[PATCH v4 05/12] xen/spinlock: add rspin_[un]lock_irq[save|restore]()

From: Juergen Gross <jgross@suse.com>
To: xen-devel@lists.xenproject.org
Cc: "Juergen Gross" <jgross@suse.com>,
	"Jan Beulich" <jbeulich@suse.com>,
	"Andrew Cooper" <andrew.cooper3@citrix.com>,
	"Roger Pau Monné" <roger.pau@citrix.com>, "Wei Liu" <wl@xen.org>,
	"George Dunlap" <george.dunlap@citrix.com>,
	"Julien Grall" <julien@xen.org>,
	"Stefano Stabellini" <sstabellini@kernel.org>
Subject: [PATCH v4 05/12] xen/spinlock: add rspin_[un]lock_irq[save|restore]()
Date: Tue, 12 Dec 2023 10:47:18 +0100	[thread overview]
Message-ID: <20231212094725.22184-6-jgross@suse.com> (raw)
In-Reply-To: <20231212094725.22184-1-jgross@suse.com>

Instead of special casing rspin_lock_irqsave() and
rspin_unlock_irqrestore() for the console lock, add those functions
to spinlock handling and use them where needed.

Signed-off-by: Juergen Gross <jgross@suse.com>
---
V2:
- new patch
---
 xen/arch/x86/traps.c       | 14 ++++++++------
 xen/common/spinlock.c      | 16 ++++++++++++++++
 xen/drivers/char/console.c | 18 +-----------------
 xen/include/xen/console.h  |  5 +++--
 xen/include/xen/spinlock.h |  7 +++++++
 5 files changed, 35 insertions(+), 25 deletions(-)

diff --git a/xen/arch/x86/traps.c b/xen/arch/x86/traps.c
index 7724306116..21227877b3 100644
--- a/xen/arch/x86/traps.c
+++ b/xen/arch/x86/traps.c
@@ -647,13 +647,15 @@ void show_stack_overflow(unsigned int cpu, const struct cpu_user_regs *regs)
 void show_execution_state(const struct cpu_user_regs *regs)
 {
     /* Prevent interleaving of output. */
-    unsigned long flags = console_lock_recursive_irqsave();
+    unsigned long flags;
+
+    rspin_lock_irqsave(&console_lock, flags);
 
     show_registers(regs);
     show_code(regs);
     show_stack(regs);
 
-    console_unlock_recursive_irqrestore(flags);
+    rspin_unlock_irqrestore(&console_lock, flags);
 }
 
 void cf_check show_execution_state_nonconst(struct cpu_user_regs *regs)
@@ -663,7 +665,7 @@ void cf_check show_execution_state_nonconst(struct cpu_user_regs *regs)
 
 void vcpu_show_execution_state(struct vcpu *v)
 {
-    unsigned long flags = 0;
+    unsigned long flags;
 
     if ( test_bit(_VPF_down, &v->pause_flags) )
     {
@@ -698,7 +700,7 @@ void vcpu_show_execution_state(struct vcpu *v)
 #endif
 
     /* Prevent interleaving of output. */
-    flags = console_lock_recursive_irqsave();
+    rspin_lock_irqsave(&console_lock, flags);
 
     vcpu_show_registers(v);
 
@@ -708,7 +710,7 @@ void vcpu_show_execution_state(struct vcpu *v)
          * Stop interleaving prevention: The necessary P2M lookups involve
          * locking, which has to occur with IRQs enabled.
          */
-        console_unlock_recursive_irqrestore(flags);
+        rspin_unlock_irqrestore(&console_lock, flags);
 
         show_hvm_stack(v, &v->arch.user_regs);
     }
@@ -717,7 +719,7 @@ void vcpu_show_execution_state(struct vcpu *v)
         if ( guest_kernel_mode(v, &v->arch.user_regs) )
             show_guest_stack(v, &v->arch.user_regs);
 
-        console_unlock_recursive_irqrestore(flags);
+        rspin_unlock_irqrestore(&console_lock, flags);
     }
 
 #ifdef CONFIG_HVM
diff --git a/xen/common/spinlock.c b/xen/common/spinlock.c
index 422a7fb1db..c1a9ba1304 100644
--- a/xen/common/spinlock.c
+++ b/xen/common/spinlock.c
@@ -475,6 +475,16 @@ void rspin_lock(rspinlock_t *lock)
     lock->recurse_cnt++;
 }
 
+unsigned long __rspin_lock_irqsave(rspinlock_t *lock)
+{
+    unsigned long flags;
+
+    local_irq_save(flags);
+    rspin_lock(lock);
+
+    return flags;
+}
+
 void rspin_unlock(rspinlock_t *lock)
 {
     if ( likely(--lock->recurse_cnt == 0) )
@@ -484,6 +494,12 @@ void rspin_unlock(rspinlock_t *lock)
     }
 }
 
+void rspin_unlock_irqrestore(rspinlock_t *lock, unsigned long flags)
+{
+    rspin_unlock(lock);
+    local_irq_restore(flags);
+}
+
 #ifdef CONFIG_DEBUG_LOCK_PROFILE
 
 struct lock_profile_anc {
diff --git a/xen/drivers/char/console.c b/xen/drivers/char/console.c
index f6f61dc5a1..1db2bbdb6a 100644
--- a/xen/drivers/char/console.c
+++ b/xen/drivers/char/console.c
@@ -120,7 +120,7 @@ static int __read_mostly sercon_handle = -1;
 int8_t __read_mostly opt_console_xen; /* console=xen */
 #endif
 
-static DEFINE_RSPINLOCK(console_lock);
+DEFINE_RSPINLOCK(console_lock);
 
 /*
  * To control the amount of printing, thresholds are added.
@@ -1158,22 +1158,6 @@ void console_end_log_everything(void)
     atomic_dec(&print_everything);
 }
 
-unsigned long console_lock_recursive_irqsave(void)
-{
-    unsigned long flags;
-
-    local_irq_save(flags);
-    rspin_lock(&console_lock);
-
-    return flags;
-}
-
-void console_unlock_recursive_irqrestore(unsigned long flags)
-{
-    rspin_unlock(&console_lock);
-    local_irq_restore(flags);
-}
-
 void console_force_unlock(void)
 {
     watchdog_disable();
diff --git a/xen/include/xen/console.h b/xen/include/xen/console.h
index 68759862e8..583c38f064 100644
--- a/xen/include/xen/console.h
+++ b/xen/include/xen/console.h
@@ -8,8 +8,11 @@
 #define __CONSOLE_H__
 
 #include <xen/inttypes.h>
+#include <xen/spinlock.h>
 #include <public/xen.h>
 
+extern rspinlock_t console_lock;
+
 struct xen_sysctl_readconsole;
 long read_console_ring(struct xen_sysctl_readconsole *op);
 
@@ -20,8 +23,6 @@ void console_init_postirq(void);
 void console_endboot(void);
 int console_has(const char *device);
 
-unsigned long console_lock_recursive_irqsave(void);
-void console_unlock_recursive_irqrestore(unsigned long flags);
 void console_force_unlock(void);
 
 void console_start_sync(void);
diff --git a/xen/include/xen/spinlock.h b/xen/include/xen/spinlock.h
index ee536c302c..05b97c1e03 100644
--- a/xen/include/xen/spinlock.h
+++ b/xen/include/xen/spinlock.h
@@ -218,7 +218,14 @@ void _spin_barrier(spinlock_t *lock);
  */
 int rspin_trylock(rspinlock_t *lock);
 void rspin_lock(rspinlock_t *lock);
+#define rspin_lock_irqsave(l, f)                                \
+    ({                                                          \
+        BUILD_BUG_ON(sizeof(f) != sizeof(unsigned long));       \
+        ((f) = __rspin_lock_irqsave(l));                        \
+    })
+unsigned long __rspin_lock_irqsave(rspinlock_t *lock);
 void rspin_unlock(rspinlock_t *lock);
+void rspin_unlock_irqrestore(rspinlock_t *lock, unsigned long flags);
 
 #define spin_lock(l)                  _spin_lock(l)
 #define spin_lock_cb(l, c, d)         _spin_lock_cb(l, c, d)
-- 
2.35.3


