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Subject[PATCH 17/29] microblaze_mmu_v2: Update exception handling - MMU exception
Date
Signed-off-by: Michal Simek <monstr@monstr.eu>
---
arch/microblaze/kernel/hw_exception_handler.S | 746 ++++++++++++++++++++++++-
1 files changed, 739 insertions(+), 7 deletions(-)

diff --git a/arch/microblaze/kernel/hw_exception_handler.S b/arch/microblaze/kernel/hw_exception_handler.S
index cf9486d..9d591cd 100644
--- a/arch/microblaze/kernel/hw_exception_handler.S
+++ b/arch/microblaze/kernel/hw_exception_handler.S
@@ -53,6 +53,12 @@
* - Illegal instruction opcode
* - Divide-by-zero
*
+ * - Privileged instruction exception (MMU)
+ * - Data storage exception (MMU)
+ * - Instruction storage exception (MMU)
+ * - Data TLB miss exception (MMU)
+ * - Instruction TLB miss exception (MMU)
+ *
* Note we disable interrupts during exception handling, otherwise we will
* possibly get multiple re-entrancy if interrupt handles themselves cause
* exceptions. JW
@@ -71,9 +77,24 @@
#include <asm/asm-offsets.h>

/* Helpful Macros */
+#ifndef CONFIG_MMU
#define EX_HANDLER_STACK_SIZ (4*19)
+#endif
#define NUM_TO_REG(num) r ## num

+#ifdef CONFIG_MMU
+/* FIXME you can't change first load of MSR because there is
+ * hardcoded jump bri 4 */
+ #define RESTORE_STATE \
+ lwi r3, r1, PT_R3; \
+ lwi r4, r1, PT_R4; \
+ lwi r5, r1, PT_R5; \
+ lwi r6, r1, PT_R6; \
+ lwi r11, r1, PT_R11; \
+ lwi r31, r1, PT_R31; \
+ lwi r1, r0, TOPHYS(r0_ram + 0);
+#endif /* CONFIG_MMU */
+
#define LWREG_NOP \
bri ex_handler_unhandled; \
nop;
@@ -106,6 +127,54 @@
or r3, r0, NUM_TO_REG (regnum); \
bri ex_sw_tail;

+#ifdef CONFIG_MMU
+ #define R3_TO_LWREG_VM_V(regnum) \
+ brid ex_lw_end_vm; \
+ swi r3, r7, 4 * regnum;
+
+ #define R3_TO_LWREG_VM(regnum) \
+ brid ex_lw_end_vm; \
+ or NUM_TO_REG (regnum), r0, r3;
+
+ #define SWREG_TO_R3_VM_V(regnum) \
+ brid ex_sw_tail_vm; \
+ lwi r3, r7, 4 * regnum;
+
+ #define SWREG_TO_R3_VM(regnum) \
+ brid ex_sw_tail_vm; \
+ or r3, r0, NUM_TO_REG (regnum);
+
+ /* Shift right instruction depending on available configuration */
+ #if CONFIG_XILINX_MICROBLAZE0_USE_BARREL > 0
+ #define BSRLI(rD, rA, imm) \
+ bsrli rD, rA, imm
+ #elif CONFIG_XILINX_MICROBLAZE0_USE_DIV > 0
+ #define BSRLI(rD, rA, imm) \
+ ori rD, r0, (1 << imm); \
+ idivu rD, rD, rA
+ #else
+ #define BSRLI(rD, rA, imm) BSRLI ## imm (rD, rA)
+ /* Only the used shift constants defined here - add more if needed */
+ #define BSRLI2(rD, rA) \
+ srl rD, rA; /* << 1 */ \
+ srl rD, rD; /* << 2 */
+ #define BSRLI10(rD, rA) \
+ srl rD, rA; /* << 1 */ \
+ srl rD, rD; /* << 2 */ \
+ srl rD, rD; /* << 3 */ \
+ srl rD, rD; /* << 4 */ \
+ srl rD, rD; /* << 5 */ \
+ srl rD, rD; /* << 6 */ \
+ srl rD, rD; /* << 7 */ \
+ srl rD, rD; /* << 8 */ \
+ srl rD, rD; /* << 9 */ \
+ srl rD, rD /* << 10 */
+ #define BSRLI20(rD, rA) \
+ BSRLI10(rD, rA); \
+ BSRLI10(rD, rD)
+ #endif
+#endif /* CONFIG_MMU */
+
.extern other_exception_handler /* Defined in exception.c */

/*
@@ -163,34 +232,119 @@

/* wrappers to restore state before coming to entry.S */

+#ifdef CONFIG_MMU
+.section .rodata
+.align 4
+_MB_HW_ExceptionVectorTable:
+/* 0 - Undefined */
+ .long TOPHYS(ex_handler_unhandled)
+/* 1 - Unaligned data access exception */
+ .long TOPHYS(handle_unaligned_ex)
+/* 2 - Illegal op-code exception */
+ .long TOPHYS(full_exception_trapw)
+/* 3 - Instruction bus error exception */
+ .long TOPHYS(full_exception_trapw)
+/* 4 - Data bus error exception */
+ .long TOPHYS(full_exception_trapw)
+/* 5 - Divide by zero exception */
+ .long TOPHYS(full_exception_trapw)
+/* 6 - Floating point unit exception */
+ .long TOPHYS(full_exception_trapw)
+/* 7 - Privileged instruction exception */
+ .long TOPHYS(full_exception_trapw)
+/* 8 - 15 - Undefined */
+ .long TOPHYS(ex_handler_unhandled)
+ .long TOPHYS(ex_handler_unhandled)
+ .long TOPHYS(ex_handler_unhandled)
+ .long TOPHYS(ex_handler_unhandled)
+ .long TOPHYS(ex_handler_unhandled)
+ .long TOPHYS(ex_handler_unhandled)
+ .long TOPHYS(ex_handler_unhandled)
+ .long TOPHYS(ex_handler_unhandled)
+/* 16 - Data storage exception */
+ .long TOPHYS(handle_data_storage_exception)
+/* 17 - Instruction storage exception */
+ .long TOPHYS(handle_instruction_storage_exception)
+/* 18 - Data TLB miss exception */
+ .long TOPHYS(handle_data_tlb_miss_exception)
+/* 19 - Instruction TLB miss exception */
+ .long TOPHYS(handle_instruction_tlb_miss_exception)
+/* 20 - 31 - Undefined */
+ .long TOPHYS(ex_handler_unhandled)
+ .long TOPHYS(ex_handler_unhandled)
+ .long TOPHYS(ex_handler_unhandled)
+ .long TOPHYS(ex_handler_unhandled)
+ .long TOPHYS(ex_handler_unhandled)
+ .long TOPHYS(ex_handler_unhandled)
+ .long TOPHYS(ex_handler_unhandled)
+ .long TOPHYS(ex_handler_unhandled)
+ .long TOPHYS(ex_handler_unhandled)
+ .long TOPHYS(ex_handler_unhandled)
+ .long TOPHYS(ex_handler_unhandled)
+ .long TOPHYS(ex_handler_unhandled)
+#endif
+
.global _hw_exception_handler
.section .text
.align 4
.ent _hw_exception_handler
_hw_exception_handler:
+#ifndef CONFIG_MMU
addik r1, r1, -(EX_HANDLER_STACK_SIZ); /* Create stack frame */
+#else
+ swi r1, r0, TOPHYS(r0_ram + 0); /* GET_SP */
+ /* Save date to kernel memory. Here is the problem
+ * when you came from user space */
+ ori r1, r0, TOPHYS(r0_ram + 28);
+#endif
swi r3, r1, PT_R3
swi r4, r1, PT_R4
swi r5, r1, PT_R5
swi r6, r1, PT_R6

- mfs r5, rmsr;
- nop
- swi r5, r1, 0;
- mfs r4, rbtr /* Save BTR before jumping to handler */
- nop
+#ifdef CONFIG_MMU
+ swi r11, r1, PT_R11
+ swi r31, r1, PT_R31
+ lwi r31, r0, TOPHYS(PER_CPU(CURRENT_SAVE)) /* get saved current */
+#endif
+
mfs r3, resr
nop
+ mfs r4, rear;
+ nop

+#ifndef CONFIG_MMU
andi r5, r3, 0x1000; /* Check ESR[DS] */
beqi r5, not_in_delay_slot; /* Branch if ESR[DS] not set */
mfs r17, rbtr; /* ESR[DS] set - return address in BTR */
nop
not_in_delay_slot:
swi r17, r1, PT_R17
+#endif

andi r5, r3, 0x1F; /* Extract ESR[EXC] */

+#ifdef CONFIG_MMU
+ /* Calculate exception vector offset = r5 << 2 */
+ addk r6, r5, r5; /* << 1 */
+ addk r6, r6, r6; /* << 2 */
+
+/* counting which exception happen */
+ lwi r5, r0, 0x200 + TOPHYS(r0_ram)
+ addi r5, r5, 1
+ swi r5, r0, 0x200 + TOPHYS(r0_ram)
+ lwi r5, r6, 0x200 + TOPHYS(r0_ram)
+ addi r5, r5, 1
+ swi r5, r6, 0x200 + TOPHYS(r0_ram)
+/* end */
+ /* Load the HW Exception vector */
+ lwi r6, r6, TOPHYS(_MB_HW_ExceptionVectorTable)
+ bra r6
+
+full_exception_trapw:
+ RESTORE_STATE
+ bri full_exception_trap
+#else
/* Exceptions enabled here. This will allow nested exceptions */
mfs r6, rmsr;
nop
@@ -254,6 +408,7 @@ handle_other_ex: /* Handle Other exceptions here */
lwi r18, r1, PT_R18

bri ex_handler_done; /* Complete exception handling */
+#endif

/* 0x01 - Unaligned data access exception
* This occurs when a word access is not aligned on a word boundary,
@@ -265,11 +420,28 @@ handle_other_ex: /* Handle Other exceptions here */
handle_unaligned_ex:
/* Working registers already saved: R3, R4, R5, R6
* R3 = ESR
- * R4 = BTR
+ * R4 = EAR
*/
- mfs r4, rear;
+#ifdef CONFIG_MMU
+ andi r6, r3, 0x1000 /* Check ESR[DS] */
+ beqi r6, _no_delayslot /* Branch if ESR[DS] not set */
+ mfs r17, rbtr; /* ESR[DS] set - return address in BTR */
nop
+_no_delayslot:
+#endif
+
+#ifdef CONFIG_MMU
+ /* Check if unaligned address is last on a 4k page */
+ andi r5, r4, 0xffc
+ xori r5, r5, 0xffc
+ bnei r5, _unaligned_ex2
+ _unaligned_ex1:
+ RESTORE_STATE;
+/* Another page must be accessed or physical address not in page table */
+ bri unaligned_data_trap

+ _unaligned_ex2:
+#endif
andi r6, r3, 0x3E0; /* Mask and extract the register operand */
srl r6, r6; /* r6 >> 5 */
srl r6, r6;
@@ -278,6 +450,45 @@ handle_unaligned_ex:
srl r6, r6;
/* Store the register operand in a temporary location */
sbi r6, r0, TOPHYS(ex_reg_op);
+#ifdef CONFIG_MMU
+ /* Get physical address */
+ /* If we are faulting a kernel address, we have to use the
+ * kernel page tables.
+ */
+ ori r5, r0, CONFIG_KERNEL_START
+ cmpu r5, r4, r5
+ bgti r5, _unaligned_ex3
+ ori r5, r0, swapper_pg_dir
+ bri _unaligned_ex4
+
+ /* Get the PGD for the current thread. */
+_unaligned_ex3: /* user thread */
+ addi r5 ,CURRENT_TASK, TOPHYS(0); /* get current task address */
+ lwi r5, r5, TASK_THREAD + PGDIR
+_unaligned_ex4:
+ tophys(r5,r5)
+ BSRLI(r6,r4,20) /* Create L1 (pgdir/pmd) address */
+ andi r6, r6, 0xffc
+/* Assume pgdir aligned on 4K boundary, no need for "andi r5,r5,0xfffff003" */
+ or r5, r5, r6
+ lwi r6, r5, 0 /* Get L1 entry */
+ andi r5, r6, 0xfffff000 /* Extract L2 (pte) base address. */
+ beqi r5, _unaligned_ex1 /* Bail if no table */
+
+ tophys(r5,r5)
+ BSRLI(r6,r4,10) /* Compute PTE address */
+ andi r6, r6, 0xffc
+ andi r5, r5, 0xfffff003
+ or r5, r5, r6
+ lwi r5, r5, 0 /* Get Linux PTE */
+
+ andi r6, r5, _PAGE_PRESENT
+ beqi r6, _unaligned_ex1 /* Bail if no page */
+
+ andi r5, r5, 0xfffff000 /* Extract RPN */
+ andi r4, r4, 0x00000fff /* Extract offset */
+ or r4, r4, r5 /* Create physical address */
+#endif /* CONFIG_MMU */

andi r6, r3, 0x400; /* Extract ESR[S] */
bnei r6, ex_sw;
@@ -355,6 +566,7 @@ ex_shw:
ex_sw_end: /* Exception handling of store word, ends. */

ex_handler_done:
+#ifndef CONFIG_MMU
lwi r5, r1, 0 /* RMSR */
mts rmsr, r5
nop
@@ -366,13 +578,455 @@ ex_handler_done:

rted r17, 0
addik r1, r1, (EX_HANDLER_STACK_SIZ); /* Restore stack frame */
+#else
+ RESTORE_STATE;
+ rted r17, 0
+ nop
+#endif
+
+#ifdef CONFIG_MMU
+ /* Exception vector entry code. This code runs with address translation
+ * turned off (i.e. using physical addresses). */
+
+ /* Exception vectors. */
+
+ /* 0x10 - Data Storage Exception
+ * This happens for just a few reasons. U0 set (but we don't do that),
+ * or zone protection fault (user violation, write to protected page).
+ * If this is just an update of modified status, we do that quickly
+ * and exit. Otherwise, we call heavyweight functions to do the work.
+ */
+ handle_data_storage_exception:
+ /* Working registers already saved: R3, R4, R5, R6
+ * R3 = ESR
+ */
+ mfs r11, rpid
+ nop
+ bri 4
+ mfs r3, rear /* Get faulting address */
+ nop
+ /* If we are faulting a kernel address, we have to use the
+ * kernel page tables.
+ */
+ ori r4, r0, CONFIG_KERNEL_START
+ cmpu r4, r3, r4
+ bgti r4, ex3
+ /* First, check if it was a zone fault (which means a user
+ * tried to access a kernel or read-protected page - always
+ * a SEGV). All other faults here must be stores, so no
+ * need to check ESR_S as well. */
+ mfs r4, resr
+ nop
+ andi r4, r4, 0x800 /* ESR_Z - zone protection */
+ bnei r4, ex2
+
+ ori r4, r0, swapper_pg_dir
+ mts rpid, r0 /* TLB will have 0 TID */
+ nop
+ bri ex4
+
+ /* Get the PGD for the current thread. */
+ ex3:
+ /* First, check if it was a zone fault (which means a user
+ * tried to access a kernel or read-protected page - always
+ * a SEGV). All other faults here must be stores, so no
+ * need to check ESR_S as well. */
+ mfs r4, resr
+ nop
+ andi r4, r4, 0x800 /* ESR_Z */
+ bnei r4, ex2
+ /* get current task address */
+ addi r4 ,CURRENT_TASK, TOPHYS(0);
+ lwi r4, r4, TASK_THREAD+PGDIR
+ ex4:
+ tophys(r4,r4)
+ BSRLI(r5,r3,20) /* Create L1 (pgdir/pmd) address */
+ andi r5, r5, 0xffc
+/* Assume pgdir aligned on 4K boundary, no need for "andi r4,r4,0xfffff003" */
+ or r4, r4, r5
+ lwi r4, r4, 0 /* Get L1 entry */
+ andi r5, r4, 0xfffff000 /* Extract L2 (pte) base address */
+ beqi r5, ex2 /* Bail if no table */
+
+ tophys(r5,r5)
+ BSRLI(r6,r3,10) /* Compute PTE address */
+ andi r6, r6, 0xffc
+ andi r5, r5, 0xfffff003
+ or r5, r5, r6
+ lwi r4, r5, 0 /* Get Linux PTE */
+
+ andi r6, r4, _PAGE_RW /* Is it writeable? */
+ beqi r6, ex2 /* Bail if not */
+
+ /* Update 'changed' */
+ ori r4, r4, _PAGE_DIRTY|_PAGE_ACCESSED|_PAGE_HWWRITE
+ swi r4, r5, 0 /* Update Linux page table */
+
+ /* Most of the Linux PTE is ready to load into the TLB LO.
+ * We set ZSEL, where only the LS-bit determines user access.
+ * We set execute, because we don't have the granularity to
+ * properly set this at the page level (Linux problem).
+ * If shared is set, we cause a zero PID->TID load.
+ * Many of these bits are software only. Bits we don't set
+ * here we (properly should) assume have the appropriate value.
+ */
+ andni r4, r4, 0x0ce2 /* Make sure 20, 21 are zero */
+ ori r4, r4, _PAGE_HWEXEC /* make it executable */
+
+ /* find the TLB index that caused the fault. It has to be here*/
+ mts rtlbsx, r3
+ nop
+ mfs r5, rtlbx /* DEBUG: TBD */
+ nop
+ mts rtlblo, r4 /* Load TLB LO */
+ nop
+ /* Will sync shadow TLBs */
+
+ /* Done...restore registers and get out of here. */
+ mts rpid, r11
+ nop
+ bri 4
+
+ RESTORE_STATE;
+ rted r17, 0
+ nop
+ ex2:
+ /* The bailout. Restore registers to pre-exception conditions
+ * and call the heavyweights to help us out. */
+ mts rpid, r11
+ nop
+ bri 4
+ RESTORE_STATE;
+ bri page_fault_data_trap
+
+
+ /* 0x11 - Instruction Storage Exception
+ * This is caused by a fetch from non-execute or guarded pages. */
+ handle_instruction_storage_exception:
+ /* Working registers already saved: R3, R4, R5, R6
+ * R3 = ESR
+ */
+
+ mfs r3, rear /* Get faulting address */
+ nop
+ RESTORE_STATE;
+ bri page_fault_instr_trap
+
+ /* 0x12 - Data TLB Miss Exception
+ * As the name implies, translation is not in the MMU, so search the
+ * page tables and fix it. The only purpose of this function is to
+ * load TLB entries from the page table if they exist.
+ */
+ handle_data_tlb_miss_exception:
+ /* Working registers already saved: R3, R4, R5, R6
+ * R3 = ESR
+ */
+ mfs r11, rpid
+ nop
+ bri 4
+ mfs r3, rear /* Get faulting address */
+ nop
+
+ /* If we are faulting a kernel address, we have to use the
+ * kernel page tables. */
+ ori r4, r0, CONFIG_KERNEL_START
+ cmpu r4, r3, r4
+ bgti r4, ex5
+ ori r4, r0, swapper_pg_dir
+ mts rpid, r0 /* TLB will have 0 TID */
+ nop
+ bri ex6

+ /* Get the PGD for the current thread. */
+ ex5:
+ /* get current task address */
+ addi r4 ,CURRENT_TASK, TOPHYS(0);
+ lwi r4, r4, TASK_THREAD+PGDIR
+ ex6:
+ tophys(r4,r4)
+ BSRLI(r5,r3,20) /* Create L1 (pgdir/pmd) address */
+ andi r5, r5, 0xffc
+/* Assume pgdir aligned on 4K boundary, no need for "andi r4,r4,0xfffff003" */
+ or r4, r4, r5
+ lwi r4, r4, 0 /* Get L1 entry */
+ andi r5, r4, 0xfffff000 /* Extract L2 (pte) base address */
+ beqi r5, ex7 /* Bail if no table */
+
+ tophys(r5,r5)
+ BSRLI(r6,r3,10) /* Compute PTE address */
+ andi r6, r6, 0xffc
+ andi r5, r5, 0xfffff003
+ or r5, r5, r6
+ lwi r4, r5, 0 /* Get Linux PTE */
+
+ andi r6, r4, _PAGE_PRESENT
+ beqi r6, ex7
+
+ ori r4, r4, _PAGE_ACCESSED
+ swi r4, r5, 0
+
+ /* Most of the Linux PTE is ready to load into the TLB LO.
+ * We set ZSEL, where only the LS-bit determines user access.
+ * We set execute, because we don't have the granularity to
+ * properly set this at the page level (Linux problem).
+ * If shared is set, we cause a zero PID->TID load.
+ * Many of these bits are software only. Bits we don't set
+ * here we (properly should) assume have the appropriate value.
+ */
+ andni r4, r4, 0x0ce2 /* Make sure 20, 21 are zero */
+
+ bri finish_tlb_load
+ ex7:
+ /* The bailout. Restore registers to pre-exception conditions
+ * and call the heavyweights to help us out.
+ */
+ mts rpid, r11
+ nop
+ bri 4
+ RESTORE_STATE;
+ bri page_fault_data_trap
+
+ /* 0x13 - Instruction TLB Miss Exception
+ * Nearly the same as above, except we get our information from
+ * different registers and bailout to a different point.
+ */
+ handle_instruction_tlb_miss_exception:
+ /* Working registers already saved: R3, R4, R5, R6
+ * R3 = ESR
+ */
+ mfs r11, rpid
+ nop
+ bri 4
+ mfs r3, rear /* Get faulting address */
+ nop
+
+ /* If we are faulting a kernel address, we have to use the
+ * kernel page tables.
+ */
+ ori r4, r0, CONFIG_KERNEL_START
+ cmpu r4, r3, r4
+ bgti r4, ex8
+ ori r4, r0, swapper_pg_dir
+ mts rpid, r0 /* TLB will have 0 TID */
+ nop
+ bri ex9
+
+ /* Get the PGD for the current thread. */
+ ex8:
+ /* get current task address */
+ addi r4 ,CURRENT_TASK, TOPHYS(0);
+ lwi r4, r4, TASK_THREAD+PGDIR
+ ex9:
+ tophys(r4,r4)
+ BSRLI(r5,r3,20) /* Create L1 (pgdir/pmd) address */
+ andi r5, r5, 0xffc
+/* Assume pgdir aligned on 4K boundary, no need for "andi r4,r4,0xfffff003" */
+ or r4, r4, r5
+ lwi r4, r4, 0 /* Get L1 entry */
+ andi r5, r4, 0xfffff000 /* Extract L2 (pte) base address */
+ beqi r5, ex10 /* Bail if no table */
+
+ tophys(r5,r5)
+ BSRLI(r6,r3,10) /* Compute PTE address */
+ andi r6, r6, 0xffc
+ andi r5, r5, 0xfffff003
+ or r5, r5, r6
+ lwi r4, r5, 0 /* Get Linux PTE */
+
+ andi r6, r4, _PAGE_PRESENT
+ beqi r6, ex7
+
+ ori r4, r4, _PAGE_ACCESSED
+ swi r4, r5, 0
+
+ /* Most of the Linux PTE is ready to load into the TLB LO.
+ * We set ZSEL, where only the LS-bit determines user access.
+ * We set execute, because we don't have the granularity to
+ * properly set this at the page level (Linux problem).
+ * If shared is set, we cause a zero PID->TID load.
+ * Many of these bits are software only. Bits we don't set
+ * here we (properly should) assume have the appropriate value.
+ */
+ andni r4, r4, 0x0ce2 /* Make sure 20, 21 are zero */
+
+ bri finish_tlb_load
+ ex10:
+ /* The bailout. Restore registers to pre-exception conditions
+ * and call the heavyweights to help us out.
+ */
+ mts rpid, r11
+ nop
+ bri 4
+ RESTORE_STATE;
+ bri page_fault_instr_trap
+
+/* Both the instruction and data TLB miss get to this point to load the TLB.
+ * r3 - EA of fault
+ * r4 - TLB LO (info from Linux PTE)
+ * r5, r6 - available to use
+ * PID - loaded with proper value when we get here
+ * Upon exit, we reload everything and RFI.
+ * A common place to load the TLB.
+ */
+ tlb_index:
+ .long 1 /* MS: storing last used tlb index */
+ finish_tlb_load:
+ /* MS: load the last used TLB index. */
+ lwi r5, r0, TOPHYS(tlb_index)
+ addik r5, r5, 1 /* MS: inc tlb_index -> use next one */
+
+/* MS: FIXME this is potential fault, because this is mask not count */
+ andi r5, r5, (MICROBLAZE_TLB_SIZE-1)
+ ori r6, r0, 1
+ cmp r31, r5, r6
+ blti r31, sem
+ addik r5, r6, 1
+ sem:
+ /* MS: save back current TLB index */
+ swi r5, r0, TOPHYS(tlb_index)
+
+ ori r4, r4, _PAGE_HWEXEC /* make it executable */
+ mts rtlbx, r5 /* MS: save current TLB */
+ nop
+ mts rtlblo, r4 /* MS: save to TLB LO */
+ nop
+
+ /* Create EPN. This is the faulting address plus a static
+ * set of bits. These are size, valid, E, U0, and ensure
+ * bits 20 and 21 are zero.
+ */
+ andi r3, r3, 0xfffff000
+ ori r3, r3, 0x0c0
+ mts rtlbhi, r3 /* Load TLB HI */
+ nop
+
+ /* Done...restore registers and get out of here. */
+ ex12:
+ mts rpid, r11
+ nop
+ bri 4
+ RESTORE_STATE;
+ rted r17, 0
+ nop
+
+ /* extern void giveup_fpu(struct task_struct *prev)
+ *
+ * The MicroBlaze processor may have an FPU, so this should not just
+ * return: TBD.
+ */
+ .globl giveup_fpu;
+ .align 4;
+ giveup_fpu:
+ bralid r15,0 /* TBD */
+ nop
+
+ /* At present, this routine just hangs. - extern void abort(void) */
+ .globl abort;
+ .align 4;
+ abort:
+ br r0
+
+ .globl set_context;
+ .align 4;
+ set_context:
+ mts rpid, r5 /* Shadow TLBs are automatically */
+ nop
+ bri 4 /* flushed by changing PID */
+ rtsd r15,8
+ nop
+
+#endif
.end _hw_exception_handler

+#ifdef CONFIG_MMU
+/* Unaligned data access exception last on a 4k page for MMU.
+ * When this is called, we are in virtual mode with exceptions enabled
+ * and registers 1-13,15,17,18 saved.
+ *
+ * R3 = ESR
+ * R4 = EAR
+ * R7 = pointer to saved registers (struct pt_regs *regs)
+ *
+ * This handler perform the access, and returns via ret_from_exc.
+ */
+.global _unaligned_data_exception
+.ent _unaligned_data_exception
+_unaligned_data_exception:
+ andi r8, r3, 0x3E0; /* Mask and extract the register operand */
+ BSRLI(r8,r8,2); /* r8 >> 2 = register operand * 8 */
+ andi r6, r3, 0x400; /* Extract ESR[S] */
+ bneid r6, ex_sw_vm;
+ andi r6, r3, 0x800; /* Extract ESR[W] - delay slot */
+ex_lw_vm:
+ beqid r6, ex_lhw_vm;
+ lbui r5, r4, 0; /* Exception address in r4 - delay slot */
+/* Load a word, byte-by-byte from destination address and save it in tmp space*/
+ la r6, r0, ex_tmp_data_loc_0;
+ sbi r5, r6, 0;
+ lbui r5, r4, 1;
+ sbi r5, r6, 1;
+ lbui r5, r4, 2;
+ sbi r5, r6, 2;
+ lbui r5, r4, 3;
+ sbi r5, r6, 3;
+ brid ex_lw_tail_vm;
+/* Get the destination register value into r3 - delay slot */
+ lwi r3, r6, 0;
+ex_lhw_vm:
+ /* Load a half-word, byte-by-byte from destination address and
+ * save it in tmp space */
+ la r6, r0, ex_tmp_data_loc_0;
+ sbi r5, r6, 0;
+ lbui r5, r4, 1;
+ sbi r5, r6, 1;
+ lhui r3, r6, 0; /* Get the destination register value into r3 */
+ex_lw_tail_vm:
+ /* Form load_word jump table offset (lw_table_vm + (8 * regnum)) */
+ addik r5, r8, lw_table_vm;
+ bra r5;
+ex_lw_end_vm: /* Exception handling of load word, ends */
+ brai ret_from_exc;
+ex_sw_vm:
+/* Form store_word jump table offset (sw_table_vm + (8 * regnum)) */
+ addik r5, r8, sw_table_vm;
+ bra r5;
+ex_sw_tail_vm:
+ la r5, r0, ex_tmp_data_loc_0;
+ beqid r6, ex_shw_vm;
+ swi r3, r5, 0; /* Get the word - delay slot */
+ /* Store the word, byte-by-byte into destination address */
+ lbui r3, r5, 0;
+ sbi r3, r4, 0;
+ lbui r3, r5, 1;
+ sbi r3, r4, 1;
+ lbui r3, r5, 2;
+ sbi r3, r4, 2;
+ lbui r3, r5, 3;
+ brid ret_from_exc;
+ sbi r3, r4, 3; /* Delay slot */
+ex_shw_vm:
+ /* Store the lower half-word, byte-by-byte into destination address */
+ lbui r3, r5, 2;
+ sbi r3, r4, 0;
+ lbui r3, r5, 3;
+ brid ret_from_exc;
+ sbi r3, r4, 1; /* Delay slot */
+ex_sw_end_vm: /* Exception handling of store word, ends. */
+.end _unaligned_data_exception
+#endif /* CONFIG_MMU */
+
ex_handler_unhandled:
/* FIXME add handle function for unhandled exception - dump register */
bri 0

+/*
+ * hw_exception_handler Jump Table
+ * - Contains code snippets for each register that caused the unalign exception
+ * - Hence exception handler is NOT self-modifying
+ * - Separate table for load exceptions and store exceptions.
+ * - Each table is of size: (8 * 32) = 256 bytes
+ */
+
.section .text
.align 4
lw_table:
@@ -407,7 +1061,11 @@ lw_r27: R3_TO_LWREG (27);
lw_r28: R3_TO_LWREG (28);
lw_r29: R3_TO_LWREG (29);
lw_r30: R3_TO_LWREG (30);
+#ifdef CONFIG_MMU
+lw_r31: R3_TO_LWREG_V (31);
+#else
lw_r31: R3_TO_LWREG (31);
+#endif

sw_table:
sw_r0: SWREG_TO_R3 (0);
@@ -441,7 +1099,81 @@ sw_r27: SWREG_TO_R3 (27);
sw_r28: SWREG_TO_R3 (28);
sw_r29: SWREG_TO_R3 (29);
sw_r30: SWREG_TO_R3 (30);
+#ifdef CONFIG_MMU
+sw_r31: SWREG_TO_R3_V (31);
+#else
sw_r31: SWREG_TO_R3 (31);
+#endif
+
+#ifdef CONFIG_MMU
+lw_table_vm:
+lw_r0_vm: R3_TO_LWREG_VM (0);
+lw_r1_vm: R3_TO_LWREG_VM_V (1);
+lw_r2_vm: R3_TO_LWREG_VM_V (2);
+lw_r3_vm: R3_TO_LWREG_VM_V (3);
+lw_r4_vm: R3_TO_LWREG_VM_V (4);
+lw_r5_vm: R3_TO_LWREG_VM_V (5);
+lw_r6_vm: R3_TO_LWREG_VM_V (6);
+lw_r7_vm: R3_TO_LWREG_VM_V (7);
+lw_r8_vm: R3_TO_LWREG_VM_V (8);
+lw_r9_vm: R3_TO_LWREG_VM_V (9);
+lw_r10_vm: R3_TO_LWREG_VM_V (10);
+lw_r11_vm: R3_TO_LWREG_VM_V (11);
+lw_r12_vm: R3_TO_LWREG_VM_V (12);
+lw_r13_vm: R3_TO_LWREG_VM_V (13);
+lw_r14_vm: R3_TO_LWREG_VM (14);
+lw_r15_vm: R3_TO_LWREG_VM_V (15);
+lw_r16_vm: R3_TO_LWREG_VM (16);
+lw_r17_vm: R3_TO_LWREG_VM_V (17);
+lw_r18_vm: R3_TO_LWREG_VM_V (18);
+lw_r19_vm: R3_TO_LWREG_VM (19);
+lw_r20_vm: R3_TO_LWREG_VM (20);
+lw_r21_vm: R3_TO_LWREG_VM (21);
+lw_r22_vm: R3_TO_LWREG_VM (22);
+lw_r23_vm: R3_TO_LWREG_VM (23);
+lw_r24_vm: R3_TO_LWREG_VM (24);
+lw_r25_vm: R3_TO_LWREG_VM (25);
+lw_r26_vm: R3_TO_LWREG_VM (26);
+lw_r27_vm: R3_TO_LWREG_VM (27);
+lw_r28_vm: R3_TO_LWREG_VM (28);
+lw_r29_vm: R3_TO_LWREG_VM (29);
+lw_r30_vm: R3_TO_LWREG_VM (30);
+lw_r31_vm: R3_TO_LWREG_VM_V (31);
+
+sw_table_vm:
+sw_r0_vm: SWREG_TO_R3_VM (0);
+sw_r1_vm: SWREG_TO_R3_VM_V (1);
+sw_r2_vm: SWREG_TO_R3_VM_V (2);
+sw_r3_vm: SWREG_TO_R3_VM_V (3);
+sw_r4_vm: SWREG_TO_R3_VM_V (4);
+sw_r5_vm: SWREG_TO_R3_VM_V (5);
+sw_r6_vm: SWREG_TO_R3_VM_V (6);
+sw_r7_vm: SWREG_TO_R3_VM_V (7);
+sw_r8_vm: SWREG_TO_R3_VM_V (8);
+sw_r9_vm: SWREG_TO_R3_VM_V (9);
+sw_r10_vm: SWREG_TO_R3_VM_V (10);
+sw_r11_vm: SWREG_TO_R3_VM_V (11);
+sw_r12_vm: SWREG_TO_R3_VM_V (12);
+sw_r13_vm: SWREG_TO_R3_VM_V (13);
+sw_r14_vm: SWREG_TO_R3_VM (14);
+sw_r15_vm: SWREG_TO_R3_VM_V (15);
+sw_r16_vm: SWREG_TO_R3_VM (16);
+sw_r17_vm: SWREG_TO_R3_VM_V (17);
+sw_r18_vm: SWREG_TO_R3_VM_V (18);
+sw_r19_vm: SWREG_TO_R3_VM (19);
+sw_r20_vm: SWREG_TO_R3_VM (20);
+sw_r21_vm: SWREG_TO_R3_VM (21);
+sw_r22_vm: SWREG_TO_R3_VM (22);
+sw_r23_vm: SWREG_TO_R3_VM (23);
+sw_r24_vm: SWREG_TO_R3_VM (24);
+sw_r25_vm: SWREG_TO_R3_VM (25);
+sw_r26_vm: SWREG_TO_R3_VM (26);
+sw_r27_vm: SWREG_TO_R3_VM (27);
+sw_r28_vm: SWREG_TO_R3_VM (28);
+sw_r29_vm: SWREG_TO_R3_VM (29);
+sw_r30_vm: SWREG_TO_R3_VM (30);
+sw_r31_vm: SWREG_TO_R3_VM_V (31);
+#endif /* CONFIG_MMU */

/* Temporary data structures used in the handler */
.section .data
--
1.5.5.1


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