From 9d5cd6587a70d613087a284763d44ff6fe798149 Mon Sep 17 00:00:00 2001 From: Song Gao Date: Fri, 24 Jun 2022 11:10:38 +0800 Subject: [PATCH] linux-user: Add LoongArch signal support Signed-off-by: Song Gao Signed-off-by: Xiaojuan Yang Message-Id: <20220624031049.1716097-3-gaosong@loongson.cn> [rth: Rework extctx frame allocation and locking; Properly read/write fcc from signal frame.] Signed-off-by: Richard Henderson --- linux-user/loongarch64/signal.c | 335 +++++++++++++++++++++++++ linux-user/loongarch64/target_signal.h | 13 + 2 files changed, 348 insertions(+) create mode 100644 linux-user/loongarch64/signal.c create mode 100644 linux-user/loongarch64/target_signal.h diff --git a/linux-user/loongarch64/signal.c b/linux-user/loongarch64/signal.c new file mode 100644 index 0000000000..65fd5f3857 --- /dev/null +++ b/linux-user/loongarch64/signal.c @@ -0,0 +1,335 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * LoongArch emulation of Linux signals + * + * Copyright (c) 2021 Loongson Technology Corporation Limited + */ + +#include "qemu/osdep.h" +#include "qemu.h" +#include "user-internals.h" +#include "signal-common.h" +#include "linux-user/trace.h" + +#include "target/loongarch/internals.h" + +/* FP context was used */ +#define SC_USED_FP (1 << 0) + +struct target_sigcontext { + uint64_t sc_pc; + uint64_t sc_regs[32]; + uint32_t sc_flags; + uint64_t sc_extcontext[0] QEMU_ALIGNED(16); +}; + + +#define FPU_CTX_MAGIC 0x46505501 +#define FPU_CTX_ALIGN 8 +struct target_fpu_context { + uint64_t regs[32]; + uint64_t fcc; + uint32_t fcsr; +} QEMU_ALIGNED(FPU_CTX_ALIGN); + +#define CONTEXT_INFO_ALIGN 16 +struct target_sctx_info { + uint32_t magic; + uint32_t size; + uint64_t padding; +} QEMU_ALIGNED(CONTEXT_INFO_ALIGN); + +struct target_ucontext { + abi_ulong tuc_flags; + abi_ptr tuc_link; + target_stack_t tuc_stack; + target_sigset_t tuc_sigmask; + uint8_t __unused[1024 / 8 - sizeof(target_sigset_t)]; + struct target_sigcontext tuc_mcontext; +}; + +struct target_rt_sigframe { + struct target_siginfo rs_info; + struct target_ucontext rs_uc; +}; + +/* + * These two structures are not present in guest memory, are private + * to the signal implementation, but are largely copied from the + * kernel's signal implementation. + */ +struct ctx_layout { + void *haddr; + abi_ptr gaddr; + unsigned int size; +}; + +struct extctx_layout { + unsigned int size; + unsigned int flags; + struct ctx_layout fpu; + struct ctx_layout end; +}; + +/* The kernel's sc_save_fcc macro is a sequence of MOVCF2GR+BSTRINS. */ +static uint64_t read_all_fcc(CPULoongArchState *env) +{ + uint64_t ret = 0; + + for (int i = 0; i < 8; ++i) { + ret |= (uint64_t)env->cf[i] << (i * 8); + } + + return ret; +} + +/* The kernel's sc_restore_fcc macro is a sequence of BSTRPICK+MOVGR2CF. */ +static void write_all_fcc(CPULoongArchState *env, uint64_t val) +{ + for (int i = 0; i < 8; ++i) { + env->cf[i] = (val >> (i * 8)) & 1; + } +} + +static abi_ptr extframe_alloc(struct extctx_layout *extctx, + struct ctx_layout *sctx, unsigned size, + unsigned align, abi_ptr orig_sp) +{ + abi_ptr sp = orig_sp; + + sp -= sizeof(struct target_sctx_info) + size; + align = MAX(align, CONTEXT_INFO_ALIGN); + sp = ROUND_DOWN(sp, align); + sctx->gaddr = sp; + + size = orig_sp - sp; + sctx->size = size; + extctx->size += size; + + return sp; +} + +static abi_ptr setup_extcontext(struct extctx_layout *extctx, abi_ptr sp) +{ + memset(extctx, 0, sizeof(struct extctx_layout)); + + /* Grow down, alloc "end" context info first. */ + sp = extframe_alloc(extctx, &extctx->end, 0, CONTEXT_INFO_ALIGN, sp); + + /* For qemu, there is no lazy fp context switch, so fp always present. */ + extctx->flags = SC_USED_FP; + sp = extframe_alloc(extctx, &extctx->fpu, + sizeof(struct target_rt_sigframe), FPU_CTX_ALIGN, sp); + + return sp; +} + +static void setup_sigframe(CPULoongArchState *env, + struct target_sigcontext *sc, + struct extctx_layout *extctx) +{ + struct target_sctx_info *info; + struct target_fpu_context *fpu_ctx; + int i; + + __put_user(extctx->flags, &sc->sc_flags); + __put_user(env->pc, &sc->sc_pc); + __put_user(0, &sc->sc_regs[0]); + for (i = 1; i < 32; ++i) { + __put_user(env->gpr[i], &sc->sc_regs[i]); + } + + /* + * Set fpu context + */ + info = extctx->fpu.haddr; + __put_user(FPU_CTX_MAGIC, &info->magic); + __put_user(extctx->fpu.size, &info->size); + + fpu_ctx = (struct target_fpu_context *)(info + 1); + for (i = 0; i < 32; ++i) { + __put_user(env->fpr[i], &fpu_ctx->regs[i]); + } + __put_user(read_all_fcc(env), &fpu_ctx->fcc); + __put_user(env->fcsr0, &fpu_ctx->fcsr); + + /* + * Set end context + */ + info = extctx->end.haddr; + __put_user(0, &info->magic); + __put_user(extctx->end.size, &info->size); +} + +static bool parse_extcontext(struct extctx_layout *extctx, abi_ptr frame) +{ + memset(extctx, 0, sizeof(*extctx)); + + while (1) { + uint32_t magic, size; + + if (get_user_u32(magic, frame) || get_user_u32(size, frame + 4)) { + return false; + } + + switch (magic) { + case 0: /* END */ + extctx->end.gaddr = frame; + extctx->end.size = size; + extctx->size += size; + return true; + + case FPU_CTX_MAGIC: + if (size < (sizeof(struct target_sctx_info) + + sizeof(struct target_fpu_context))) { + return false; + } + extctx->fpu.gaddr = frame; + extctx->fpu.size = size; + extctx->size += size; + break; + default: + return false; + } + + frame += size; + } +} + +static void restore_sigframe(CPULoongArchState *env, + struct target_sigcontext *sc, + struct extctx_layout *extctx) +{ + int i; + + __get_user(env->pc, &sc->sc_pc); + for (i = 1; i < 32; ++i) { + __get_user(env->gpr[i], &sc->sc_regs[i]); + } + + if (extctx->fpu.haddr) { + struct target_fpu_context *fpu_ctx = + extctx->fpu.haddr + sizeof(struct target_sctx_info); + uint64_t fcc; + + for (i = 0; i < 32; ++i) { + __get_user(env->fpr[i], &fpu_ctx->regs[i]); + } + __get_user(fcc, &fpu_ctx->fcc); + write_all_fcc(env, fcc); + __get_user(env->fcsr0, &fpu_ctx->fcsr); + restore_fp_status(env); + } +} + +/* + * Determine which stack to use. + */ +static abi_ptr get_sigframe(struct target_sigaction *ka, + CPULoongArchState *env, + struct extctx_layout *extctx) +{ + abi_ulong sp; + + sp = target_sigsp(get_sp_from_cpustate(env), ka); + sp = ROUND_DOWN(sp, 16); + sp = setup_extcontext(extctx, sp); + sp -= sizeof(struct target_rt_sigframe); + + assert(QEMU_IS_ALIGNED(sp, 16)); + + return sp; +} + +void setup_rt_frame(int sig, struct target_sigaction *ka, + target_siginfo_t *info, + target_sigset_t *set, CPULoongArchState *env) +{ + struct target_rt_sigframe *frame; + struct extctx_layout extctx; + abi_ptr frame_addr; + int i; + + frame_addr = get_sigframe(ka, env, &extctx); + trace_user_setup_rt_frame(env, frame_addr); + + frame = lock_user(VERIFY_WRITE, frame_addr, + sizeof(*frame) + extctx.size, 0); + if (!frame) { + force_sigsegv(sig); + return; + } + extctx.fpu.haddr = (void *)frame + (extctx.fpu.gaddr - frame_addr); + extctx.end.haddr = (void *)frame + (extctx.end.gaddr - frame_addr); + + tswap_siginfo(&frame->rs_info, info); + + __put_user(0, &frame->rs_uc.tuc_flags); + __put_user(0, &frame->rs_uc.tuc_link); + target_save_altstack(&frame->rs_uc.tuc_stack, env); + + setup_sigframe(env, &frame->rs_uc.tuc_mcontext, &extctx); + + for (i = 0; i < TARGET_NSIG_WORDS; i++) { + __put_user(set->sig[i], &frame->rs_uc.tuc_sigmask.sig[i]); + } + + env->gpr[4] = sig; + env->gpr[5] = frame_addr + offsetof(struct target_rt_sigframe, rs_info); + env->gpr[6] = frame_addr + offsetof(struct target_rt_sigframe, rs_uc); + env->gpr[3] = frame_addr; + env->gpr[1] = default_rt_sigreturn; + + env->pc = ka->_sa_handler; + unlock_user(frame, frame_addr, sizeof(*frame) + extctx.size); +} + +long do_rt_sigreturn(CPULoongArchState *env) +{ + struct target_rt_sigframe *frame; + struct extctx_layout extctx; + abi_ulong frame_addr; + sigset_t blocked; + + frame_addr = env->gpr[3]; + trace_user_do_rt_sigreturn(env, frame_addr); + + if (!parse_extcontext(&extctx, frame_addr + sizeof(*frame))) { + goto badframe; + } + + frame = lock_user(VERIFY_READ, frame_addr, + sizeof(*frame) + extctx.size, 1); + if (!frame) { + goto badframe; + } + if (extctx.fpu.gaddr) { + extctx.fpu.haddr = (void *)frame + (extctx.fpu.gaddr - frame_addr); + } + + target_to_host_sigset(&blocked, &frame->rs_uc.tuc_sigmask); + set_sigmask(&blocked); + + restore_sigframe(env, &frame->rs_uc.tuc_mcontext, &extctx); + + target_restore_altstack(&frame->rs_uc.tuc_stack, env); + + unlock_user(frame, frame_addr, 0); + return -QEMU_ESIGRETURN; + + badframe: + force_sig(TARGET_SIGSEGV); + return -QEMU_ESIGRETURN; +} + +void setup_sigtramp(abi_ulong sigtramp_page) +{ + uint32_t *tramp = lock_user(VERIFY_WRITE, sigtramp_page, 8, 0); + assert(tramp != NULL); + + __put_user(0x03822c0b, tramp + 0); /* ori a7, zero, 0x8b */ + __put_user(0x002b0000, tramp + 1); /* syscall 0 */ + + default_rt_sigreturn = sigtramp_page; + unlock_user(tramp, sigtramp_page, 8); +} diff --git a/linux-user/loongarch64/target_signal.h b/linux-user/loongarch64/target_signal.h new file mode 100644 index 0000000000..ad3aaffcb4 --- /dev/null +++ b/linux-user/loongarch64/target_signal.h @@ -0,0 +1,13 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * Copyright (c) 2021 Loongson Technology Corporation Limited + */ + +#ifndef LOONGARCH_TARGET_SIGNAL_H +#define LOONGARCH_TARGET_SIGNAL_H + +#include "../generic/signal.h" + +#define TARGET_ARCH_HAS_SIGTRAMP_PAGE 1 + +#endif /* LOONGARCH_TARGET_SIGNAL_H */