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powerpc/32s: Don't hash_preload() kernel text

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We now always map kernel text with BATs. Neither need to preload
hash with kernel text addresses nor ensure they are never evicted.

This is more or less a revert of commit ee4f2ea486 ("[POWERPC] Fix
32-bit mm operations when not using BATs")

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/0a0bab7fadd89aa829e33420fbc10d60c59040a7.1606285014.git.christophe.leroy@csgroup.eu
This commit is contained in:
Christophe Leroy 2020-11-25 07:10:47 +00:00 • committed by Michael Ellerman
parent 035b19a15a
commit 79d1befe05
4 changed files with 2 additions and 24 deletions
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18
arch/powerpc/mm/book3s32/hash_low.S
View file

@ -411,30 +411,14 @@ END_FTR_SECTION_IFCLR(CPU_FTR_NEED_COHERENT)
* and we know there is a definite (although small) speed * and we know there is a definite (although small) speed
* advantage to putting the PTE in the primary PTEG, we always * advantage to putting the PTE in the primary PTEG, we always
* put the PTE in the primary PTEG. * put the PTE in the primary PTEG.
*
* In addition, we skip any slot that is mapping kernel text in
* order to avoid a deadlock when not using BAT mappings if
* trying to hash in the kernel hash code itself after it has
* already taken the hash table lock. This works in conjunction
* with pre-faulting of the kernel text.
*
* If the hash table bucket is full of kernel text entries, we'll
* lockup here but that shouldn't happen
*/ */
1: lis r4, (next_slot - PAGE_OFFSET)@ha /* get next evict slot */ lis r4, (next_slot - PAGE_OFFSET)@ha /* get next evict slot */
lwz r6, (next_slot - PAGE_OFFSET)@l(r4) lwz r6, (next_slot - PAGE_OFFSET)@l(r4)
addi r6,r6,HPTE_SIZE /* search for candidate */ addi r6,r6,HPTE_SIZE /* search for candidate */
andi. r6,r6,7*HPTE_SIZE andi. r6,r6,7*HPTE_SIZE
stw r6,next_slot@l(r4) stw r6,next_slot@l(r4)
add r4,r3,r6 add r4,r3,r6
LDPTE r0,HPTE_SIZE/2(r4) /* get PTE second word */
clrrwi r0,r0,12
lis r6,etext@h
ori r6,r6,etext@l /* get etext */
tophys(r6,r6)
cmpl cr0,r0,r6 /* compare and try again */
blt 1b
#ifndef CONFIG_SMP #ifndef CONFIG_SMP
/* Store PTE in PTEG */ /* Store PTE in PTEG */

2
arch/powerpc/mm/book3s32/mmu.c
View file

@ -302,7 +302,7 @@ void __init setbat(int index, unsigned long virt, phys_addr_t phys,
/* /*
* Preload a translation in the hash table * Preload a translation in the hash table
*/ */
void hash_preload(struct mm_struct *mm, unsigned long ea) static void hash_preload(struct mm_struct *mm, unsigned long ea)
{ {
pmd_t *pmd; pmd_t *pmd;

2
arch/powerpc/mm/mmu_decl.h
View file

@ -91,8 +91,6 @@ void print_system_hash_info(void);
#ifdef CONFIG_PPC32 #ifdef CONFIG_PPC32
void hash_preload(struct mm_struct *mm, unsigned long ea);
extern void mapin_ram(void); extern void mapin_ram(void);
extern void setbat(int index, unsigned long virt, phys_addr_t phys, extern void setbat(int index, unsigned long virt, phys_addr_t phys,
unsigned int size, pgprot_t prot); unsigned int size, pgprot_t prot);

4
arch/powerpc/mm/pgtable_32.c
View file

@ -112,10 +112,6 @@ static void __init __mapin_ram_chunk(unsigned long offset, unsigned long top)
ktext = ((char *)v >= _stext && (char *)v < etext) || ktext = ((char *)v >= _stext && (char *)v < etext) ||
((char *)v >= _sinittext && (char *)v < _einittext); ((char *)v >= _sinittext && (char *)v < _einittext);
map_kernel_page(v, p, ktext ? PAGE_KERNEL_TEXT : PAGE_KERNEL); map_kernel_page(v, p, ktext ? PAGE_KERNEL_TEXT : PAGE_KERNEL);
#ifdef CONFIG_PPC_BOOK3S_32
if (ktext)
hash_preload(&init_mm, v);
#endif
v += PAGE_SIZE; v += PAGE_SIZE;
p += PAGE_SIZE; p += PAGE_SIZE;
} }