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Fri, 30 Oct 2020 01:18:09 +0000 (GMT) From: Nathan Lynch To: linuxppc-dev@lists.ozlabs.org Subject: [PATCH 04/29] powerpc/rtas: rtas_ibm_suspend_me -> rtas_ibm_suspend_me_unsafe Date: Thu, 29 Oct 2020 20:17:40 -0500 Message-Id: <20201030011805.1224603-5-nathanl@linux.ibm.com> X-Mailer: git-send-email 2.25.4 In-Reply-To: <20201030011805.1224603-1-nathanl@linux.ibm.com> References: <20201030011805.1224603-1-nathanl@linux.ibm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.312, 18.0.737 definitions=2020-10-29_12:2020-10-29, 2020-10-29 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 phishscore=0 mlxlogscore=747 priorityscore=1501 suspectscore=3 bulkscore=0 adultscore=0 mlxscore=0 spamscore=0 lowpriorityscore=0 clxscore=1015 malwarescore=0 impostorscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2010300001 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: tyreld@linux.ibm.com, ajd@linux.ibm.com, mmc@linux.vnet.ibm.com, cforno12@linux.vnet.ibm.com, drt@linux.vnet.ibm.com, brking@linux.ibm.com Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" The pseries partition suspend sequence requires that all active CPUs call H_JOIN, which suspends all but one of them with interrupts disabled. The "chosen" CPU is then to call ibm,suspend-me to complete the suspend. Upon returning from ibm,suspend-me, the chosen CPU is to use H_PROD to wake the joined CPUs. Using on_each_cpu() for this, as rtas_ibm_suspend_me() does to implement partition migration, is susceptible to deadlock with other users of on_each_cpu() and with users of stop_machine APIs. The callback passed to on_each_cpu() is not allowed to synchronize with other CPUs in the way it is used here. Complicating the fix is the fact that rtas_ibm_suspend_me() also occupies the function name that should be used to provide a more conventional wrapper for ibm,suspend-me. Rename rtas_ibm_suspend_me() to rtas_ibm_suspend_me_unsafe() to free up the name and indicate that it should not gain users. Signed-off-by: Nathan Lynch --- arch/powerpc/include/asm/rtas.h | 2 +- arch/powerpc/kernel/rtas.c | 6 +++--- arch/powerpc/platforms/pseries/mobility.c | 2 +- 3 files changed, 5 insertions(+), 5 deletions(-) diff --git a/arch/powerpc/include/asm/rtas.h b/arch/powerpc/include/asm/rtas.h index f060181a0d32..8436ed01567b 100644 --- a/arch/powerpc/include/asm/rtas.h +++ b/arch/powerpc/include/asm/rtas.h @@ -257,7 +257,7 @@ extern int rtas_set_indicator_fast(int indicator, int index, int new_value); extern void rtas_progress(char *s, unsigned short hex); extern int rtas_suspend_cpu(struct rtas_suspend_me_data *data); extern int rtas_suspend_last_cpu(struct rtas_suspend_me_data *data); -extern int rtas_ibm_suspend_me(u64 handle); +int rtas_ibm_suspend_me_unsafe(u64 handle); struct rtc_time; extern time64_t rtas_get_boot_time(void); diff --git a/arch/powerpc/kernel/rtas.c b/arch/powerpc/kernel/rtas.c index 132b2ae39009..33adefa84a42 100644 --- a/arch/powerpc/kernel/rtas.c +++ b/arch/powerpc/kernel/rtas.c @@ -843,7 +843,7 @@ static void rtas_percpu_suspend_me(void *info) __rtas_suspend_cpu((struct rtas_suspend_me_data *)info, 1); } -int rtas_ibm_suspend_me(u64 handle) +int rtas_ibm_suspend_me_unsafe(u64 handle) { long state; long rc; @@ -898,7 +898,7 @@ int rtas_ibm_suspend_me(u64 handle) return atomic_read(&data.error); } #else /* CONFIG_PPC_PSERIES */ -int rtas_ibm_suspend_me(u64 handle) +int rtas_ibm_suspend_me_unsafe(u64 handle) { return -ENOSYS; } @@ -1184,7 +1184,7 @@ SYSCALL_DEFINE1(rtas, struct rtas_args __user *, uargs) int rc = 0; u64 handle = ((u64)be32_to_cpu(args.args[0]) << 32) | be32_to_cpu(args.args[1]); - rc = rtas_ibm_suspend_me(handle); + rc = rtas_ibm_suspend_me_unsafe(handle); if (rc == -EAGAIN) args.rets[0] = cpu_to_be32(RTAS_NOT_SUSPENDABLE); else if (rc == -EIO) diff --git a/arch/powerpc/platforms/pseries/mobility.c b/arch/powerpc/platforms/pseries/mobility.c index d6f4162478a5..b6de65cbfcd9 100644 --- a/arch/powerpc/platforms/pseries/mobility.c +++ b/arch/powerpc/platforms/pseries/mobility.c @@ -370,7 +370,7 @@ static ssize_t migration_store(struct class *class, return rc; do { - rc = rtas_ibm_suspend_me(streamid); + rc = rtas_ibm_suspend_me_unsafe(streamid); if (rc == -EAGAIN) ssleep(1); } while (rc == -EAGAIN); -- 2.25.4