From a616c442119f2ea5641e6abc215d7255b73b982b Mon Sep 17 00:00:00 2001 From: Christophe Leroy Date: Tue, 31 Mar 2020 16:03:45 +0000 Subject: [PATCH] powerpc/entry32: Blacklist exception entry points for kprobe. 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 Acked-by: Naveen N. Rao Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/f61ac599855e674ebb592464d0ea32a3ba9c6644.1585670437.git.christophe.leroy@c-s.fr --- arch/powerpc/kernel/entry_32.S | 37 ++++++++++++++++++++++--------------- 1 file changed, 22 insertions(+), 15 deletions(-) diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S index d54f40650ff8..c9fc6ea36bc6 100644 --- a/arch/powerpc/kernel/entry_32.S +++ b/arch/powerpc/kernel/entry_32.S @@ -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 -- 2.11.0