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a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1702302521; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=mptyI+2MUmEUOVgsCKUKUDyQ+zkn0mcu28+VmTFAif0=; b=Uf4SIDrL22ohW4Mkmsi4Ikkh3CzK5tb4BCBkjt1devyV/GC9K/gWaJiBQPRzyiqOIn5pDI tl3dckYrZRG2pe+4zQggVq0ehIgKqXSildsiEqFetSqDQgl79rKfpN0YmoZqfFpiLLKZyt 9xw0xfTxARtzV0ufGg0VGc7q6RnAUFk= From: Juergen Gross To: minios-devel@lists.xenproject.org, xen-devel@lists.xenproject.org Cc: samuel.thibault@ens-lyon.org, wl@xen.org, Juergen Gross Subject: [PATCH 2/3] Mini-OS: drop in_callback variable Date: Mon, 11 Dec 2023 14:48:26 +0100 Message-Id: <20231211134827.7130-3-jgross@suse.com> X-Mailer: git-send-email 2.35.3 In-Reply-To: <20231211134827.7130-1-jgross@suse.com> References: <20231211134827.7130-1-jgross@suse.com> MIME-Version: 1.0 X-Spamd-Bar: / Authentication-Results: smtp-out1.suse.de; dkim=pass header.d=suse.com header.s=susede1 header.b=Uf4SIDrL; 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FUZZY_BLOCKED(0.00)[rspamd.com]; RCVD_TLS_ALL(0.00)[] X-Rspamd-Queue-Id: 15DB3223E4 Now that do_hypervisor_callback() is always called with interrupts off the in_callback variable meant to handle recursive calls of do_hypervisor_callback() can be dropped. As a precaution add a test to do_hypervisor_callback() that interrupts are really disabled and crash in case this is not true. Signed-off-by: Juergen Gross Reviewed-by: Samuel Thibault --- hypervisor.c | 6 ------ include/hypervisor.h | 2 -- sched.c | 11 ----------- 3 files changed, 19 deletions(-) diff --git a/hypervisor.c b/hypervisor.c index 5309daa3..6facce3e 100644 --- a/hypervisor.c +++ b/hypervisor.c @@ -37,8 +37,6 @@ EXPORT_SYMBOL(hypercall_page); ((sh)->evtchn_pending[idx] & \ ~(sh)->evtchn_mask[idx]) -int in_callback; - #ifndef CONFIG_PARAVIRT extern shared_info_t shared_info; @@ -104,8 +102,6 @@ void do_hypervisor_callback(struct pt_regs *regs) BUG_ON(!irqs_disabled()); - in_callback = 1; - vcpu_info->evtchn_upcall_pending = 0; /* NB x86. No need for a barrier here -- XCHG is a barrier on x86. */ #if !defined(__i386__) && !defined(__x86_64__) @@ -127,8 +123,6 @@ void do_hypervisor_callback(struct pt_regs *regs) do_event(port, regs); } } - - in_callback = 0; } void force_evtchn_callback(void) diff --git a/include/hypervisor.h b/include/hypervisor.h index 1d092719..b852a42a 100644 --- a/include/hypervisor.h +++ b/include/hypervisor.h @@ -50,6 +50,4 @@ void mask_evtchn(uint32_t port); void unmask_evtchn(uint32_t port); void clear_evtchn(uint32_t port); -extern int in_callback; - #endif /* __HYPERVISOR_H__ */ diff --git a/sched.c b/sched.c index e162cb60..3335efa0 100644 --- a/sched.c +++ b/sched.c @@ -76,11 +76,6 @@ void schedule(void) prev = current; local_irq_save(flags); - if (in_callback) { - printk("Must not call schedule() from a callback\n"); - BUG(); - } - do { /* Examine all threads. Find a runnable thread, but also wake up expired ones and find the @@ -151,15 +146,12 @@ struct thread* create_thread(char *name, void (*function)(void *), void *data) EXPORT_SYMBOL(create_thread); #ifdef HAVE_LIBC -static struct _reent callback_reent; struct _reent *__getreent(void) { struct _reent *_reent; if (!threads_started) _reent = _impure_ptr; - else if (in_callback) - _reent = &callback_reent; else _reent = &get_current()->reent; @@ -246,9 +238,6 @@ void init_sched(void) { printk("Initialising scheduler\n"); -#ifdef HAVE_LIBC - _REENT_INIT_PTR((&callback_reent)) -#endif idle_thread = create_thread("Idle", idle_thread_fn, NULL); }