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-rw-r--r--arch/arc/mm/tlbex.S205
1 files changed, 97 insertions, 108 deletions
diff --git a/arch/arc/mm/tlbex.S b/arch/arc/mm/tlbex.S
index 5c5bb23001b..cf7d7d9ad69 100644
--- a/arch/arc/mm/tlbex.S
+++ b/arch/arc/mm/tlbex.S
@@ -44,17 +44,36 @@
#include <asm/arcregs.h>
#include <asm/cache.h>
#include <asm/processor.h>
-#if (CONFIG_ARC_MMU_VER == 1)
#include <asm/tlb-mmu1.h>
-#endif
-;--------------------------------------------------------------------------
-; scratch memory to save the registers (r0-r3) used to code TLB refill Handler
-; For details refer to comments before TLBMISS_FREEUP_REGS below
+;-----------------------------------------------------------------
+; ARC700 Exception Handling doesn't auto-switch stack and it only provides
+; ONE scratch AUX reg "ARC_REG_SCRATCH_DATA0"
+;
+; For Non-SMP, the scratch AUX reg is repurposed to cache task PGD, so a
+; "global" is used to free-up FIRST core reg to be able to code the rest of
+; exception prologue (IRQ auto-disabled on Exceptions, so it's IRQ-safe).
+; Since the Fast Path TLB Miss handler is coded with 4 regs, the remaining 3
+; need to be saved as well by extending the "global" to be 4 words. Hence
+; ".size ex_saved_reg1, 16"
+; [All of this dance is to avoid stack switching for each TLB Miss, since we
+; only need to save only a handful of regs, as opposed to complete reg file]
+;
+; For ARC700 SMP, the "global" obviously can't be used for free up the FIRST
+; core reg as it will not be SMP safe.
+; Thus scratch AUX reg is used (and no longer used to cache task PGD).
+; To save the rest of 3 regs - per cpu, the global is made "per-cpu".
+; Epilogue thus has to locate the "per-cpu" storage for regs.
+; To avoid cache line bouncing the per-cpu global is aligned/sized per
+; L1_CACHE_SHIFT, despite fundamentally needing to be 12 bytes only. Hence
+; ".size ex_saved_reg1, (CONFIG_NR_CPUS << L1_CACHE_SHIFT)"
+
+; As simple as that....
;--------------------------------------------------------------------------
+; scratch memory to save [r0-r3] used to code TLB refill Handler
ARCFP_DATA ex_saved_reg1
- .align 1 << L1_CACHE_SHIFT ; IMP: Must be Cache Line aligned
+ .align 1 << L1_CACHE_SHIFT
.type ex_saved_reg1, @object
#ifdef CONFIG_SMP
.size ex_saved_reg1, (CONFIG_NR_CPUS << L1_CACHE_SHIFT)
@@ -66,6 +85,44 @@ ex_saved_reg1:
.zero 16
#endif
+.macro TLBMISS_FREEUP_REGS
+#ifdef CONFIG_SMP
+ sr r0, [ARC_REG_SCRATCH_DATA0] ; freeup r0 to code with
+ GET_CPU_ID r0 ; get to per cpu scratch mem,
+ lsl r0, r0, L1_CACHE_SHIFT ; cache line wide per cpu
+ add r0, @ex_saved_reg1, r0
+#else
+ st r0, [@ex_saved_reg1]
+ mov_s r0, @ex_saved_reg1
+#endif
+ st_s r1, [r0, 4]
+ st_s r2, [r0, 8]
+ st_s r3, [r0, 12]
+
+ ; VERIFY if the ASID in MMU-PID Reg is same as
+ ; one in Linux data structures
+
+ tlb_paranoid_check_asm
+.endm
+
+.macro TLBMISS_RESTORE_REGS
+#ifdef CONFIG_SMP
+ GET_CPU_ID r0 ; get to per cpu scratch mem
+ lsl r0, r0, L1_CACHE_SHIFT ; each is cache line wide
+ add r0, @ex_saved_reg1, r0
+ ld_s r3, [r0,12]
+ ld_s r2, [r0, 8]
+ ld_s r1, [r0, 4]
+ lr r0, [ARC_REG_SCRATCH_DATA0]
+#else
+ mov_s r0, @ex_saved_reg1
+ ld_s r3, [r0,12]
+ ld_s r2, [r0, 8]
+ ld_s r1, [r0, 4]
+ ld_s r0, [r0]
+#endif
+.endm
+
;============================================================================
; Troubleshooting Stuff
;============================================================================
@@ -76,34 +133,35 @@ ex_saved_reg1:
; In bizzare scenrios SW and HW ASID can get out-of-sync which is trouble.
; So we try to detect this in TLB Mis shandler
-
-.macro DBG_ASID_MISMATCH
+.macro tlb_paranoid_check_asm
#ifdef CONFIG_ARC_DBG_TLB_PARANOIA
- ; make sure h/w ASID is same as s/w ASID
-
GET_CURR_TASK_ON_CPU r3
ld r0, [r3, TASK_ACT_MM]
ld r0, [r0, MM_CTXT+MM_CTXT_ASID]
+ breq r0, 0, 55f ; Error if no ASID allocated
lr r1, [ARC_REG_PID]
and r1, r1, 0xFF
- breq r1, r0, 5f
+ and r2, r0, 0xFF ; MMU PID bits only for comparison
+ breq r1, r2, 5f
+
+55:
; Error if H/w and S/w ASID don't match, but NOT if in kernel mode
- lr r0, [erstatus]
- bbit0 r0, STATUS_U_BIT, 5f
+ lr r2, [erstatus]
+ bbit0 r2, STATUS_U_BIT, 5f
; We sure are in troubled waters, Flag the error, but to do so
; need to switch to kernel mode stack to call error routine
GET_TSK_STACK_BASE r3, sp
; Call printk to shoutout aloud
- mov r0, 1
+ mov r2, 1
j print_asid_mismatch
-5: ; ASIDs match so proceed normally
+5: ; ASIDs match so proceed normally
nop
#endif
@@ -161,13 +219,17 @@ ex_saved_reg1:
; IN: r0 = PTE, r1 = ptr to PTE
.macro CONV_PTE_TO_TLB
- and r3, r0, PTE_BITS_IN_PD1 ; Extract permission flags+PFN from PTE
- sr r3, [ARC_REG_TLBPD1] ; these go in PD1
+ and r3, r0, PTE_BITS_RWX ; r w x
+ lsl r2, r3, 3 ; r w x 0 0 0
+ and.f 0, r0, _PAGE_GLOBAL
+ or.z r2, r2, r3 ; r w x r w x
+
+ and r3, r0, PTE_BITS_NON_RWX_IN_PD1 ; Extract PFN+cache bits from PTE
+ or r3, r3, r2
+
+ sr r3, [ARC_REG_TLBPD1] ; these go in PD1
and r2, r0, PTE_BITS_IN_PD0 ; Extract other PTE flags: (V)alid, (G)lb
-#if (CONFIG_ARC_MMU_VER <= 2) /* Neednot be done with v3 onwards */
- lsr r2, r2 ; shift PTE flags to match layout in PD0
-#endif
lr r3,[ARC_REG_TLBPD0] ; MMU prepares PD0 with vaddr and asid
@@ -191,68 +253,6 @@ ex_saved_reg1:
#endif
.endm
-;-----------------------------------------------------------------
-; ARC700 Exception Handling doesn't auto-switch stack and it only provides
-; ONE scratch AUX reg "ARC_REG_SCRATCH_DATA0"
-;
-; For Non-SMP, the scratch AUX reg is repurposed to cache task PGD, so a
-; "global" is used to free-up FIRST core reg to be able to code the rest of
-; exception prologue (IRQ auto-disabled on Exceptions, so it's IRQ-safe).
-; Since the Fast Path TLB Miss handler is coded with 4 regs, the remaining 3
-; need to be saved as well by extending the "global" to be 4 words. Hence
-; ".size ex_saved_reg1, 16"
-; [All of this dance is to avoid stack switching for each TLB Miss, since we
-; only need to save only a handful of regs, as opposed to complete reg file]
-;
-; For ARC700 SMP, the "global" obviously can't be used for free up the FIRST
-; core reg as it will not be SMP safe.
-; Thus scratch AUX reg is used (and no longer used to cache task PGD).
-; To save the rest of 3 regs - per cpu, the global is made "per-cpu".
-; Epilogue thus has to locate the "per-cpu" storage for regs.
-; To avoid cache line bouncing the per-cpu global is aligned/sized per
-; L1_CACHE_SHIFT, despite fundamentally needing to be 12 bytes only. Hence
-; ".size ex_saved_reg1, (CONFIG_NR_CPUS << L1_CACHE_SHIFT)"
-
-; As simple as that....
-
-.macro TLBMISS_FREEUP_REGS
-#ifdef CONFIG_SMP
- sr r0, [ARC_REG_SCRATCH_DATA0] ; freeup r0 to code with
- GET_CPU_ID r0 ; get to per cpu scratch mem,
- lsl r0, r0, L1_CACHE_SHIFT ; cache line wide per cpu
- add r0, @ex_saved_reg1, r0
-#else
- st r0, [@ex_saved_reg1]
- mov_s r0, @ex_saved_reg1
-#endif
- st_s r1, [r0, 4]
- st_s r2, [r0, 8]
- st_s r3, [r0, 12]
-
- ; VERIFY if the ASID in MMU-PID Reg is same as
- ; one in Linux data structures
-
- DBG_ASID_MISMATCH
-.endm
-
-;-----------------------------------------------------------------
-.macro TLBMISS_RESTORE_REGS
-#ifdef CONFIG_SMP
- GET_CPU_ID r0 ; get to per cpu scratch mem
- lsl r0, r0, L1_CACHE_SHIFT ; each is cache line wide
- add r0, @ex_saved_reg1, r0
- ld_s r3, [r0,12]
- ld_s r2, [r0, 8]
- ld_s r1, [r0, 4]
- lr r0, [ARC_REG_SCRATCH_DATA0]
-#else
- mov_s r0, @ex_saved_reg1
- ld_s r3, [r0,12]
- ld_s r2, [r0, 8]
- ld_s r1, [r0, 4]
- ld_s r0, [r0]
-#endif
-.endm
ARCFP_CODE ;Fast Path Code, candidate for ICCM
@@ -277,8 +277,8 @@ ARC_ENTRY EV_TLBMissI
;----------------------------------------------------------------
; VERIFY_PTE: Check if PTE permissions approp for executing code
cmp_s r2, VMALLOC_START
- mov.lo r2, (_PAGE_PRESENT | _PAGE_U_EXECUTE)
- mov.hs r2, (_PAGE_PRESENT | _PAGE_K_EXECUTE)
+ mov_s r2, (_PAGE_PRESENT | _PAGE_EXECUTE)
+ or.hs r2, r2, _PAGE_GLOBAL
and r3, r0, r2 ; Mask out NON Flag bits from PTE
xor.f r3, r3, r2 ; check ( ( pte & flags_test ) == flags_test )
@@ -317,26 +317,21 @@ ARC_ENTRY EV_TLBMissD
;----------------------------------------------------------------
; VERIFY_PTE: Chk if PTE permissions approp for data access (R/W/R+W)
- mov_s r2, 0
+ cmp_s r2, VMALLOC_START
+ mov_s r2, _PAGE_PRESENT ; common bit for K/U PTE
+ or.hs r2, r2, _PAGE_GLOBAL ; kernel PTE only
+
+ ; Linux PTE [RWX] bits are semantically overloaded:
+ ; -If PAGE_GLOBAL set, they refer to kernel-only flags (vmalloc)
+ ; -Otherwise they are user-mode permissions, and those are exactly
+ ; same for kernel mode as well (e.g. copy_(to|from)_user)
+
lr r3, [ecr]
btst_s r3, ECR_C_BIT_DTLB_LD_MISS ; Read Access
- or.nz r2, r2, _PAGE_U_READ ; chk for Read flag in PTE
+ or.nz r2, r2, _PAGE_READ ; chk for Read flag in PTE
btst_s r3, ECR_C_BIT_DTLB_ST_MISS ; Write Access
- or.nz r2, r2, _PAGE_U_WRITE ; chk for Write flag in PTE
- ; Above laddering takes care of XCHG access
- ; which is both Read and Write
-
- ; If kernel mode access, ; make _PAGE_xx flags as _PAGE_K_xx
- ; For copy_(to|from)_user, despite exception taken in kernel mode,
- ; this code is not hit, because EFA would still be the user mode
- ; address (EFA < 0x6000_0000).
- ; This code is for legit kernel mode faults, vmalloc specifically
- ; (EFA: 0x7000_0000 to 0x7FFF_FFFF)
-
- lr r3, [efa]
- cmp r3, VMALLOC_START - 1 ; If kernel mode access
- asl.hi r2, r2, 3 ; make _PAGE_xx flags as _PAGE_K_xx
- or r2, r2, _PAGE_PRESENT ; Common flag for K/U mode
+ or.nz r2, r2, _PAGE_WRITE ; chk for Write flag in PTE
+ ; Above laddering takes care of XCHG access (both R and W)
; By now, r2 setup with all the Flags we need to check in PTE
and r3, r0, r2 ; Mask out NON Flag bits from PTE
@@ -371,13 +366,7 @@ do_slow_path_pf:
; Slow path TLB Miss handled as a regular ARC Exception
; (stack switching / save the complete reg-file).
- ; That requires freeing up r9
- EXCPN_PROLOG_FREEUP_REG r9
-
- lr r9, [erstatus]
-
- SWITCH_TO_KERNEL_STK
- SAVE_ALL_SYS
+ EXCEPTION_PROLOGUE
; ------- setup args for Linux Page fault Hanlder ---------
mov_s r0, sp
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2024-12-18 03:15:20 +0000