patch-2.2.8 linux/arch/arm/mm/fault-armv.c

• Lines: 643
• Date: Sat May 8 11:06:56 1999
• Orig file: v2.2.7/linux/arch/arm/mm/fault-armv.c
• Orig date: Tue Dec 22 14:16:53 1998

diff -u --recursive --new-file v2.2.7/linux/arch/arm/mm/fault-armv.c linux/arch/arm/mm/fault-armv.c
@@ -1,10 +1,11 @@
 /*
- *  linux/arch/arm/mm/fault.c
+ *  linux/arch/arm/mm/fault-armv.c
  *
  *  Copyright (C) 1995  Linus Torvalds
- *  Modifications for ARM processor (c) 1995, 1996 Russell King
+ *  Modifications for ARM processor (c) 1995-1999 Russell King
  */
 
+#include <linux/config.h>
 #include <linux/signal.h>
 #include <linux/sched.h>
 #include <linux/kernel.h>
@@ -14,43 +15,37 @@
 #include <linux/ptrace.h>
 #include <linux/mman.h>
 #include <linux/mm.h>
-#include <linux/smp.h>
-#include <linux/smp_lock.h>
+#include <linux/interrupt.h>
+#include <linux/proc_fs.h>
+#include <linux/init.h>
 
 #include <asm/system.h>
 #include <asm/uaccess.h>
 #include <asm/pgtable.h>
+#include <asm/unaligned.h>
 
 #define FAULT_CODE_READ		0x02
 #define FAULT_CODE_USER		0x01
 
-struct pgtable_cache_struct quicklists;
+#define DO_COW(m)		(!((m) & FAULT_CODE_READ))
+#define READ_FAULT(m)		((m) & FAULT_CODE_READ)
 
-void __bad_pmd(pmd_t *pmd)
-{
-	printk("Bad pmd in pte_alloc: %08lx\n", pmd_val(*pmd));
-	set_pmd(pmd, mk_user_pmd(BAD_PAGETABLE));
-}
-
-void __bad_pmd_kernel(pmd_t *pmd)
-{
-	printk("Bad pmd in pte_alloc: %08lx\n", pmd_val(*pmd));
-	set_pmd(pmd, mk_kernel_pmd(BAD_PAGETABLE));
-}
+#include "fault-common.c"
 
 pgd_t *get_pgd_slow(void)
 {
 	/*
 	 * need to get a 16k page for level 1
 	 */
-	pgd_t *pgd = (pgd_t *) __get_free_pages(GFP_KERNEL,2);
+	pgd_t *pgd = (pgd_t *)__get_free_pages(GFP_KERNEL,2);
 	pgd_t *init;
-	
+
 	if (pgd) {
 		init = pgd_offset(&init_mm, 0);
-		memzero ((void *)pgd, USER_PTRS_PER_PGD * BYTES_PER_PTR);
-		memcpy (pgd + USER_PTRS_PER_PGD, init + USER_PTRS_PER_PGD,
+		memzero(pgd, USER_PTRS_PER_PGD * BYTES_PER_PTR);
+		memcpy(pgd + USER_PTRS_PER_PGD, init + USER_PTRS_PER_PGD,
 			(PTRS_PER_PGD - USER_PTRS_PER_PGD) * BYTES_PER_PTR);
+		clean_cache_area(pgd, PTRS_PER_PGD * BYTES_PER_PTR);
 	}
 	return pgd;
 }
@@ -59,17 +54,19 @@
 {
 	pte_t *pte;
 
-	pte = (pte_t *) get_small_page(GFP_KERNEL);
+	pte = (pte_t *)get_page_2k(GFP_KERNEL);
 	if (pmd_none(*pmd)) {
 		if (pte) {
-			memzero (pte, PTRS_PER_PTE * BYTES_PER_PTR);
+			memzero(pte, 2 * PTRS_PER_PTE * BYTES_PER_PTR);
+			clean_cache_area(pte, PTRS_PER_PTE * BYTES_PER_PTR);
+			pte += PTRS_PER_PTE;
 			set_pmd(pmd, mk_user_pmd(pte));
 			return pte + offset;
 		}
 		set_pmd(pmd, mk_user_pmd(BAD_PAGETABLE));
 		return NULL;
 	}
-	free_small_page ((unsigned long) pte);
+	free_page_2k((unsigned long)pte);
 	if (pmd_bad(*pmd)) {
 		__bad_pmd(pmd);
 		return NULL;
@@ -81,17 +78,19 @@
 {
 	pte_t *pte;
 
-	pte = (pte_t *) get_small_page(GFP_KERNEL);
+	pte = (pte_t *)get_page_2k(GFP_KERNEL);
 	if (pmd_none(*pmd)) {
 		if (pte) {
-			memzero (pte, PTRS_PER_PTE * BYTES_PER_PTR);
+			memzero(pte, 2 * PTRS_PER_PTE * BYTES_PER_PTR);
+			clean_cache_area(pte, PTRS_PER_PTE * BYTES_PER_PTR);
+			pte += PTRS_PER_PTE;
 			set_pmd(pmd, mk_kernel_pmd(pte));
 			return pte + offset;
 		}
 		set_pmd(pmd, mk_kernel_pmd(BAD_PAGETABLE));
 		return NULL;
 	}
-	free_small_page ((unsigned long) pte);
+	free_page_2k((unsigned long)pte);
 	if (pmd_bad(*pmd)) {
 		__bad_pmd_kernel(pmd);
 		return NULL;
@@ -99,10 +98,8 @@
 	return (pte_t *) pmd_page(*pmd) + offset;
 }
 
-extern void die_if_kernel(char *msg, struct pt_regs *regs, unsigned int err, unsigned int ret);
-
 #ifdef DEBUG
-static int sp_valid (unsigned long *sp)
+static int sp_valid(unsigned long *sp)
 {
 	unsigned long addr = (unsigned long) sp;
 
@@ -114,187 +111,371 @@
 }
 #endif
 
-static void kernel_page_fault (unsigned long addr, int mode, struct pt_regs *regs,
-			       struct task_struct *tsk, struct mm_struct *mm)
+#ifdef CONFIG_ALIGNMENT_TRAP
+/*
+ * 32-bit misaligned trap handler (c) 1998 San Mehat (CCC) -July 1998
+ * /proc/sys/debug/alignment, modified and integrated into
+ * Linux 2.1 by Russell King
+ *
+ * NOTE!!! This is not portable onto the ARM6/ARM7 processors yet.  Also,
+ * it seems to give a severe performance impact (1 abort/ms - NW runs at
+ * ARM6 speeds) with GCC 2.7.2.2 - needs checking with a later GCC/EGCS.
+ *
+ * IMHO, I don't think that the trap handler is advantageous on ARM6,7
+ * processors (they'll run like an ARM3).  We'll see.
+ */
+#define CODING_BITS(i)	(i & 0x0e000000)
+
+#define LDST_I_BIT(i)	(i & (1 << 26))		/* Immediate constant	*/
+#define LDST_P_BIT(i)	(i & (1 << 24))		/* Preindex		*/
+#define LDST_U_BIT(i)	(i & (1 << 23))		/* Add offset		*/
+#define LDST_W_BIT(i)	(i & (1 << 21))		/* Writeback		*/
+#define LDST_L_BIT(i)	(i & (1 << 20))		/* Load			*/
+
+#define LDSTH_I_BIT(i)	(i & (1 << 22))		/* half-word immed	*/
+#define LDM_S_BIT(i)	(i & (1 << 22))		/* write CPSR from SPSR	*/
+
+#define RN_BITS(i)	((i >> 16) & 15)	/* Rn			*/
+#define RD_BITS(i)	((i >> 12) & 15)	/* Rd			*/
+#define RM_BITS(i)	(i & 15)		/* Rm			*/
+
+#define REGMASK_BITS(i)	(i & 0xffff)
+#define OFFSET_BITS(i)	(i & 0x0fff)
+
+#define IS_SHIFT(i)	(i & 0x0ff0)
+#define SHIFT_BITS(i)	((i >> 7) & 0x1f)
+#define SHIFT_TYPE(i)	(i & 0x60)
+#define SHIFT_LSL	0x00
+#define SHIFT_LSR	0x20
+#define SHIFT_ASR	0x40
+#define SHIFT_RORRRX	0x60
+
+static unsigned long ai_user;
+static unsigned long ai_sys;
+static unsigned long ai_skipped;
+static unsigned long ai_half;
+static unsigned long ai_word;
+static unsigned long ai_multi;
+
+static int proc_alignment_read(char *page, char **start, off_t off,
+			       int count, int *eof, void *data)
 {
-	/*
-	 * Oops. The kernel tried to access some bad page. We'll have to
-	 * terminate things with extreme prejudice.
-	 */
-	pgd_t *pgd;
-	if (addr < PAGE_SIZE)
-	    printk (KERN_ALERT "Unable to handle kernel NULL pointer dereference");
-	else
-	    printk (KERN_ALERT "Unable to handle kernel paging request");
-	printk (" at virtual address %08lx\n", addr);
-	printk (KERN_ALERT "current->tss.memmap = %08lX\n", tsk->tss.memmap);
-	pgd = pgd_offset (mm, addr);
-	printk (KERN_ALERT "*pgd = %08lx", pgd_val (*pgd));
-	if (!pgd_none (*pgd)) {
-		pmd_t *pmd;
-		pmd = pmd_offset (pgd, addr);
-		printk (", *pmd = %08lx", pmd_val (*pmd));
-		if (!pmd_none (*pmd))
-			printk (", *pte = %08lx", pte_val (*pte_offset (pmd, addr)));
-	}
-	printk ("\n");
-	die_if_kernel ("Oops", regs, mode, SIGKILL);
-	do_exit (SIGKILL);
+	char *p = page;
+	int len;
+
+	p += sprintf(p, "User:\t\t%li\n", ai_user);
+	p += sprintf(p, "System:\t\t%li\n", ai_sys);
+	p += sprintf(p, "Skipped:\t%li\n", ai_skipped);
+	p += sprintf(p, "Half:\t\t%li\n", ai_half);
+	p += sprintf(p, "Word:\t\t%li\n", ai_word);
+	p += sprintf(p, "Multi:\t\t%li\n", ai_multi);
+
+	len = (p - page) - off;
+	if (len < 0)
+		len = 0;
+
+	*eof = (len <= count) ? 1 : 0;
+	*start = page + off;
+
+	return len;
 }
 
-static void page_fault (unsigned long addr, int mode, struct pt_regs *regs)
+/*
+ * This needs to be done after sysctl_init, otherwise sys/
+ * will be overwritten.
+ */
+void __init alignment_init(void)
 {
-	struct task_struct *tsk;
-	struct mm_struct *mm;
-	struct vm_area_struct *vma;
-	unsigned long fixup;
-
-	lock_kernel();
-	tsk = current;
-	mm = tsk->mm;
-
-	down(&mm->mmap_sem);
-	vma = find_vma (mm, addr);
-	if (!vma)
-		goto bad_area;
-	if (vma->vm_start <= addr)
-		goto good_area;
-	if (!(vma->vm_flags & VM_GROWSDOWN) || expand_stack (vma, addr))
-		goto bad_area;
+	struct proc_dir_entry *e;
 
-	/*
-	 * Ok, we have a good vm_area for this memory access, so
-	 * we can handle it..
-	 */
-good_area:
-	if (mode & FAULT_CODE_READ) { /* read? */
-		if (!(vma->vm_flags & (VM_READ|VM_EXEC)))
-			goto bad_area;
-	} else {
-		if (!(vma->vm_flags & VM_WRITE))
-			goto bad_area;
+	e = create_proc_entry("sys/debug/alignment", S_IFREG | S_IRUGO, NULL);
+
+	if (e)
+		e->read_proc = proc_alignment_read;
+}
+
+static int
+do_alignment_exception(struct pt_regs *regs)
+{
+	unsigned int instr, rd, rn, correction, nr_regs, regbits;
+	unsigned long eaddr;
+	union { unsigned long un; signed long sn; } offset;
+
+	if (user_mode(regs)) {
+		set_cr(cr_no_alignment);
+		ai_user += 1;
+		return 0;
 	}
-	handle_mm_fault (tsk, vma, addr & PAGE_MASK, !(mode & FAULT_CODE_READ));
-	up(&mm->mmap_sem);
-	goto out;
 
-	/*
-	 * Something tried to access memory that isn't in our memory map..
-	 * Fix it, but check if it's kernel or user first..
-	 */
-bad_area:
-	up(&mm->mmap_sem);
-	if (mode & FAULT_CODE_USER) {
-		tsk->tss.error_code = mode;
-		tsk->tss.trap_no = 14;
-		printk ("%s: memory violation at pc=0x%08lx, lr=0x%08lx (bad address=0x%08lx, code %d)\n",
-			tsk->comm, regs->ARM_pc, regs->ARM_lr, addr, mode);
-#ifdef DEBUG
-		{
-			unsigned int i, j;
-			unsigned long *sp = (unsigned long *) (regs->ARM_sp - 128);
-			for (j = 0; j < 20 && sp_valid (sp); j++) {
-				printk ("%p: ", sp);
-				for (i = 0; i < 8 && sp_valid (sp); i += 1, sp++)
-					printk ("%08lx ", *sp);
-				printk ("\n");
+	ai_sys += 1;
+
+	instr = *(unsigned long *)instruction_pointer(regs);
+	correction = 4; /* sometimes 8 on ARMv3 */
+	regs->ARM_pc += correction + 4;
+
+	rd = RD_BITS(instr);
+	rn = RN_BITS(instr);
+	eaddr = regs->uregs[rn];
+
+	switch(CODING_BITS(instr)) {
+	case 0x00000000:
+		if ((instr & 0x0ff00ff0) == 0x01000090) {
+			ai_skipped += 1;
+			printk(KERN_ERR "Unaligned trap: not handling swp instruction\n");
+			return 1;
+		}
+
+		if (((instr & 0x0e000090) == 0x00000090) && (instr & 0x60) != 0) {
+			ai_half += 1;
+			if (LDSTH_I_BIT(instr))
+				offset.un = (instr & 0xf00) >> 4 | (instr & 15);
+			else
+				offset.un = regs->uregs[RM_BITS(instr)];
+
+			if (LDST_P_BIT(instr)) {
+				if (LDST_U_BIT(instr))
+					eaddr += offset.un;
+				else
+					eaddr -= offset.un;
 			}
+
+			if (LDST_L_BIT(instr))
+				regs->uregs[rd] = get_unaligned((unsigned short *)eaddr);
+			else
+				put_unaligned(regs->uregs[rd], (unsigned short *)eaddr);
+
+			/* signed half-word? */
+			if (instr & 0x40)
+				regs->uregs[rd] = (long)((short) regs->uregs[rd]);
+
+			if (!LDST_P_BIT(instr)) {
+				if (LDST_U_BIT(instr))
+					eaddr += offset.un;
+				else
+					eaddr -= offset.un;
+				regs->uregs[rn] = eaddr;
+			} else if (LDST_W_BIT(instr))
+				regs->uregs[rn] = eaddr;
+			break;
 		}
-		show_regs (regs);
-		c_backtrace (regs->ARM_fp, regs->ARM_cpsr);
-#endif
-		force_sig(SIGSEGV, tsk);
-		goto out;
-	}
 
-	/* Are we prepared to handle this kernel fault?  */
-	if ((fixup = search_exception_table(instruction_pointer(regs))) != 0) {
-		printk(KERN_DEBUG "%s: Exception at [<%lx>] addr=%lx (fixup: %lx)\n",
-			tsk->comm, regs->ARM_pc, addr, fixup);
-		regs->ARM_pc = fixup;
-		goto out;
+	default:
+		ai_skipped += 1;
+		panic("Alignment trap: not handling instruction %08X at %08lX",
+				instr, regs->ARM_pc - correction - 4);
+		break;
+
+	case 0x04000000:
+		offset.un = OFFSET_BITS(instr);
+		goto ldr_str;
+
+	case 0x06000000:
+		offset.un = regs->uregs[RM_BITS(instr)];
+
+		if (IS_SHIFT(instr)) {
+			unsigned int shiftval = SHIFT_BITS(instr);
+
+			switch(SHIFT_TYPE(instr)) {
+			case SHIFT_LSL:
+				offset.un <<= shiftval;
+				break;
+
+			case SHIFT_LSR:
+				offset.un >>= shiftval;
+				break;
+
+			case SHIFT_ASR:
+				offset.sn >>= shiftval;
+				break;
+
+			case SHIFT_RORRRX:
+				if (shiftval == 0) {
+					offset.un >>= 1;
+					if (regs->ARM_cpsr & CC_C_BIT)
+						offset.un |= 1 << 31;
+				} else
+					offset.un = offset.un >> shiftval |
+							  offset.un << (32 - shiftval);
+				break;
+			}
+		}
+
+	ldr_str:
+		ai_word += 1;
+		if (LDST_P_BIT(instr)) {
+			if (LDST_U_BIT(instr))
+				eaddr += offset.un;
+			else
+				eaddr -= offset.un;
+		} else {
+			if (LDST_W_BIT(instr)) {
+				printk(KERN_ERR "Not handling ldrt/strt correctly\n");
+				return 1;
+			}
+		}
+
+		if (LDST_L_BIT(instr)) {
+			regs->uregs[rd] = get_unaligned((unsigned long *)eaddr);
+			if (rd == 15)
+				correction = 0;
+		} else
+			put_unaligned(regs->uregs[rd], (unsigned long *)eaddr);
+
+		if (!LDST_P_BIT(instr)) {
+			if (LDST_U_BIT(instr))
+				eaddr += offset.un;
+			else
+				eaddr -= offset.un;
+
+			regs->uregs[rn] = eaddr;
+		} else if (LDST_W_BIT(instr))
+			regs->uregs[rn] = eaddr;
+		break;
+
+	case 0x08000000:
+		if (LDM_S_BIT(instr))
+			panic("Alignment trap: not handling LDM with s-bit\n");
+		ai_multi += 1;
+
+		for (regbits = REGMASK_BITS(instr), nr_regs = 0; regbits; regbits >>= 1)
+			nr_regs += 4;
+
+		if  (!LDST_U_BIT(instr))
+			eaddr -= nr_regs;
+
+		if ((LDST_U_BIT(instr) == 0 && LDST_P_BIT(instr) == 0) ||
+		    (LDST_U_BIT(instr)      && LDST_P_BIT(instr)))
+			eaddr += 4;
+
+		for (regbits = REGMASK_BITS(instr), rd = 0; regbits; regbits >>= 1, rd += 1)
+			if (regbits & 1) {
+				if (LDST_L_BIT(instr)) {
+					regs->uregs[rd] = get_unaligned((unsigned long *)eaddr);
+					if (rd == 15)
+						correction = 0;
+				} else
+					put_unaligned(regs->uregs[rd], (unsigned long *)eaddr);
+				eaddr += 4;
+			}
+
+		if (LDST_W_BIT(instr)) {
+			if (LDST_P_BIT(instr) && !LDST_U_BIT(instr))
+				eaddr -= nr_regs;
+			else if (LDST_P_BIT(instr))
+				eaddr -= 4;
+			else if (!LDST_U_BIT(instr))
+				eaddr -= 4 + nr_regs;
+			regs->uregs[rn] = eaddr;
+		}
+		break;
 	}
 
-	kernel_page_fault (addr, mode, regs, tsk, mm);
-out:
-	unlock_kernel();
+	regs->ARM_pc -= correction;
+
+	return 0;
 }
 
-/*
- * Handle a data abort.  Note that we have to handle a range of addresses
- * on ARM2/3 for ldm.  If both pages are zero-mapped, then we have to force
- * a copy-on-write
- */
+#endif
+
 asmlinkage void
-do_DataAbort (unsigned long addr, int fsr, int error_code, struct pt_regs *regs)
+do_DataAbort(unsigned long addr, int fsr, int error_code, struct pt_regs *regs)
 {
 	if (user_mode(regs))
 		error_code |= FAULT_CODE_USER;
+
 #define DIE(signr,nam)\
 		force_sig(signr, current);\
-		die_if_kernel(nam, regs, fsr, signr);\
-		break;
+		die(nam, regs, fsr);\
+		do_exit(signr);\
+		break
 
 	switch (fsr & 15) {
-	case 2:
-		DIE(SIGKILL, "Terminal exception")
+	/*
+	 *  0 - vector exception
+	 */
 	case 0:
-		DIE(SIGSEGV, "Vector exception")
+		force_sig(SIGSEGV, current);
+		if (!user_mode(regs)) {
+			die("vector exception", regs, fsr);
+			do_exit(SIGSEGV);
+		}
+		break;
+
+	/*
+	 * 15 - permission fault on page
+	 *  5 - page-table entry descriptor fault
+	 *  7 - first-level descriptor fault
+	 */
+	case 15: case 5: case 7:
+		do_page_fault(addr, error_code, regs);
+		break;
+
+	/*
+	 * 13 - permission fault on section
+	 */
+	case 13:
+		force_sig(SIGSEGV, current);
+		if (!user_mode(regs)) {
+			die("section permission fault", regs, fsr);
+			do_exit(SIGSEGV);
+		} else {
+#ifdef CONFIG_DEBUG_USER
+			printk("%s: permission fault on section, "
+			       "address=0x%08lx, code %d\n",
+			       current->comm, addr, error_code);
+#ifdef DEBUG
+			{
+				unsigned int i, j;
+				unsigned long *sp;
+
+				sp = (unsigned long *) (regs->ARM_sp - 128);
+				for (j = 0; j < 20 && sp_valid(sp); j++) {
+					printk("%p: ", sp);
+					for (i = 0; i < 8 && sp_valid(sp); i += 1, sp++)
+						printk("%08lx ", *sp);
+					printk("\n");
+				}
+				show_regs(regs);
+				c_backtrace(regs->ARM_fp, regs->ARM_cpsr);
+			}
+#endif
+#endif
+		}
+		break;
+
 	case 1:
 	case 3:
-		DIE(SIGBUS, "Alignment exception")
+#ifdef CONFIG_ALIGNMENT_TRAP
+		if (!do_alignment_exception(regs))
+			break;
+#endif
+		/*
+		 * this should never happen
+		 */
+		DIE(SIGBUS, "Alignment exception");
+		break;
+
+	case 2:
+		DIE(SIGKILL, "Terminal exception");
 	case 12:
 	case 14:
-		DIE(SIGBUS, "External abort on translation")
+		DIE(SIGBUS, "External abort on translation");
 	case 9:
 	case 11:
-		DIE(SIGSEGV, "Domain fault")
-	case 13:/* permission fault on section */
-#ifdef DEBUG
-		{
-			unsigned int i, j;
-			unsigned long *sp;
-
-			printk ("%s: section permission fault (bad address=0x%08lx, code %d)\n",
-				current->comm, addr, error_code);
-			sp = (unsigned long *) (regs->ARM_sp - 128);
-			for (j = 0; j < 20 && sp_valid (sp); j++) {
-				printk ("%p: ", sp);
-				for (i = 0; i < 8 && sp_valid (sp); i += 1, sp++)
-					printk ("%08lx ", *sp);
-				printk ("\n");
-			}
-			show_regs (regs);
-			c_backtrace(regs->ARM_fp, regs->ARM_cpsr);
-		}
-#endif
-		DIE(SIGSEGV, "Permission fault")
+		DIE(SIGSEGV, "Domain fault");
 
-	case 15:/* permission fault on page */
-	case 5:	/* page-table entry descriptor fault */
-	case 7:	/* first-level descriptor fault */
-		page_fault (addr, error_code, regs);
-		break;
 	case 4:
 	case 6:
-		DIE(SIGBUS, "External abort on linefetch")
+		DIE(SIGBUS, "External abort on linefetch");
 	case 8:
 	case 10:
-		DIE(SIGBUS, "External abort on non-linefetch")
+		DIE(SIGBUS, "External abort on non-linefetch");
 	}
 }
 
 asmlinkage int
-do_PrefetchAbort (unsigned long addr, struct pt_regs *regs)
+do_PrefetchAbort(unsigned long addr, struct pt_regs *regs)
 {
-#if 0
-	/* does this still apply ? */
-	if (the memc mapping for this page exists - can check now...) {
-		printk ("Page in, but got abort (undefined instruction?)\n");
-		return 0;
-	}
-#endif
-	page_fault (addr, FAULT_CODE_USER|FAULT_CODE_READ, regs);
+	do_page_fault(addr, FAULT_CODE_USER|FAULT_CODE_READ, regs);
 	return 1;
 }
-