[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[PATCH v2 17/20] hurd: Add an AArch64 signal implementation
|
From: |
Sergey Bugaev |
|
Subject: |
[PATCH v2 17/20] hurd: Add an AArch64 signal implementation |
|
Date: |
Sat, 23 Mar 2024 20:32:58 +0300 |
Signed-off-by: Sergey Bugaev <bugaevc@gmail.com>
---
sysdeps/mach/hurd/aarch64/Makefile | 4 +
sysdeps/mach/hurd/aarch64/bits/sigcontext.h | 96 ++++++
sysdeps/mach/hurd/aarch64/exc2signal.c | 149 +++++++++
sysdeps/mach/hurd/aarch64/intr-msg.h | 123 ++++++++
sysdeps/mach/hurd/aarch64/sigreturn.c | 127 ++++++++
sysdeps/mach/hurd/aarch64/trampoline.c | 325 ++++++++++++++++++++
6 files changed, 824 insertions(+)
create mode 100644 sysdeps/mach/hurd/aarch64/bits/sigcontext.h
create mode 100644 sysdeps/mach/hurd/aarch64/exc2signal.c
create mode 100644 sysdeps/mach/hurd/aarch64/intr-msg.h
create mode 100644 sysdeps/mach/hurd/aarch64/sigreturn.c
create mode 100644 sysdeps/mach/hurd/aarch64/trampoline.c
diff --git a/sysdeps/mach/hurd/aarch64/Makefile
b/sysdeps/mach/hurd/aarch64/Makefile
index 9210d436..6cc831d6 100644
--- a/sysdeps/mach/hurd/aarch64/Makefile
+++ b/sysdeps/mach/hurd/aarch64/Makefile
@@ -22,3 +22,7 @@ endif
ifeq ($(subdir),setjmp)
gen-as-const-headers += signal-defines.sym
endif
+
+ifeq ($(subdir),signal)
+CFLAGS-sigreturn.c += -mgeneral-regs-only
+endif
diff --git a/sysdeps/mach/hurd/aarch64/bits/sigcontext.h
b/sysdeps/mach/hurd/aarch64/bits/sigcontext.h
new file mode 100644
index 00000000..163523fa
--- /dev/null
+++ b/sysdeps/mach/hurd/aarch64/bits/sigcontext.h
@@ -0,0 +1,96 @@
+/* Machine-dependent signal context structure for GNU Hurd. AArch64 version.
+ Copyright (C) 1991-2024 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library 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
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <https://www.gnu.org/licenses/>. */
+
+#ifndef _BITS_SIGCONTEXT_H
+#define _BITS_SIGCONTEXT_H 1
+
+#if !defined _SIGNAL_H && !defined _SYS_UCONTEXT_H
+# error "Never use <bits/sigcontext.h> directly; include <signal.h> instead."
+#endif
+
+/* Signal handlers are actually called:
+ void handler (int sig, int code, struct sigcontext *scp); */
+
+#include <bits/types/__sigset_t.h>
+#include <mach/machine/fp_reg.h>
+
+/* State of this thread when the signal was taken. */
+struct sigcontext
+ {
+ /* These first members are machine-independent. */
+
+ int sc_onstack; /* Nonzero if running on sigstack. */
+ __sigset_t sc_mask; /* Blocked signals to restore. */
+
+ /* MiG reply port this thread is using. */
+ unsigned int sc_reply_port;
+
+ /* Port this thread is doing an interruptible RPC on. */
+ unsigned int sc_intr_port;
+
+ /* Error code associated with this signal (interpreted as `error_t'). */
+ int sc_error;
+
+ /* Make sure the below members are properly aligned, and not packed
+ together with sc_error -- otherwise the layout won't match that of
+ aarch64_thread_state. */
+ int sc_pad1;
+
+ /* All following members are machine-dependent. The rest of this
+ structure is written to be laid out identically to:
+ {
+ struct aarch64_thread_state basic;
+ struct aarch64_float_state fpu;
+ }
+ trampoline.c knows this, so it must be changed if this changes. */
+
+#define sc_aarch64_thread_state sc_x[0] /* Beginning of correspondence. */
+ long sc_x[31];
+ long sc_sp;
+ long sc_pc;
+ long sc_tpidr_el0;
+ long sc_cpsr;
+
+#define sc_aarch64_float_state sc_v[0]
+ __int128_t sc_v[32];
+ long sc_fpsr;
+ long sc_fpcr;
+ };
+
+/* Traditional BSD names for some members. */
+#define sc_fp sc_x[29] /* Frame pointer. */
+#define sc_ps sc_cpsr
+
+
+/* The deprecated sigcode values below are passed as an extra, non-portable
+ argument to regular signal handlers. You should use SA_SIGINFO handlers
+ instead, which use the standard POSIX signal codes. */
+
+/* Codes for SIGFPE. */
+#define FPE_INTOVF_TRAP 0x1 /* integer overflow */
+#define FPE_INTDIV_FAULT 0x2 /* integer divide by zero */
+#define FPE_FLTOVF_FAULT 0x3 /* floating overflow */
+#define FPE_FLTDIV_FAULT 0x4 /* floating divide by zero */
+#define FPE_FLTUND_FAULT 0x5 /* floating underflow */
+#define FPE_SUBRNG_FAULT 0x7 /* BOUNDS instruction failed */
+#define FPE_FLTDNR_FAULT 0x8 /* denormalized operand */
+#define FPE_FLTINX_FAULT 0x9 /* floating loss of precision */
+#define FPE_EMERR_FAULT 0xa /* mysterious emulation error 33 */
+#define FPE_EMBND_FAULT 0xb /* emulation BOUNDS instruction
failed */
+
+#endif /* bits/sigcontext.h */
diff --git a/sysdeps/mach/hurd/aarch64/exc2signal.c
b/sysdeps/mach/hurd/aarch64/exc2signal.c
new file mode 100644
index 00000000..7027bbf7
--- /dev/null
+++ b/sysdeps/mach/hurd/aarch64/exc2signal.c
@@ -0,0 +1,149 @@
+/* Translate Mach exception codes into signal numbers. AArch64 version.
+ Copyright (C) 1991-2024 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library 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
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <https://www.gnu.org/licenses/>. */
+
+#include <hurd.h>
+#include <hurd/signal.h>
+#include <mach/exception.h>
+
+/* Translate the Mach exception codes, as received in an `exception_raise' RPC,
+ into a signal number and signal subcode. */
+
+static void
+exception2signal (struct hurd_signal_detail *detail, int *signo, int posix)
+{
+ detail->error = 0;
+
+ switch (detail->exc)
+ {
+ default:
+ *signo = SIGIOT;
+ detail->code = detail->exc;
+ break;
+
+ case EXC_BAD_ACCESS:
+ switch (detail->exc_code)
+ {
+ case KERN_INVALID_ADDRESS:
+ case KERN_MEMORY_FAILURE:
+ *signo = SIGSEGV;
+ detail->code = posix ? SEGV_MAPERR : detail->exc_subcode;
+ break;
+
+ case KERN_PROTECTION_FAILURE:
+ case KERN_WRITE_PROTECTION_FAILURE:
+ *signo = SIGSEGV;
+ detail->code = posix ? SEGV_ACCERR : detail->exc_subcode;
+ break;
+
+ case EXC_AARCH64_MTE:
+ *signo = SIGSEGV;
+ /* TODO: Should be SEGV_MTESERR */
+ detail->code = posix ? SEGV_ACCERR : detail->exc_subcode;
+ break;
+
+ case EXC_AARCH64_BTI:
+ *signo = SIGILL;
+ /* XXX: Consider adopting ILL_BTCFI from OpenBSD. */
+ /* XXX: exc_subcode / signal code contains BTYPE */
+ detail->code = posix ? ILL_ILLOPN : detail->exc_subcode;
+ break;
+
+ case EXC_AARCH64_AL:
+ case EXC_AARCH64_AL_PC:
+ case EXC_AARCH64_AL_SP:
+ *signo = SIGBUS;
+ detail->code = posix ? BUS_ADRALN : detail->exc_subcode;
+ break;
+
+ default:
+ *signo = SIGBUS;
+ detail->code = posix ? BUS_ADRERR : detail->exc_subcode;
+ break;
+ }
+ detail->error = detail->exc_code;
+ break;
+
+ case EXC_BAD_INSTRUCTION:
+ *signo = SIGILL;
+ switch (detail->exc_code)
+ {
+ case EXC_AARCH64_SVC:
+ detail->code = posix ? ILL_ILLTRP : 0;
+ break;
+
+ default:
+ detail->code = posix ? ILL_ILLOPC : 0;
+ break;
+ }
+ break;
+
+ case EXC_ARITHMETIC:
+ *signo = SIGFPE;
+ switch (detail->exc_code)
+ {
+ case EXC_AARCH64_IDF:
+ detail->code = posix ? FPE_FLTIDO : 0;
+ break;
+ case EXC_AARCH64_IXF:
+ detail->code = posix ? FPE_FLTRES : FPE_FLTINX_FAULT;
+ break;
+ case EXC_AARCH64_UFF:
+ detail->code = posix ? FPE_FLTUND : FPE_FLTDNR_FAULT;
+ break;
+ case EXC_AARCH64_OFF:
+ detail->code = posix ? FPE_FLTOVF : FPE_FLTOVF_FAULT;
+ break;
+ case EXC_AARCH64_DZF:
+ detail->code = posix ? FPE_FLTDIV : FPE_FLTDIV_FAULT;
+ break;
+ case EXC_AARCH64_IOF:
+ /* NB: We used to send SIGILL here but we can't distinguish
+ POSIX vs. legacy with respect to what signal we send. */
+ detail->code = posix ? FPE_FLTINV : 0 /*ILL_FPEOPR_FAULT*/;
+ break;
+ default:
+ detail->code = 0;
+ }
+ break;
+
+ case EXC_EMULATION:
+ case EXC_SOFTWARE:
+ *signo = SIGEMT;
+ detail->code = 0;
+ break;
+
+
+ case EXC_BREAKPOINT:
+ *signo = SIGTRAP;
+ detail->code = posix ? TRAP_BRKPT : 0;
+ break;
+ }
+}
+libc_hidden_def (_hurd_exception2signal)
+
+void
+_hurd_exception2signal (struct hurd_signal_detail *detail, int *signo)
+{
+ exception2signal (detail, signo, 1);
+}
+
+void
+_hurd_exception2signal_legacy (struct hurd_signal_detail *detail, int *signo)
+{
+ exception2signal (detail, signo, 0);
+}
diff --git a/sysdeps/mach/hurd/aarch64/intr-msg.h
b/sysdeps/mach/hurd/aarch64/intr-msg.h
new file mode 100644
index 00000000..b511d7d7
--- /dev/null
+++ b/sysdeps/mach/hurd/aarch64/intr-msg.h
@@ -0,0 +1,123 @@
+/* Machine-dependent details of interruptible RPC messaging. AArch64 version.
+ Copyright (C) 1995-2024 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library 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
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <https://www.gnu.org/licenses/>. */
+
+
+/* Note that we must mark OPTION and TIMEOUT as outputs of this operation,
+ to indicate that the signal thread might mutate them as part
+ of sending us to a signal handler. */
+
+#define INTR_MSG_TRAP(msg, option, send_size, rcv_size, rcv_name, timeout,
notify, cancel_p, intr_port_p) \
+({ \
+ register uintptr_t /* error_t */ err asm ("x0"); \
+ register uintptr_t option_x1 asm ("x1") = option; \
+ register uintptr_t send_size_x2 asm ("x2") = send_size; \
+ register uintptr_t rcv_size_x3 asm ("x3") = rcv_size;
\
+ register uintptr_t rcv_name_x4 asm ("x4") = rcv_name;
\
+ register uintptr_t timeout_x5 asm ("x5") = timeout; \
+ register uintptr_t notify_x6 asm ("x6") = notify; \
+ register void *msg_x9 asm ("x9") = msg; /* used by trampoline.c */ \
+ asm volatile ("\n" \
+ ".globl _hurd_intr_rpc_msg_about_to\n" \
+ ".globl _hurd_intr_rpc_msg_setup_done\n"
\
+ ".globl _hurd_intr_rpc_msg_in_trap\n" \
+ /* Clear x0 before we do the check for cancel below. This is to
+ detect x0 being set to non-zero (actually MACH_SEND_INTERRUPTED)
+ from the outside (namely, _hurdsig_abort_rpcs), which signals us
+ to skip the trap we were about to enter. */ \
+ " mov %[err], #0\n" \
+ "_hurd_intr_rpc_msg_about_to:\n"
\
+ /* We need to make a last check of cancel, in case we got interrupted
+ right before _hurd_intr_rpc_msg_about_to. */
\
+ " ldr w8, %[cancel]\n" \
+ " cbz w8, _hurd_intr_rpc_msg_do\n" \
+ /* We got interrupted, note so and return EINTR. */ \
+ " str wzr, %[intr_port]\n" \
+ " mov %[err], %[eintr_lo]\n" \
+ " movk %[err], %[eintr_hi], lsl 16\n" \
+ " b _hurd_intr_rpc_msg_sp_restored\n" \
+ "_hurd_intr_rpc_msg_do:\n" \
+ /* Ok, prepare the mach_msg_trap arguments. We pass all the 7 args
+ in registers. */ \
+ "_hurd_intr_rpc_msg_setup_done:\n" \
+ /* From here on, it is safe to make us jump over the syscall. Now
+ check if we have been told to skip the syscall while running
+ the above. */ \
+ " cbnz %[err], _hurd_intr_rpc_msg_in_trap\n" \
+ /* Do the actual syscall. */ \
+ " mov %[err], %[msg]\n" \
+ " mov x8, #-25\n" \
+ "_hurd_intr_rpc_msg_do_trap:\n" \
+ " svc #0\n" /* status in %[err] */ \
+ "_hurd_intr_rpc_msg_in_trap:\n" \
+ "_hurd_intr_rpc_msg_sp_restored:\n" \
+ : [err] "=r" (err), "+r" (option_x1), \
+ [intr_port] "=m" (*intr_port_p), \
+ "+r" (timeout_x5) \
+ : [msg] "r" (msg_x9), "r" (send_size_x2), "r" (rcv_size_x3), \
+ "r" (rcv_name_x4), "r" (notify_x6), \
+ [cancel] "m" (*cancel_p), \
+ [eintr_lo] "i" (EINTR & 0xffff), [eintr_hi] "i" (EINTR >> 16)); \
+ option = option_x1; \
+ timeout = timeout_x5;
\
+ err; \
+})
+
+#include "hurdfault.h"
+
+/* This cannot be an inline function because it calls setjmp. */
+#define SYSCALL_EXAMINE(state, callno) \
+({ \
+ int result; \
+ unsigned int *p = (unsigned int *) (state)->pc - 4; \
+ if (_hurdsig_catch_memory_fault (p)) \
+ return 0; \
+ if (result = (*p == 0xd4000001)) \
+ /* The PC is just after a "svc #0" instruction.
+ This is a system call in progress; x8 holds the call number. */
\
+ *(callno) = (state)->x[8]; \
+ _hurdsig_end_catch_fault (); \
+ result; \
+})
+
+
+/* This cannot be an inline function because it calls setjmp. */
+#define MSG_EXAMINE(state, msgid, rcvname, send_name, opt, tmout) \
+({ \
+ int ret = 0; \
+ const struct machine_thread_state *s = (state); \
+ const mach_msg_header_t *msg = (const void *) s->x[0]; \
+ *(opt) = s->x[1]; \
+ *(rcvname) = s->x[4];
\
+ *(tmout) = s->x[5]; \
+ if (msg == 0)
\
+ { \
+ *(send_name) = MACH_PORT_NULL; \
+ *(msgid) = 0; \
+ } \
+ else \
+ { \
+ ret = _hurdsig_catch_memory_fault (msg) ? -1 : 0;
\
+ if (ret == 0) \
+ { \
+ *(send_name) = msg->msgh_remote_port;
\
+ *(msgid) = msg->msgh_id; \
+ _hurdsig_end_catch_fault (); \
+ } \
+ } \
+ ret; \
+})
diff --git a/sysdeps/mach/hurd/aarch64/sigreturn.c
b/sysdeps/mach/hurd/aarch64/sigreturn.c
new file mode 100644
index 00000000..c58b9c49
--- /dev/null
+++ b/sysdeps/mach/hurd/aarch64/sigreturn.c
@@ -0,0 +1,127 @@
+/* Copyright (C) 1991-2024 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library 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
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <https://www.gnu.org/licenses/>. */
+
+#include <hurd.h>
+#include <hurd/signal.h>
+#include <hurd/msg.h>
+#include <stdlib.h>
+
+/* This is run on the thread stack after restoring it, to be able to
+ unlock SS off sigstack. */
+void
+__sigreturn2 (struct sigcontext *scp,
+ struct hurd_sigstate *ss)
+{
+ error_t err;
+ mach_port_t reply_port;
+ _hurd_sigstate_unlock (ss);
+
+ /* Destroy the MiG reply port used by the signal handler, and restore the
+ reply port in use by the thread when interrupted.
+
+ We cannot use the original reply port for our RPCs that we do here, since
+ we could unexpectedly receive/consume a reply message meant for the user
+ (in particular, msg_sig_post_reply), and also since we would deallocate
+ the port if *our* RPC fails, which we don't want to do since the user
+ still has the old name. And so, temporarily set MACH_PORT_DEAD as our
+ reply name, and make sure destroying the port is the very last RPC we
+ do. */
+ reply_port = THREAD_GETMEM (THREAD_SELF, reply_port);
+ THREAD_SETMEM (THREAD_SELF, reply_port, MACH_PORT_DEAD);
+ if (__glibc_likely (MACH_PORT_VALID (reply_port)))
+ (void) __mach_port_mod_refs (__mach_task_self (), reply_port,
+ MACH_PORT_RIGHT_RECEIVE, -1);
+ THREAD_SETMEM (THREAD_SELF, reply_port, scp->sc_reply_port);
+
+ /* Restore thread state. */
+ err = __thread_set_self_state (AARCH64_FLOAT_STATE,
+ (thread_state_t) &scp->sc_aarch64_float_state,
+ AARCH64_FLOAT_STATE_COUNT);
+ assert_perror (err);
+ err = __thread_set_self_state (AARCH64_THREAD_STATE,
+ (thread_state_t) &scp->sc_aarch64_thread_state,
+ AARCH64_THREAD_STATE_COUNT);
+ assert_perror (err);
+ __builtin_unreachable ();
+}
+
+int
+__sigreturn (struct sigcontext *scp)
+{
+ struct hurd_sigstate *ss;
+ struct hurd_userlink *link = (void *) &scp[1];
+ uintptr_t usp;
+
+ if (__glibc_unlikely (scp == NULL || (scp->sc_mask & _SIG_CANT_MASK)))
+ return __hurd_fail (EINVAL);
+
+ ss = _hurd_self_sigstate ();
+ _hurd_sigstate_lock (ss);
+
+ /* Remove the link on the `active resources' chain added by
+ _hurd_setup_sighandler. Its purpose was to make sure
+ that we got called; now we have, it is done. */
+ _hurd_userlink_unlink (link);
+
+ /* Restore the set of blocked signals, and the intr_port slot. */
+ ss->blocked = scp->sc_mask;
+ ss->intr_port = scp->sc_intr_port;
+
+ /* Check for pending signals that were blocked by the old set. */
+ if (_hurd_sigstate_pending (ss) & ~ss->blocked)
+ {
+ /* There are pending signals that just became unblocked. Wake up the
+ signal thread to deliver them. But first, squirrel away SCP where
+ the signal thread will notice it if it runs another handler, and
+ arrange to have us called over again in the new reality. */
+ ss->context = scp;
+ _hurd_sigstate_unlock (ss);
+ __msg_sig_post (_hurd_msgport, 0, 0, __mach_task_self ());
+ /* If a pending signal was handled, sig_post never returned.
+ If it did return, the pending signal didn't run a handler;
+ proceed as usual. */
+ _hurd_sigstate_lock (ss);
+ ss->context = NULL;
+ }
+
+ if (scp->sc_onstack)
+ ss->sigaltstack.ss_flags &= ~SS_ONSTACK;
+
+ /* Copy the signal context onto the user's stack, to be able to release the
+ altstack (by unlocking sigstate). Note that unless an altstack is used,
+ the sigcontext will itself be located on the user's stack, so we may well
+ be overwriting it here (or later in __sigreturn2). */
+
+ usp = ALIGN_DOWN(scp->sc_sp - sizeof (struct sigcontext), 16);
+ memmove ((void *) usp, scp, sizeof (struct sigcontext));
+
+ /* Switch to the user's stack that we have just prepared, and call
+ __sigreturn2. Clobber "memory" to make sure GCC flushes the stack
+ setup to actual memory. */
+ {
+ register uintptr_t usp_x0 asm("x0") = usp;
+ register struct hurd_sigstate *ss_x1 asm("x1") = ss;
+
+ asm volatile ("mov sp, %0\n"
+ "b __sigreturn2"
+ :: "r" (usp_x0), "r" (ss_x1)
+ : "memory");
+ __builtin_unreachable ();
+ }
+}
+
+weak_alias (__sigreturn, sigreturn)
diff --git a/sysdeps/mach/hurd/aarch64/trampoline.c
b/sysdeps/mach/hurd/aarch64/trampoline.c
new file mode 100644
index 00000000..4b301335
--- /dev/null
+++ b/sysdeps/mach/hurd/aarch64/trampoline.c
@@ -0,0 +1,325 @@
+/* Set thread_state for sighandler, and sigcontext to recover. AArch64
version.
+ Copyright (C) 1994-2024 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library 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
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <https://www.gnu.org/licenses/>. */
+
+#include <hurd/signal.h>
+#include <hurd/userlink.h>
+#include <thread_state.h>
+#include <mach/exception.h>
+#include <assert.h>
+#include <errno.h>
+#include "hurdfault.h"
+#include <sys/ucontext.h>
+
+
+/* Fill in a siginfo_t structure for SA_SIGINFO-enabled handlers. */
+static void fill_siginfo (siginfo_t *si, int signo,
+ const struct hurd_signal_detail *detail,
+ const struct machine_thread_all_state *state)
+{
+ si->si_signo = signo;
+ si->si_errno = detail->error;
+ si->si_code = detail->code;
+
+ /* XXX We would need a protocol change for sig_post to include
+ * this information. */
+ si->si_pid = -1;
+ si->si_uid = -1;
+
+ /* Address of the faulting instruction or memory access. */
+ if (detail->exc == EXC_BAD_ACCESS)
+ si->si_addr = (void *) detail->exc_subcode;
+ else
+ si->si_addr = (void *) state->basic.pc;
+
+ /* XXX On SIGCHLD, this should be the exit status of the child
+ * process. We would need a protocol change for the proc server
+ * to send this information along with the signal. */
+ si->si_status = 0;
+
+ si->si_band = 0; /* SIGPOLL is not supported yet. */
+ si->si_value.sival_int = 0; /* sigqueue() is not supported yet. */
+}
+
+/* Fill in a ucontext_t structure SA_SIGINFO-enabled handlers. */
+static void fill_ucontext (ucontext_t *uc, const struct sigcontext *sc)
+{
+ uc->uc_flags = 0;
+ uc->uc_link = NULL;
+ uc->uc_sigmask = sc->sc_mask;
+ uc->uc_stack.ss_sp = (__ptr_t) sc->sc_sp;
+ uc->uc_stack.ss_size = 0;
+ uc->uc_stack.ss_flags = 0;
+
+ memcpy (&uc->uc_mcontext.gregs, &sc->sc_aarch64_thread_state,
+ sizeof (struct aarch64_thread_state));
+ memcpy (&uc->uc_mcontext.fpregs, &sc->sc_aarch64_float_state,
+ sizeof (struct aarch64_float_state));
+}
+
+struct sigcontext *
+_hurd_setup_sighandler (struct hurd_sigstate *ss, const struct sigaction
*action,
+ __sighandler_t handler,
+ int signo, struct hurd_signal_detail *detail,
+ int rpc_wait,
+ struct machine_thread_all_state *state)
+{
+ void trampoline (void) attribute_hidden;
+ void rpc_wait_trampoline (void) attribute_hidden;
+ void *sigsp;
+ struct sigcontext *scp;
+ struct
+ {
+ union
+ {
+ int signo;
+ /* Make sure signo takes up a pointer-sized slot on the stack.
+ (This should already be the case considering the siginfop
+ pointer below, but better be explicit.) */
+ void *_pointer_sized;
+ };
+ union
+ {
+ /* Extra arguments for traditional signal handlers */
+ struct
+ {
+ long int sigcode;
+ struct sigcontext *scp; /* Points to ctx, below. */
+ } legacy;
+
+ /* Extra arguments for SA_SIGINFO handlers */
+ struct
+ {
+ siginfo_t *siginfop; /* Points to siginfo, below. */
+ ucontext_t *uctxp; /* Points to uctx, below. */
+ } posix;
+ };
+
+ void *_pad;
+
+ /* NB: sigreturn assumes link is next to ctx. */
+ struct sigcontext ctx;
+ struct hurd_userlink link;
+ ucontext_t ucontext;
+ siginfo_t siginfo;
+ } *stackframe;
+
+ if (ss->context)
+ {
+ /* We have a previous sigcontext that sigreturn was about
+ to restore when another signal arrived. We will just base
+ our setup on that. */
+ if (! _hurdsig_catch_memory_fault (ss->context))
+ {
+ memcpy (&state->basic, &ss->context->sc_aarch64_thread_state,
+ sizeof (state->basic));
+ memcpy (&state->fpu, &ss->context->sc_aarch64_float_state,
+ sizeof (state->fpu));
+ state->set |= (1 << AARCH64_THREAD_STATE) | (1 <<
AARCH64_FLOAT_STATE);
+ }
+ }
+
+ if (! machine_get_basic_state (ss->thread, state))
+ return NULL;
+
+ if ((action->sa_flags & SA_ONSTACK)
+ && !(ss->sigaltstack.ss_flags & (SS_DISABLE|SS_ONSTACK)))
+ {
+ sigsp = ss->sigaltstack.ss_sp + ss->sigaltstack.ss_size;
+ ss->sigaltstack.ss_flags |= SS_ONSTACK;
+ }
+ else
+ /* No red zone on aarch64-gnu. */
+ sigsp = (void *) state->basic.sp;
+
+ /* Push the arguments to call `trampoline' on the stack.
+ Note that user's SP doesn't strictly have to be 16-aligned, since
+ AArch64 only requires 16-alignment for the stack pointer when
+ making accesses relative to it. */
+ sigsp = PTR_ALIGN_DOWN (sigsp - sizeof (*stackframe), 16);
+ stackframe = sigsp;
+
+ _Static_assert ((void *) (&stackframe->_pad + 1) == (void *)
&stackframe->ctx,
+ "trampoline expects no extra padding between "
+ "_pad and ctx");
+
+ if (_hurdsig_catch_memory_fault (stackframe))
+ {
+ /* We got a fault trying to write the stack frame.
+ We cannot set up the signal handler.
+ Returning NULL tells our caller, who will nuke us with a SIGILL. */
+ return NULL;
+ }
+ else
+ {
+ int ok;
+
+ extern void _hurdsig_longjmp_from_handler (void *, jmp_buf, int);
+
+ /* Add a link to the thread's active-resources list. We mark this as
+ the only user of the "resource", so the cleanup function will be
+ called by any longjmp which is unwinding past the signal frame.
+ The cleanup function (in sigunwind.c) will make sure that all the
+ appropriate cleanups done by sigreturn are taken care of. */
+ stackframe->link.cleanup = &_hurdsig_longjmp_from_handler;
+ stackframe->link.cleanup_data = &stackframe->ctx;
+ stackframe->link.resource.next = NULL;
+ stackframe->link.resource.prevp = NULL;
+ stackframe->link.thread.next = ss->active_resources;
+ stackframe->link.thread.prevp = &ss->active_resources;
+ if (stackframe->link.thread.next)
+ stackframe->link.thread.next->thread.prevp
+ = &stackframe->link.thread.next;
+ ss->active_resources = &stackframe->link;
+
+ /* Set up the sigcontext from the current state of the thread. */
+
+ scp = &stackframe->ctx;
+ scp->sc_onstack = ss->sigaltstack.ss_flags & SS_ONSTACK ? 1 : 0;
+
+ /* struct sigcontext is laid out so that starting at sc_x[0] mimics a
+ struct aarch64_thread_state. */
+ _Static_assert (offsetof (struct sigcontext, sc_aarch64_thread_state)
+ % __alignof__ (struct aarch64_thread_state) == 0,
+ "sc_aarch64_thread_state layout mismatch");
+ memcpy (&scp->sc_aarch64_thread_state,
+ &state->basic, sizeof (state->basic));
+
+ /* struct sigcontext is laid out so that starting at sc_v[0] mimics a
+ struct aarch64_float_state. */
+ _Static_assert (offsetof (struct sigcontext, sc_aarch64_float_state)
+ % __alignof__ (struct aarch64_float_state) == 0,
+ "sc_aarch64_float_state layout mismatch");
+ ok = machine_get_state (ss->thread, state, AARCH64_FLOAT_STATE,
+ &state->fpu, &scp->sc_aarch64_float_state,
+ sizeof (state->fpu));
+
+ /* Set up the arguments for the signal handler. */
+ stackframe->signo = signo;
+ if (action->sa_flags & SA_SIGINFO)
+ {
+ stackframe->posix.siginfop = &stackframe->siginfo;
+ stackframe->posix.uctxp = &stackframe->ucontext;
+ fill_siginfo (&stackframe->siginfo, signo, detail, state);
+ fill_ucontext (&stackframe->ucontext, scp);
+ }
+ else
+ {
+ if (detail->exc)
+ {
+ int nsigno;
+ _hurd_exception2signal_legacy (detail, &nsigno);
+ assert (nsigno == signo);
+ }
+ else
+ detail->code = 0;
+
+ stackframe->legacy.sigcode = detail->code;
+ stackframe->legacy.scp = &stackframe->ctx;
+ }
+
+ _hurdsig_end_catch_fault ();
+
+ if (!ok)
+ return NULL;
+ }
+
+ /* Modify the thread state to call the trampoline code on the new stack. */
+ state->basic.sp = (uintptr_t) sigsp;
+
+ if (rpc_wait)
+ {
+ /* The signalee thread was blocked in a mach_msg_trap system call,
+ still waiting for a reply. We will have it run the special
+ trampoline code which retries the message receive before running
+ the signal handler.
+
+ To do this we change the OPTION argument (in x1) to enable only
+ message reception, since the request message has already been
+ sent. */
+
+ assert (state->basic.x[1] & MACH_RCV_MSG);
+ /* Disable the message-send, since it has already completed. The
+ calls we retry need only wait to receive the reply message. */
+ state->basic.x[1] &= ~MACH_SEND_MSG;
+
+ /* Limit the time to receive the reply message, in case the server
+ claimed that `interrupt_operation' succeeded but in fact the RPC
+ is hung. */
+ state->basic.x[1] |= MACH_RCV_TIMEOUT;
+ state->basic.x[5] = _hurd_interrupted_rpc_timeout;
+
+ state->basic.pc = (uintptr_t) rpc_wait_trampoline;
+ /* After doing the message receive, the trampoline code will need to
+ update the x0 value to be restored by sigreturn. To simplify
+ the assembly code, we pass the address of its slot in SCP to the
+ trampoline code in x21. */
+ state->basic.x[21] = (uintptr_t) &scp->sc_x[0];
+ }
+ else
+ state->basic.pc = (uintptr_t) trampoline;
+
+ /* We pass the handler function to the trampoline code in x20. */
+ state->basic.x[20] = (uintptr_t) handler;
+
+ /* Clear pstate, notably reset BTYPE to 0. */
+ state->basic.cpsr = 0;
+
+ return scp;
+}
+
+asm ("rpc_wait_trampoline:\n"
+ /* This is the entry point when we have an RPC reply message to receive
+ before running the handler. The MACH_MSG_SEND bit has already been
+ cleared in the OPTION argument in our x1. For our convenience, x21
+ points to the sc_x[0] member of the sigcontext.
+
+ When the sigcontext was saved, x0 was MACH_RCV_INTERRUPTED. To repeat
+ the message call, we need to restore the original message buffer
+ pointer; intr-msg.h keeps a backup copy of it in x9 specifically for
+ this purpose. */
+ "mov x0, x9\n"
+ "svc #0\n"
+ /* Now the message receive has completed and the original caller of
+ the RPC (i.e. the code running when the signal arrived) needs to
+ see the final return value of the message receive in x0. So store
+ the new x0 value into the sc_x[0] member of the sigcontext (whose
+ address is in x21 to make this code simpler). */
+ "str x0, [x21]\n"
+
+ "trampoline:\n"
+ /* Entry point for running the handler normally. The arguments to the
+ handler function are on the top of the stack:
+
+ [sp] SIGNO
+ [sp, #8] SIGCODE
+ [sp, #16] SCP
+ [sp, #24] _pad
+
+ Pop them off to the registers, to pass as arguments to the handler.
+ */
+ "ldp x0, x1, [sp], #16\n"
+ "ldr x2, [sp], #16\n"
+ /* Call handler (signo, sigcode, scp). Note that this is an indirect
+ call not using x16/x17, so this requires the signal handler to start
+ with a proper "bti c" marker. */
+ "blr x20\n"
+ /* Call __sigreturn (), passing &CTX as SCP. CTX is on the top of
+ the stack. If __sigreturn () fails, we're in trouble. */
+ "mov x0, sp\n"
+ "bl __sigreturn\n"
+ "udf #0xdead");
--
2.44.0
- [PATCH v2 08/20] aarch64: Add dl-procinfo, (continued)
- [PATCH v2 08/20] aarch64: Add dl-procinfo, Sergey Bugaev, 2024/03/23
- [PATCH v2 11/20] mach: Add a basic AArch64 port, Sergey Bugaev, 2024/03/23
- [PATCH v2 13/20] hurd: Add a basic AArch64 port, Sergey Bugaev, 2024/03/23
- [PATCH v2 18/20] htl: Implement some support for TLS_DTV_AT_TP, Sergey Bugaev, 2024/03/23
- [PATCH v2 02/20] hurd: Stop relying on VM_MAX_ADDRESS, Sergey Bugaev, 2024/03/23
- [PATCH v2 03/20] Allow glibc to be compiled without EXEC_PAGESIZE, Sergey Bugaev, 2024/03/23
- [PATCH v2 07/20] aarch64: Move pointer_guard.h out of sysdeps/unix/sysv/linux, Sergey Bugaev, 2024/03/23
- [PATCH v2 10/20] aarch64: Allow building without kernel support for BTI, Sergey Bugaev, 2024/03/23
- [PATCH v2 12/20] mach: Declare the new thread_set_self_state () trap, Sergey Bugaev, 2024/03/23
- [PATCH v2 15/20] hurd: Implement longjmp for AArch64, Sergey Bugaev, 2024/03/23
- [PATCH v2 17/20] hurd: Add an AArch64 signal implementation,
Sergey Bugaev <=
- [PATCH v2 09/20] aarch64: Move saving user entry into _dl_start_user, Sergey Bugaev, 2024/03/23
- [PATCH v2 14/20] hurd: Implement TLS on AArch64, Sergey Bugaev, 2024/03/23
- [PATCH v2 16/20] Add FPE_FLTIDO, Sergey Bugaev, 2024/03/23
- [PATCH v2 19/20] htl: Add an AArch64 implementation, Sergey Bugaev, 2024/03/23
- [PATCH v2 20/20] hurd: Add expected aarch64-gnu abistlists, Sergey Bugaev, 2024/03/23
- Re: [PATCH v2 00/20] aarch64-gnu port & GNU/Hurd on AArch64 progress, Samuel Thibault, 2024/03/23