Commit 3f57d90c authored by Christophe Leroy's avatar Christophe Leroy Committed by Michael Ellerman
Browse files

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: default avatarChristophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/9a3242162ad2faab8019c698e501b326a126ee9e.1724173828.git.christophe.leroy@csgroup.eu
parent 31c0e137

arch/powerpc/kernel/head_book3s_32.S

+5 −12
Original line number Diff line number Diff line
@@ -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 */