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powerpc/entry32: Blacklist exception entry points for kprobe.

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kprobe does not handle events happening in real mode.

As exception entry points are running with MMU disabled,
blacklist them.

The handling of TLF_NAPPING and TLF_SLEEPING is moved before the
CONFIG_TRACE_IRQFLAGS which contains 'reenable_mmu' because from there
kprobe will be possible as the kernel will run with MMU enabled.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Acked-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/f61ac599855e674ebb592464d0ea32a3ba9c6644.1585670437.git.christophe.leroy@c-s.fr
This commit is contained in:
Christophe Leroy 2020-03-31 16:03:45 +00:00 committed by Michael Ellerman
parent 5f32e8361c
commit a616c44211
1 changed files with 22 additions and 15 deletions
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37
arch/powerpc/kernel/entry_32.S
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@ -50,6 +50,7 @@ mcheck_transfer_to_handler:
mfspr r0,SPRN_DSRR1
stw r0,_DSRR1(r11)
/* fall through */
_ASM_NOKPROBE_SYMBOL(mcheck_transfer_to_handler)
.globl debug_transfer_to_handler
debug_transfer_to_handler:
@ -58,6 +59,7 @@ debug_transfer_to_handler:
mfspr r0,SPRN_CSRR1
stw r0,_CSRR1(r11)
/* fall through */
_ASM_NOKPROBE_SYMBOL(debug_transfer_to_handler)
.globl crit_transfer_to_handler
crit_transfer_to_handler:
@ -93,6 +95,7 @@ crit_transfer_to_handler:
rlwinm r0,r1,0,0,(31 - THREAD_SHIFT)
stw r0,KSP_LIMIT(r8)
/* fall through */
_ASM_NOKPROBE_SYMBOL(crit_transfer_to_handler)
#endif
#ifdef CONFIG_40x
@ -114,6 +117,7 @@ crit_transfer_to_handler:
rlwinm r0,r1,0,0,(31 - THREAD_SHIFT)
stw r0,KSP_LIMIT(r8)
/* fall through */
_ASM_NOKPROBE_SYMBOL(crit_transfer_to_handler)
#endif
/*
@ -126,6 +130,7 @@ crit_transfer_to_handler:
.globl transfer_to_handler_full
transfer_to_handler_full:
SAVE_NVGPRS(r11)
_ASM_NOKPROBE_SYMBOL(transfer_to_handler_full)
/* fall through */
.globl transfer_to_handler
@ -226,6 +231,23 @@ transfer_to_handler_cont:
SYNC
RFI /* jump to handler, enable MMU */
#if defined (CONFIG_PPC_BOOK3S_32) || defined(CONFIG_E500)
4: rlwinm r12,r12,0,~_TLF_NAPPING
stw r12,TI_LOCAL_FLAGS(r2)
b power_save_ppc32_restore
7: rlwinm r12,r12,0,~_TLF_SLEEPING
stw r12,TI_LOCAL_FLAGS(r2)
lwz r9,_MSR(r11) /* if sleeping, clear MSR.EE */
rlwinm r9,r9,0,~MSR_EE
lwz r12,_LINK(r11) /* and return to address in LR */
kuap_restore r11, r2, r3, r4, r5
lwz r2, GPR2(r11)
b fast_exception_return
#endif
_ASM_NOKPROBE_SYMBOL(transfer_to_handler)
_ASM_NOKPROBE_SYMBOL(transfer_to_handler_cont)
#ifdef CONFIG_TRACE_IRQFLAGS
1: /* MSR is changing, re-enable MMU so we can notify lockdep. We need to
* keep interrupts disabled at this point otherwise we might risk
@ -271,21 +293,6 @@ reenable_mmu:
bctr /* jump to handler */
#endif /* CONFIG_TRACE_IRQFLAGS */
#if defined (CONFIG_PPC_BOOK3S_32) || defined(CONFIG_E500)
4: rlwinm r12,r12,0,~_TLF_NAPPING
stw r12,TI_LOCAL_FLAGS(r2)
b power_save_ppc32_restore
7: rlwinm r12,r12,0,~_TLF_SLEEPING
stw r12,TI_LOCAL_FLAGS(r2)
lwz r9,_MSR(r11) /* if sleeping, clear MSR.EE */
rlwinm r9,r9,0,~MSR_EE
lwz r12,_LINK(r11) /* and return to address in LR */
kuap_restore r11, r2, r3, r4, r5
lwz r2, GPR2(r11)
b fast_exception_return
#endif
#ifndef CONFIG_VMAP_STACK
/*
* On kernel stack overflow, load up an initial stack pointer