summaryrefslogtreecommitdiff
path: root/arch/arm
diff options
context:
space:
mode:
authorStephen Boyd <sboyd@codeaurora.org>2013-01-14 19:50:42 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-02-03 18:24:40 -0600
commit112ae50d212e65816b9de8ea0010a430569d2fc6 (patch)
treeff837afc66476a7b3c0607179f445facbe9ba9d5 /arch/arm
parent399f41521ecb4dfb55bf86210864ce7c60157d8a (diff)
ARM: 7627/1: Predicate preempt logic on PREEMP_COUNT not PREEMPT alone
commit 568dca15aa2a0f4ddee255894ec393a159f13147 upstream. Patrik Kluba reports that the preempt count becomes invalid due to the preempt_enable() call being unbalanced with a preempt_disable() call in the vfp assembly routines. This happens because preempt_enable() and preempt_disable() update preempt counts under PREEMPT_COUNT=y but the vfp assembly routines do so under PREEMPT=y. In a configuration where PREEMPT=n and DEBUG_ATOMIC_SLEEP=y, PREEMPT_COUNT=y and so the preempt_enable() call in VFP_bounce() keeps subtracting from the preempt count until it goes negative. Fix this by always using PREEMPT_COUNT to decided when to update preempt counts in the ARM assembly code. Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> Reported-by: Patrik Kluba <pkluba@dension.com> Tested-by: Patrik Kluba <pkluba@dension.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/arm')
-rw-r--r--arch/arm/vfp/entry.S6
-rw-r--r--arch/arm/vfp/vfphw.S4
2 files changed, 5 insertions, 5 deletions
diff --git a/arch/arm/vfp/entry.S b/arch/arm/vfp/entry.S
index cc926c985981..323ce1a62bbf 100644
--- a/arch/arm/vfp/entry.S
+++ b/arch/arm/vfp/entry.S
@@ -22,7 +22,7 @@
@ IRQs disabled.
@
ENTRY(do_vfp)
-#ifdef CONFIG_PREEMPT
+#ifdef CONFIG_PREEMPT_COUNT
ldr r4, [r10, #TI_PREEMPT] @ get preempt count
add r11, r4, #1 @ increment it
str r11, [r10, #TI_PREEMPT]
@@ -35,7 +35,7 @@ ENTRY(do_vfp)
ENDPROC(do_vfp)
ENTRY(vfp_null_entry)
-#ifdef CONFIG_PREEMPT
+#ifdef CONFIG_PREEMPT_COUNT
get_thread_info r10
ldr r4, [r10, #TI_PREEMPT] @ get preempt count
sub r11, r4, #1 @ decrement it
@@ -53,7 +53,7 @@ ENDPROC(vfp_null_entry)
__INIT
ENTRY(vfp_testing_entry)
-#ifdef CONFIG_PREEMPT
+#ifdef CONFIG_PREEMPT_COUNT
get_thread_info r10
ldr r4, [r10, #TI_PREEMPT] @ get preempt count
sub r11, r4, #1 @ decrement it
diff --git a/arch/arm/vfp/vfphw.S b/arch/arm/vfp/vfphw.S
index 3a0efaad6090..6ff903e50199 100644
--- a/arch/arm/vfp/vfphw.S
+++ b/arch/arm/vfp/vfphw.S
@@ -167,7 +167,7 @@ vfp_hw_state_valid:
@ else it's one 32-bit instruction, so
@ always subtract 4 from the following
@ instruction address.
-#ifdef CONFIG_PREEMPT
+#ifdef CONFIG_PREEMPT_COUNT
get_thread_info r10
ldr r4, [r10, #TI_PREEMPT] @ get preempt count
sub r11, r4, #1 @ decrement it
@@ -191,7 +191,7 @@ look_for_VFP_exceptions:
@ not recognised by VFP
DBGSTR "not VFP"
-#ifdef CONFIG_PREEMPT
+#ifdef CONFIG_PREEMPT_COUNT
get_thread_info r10
ldr r4, [r10, #TI_PREEMPT] @ get preempt count
sub r11, r4, #1 @ decrement it