As we kexec across kernels that use AMR/IAMR for different purposes
we need to ensure that new kernels get kexec'd with a reset value
of AMR/IAMR. For ex: the new kernel can 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 <aneesh.ku...@linux.ibm.com>
---
.../powerpc/include/asm/book3s/64/kup-radix.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-radix.h
b/arch/powerpc/include/asm/book3s/64/kup-radix.h
index 3ee1ec60be84..c57063c35833 100644
--- a/arch/powerpc/include/asm/book3s/64/kup-radix.h
+++ b/arch/powerpc/include/asm/book3s/64/kup-radix.h
@@ -180,6 +180,26 @@ static inline unsigned long kuap_get_and_check_amr(void)
}
#endif /* CONFIG_PPC_KUAP */
+#define reset_kuap reset_kuap
+static inline void reset_kuap(void)
+{
+ if (mmu_has_feature(MMU_FTR_RADIX_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_RADIX_H */
diff --git a/arch/powerpc/include/asm/kup.h b/arch/powerpc/include/asm/kup.h
index c745ee41ad66..4dc23a706910 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
