linux-user/loongarch64/signal.c - qemu - Git at Google

 /* 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"
 #include "target/loongarch/vec.h"
 #include "vdso-asmoffset.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);
 };

 QEMU_BUILD_BUG_ON(sizeof(struct target_sigcontext) != sizeof_sigcontext);
 QEMU_BUILD_BUG_ON(offsetof(struct target_sigcontext, sc_pc)
                   != offsetof_sigcontext_pc);
 QEMU_BUILD_BUG_ON(offsetof(struct target_sigcontext, sc_regs)
                   != offsetof_sigcontext_gr);

 #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);

 QEMU_BUILD_BUG_ON(offsetof(struct target_fpu_context, regs)
                   != offsetof_fpucontext_fr);

 #define CONTEXT_INFO_ALIGN      16
 struct target_sctx_info {
     uint32_t magic;
     uint32_t size;
     uint64_t padding;
 } QEMU_ALIGNED(CONTEXT_INFO_ALIGN);

 QEMU_BUILD_BUG_ON(sizeof(struct target_sctx_info) != sizeof_sctx_info);

 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;
 };

 QEMU_BUILD_BUG_ON(sizeof(struct target_rt_sigframe)
                   != sizeof_rt_sigframe);
 QEMU_BUILD_BUG_ON(offsetof(struct target_rt_sigframe, rs_uc.tuc_mcontext)
                   != offsetof_sigcontext);

 /*
  * 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;
 };

 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].vreg.D(0), &fpu_ctx->regs[i]);
     }
     __put_user(read_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].vreg.D(0), &fpu_ctx->regs[i]);
         }
         __get_user(fcc, &fpu_ctx->fcc);
         write_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);
 }
	/* 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"
	#include "target/loongarch/vec.h"
	#include "vdso-asmoffset.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);
	};

	QEMU_BUILD_BUG_ON(sizeof(struct target_sigcontext) != sizeof_sigcontext);
	QEMU_BUILD_BUG_ON(offsetof(struct target_sigcontext, sc_pc)
	!= offsetof_sigcontext_pc);
	QEMU_BUILD_BUG_ON(offsetof(struct target_sigcontext, sc_regs)
	!= offsetof_sigcontext_gr);

	#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);

	QEMU_BUILD_BUG_ON(offsetof(struct target_fpu_context, regs)
	!= offsetof_fpucontext_fr);

	#define CONTEXT_INFO_ALIGN 16
	struct target_sctx_info {
	uint32_t magic;
	uint32_t size;
	uint64_t padding;
	} QEMU_ALIGNED(CONTEXT_INFO_ALIGN);

	QEMU_BUILD_BUG_ON(sizeof(struct target_sctx_info) != sizeof_sctx_info);

	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;
	};

	QEMU_BUILD_BUG_ON(sizeof(struct target_rt_sigframe)
	!= sizeof_rt_sigframe);
	QEMU_BUILD_BUG_ON(offsetof(struct target_rt_sigframe, rs_uc.tuc_mcontext)
	!= offsetof_sigcontext);

	/*
	* 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;
	};

	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].vreg.D(0), &fpu_ctx->regs[i]);
	}
	__put_user(read_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].vreg.D(0), &fpu_ctx->regs[i]);
	}
	__get_user(fcc, &fpu_ctx->fcc);
	write_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);
	}