[PATCH v4 16/16] powerpc/32s: Activate CONFIG_VMAP_STACK

From: Christophe Leroy
Date: Tue Nov 26 2019 - 07:36:39 EST

A few changes to retrieve DAR and DSISR from struct regs
instead of retrieving them directly, as they may have
changed due to a TLB miss.

Also modifies hash_page() and friends to work with virtual
data addresses instead of physical ones. Same on load_up_fpu()
and load_up_altivec().

Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxx>
---
arch/powerpc/kernel/entry_32.S | 4 +++
arch/powerpc/kernel/fpu.S | 3 +++
arch/powerpc/kernel/head_32.S | 19 +++++++++++---
arch/powerpc/kernel/head_32.h | 4 ++-
arch/powerpc/kernel/vector.S | 3 +++
arch/powerpc/mm/book3s32/hash_low.S | 46 +++++++++++++++++++++-------------
arch/powerpc/mm/book3s32/mmu.c | 9 +++++--
arch/powerpc/platforms/Kconfig.cputype | 2 ++
8 files changed, 67 insertions(+), 23 deletions(-)

diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S
index 00fcf954e742..1d3b152ee54f 100644
--- a/arch/powerpc/kernel/entry_32.S
+++ b/arch/powerpc/kernel/entry_32.S
@@ -1365,7 +1365,11 @@ _GLOBAL(enter_rtas)
lis r6,1f@ha /* physical return address for rtas */
addi r6,r6,1f@l
tophys(r6,r6)
+#ifdef CONFIG_VMAP_STACK
+ mr r7, r1
+#else
tophys(r7,r1)
+#endif
lwz r8,RTASENTRY(r4)
lwz r4,RTASBASE(r4)
mfmsr r9
diff --git a/arch/powerpc/kernel/fpu.S b/arch/powerpc/kernel/fpu.S
index 0bb991ddd264..3235a8da6af7 100644
--- a/arch/powerpc/kernel/fpu.S
+++ b/arch/powerpc/kernel/fpu.S
@@ -94,6 +94,9 @@ END_FTR_SECTION_IFSET(CPU_FTR_VSX)
/* enable use of FP after return */
#ifdef CONFIG_PPC32
mfspr r5,SPRN_SPRG_THREAD /* current task's THREAD (phys) */
+#ifdef CONFIG_VMAP_STACK
+ tovirt(r5, r5)
+#endif
lwz r4,THREAD_FPEXC_MODE(r5)
ori r9,r9,MSR_FP /* enable FP for current */
or r9,r9,r4
diff --git a/arch/powerpc/kernel/head_32.S b/arch/powerpc/kernel/head_32.S
index 90ef355e958b..28391a408a22 100644
--- a/arch/powerpc/kernel/head_32.S
+++ b/arch/powerpc/kernel/head_32.S
@@ -272,14 +272,22 @@ __secondary_hold_acknowledge:
*/
. = 0x200
DO_KVM 0x200
+MachineCheck:
EXCEPTION_PROLOG_0
+#ifdef CONFIG_VMAP_STACK
+ li r11, MSR_KERNEL & ~(MSR_IR | MSR_RI) /* can take DTLB miss */
+ mtmsr r11
+#endif
#ifdef CONFIG_PPC_CHRP
mfspr r11, SPRN_SPRG_THREAD
+#ifdef CONFIG_VMAP_STACK
+ tovirt(r11, r11)
+#endif
lwz r11, RTAS_SP(r11)
cmpwi cr1, r11, 0
bne cr1, 7f
#endif /* CONFIG_PPC_CHRP */
- EXCEPTION_PROLOG_1
+ EXCEPTION_PROLOG_1 rtas
7: EXCEPTION_PROLOG_2
addi r3,r1,STACK_FRAME_OVERHEAD
#ifdef CONFIG_PPC_CHRP
@@ -294,7 +302,7 @@ __secondary_hold_acknowledge:
. = 0x300
DO_KVM 0x300
DataAccess:
- EXCEPTION_PROLOG
+ EXCEPTION_PROLOG dar
get_and_save_dar_dsisr_on_stack r4, r5, r11
BEGIN_MMU_FTR_SECTION
#ifdef CONFIG_PPC_KUAP
@@ -334,7 +342,7 @@ END_MMU_FTR_SECTION_IFSET(MMU_FTR_HPTE_TABLE)
. = 0x600
DO_KVM 0x600
Alignment:
- EXCEPTION_PROLOG
+ EXCEPTION_PROLOG dar
save_dar_dsisr_on_stack r4, r5, r11
addi r3,r1,STACK_FRAME_OVERHEAD
EXC_XFER_STD(0x600, alignment_exception)
@@ -645,6 +653,11 @@ handle_page_fault_tramp_1:
handle_page_fault_tramp_2:
EXC_XFER_LITE(0x300, handle_page_fault)

+#ifdef CONFIG_VMAP_STACK
+stack_ovf_trampoline:
+ b stack_ovf
+#endif
+
AltiVecUnavailable:
EXCEPTION_PROLOG
#ifdef CONFIG_ALTIVEC
diff --git a/arch/powerpc/kernel/head_32.h b/arch/powerpc/kernel/head_32.h
index 283d4298d555..ae2c8e07e1d5 100644
--- a/arch/powerpc/kernel/head_32.h
+++ b/arch/powerpc/kernel/head_32.h
@@ -38,10 +38,12 @@
andi. r11, r11, MSR_PR
.endm

-.macro EXCEPTION_PROLOG_1
+.macro EXCEPTION_PROLOG_1 rtas
#ifdef CONFIG_VMAP_STACK
+ .ifb \rtas
li r11, MSR_KERNEL & ~(MSR_IR | MSR_RI) /* can take DTLB miss */
mtmsr r11
+ .endif
subi r11, r1, INT_FRAME_SIZE /* use r1 if kernel */
#else
tophys(r11,r1) /* use tophys(r1) if kernel */
diff --git a/arch/powerpc/kernel/vector.S b/arch/powerpc/kernel/vector.S
index 8eb867dbad5f..25c14a0981bf 100644
--- a/arch/powerpc/kernel/vector.S
+++ b/arch/powerpc/kernel/vector.S
@@ -67,6 +67,9 @@ _GLOBAL(load_up_altivec)
#ifdef CONFIG_PPC32
mfspr r5,SPRN_SPRG_THREAD /* current task's THREAD (phys) */
oris r9,r9,MSR_VEC@h
+#ifdef CONFIG_VMAP_STACK
+ tovirt(r5, r5)
+#endif
#else
ld r4,PACACURRENT(r13)
addi r5,r4,THREAD /* Get THREAD */
diff --git a/arch/powerpc/mm/book3s32/hash_low.S b/arch/powerpc/mm/book3s32/hash_low.S
index 8bbbd9775c8a..c11b0a005196 100644
--- a/arch/powerpc/mm/book3s32/hash_low.S
+++ b/arch/powerpc/mm/book3s32/hash_low.S
@@ -25,6 +25,12 @@
#include <asm/feature-fixups.h>
#include <asm/code-patching-asm.h>

+#ifdef CONFIG_VMAP_STACK
+#define ADDR_OFFSET 0
+#else
+#define ADDR_OFFSET PAGE_OFFSET
+#endif
+
#ifdef CONFIG_SMP
.section .bss
.align 2
@@ -47,8 +53,8 @@ mmu_hash_lock:
.text
_GLOBAL(hash_page)
#ifdef CONFIG_SMP
- lis r8, (mmu_hash_lock - PAGE_OFFSET)@h
- ori r8, r8, (mmu_hash_lock - PAGE_OFFSET)@l
+ lis r8, (mmu_hash_lock - ADDR_OFFSET)@h
+ ori r8, r8, (mmu_hash_lock - ADDR_OFFSET)@l
lis r0,0x0fff
b 10f
11: lwz r6,0(r8)
@@ -66,9 +72,12 @@ _GLOBAL(hash_page)
cmplw 0,r4,r0
ori r3,r3,_PAGE_USER|_PAGE_PRESENT /* test low addresses as user */
mfspr r5, SPRN_SPRG_PGDIR /* phys page-table root */
+#ifdef CONFIG_VMAP_STACK
+ tovirt(r5, r5)
+#endif
blt+ 112f /* assume user more likely */
- lis r5, (swapper_pg_dir - PAGE_OFFSET)@ha /* if kernel address, use */
- addi r5 ,r5 ,(swapper_pg_dir - PAGE_OFFSET)@l /* kernel page table */
+ lis r5, (swapper_pg_dir - ADDR_OFFSET)@ha /* if kernel address, use */
+ addi r5 ,r5 ,(swapper_pg_dir - ADDR_OFFSET)@l /* kernel page table */
rlwimi r3,r9,32-12,29,29 /* MSR_PR -> _PAGE_USER */
112:
#ifndef CONFIG_PTE_64BIT
@@ -80,6 +89,9 @@ _GLOBAL(hash_page)
lwzx r8,r8,r5 /* Get L1 entry */
rlwinm. r8,r8,0,0,20 /* extract pt base address */
#endif
+#ifdef CONFIG_VMAP_STACK
+ tovirt(r8, r8)
+#endif
#ifdef CONFIG_SMP
beq- hash_page_out /* return if no mapping */
#else
@@ -137,9 +149,9 @@ retry:

#ifdef CONFIG_SMP
eieio
- lis r8, (mmu_hash_lock - PAGE_OFFSET)@ha
+ lis r8, (mmu_hash_lock - ADDR_OFFSET)@ha
li r0,0
- stw r0, (mmu_hash_lock - PAGE_OFFSET)@l(r8)
+ stw r0, (mmu_hash_lock - ADDR_OFFSET)@l(r8)
#endif

/* Return from the exception */
@@ -152,9 +164,9 @@ retry:
#ifdef CONFIG_SMP
hash_page_out:
eieio
- lis r8, (mmu_hash_lock - PAGE_OFFSET)@ha
+ lis r8, (mmu_hash_lock - ADDR_OFFSET)@ha
li r0,0
- stw r0, (mmu_hash_lock - PAGE_OFFSET)@l(r8)
+ stw r0, (mmu_hash_lock - ADDR_OFFSET)@l(r8)
blr
#endif /* CONFIG_SMP */

@@ -329,7 +341,7 @@ END_FTR_SECTION_IFCLR(CPU_FTR_NEED_COHERENT)
patch_site 1f, patch__hash_page_A1
patch_site 2f, patch__hash_page_A2
/* Get the address of the primary PTE group in the hash table (r3) */
-0: lis r0, (Hash_base - PAGE_OFFSET)@h /* base address of hash table */
+0: lis r0, (Hash_base - ADDR_OFFSET)@h /* base address of hash table */
1: rlwimi r0,r3,LG_PTEG_SIZE,HASH_LEFT,HASH_RIGHT /* VSID -> hash */
2: rlwinm r3,r4,20+LG_PTEG_SIZE,HASH_LEFT,HASH_RIGHT /* PI -> hash */
xor r3,r3,r0 /* make primary hash */
@@ -343,10 +355,10 @@ END_FTR_SECTION_IFCLR(CPU_FTR_NEED_COHERENT)
beq+ 10f /* no PTE: go look for an empty slot */
tlbie r4

- lis r4, (htab_hash_searches - PAGE_OFFSET)@ha
- lwz r6, (htab_hash_searches - PAGE_OFFSET)@l(r4)
+ lis r4, (htab_hash_searches - ADDR_OFFSET)@ha
+ lwz r6, (htab_hash_searches - ADDR_OFFSET)@l(r4)
addi r6,r6,1 /* count how many searches we do */
- stw r6, (htab_hash_searches - PAGE_OFFSET)@l(r4)
+ stw r6, (htab_hash_searches - ADDR_OFFSET)@l(r4)

/* Search the primary PTEG for a PTE whose 1st (d)word matches r5 */
mtctr r0
@@ -378,10 +390,10 @@ END_FTR_SECTION_IFCLR(CPU_FTR_NEED_COHERENT)
beq+ found_empty

/* update counter of times that the primary PTEG is full */
- lis r4, (primary_pteg_full - PAGE_OFFSET)@ha
- lwz r6, (primary_pteg_full - PAGE_OFFSET)@l(r4)
+ lis r4, (primary_pteg_full - ADDR_OFFSET)@ha
+ lwz r6, (primary_pteg_full - ADDR_OFFSET)@l(r4)
addi r6,r6,1
- stw r6, (primary_pteg_full - PAGE_OFFSET)@l(r4)
+ stw r6, (primary_pteg_full - ADDR_OFFSET)@l(r4)

patch_site 0f, patch__hash_page_C
/* Search the secondary PTEG for an empty slot */
@@ -415,8 +427,8 @@ END_FTR_SECTION_IFCLR(CPU_FTR_NEED_COHERENT)
* lockup here but that shouldn't happen
*/

-1: lis r4, (next_slot - PAGE_OFFSET)@ha /* get next evict slot */
- lwz r6, (next_slot - PAGE_OFFSET)@l(r4)
+1: lis r4, (next_slot - ADDR_OFFSET)@ha /* get next evict slot */
+ lwz r6, (next_slot - ADDR_OFFSET)@l(r4)
addi r6,r6,HPTE_SIZE /* search for candidate */
andi. r6,r6,7*HPTE_SIZE
stw r6,next_slot@l(r4)
diff --git a/arch/powerpc/mm/book3s32/mmu.c b/arch/powerpc/mm/book3s32/mmu.c
index 69b2419accef..0a1c65a2c565 100644
--- a/arch/powerpc/mm/book3s32/mmu.c
+++ b/arch/powerpc/mm/book3s32/mmu.c
@@ -413,6 +413,7 @@ void __init MMU_init_hw(void)
void __init MMU_init_hw_patch(void)
{
unsigned int hmask = Hash_mask >> (16 - LG_HPTEG_SIZE);
+ unsigned int hash;

if (ppc_md.progress)
ppc_md.progress("hash:patch", 0x345);
@@ -424,8 +425,12 @@ void __init MMU_init_hw_patch(void)
/*
* Patch up the instructions in hashtable.S:create_hpte
*/
- modify_instruction_site(&patch__hash_page_A0, 0xffff,
- ((unsigned int)Hash - PAGE_OFFSET) >> 16);
+ if (IS_ENABLED(CONFIG_VMAP_STACK))
+ hash = (unsigned int)Hash;
+ else
+ hash = (unsigned int)Hash - PAGE_OFFSET;
+
+ modify_instruction_site(&patch__hash_page_A0, 0xffff, hash >> 16);
modify_instruction_site(&patch__hash_page_A1, 0x7c0, hash_mb << 6);
modify_instruction_site(&patch__hash_page_A2, 0x7c0, hash_mb2 << 6);
modify_instruction_site(&patch__hash_page_B, 0xffff, hmask);
diff --git a/arch/powerpc/platforms/Kconfig.cputype b/arch/powerpc/platforms/Kconfig.cputype
index f0583251e9a3..c5dbc2f9449d 100644
--- a/arch/powerpc/platforms/Kconfig.cputype
+++ b/arch/powerpc/platforms/Kconfig.cputype
@@ -31,12 +31,14 @@ config PPC_BOOK3S_6xx
select PPC_HAVE_PMU_SUPPORT
select PPC_HAVE_KUEP
select PPC_HAVE_KUAP
+ select HAVE_ARCH_VMAP_STACK

config PPC_BOOK3S_601
bool "PowerPC 601"
select PPC_BOOK3S_32
select PPC_FPU
select PPC_HAVE_KUAP
+ select HAVE_ARCH_VMAP_STACK

config PPC_85xx
bool "Freescale 85xx"
--
2.13.3