diff options
Diffstat (limited to 'ANDROID_3.4.5/arch/arm/kernel/swp_emulate.c')
| -rw-r--r-- | ANDROID_3.4.5/arch/arm/kernel/swp_emulate.c | 283 |
1 files changed, 0 insertions, 283 deletions
diff --git a/ANDROID_3.4.5/arch/arm/kernel/swp_emulate.c b/ANDROID_3.4.5/arch/arm/kernel/swp_emulate.c deleted file mode 100644 index df745188..00000000 --- a/ANDROID_3.4.5/arch/arm/kernel/swp_emulate.c +++ /dev/null @@ -1,283 +0,0 @@ -/* - * 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). - * - * Syntax of SWP{B} instruction: SWP{B}<c> <Rt>, <Rt2>, [<Rn>] - * Where: Rt = destination - * Rt2 = source - * Rn = address - */ - -#include <linux/init.h> -#include <linux/kernel.h> -#include <linux/proc_fs.h> -#include <linux/sched.h> -#include <linux/syscalls.h> -#include <linux/perf_event.h> - -#include <asm/opcodes.h> -#include <asm/traps.h> -#include <asm/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" \ - " cmp %0, #0\n" \ - " movne %0, %4\n" \ - "2:\n" \ - " .section .fixup,\"ax\"\n" \ - " .align 2\n" \ - "3: mov %0, %5\n" \ - " b 2b\n" \ - " .previous\n" \ - " .section __ex_table,\"a\"\n" \ - " .align 3\n" \ - " .long 0b, 3b\n" \ - " .long 1b, 3b\n" \ - " .previous" \ - : "=&r" (res), "+r" (data), "=&r" (temp) \ - : "r" (addr), "i" (-EAGAIN), "i" (-EFAULT) \ - : "cc", "memory") - -#define __user_swp_asm(data, addr, res, temp) \ - __user_swpX_asm(data, addr, res, temp, "") -#define __user_swpb_asm(data, addr, res, temp) \ - __user_swpX_asm(data, addr, res, temp, "b") - -/* - * Macros/defines for extracting register numbers from instruction. - */ -#define EXTRACT_REG_NUM(instruction, offset) \ - (((instruction) & (0xf << (offset))) >> (offset)) -#define RN_OFFSET 16 -#define RT_OFFSET 12 -#define RT2_OFFSET 0 -/* - * Bit 22 of the instruction encoding distinguishes between - * the SWP and SWPB variants (bit set means SWPB). - */ -#define TYPE_SWPB (1 << 22) - -static unsigned long swpcounter; -static unsigned long swpbcounter; -static unsigned long abtcounter; -static pid_t previous_pid; - -#ifdef CONFIG_PROC_FS -static int proc_read_status(char *page, char **start, off_t off, int count, - int *eof, void *data) -{ - char *p = page; - int len; - - p += sprintf(p, "Emulated SWP:\t\t%lu\n", swpcounter); - p += sprintf(p, "Emulated SWPB:\t\t%lu\n", swpbcounter); - p += sprintf(p, "Aborted SWP{B}:\t\t%lu\n", abtcounter); - if (previous_pid != 0) - p += sprintf(p, "Last process:\t\t%d\n", previous_pid); - - len = (p - page) - off; - if (len < 0) - len = 0; - - *eof = (len <= count) ? 1 : 0; - *start = page + off; - - return len; -} -#endif - -/* - * Set up process info to signal segmentation fault - called on access error. - */ -static void set_segfault(struct pt_regs *regs, unsigned long addr) -{ - siginfo_t info; - - if (find_vma(current->mm, addr) == NULL) - info.si_code = SEGV_MAPERR; - else - info.si_code = SEGV_ACCERR; - - info.si_signo = SIGSEGV; - info.si_errno = 0; - info.si_addr = (void *) instruction_pointer(regs); - - pr_debug("SWP{B} emulation: access caused memory abort!\n"); - arm_notify_die("Illegal memory access", regs, &info, 0, 0); - - abtcounter++; -} - -static int emulate_swpX(unsigned int address, unsigned int *data, - unsigned int type) -{ - unsigned int res = 0; - - if ((type != TYPE_SWPB) && (address & 0x3)) { - /* SWP to unaligned address not permitted */ - pr_debug("SWP instruction on unaligned pointer!\n"); - return -EFAULT; - } - - while (1) { - unsigned long temp; - - /* - * 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(); - - if (type == TYPE_SWPB) - __user_swpb_asm(*data, address, res, temp); - else - __user_swp_asm(*data, address, res, temp); - - if (likely(res != -EAGAIN) || signal_pending(current)) - break; - - cond_resched(); - } - - 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 - swpcounter++; - } - - return res; -} - -/* - * swp_handler logs the id of calling process, dissects the instruction, sanity - * checks the memory location, calls emulate_swpX for the actual operation and - * deals with fixup/error handling before returning - */ -static int swp_handler(struct pt_regs *regs, unsigned int instr) -{ - unsigned int address, destreg, data, type; - unsigned int res = 0; - - perf_sw_event(PERF_COUNT_SW_EMULATION_FAULTS, 1, regs, regs->ARM_pc); - - res = arm_check_condition(instr, regs->ARM_cpsr); - switch (res) { - case ARM_OPCODE_CONDTEST_PASS: - break; - case ARM_OPCODE_CONDTEST_FAIL: - /* Condition failed - return to next instruction */ - regs->ARM_pc += 4; - return 0; - case ARM_OPCODE_CONDTEST_UNCOND: - /* If unconditional encoding - not a SWP, undef */ - return -EFAULT; - default: - return -EINVAL; - } - - if (current->pid != previous_pid) { - pr_debug("\"%s\" (%ld) uses deprecated SWP{B} instruction\n", - current->comm, (unsigned long)current->pid); - previous_pid = current->pid; - } - - address = regs->uregs[EXTRACT_REG_NUM(instr, RN_OFFSET)]; - data = regs->uregs[EXTRACT_REG_NUM(instr, RT2_OFFSET)]; - destreg = EXTRACT_REG_NUM(instr, RT_OFFSET); - - type = instr & TYPE_SWPB; - - pr_debug("addr in r%d->0x%08x, dest is r%d, source in r%d->0x%08x)\n", - EXTRACT_REG_NUM(instr, RN_OFFSET), address, - 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)) { - pr_debug("SWP{B} emulation: access to %p not allowed!\n", - (void *)address); - res = -EFAULT; - } else { - res = emulate_swpX(address, &data, type); - } - - if (res == 0) { - /* - * On successful emulation, revert the adjustment to the PC - * made in kernel/traps.c in order to resume execution at the - * instruction following the SWP{B}. - */ - regs->ARM_pc += 4; - regs->uregs[destreg] = data; - } else if (res == -EFAULT) { - /* - * Memory errors do not mean emulation failed. - * Set up signal info to return SEGV, then return OK - */ - set_segfault(regs, address); - } - - return 0; -} - -/* - * Only emulate SWP/SWPB executed in ARM state/User mode. - * The kernel must be SWP free and SWP{B} does not exist in Thumb/ThumbEE. - */ -static struct undef_hook swp_hook = { - .instr_mask = 0x0fb00ff0, - .instr_val = 0x01000090, - .cpsr_mask = MODE_MASK | PSR_T_BIT | PSR_J_BIT, - .cpsr_val = USR_MODE, - .fn = swp_handler -}; - -/* - * Register handler and create status file in /proc/cpu - * Invoked as late_initcall, since not needed before init spawned. - */ -static int __init swp_emulation_init(void) -{ -#ifdef CONFIG_PROC_FS - struct proc_dir_entry *res; - - res = create_proc_entry("cpu/swp_emulation", S_IRUGO, NULL); - - if (!res) - return -ENOMEM; - - res->read_proc = proc_read_status; -#endif /* CONFIG_PROC_FS */ - - printk(KERN_NOTICE "Registering SWP/SWPB emulation handler\n"); - register_undef_hook(&swp_hook); - - return 0; -} - -late_initcall(swp_emulation_init); |