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sparc32: switch to generic extables

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Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2020-07-16 14:05:36 -04:00
parent c4da8e0dc6
commit b4edf06c8a
10 changed files with 22 additions and 170 deletions
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1
arch/sparc/include/asm/elf_64.h
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@ -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>

4
arch/sparc/include/asm/extable_64.h → arch/sparc/include/asm/extable.h
View File

@ -1,6 +1,6 @@
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __ASM_EXTABLE64_H
#define __ASM_EXTABLE64_H
#ifndef __ASM_EXTABLE_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

3
arch/sparc/include/asm/uaccess.h
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@ -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

33
arch/sparc/include/asm/uaccess_32.h
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@ -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..

1
arch/sparc/include/asm/uaccess_64.h
View File

@ -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>

10
arch/sparc/kernel/unaligned_32.c
View File

@ -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];
unsigned long fixup = search_extables_range(regs->pc, &g2);
const struct exception_table_entry *entry;
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)

2
arch/sparc/mm/Makefile
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@ -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

107
arch/sparc/mm/extable.c
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@ -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;
}

26
arch/sparc/mm/fault_32.c
View File

@ -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;
@ -233,22 +232,19 @@ 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);
/* Values below 10 are reserved for other things */
if (fixup > 10) {
const struct exception_table_entry *entry;
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",
regs->pc, fixup, g2);
printk("Exception: PC<%08lx> faddr<%08lx>\n",
regs->pc, address);
printk("EX_TABLE: insn<%08lx> fixup<%08x>\n",
regs->pc, entry->fixup);
#endif
regs->u_regs[UREG_G2] = g2;
regs->pc = fixup;
regs->npc = regs->pc + 4;
return;
}
regs->pc = entry->fixup;
regs->npc = regs->pc + 4;
return;
}
unhandled_fault(address, tsk, regs);

5
lib/extable.c
View File

@ -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