Commit 02fe2845 authored by Russell King's avatar Russell King
Browse files

ARM: entry: avoid enabling interrupts in prefetch/data abort handlers



Avoid enabling interrupts if the parent context had interrupts enabled
in the abort handler assembly code, and move this into the breakpoint/
page/alignment fault handlers instead.

This gets rid of some special-casing for the breakpoint fault handlers
from the low level abort handler path.
Acked-by: default avatarWill Deacon <will.deacon@arm.com>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent 8b418616
......@@ -185,20 +185,15 @@ ENDPROC(__und_invalid)
__dabt_svc:
svc_entry
@
@ get ready to re-enable interrupts if appropriate
@
mrs r9, cpsr
tst r5, #PSR_I_BIT
biceq r9, r9, #PSR_I_BIT
#ifdef CONFIG_TRACE_IRQFLAGS
bl trace_hardirqs_off
#endif
dabt_helper
@
@ set desired IRQ state, then call main handler
@ call main handler
@
debug_entry r1
msr cpsr_c, r9
mov r2, sp
bl do_DataAbort
......@@ -211,6 +206,12 @@ __dabt_svc:
@ restore SPSR and restart the instruction
@
ldr r5, [sp, #S_PSR]
#ifdef CONFIG_TRACE_IRQFLAGS
tst r5, #PSR_I_BIT
bleq trace_hardirqs_on
tst r5, #PSR_I_BIT
blne trace_hardirqs_off
#endif
svc_exit r5 @ return from exception
UNWIND(.fnend )
ENDPROC(__dabt_svc)
......@@ -307,16 +308,11 @@ ENDPROC(__und_svc)
__pabt_svc:
svc_entry
@
@ re-enable interrupts if appropriate
@
mrs r9, cpsr
tst r5, #PSR_I_BIT
biceq r9, r9, #PSR_I_BIT
#ifdef CONFIG_TRACE_IRQFLAGS
bl trace_hardirqs_off
#endif
pabt_helper
debug_entry r1
msr cpsr_c, r9 @ Maybe enable interrupts
mov r2, sp @ regs
bl do_PrefetchAbort @ call abort handler
......@@ -329,6 +325,12 @@ __pabt_svc:
@ restore SPSR and restart the instruction
@
ldr r5, [sp, #S_PSR]
#ifdef CONFIG_TRACE_IRQFLAGS
tst r5, #PSR_I_BIT
bleq trace_hardirqs_on
tst r5, #PSR_I_BIT
blne trace_hardirqs_off
#endif
svc_exit r5 @ return from exception
UNWIND(.fnend )
ENDPROC(__pabt_svc)
......@@ -412,11 +414,6 @@ __dabt_usr:
kuser_cmpxchg_check
dabt_helper
@
@ IRQs on, then call the main handler
@
debug_entry r1
enable_irq
mov r2, sp
adr lr, BSYM(ret_from_exception)
b do_DataAbort
......@@ -663,8 +660,6 @@ ENDPROC(__und_usr_unknown)
__pabt_usr:
usr_entry
pabt_helper
debug_entry r1
enable_irq @ Enable interrupts
mov r2, sp @ regs
bl do_PrefetchAbort @ call abort handler
UNWIND(.fnend )
......
......@@ -165,25 +165,6 @@
.endm
#endif /* !CONFIG_THUMB2_KERNEL */
@
@ Debug exceptions are taken as prefetch or data aborts.
@ We must disable preemption during the handler so that
@ we can access the debug registers safely.
@
.macro debug_entry, fsr
#if defined(CONFIG_HAVE_HW_BREAKPOINT) && defined(CONFIG_PREEMPT)
ldr r4, =0x40f @ mask out fsr.fs
and r5, r4, \fsr
cmp r5, #2 @ debug exception
bne 1f
get_thread_info r10
ldr r6, [r10, #TI_PREEMPT] @ get preempt count
add r11, r6, #1 @ increment it
str r11, [r10, #TI_PREEMPT]
1:
#endif
.endm
/*
* These are the registers used in the syscall handler, and allow us to
* have in theory up to 7 arguments to a function - r0 to r6.
......
......@@ -796,7 +796,7 @@ static void breakpoint_handler(unsigned long unknown, struct pt_regs *regs)
/*
* Called from either the Data Abort Handler [watchpoint] or the
* Prefetch Abort Handler [breakpoint] with preemption disabled.
* Prefetch Abort Handler [breakpoint] with interrupts disabled.
*/
static int hw_breakpoint_pending(unsigned long addr, unsigned int fsr,
struct pt_regs *regs)
......@@ -804,8 +804,10 @@ static int hw_breakpoint_pending(unsigned long addr, unsigned int fsr,
int ret = 0;
u32 dscr;
/* We must be called with preemption disabled. */
WARN_ON(preemptible());
preempt_disable();
if (interrupts_enabled(regs))
local_irq_enable();
/* We only handle watchpoints and hardware breakpoints. */
ARM_DBG_READ(c1, 0, dscr);
......@@ -824,10 +826,6 @@ static int hw_breakpoint_pending(unsigned long addr, unsigned int fsr,
ret = 1; /* Unhandled fault. */
}
/*
* Re-enable preemption after it was disabled in the
* low-level exception handling code.
*/
preempt_enable();
return ret;
......
......@@ -727,6 +727,9 @@ do_alignment(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
int isize = 4;
int thumb2_32b = 0;
if (interrupts_enabled(regs))
local_irq_enable();
instrptr = instruction_pointer(regs);
fs = get_fs();
......
......@@ -285,6 +285,10 @@ do_page_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
tsk = current;
mm = tsk->mm;
/* Enable interrupts if they were enabled in the parent context. */
if (interrupts_enabled(regs))
local_irq_enable();
/*
* If we're in an interrupt or have no user
* context, we must not take the fault..
......
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