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Mon, 15 Jun 2020 06:16:33 +0000 (GMT) Received: from b03ledav006.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id E5D3FC605B; Mon, 15 Jun 2020 06:16:31 +0000 (GMT) Received: from skywalker.ibmuc.com (unknown [9.102.2.91]) by b03ledav006.gho.boulder.ibm.com (Postfix) with ESMTP; Mon, 15 Jun 2020 06:16:31 +0000 (GMT) From: "Aneesh Kumar K.V" To: linuxppc-dev@lists.ozlabs.org, mpe@ellerman.id.au Subject: [PATCH v4 40/41] powerpc/book3s64/keys/kuap: Reset AMR/IAMR values on kexec Date: Mon, 15 Jun 2020 11:44:29 +0530 Message-Id: <20200615061430.770174-41-aneesh.kumar@linux.ibm.com> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200615061430.770174-1-aneesh.kumar@linux.ibm.com> References: <20200615061430.770174-1-aneesh.kumar@linux.ibm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.216, 18.0.687 definitions=2020-06-15_01:2020-06-12, 2020-06-15 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 mlxlogscore=999 clxscore=1015 priorityscore=1501 adultscore=0 bulkscore=0 malwarescore=0 mlxscore=0 lowpriorityscore=0 spamscore=0 impostorscore=0 cotscore=-2147483648 phishscore=0 suspectscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2004280000 definitions=main-2006150050 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: "Aneesh Kumar K.V" , linuxram@us.ibm.com, bauerman@linux.ibm.com Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" We can kexec into a kernel that doesn't use memory keys for kernel mapping (such as an older kernel which doesn't support kuap/kuep with hash translation). We need to make sure we reset the AMR/IAMR value on kexec otherwise, the new kernel will use key 0 for kernel mapping and the old AMR value prevents access to key 0. This patch also removes reset if IAMR and AMOR in kexec_sequence. Reset of AMOR is not needed and the IAMR reset is partial (it doesn't do the reset on secondary cpus) and is redundant with this patch. Signed-off-by: Aneesh Kumar K.V --- arch/powerpc/include/asm/book3s/64/kup.h | 20 ++++++++++++++++++++ arch/powerpc/include/asm/kup.h | 14 ++++++++++++++ arch/powerpc/kernel/misc_64.S | 14 -------------- arch/powerpc/kexec/core_64.c | 3 +++ arch/powerpc/mm/book3s64/pgtable.c | 3 +++ 5 files changed, 40 insertions(+), 14 deletions(-) diff --git a/arch/powerpc/include/asm/book3s/64/kup.h b/arch/powerpc/include/asm/book3s/64/kup.h index 78b3f67ae8c5..be04733c89f3 100644 --- a/arch/powerpc/include/asm/book3s/64/kup.h +++ b/arch/powerpc/include/asm/book3s/64/kup.h @@ -365,6 +365,26 @@ static inline bool bad_kuap_fault(struct pt_regs *regs, unsigned long address, } #endif /* CONFIG_PPC_KUAP */ +#define reset_kuap reset_kuap +static inline void reset_kuap(void) +{ + if (mmu_has_feature(MMU_FTR_KUAP)) { + mtspr(SPRN_AMR, 0); + /* Do we need isync()? We are going via a kexec reset */ + isync(); + } +} + +#define reset_kuep reset_kuep +static inline void reset_kuep(void) +{ + if (mmu_has_feature(MMU_FTR_KUEP)) { + mtspr(SPRN_IAMR, 0); + /* Do we need isync()? We are going via a kexec reset */ + isync(); + } +} + #endif /* __ASSEMBLY__ */ #endif /* _ASM_POWERPC_BOOK3S_64_KUP_H */ diff --git a/arch/powerpc/include/asm/kup.h b/arch/powerpc/include/asm/kup.h index a29f69bbf6ec..c7ab7310f230 100644 --- a/arch/powerpc/include/asm/kup.h +++ b/arch/powerpc/include/asm/kup.h @@ -113,6 +113,20 @@ static inline void prevent_current_write_to_user(void) prevent_user_access(NULL, NULL, ~0UL, KUAP_CURRENT_WRITE); } +#ifndef reset_kuap +#define reset_kuap reset_kuap +static inline void reset_kuap(void) +{ +} +#endif + +#ifndef reset_kuep +#define reset_kuep reset_kuep +static inline void reset_kuep(void) +{ +} +#endif + #endif /* !__ASSEMBLY__ */ #endif /* _ASM_POWERPC_KUAP_H_ */ diff --git a/arch/powerpc/kernel/misc_64.S b/arch/powerpc/kernel/misc_64.S index 1864605eca29..7bb46ad98207 100644 --- a/arch/powerpc/kernel/misc_64.S +++ b/arch/powerpc/kernel/misc_64.S @@ -413,20 +413,6 @@ _GLOBAL(kexec_sequence) li r0,0 std r0,16(r1) -BEGIN_FTR_SECTION - /* - * This is the best time to turn AMR/IAMR off. - * key 0 is used in radix for supervisor<->user - * protection, but on hash key 0 is reserved - * ideally we want to enter with a clean state. - * NOTE, we rely on r0 being 0 from above. - */ - mtspr SPRN_IAMR,r0 -BEGIN_FTR_SECTION_NESTED(42) - mtspr SPRN_AMOR,r0 -END_FTR_SECTION_NESTED_IFSET(CPU_FTR_HVMODE, 42) -END_FTR_SECTION_IFSET(CPU_FTR_ARCH_300) - /* save regs for local vars on new stack. * yes, we won't go back, but ... */ diff --git a/arch/powerpc/kexec/core_64.c b/arch/powerpc/kexec/core_64.c index b4184092172a..a124715f33ea 100644 --- a/arch/powerpc/kexec/core_64.c +++ b/arch/powerpc/kexec/core_64.c @@ -152,6 +152,9 @@ static void kexec_smp_down(void *arg) if (ppc_md.kexec_cpu_down) ppc_md.kexec_cpu_down(0, 1); + reset_kuap(); + reset_kuep(); + kexec_smp_wait(); /* NOTREACHED */ } diff --git a/arch/powerpc/mm/book3s64/pgtable.c b/arch/powerpc/mm/book3s64/pgtable.c index c58ad1049909..9673f4b74c9a 100644 --- a/arch/powerpc/mm/book3s64/pgtable.c +++ b/arch/powerpc/mm/book3s64/pgtable.c @@ -165,6 +165,9 @@ void mmu_cleanup_all(void) radix__mmu_cleanup_all(); else if (mmu_hash_ops.hpte_clear_all) mmu_hash_ops.hpte_clear_all(); + + reset_kuap(); + reset_kuep(); } #ifdef CONFIG_MEMORY_HOTPLUG -- 2.26.2