powerpc/603: Inconditionally use task PGDIR in ITLB misses

Now that modules exec page tables are preallocated, the instruction
TLBmiss handler can use task PGDIR inconditionally.

Also revise the identification of user vs kernel user space by doing
a calculation instead of a comparison: Get the segment number and
subtract the number of the first kernel segment. The result is
positive for kernel addresses and negative for user addresses,
which means that upper 2 bits are 0 for kernel and 3 for user.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/9a3242162ad2faab8019c698e501b326a126ee9e.1724173828.git.christophe.leroy@csgroup.eu

diff --git a/arch/powerpc/kernel/head_book3s_32.S b/arch/powerpc/kernel/head_book3s_32.S
index 7995506e7fbd7b752b6407352d0a212e79187e56..156304c00ecead739256fe3ca3b94ae88af11633 100644 (file)
--- a/arch/powerpc/kernel/head_book3s_32.S
+++ b/arch/powerpc/kernel/head_book3s_32.S
@@ -413,22 +413,15 @@ END_FTR_SECTION_IFSET(CPU_FTR_FPU_UNAVAILABLE)
 InstructionTLBMiss:
        /* Get PTE (linux-style) and check access */
        mfspr   r0,SPRN_IMISS
-#ifdef CONFIG_EXECMEM
-       lis     r1, TASK_SIZE@h         /* check if kernel address */
-       cmplw   0,r1,r0
-#endif
        mfspr   r2, SPRN_SDR1
        li      r1,_PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_EXEC
        rlwinm  r2, r2, 28, 0xfffff000
+       rlwimi  r2,r0,12,20,29          /* insert top 10 bits of address */
+       lwz     r2,0(r2)                /* get pmd entry */
 #ifdef CONFIG_EXECMEM
-       li      r3, 3
-       bgt-    112f
-       lis     r2, (swapper_pg_dir - PAGE_OFFSET)@ha   /* if kernel address, use */
-       li      r3, 0
-       addi    r2, r2, (swapper_pg_dir - PAGE_OFFSET)@l        /* kernel page table */
+       rlwinm  r3, r0, 4, 0xf
+       subi    r3, r3, (TASK_SIZE >> 28) & 0xf
 #endif
-112:   rlwimi  r2,r0,12,20,29          /* insert top 10 bits of address */
-       lwz     r2,0(r2)                /* get pmd entry */
        rlwinm. r2,r2,0,0,19            /* extract address of pte page */
        beq-    InstructionAddressInvalid       /* return if no mapping */
        rlwimi  r2,r0,22,20,29          /* insert next 10 bits of address */
@@ -437,7 +430,7 @@ InstructionTLBMiss:
        bne-    InstructionAddressInvalid /* return if access not permitted */
        /* Convert linux-style PTE to low word of PPC-style PTE */
 #ifdef CONFIG_EXECMEM
-       rlwimi  r2, r3, 0, 31, 31       /* userspace ? -> PP lsb */
+       rlwimi  r2, r3, 1, 31, 31       /* userspace ? -> PP lsb */
 #endif
        ori     r1, r1, 0xe06           /* clear out reserved bits */
        andc    r1, r2, r1              /* PP = user? 1 : 0 */