Messages in this thread | | | Subject | Re: [PATCH 10/12] powerpc/entry32: Blacklist exception entry points for kprobe. | From | Christophe Leroy <> | Date | Mon, 30 Mar 2020 20:33:23 +0200 |
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Le 30/03/2020 à 19:08, Naveen N. Rao a écrit : > Christophe Leroy wrote: >> kprobe does not handle events happening in real mode. >> >> As exception entry points are running with MMU disabled, >> blacklist them. >> >> Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> >> --- >> arch/powerpc/kernel/entry_32.S | 7 +++++++ >> 1 file changed, 7 insertions(+) >> >> diff --git a/arch/powerpc/kernel/entry_32.S >> b/arch/powerpc/kernel/entry_32.S >> index 94f78c03cb79..9a1a45d6038a 100644 >> --- a/arch/powerpc/kernel/entry_32.S >> +++ b/arch/powerpc/kernel/entry_32.S >> @@ -51,6 +51,7 @@ 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: >> @@ -59,6 +60,7 @@ 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: >> @@ -94,6 +96,7 @@ 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 >> @@ -115,6 +118,7 @@ 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 >> >> /* >> @@ -127,6 +131,7 @@ 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 >> @@ -286,6 +291,8 @@ reenable_mmu: >> lwz r2, GPR2(r11) >> b fast_exception_return >> #endif >> +_ASM_NOKPROBE_SYMBOL(transfer_to_handler) >> +_ASM_NOKPROBE_SYMBOL(transfer_to_handler_cont) > > These are added after 'reenable_mmu', which is itself not blacklisted. > Is that intentional?
Yes I put it as the complete end of the entry part, ie just before stack_ovf which is a function by itself.
Note that reenable_mmu is inside an #ifdef CONFIG_TRACE_IRQFLAGS.
I'm not completely sure where to put the _ASM_NOKPROBE_SYMBOL()s, that's the reason why I put it close to the symbol itself in my first series.
Could you have a look at the code and tell me what looks the most appropriate as a location to you ?
https://elixir.bootlin.com/linux/v5.6/source/arch/powerpc/kernel/entry_32.S#L230
Thanks Christophe
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