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RISC-V Linux User Emulation

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Implementation of linux user emulation for RISC-V.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Sagar Karandikar <sagark@eecs.berkeley.edu>
Signed-off-by: Michael Clark <mjc@sifive.com>
This commit is contained in:
Michael Clark
2018-03-03 01:31:11 +13:00
parent 65c5b75c38
commit 47ae93cdfe
13 changed files with 1012 additions and 6 deletions
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203
linux-user/signal.c
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@@ -535,6 +535,7 @@ static void force_sig(int sig)
* up the signal frame. oldsig is the signal we were trying to handle
* at the point of failure.
*/
#if !defined(TARGET_RISCV)
static void force_sigsegv(int oldsig)
{
if (oldsig == SIGSEGV) {
@@ -547,6 +548,8 @@ static void force_sigsegv(int oldsig)
}
#endif
#endif
/* abort execution with signal */
static void QEMU_NORETURN dump_core_and_abort(int target_sig)
{
@@ -6385,6 +6388,203 @@ long do_rt_sigreturn(CPUTLGState *env)
return -TARGET_QEMU_ESIGRETURN;
}
#elif defined(TARGET_RISCV)
/* Signal handler invocation must be transparent for the code being
interrupted. Complete CPU (hart) state is saved on entry and restored
before returning from the handler. Process sigmask is also saved to block
signals while the handler is running. The handler gets its own stack,
which also doubles as storage for the CPU state and sigmask.
The code below is qemu re-implementation of arch/riscv/kernel/signal.c */
struct target_sigcontext {
abi_long pc;
abi_long gpr[31]; /* x0 is not present, so all offsets must be -1 */
uint64_t fpr[32];
uint32_t fcsr;
}; /* cf. riscv-linux:arch/riscv/include/uapi/asm/ptrace.h */
struct target_ucontext {
unsigned long uc_flags;
struct target_ucontext *uc_link;
target_stack_t uc_stack;
struct target_sigcontext uc_mcontext;
target_sigset_t uc_sigmask;
};
struct target_rt_sigframe {
uint32_t tramp[2]; /* not in kernel, which uses VDSO instead */
struct target_siginfo info;
struct target_ucontext uc;
};
static abi_ulong get_sigframe(struct target_sigaction *ka,
CPURISCVState *regs, size_t framesize)
{
abi_ulong sp = regs->gpr[xSP];
int onsigstack = on_sig_stack(sp);
/* redzone */
/* This is the X/Open sanctioned signal stack switching. */
if ((ka->sa_flags & TARGET_SA_ONSTACK) != 0 && !onsigstack) {
sp = target_sigaltstack_used.ss_sp + target_sigaltstack_used.ss_size;
}
sp -= framesize;
sp &= ~3UL; /* align sp on 4-byte boundary */
/* If we are on the alternate signal stack and would overflow it, don't.
Return an always-bogus address instead so we will die with SIGSEGV. */
if (onsigstack && !likely(on_sig_stack(sp))) {
return -1L;
}
return sp;
}
static void setup_sigcontext(struct target_sigcontext *sc, CPURISCVState *env)
{
int i;
__put_user(env->pc, &sc->pc);
for (i = 1; i < 32; i++) {
__put_user(env->gpr[i], &sc->gpr[i - 1]);
}
for (i = 0; i < 32; i++) {
__put_user(env->fpr[i], &sc->fpr[i]);
}
uint32_t fcsr = csr_read_helper(env, CSR_FCSR); /*riscv_get_fcsr(env);*/
__put_user(fcsr, &sc->fcsr);
}
static void setup_ucontext(struct target_ucontext *uc,
CPURISCVState *env, target_sigset_t *set)
{
abi_ulong ss_sp = (target_ulong)target_sigaltstack_used.ss_sp;
abi_ulong ss_flags = sas_ss_flags(env->gpr[xSP]);
abi_ulong ss_size = target_sigaltstack_used.ss_size;
__put_user(0, &(uc->uc_flags));
__put_user(0, &(uc->uc_link));
__put_user(ss_sp, &(uc->uc_stack.ss_sp));
__put_user(ss_flags, &(uc->uc_stack.ss_flags));
__put_user(ss_size, &(uc->uc_stack.ss_size));
int i;
for (i = 0; i < TARGET_NSIG_WORDS; i++) {
__put_user(set->sig[i], &(uc->uc_sigmask.sig[i]));
}
setup_sigcontext(&uc->uc_mcontext, env);
}
static inline void install_sigtramp(uint32_t *tramp)
{
__put_user(0x08b00893, tramp + 0); /* li a7, 139 = __NR_rt_sigreturn */
__put_user(0x00000073, tramp + 1); /* ecall */
}
static void setup_rt_frame(int sig, struct target_sigaction *ka,
target_siginfo_t *info,
target_sigset_t *set, CPURISCVState *env)
{
abi_ulong frame_addr;
struct target_rt_sigframe *frame;
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 badframe;
}
setup_ucontext(&frame->uc, env, set);
tswap_siginfo(&frame->info, info);
install_sigtramp(frame->tramp);
env->pc = ka->_sa_handler;
env->gpr[xSP] = frame_addr;
env->gpr[xA0] = sig;
env->gpr[xA1] = frame_addr + offsetof(struct target_rt_sigframe, info);
env->gpr[xA2] = frame_addr + offsetof(struct target_rt_sigframe, uc);
env->gpr[xRA] = frame_addr + offsetof(struct target_rt_sigframe, tramp);
return;
badframe:
unlock_user_struct(frame, frame_addr, 1);
if (sig == TARGET_SIGSEGV) {
ka->_sa_handler = TARGET_SIG_DFL;
}
force_sig(TARGET_SIGSEGV);
}
static void restore_sigcontext(CPURISCVState *env, struct target_sigcontext *sc)
{
int i;
__get_user(env->pc, &sc->pc);
for (i = 1; i < 32; ++i) {
__get_user(env->gpr[i], &sc->gpr[i - 1]);
}
for (i = 0; i < 32; ++i) {
__get_user(env->fpr[i], &sc->fpr[i]);
}
uint32_t fcsr;
__get_user(fcsr, &sc->fcsr);
csr_write_helper(env, fcsr, CSR_FCSR);
}
static void restore_ucontext(CPURISCVState *env, struct target_ucontext *uc)
{
sigset_t blocked;
target_sigset_t target_set;
int i;
target_sigemptyset(&target_set);
for (i = 0; i < TARGET_NSIG_WORDS; i++) {
__get_user(target_set.sig[i], &(uc->uc_sigmask.sig[i]));
}
target_to_host_sigset_internal(&blocked, &target_set);
set_sigmask(&blocked);
restore_sigcontext(env, &uc->uc_mcontext);
}
long do_rt_sigreturn(CPURISCVState *env)
{
struct target_rt_sigframe *frame;
abi_ulong frame_addr;
frame_addr = env->gpr[xSP];
trace_user_do_sigreturn(env, frame_addr);
if (!lock_user_struct(VERIFY_READ, frame, frame_addr, 1)) {
goto badframe;
}
restore_ucontext(env, &frame->uc);
if (do_sigaltstack(frame_addr + offsetof(struct target_rt_sigframe,
uc.uc_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 0;
}
#elif defined(TARGET_HPPA)
struct target_sigcontext {
@@ -6676,7 +6876,8 @@ static void handle_pending_signal(CPUArchState *cpu_env, int sig,
#if defined(TARGET_ABI_MIPSN32) || defined(TARGET_ABI_MIPSN64) \
|| defined(TARGET_OPENRISC) || defined(TARGET_TILEGX) \
|| defined(TARGET_PPC64) || defined(TARGET_HPPA) \
|| defined(TARGET_NIOS2) || defined(TARGET_X86_64)
|| defined(TARGET_NIOS2) || defined(TARGET_X86_64) \
|| defined(TARGET_RISCV)
/* These targets do not have traditional signals. */
setup_rt_frame(sig, sa, &k->info, &target_old_set, cpu_env);
#else