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Message-Id: <4b225168031449fc34fc7132f3923cc8dc54af60.1656427701.git.christophe.leroy@csgroup.eu>
Date: Tue, 28 Jun 2022 16:48:57 +0200
From: Christophe Leroy <christophe.leroy@...roup.eu>
To: Benjamin Herrenschmidt <benh@...nel.crashing.org>,
Paul Mackerras <paulus@...ba.org>,
Michael Ellerman <mpe@...erman.id.au>, dja@...ens.net
Cc: Christophe Leroy <christophe.leroy@...roup.eu>,
linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org
Subject: [PATCH v1 4/6] powerpc/64e: Move virtual memory closer to linear memory
Today nohash/64 have linear memory based at 0xc000000000000000 and
virtual memory based at 0x8000000000000000.
In order to implement KASAN, we need to regroup both areas.
Move virtual memmory at 0xc000100000000000.
This complicates a bit TLB miss handlers. Until now, memory region
was easily identified with the 4 higher bits of address:
- 0 ==> User
- c ==> Linear Memory
- 8 ==> Virtual Memory
Now we need to rely on the 20 higher bits, with:
- 0xxxx ==> User
- c0000 ==> Linear Memory
- c0001 ==> Virtual Memory
Signed-off-by: Christophe Leroy <christophe.leroy@...roup.eu>
---
arch/powerpc/include/asm/nohash/64/pgtable.h | 2 +-
arch/powerpc/mm/nohash/tlb_low_64e.S | 64 +++++++++++---------
2 files changed, 38 insertions(+), 28 deletions(-)
diff --git a/arch/powerpc/include/asm/nohash/64/pgtable.h b/arch/powerpc/include/asm/nohash/64/pgtable.h
index db9770995f7c..76a144b58f9b 100644
--- a/arch/powerpc/include/asm/nohash/64/pgtable.h
+++ b/arch/powerpc/include/asm/nohash/64/pgtable.h
@@ -25,7 +25,7 @@
/*
* Define the address range of the kernel non-linear virtual area
*/
-#define KERN_VIRT_START ASM_CONST(0x8000000000000000)
+#define KERN_VIRT_START ASM_CONST(0xc000100000000000)
#define KERN_VIRT_SIZE ASM_CONST(0x0000100000000000)
/*
diff --git a/arch/powerpc/mm/nohash/tlb_low_64e.S b/arch/powerpc/mm/nohash/tlb_low_64e.S
index a59485c549a7..68ffbfdba894 100644
--- a/arch/powerpc/mm/nohash/tlb_low_64e.S
+++ b/arch/powerpc/mm/nohash/tlb_low_64e.S
@@ -213,10 +213,11 @@ itlb_miss_kernel_bolted:
tlb_miss_kernel_bolted:
mfspr r10,SPRN_MAS1
ld r14,PACA_KERNELPGD(r13)
- cmpldi cr0,r15,8 /* Check for vmalloc region */
+ srdi r15,r16,44 /* get kernel region */
+ andi. r15,r15,1 /* Check for vmalloc region */
rlwinm r10,r10,0,16,1 /* Clear TID */
mtspr SPRN_MAS1,r10
- beq+ tlb_miss_common_bolted
+ bne+ tlb_miss_common_bolted
tlb_miss_fault_bolted:
/* We need to check if it was an instruction miss */
@@ -498,7 +499,9 @@ tlb_miss_huge_e6500:
tlb_miss_kernel_e6500:
ld r14,PACA_KERNELPGD(r13)
- cmpldi cr1,r15,8 /* Check for vmalloc region */
+ srdi r15,r16,44 /* get kernel region */
+ xoris r15,r15,0xc /* Check for vmalloc region */
+ cmplwi cr1,r15,1
beq+ cr1,tlb_miss_common_e6500
tlb_miss_fault_e6500:
@@ -532,16 +535,18 @@ itlb_miss_fault_e6500:
*/
mfspr r14,SPRN_ESR
mfspr r16,SPRN_DEAR /* get faulting address */
- srdi r15,r16,60 /* get region */
- cmpldi cr0,r15,0xc /* linear mapping ? */
+ srdi r15,r16,44 /* get region */
+ xoris r15,r15,0xc
+ cmpldi cr0,r15,0 /* linear mapping ? */
beq tlb_load_linear /* yes -> go to linear map load */
+ cmpldi cr1,r15,1 /* vmalloc mapping ? */
/* The page tables are mapped virtually linear. At this point, though,
* we don't know whether we are trying to fault in a first level
* virtual address or a virtual page table address. We can get that
* from bit 0x1 of the region ID which we have set for a page table
*/
- andi. r10,r15,0x1
+ andis. r10,r15,0x1
bne- virt_page_table_tlb_miss
std r14,EX_TLB_ESR(r12); /* save ESR */
@@ -553,7 +558,7 @@ itlb_miss_fault_e6500:
/* We do the user/kernel test for the PID here along with the RW test
*/
- cmpldi cr0,r15,0 /* Check for user region */
+ srdi. r15,r16,60 /* Check for user region */
/* We pre-test some combination of permissions to avoid double
* faults:
@@ -577,10 +582,9 @@ itlb_miss_fault_e6500:
beq normal_tlb_miss_user
/* XXX replace the RMW cycles with immediate loads + writes */
1: mfspr r10,SPRN_MAS1
- cmpldi cr0,r15,8 /* Check for vmalloc region */
rlwinm r10,r10,0,16,1 /* Clear TID */
mtspr SPRN_MAS1,r10
- beq+ normal_tlb_miss
+ beq+ cr1,normal_tlb_miss
/* We got a crappy address, just fault with whatever DEAR and ESR
* are here
@@ -606,16 +610,18 @@ itlb_miss_fault_e6500:
*
* Faulting address is SRR0 which is already in r16
*/
- srdi r15,r16,60 /* get region */
- cmpldi cr0,r15,0xc /* linear mapping ? */
+ srdi r15,r16,44 /* get region */
+ xoris r15,r15,0xc
+ cmpldi cr0,r15,0 /* linear mapping ? */
beq tlb_load_linear /* yes -> go to linear map load */
+ cmpldi cr1,r15,1 /* vmalloc mapping ? */
/* We do the user/kernel test for the PID here along with the RW test
*/
li r11,_PAGE_PRESENT|_PAGE_BAP_UX /* Base perm */
oris r11,r11,_PAGE_ACCESSED@h
- cmpldi cr0,r15,0 /* Check for user region */
+ srdi. r15,r16,60 /* Check for user region */
std r14,EX_TLB_ESR(r12) /* write crazy -1 to frame */
beq normal_tlb_miss_user
@@ -623,10 +629,9 @@ itlb_miss_fault_e6500:
oris r11,r11,_PAGE_ACCESSED@h
/* XXX replace the RMW cycles with immediate loads + writes */
mfspr r10,SPRN_MAS1
- cmpldi cr0,r15,8 /* Check for vmalloc region */
rlwinm r10,r10,0,16,1 /* Clear TID */
mtspr SPRN_MAS1,r10
- beq+ normal_tlb_miss
+ beq+ cr1,normal_tlb_miss
/* We got a crappy address, just fault */
TLB_MISS_EPILOG_ERROR
@@ -659,10 +664,11 @@ normal_tlb_miss:
* NOTE: For 64K pages, we do things slightly differently in
* order to handle the weird page table format used by linux
*/
- ori r10,r15,0x1
+ srdi r15,r16,44
+ oris r10,r15,0x1
rldicl r14,r16,64-(PAGE_SHIFT-3),PAGE_SHIFT-3+4
- sldi r15,r10,60
- clrrdi r14,r14,3
+ sldi r15,r10,44
+ clrrdi r14,r14,19
or r10,r15,r14
ld r14,0(r10)
@@ -763,6 +769,7 @@ normal_tlb_miss_access_fault:
*/
virt_page_table_tlb_miss:
/* Are we hitting a kernel page table ? */
+ srdi r15,r16,60
andi. r10,r15,0x8
/* The cool thing now is that r10 contains 0 for user and 8 for kernel,
@@ -791,7 +798,8 @@ virt_page_table_tlb_miss:
/* Now, we need to walk the page tables. First check if we are in
* range.
*/
- rldicl. r10,r16,64-(VPTE_INDEX_SIZE+3),VPTE_INDEX_SIZE+3+4
+ rldicl r10,r16,64-(VPTE_INDEX_SIZE+3),VPTE_INDEX_SIZE+3+4
+ cmpldi r10,0x80
bne- virt_page_table_tlb_miss_fault
/* Get the PGD pointer */
@@ -910,23 +918,24 @@ virt_page_table_tlb_miss_whacko_fault:
*/
mfspr r14,SPRN_ESR
mfspr r16,SPRN_DEAR /* get faulting address */
- srdi r11,r16,60 /* get region */
- cmpldi cr0,r11,0xc /* linear mapping ? */
+ srdi r11,r16,44 /* get region */
+ xoris r11,r11,0xc
+ cmpldi cr0,r11,0 /* linear mapping ? */
beq tlb_load_linear /* yes -> go to linear map load */
+ cmpldi cr1,r11,1 /* vmalloc mapping ? */
/* We do the user/kernel test for the PID here along with the RW test
*/
- cmpldi cr0,r11,0 /* Check for user region */
+ srdi. r11,r16,60 /* Check for user region */
ld r15,PACAPGD(r13) /* Load user pgdir */
beq htw_tlb_miss
/* XXX replace the RMW cycles with immediate loads + writes */
1: mfspr r10,SPRN_MAS1
- cmpldi cr0,r11,8 /* Check for vmalloc region */
rlwinm r10,r10,0,16,1 /* Clear TID */
mtspr SPRN_MAS1,r10
ld r15,PACA_KERNELPGD(r13) /* Load kernel pgdir */
- beq+ htw_tlb_miss
+ beq+ cr1,htw_tlb_miss
/* We got a crappy address, just fault with whatever DEAR and ESR
* are here
@@ -952,19 +961,20 @@ virt_page_table_tlb_miss_whacko_fault:
*
* Faulting address is SRR0 which is already in r16
*/
- srdi r11,r16,60 /* get region */
- cmpldi cr0,r11,0xc /* linear mapping ? */
+ srdi r11,r16,44 /* get region */
+ xoris r11,r11,0xc
+ cmpldi cr0,r11,0 /* linear mapping ? */
beq tlb_load_linear /* yes -> go to linear map load */
+ cmpldi cr1,r11,1 /* vmalloc mapping ? */
/* We do the user/kernel test for the PID here along with the RW test
*/
- cmpldi cr0,r11,0 /* Check for user region */
+ srdi. r11,r16,60 /* Check for user region */
ld r15,PACAPGD(r13) /* Load user pgdir */
beq htw_tlb_miss
/* XXX replace the RMW cycles with immediate loads + writes */
1: mfspr r10,SPRN_MAS1
- cmpldi cr0,r11,8 /* Check for vmalloc region */
rlwinm r10,r10,0,16,1 /* Clear TID */
mtspr SPRN_MAS1,r10
ld r15,PACA_KERNELPGD(r13) /* Load kernel pgdir */
--
2.36.1
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