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powerpc/603: Inconditionally use task PGDIR in ITLB misses

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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
This commit is contained in:
Christophe Leroy 2024-08-20 19:23:57 +02:00 committed by Michael Ellerman
parent 31c0e137ec
commit 3f57d90c23
1 changed files with 6 additions and 13 deletions
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19
arch/powerpc/kernel/head_book3s_32.S
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@ -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
#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 */
#endif
112: rlwimi r2,r0,12,20,29 /* insert top 10 bits of address */
rlwimi r2,r0,12,20,29 /* insert top 10 bits of address */
lwz r2,0(r2) /* get pmd entry */
#ifdef CONFIG_EXECMEM
rlwinm r3, r0, 4, 0xf
subi r3, r3, (TASK_SIZE >> 28) & 0xf
#endif
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 */