Pinned TLBs cannot be modified when the MMU is enabled.
Create a function to rewrite the pinned TLB entries with MMU off.
To set pinned TLB, we have to turn off MMU, disable pinning,
do a TLB flush (Either with tlbie and tlbia) then reprogam
the TLB entries, enable pinning and turn on MMU.
If using tlbie, it cleared entries in both instruction and data
TLB regardless whether pinning is disabled or not.
If using tlbia, it clears all entries of the TLB which has
disabled pinning.
To make it easy, just clear all entries in both TLBs, and
reprogram them.
The function takes two arguments, the top of the memory to
consider and whether data is RO under _sinittext.
When DEBUG_PAGEALLOC is set, the top is the end of kernel rodata.
Otherwise, that's the top of physical RAM.
Everything below _sinittext is set RX, over _sinittext that's RW.
Signed-off-by: Christophe Leroy <christophe.le...@csgroup.eu>
---
v2: Function rewritten to manage all entries at once.
---
arch/powerpc/include/asm/nohash/32/mmu-8xx.h | 2 +
arch/powerpc/kernel/head_8xx.S | 103 +++++++++++++++++++
2 files changed, 105 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..4d3ef3841b00 100644
--- a/arch/powerpc/include/asm/nohash/32/mmu-8xx.h
+++ b/arch/powerpc/include/asm/nohash/32/mmu-8xx.h
@@ -193,6 +193,8 @@
#include <linux/mmdebug.h>
+void mmu_pin_tlb(unsigned long top, bool readonly);
+
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..c9e3d54e6a6f 100644
--- a/arch/powerpc/kernel/head_8xx.S
+++ b/arch/powerpc/kernel/head_8xx.S
@@ -16,6 +16,7 @@
#include <linux/init.h>
#include <linux/magic.h>
+#include <linux/sizes.h>
#include <asm/processor.h>
#include <asm/page.h>
#include <asm/mmu.h>
@@ -866,6 +867,108 @@ initial_mmu:
mtspr SPRN_DER, r8
blr
+#ifdef CONFIG_PIN_TLB
+_GLOBAL(mmu_pin_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 | MSR_RI)
+ 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:
+ li r5, 0
+ lis r6, MD_TWAM@h
+ mtspr SPRN_MI_CTR, r5
+ mtspr SPRN_MD_CTR, r6
+ tlbia
+
+#ifdef CONFIG_PIN_TLB_TEXT
+ LOAD_REG_IMMEDIATE(r5, 28 << 8)
+ LOAD_REG_IMMEDIATE(r6, PAGE_OFFSET)
+ LOAD_REG_IMMEDIATE(r7, MI_SVALID | MI_PS8MEG)
+ LOAD_REG_IMMEDIATE(r8, 0xf0 | _PAGE_RO | _PAGE_SPS | _PAGE_SH |
_PAGE_PRESENT)
+ LOAD_REG_ADDR(r9, _sinittext)
+ li r0, 4
+ mtctr r0
+
+2: ori r0, r6, MI_EVALID
+ mtspr SPRN_MI_CTR, r5
+ mtspr SPRN_MI_EPN, r0
+ mtspr SPRN_MI_TWC, r7
+ mtspr SPRN_MI_RPN, r8
+ addi r5, r5, 0x100
+ addis r6, r6, SZ_8M@h
+ addis r8, r8, SZ_8M@h
+ cmplw r6, r9
+ bdnzt lt, 2b
+ lis r0, MI_RSV4I@h
+ mtspr SPRN_MI_CTR, r0
+#endif
+ LOAD_REG_IMMEDIATE(r5, 28 << 8 | MD_TWAM)
+#ifdef CONFIG_PIN_TLB_DATA
+ LOAD_REG_IMMEDIATE(r6, PAGE_OFFSET)
+ LOAD_REG_IMMEDIATE(r7, MI_SVALID | MI_PS8MEG)
+#ifdef CONFIG_PIN_TLB_IMMR
+ li r0, 3
+#else
+ li r0, 4
+#endif
+ mtctr r0
+ cmpwi r4, 0
+ beq 4f
+ LOAD_REG_IMMEDIATE(r8, 0xf0 | _PAGE_RO | _PAGE_SPS | _PAGE_SH |
_PAGE_PRESENT)
+ LOAD_REG_ADDR(r9, _sinittext)
+
+2: ori r0, r6, MD_EVALID
+ mtspr SPRN_MD_CTR, r5
+ mtspr SPRN_MD_EPN, r0
+ mtspr SPRN_MD_TWC, r7
+ mtspr SPRN_MD_RPN, r8
+ addi r5, r5, 0x100
+ addis r6, r6, SZ_8M@h
+ addis r8, r8, SZ_8M@h
+ cmplw r6, r9
+ bdnzt lt, 2b
+
+4: LOAD_REG_IMMEDIATE(r8, 0xf0 | _PAGE_SPS | _PAGE_SH | _PAGE_PRESENT)
+2: ori r0, r6, MD_EVALID
+ mtspr SPRN_MD_CTR, r5
+ mtspr SPRN_MD_EPN, r0
+ mtspr SPRN_MD_TWC, r7
+ mtspr SPRN_MD_RPN, r8
+ addi r5, r5, 0x100
+ addis r6, r6, SZ_8M@h
+ addis r8, r8, SZ_8M@h
+ cmplw r6, r3
+ bdnzt lt, 2b
+#endif
+#ifdef CONFIG_PIN_TLB_IMMR
+ LOAD_REG_IMMEDIATE(r0, VIRT_IMMR_BASE | MD_EVALID)
+ LOAD_REG_IMMEDIATE(r7, MD_SVALID | MD_PS512K | MD_GUARDED)
+ mfspr r8, SPRN_IMMR
+ rlwinm r8, r8, 0, 0xfff80000
+ ori r8, r8, 0xf0 | _PAGE_DIRTY | _PAGE_SPS | _PAGE_SH | \
+ _PAGE_NO_CACHE | _PAGE_PRESENT
+ mtspr SPRN_MD_CTR, r5
+ mtspr SPRN_MD_EPN, r0
+ mtspr SPRN_MD_TWC, r7
+ mtspr SPRN_MD_RPN, r8
+#endif
+#if defined(CONFIG_PIN_TLB_IMMR) || defined(CONFIG_PIN_TLB_DATA)
+ lis r0, (MD_RSV4I | MD_TWAM)@h
+ mtspr SPRN_MI_CTR, r0
+#endif
+ mtspr SPRN_SRR1, r10
+ mtspr SPRN_SRR0, r11
+ rfi
+#endif /* CONFIG_PIN_TLB */
/*
* We put a few things here that have to be page-aligned.
--
2.25.0
