From: Christophe Leroy (CS GROUP) Date: Fri, 19 Dec 2025 12:23:52 +0000 (+0100) Subject: powerpc/32: Restore disabling of interrupts at interrupt/syscall exit X-Git-Tag: v6.19-rc3~5^2 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=608328ba5b0619cbc28b409296b5e3840bcb97b6;p=thirdparty%2Flinux.git powerpc/32: Restore disabling of interrupts at interrupt/syscall exit Commit 2997876c4a1a ("powerpc/32: Restore clearing of MSR[RI] at interrupt/syscall exit") delayed clearing of MSR[RI], but missed that both MSR[RI] and MSR[EE] are cleared at the same time, so the commit also delayed the disabling of interrupts, leading to unexpected behaviour. To fix that, mostly revert the blamed commit and restore the clearing of MSR[RI] in interrupt_exit_kernel_prepare() instead. For 8xx it implies adding a synchronising instruction after the mtspr in order to make sure no instruction counter interrupt (used for perf events) will fire just after clearing MSR[RI]. Reported-by: Christian Zigotzky Closes: https://lore.kernel.org/all/4d0bd05d-6158-1323-3509-744d3fbe8fc7@xenosoft.de/ Reported-by: Guenter Roeck Closes: https://lore.kernel.org/all/6b05eb1c-fdef-44e0-91a7-8286825e68f1@roeck-us.net/ Fixes: 2997876c4a1a ("powerpc/32: Restore clearing of MSR[RI] at interrupt/syscall exit") Signed-off-by: Christophe Leroy (CS GROUP) Signed-off-by: Madhavan Srinivasan Link: https://patch.msgid.link/585ea521b2be99d293b539bbfae148366cfb3687.1766146895.git.chleroy@kernel.org --- diff --git a/arch/powerpc/include/asm/hw_irq.h b/arch/powerpc/include/asm/hw_irq.h index 1078ba88efaf4..9cd945f2acafa 100644 --- a/arch/powerpc/include/asm/hw_irq.h +++ b/arch/powerpc/include/asm/hw_irq.h @@ -90,7 +90,7 @@ static inline void __hard_EE_RI_disable(void) if (IS_ENABLED(CONFIG_BOOKE)) wrtee(0); else if (IS_ENABLED(CONFIG_PPC_8xx)) - wrtspr(SPRN_NRI); + wrtspr_sync(SPRN_NRI); else if (IS_ENABLED(CONFIG_PPC_BOOK3S_64)) __mtmsrd(0, 1); else diff --git a/arch/powerpc/include/asm/reg.h b/arch/powerpc/include/asm/reg.h index 3fe1866354323..3449dd2b577d4 100644 --- a/arch/powerpc/include/asm/reg.h +++ b/arch/powerpc/include/asm/reg.h @@ -1400,6 +1400,7 @@ static inline void mtmsr_isync(unsigned long val) : "r" ((unsigned long)(v)) \ : "memory") #define wrtspr(rn) asm volatile("mtspr " __stringify(rn) ",2" : : : "memory") +#define wrtspr_sync(rn) asm volatile("mtspr " __stringify(rn) ",2; sync" : : : "memory") static inline void wrtee(unsigned long val) { diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S index 16f8ee6cb2cd6..d8426251b1cda 100644 --- a/arch/powerpc/kernel/entry_32.S +++ b/arch/powerpc/kernel/entry_32.S @@ -101,17 +101,6 @@ SYM_FUNC_END(__kuep_unlock) .endm #endif -.macro clr_ri trash -#ifndef CONFIG_BOOKE -#ifdef CONFIG_PPC_8xx - mtspr SPRN_NRI, \trash -#else - li \trash, MSR_KERNEL & ~MSR_RI - mtmsr \trash -#endif -#endif -.endm - .globl transfer_to_syscall transfer_to_syscall: stw r3, ORIG_GPR3(r1) @@ -160,7 +149,6 @@ ret_from_syscall: cmpwi r3,0 REST_GPR(3, r1) syscall_exit_finish: - clr_ri r4 mtspr SPRN_SRR0,r7 mtspr SPRN_SRR1,r8 @@ -237,7 +225,6 @@ fast_exception_return: /* Clear the exception marker on the stack to avoid confusing stacktrace */ li r10, 0 stw r10, 8(r11) - clr_ri r10 mtspr SPRN_SRR1,r9 mtspr SPRN_SRR0,r12 REST_GPR(9, r11) @@ -270,7 +257,6 @@ interrupt_return: .Lfast_user_interrupt_return: lwz r11,_NIP(r1) lwz r12,_MSR(r1) - clr_ri r4 mtspr SPRN_SRR0,r11 mtspr SPRN_SRR1,r12 @@ -313,7 +299,6 @@ END_FTR_SECTION_IFSET(CPU_FTR_NEED_PAIRED_STWCX) cmpwi cr1,r3,0 lwz r11,_NIP(r1) lwz r12,_MSR(r1) - clr_ri r4 mtspr SPRN_SRR0,r11 mtspr SPRN_SRR1,r12 diff --git a/arch/powerpc/kernel/interrupt.c b/arch/powerpc/kernel/interrupt.c index aea6f7e8e9c67..e63bfde13e031 100644 --- a/arch/powerpc/kernel/interrupt.c +++ b/arch/powerpc/kernel/interrupt.c @@ -38,7 +38,7 @@ static inline bool exit_must_hard_disable(void) #else static inline bool exit_must_hard_disable(void) { - return false; + return true; } #endif @@ -443,6 +443,9 @@ again: if (unlikely(stack_store)) __hard_EE_RI_disable(); +#else + } else { + __hard_EE_RI_disable(); #endif /* CONFIG_PPC64 */ }