Commit f76c8f6d authored by Christophe Leroy's avatar Christophe Leroy Committed by Michael Ellerman
Browse files

powerpc/8xx: Add function to set pinned TLBs 



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: default avatarChristophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/c17806014bb1c06513ad1e1d510faea31984b177.1589866984.git.christophe.leroy@csgroup.eu
parent 5d465669

arch/powerpc/include/asm/nohash/32/mmu-8xx.h

+2 −0
Original line number Diff line number Diff line
@@ -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;

arch/powerpc/kernel/head_8xx.S

+103 −0
Original line number Diff line number Diff line
@@ -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.

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