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xemu/accel/tcg/user-exec.c
Richard Henderson e6cd4bb59b tcg: Split CONFIG_ATOMIC128 
GCC7+ will no longer advertise support for 16-byte __atomic operations
if only cmpxchg is supported, as for x86_64.  Fortunately, x86_64 still
has support for __sync_compare_and_swap_16 and we can make use of that.
AArch64 does not have, nor ever has had such support, so open-code it.

Reviewed-by: Emilio G. Cota <cota@braap.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-10-18 19:46:36 -07:00

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/*
* User emulator execution
*
* Copyright (c) 2003-2005 Fabrice Bellard
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, see <http://www.gnu.org/licenses/>.
*/
#include "qemu/osdep.h"
#include "cpu.h"
#include "disas/disas.h"
#include "exec/exec-all.h"
#include "tcg.h"
#include "qemu/bitops.h"
#include "exec/cpu_ldst.h"
#include "translate-all.h"
#include "exec/helper-proto.h"
#include "qemu/atomic128.h"
#undef EAX
#undef ECX
#undef EDX
#undef EBX
#undef ESP
#undef EBP
#undef ESI
#undef EDI
#undef EIP
#ifdef __linux__
#include <sys/ucontext.h>
#endif
__thread uintptr_t helper_retaddr;
//#define DEBUG_SIGNAL
/* exit the current TB from a signal handler. The host registers are
restored in a state compatible with the CPU emulator
*/
static void cpu_exit_tb_from_sighandler(CPUState *cpu, sigset_t *old_set)
{
/* XXX: use siglongjmp ? */
sigprocmask(SIG_SETMASK, old_set, NULL);
cpu_loop_exit_noexc(cpu);
}
/* 'pc' is the host PC at which the exception was raised. 'address' is
the effective address of the memory exception. 'is_write' is 1 if a
write caused the exception and otherwise 0'. 'old_set' is the
signal set which should be restored */
static inline int handle_cpu_signal(uintptr_t pc, siginfo_t *info,
int is_write, sigset_t *old_set)
{
CPUState *cpu = current_cpu;
CPUClass *cc;
int ret;
unsigned long address = (unsigned long)info->si_addr;
/* We must handle PC addresses from two different sources:
* a call return address and a signal frame address.
*
* Within cpu_restore_state_from_tb we assume the former and adjust
* the address by -GETPC_ADJ so that the address is within the call
* insn so that addr does not accidentally match the beginning of the
* next guest insn.
*
* However, when the PC comes from the signal frame, it points to
* the actual faulting host insn and not a call insn. Subtracting
* GETPC_ADJ in that case may accidentally match the previous guest insn.
*
* So for the later case, adjust forward to compensate for what
* will be done later by cpu_restore_state_from_tb.
*/
if (helper_retaddr) {
pc = helper_retaddr;
} else {
pc += GETPC_ADJ;
}
/* For synchronous signals we expect to be coming from the vCPU
* thread (so current_cpu should be valid) and either from running
* code or during translation which can fault as we cross pages.
*
* If neither is true then something has gone wrong and we should
* abort rather than try and restart the vCPU execution.
*/
if (!cpu || !cpu->running) {
printf("qemu:%s received signal outside vCPU context @ pc=0x%"
PRIxPTR "\n", __func__, pc);
abort();
}
#if defined(DEBUG_SIGNAL)
printf("qemu: SIGSEGV pc=0x%08lx address=%08lx w=%d oldset=0x%08lx\n",
pc, address, is_write, *(unsigned long *)old_set);
#endif
/* XXX: locking issue */
/* Note that it is important that we don't call page_unprotect() unless
* this is really a "write to nonwriteable page" fault, because
* page_unprotect() assumes that if it is called for an access to
* a page that's writeable this means we had two threads racing and
* another thread got there first and already made the page writeable;
* so we will retry the access. If we were to call page_unprotect()
* for some other kind of fault that should really be passed to the
* guest, we'd end up in an infinite loop of retrying the faulting
* access.
*/
if (is_write && info->si_signo == SIGSEGV && info->si_code == SEGV_ACCERR &&
h2g_valid(address)) {
switch (page_unprotect(h2g(address), pc)) {
case 0:
/* Fault not caused by a page marked unwritable to protect
* cached translations, must be the guest binary's problem.
*/
break;
case 1:
/* Fault caused by protection of cached translation; TBs
* invalidated, so resume execution. Retain helper_retaddr
* for a possible second fault.
*/
return 1;
case 2:
/* Fault caused by protection of cached translation, and the
* currently executing TB was modified and must be exited
* immediately. Clear helper_retaddr for next execution.
*/
helper_retaddr = 0;
cpu_exit_tb_from_sighandler(cpu, old_set);
/* NORETURN */
default:
g_assert_not_reached();
}
}
/* Convert forcefully to guest address space, invalid addresses
are still valid segv ones */
address = h2g_nocheck(address);
cc = CPU_GET_CLASS(cpu);
/* see if it is an MMU fault */
g_assert(cc->handle_mmu_fault);
ret = cc->handle_mmu_fault(cpu, address, 0, is_write, MMU_USER_IDX);
if (ret == 0) {
/* The MMU fault was handled without causing real CPU fault.
* Retain helper_retaddr for a possible second fault.
*/
return 1;
}
/* All other paths lead to cpu_exit; clear helper_retaddr
* for next execution.
*/
helper_retaddr = 0;
if (ret < 0) {
return 0; /* not an MMU fault */
}
/* Now we have a real cpu fault. */
cpu_restore_state(cpu, pc, true);
sigprocmask(SIG_SETMASK, old_set, NULL);
cpu_loop_exit(cpu);
/* never comes here */
return 1;
}
#if defined(__i386__)
#if defined(__NetBSD__)
#include <ucontext.h>
#define EIP_sig(context) ((context)->uc_mcontext.__gregs[_REG_EIP])
#define TRAP_sig(context) ((context)->uc_mcontext.__gregs[_REG_TRAPNO])
#define ERROR_sig(context) ((context)->uc_mcontext.__gregs[_REG_ERR])
#define MASK_sig(context) ((context)->uc_sigmask)
#elif defined(__FreeBSD__) || defined(__DragonFly__)
#include <ucontext.h>
#define EIP_sig(context) (*((unsigned long *)&(context)->uc_mcontext.mc_eip))
#define TRAP_sig(context) ((context)->uc_mcontext.mc_trapno)
#define ERROR_sig(context) ((context)->uc_mcontext.mc_err)
#define MASK_sig(context) ((context)->uc_sigmask)
#elif defined(__OpenBSD__)
#define EIP_sig(context) ((context)->sc_eip)
#define TRAP_sig(context) ((context)->sc_trapno)
#define ERROR_sig(context) ((context)->sc_err)
#define MASK_sig(context) ((context)->sc_mask)
#else
#define EIP_sig(context) ((context)->uc_mcontext.gregs[REG_EIP])
#define TRAP_sig(context) ((context)->uc_mcontext.gregs[REG_TRAPNO])
#define ERROR_sig(context) ((context)->uc_mcontext.gregs[REG_ERR])
#define MASK_sig(context) ((context)->uc_sigmask)
#endif
int cpu_signal_handler(int host_signum, void *pinfo,
void *puc)
{
siginfo_t *info = pinfo;
#if defined(__NetBSD__) || defined(__FreeBSD__) || defined(__DragonFly__)
ucontext_t *uc = puc;
#elif defined(__OpenBSD__)
struct sigcontext *uc = puc;
#else
ucontext_t *uc = puc;
#endif
unsigned long pc;
int trapno;
#ifndef REG_EIP
/* for glibc 2.1 */
#define REG_EIP EIP
#define REG_ERR ERR
#define REG_TRAPNO TRAPNO
#endif
pc = EIP_sig(uc);
trapno = TRAP_sig(uc);
return handle_cpu_signal(pc, info,
trapno == 0xe ? (ERROR_sig(uc) >> 1) & 1 : 0,
&MASK_sig(uc));
}
#elif defined(__x86_64__)
#ifdef __NetBSD__
#define PC_sig(context) _UC_MACHINE_PC(context)
#define TRAP_sig(context) ((context)->uc_mcontext.__gregs[_REG_TRAPNO])
#define ERROR_sig(context) ((context)->uc_mcontext.__gregs[_REG_ERR])
#define MASK_sig(context) ((context)->uc_sigmask)
#elif defined(__OpenBSD__)
#define PC_sig(context) ((context)->sc_rip)
#define TRAP_sig(context) ((context)->sc_trapno)
#define ERROR_sig(context) ((context)->sc_err)
#define MASK_sig(context) ((context)->sc_mask)
#elif defined(__FreeBSD__) || defined(__DragonFly__)
#include <ucontext.h>
#define PC_sig(context) (*((unsigned long *)&(context)->uc_mcontext.mc_rip))
#define TRAP_sig(context) ((context)->uc_mcontext.mc_trapno)
#define ERROR_sig(context) ((context)->uc_mcontext.mc_err)
#define MASK_sig(context) ((context)->uc_sigmask)
#else
#define PC_sig(context) ((context)->uc_mcontext.gregs[REG_RIP])
#define TRAP_sig(context) ((context)->uc_mcontext.gregs[REG_TRAPNO])
#define ERROR_sig(context) ((context)->uc_mcontext.gregs[REG_ERR])
#define MASK_sig(context) ((context)->uc_sigmask)
#endif
int cpu_signal_handler(int host_signum, void *pinfo,
void *puc)
{
siginfo_t *info = pinfo;
unsigned long pc;
#if defined(__NetBSD__) || defined(__FreeBSD__) || defined(__DragonFly__)
ucontext_t *uc = puc;
#elif defined(__OpenBSD__)
struct sigcontext *uc = puc;
#else
ucontext_t *uc = puc;
#endif
pc = PC_sig(uc);
return handle_cpu_signal(pc, info,
TRAP_sig(uc) == 0xe ? (ERROR_sig(uc) >> 1) & 1 : 0,
&MASK_sig(uc));
}
#elif defined(_ARCH_PPC)
/***********************************************************************
* signal context platform-specific definitions
* From Wine
*/
#ifdef linux
/* All Registers access - only for local access */
#define REG_sig(reg_name, context) \
((context)->uc_mcontext.regs->reg_name)
/* Gpr Registers access */
#define GPR_sig(reg_num, context) REG_sig(gpr[reg_num], context)
/* Program counter */
#define IAR_sig(context) REG_sig(nip, context)
/* Machine State Register (Supervisor) */
#define MSR_sig(context) REG_sig(msr, context)
/* Count register */
#define CTR_sig(context) REG_sig(ctr, context)
/* User's integer exception register */
#define XER_sig(context) REG_sig(xer, context)
/* Link register */
#define LR_sig(context) REG_sig(link, context)
/* Condition register */
#define CR_sig(context) REG_sig(ccr, context)
/* Float Registers access */
#define FLOAT_sig(reg_num, context) \
(((double *)((char *)((context)->uc_mcontext.regs + 48 * 4)))[reg_num])
#define FPSCR_sig(context) \
(*(int *)((char *)((context)->uc_mcontext.regs + (48 + 32 * 2) * 4)))
/* Exception Registers access */
#define DAR_sig(context) REG_sig(dar, context)
#define DSISR_sig(context) REG_sig(dsisr, context)
#define TRAP_sig(context) REG_sig(trap, context)
#endif /* linux */
#if defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
#include <ucontext.h>
#define IAR_sig(context) ((context)->uc_mcontext.mc_srr0)
#define MSR_sig(context) ((context)->uc_mcontext.mc_srr1)
#define CTR_sig(context) ((context)->uc_mcontext.mc_ctr)
#define XER_sig(context) ((context)->uc_mcontext.mc_xer)
#define LR_sig(context) ((context)->uc_mcontext.mc_lr)
#define CR_sig(context) ((context)->uc_mcontext.mc_cr)
/* Exception Registers access */
#define DAR_sig(context) ((context)->uc_mcontext.mc_dar)
#define DSISR_sig(context) ((context)->uc_mcontext.mc_dsisr)
#define TRAP_sig(context) ((context)->uc_mcontext.mc_exc)
#endif /* __FreeBSD__|| __FreeBSD_kernel__ */
int cpu_signal_handler(int host_signum, void *pinfo,
void *puc)
{
siginfo_t *info = pinfo;
#if defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
ucontext_t *uc = puc;
#else
ucontext_t *uc = puc;
#endif
unsigned long pc;
int is_write;
pc = IAR_sig(uc);
is_write = 0;
#if 0
/* ppc 4xx case */
if (DSISR_sig(uc) & 0x00800000) {
is_write = 1;
}
#else
if (TRAP_sig(uc) != 0x400 && (DSISR_sig(uc) & 0x02000000)) {
is_write = 1;
}
#endif
return handle_cpu_signal(pc, info, is_write, &uc->uc_sigmask);
}
#elif defined(__alpha__)
int cpu_signal_handler(int host_signum, void *pinfo,
void *puc)
{
siginfo_t *info = pinfo;
ucontext_t *uc = puc;
uint32_t *pc = uc->uc_mcontext.sc_pc;
uint32_t insn = *pc;
int is_write = 0;
/* XXX: need kernel patch to get write flag faster */
switch (insn >> 26) {
case 0x0d: /* stw */
case 0x0e: /* stb */
case 0x0f: /* stq_u */
case 0x24: /* stf */
case 0x25: /* stg */
case 0x26: /* sts */
case 0x27: /* stt */
case 0x2c: /* stl */
case 0x2d: /* stq */
case 0x2e: /* stl_c */
case 0x2f: /* stq_c */
is_write = 1;
}
return handle_cpu_signal(pc, info, is_write, &uc->uc_sigmask);
}
#elif defined(__sparc__)
int cpu_signal_handler(int host_signum, void *pinfo,
void *puc)
{
siginfo_t *info = pinfo;
int is_write;
uint32_t insn;
#if !defined(__arch64__) || defined(CONFIG_SOLARIS)
uint32_t *regs = (uint32_t *)(info + 1);
void *sigmask = (regs + 20);
/* XXX: is there a standard glibc define ? */
unsigned long pc = regs[1];
#else
#ifdef __linux__
struct sigcontext *sc = puc;
unsigned long pc = sc->sigc_regs.tpc;
void *sigmask = (void *)sc->sigc_mask;
#elif defined(__OpenBSD__)
struct sigcontext *uc = puc;
unsigned long pc = uc->sc_pc;
void *sigmask = (void *)(long)uc->sc_mask;
#elif defined(__NetBSD__)
ucontext_t *uc = puc;
unsigned long pc = _UC_MACHINE_PC(uc);
void *sigmask = (void *)&uc->uc_sigmask;
#endif
#endif
/* XXX: need kernel patch to get write flag faster */
is_write = 0;
insn = *(uint32_t *)pc;
if ((insn >> 30) == 3) {
switch ((insn >> 19) & 0x3f) {
case 0x05: /* stb */
case 0x15: /* stba */
case 0x06: /* sth */
case 0x16: /* stha */
case 0x04: /* st */
case 0x14: /* sta */
case 0x07: /* std */
case 0x17: /* stda */
case 0x0e: /* stx */
case 0x1e: /* stxa */
case 0x24: /* stf */
case 0x34: /* stfa */
case 0x27: /* stdf */
case 0x37: /* stdfa */
case 0x26: /* stqf */
case 0x36: /* stqfa */
case 0x25: /* stfsr */
case 0x3c: /* casa */
case 0x3e: /* casxa */
is_write = 1;
break;
}
}
return handle_cpu_signal(pc, info, is_write, sigmask);
}
#elif defined(__arm__)
#if defined(__NetBSD__)
#include <ucontext.h>
#endif
int cpu_signal_handler(int host_signum, void *pinfo,
void *puc)
{
siginfo_t *info = pinfo;
#if defined(__NetBSD__)
ucontext_t *uc = puc;
#else
ucontext_t *uc = puc;
#endif
unsigned long pc;
int is_write;
#if defined(__NetBSD__)
pc = uc->uc_mcontext.__gregs[_REG_R15];
#elif defined(__GLIBC__) && (__GLIBC__ < 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ <= 3))
pc = uc->uc_mcontext.gregs[R15];
#else
pc = uc->uc_mcontext.arm_pc;
#endif
/* error_code is the FSR value, in which bit 11 is WnR (assuming a v6 or
* later processor; on v5 we will always report this as a read).
*/
is_write = extract32(uc->uc_mcontext.error_code, 11, 1);
return handle_cpu_signal(pc, info, is_write, &uc->uc_sigmask);
}
#elif defined(__aarch64__)
int cpu_signal_handler(int host_signum, void *pinfo, void *puc)
{
siginfo_t *info = pinfo;
ucontext_t *uc = puc;
uintptr_t pc = uc->uc_mcontext.pc;
uint32_t insn = *(uint32_t *)pc;
bool is_write;
/* XXX: need kernel patch to get write flag faster. */
is_write = ( (insn & 0xbfff0000) == 0x0c000000 /* C3.3.1 */
|| (insn & 0xbfe00000) == 0x0c800000 /* C3.3.2 */
|| (insn & 0xbfdf0000) == 0x0d000000 /* C3.3.3 */
|| (insn & 0xbfc00000) == 0x0d800000 /* C3.3.4 */
|| (insn & 0x3f400000) == 0x08000000 /* C3.3.6 */
|| (insn & 0x3bc00000) == 0x39000000 /* C3.3.13 */
|| (insn & 0x3fc00000) == 0x3d800000 /* ... 128bit */
/* Ingore bits 10, 11 & 21, controlling indexing. */
|| (insn & 0x3bc00000) == 0x38000000 /* C3.3.8-12 */
|| (insn & 0x3fe00000) == 0x3c800000 /* ... 128bit */
/* Ignore bits 23 & 24, controlling indexing. */
|| (insn & 0x3a400000) == 0x28000000); /* C3.3.7,14-16 */
return handle_cpu_signal(pc, info, is_write, &uc->uc_sigmask);
}
#elif defined(__s390__)
int cpu_signal_handler(int host_signum, void *pinfo,
void *puc)
{
siginfo_t *info = pinfo;
ucontext_t *uc = puc;
unsigned long pc;
uint16_t *pinsn;
int is_write = 0;
pc = uc->uc_mcontext.psw.addr;
/* ??? On linux, the non-rt signal handler has 4 (!) arguments instead
of the normal 2 arguments. The 3rd argument contains the "int_code"
from the hardware which does in fact contain the is_write value.
The rt signal handler, as far as I can tell, does not give this value
at all. Not that we could get to it from here even if it were. */
/* ??? This is not even close to complete, since it ignores all
of the read-modify-write instructions. */
pinsn = (uint16_t *)pc;
switch (pinsn[0] >> 8) {
case 0x50: /* ST */
case 0x42: /* STC */
case 0x40: /* STH */
is_write = 1;
break;
case 0xc4: /* RIL format insns */
switch (pinsn[0] & 0xf) {
case 0xf: /* STRL */
case 0xb: /* STGRL */
case 0x7: /* STHRL */
is_write = 1;
}
break;
case 0xe3: /* RXY format insns */
switch (pinsn[2] & 0xff) {
case 0x50: /* STY */
case 0x24: /* STG */
case 0x72: /* STCY */
case 0x70: /* STHY */
case 0x8e: /* STPQ */
case 0x3f: /* STRVH */
case 0x3e: /* STRV */
case 0x2f: /* STRVG */
is_write = 1;
}
break;
}
return handle_cpu_signal(pc, info, is_write, &uc->uc_sigmask);
}
#elif defined(__mips__)
int cpu_signal_handler(int host_signum, void *pinfo,
void *puc)
{
siginfo_t *info = pinfo;
ucontext_t *uc = puc;
greg_t pc = uc->uc_mcontext.pc;
int is_write;
/* XXX: compute is_write */
is_write = 0;
return handle_cpu_signal(pc, info, is_write, &uc->uc_sigmask);
}
#else
#error host CPU specific signal handler needed
#endif
/* The softmmu versions of these helpers are in cputlb.c. */
/* Do not allow unaligned operations to proceed. Return the host address. */
static void *atomic_mmu_lookup(CPUArchState *env, target_ulong addr,
int size, uintptr_t retaddr)
{
/* Enforce qemu required alignment. */
if (unlikely(addr & (size - 1))) {
cpu_loop_exit_atomic(ENV_GET_CPU(env), retaddr);
}
helper_retaddr = retaddr;
return g2h(addr);
}
/* Macro to call the above, with local variables from the use context. */
#define ATOMIC_MMU_DECLS do {} while (0)
#define ATOMIC_MMU_LOOKUP atomic_mmu_lookup(env, addr, DATA_SIZE, GETPC())
#define ATOMIC_MMU_CLEANUP do { helper_retaddr = 0; } while (0)
#define ATOMIC_NAME(X) HELPER(glue(glue(atomic_ ## X, SUFFIX), END))
#define EXTRA_ARGS
#define DATA_SIZE 1
#include "atomic_template.h"
#define DATA_SIZE 2
#include "atomic_template.h"
#define DATA_SIZE 4
#include "atomic_template.h"
#ifdef CONFIG_ATOMIC64
#define DATA_SIZE 8
#include "atomic_template.h"
#endif
/* The following is only callable from other helpers, and matches up
with the softmmu version. */
#if HAVE_ATOMIC128 || HAVE_CMPXCHG128
#undef EXTRA_ARGS
#undef ATOMIC_NAME
#undef ATOMIC_MMU_LOOKUP
#define EXTRA_ARGS , TCGMemOpIdx oi, uintptr_t retaddr
#define ATOMIC_NAME(X) \
HELPER(glue(glue(glue(atomic_ ## X, SUFFIX), END), _mmu))
#define ATOMIC_MMU_LOOKUP atomic_mmu_lookup(env, addr, DATA_SIZE, retaddr)
#define DATA_SIZE 16
#include "atomic_template.h"
#endif
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