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

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 ee4f2ea48674 ("[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

diff --git a/arch/powerpc/mm/book3s32/hash_low.S b/arch/powerpc/mm/book3s32/hash_low.S
index b2c912e..48415c8 100644 (file)
--- a/arch/powerpc/mm/book3s32/hash_low.S
+++ b/arch/powerpc/mm/book3s32/hash_low.S
@@ -411,30 +411,14 @@ END_FTR_SECTION_IFCLR(CPU_FTR_NEED_COHERENT)
         * and we know there is a definite (although small) speed
         * advantage to putting the PTE in the primary PTEG, we always
         * 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)
        addi    r6,r6,HPTE_SIZE                 /* search for candidate */
        andi.   r6,r6,7*HPTE_SIZE
        stw     r6,next_slot@l(r4)
        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
        /* Store PTE in PTEG */

diff --git a/arch/powerpc/mm/book3s32/mmu.c b/arch/powerpc/mm/book3s32/mmu.c
index 5c60dca..23f60e9 100644 (file)
--- a/arch/powerpc/mm/book3s32/mmu.c
+++ b/arch/powerpc/mm/book3s32/mmu.c
@@ -302,7 +302,7 @@ void __init setbat(int index, unsigned long virt, phys_addr_t phys,
 /*
  * 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;
 

diff --git a/arch/powerpc/mm/mmu_decl.h b/arch/powerpc/mm/mmu_decl.h
index 1b6d39e..0ad6d47 100644 (file)
--- a/arch/powerpc/mm/mmu_decl.h
+++ b/arch/powerpc/mm/mmu_decl.h
@@ -91,8 +91,6 @@ void print_system_hash_info(void);
 
 #ifdef CONFIG_PPC32
 
-void hash_preload(struct mm_struct *mm, unsigned long ea);
-
 extern void mapin_ram(void);
 extern void setbat(int index, unsigned long virt, phys_addr_t phys,
                   unsigned int size, pgprot_t prot);

diff --git a/arch/powerpc/mm/pgtable_32.c b/arch/powerpc/mm/pgtable_32.c
index 888b971..e0ec67a 100644 (file)
--- a/arch/powerpc/mm/pgtable_32.c
+++ b/arch/powerpc/mm/pgtable_32.c
@@ -112,10 +112,6 @@ static void __init __mapin_ram_chunk(unsigned long offset, unsigned long top)
                ktext = ((char *)v >= _stext && (char *)v < etext) ||
                        ((char *)v >= _sinittext && (char *)v < _einittext);
                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;
                p += PAGE_SIZE;
        }