Pinned TLBs are not easy to modify when the MMU is enabled.
Create a small function to update a pinned TLB entry with MMU off.
Signed-off-by: Christophe Leroy <christophe.le...@c-s.fr>
---
arch/powerpc/include/asm/nohash/32/mmu-8xx.h | 3 ++
arch/powerpc/kernel/head_8xx.S | 44 ++++++++++++++++++++
2 files changed, 47 insertions(+)
diff --git a/arch/powerpc/include/asm/nohash/32/mmu-8xx.h
b/arch/powerpc/include/asm/nohash/32/mmu-8xx.h
index a092e6434bda..794bce83c5b0 100644
--- a/arch/powerpc/include/asm/nohash/32/mmu-8xx.h
+++ b/arch/powerpc/include/asm/nohash/32/mmu-8xx.h
@@ -193,6 +193,9 @@
#include <linux/mmdebug.h>
+void mpc8xx_update_tlb(int data, int idx, unsigned long epn,
+ unsigned long twc, unsigned long rpn);
+
typedef struct {
unsigned int id;
unsigned int active;
diff --git a/arch/powerpc/kernel/head_8xx.S b/arch/powerpc/kernel/head_8xx.S
index 423465b10c82..84b3c7692b37 100644
--- a/arch/powerpc/kernel/head_8xx.S
+++ b/arch/powerpc/kernel/head_8xx.S
@@ -866,6 +866,50 @@ initial_mmu:
mtspr SPRN_DER, r8
blr
+/*
+ * void mpc8xx_update_tlb(int data, int idx, unsigned long epn,
+ * unsigned long twc, unsigned long rpn);
+ */
+_GLOBAL(mpc8xx_update_tlb)
+ lis r9, (1f - PAGE_OFFSET)@h
+ ori r9, r9, (1f - PAGE_OFFSET)@l
+ mfmsr r10
+ mflr r11
+ li r12, MSR_KERNEL & ~(MSR_IR | MSR_DR)
+ rlwinm r0, r10, 0, ~MSR_RI
+ rlwinm r0, r0, 0, ~MSR_EE
+ mtmsr r0
+ isync
+ .align 4
+ mtspr SPRN_SRR0, r9
+ mtspr SPRN_SRR1, r12
+ rfi
+
+1: cmpwi r3, 0
+ beq 2f
+
+ mfspr r0, SPRN_MD_CTR
+ rlwimi r0, r4, 8, 0x00001f00
+ mtspr SPRN_MD_CTR, r0
+
+ mtspr SPRN_MD_EPN, r5
+ mtspr SPRN_MD_TWC, r6
+ mtspr SPRN_MD_RPN, r7
+ b 3f
+
+2: mfspr r0, SPRN_MI_CTR
+ rlwimi r0, r4, 8, 0x00001f00
+ mtspr SPRN_MI_CTR, r0
+
+ mtspr SPRN_MI_EPN, r5
+ mtspr SPRN_MI_TWC, r6
+ mtspr SPRN_MI_RPN, r7
+
+3: li r12, MSR_KERNEL & ~(MSR_IR | MSR_DR | MSR_RI)
+ mtmsr r12
+ mtspr SPRN_SRR1, r10
+ mtspr SPRN_SRR0, r11
+ rfi
/*
* We put a few things here that have to be page-aligned.
--
2.25.0
