diff options
Diffstat (limited to 'arch/arm/kernel/swp_emulate.c')
| -rw-r--r-- | arch/arm/kernel/swp_emulate.c | 77 |
1 files changed, 28 insertions, 49 deletions
diff --git a/arch/arm/kernel/swp_emulate.c b/arch/arm/kernel/swp_emulate.c index b1b89882b113..fdce83c95acb 100644 --- a/arch/arm/kernel/swp_emulate.c +++ b/arch/arm/kernel/swp_emulate.c @@ -1,13 +1,10 @@ +// SPDX-License-Identifier: GPL-2.0-only /* * linux/arch/arm/kernel/swp_emulate.c * * Copyright (C) 2009 ARM Limited * __user_* functions adapted from include/asm/uaccess.h * - * This program is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License version 2 as - * published by the Free Software Foundation. - * * Implements emulation of the SWP/SWPB instructions using load-exclusive and * store-exclusive for processors that have them disabled (or future ones that * might not implement them). @@ -23,25 +20,28 @@ #include <linux/proc_fs.h> #include <linux/seq_file.h> #include <linux/sched.h> +#include <linux/sched/mm.h> #include <linux/syscalls.h> #include <linux/perf_event.h> #include <asm/opcodes.h> +#include <asm/system_info.h> #include <asm/traps.h> -#include <asm/uaccess.h> +#include <linux/uaccess.h> /* * Error-checking SWP macros implemented using ldrex{b}/strex{b} */ #define __user_swpX_asm(data, addr, res, temp, B) \ __asm__ __volatile__( \ - " mov %2, %1\n" \ - "0: ldrex"B" %1, [%3]\n" \ - "1: strex"B" %0, %2, [%3]\n" \ + ".arch armv7-a\n" \ + "0: ldrex"B" %2, [%3]\n" \ + "1: strex"B" %0, %1, [%3]\n" \ " cmp %0, #0\n" \ + " moveq %1, %2\n" \ " movne %0, %4\n" \ "2:\n" \ - " .section .fixup,\"ax\"\n" \ + " .section .text.fixup,\"ax\"\n" \ " .align 2\n" \ "3: mov %0, %5\n" \ " b 2b\n" \ @@ -89,18 +89,6 @@ static int proc_status_show(struct seq_file *m, void *v) seq_printf(m, "Last process:\t\t%d\n", previous_pid); return 0; } - -static int proc_status_open(struct inode *inode, struct file *file) -{ - return single_open(file, proc_status_show, PDE_DATA(inode)); -} - -static const struct file_operations proc_status_fops = { - .open = proc_status_open, - .read = seq_read, - .llseek = seq_lseek, - .release = single_release, -}; #endif /* @@ -108,21 +96,20 @@ static const struct file_operations proc_status_fops = { */ static void set_segfault(struct pt_regs *regs, unsigned long addr) { - siginfo_t info; + int si_code; - down_read(¤t->mm->mmap_sem); + mmap_read_lock(current->mm); if (find_vma(current->mm, addr) == NULL) - info.si_code = SEGV_MAPERR; + si_code = SEGV_MAPERR; else - info.si_code = SEGV_ACCERR; - up_read(¤t->mm->mmap_sem); - - info.si_signo = SIGSEGV; - info.si_errno = 0; - info.si_addr = (void *) instruction_pointer(regs); + si_code = SEGV_ACCERR; + mmap_read_unlock(current->mm); pr_debug("SWP{B} emulation: access caused memory abort!\n"); - arm_notify_die("Illegal memory access", regs, &info, 0, 0); + arm_notify_die("Illegal memory access", regs, + SIGSEGV, si_code, + (void __user *)instruction_pointer(regs), + 0, 0); abtcounter++; } @@ -140,19 +127,14 @@ static int emulate_swpX(unsigned int address, unsigned int *data, while (1) { unsigned long temp; + unsigned int __ua_flags; - /* - * Barrier required between accessing protected resource and - * releasing a lock for it. Legacy code might not have done - * this, and we cannot determine that this is not the case - * being emulated, so insert always. - */ - smp_mb(); - + __ua_flags = uaccess_save_and_enable(); if (type == TYPE_SWPB) __user_swpb_asm(*data, address, res, temp); else __user_swp_asm(*data, address, res, temp); + uaccess_restore(__ua_flags); if (likely(res != -EAGAIN) || signal_pending(current)) break; @@ -161,13 +143,6 @@ static int emulate_swpX(unsigned int address, unsigned int *data, } if (res == 0) { - /* - * Barrier also required between acquiring a lock for a - * protected resource and accessing the resource. Inserted for - * same reason as above. - */ - smp_mb(); - if (type == TYPE_SWPB) swpbcounter++; else @@ -221,7 +196,7 @@ static int swp_handler(struct pt_regs *regs, unsigned int instr) destreg, EXTRACT_REG_NUM(instr, RT2_OFFSET), data); /* Check access in reasonable access range for both SWP and SWPB */ - if (!access_ok(VERIFY_WRITE, (address & ~3), 4)) { + if (!access_ok((void __user *)(address & ~3), 4)) { pr_debug("SWP{B} emulation: access to %p not allowed!\n", (void *)address); res = -EFAULT; @@ -266,12 +241,16 @@ static struct undef_hook swp_hook = { */ static int __init swp_emulation_init(void) { + if (cpu_architecture() < CPU_ARCH_ARMv7) + return 0; + #ifdef CONFIG_PROC_FS - if (!proc_create("cpu/swp_emulation", S_IRUGO, NULL, &proc_status_fops)) + if (!proc_create_single("cpu/swp_emulation", S_IRUGO, NULL, + proc_status_show)) return -ENOMEM; #endif /* CONFIG_PROC_FS */ - printk(KERN_NOTICE "Registering SWP/SWPB emulation handler\n"); + pr_notice("Registering SWP/SWPB emulation handler\n"); register_undef_hook(&swp_hook); return 0; |