[PATCH 10/29] csky: Remove prologue of page fault handler in entry.S
From: guoren
Date: Thu Jan 21 2021 - 02:52:05 EST
From: Guo Ren <guoren@xxxxxxxxxxxxxxxxx>
There is a prologue on page fault handler which marking pages dirty
and/or accessed in page attributes, but all of these have been
handled in handle_pte_fault.
- Add flush_tlb_one in vmalloc page fault instead of prologue.
- Using cmxchg_fixup C codes in do_page_fault instead of ASM one.
Signed-off-by: Guo Ren <guoren@xxxxxxxxxxxxxxxxx>
---
arch/csky/kernel/atomic.S | 20 +-------
arch/csky/kernel/entry.S | 104 +-------------------------------------
arch/csky/kernel/traps.c | 10 ++--
arch/csky/mm/fault.c | 45 +++++++++++++++--
4 files changed, 48 insertions(+), 131 deletions(-)
diff --git a/arch/csky/kernel/atomic.S b/arch/csky/kernel/atomic.S
index f03db1d8d060..e73e548f7855 100644
--- a/arch/csky/kernel/atomic.S
+++ b/arch/csky/kernel/atomic.S
@@ -40,11 +40,11 @@ ENTRY(csky_cmpxchg)
2:
sync.is
#else
-1:
+GLOBAL(csky_cmpxchg_ldw)
ldw a3, (a2)
cmpne a0, a3
bt16 3f
-2:
+GLOBAL(csky_cmpxchg_stw)
stw a1, (a2)
3:
#endif
@@ -59,19 +59,3 @@ ENTRY(csky_cmpxchg)
KSPTOUSP
rte
END(csky_cmpxchg)
-
-#ifndef CONFIG_CPU_HAS_LDSTEX
-/*
- * Called from tlbmodified exception
- */
-ENTRY(csky_cmpxchg_fixup)
- mfcr a0, epc
- lrw a1, 2b
- cmpne a1, a0
- bt 1f
- subi a1, (2b - 1b)
- stw a1, (sp, LSAVE_PC)
-1:
- rts
-END(csky_cmpxchg_fixup)
-#endif
diff --git a/arch/csky/kernel/entry.S b/arch/csky/kernel/entry.S
index d5f6d04b21a8..185fea477a8d 100644
--- a/arch/csky/kernel/entry.S
+++ b/arch/csky/kernel/entry.S
@@ -13,10 +13,6 @@
#include <asm/page.h>
#include <asm/thread_info.h>
-#define PTE_INDX_MSK 0xffc
-#define PTE_INDX_SHIFT 10
-#define _PGDIR_SHIFT 22
-
.macro zero_fp
#ifdef CONFIG_STACKTRACE
movi r8, 0
@@ -41,111 +37,15 @@
#endif
.endm
-.macro tlbop_begin name, val0, val1, val2
-ENTRY(csky_\name)
- mtcr a3, ss2
- mtcr r6, ss3
- mtcr a2, ss4
-
- RD_PGDR r6
- RD_MEH a3
- WR_MEH a3
-#ifdef CONFIG_CPU_HAS_TLBI
- tlbi.vaas a3
- sync.is
-
- btsti a3, 31
- bf 1f
- RD_PGDR_K r6
-1:
-#else
- bgeni a2, 31
- WR_MCIR a2
- bgeni a2, 25
- WR_MCIR a2
-#endif
- bclri r6, 0
- lrw a2, PAGE_OFFSET
- add r6, a2
- lrw a2, va_pa_offset
- ld.w a2, (a2, 0)
- subu r6, a2
-
- mov a2, a3
- lsri a2, _PGDIR_SHIFT
- lsli a2, 2
- addu r6, a2
- ldw r6, (r6)
-
- lrw a2, PAGE_OFFSET
- add r6, a2
- lrw a2, va_pa_offset
- ld.w a2, (a2, 0)
- subu r6, a2
-
- lsri a3, PTE_INDX_SHIFT
- lrw a2, PTE_INDX_MSK
- and a3, a2
- addu r6, a3
- ldw a3, (r6)
-
- movi a2, (_PAGE_PRESENT | \val0)
- and a3, a2
- cmpne a3, a2
- bt \name
-
- /* First read/write the page, just update the flags */
- ldw a3, (r6)
- bgeni a2, PAGE_VALID_BIT
- bseti a2, PAGE_ACCESSED_BIT
- bseti a2, \val1
- bseti a2, \val2
- or a3, a2
- stw a3, (r6)
-
- /* Some cpu tlb-hardrefill bypass the cache */
-#ifdef CONFIG_CPU_NEED_TLBSYNC
- movi a2, 0x22
- bseti a2, 6
- mtcr r6, cr22
- mtcr a2, cr17
- sync
-#endif
-
- mfcr a3, ss2
- mfcr r6, ss3
- mfcr a2, ss4
- rte
-\name:
- mfcr a3, ss2
- mfcr r6, ss3
- mfcr a2, ss4
+.text
+ENTRY(csky_pagefault)
SAVE_ALL 0
-.endm
-.macro tlbop_end is_write
zero_fp
context_tracking
- RD_MEH a2
psrset ee, ie
mov a0, sp
- movi a1, \is_write
jbsr do_page_fault
jmpi ret_from_exception
-.endm
-
-.text
-
-tlbop_begin tlbinvalidl, _PAGE_READ, PAGE_VALID_BIT, PAGE_ACCESSED_BIT
-tlbop_end 0
-
-tlbop_begin tlbinvalids, _PAGE_WRITE, PAGE_DIRTY_BIT, PAGE_MODIFIED_BIT
-tlbop_end 1
-
-tlbop_begin tlbmodified, _PAGE_WRITE, PAGE_DIRTY_BIT, PAGE_MODIFIED_BIT
-#ifndef CONFIG_CPU_HAS_LDSTEX
-jbsr csky_cmpxchg_fixup
-#endif
-tlbop_end 1
ENTRY(csky_systemcall)
SAVE_ALL TRAP0_SIZE
diff --git a/arch/csky/kernel/traps.c b/arch/csky/kernel/traps.c
index 959a917c989d..e5fbf8653a21 100644
--- a/arch/csky/kernel/traps.c
+++ b/arch/csky/kernel/traps.c
@@ -39,9 +39,7 @@ asmlinkage void csky_cmpxchg(void);
asmlinkage void csky_get_tls(void);
asmlinkage void csky_irq(void);
-asmlinkage void csky_tlbinvalidl(void);
-asmlinkage void csky_tlbinvalids(void);
-asmlinkage void csky_tlbmodified(void);
+asmlinkage void csky_pagefault(void);
/* Defined in head.S */
asmlinkage void _start_smp_secondary(void);
@@ -66,9 +64,9 @@ void __init trap_init(void)
VEC_INIT(VEC_TRAP3, csky_get_tls);
/* setup MMU TLB exception */
- VEC_INIT(VEC_TLBINVALIDL, csky_tlbinvalidl);
- VEC_INIT(VEC_TLBINVALIDS, csky_tlbinvalids);
- VEC_INIT(VEC_TLBMODIFIED, csky_tlbmodified);
+ VEC_INIT(VEC_TLBINVALIDL, csky_pagefault);
+ VEC_INIT(VEC_TLBINVALIDS, csky_pagefault);
+ VEC_INIT(VEC_TLBMODIFIED, csky_pagefault);
#ifdef CONFIG_CPU_HAS_FPU
init_fpu();
diff --git a/arch/csky/mm/fault.c b/arch/csky/mm/fault.c
index 94eac13b9c97..e888acf1c403 100644
--- a/arch/csky/mm/fault.c
+++ b/arch/csky/mm/fault.c
@@ -39,20 +39,52 @@ int fixup_exception(struct pt_regs *regs)
return 0;
}
+static inline bool is_write(struct pt_regs *regs)
+{
+ switch (trap_no(regs)) {
+ case VEC_TLBINVALIDS:
+ return true;
+ case VEC_TLBMODIFIED:
+ return true;
+ }
+
+ return false;
+}
+
+#ifdef CONFIG_CPU_HAS_LDSTEX
+static inline void csky_cmpxchg_fixup(struct pt_regs *regs)
+{
+ return;
+}
+#else
+extern unsigned long csky_cmpxchg_ldw;
+extern unsigned long csky_cmpxchg_stw;
+static inline void csky_cmpxchg_fixup(struct pt_regs *regs)
+{
+ if (trap_no(regs) != VEC_TLBMODIFIED)
+ return;
+
+ if (instruction_pointer(regs) == csky_cmpxchg_stw)
+ instruction_pointer_set(regs, csky_cmpxchg_ldw);
+ return;
+}
+#endif
+
/*
* This routine handles page faults. It determines the address,
* and the problem, and then passes it off to one of the appropriate
* routines.
*/
-asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long write,
- unsigned long mmu_meh)
+asmlinkage void do_page_fault(struct pt_regs *regs)
{
struct vm_area_struct *vma = NULL;
struct task_struct *tsk = current;
struct mm_struct *mm = tsk->mm;
int si_code;
int fault;
- unsigned long address = mmu_meh & PAGE_MASK;
+ unsigned long address = read_mmu_entryhi() & PAGE_MASK;
+
+ csky_cmpxchg_fixup(regs);
if (kprobe_page_fault(regs, tsk->thread.trap_no))
return;
@@ -104,6 +136,9 @@ asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long write,
pte_k = pte_offset_kernel(pmd_k, address);
if (!pte_present(*pte_k))
goto no_context;
+
+ flush_tlb_one(address);
+
return;
}
@@ -132,7 +167,7 @@ asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long write,
good_area:
si_code = SEGV_ACCERR;
- if (write) {
+ if (is_write(regs)) {
if (!(vma->vm_flags & VM_WRITE))
goto bad_area;
} else {
@@ -145,7 +180,7 @@ asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long write,
* make sure we exit gracefully rather than endlessly redo
* the fault.
*/
- fault = handle_mm_fault(vma, address, write ? FAULT_FLAG_WRITE : 0,
+ fault = handle_mm_fault(vma, address, is_write(regs) ? FAULT_FLAG_WRITE : 0,
regs);
if (unlikely(fault & VM_FAULT_ERROR)) {
if (fault & VM_FAULT_OOM)
--
2.17.1