sparc32: switch to generic extables

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

arch/sparc/include/asm/elf_64.h

@@ -8,7 +8,6 @@
 
 #include <asm/ptrace.h>
 #include <asm/processor.h>
-#include <asm/extable_64.h>
 #include <asm/spitfire.h>
 #include <asm/adi.h>
 

arch/sparc/include/asm/extable.h

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: GPL-2.0 */
-#ifndef __ASM_EXTABLE64_H
+#ifndef __ASM_EXTABLE_H
-#define __ASM_EXTABLE64_H
+#define __ASM_EXTABLE_H
 /*
  * The exception table consists of pairs of addresses: the first is the
  * address of an instruction that is allowed to fault, and the second is

arch/sparc/include/asm/uaccess.h

@@ -1,6 +1,9 @@
 /* SPDX-License-Identifier: GPL-2.0 */
 #ifndef ___ASM_SPARC_UACCESS_H
 #define ___ASM_SPARC_UACCESS_H
+
+#include <asm/extable.h>
+
 #if defined(__sparc__) && defined(__arch64__)
 #include <asm/uaccess_64.h>
 #else

arch/sparc/include/asm/uaccess_32.h

@@ -13,9 +13,6 @@
 
 #include <asm/processor.h>
 
-#define ARCH_HAS_SORT_EXTABLE
-#define ARCH_HAS_SEARCH_EXTABLE
-
 /* Sparc is not segmented, however we need to be able to fool access_ok()
  * when doing system calls from kernel mode legitimately.
  *
@@ -40,36 +37,6 @@
 #define __access_ok(addr, size) (__user_ok((addr) & get_fs().seg, (size)))
 #define access_ok(addr, size) __access_ok((unsigned long)(addr), size)
 
-/*
- * The exception table consists of pairs of addresses: the first is the
- * address of an instruction that is allowed to fault, and the second is
- * the address at which the program should continue.  No registers are
- * modified, so it is entirely up to the continuation code to figure out
- * what to do.
- *
- * All the routines below use bits of fixup code that are out of line
- * with the main instruction path.  This means when everything is well,
- * we don't even have to jump over them.  Further, they do not intrude
- * on our cache or tlb entries.
- *
- * There is a special way how to put a range of potentially faulting
- * insns (like twenty ldd/std's with now intervening other instructions)
- * You specify address of first in insn and 0 in fixup and in the next
- * exception_table_entry you specify last potentially faulting insn + 1
- * and in fixup the routine which should handle the fault.
- * That fixup code will get
- * (faulting_insn_address - first_insn_in_the_range_address)/4
- * in %g2 (ie. index of the faulting instruction in the range).
- */
-
-struct exception_table_entry
-{
-        unsigned long insn, fixup;
-};
-
-/* Returns 0 if exception not found and fixup otherwise.  */
-unsigned long search_extables_range(unsigned long addr, unsigned long *g2);
-
 /* Uh, these should become the main single-value transfer routines..
  * They automatically use the right size if we just have the right
  * pointer type..

arch/sparc/include/asm/uaccess_64.h

@@ -10,7 +10,6 @@
 #include <linux/string.h>
 #include <asm/asi.h>
 #include <asm/spitfire.h>
-#include <asm/extable_64.h>
 
 #include <asm/processor.h>
 

arch/sparc/kernel/unaligned_32.c

@@ -16,6 +16,7 @@
 #include <linux/uaccess.h>
 #include <linux/smp.h>
 #include <linux/perf_event.h>
+#include <linux/extable.h>
 
 #include <asm/setup.h>
 
@@ -213,10 +214,10 @@ static inline int ok_for_kernel(unsigned int insn)
 
 static void kernel_mna_trap_fault(struct pt_regs *regs, unsigned int insn)
 {
-	unsigned long g2 = regs->u_regs [UREG_G2];
+	const struct exception_table_entry *entry;
-	unsigned long fixup = search_extables_range(regs->pc, &g2);
 
-	if (!fixup) {
+	entry = search_exception_tables(regs->pc);
+	if (!entry) {
 		unsigned long address = compute_effective_address(regs, insn);
         	if(address < PAGE_SIZE) {
                 	printk(KERN_ALERT "Unable to handle kernel NULL pointer dereference in mna handler");
@@ -232,9 +233,8 @@ static void kernel_mna_trap_fault(struct pt_regs *regs, unsigned int insn)
 	        die_if_kernel("Oops", regs);
 		/* Not reached */
 	}
-	regs->pc = fixup;
+	regs->pc = entry->fixup;
 	regs->npc = regs->pc + 4;
-	regs->u_regs [UREG_G2] = g2;
 }
 
 asmlinkage void kernel_unaligned_trap(struct pt_regs *regs, unsigned int insn)

arch/sparc/mm/Makefile

@@ -8,7 +8,7 @@ ccflags-y := -Werror
 obj-$(CONFIG_SPARC64)   += ultra.o tlb.o tsb.o
 obj-y                   += fault_$(BITS).o
 obj-y                   += init_$(BITS).o
-obj-$(CONFIG_SPARC32)   += extable.o srmmu.o iommu.o io-unit.o
+obj-$(CONFIG_SPARC32)   += srmmu.o iommu.o io-unit.o
 obj-$(CONFIG_SPARC32)   += srmmu_access.o
 obj-$(CONFIG_SPARC32)   += hypersparc.o viking.o tsunami.o swift.o
 obj-$(CONFIG_SPARC32)   += leon_mm.o

arch/sparc/mm/extable.c

@@ -1,107 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-/*
- * linux/arch/sparc/mm/extable.c
- */
-
-#include <linux/module.h>
-#include <linux/extable.h>
-#include <linux/uaccess.h>
-
-void sort_extable(struct exception_table_entry *start,
-		  struct exception_table_entry *finish)
-{
-}
-
-/* Caller knows they are in a range if ret->fixup == 0 */
-const struct exception_table_entry *
-search_extable(const struct exception_table_entry *base,
-	       const size_t num,
-	       unsigned long value)
-{
-	int i;
-
-	/* Single insn entries are encoded as:
-	 *	word 1:	insn address
-	 *	word 2:	fixup code address
-	 *
-	 * Range entries are encoded as:
-	 *	word 1: first insn address
-	 *	word 2: 0
-	 *	word 3: last insn address + 4 bytes
-	 *	word 4: fixup code address
-	 *
-	 * Deleted entries are encoded as:
-	 *	word 1: unused
-	 *	word 2: -1
-	 *
-	 * See asm/uaccess.h for more details.
-	 */
-
-	/* 1. Try to find an exact match. */
-	for (i = 0; i < num; i++) {
-		if (base[i].fixup == 0) {
-			/* A range entry, skip both parts. */
-			i++;
-			continue;
-		}
-
-		/* A deleted entry; see trim_init_extable */
-		if (base[i].fixup == -1)
-			continue;
-
-		if (base[i].insn == value)
-			return &base[i];
-	}
-
-	/* 2. Try to find a range match. */
-	for (i = 0; i < (num - 1); i++) {
-		if (base[i].fixup)
-			continue;
-
-		if (base[i].insn <= value && base[i + 1].insn > value)
-			return &base[i];
-
-		i++;
-	}
-
-        return NULL;
-}
-
-#ifdef CONFIG_MODULES
-/* We could memmove them around; easier to mark the trimmed ones. */
-void trim_init_extable(struct module *m)
-{
-	unsigned int i;
-	bool range;
-
-	for (i = 0; i < m->num_exentries; i += range ? 2 : 1) {
-		range = m->extable[i].fixup == 0;
-
-		if (within_module_init(m->extable[i].insn, m)) {
-			m->extable[i].fixup = -1;
-			if (range)
-				m->extable[i+1].fixup = -1;
-		}
-		if (range)
-			i++;
-	}
-}
-#endif /* CONFIG_MODULES */
-
-/* Special extable search, which handles ranges.  Returns fixup */
-unsigned long search_extables_range(unsigned long addr, unsigned long *g2)
-{
-	const struct exception_table_entry *entry;
-
-	entry = search_exception_tables(addr);
-	if (!entry)
-		return 0;
-
-	/* Inside range?  Fix g2 and return correct fixup */
-	if (!entry->fixup) {
-		*g2 = (addr - entry->insn) / 4;
-		return (entry + 1)->fixup;
-	}
-
-	return entry->fixup;
-}

arch/sparc/mm/fault_32.c

@@ -23,6 +23,7 @@
 #include <linux/interrupt.h>
 #include <linux/kdebug.h>
 #include <linux/uaccess.h>
+#include <linux/extable.h>
 
 #include <asm/page.h>
 #include <asm/openprom.h>
@@ -114,8 +115,6 @@ asmlinkage void do_sparc_fault(struct pt_regs *regs, int text_fault, int write,
 	struct vm_area_struct *vma;
 	struct task_struct *tsk = current;
 	struct mm_struct *mm = tsk->mm;
-	unsigned int fixup;
-	unsigned long g2;
 	int from_user = !(regs->psr & PSR_PS);
 	int code;
 	vm_fault_t fault;
@@ -233,23 +232,20 @@ asmlinkage void do_sparc_fault(struct pt_regs *regs, int text_fault, int write,
 
 	/* Is this in ex_table? */
 no_context:
-	g2 = regs->u_regs[UREG_G2];
 	if (!from_user) {
-		fixup = search_extables_range(regs->pc, &g2);
+		const struct exception_table_entry *entry;
-		/* Values below 10 are reserved for other things */
+
-		if (fixup > 10) {
+		entry = search_exception_tables(regs->pc);
 #ifdef DEBUG_EXCEPTIONS
 		printk("Exception: PC<%08lx> faddr<%08lx>\n",
 		       regs->pc, address);
-			printk("EX_TABLE: insn<%08lx> fixup<%08x> g2<%08lx>\n",
+		printk("EX_TABLE: insn<%08lx> fixup<%08x>\n",
-				regs->pc, fixup, g2);
+			regs->pc, entry->fixup);
 #endif
-			regs->u_regs[UREG_G2] = g2;
+		regs->pc = entry->fixup;
-			regs->pc = fixup;
 		regs->npc = regs->pc + 4;
 		return;
 	}
-	}
 
 	unhandled_fault(address, tsk, regs);
 	do_exit(SIGKILL);

lib/extable.c

@@ -21,7 +21,6 @@ static inline unsigned long ex_to_insn(const struct exception_table_entry *x)
 }
 #endif
 
-#ifndef ARCH_HAS_SORT_EXTABLE
 #ifndef ARCH_HAS_RELATIVE_EXTABLE
 #define swap_ex		NULL
 #else
@@ -88,9 +87,6 @@ void trim_init_extable(struct module *m)
 		m->num_exentries--;
 }
 #endif /* CONFIG_MODULES */
-#endif /* !ARCH_HAS_SORT_EXTABLE */
-
-#ifndef ARCH_HAS_SEARCH_EXTABLE
 
 static int cmp_ex_search(const void *key, const void *elt)
 {
@@ -120,4 +116,3 @@ search_extable(const struct exception_table_entry *base,
 	return bsearch(&value, base, num,
 		       sizeof(struct exception_table_entry), cmp_ex_search);
 }
-#endif