From: Christophe Leroy Date: Fri, 17 Apr 2020 11:58:36 +0000 (+0000) Subject: powerpc/mm: Fix CONFIG_PPC_KUAP_DEBUG on PPC32 X-Git-Tag: Ubuntu-5.4.0-38.42~765 X-Git-Url: https://git.proxmox.com/?a=commitdiff_plain;h=17f034d94159488ac256bf89df37769219e22e9f;p=mirror_ubuntu-focal-kernel.git powerpc/mm: Fix CONFIG_PPC_KUAP_DEBUG on PPC32 BugLink: https://bugs.launchpad.net/bugs/1876361 commit feb8e960d780e170e992a70491eec9dd68f4dbf2 upstream. CONFIG_PPC_KUAP_DEBUG is not selectable because it depends on PPC_32 which doesn't exists. Fixing it leads to a deadlock due to a vital register getting clobbered in _switch(). Change dependency to PPC32 and use r0 instead of r4 in _switch() Fixes: e2fb9f544431 ("powerpc/32: Prepare for Kernel Userspace Access Protection") Cc: stable@vger.kernel.org # v5.2+ Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/540242f7d4573f7cdf1b3bf46bb35f743b2cd68f.1587124651.git.christophe.leroy@c-s.fr Signed-off-by: Greg Kroah-Hartman Signed-off-by: Kamal Mostafa Signed-off-by: Stefan Bader --- diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S index 13f699256258..f29bb176381f 100644 --- a/arch/powerpc/kernel/entry_32.S +++ b/arch/powerpc/kernel/entry_32.S @@ -705,7 +705,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_SPE) stw r10,_CCR(r1) stw r1,KSP(r3) /* Set old stack pointer */ - kuap_check r2, r4 + kuap_check r2, r0 #ifdef CONFIG_SMP /* We need a sync somewhere here to make sure that if the * previous task gets rescheduled on another CPU, it sees all diff --git a/arch/powerpc/platforms/Kconfig.cputype b/arch/powerpc/platforms/Kconfig.cputype index fa98fa36a4c4..f0330ce498d1 100644 --- a/arch/powerpc/platforms/Kconfig.cputype +++ b/arch/powerpc/platforms/Kconfig.cputype @@ -389,7 +389,7 @@ config PPC_KUAP config PPC_KUAP_DEBUG bool "Extra debugging for Kernel Userspace Access Protection" - depends on PPC_KUAP && (PPC_RADIX_MMU || PPC_32) + depends on PPC_KUAP && (PPC_RADIX_MMU || PPC32) help Add extra debugging for Kernel Userspace Access Protection (KUAP) If you're unsure, say N.