Merge branch 'for-linus' of master.kernel.org:/pub/scm/linux/kernel/git/roland/infiniband

[sfrench/cifs-2.6.git] / arch / powerpc / mm / hash_low_32.S

diff --git a/arch/powerpc/mm/hash_low_32.S b/arch/powerpc/mm/hash_low_32.S
index 94255beeecd371bec3df12f5212b9fe85c9e47ec..ddceefc06ecc0a5554a650e5dbe690959274943a 100644 (file)
--- a/arch/powerpc/mm/hash_low_32.S
+++ b/arch/powerpc/mm/hash_low_32.S
@@ -21,7 +21,6 @@
  *
  */
 
-#include <linux/config.h>
 #include <asm/reg.h>
 #include <asm/page.h>
 #include <asm/pgtable.h>
@@ -284,6 +283,7 @@ Hash_msk = (((1 << Hash_bits) - 1) * 64)
 #define PTEG_SIZE      64
 #define LG_PTEG_SIZE   6
 #define LDPTEu         lwzu
+#define LDPTE          lwz
 #define STPTE          stw
 #define CMPPTE         cmpw
 #define PTE_H          0x40
@@ -390,13 +390,30 @@ _GLOBAL(hash_page_patch_C)
         * 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
         */
-       addis   r4,r7,next_slot@ha
+
+1:     addis   r4,r7,next_slot@ha              /* get next evict slot */
        lwz     r6,next_slot@l(r4)
-       addi    r6,r6,PTE_SIZE
+       addi    r6,r6,PTE_SIZE                  /* search for candidate */
        andi.   r6,r6,7*PTE_SIZE
        stw     r6,next_slot@l(r4)
        add     r4,r3,r6
+       LDPTE   r0,PTE_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 */