From e8f29049b1e904068ce874e6a40b6ad18b26e121 Mon Sep 17 00:00:00 2001 From: Richard Henderson Date: Sun, 27 May 2018 14:02:17 -0500 Subject: [PATCH] linux-user: Implement signals for openrisc All of the existing code was boilerplate from elsewhere, and would crash the guest upon the first signal. Signed-off-by: Richard Henderson Signed-off-by: Stafford Horne --- v2: Add a comment to the new definition of target_pt_regs. Install the signal mask into the ucontext. v3: Incorporate feedback from Laurent. --- linux-user/openrisc/signal.c | 213 +++++++++++---------------- linux-user/openrisc/target_syscall.h | 28 +--- linux-user/signal.c | 2 +- target/openrisc/cpu.c | 1 + 4 files changed, 92 insertions(+), 152 deletions(-) diff --git a/linux-user/openrisc/signal.c b/linux-user/openrisc/signal.c index 8be0b74001..232ad82b98 100644 --- a/linux-user/openrisc/signal.c +++ b/linux-user/openrisc/signal.c @@ -21,124 +21,69 @@ #include "signal-common.h" #include "linux-user/trace.h" -struct target_sigcontext { +typedef struct target_sigcontext { struct target_pt_regs regs; abi_ulong oldmask; - abi_ulong usp; -}; +} target_sigcontext; -struct target_ucontext { +typedef struct target_ucontext { abi_ulong tuc_flags; abi_ulong tuc_link; target_stack_t tuc_stack; - struct target_sigcontext tuc_mcontext; + target_sigcontext tuc_mcontext; target_sigset_t tuc_sigmask; /* mask last for extensibility */ -}; +} target_ucontext; -struct target_rt_sigframe { - abi_ulong pinfo; - uint64_t puc; +typedef struct target_rt_sigframe { struct target_siginfo info; - struct target_sigcontext sc; - struct target_ucontext uc; - unsigned char retcode[16]; /* trampoline code */ -}; + target_ucontext uc; + uint32_t retcode[4]; /* trampoline code */ +} target_rt_sigframe; -/* This is the asm-generic/ucontext.h version */ -#if 0 -static int restore_sigcontext(CPUOpenRISCState *regs, - struct target_sigcontext *sc) +static void restore_sigcontext(CPUOpenRISCState *env, target_sigcontext *sc) { - unsigned int err = 0; - unsigned long old_usp; + int i; + abi_ulong v; - /* Alwys make any pending restarted system call return -EINTR */ - current_thread_info()->restart_block.fn = do_no_restart_syscall; - - /* restore the regs from &sc->regs (same as sc, since regs is first) - * (sc is already checked for VERIFY_READ since the sigframe was - * checked in sys_sigreturn previously) - */ - - if (copy_from_user(regs, &sc, sizeof(struct target_pt_regs))) { - goto badframe; + for (i = 0; i < 32; ++i) { + __get_user(v, &sc->regs.gpr[i]); + cpu_set_gpr(env, i, v); } + __get_user(env->pc, &sc->regs.pc); - /* make sure the U-flag is set so user-mode cannot fool us */ - - regs->sr &= ~SR_SM; - - /* restore the old USP as it was before we stacked the sc etc. - * (we cannot just pop the sigcontext since we aligned the sp and - * stuff after pushing it) - */ - - __get_user(old_usp, &sc->usp); - phx_signal("old_usp 0x%lx", old_usp); - - __PHX__ REALLY /* ??? */ - wrusp(old_usp); - regs->gpr[1] = old_usp; - - /* TODO: the other ports use regs->orig_XX to disable syscall checks - * after this completes, but we don't use that mechanism. maybe we can - * use it now ? - */ - - return err; - -badframe: - return 1; + /* Make sure the supervisor flag is clear. */ + __get_user(v, &sc->regs.sr); + cpu_set_sr(env, v & ~SR_SM); } -#endif /* Set up a signal frame. */ -static void setup_sigcontext(struct target_sigcontext *sc, - CPUOpenRISCState *regs, - unsigned long mask) +static void setup_sigcontext(target_sigcontext *sc, CPUOpenRISCState *env) { - unsigned long usp = cpu_get_gpr(regs, 1); + int i; - /* copy the regs. they are first in sc so we can use sc directly */ + for (i = 0; i < 32; ++i) { + __put_user(cpu_get_gpr(env, i), &sc->regs.gpr[i]); + } - /*copy_to_user(&sc, regs, sizeof(struct target_pt_regs));*/ - - /* Set the frametype to CRIS_FRAME_NORMAL for the execution of - the signal handler. The frametype will be restored to its previous - value in restore_sigcontext. */ - /*regs->frametype = CRIS_FRAME_NORMAL;*/ - - /* then some other stuff */ - __put_user(mask, &sc->oldmask); - __put_user(usp, &sc->usp); -} - -static inline unsigned long align_sigframe(unsigned long sp) -{ - return sp & ~3UL; + __put_user(env->pc, &sc->regs.pc); + __put_user(cpu_get_sr(env), &sc->regs.sr); } static inline abi_ulong get_sigframe(struct target_sigaction *ka, - CPUOpenRISCState *regs, + CPUOpenRISCState *env, size_t frame_size) { - unsigned long sp = get_sp_from_cpustate(regs); - int onsigstack = on_sig_stack(sp); + target_ulong sp = get_sp_from_cpustate(env); - /* redzone */ - sp = target_sigsp(sp, ka); - - sp = align_sigframe(sp - frame_size); - - /* - * 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. + /* Honor redzone now. If we swap to signal stack, no need to waste + * the 128 bytes by subtracting afterward. */ + sp -= 128; - if (onsigstack && !likely(on_sig_stack(sp))) { - return -1L; - } + sp = target_sigsp(sp, ka); + sp -= frame_size; + sp = QEMU_ALIGN_DOWN(sp, 4); return sp; } @@ -147,11 +92,9 @@ void setup_rt_frame(int sig, struct target_sigaction *ka, target_siginfo_t *info, target_sigset_t *set, CPUOpenRISCState *env) { - int err = 0; abi_ulong frame_addr; - unsigned long return_ip; - struct target_rt_sigframe *frame; - abi_ulong info_addr, uc_addr; + target_rt_sigframe *frame; + int i; frame_addr = get_sigframe(ka, env, sizeof(*frame)); trace_user_setup_rt_frame(env, frame_addr); @@ -159,47 +102,37 @@ void setup_rt_frame(int sig, struct target_sigaction *ka, goto give_sigsegv; } - 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); - if (ka->sa_flags & SA_SIGINFO) { tswap_siginfo(&frame->info, info); } - /*err |= __clear_user(&frame->uc, offsetof(ucontext_t, uc_mcontext));*/ __put_user(0, &frame->uc.tuc_flags); __put_user(0, &frame->uc.tuc_link); + target_save_altstack(&frame->uc.tuc_stack, env); - setup_sigcontext(&frame->sc, env, set->sig[0]); - - /*err |= copy_to_user(frame->uc.tuc_sigmask, set, sizeof(*set));*/ - - /* trampoline - the desired return ip is the retcode itself */ - return_ip = (unsigned long)&frame->retcode; - /* This is l.ori r11,r0,__NR_sigreturn, l.sys 1 */ - __put_user(0xa960, (short *)(frame->retcode + 0)); - __put_user(TARGET_NR_rt_sigreturn, (short *)(frame->retcode + 2)); - __put_user(0x20000001, (unsigned long *)(frame->retcode + 4)); - __put_user(0x15000000, (unsigned long *)(frame->retcode + 8)); - - if (err) { - goto give_sigsegv; + setup_sigcontext(&frame->uc.tuc_mcontext, env); + for (i = 0; i < TARGET_NSIG_WORDS; ++i) { + __put_user(set->sig[i], &frame->uc.tuc_sigmask.sig[i]); } - /* TODO what is the current->exec_domain stuff and invmap ? */ + /* This is l.ori r11,r0,__NR_sigreturn; l.sys 1; l.nop; l.nop */ + __put_user(0xa9600000 | TARGET_NR_rt_sigreturn, frame->retcode + 0); + __put_user(0x20000001, frame->retcode + 1); + __put_user(0x15000000, frame->retcode + 2); + __put_user(0x15000000, frame->retcode + 3); /* Set up registers for signal handler */ - env->pc = (unsigned long)ka->_sa_handler; /* what we enter NOW */ - cpu_set_gpr(env, 9, (unsigned long)return_ip); /* what we enter LATER */ - cpu_set_gpr(env, 3, (unsigned long)sig); /* arg 1: signo */ - cpu_set_gpr(env, 4, (unsigned long)&frame->info); /* arg 2: (siginfo_t*) */ - cpu_set_gpr(env, 5, (unsigned long)&frame->uc); /* arg 3: ucontext */ - - /* actually move the usp to reflect the stacked frame */ - cpu_set_gpr(env, 1, (unsigned long)frame); + cpu_set_gpr(env, 9, frame_addr + offsetof(target_rt_sigframe, retcode)); + cpu_set_gpr(env, 3, sig); + cpu_set_gpr(env, 4, frame_addr + offsetof(target_rt_sigframe, info)); + cpu_set_gpr(env, 5, frame_addr + offsetof(target_rt_sigframe, uc)); + cpu_set_gpr(env, 1, frame_addr); + /* For debugging convenience, set ppc to the insn that faulted. */ + env->ppc = env->pc; + /* When setting the PC for the signal handler, exit delay slot. */ + env->pc = ka->_sa_handler; + env->dflag = 0; return; give_sigsegv: @@ -207,16 +140,34 @@ give_sigsegv: force_sigsegv(sig); } -long do_sigreturn(CPUOpenRISCState *env) -{ - trace_user_do_sigreturn(env, 0); - fprintf(stderr, "do_sigreturn: not implemented\n"); - return -TARGET_ENOSYS; -} - long do_rt_sigreturn(CPUOpenRISCState *env) { + abi_ulong frame_addr = get_sp_from_cpustate(env); + target_rt_sigframe *frame; + sigset_t set; + trace_user_do_rt_sigreturn(env, 0); - fprintf(stderr, "do_rt_sigreturn: not implemented\n"); - return -TARGET_ENOSYS; + if (!lock_user_struct(VERIFY_READ, frame, frame_addr, 1)) { + goto badframe; + } + if (frame_addr & 3) { + goto badframe; + } + + target_to_host_sigset(&set, &frame->uc.tuc_sigmask); + set_sigmask(&set); + + restore_sigcontext(env, &frame->uc.tuc_mcontext); + if (do_sigaltstack(frame_addr + offsetof(target_rt_sigframe, uc.tuc_stack), + 0, frame_addr) == -EFAULT) { + goto badframe; + } + + unlock_user_struct(frame, frame_addr, 0); + return cpu_get_gpr(env, 11); + + badframe: + unlock_user_struct(frame, frame_addr, 0); + force_sig(TARGET_SIGSEGV); + return 0; } diff --git a/linux-user/openrisc/target_syscall.h b/linux-user/openrisc/target_syscall.h index 03104f80af..d586d2a018 100644 --- a/linux-user/openrisc/target_syscall.h +++ b/linux-user/openrisc/target_syscall.h @@ -1,27 +1,15 @@ #ifndef OPENRISC_TARGET_SYSCALL_H #define OPENRISC_TARGET_SYSCALL_H +/* Note that in linux/arch/openrisc/include/uapi/asm/ptrace.h, + * this is called user_regs_struct. Given that this is what + * is used within struct sigcontext we need this definition. + * However, elfload.c wants this name. + */ struct target_pt_regs { - union { - struct { - /* Named registers */ - uint32_t sr; /* Stored in place of r0 */ - target_ulong sp; /* r1 */ - }; - struct { - /* Old style */ - target_ulong offset[2]; - target_ulong gprs[30]; - }; - struct { - /* New style */ - target_ulong gpr[32]; - }; - }; - target_ulong pc; - target_ulong orig_gpr11; /* For restarting system calls */ - uint32_t syscallno; /* Syscall number (used by strace) */ - target_ulong dummy; /* Cheap alignment fix */ + abi_ulong gpr[32]; + abi_ulong pc; + abi_ulong sr; }; #define UNAME_MACHINE "openrisc" diff --git a/linux-user/signal.c b/linux-user/signal.c index be2815b45d..602b631b92 100644 --- a/linux-user/signal.c +++ b/linux-user/signal.c @@ -236,7 +236,7 @@ int do_sigprocmask(int how, const sigset_t *set, sigset_t *oldset) return 0; } -#if !defined(TARGET_OPENRISC) && !defined(TARGET_NIOS2) +#if !defined(TARGET_NIOS2) /* Just set the guest's signal mask to the specified value; the * caller is assumed to have called block_signals() already. */ diff --git a/target/openrisc/cpu.c b/target/openrisc/cpu.c index e01ce9ed1c..fb7cb5c507 100644 --- a/target/openrisc/cpu.c +++ b/target/openrisc/cpu.c @@ -27,6 +27,7 @@ static void openrisc_cpu_set_pc(CPUState *cs, vaddr value) OpenRISCCPU *cpu = OPENRISC_CPU(cs); cpu->env.pc = value; + cpu->env.dflag = 0; } static bool openrisc_cpu_has_work(CPUState *cs)