.0.528,FMLib:17.11.122.1 definitions=2022-09-15_02,2022-09-14_04,2022-06-22_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 clxscore=1015 suspectscore=0 phishscore=0 priorityscore=1501 mlxscore=0 malwarescore=0 impostorscore=0 lowpriorityscore=0 bulkscore=0 adultscore=0 mlxlogscore=999 spamscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2208220000 definitions=main-2209150028 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linuxppc-dev@lists.ozlabs.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" > On 12 Sep 2022, at 8:56 pm, Nicholas Piggin wrote: >=20 > On Wed Aug 24, 2022 at 12:05 PM AEST, Rohan McLure wrote: >> Cause syscall handlers to be typed as follows when called indirectly >> throughout the kernel. >>=20 >> typedef long (*syscall_fn)(unsigned long, unsigned long, unsigned = long, >> unsigned long, unsigned long, unsigned = long); >=20 > The point is... better type checking? >=20 >>=20 >> Since both 32 and 64-bit abis allow for at least the first six >> machine-word length parameters to a function to be passed by = registers, >> even handlers which admit fewer than six parameters may be viewed as >> having the above type. >>=20 >> Fixup comparisons in VDSO to avoid pointer-integer comparison. = Introduce >> explicit cast on systems with SPUs. >>=20 >> Signed-off-by: Rohan McLure >> --- >> V1 -> V2: New patch. >> V2 -> V3: Remove unnecessary cast from const syscall_fn to syscall_fn >> --- >> arch/powerpc/include/asm/syscall.h | 7 +++++-- >> arch/powerpc/include/asm/syscalls.h | 1 + >> arch/powerpc/kernel/systbl.c | 6 +++--- >> arch/powerpc/kernel/vdso.c | 4 ++-- >> arch/powerpc/platforms/cell/spu_callbacks.c | 6 +++--- >> 5 files changed, 14 insertions(+), 10 deletions(-) >>=20 >> diff --git a/arch/powerpc/include/asm/syscall.h = b/arch/powerpc/include/asm/syscall.h >> index 25fc8ad9a27a..d2a8dfd5de33 100644 >> --- a/arch/powerpc/include/asm/syscall.h >> +++ b/arch/powerpc/include/asm/syscall.h >> @@ -14,9 +14,12 @@ >> #include >> #include >>=20 >> +typedef long (*syscall_fn)(unsigned long, unsigned long, unsigned = long, >> + unsigned long, unsigned long, unsigned long); >> + >> /* ftrace syscalls requires exporting the sys_call_table */ >> -extern const unsigned long sys_call_table[]; >> -extern const unsigned long compat_sys_call_table[]; >> +extern const syscall_fn sys_call_table[]; >> +extern const syscall_fn compat_sys_call_table[]; >=20 > Ah you constify it in this patch. I think the previous patch should = have > kept the const, and it should keep the unsigned long type rather than > use void *. Either that or do this patch first. >=20 >> static inline int syscall_get_nr(struct task_struct *task, struct = pt_regs *regs) >> { >> diff --git a/arch/powerpc/include/asm/syscalls.h = b/arch/powerpc/include/asm/syscalls.h >> index 91417dee534e..e979b7593d2b 100644 >> --- a/arch/powerpc/include/asm/syscalls.h >> +++ b/arch/powerpc/include/asm/syscalls.h >> @@ -8,6 +8,7 @@ >> #include >> #include >>=20 >> +#include >> #ifdef CONFIG_PPC64 >> #include >> #endif >=20 > Is this necessary or should be in another patch? Good spot. This belongs in the patch that produces systbl.c. >=20 >> diff --git a/arch/powerpc/kernel/systbl.c = b/arch/powerpc/kernel/systbl.c >> index 99ffdfef6b9c..b88a9c2a1f50 100644 >> --- a/arch/powerpc/kernel/systbl.c >> +++ b/arch/powerpc/kernel/systbl.c >> @@ -21,10 +21,10 @@ >> #define __SYSCALL(nr, entry) [nr] =3D __powerpc_##entry, >> #define __powerpc_sys_ni_syscall sys_ni_syscall >> #else >> -#define __SYSCALL(nr, entry) [nr] =3D entry, >> +#define __SYSCALL(nr, entry) [nr] =3D (void *) entry, >> #endif >=20 > Also perhaps this should have been in the prior pach and this pach > should change the cast from void to syscall_fn ? This cast to (void *) kicks in when casting functions with six or fewer parameters to six-parameter type accepting and returning u64. Sadly I = can=E2=80=99t find a way to avoid -Wcast-function-type even with (__force syscall_fn) = short of an ugly casti to void* here. Any suggestions? >=20 >>=20 >> -void *sys_call_table[] =3D { >> +const syscall_fn sys_call_table[] =3D { >> #ifdef CONFIG_PPC64 >> #include >> #else >> @@ -35,7 +35,7 @@ void *sys_call_table[] =3D { >> #ifdef CONFIG_COMPAT >> #undef __SYSCALL_WITH_COMPAT >> #define __SYSCALL_WITH_COMPAT(nr, native, compat) __SYSCALL(nr, = compat) >> -void *compat_sys_call_table[] =3D { >> +const syscall_fn compat_sys_call_table[] =3D { >> #include >> }; >> #endif /* CONFIG_COMPAT */ >> diff --git a/arch/powerpc/kernel/vdso.c b/arch/powerpc/kernel/vdso.c >> index 0da287544054..080c9e7de0c0 100644 >> --- a/arch/powerpc/kernel/vdso.c >> +++ b/arch/powerpc/kernel/vdso.c >> @@ -313,10 +313,10 @@ static void __init vdso_setup_syscall_map(void) >> unsigned int i; >>=20 >> for (i =3D 0; i < NR_syscalls; i++) { >> - if (sys_call_table[i] !=3D (unsigned = long)&sys_ni_syscall) >> + if (sys_call_table[i] !=3D (void *)&sys_ni_syscall) >> vdso_data->syscall_map[i >> 5] |=3D 0x80000000UL = >> (i & 0x1f); >> if (IS_ENABLED(CONFIG_COMPAT) && >> - compat_sys_call_table[i] !=3D (unsigned = long)&sys_ni_syscall) >> + compat_sys_call_table[i] !=3D (void = *)&sys_ni_syscall) >=20 > Also these. >=20 > Thanks, > Nick >=20 >> vdso_data->compat_syscall_map[i >> 5] |=3D = 0x80000000UL >> (i & 0x1f); >> } >> } >> diff --git a/arch/powerpc/platforms/cell/spu_callbacks.c = b/arch/powerpc/platforms/cell/spu_callbacks.c >> index fe0d8797a00a..e780c14c5733 100644 >> --- a/arch/powerpc/platforms/cell/spu_callbacks.c >> +++ b/arch/powerpc/platforms/cell/spu_callbacks.c >> @@ -34,15 +34,15 @@ >> * mbind, mq_open, ipc, ... >> */ >>=20 >> -static void *spu_syscall_table[] =3D { >> +static const syscall_fn spu_syscall_table[] =3D { >> #define __SYSCALL_WITH_COMPAT(nr, entry, compat) __SYSCALL(nr, entry) >> -#define __SYSCALL(nr, entry) [nr] =3D entry, >> +#define __SYSCALL(nr, entry) [nr] =3D (void *) entry, >> #include >> }; >>=20 >> long spu_sys_callback(struct spu_syscall_block *s) >> { >> - long (*syscall)(u64 a1, u64 a2, u64 a3, u64 a4, u64 a5, u64 a6); >> + syscall_fn syscall; >>=20 >> if (s->nr_ret >=3D ARRAY_SIZE(spu_syscall_table)) { >> pr_debug("%s: invalid syscall #%lld", __func__, = s->nr_ret); >> --=20 >> 2.34.1