ed3a06b10a
Perform the cleanup in the FIXME comment in common_semi_gdb_syscall. Do not modify guest registers until the syscall is complete, which in the gdbstub case is asynchronous. In the synchronous non-gdbstub case, use common_semi_set_ret to set the result. Merge set_swi_errno into common_semi_cb. Rely on the latter for combined return value / errno setting. Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
538 lines
17 KiB
C
538 lines
17 KiB
C
/*
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* qemu user cpu loop
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*
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* Copyright (c) 2003-2008 Fabrice Bellard
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, see <http://www.gnu.org/licenses/>.
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*/
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#include "qemu/osdep.h"
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#include "qemu.h"
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#include "user-internals.h"
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#include "elf.h"
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#include "cpu_loop-common.h"
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#include "signal-common.h"
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#include "semihosting/common-semi.h"
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#include "target/arm/syndrome.h"
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#define get_user_code_u32(x, gaddr, env) \
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({ abi_long __r = get_user_u32((x), (gaddr)); \
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if (!__r && bswap_code(arm_sctlr_b(env))) { \
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(x) = bswap32(x); \
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} \
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__r; \
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})
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#define get_user_code_u16(x, gaddr, env) \
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({ abi_long __r = get_user_u16((x), (gaddr)); \
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if (!__r && bswap_code(arm_sctlr_b(env))) { \
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(x) = bswap16(x); \
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} \
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__r; \
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})
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#define get_user_data_u32(x, gaddr, env) \
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({ abi_long __r = get_user_u32((x), (gaddr)); \
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if (!__r && arm_cpu_bswap_data(env)) { \
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(x) = bswap32(x); \
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} \
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__r; \
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})
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#define get_user_data_u16(x, gaddr, env) \
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({ abi_long __r = get_user_u16((x), (gaddr)); \
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if (!__r && arm_cpu_bswap_data(env)) { \
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(x) = bswap16(x); \
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} \
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__r; \
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})
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#define put_user_data_u32(x, gaddr, env) \
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({ typeof(x) __x = (x); \
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if (arm_cpu_bswap_data(env)) { \
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__x = bswap32(__x); \
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} \
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put_user_u32(__x, (gaddr)); \
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})
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#define put_user_data_u16(x, gaddr, env) \
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({ typeof(x) __x = (x); \
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if (arm_cpu_bswap_data(env)) { \
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__x = bswap16(__x); \
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} \
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put_user_u16(__x, (gaddr)); \
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})
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/*
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* Similar to code in accel/tcg/user-exec.c, but outside the execution loop.
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* Must be called with mmap_lock.
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* We get the PC of the entry address - which is as good as anything,
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* on a real kernel what you get depends on which mode it uses.
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*/
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static void *atomic_mmu_lookup(CPUArchState *env, uint32_t addr, int size)
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{
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int need_flags = PAGE_READ | PAGE_WRITE_ORG | PAGE_VALID;
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int page_flags;
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/* Enforce guest required alignment. */
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if (unlikely(addr & (size - 1))) {
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force_sig_fault(TARGET_SIGBUS, TARGET_BUS_ADRALN, addr);
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return NULL;
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}
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page_flags = page_get_flags(addr);
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if (unlikely((page_flags & need_flags) != need_flags)) {
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force_sig_fault(TARGET_SIGSEGV,
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page_flags & PAGE_VALID ?
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TARGET_SEGV_ACCERR : TARGET_SEGV_MAPERR, addr);
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return NULL;
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}
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return g2h(env_cpu(env), addr);
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}
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/*
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* See the Linux kernel's Documentation/arm/kernel_user_helpers.rst
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* Input:
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* r0 = oldval
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* r1 = newval
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* r2 = pointer to target value
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*
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* Output:
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* r0 = 0 if *ptr was changed, non-0 if no exchange happened
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* C set if *ptr was changed, clear if no exchange happened
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*/
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static void arm_kernel_cmpxchg32_helper(CPUARMState *env)
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{
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uint32_t oldval, newval, val, addr, cpsr, *host_addr;
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oldval = env->regs[0];
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newval = env->regs[1];
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addr = env->regs[2];
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mmap_lock();
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host_addr = atomic_mmu_lookup(env, addr, 4);
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if (!host_addr) {
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mmap_unlock();
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return;
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}
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val = qatomic_cmpxchg__nocheck(host_addr, oldval, newval);
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mmap_unlock();
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cpsr = (val == oldval) * CPSR_C;
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cpsr_write(env, cpsr, CPSR_C, CPSRWriteByInstr);
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env->regs[0] = cpsr ? 0 : -1;
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}
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/*
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* See the Linux kernel's Documentation/arm/kernel_user_helpers.rst
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* Input:
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* r0 = pointer to oldval
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* r1 = pointer to newval
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* r2 = pointer to target value
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*
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* Output:
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* r0 = 0 if *ptr was changed, non-0 if no exchange happened
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* C set if *ptr was changed, clear if no exchange happened
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*
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* Note segv's in kernel helpers are a bit tricky, we can set the
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* data address sensibly but the PC address is just the entry point.
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*/
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static void arm_kernel_cmpxchg64_helper(CPUARMState *env)
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{
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uint64_t oldval, newval, val;
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uint32_t addr, cpsr;
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uint64_t *host_addr;
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addr = env->regs[0];
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if (get_user_u64(oldval, addr)) {
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goto segv;
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}
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addr = env->regs[1];
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if (get_user_u64(newval, addr)) {
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goto segv;
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}
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mmap_lock();
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addr = env->regs[2];
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host_addr = atomic_mmu_lookup(env, addr, 8);
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if (!host_addr) {
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mmap_unlock();
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return;
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}
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#ifdef CONFIG_ATOMIC64
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val = qatomic_cmpxchg__nocheck(host_addr, oldval, newval);
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cpsr = (val == oldval) * CPSR_C;
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#else
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/*
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* This only works between threads, not between processes, but since
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* the host has no 64-bit cmpxchg, it is the best that we can do.
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*/
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start_exclusive();
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val = *host_addr;
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if (val == oldval) {
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*host_addr = newval;
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cpsr = CPSR_C;
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} else {
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cpsr = 0;
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}
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end_exclusive();
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#endif
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mmap_unlock();
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cpsr_write(env, cpsr, CPSR_C, CPSRWriteByInstr);
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env->regs[0] = cpsr ? 0 : -1;
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return;
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segv:
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force_sig_fault(TARGET_SIGSEGV,
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page_get_flags(addr) & PAGE_VALID ?
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TARGET_SEGV_ACCERR : TARGET_SEGV_MAPERR, addr);
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}
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/* Handle a jump to the kernel code page. */
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static int
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do_kernel_trap(CPUARMState *env)
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{
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uint32_t addr;
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switch (env->regs[15]) {
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case 0xffff0fa0: /* __kernel_memory_barrier */
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smp_mb();
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break;
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case 0xffff0fc0: /* __kernel_cmpxchg */
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arm_kernel_cmpxchg32_helper(env);
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break;
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case 0xffff0fe0: /* __kernel_get_tls */
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env->regs[0] = cpu_get_tls(env);
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break;
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case 0xffff0f60: /* __kernel_cmpxchg64 */
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arm_kernel_cmpxchg64_helper(env);
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break;
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default:
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return 1;
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}
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/* Jump back to the caller. */
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addr = env->regs[14];
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if (addr & 1) {
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env->thumb = true;
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addr &= ~1;
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}
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env->regs[15] = addr;
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return 0;
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}
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static bool insn_is_linux_bkpt(uint32_t opcode, bool is_thumb)
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{
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/*
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* Return true if this insn is one of the three magic UDF insns
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* which the kernel treats as breakpoint insns.
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*/
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if (!is_thumb) {
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return (opcode & 0x0fffffff) == 0x07f001f0;
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} else {
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/*
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* Note that we get the two halves of the 32-bit T32 insn
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* in the opposite order to the value the kernel uses in
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* its undef_hook struct.
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*/
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return ((opcode & 0xffff) == 0xde01) || (opcode == 0xa000f7f0);
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}
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}
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static bool emulate_arm_fpa11(CPUARMState *env, uint32_t opcode)
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{
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TaskState *ts = env_cpu(env)->opaque;
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int rc = EmulateAll(opcode, &ts->fpa, env);
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int raise, enabled;
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if (rc == 0) {
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/* Illegal instruction */
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return false;
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}
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if (rc > 0) {
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/* Everything ok. */
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env->regs[15] += 4;
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return true;
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}
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/* FP exception */
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rc = -rc;
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raise = 0;
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/* Translate softfloat flags to FPSR flags */
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if (rc & float_flag_invalid) {
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raise |= BIT_IOC;
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}
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if (rc & float_flag_divbyzero) {
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raise |= BIT_DZC;
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}
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if (rc & float_flag_overflow) {
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raise |= BIT_OFC;
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}
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if (rc & float_flag_underflow) {
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raise |= BIT_UFC;
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}
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if (rc & float_flag_inexact) {
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raise |= BIT_IXC;
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}
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/* Accumulate unenabled exceptions */
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enabled = ts->fpa.fpsr >> 16;
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ts->fpa.fpsr |= raise & ~enabled;
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if (raise & enabled) {
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/*
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* The kernel's nwfpe emulator does not pass a real si_code.
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* It merely uses send_sig(SIGFPE, current, 1), which results in
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* __send_signal() filling out SI_KERNEL with pid and uid 0 (under
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* the "SEND_SIG_PRIV" case). That's what our force_sig() does.
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*/
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force_sig(TARGET_SIGFPE);
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} else {
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env->regs[15] += 4;
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}
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return true;
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}
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void cpu_loop(CPUARMState *env)
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{
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CPUState *cs = env_cpu(env);
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int trapnr, si_signo, si_code;
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unsigned int n, insn;
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abi_ulong ret;
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for(;;) {
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cpu_exec_start(cs);
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trapnr = cpu_exec(cs);
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cpu_exec_end(cs);
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process_queued_cpu_work(cs);
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switch(trapnr) {
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case EXCP_UDEF:
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case EXCP_NOCP:
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case EXCP_INVSTATE:
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{
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uint32_t opcode;
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/* we handle the FPU emulation here, as Linux */
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/* we get the opcode */
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/* FIXME - what to do if get_user() fails? */
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get_user_code_u32(opcode, env->regs[15], env);
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/*
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* The Linux kernel treats some UDF patterns specially
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* to use as breakpoints (instead of the architectural
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* bkpt insn). These should trigger a SIGTRAP rather
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* than SIGILL.
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*/
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if (insn_is_linux_bkpt(opcode, env->thumb)) {
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goto excp_debug;
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}
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if (!env->thumb && emulate_arm_fpa11(env, opcode)) {
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break;
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}
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force_sig_fault(TARGET_SIGILL, TARGET_ILL_ILLOPN,
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env->regs[15]);
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}
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break;
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case EXCP_SWI:
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{
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env->eabi = 1;
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/* system call */
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if (env->thumb) {
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/* Thumb is always EABI style with syscall number in r7 */
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n = env->regs[7];
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} else {
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/*
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* Equivalent of kernel CONFIG_OABI_COMPAT: read the
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* Arm SVC insn to extract the immediate, which is the
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* syscall number in OABI.
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*/
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/* FIXME - what to do if get_user() fails? */
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get_user_code_u32(insn, env->regs[15] - 4, env);
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n = insn & 0xffffff;
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if (n == 0) {
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/* zero immediate: EABI, syscall number in r7 */
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n = env->regs[7];
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} else {
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/*
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* This XOR matches the kernel code: an immediate
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* in the valid range (0x900000 .. 0x9fffff) is
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* converted into the correct EABI-style syscall
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* number; invalid immediates end up as values
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* > 0xfffff and are handled below as out-of-range.
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*/
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n ^= ARM_SYSCALL_BASE;
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env->eabi = 0;
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}
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}
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if (n > ARM_NR_BASE) {
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switch (n) {
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case ARM_NR_cacheflush:
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/* nop */
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break;
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case ARM_NR_set_tls:
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cpu_set_tls(env, env->regs[0]);
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env->regs[0] = 0;
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break;
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case ARM_NR_breakpoint:
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env->regs[15] -= env->thumb ? 2 : 4;
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goto excp_debug;
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case ARM_NR_get_tls:
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env->regs[0] = cpu_get_tls(env);
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break;
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default:
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if (n < 0xf0800) {
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/*
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* Syscalls 0xf0000..0xf07ff (or 0x9f0000..
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* 0x9f07ff in OABI numbering) are defined
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* to return -ENOSYS rather than raising
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* SIGILL. Note that we have already
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* removed the 0x900000 prefix.
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*/
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qemu_log_mask(LOG_UNIMP,
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"qemu: Unsupported ARM syscall: 0x%x\n",
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n);
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env->regs[0] = -TARGET_ENOSYS;
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} else {
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/*
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* Otherwise SIGILL. This includes any SWI with
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* immediate not originally 0x9fxxxx, because
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* of the earlier XOR.
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* Like the real kernel, we report the addr of the
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* SWI in the siginfo si_addr but leave the PC
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* pointing at the insn after the SWI.
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*/
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abi_ulong faultaddr = env->regs[15];
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faultaddr -= env->thumb ? 2 : 4;
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force_sig_fault(TARGET_SIGILL, TARGET_ILL_ILLTRP,
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faultaddr);
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}
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break;
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}
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} else {
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ret = do_syscall(env,
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n,
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env->regs[0],
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env->regs[1],
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env->regs[2],
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env->regs[3],
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env->regs[4],
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env->regs[5],
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0, 0);
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if (ret == -QEMU_ERESTARTSYS) {
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env->regs[15] -= env->thumb ? 2 : 4;
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} else if (ret != -QEMU_ESIGRETURN) {
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env->regs[0] = ret;
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}
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}
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}
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break;
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case EXCP_SEMIHOST:
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do_common_semihosting(cs);
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env->regs[15] += env->thumb ? 2 : 4;
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break;
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case EXCP_INTERRUPT:
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/* just indicate that signals should be handled asap */
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break;
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case EXCP_PREFETCH_ABORT:
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case EXCP_DATA_ABORT:
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/* For user-only we don't set TTBCR_EAE, so look at the FSR. */
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switch (env->exception.fsr & 0x1f) {
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case 0x1: /* Alignment */
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si_signo = TARGET_SIGBUS;
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si_code = TARGET_BUS_ADRALN;
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break;
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case 0x3: /* Access flag fault, level 1 */
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case 0x6: /* Access flag fault, level 2 */
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case 0x9: /* Domain fault, level 1 */
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case 0xb: /* Domain fault, level 2 */
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case 0xd: /* Permission fault, level 1 */
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case 0xf: /* Permission fault, level 2 */
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si_signo = TARGET_SIGSEGV;
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si_code = TARGET_SEGV_ACCERR;
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break;
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case 0x5: /* Translation fault, level 1 */
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case 0x7: /* Translation fault, level 2 */
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si_signo = TARGET_SIGSEGV;
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si_code = TARGET_SEGV_MAPERR;
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break;
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default:
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g_assert_not_reached();
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}
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force_sig_fault(si_signo, si_code, env->exception.vaddress);
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break;
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case EXCP_DEBUG:
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case EXCP_BKPT:
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excp_debug:
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force_sig_fault(TARGET_SIGTRAP, TARGET_TRAP_BRKPT, env->regs[15]);
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break;
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case EXCP_KERNEL_TRAP:
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if (do_kernel_trap(env))
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goto error;
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break;
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case EXCP_YIELD:
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/* nothing to do here for user-mode, just resume guest code */
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break;
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case EXCP_ATOMIC:
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cpu_exec_step_atomic(cs);
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break;
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default:
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error:
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EXCP_DUMP(env, "qemu: unhandled CPU exception 0x%x - aborting\n", trapnr);
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abort();
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}
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process_pending_signals(env);
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}
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}
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void target_cpu_copy_regs(CPUArchState *env, struct target_pt_regs *regs)
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{
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CPUState *cpu = env_cpu(env);
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TaskState *ts = cpu->opaque;
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struct image_info *info = ts->info;
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int i;
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cpsr_write(env, regs->uregs[16], CPSR_USER | CPSR_EXEC,
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CPSRWriteByInstr);
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for(i = 0; i < 16; i++) {
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env->regs[i] = regs->uregs[i];
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}
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#if TARGET_BIG_ENDIAN
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/* Enable BE8. */
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if (EF_ARM_EABI_VERSION(info->elf_flags) >= EF_ARM_EABI_VER4
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&& (info->elf_flags & EF_ARM_BE8)) {
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env->uncached_cpsr |= CPSR_E;
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env->cp15.sctlr_el[1] |= SCTLR_E0E;
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} else {
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env->cp15.sctlr_el[1] |= SCTLR_B;
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}
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arm_rebuild_hflags(env);
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#endif
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|
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ts->stack_base = info->start_stack;
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ts->heap_base = info->brk;
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/* This will be filled in on the first SYS_HEAPINFO call. */
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ts->heap_limit = 0;
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}
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