From: Helge Deller <deller@gmx.de>
To: Sam James <sam@gentoo.org>, linux-parisc@vger.kernel.org
Subject: [PATCH] Fix CONFIG_TLB_PTLOCK to work with lightweight spinlock checks
Date: Sun, 13 Aug 2023 11:49:03 +0200 [thread overview]
Message-ID: <ZNinD9QbRUn6BSiR@p100> (raw)
For the TLB_PTLOCK checks we used an optimization to store the spc
register into the spinlock to unlock it. This optimization works as
long as the lightweight spinlock checks (CONFIG_LIGHTWEIGHT_SPINLOCK_CHECK)
aren't enabled, because they really check if the lock word is zero or
__ARCH_SPIN_LOCK_UNLOCKED_VAL and abort with a kernel crash
("Spinlock was trashed") otherwise.
Drop that optimization to make it possible to activate both checks
at the same time.
Noticed-by: Sam James <sam@gentoo.org>
Signed-off-by: Helge Deller <deller@gmx.de>
Cc: stable@vger.kernel.org # v6.4+
Fixes: 15e64ef6520e ("parisc: Add lightweight spinlock checks")
diff --git a/arch/parisc/kernel/entry.S b/arch/parisc/kernel/entry.S
index 0e5ebfe8d9d2..bddf9c905c01 100644
--- a/arch/parisc/kernel/entry.S
+++ b/arch/parisc/kernel/entry.S
@@ -25,6 +25,7 @@
#include <asm/traps.h>
#include <asm/thread_info.h>
#include <asm/alternative.h>
+#include <asm/spinlock_types.h>
#include <linux/linkage.h>
#include <linux/pgtable.h>
@@ -415,24 +416,22 @@
.endm
/* Release page_table_lock without reloading lock address.
- Note that the values in the register spc are limited to
- NR_SPACE_IDS (262144). Thus, the stw instruction always
- stores a nonzero value even when register spc is 64 bits.
We use an ordered store to ensure all prior accesses are
performed prior to releasing the lock. */
- .macro ptl_unlock0 spc,tmp
+ .macro ptl_unlock0 spc,tmp,tmp2
#ifdef CONFIG_TLB_PTLOCK
-98: or,COND(=) %r0,\spc,%r0
- stw,ma \spc,0(\tmp)
+98: ldi __ARCH_SPIN_LOCK_UNLOCKED_VAL, \tmp2
+ or,COND(=) %r0,\spc,%r0
+ stw,ma \tmp2,0(\tmp)
99: ALTERNATIVE(98b, 99b, ALT_COND_NO_SMP, INSN_NOP)
#endif
.endm
/* Release page_table_lock. */
- .macro ptl_unlock1 spc,tmp
+ .macro ptl_unlock1 spc,tmp,tmp2
#ifdef CONFIG_TLB_PTLOCK
98: get_ptl \tmp
- ptl_unlock0 \spc,\tmp
+ ptl_unlock0 \spc,\tmp,\tmp2
99: ALTERNATIVE(98b, 99b, ALT_COND_NO_SMP, INSN_NOP)
#endif
.endm
@@ -1125,7 +1124,7 @@ dtlb_miss_20w:
idtlbt pte,prot
- ptl_unlock1 spc,t0
+ ptl_unlock1 spc,t0,t1
rfir
nop
@@ -1151,7 +1150,7 @@ nadtlb_miss_20w:
idtlbt pte,prot
- ptl_unlock1 spc,t0
+ ptl_unlock1 spc,t0,t1
rfir
nop
@@ -1185,7 +1184,7 @@ dtlb_miss_11:
mtsp t1, %sr1 /* Restore sr1 */
- ptl_unlock1 spc,t0
+ ptl_unlock1 spc,t0,t1
rfir
nop
@@ -1218,7 +1217,7 @@ nadtlb_miss_11:
mtsp t1, %sr1 /* Restore sr1 */
- ptl_unlock1 spc,t0
+ ptl_unlock1 spc,t0,t1
rfir
nop
@@ -1247,7 +1246,7 @@ dtlb_miss_20:
idtlbt pte,prot
- ptl_unlock1 spc,t0
+ ptl_unlock1 spc,t0,t1
rfir
nop
@@ -1275,7 +1274,7 @@ nadtlb_miss_20:
idtlbt pte,prot
- ptl_unlock1 spc,t0
+ ptl_unlock1 spc,t0,t1
rfir
nop
@@ -1320,7 +1319,7 @@ itlb_miss_20w:
iitlbt pte,prot
- ptl_unlock1 spc,t0
+ ptl_unlock1 spc,t0,t1
rfir
nop
@@ -1344,7 +1343,7 @@ naitlb_miss_20w:
iitlbt pte,prot
- ptl_unlock1 spc,t0
+ ptl_unlock1 spc,t0,t1
rfir
nop
@@ -1378,7 +1377,7 @@ itlb_miss_11:
mtsp t1, %sr1 /* Restore sr1 */
- ptl_unlock1 spc,t0
+ ptl_unlock1 spc,t0,t1
rfir
nop
@@ -1402,7 +1401,7 @@ naitlb_miss_11:
mtsp t1, %sr1 /* Restore sr1 */
- ptl_unlock1 spc,t0
+ ptl_unlock1 spc,t0,t1
rfir
nop
@@ -1432,7 +1431,7 @@ itlb_miss_20:
iitlbt pte,prot
- ptl_unlock1 spc,t0
+ ptl_unlock1 spc,t0,t1
rfir
nop
@@ -1452,7 +1451,7 @@ naitlb_miss_20:
iitlbt pte,prot
- ptl_unlock1 spc,t0
+ ptl_unlock1 spc,t0,t1
rfir
nop
@@ -1482,7 +1481,7 @@ dbit_trap_20w:
idtlbt pte,prot
- ptl_unlock0 spc,t0
+ ptl_unlock0 spc,t0,t1
rfir
nop
#else
@@ -1508,7 +1507,7 @@ dbit_trap_11:
mtsp t1, %sr1 /* Restore sr1 */
- ptl_unlock0 spc,t0
+ ptl_unlock0 spc,t0,t1
rfir
nop
@@ -1528,7 +1527,7 @@ dbit_trap_20:
idtlbt pte,prot
- ptl_unlock0 spc,t0
+ ptl_unlock0 spc,t0,t1
rfir
nop
#endif
reply other threads:[~2023-08-13 9:49 UTC|newest]
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