[PATCH v3 5/6] powerpc/64s: Blacklist functions invoked on a trap
Naveen N. Rao
naveen.n.rao at linux.vnet.ibm.com
Thu Jun 22 04:38:41 AEST 2017
Blacklist all functions involved while handling a trap. We:
- convert some of the symbols into private symbols,
- remove the duplicate 'restore' symbol, and
- blacklist most functions involved while handling a trap.
Reviewed-by: Masami Hiramatsu <mhiramat at kernel.org>
Signed-off-by: Naveen N. Rao <naveen.n.rao at linux.vnet.ibm.com>
---
arch/powerpc/kernel/entry_64.S | 47 +++++++++++++++++++++---------------
arch/powerpc/kernel/exceptions-64s.S | 2 ++
arch/powerpc/kernel/traps.c | 3 +++
3 files changed, 32 insertions(+), 20 deletions(-)
diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S
index feeeadc9aa71..d376f07153d7 100644
--- a/arch/powerpc/kernel/entry_64.S
+++ b/arch/powerpc/kernel/entry_64.S
@@ -184,7 +184,7 @@ system_call: /* label this so stack traces look sane */
#ifdef CONFIG_PPC_BOOK3S
/* No MSR:RI on BookE */
andi. r10,r8,MSR_RI
- beq- unrecov_restore
+ beq- .Lunrecov_restore
#endif
/*
* Disable interrupts so current_thread_info()->flags can't change,
@@ -424,6 +424,7 @@ _GLOBAL(save_nvgprs)
clrrdi r0,r11,1
std r0,_TRAP(r1)
blr
+_ASM_NOKPROBE_SYMBOL(save_nvgprs);
/*
@@ -672,18 +673,18 @@ _GLOBAL(ret_from_except_lite)
* Use the internal debug mode bit to do this.
*/
andis. r0,r3,DBCR0_IDM at h
- beq restore
+ beq fast_exc_return_irq
mfmsr r0
rlwinm r0,r0,0,~MSR_DE /* Clear MSR.DE */
mtmsr r0
mtspr SPRN_DBCR0,r3
li r10, -1
mtspr SPRN_DBSR,r10
- b restore
+ b fast_exc_return_irq
#else
addi r3,r1,STACK_FRAME_OVERHEAD
bl restore_math
- b restore
+ b fast_exc_return_irq
#endif
1: andi. r0,r4,_TIF_NEED_RESCHED
beq 2f
@@ -696,7 +697,7 @@ _GLOBAL(ret_from_except_lite)
bne 3f /* only restore TM if nothing else to do */
addi r3,r1,STACK_FRAME_OVERHEAD
bl restore_tm_state
- b restore
+ b fast_exc_return_irq
3:
#endif
bl save_nvgprs
@@ -748,14 +749,14 @@ resume_kernel:
#ifdef CONFIG_PREEMPT
/* Check if we need to preempt */
andi. r0,r4,_TIF_NEED_RESCHED
- beq+ restore
+ beq+ fast_exc_return_irq
/* Check that preempt_count() == 0 and interrupts are enabled */
lwz r8,TI_PREEMPT(r9)
cmpwi cr1,r8,0
ld r0,SOFTE(r1)
cmpdi r0,0
crandc eq,cr1*4+eq,eq
- bne restore
+ bne fast_exc_return_irq
/*
* Here we are preempting the current task. We want to make
@@ -786,7 +787,6 @@ resume_kernel:
.globl fast_exc_return_irq
fast_exc_return_irq:
-restore:
/*
* This is the main kernel exit path. First we check if we
* are about to re-enable interrupts
@@ -794,11 +794,11 @@ restore:
ld r5,SOFTE(r1)
lbz r6,PACASOFTIRQEN(r13)
cmpwi cr0,r5,0
- beq restore_irq_off
+ beq .Lrestore_irq_off
/* We are enabling, were we already enabled ? Yes, just return */
cmpwi cr0,r6,1
- beq cr0,do_restore
+ beq cr0,.Ldo_restore
/*
* We are about to soft-enable interrupts (we are hard disabled
@@ -807,14 +807,14 @@ restore:
*/
lbz r0,PACAIRQHAPPENED(r13)
cmpwi cr0,r0,0
- bne- restore_check_irq_replay
+ bne- .Lrestore_check_irq_replay
/*
* Get here when nothing happened while soft-disabled, just
* soft-enable and move-on. We will hard-enable as a side
* effect of rfi
*/
-restore_no_replay:
+.Lrestore_no_replay:
TRACE_ENABLE_INTS
li r0,1
stb r0,PACASOFTIRQEN(r13);
@@ -822,7 +822,7 @@ restore_no_replay:
/*
* Final return path. BookE is handled in a different file
*/
-do_restore:
+.Ldo_restore:
#ifdef CONFIG_PPC_BOOK3E
b exception_return_book3e
#else
@@ -856,7 +856,7 @@ fast_exception_return:
REST_8GPRS(5, r1)
andi. r0,r3,MSR_RI
- beq- unrecov_restore
+ beq- .Lunrecov_restore
/* Load PPR from thread struct before we clear MSR:RI */
BEGIN_FTR_SECTION
@@ -914,7 +914,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR)
* make sure that in this case, we also clear PACA_IRQ_HARD_DIS
* or that bit can get out of sync and bad things will happen
*/
-restore_irq_off:
+.Lrestore_irq_off:
ld r3,_MSR(r1)
lbz r7,PACAIRQHAPPENED(r13)
andi. r0,r3,MSR_EE
@@ -924,13 +924,13 @@ restore_irq_off:
1: li r0,0
stb r0,PACASOFTIRQEN(r13);
TRACE_DISABLE_INTS
- b do_restore
+ b .Ldo_restore
/*
* Something did happen, check if a re-emit is needed
* (this also clears paca->irq_happened)
*/
-restore_check_irq_replay:
+.Lrestore_check_irq_replay:
/* XXX: We could implement a fast path here where we check
* for irq_happened being just 0x01, in which case we can
* clear it and return. That means that we would potentially
@@ -940,7 +940,7 @@ restore_check_irq_replay:
*/
bl __check_irq_replay
cmpwi cr0,r3,0
- beq restore_no_replay
+ beq .Lrestore_no_replay
/*
* We need to re-emit an interrupt. We do so by re-using our
@@ -989,10 +989,17 @@ restore_check_irq_replay:
#endif /* CONFIG_PPC_DOORBELL */
1: b ret_from_except /* What else to do here ? */
-unrecov_restore:
+.Lunrecov_restore:
addi r3,r1,STACK_FRAME_OVERHEAD
bl unrecoverable_exception
- b unrecov_restore
+ b .Lunrecov_restore
+
+_ASM_NOKPROBE_SYMBOL(ret_from_except);
+_ASM_NOKPROBE_SYMBOL(ret_from_except_lite);
+_ASM_NOKPROBE_SYMBOL(resume_kernel);
+_ASM_NOKPROBE_SYMBOL(fast_exc_return_irq);
+_ASM_NOKPROBE_SYMBOL(fast_exception_return);
+
#ifdef CONFIG_PPC_RTAS
/*
diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
index 2df6d7b3070f..0d025dfb52d8 100644
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S
@@ -1589,6 +1589,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_CFAR)
1: addi r3,r1,STACK_FRAME_OVERHEAD
bl kernel_bad_stack
b 1b
+_ASM_NOKPROBE_SYMBOL(bad_stack);
/*
* When doorbell is triggered from system reset wakeup, the message is
@@ -1650,3 +1651,4 @@ ALT_FTR_SECTION_END_IFSET(CPU_FTR_HVMODE)
1:
blr
+_ASM_NOKPROBE_SYMBOL(__replay_interrupt)
diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
index d4e545d27ef9..bfcfd9ef09f2 100644
--- a/arch/powerpc/kernel/traps.c
+++ b/arch/powerpc/kernel/traps.c
@@ -237,6 +237,7 @@ void die(const char *str, struct pt_regs *regs, long err)
err = 0;
oops_end(flags, regs, err);
}
+NOKPROBE_SYMBOL(die);
void user_single_step_siginfo(struct task_struct *tsk,
struct pt_regs *regs, siginfo_t *info)
@@ -1968,6 +1969,7 @@ void unrecoverable_exception(struct pt_regs *regs)
regs->trap, regs->nip);
die("Unrecoverable exception", regs, SIGABRT);
}
+NOKPROBE_SYMBOL(unrecoverable_exception);
#if defined(CONFIG_BOOKE_WDT) || defined(CONFIG_40x)
/*
@@ -1998,6 +2000,7 @@ void kernel_bad_stack(struct pt_regs *regs)
regs->gpr[1], regs->nip);
die("Bad kernel stack pointer", regs, SIGABRT);
}
+NOKPROBE_SYMBOL(kernel_bad_stack);
void __init trap_init(void)
{
--
2.13.1
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