diff options
Diffstat (limited to 'linux-user/riscv/signal.c')
| -rw-r--r-- | linux-user/riscv/signal.c | 209 |
1 files changed, 209 insertions, 0 deletions
diff --git a/linux-user/riscv/signal.c b/linux-user/riscv/signal.c new file mode 100644 index 000000000..a0f9542ce --- /dev/null +++ b/linux-user/riscv/signal.c @@ -0,0 +1,209 @@ +/* + * 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 "user-internals.h" +#include "signal-common.h" +#include "linux-user/trace.h" + +/* 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; + target_sigset_t uc_sigmask; + uint8_t __unused[1024 / 8 - sizeof(target_sigset_t)]; + struct target_sigcontext uc_mcontext QEMU_ALIGNED(16); +}; + +struct target_rt_sigframe { + 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 = get_sp_from_cpustate(regs); + + /* 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 (on_sig_stack(sp) && !likely(on_sig_stack(sp - framesize))) { + return -1L; + } + + /* This is the X/Open sanctioned signal stack switching. */ + sp = target_sigsp(sp, ka) - framesize; + + /* XXX: kernel aligns with 0xf ? */ + sp &= ~3UL; /* align sp on 4-byte boundary */ + + 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 = riscv_csr_read(env, CSR_FCSR); + __put_user(fcsr, &sc->fcsr); +} + +static void setup_ucontext(struct target_ucontext *uc, + CPURISCVState *env, target_sigset_t *set) +{ + __put_user(0, &(uc->uc_flags)); + __put_user(0, &(uc->uc_link)); + + target_save_altstack(&uc->uc_stack, env); + + 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); +} + +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); + + 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] = default_rt_sigreturn; + + 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); + riscv_csr_write(env, CSR_FCSR, 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); + target_restore_altstack(&frame->uc.uc_stack, env); + + 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; +} + +void setup_sigtramp(abi_ulong sigtramp_page) +{ + uint32_t *tramp = lock_user(VERIFY_WRITE, sigtramp_page, 8, 0); + assert(tramp != NULL); + + __put_user(0x08b00893, tramp + 0); /* li a7, 139 = __NR_rt_sigreturn */ + __put_user(0x00000073, tramp + 1); /* ecall */ + + default_rt_sigreturn = sigtramp_page; + unlock_user(tramp, sigtramp_page, 8); +} |