qemu/linux-user/m68k/signal.c
Peter Maydell e285977e77 linux-user: Remove dead error-checking code
Remove some dead code spotted by Coverity (CID 1009855,
1390854, 1390847). The underlying cause in all these cases
is the same: QEMU's put_user operations can't result in
errors, but the kernel's equivalent does. So when code
was copied from the kernel signal-frame-setup/teardown
code, checks on error flags that were needed in the kernel
became dead code for us.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Message-Id: <20181019161715.12122-1-peter.maydell@linaro.org>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
2018-11-12 15:43:07 +01:00

416 lines
11 KiB
C

/*
* Emulation of Linux signals
*
* Copyright (c) 2003 Fabrice Bellard
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <http://www.gnu.org/licenses/>.
*/
#include "qemu/osdep.h"
#include "qemu.h"
#include "signal-common.h"
#include "linux-user/trace.h"
struct target_sigcontext {
abi_ulong sc_mask;
abi_ulong sc_usp;
abi_ulong sc_d0;
abi_ulong sc_d1;
abi_ulong sc_a0;
abi_ulong sc_a1;
unsigned short sc_sr;
abi_ulong sc_pc;
};
struct target_sigframe
{
abi_ulong pretcode;
int sig;
int code;
abi_ulong psc;
char retcode[8];
abi_ulong extramask[TARGET_NSIG_WORDS-1];
struct target_sigcontext sc;
};
typedef int target_greg_t;
#define TARGET_NGREG 18
typedef target_greg_t target_gregset_t[TARGET_NGREG];
typedef struct target_fpregset {
int f_fpcntl[3];
int f_fpregs[8*3];
} target_fpregset_t;
struct target_mcontext {
int version;
target_gregset_t gregs;
target_fpregset_t fpregs;
};
#define TARGET_MCONTEXT_VERSION 2
struct target_ucontext {
abi_ulong tuc_flags;
abi_ulong tuc_link;
target_stack_t tuc_stack;
struct target_mcontext tuc_mcontext;
abi_long tuc_filler[80];
target_sigset_t tuc_sigmask;
};
struct target_rt_sigframe
{
abi_ulong pretcode;
int sig;
abi_ulong pinfo;
abi_ulong puc;
char retcode[8];
struct target_siginfo info;
struct target_ucontext uc;
};
static void setup_sigcontext(struct target_sigcontext *sc, CPUM68KState *env,
abi_ulong mask)
{
uint32_t sr = (env->sr & 0xff00) | cpu_m68k_get_ccr(env);
__put_user(mask, &sc->sc_mask);
__put_user(env->aregs[7], &sc->sc_usp);
__put_user(env->dregs[0], &sc->sc_d0);
__put_user(env->dregs[1], &sc->sc_d1);
__put_user(env->aregs[0], &sc->sc_a0);
__put_user(env->aregs[1], &sc->sc_a1);
__put_user(sr, &sc->sc_sr);
__put_user(env->pc, &sc->sc_pc);
}
static void
restore_sigcontext(CPUM68KState *env, struct target_sigcontext *sc)
{
int temp;
__get_user(env->aregs[7], &sc->sc_usp);
__get_user(env->dregs[0], &sc->sc_d0);
__get_user(env->dregs[1], &sc->sc_d1);
__get_user(env->aregs[0], &sc->sc_a0);
__get_user(env->aregs[1], &sc->sc_a1);
__get_user(env->pc, &sc->sc_pc);
__get_user(temp, &sc->sc_sr);
cpu_m68k_set_ccr(env, temp);
}
/*
* Determine which stack to use..
*/
static inline abi_ulong
get_sigframe(struct target_sigaction *ka, CPUM68KState *regs,
size_t frame_size)
{
abi_ulong sp;
sp = target_sigsp(get_sp_from_cpustate(regs), ka);
return ((sp - frame_size) & -8UL);
}
void setup_frame(int sig, struct target_sigaction *ka,
target_sigset_t *set, CPUM68KState *env)
{
struct target_sigframe *frame;
abi_ulong frame_addr;
abi_ulong retcode_addr;
abi_ulong sc_addr;
int i;
frame_addr = get_sigframe(ka, env, sizeof *frame);
trace_user_setup_frame(env, frame_addr);
if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0)) {
goto give_sigsegv;
}
__put_user(sig, &frame->sig);
sc_addr = frame_addr + offsetof(struct target_sigframe, sc);
__put_user(sc_addr, &frame->psc);
setup_sigcontext(&frame->sc, env, set->sig[0]);
for(i = 1; i < TARGET_NSIG_WORDS; i++) {
__put_user(set->sig[i], &frame->extramask[i - 1]);
}
/* Set up to return from userspace. */
retcode_addr = frame_addr + offsetof(struct target_sigframe, retcode);
__put_user(retcode_addr, &frame->pretcode);
/* moveq #,d0; trap #0 */
__put_user(0x70004e40 + (TARGET_NR_sigreturn << 16),
(uint32_t *)(frame->retcode));
/* Set up to return from userspace */
env->aregs[7] = frame_addr;
env->pc = ka->_sa_handler;
unlock_user_struct(frame, frame_addr, 1);
return;
give_sigsegv:
force_sigsegv(sig);
}
static inline void target_rt_save_fpu_state(struct target_ucontext *uc,
CPUM68KState *env)
{
int i;
target_fpregset_t *fpregs = &uc->tuc_mcontext.fpregs;
__put_user(env->fpcr, &fpregs->f_fpcntl[0]);
__put_user(env->fpsr, &fpregs->f_fpcntl[1]);
/* fpiar is not emulated */
for (i = 0; i < 8; i++) {
uint32_t high = env->fregs[i].d.high << 16;
__put_user(high, &fpregs->f_fpregs[i * 3]);
__put_user(env->fregs[i].d.low,
(uint64_t *)&fpregs->f_fpregs[i * 3 + 1]);
}
}
static inline int target_rt_setup_ucontext(struct target_ucontext *uc,
CPUM68KState *env)
{
target_greg_t *gregs = uc->tuc_mcontext.gregs;
uint32_t sr = (env->sr & 0xff00) | cpu_m68k_get_ccr(env);
__put_user(TARGET_MCONTEXT_VERSION, &uc->tuc_mcontext.version);
__put_user(env->dregs[0], &gregs[0]);
__put_user(env->dregs[1], &gregs[1]);
__put_user(env->dregs[2], &gregs[2]);
__put_user(env->dregs[3], &gregs[3]);
__put_user(env->dregs[4], &gregs[4]);
__put_user(env->dregs[5], &gregs[5]);
__put_user(env->dregs[6], &gregs[6]);
__put_user(env->dregs[7], &gregs[7]);
__put_user(env->aregs[0], &gregs[8]);
__put_user(env->aregs[1], &gregs[9]);
__put_user(env->aregs[2], &gregs[10]);
__put_user(env->aregs[3], &gregs[11]);
__put_user(env->aregs[4], &gregs[12]);
__put_user(env->aregs[5], &gregs[13]);
__put_user(env->aregs[6], &gregs[14]);
__put_user(env->aregs[7], &gregs[15]);
__put_user(env->pc, &gregs[16]);
__put_user(sr, &gregs[17]);
target_rt_save_fpu_state(uc, env);
return 0;
}
static inline void target_rt_restore_fpu_state(CPUM68KState *env,
struct target_ucontext *uc)
{
int i;
target_fpregset_t *fpregs = &uc->tuc_mcontext.fpregs;
uint32_t fpcr;
__get_user(fpcr, &fpregs->f_fpcntl[0]);
cpu_m68k_set_fpcr(env, fpcr);
__get_user(env->fpsr, &fpregs->f_fpcntl[1]);
/* fpiar is not emulated */
for (i = 0; i < 8; i++) {
uint32_t high;
__get_user(high, &fpregs->f_fpregs[i * 3]);
env->fregs[i].d.high = high >> 16;
__get_user(env->fregs[i].d.low,
(uint64_t *)&fpregs->f_fpregs[i * 3 + 1]);
}
}
static inline int target_rt_restore_ucontext(CPUM68KState *env,
struct target_ucontext *uc)
{
int temp;
target_greg_t *gregs = uc->tuc_mcontext.gregs;
__get_user(temp, &uc->tuc_mcontext.version);
if (temp != TARGET_MCONTEXT_VERSION)
goto badframe;
/* restore passed registers */
__get_user(env->dregs[0], &gregs[0]);
__get_user(env->dregs[1], &gregs[1]);
__get_user(env->dregs[2], &gregs[2]);
__get_user(env->dregs[3], &gregs[3]);
__get_user(env->dregs[4], &gregs[4]);
__get_user(env->dregs[5], &gregs[5]);
__get_user(env->dregs[6], &gregs[6]);
__get_user(env->dregs[7], &gregs[7]);
__get_user(env->aregs[0], &gregs[8]);
__get_user(env->aregs[1], &gregs[9]);
__get_user(env->aregs[2], &gregs[10]);
__get_user(env->aregs[3], &gregs[11]);
__get_user(env->aregs[4], &gregs[12]);
__get_user(env->aregs[5], &gregs[13]);
__get_user(env->aregs[6], &gregs[14]);
__get_user(env->aregs[7], &gregs[15]);
__get_user(env->pc, &gregs[16]);
__get_user(temp, &gregs[17]);
cpu_m68k_set_ccr(env, temp);
target_rt_restore_fpu_state(env, uc);
return 0;
badframe:
return 1;
}
void setup_rt_frame(int sig, struct target_sigaction *ka,
target_siginfo_t *info,
target_sigset_t *set, CPUM68KState *env)
{
struct target_rt_sigframe *frame;
abi_ulong frame_addr;
abi_ulong retcode_addr;
abi_ulong info_addr;
abi_ulong uc_addr;
int err = 0;
int i;
frame_addr = get_sigframe(ka, env, sizeof *frame);
trace_user_setup_rt_frame(env, frame_addr);
if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0)) {
goto give_sigsegv;
}
__put_user(sig, &frame->sig);
info_addr = frame_addr + offsetof(struct target_rt_sigframe, info);
__put_user(info_addr, &frame->pinfo);
uc_addr = frame_addr + offsetof(struct target_rt_sigframe, uc);
__put_user(uc_addr, &frame->puc);
tswap_siginfo(&frame->info, info);
/* Create the ucontext */
__put_user(0, &frame->uc.tuc_flags);
__put_user(0, &frame->uc.tuc_link);
target_save_altstack(&frame->uc.tuc_stack, env);
err |= target_rt_setup_ucontext(&frame->uc, env);
if (err)
goto give_sigsegv;
for(i = 0; i < TARGET_NSIG_WORDS; i++) {
__put_user(set->sig[i], &frame->uc.tuc_sigmask.sig[i]);
}
/* Set up to return from userspace. */
retcode_addr = frame_addr + offsetof(struct target_sigframe, retcode);
__put_user(retcode_addr, &frame->pretcode);
/* moveq #,d0; notb d0; trap #0 */
__put_user(0x70004600 + ((TARGET_NR_rt_sigreturn ^ 0xff) << 16),
(uint32_t *)(frame->retcode + 0));
__put_user(0x4e40, (uint16_t *)(frame->retcode + 4));
/* Set up to return from userspace */
env->aregs[7] = frame_addr;
env->pc = ka->_sa_handler;
unlock_user_struct(frame, frame_addr, 1);
return;
give_sigsegv:
unlock_user_struct(frame, frame_addr, 1);
force_sigsegv(sig);
}
long do_sigreturn(CPUM68KState *env)
{
struct target_sigframe *frame;
abi_ulong frame_addr = env->aregs[7] - 4;
target_sigset_t target_set;
sigset_t set;
int i;
trace_user_do_sigreturn(env, frame_addr);
if (!lock_user_struct(VERIFY_READ, frame, frame_addr, 1))
goto badframe;
/* set blocked signals */
__get_user(target_set.sig[0], &frame->sc.sc_mask);
for(i = 1; i < TARGET_NSIG_WORDS; i++) {
__get_user(target_set.sig[i], &frame->extramask[i - 1]);
}
target_to_host_sigset_internal(&set, &target_set);
set_sigmask(&set);
/* restore registers */
restore_sigcontext(env, &frame->sc);
unlock_user_struct(frame, frame_addr, 0);
return -TARGET_QEMU_ESIGRETURN;
badframe:
force_sig(TARGET_SIGSEGV);
return -TARGET_QEMU_ESIGRETURN;
}
long do_rt_sigreturn(CPUM68KState *env)
{
struct target_rt_sigframe *frame;
abi_ulong frame_addr = env->aregs[7] - 4;
sigset_t set;
trace_user_do_rt_sigreturn(env, frame_addr);
if (!lock_user_struct(VERIFY_READ, frame, frame_addr, 1))
goto badframe;
target_to_host_sigset(&set, &frame->uc.tuc_sigmask);
set_sigmask(&set);
/* restore registers */
if (target_rt_restore_ucontext(env, &frame->uc))
goto badframe;
if (do_sigaltstack(frame_addr +
offsetof(struct target_rt_sigframe, uc.tuc_stack),
0, get_sp_from_cpustate(env)) == -EFAULT)
goto badframe;
unlock_user_struct(frame, frame_addr, 0);
return -TARGET_QEMU_ESIGRETURN;
badframe:
unlock_user_struct(frame, frame_addr, 0);
force_sig(TARGET_SIGSEGV);
return -TARGET_QEMU_ESIGRETURN;
}