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-rw-r--r--arch/parisc/kernel/signal.c589
1 files changed, 589 insertions, 0 deletions
diff --git a/arch/parisc/kernel/signal.c b/arch/parisc/kernel/signal.c
new file mode 100644
index 000000000..8bc0ddaa6
--- /dev/null
+++ b/arch/parisc/kernel/signal.c
@@ -0,0 +1,589 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * PA-RISC architecture-specific signal handling support.
+ *
+ * Copyright (C) 2000 David Huggins-Daines <dhd@debian.org>
+ * Copyright (C) 2000 Linuxcare, Inc.
+ * Copyright (C) 2000-2022 Helge Deller <deller@gmx.de>
+ * Copyright (C) 2022 John David Anglin <dave.anglin@bell.net>
+ *
+ * Based on the ia64, i386, and alpha versions.
+ */
+
+#include <linux/sched.h>
+#include <linux/sched/debug.h>
+#include <linux/mm.h>
+#include <linux/smp.h>
+#include <linux/kernel.h>
+#include <linux/signal.h>
+#include <linux/errno.h>
+#include <linux/wait.h>
+#include <linux/ptrace.h>
+#include <linux/resume_user_mode.h>
+#include <linux/unistd.h>
+#include <linux/stddef.h>
+#include <linux/compat.h>
+#include <linux/elf.h>
+#include <asm/ucontext.h>
+#include <asm/rt_sigframe.h>
+#include <linux/uaccess.h>
+#include <asm/cacheflush.h>
+#include <asm/asm-offsets.h>
+#include <asm/vdso.h>
+
+#ifdef CONFIG_COMPAT
+#include "signal32.h"
+#endif
+
+#define DEBUG_SIG 0
+#define DEBUG_SIG_LEVEL 2
+
+#if DEBUG_SIG
+#define DBG(LEVEL, ...) \
+ ((DEBUG_SIG_LEVEL >= LEVEL) \
+ ? printk(__VA_ARGS__) : (void) 0)
+#else
+#define DBG(LEVEL, ...)
+#endif
+
+/* gcc will complain if a pointer is cast to an integer of different
+ * size. If you really need to do this (and we do for an ELF32 user
+ * application in an ELF64 kernel) then you have to do a cast to an
+ * integer of the same size first. The A() macro accomplishes
+ * this. */
+#define A(__x) ((unsigned long)(__x))
+
+/*
+ * Do a signal return - restore sigcontext.
+ */
+
+static long
+restore_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs)
+{
+ long err = 0;
+
+ err |= __copy_from_user(regs->gr, sc->sc_gr, sizeof(regs->gr));
+ err |= __copy_from_user(regs->fr, sc->sc_fr, sizeof(regs->fr));
+ err |= __copy_from_user(regs->iaoq, sc->sc_iaoq, sizeof(regs->iaoq));
+ err |= __copy_from_user(regs->iasq, sc->sc_iasq, sizeof(regs->iasq));
+ err |= __get_user(regs->sar, &sc->sc_sar);
+ DBG(2, "%s: iaoq is %#lx / %#lx\n",
+ __func__, regs->iaoq[0], regs->iaoq[1]);
+ DBG(2, "%s: r28 is %ld\n", __func__, regs->gr[28]);
+ return err;
+}
+
+void
+sys_rt_sigreturn(struct pt_regs *regs, int in_syscall)
+{
+ struct rt_sigframe __user *frame;
+ sigset_t set;
+ unsigned long usp = (regs->gr[30] & ~(0x01UL));
+ unsigned long sigframe_size = PARISC_RT_SIGFRAME_SIZE;
+#ifdef CONFIG_64BIT
+ struct compat_rt_sigframe __user * compat_frame;
+
+ if (is_compat_task())
+ sigframe_size = PARISC_RT_SIGFRAME_SIZE32;
+#endif
+
+ current->restart_block.fn = do_no_restart_syscall;
+
+ /* Unwind the user stack to get the rt_sigframe structure. */
+ frame = (struct rt_sigframe __user *)
+ (usp - sigframe_size);
+ DBG(2, "%s: frame is %p pid %d\n", __func__, frame, task_pid_nr(current));
+
+ regs->orig_r28 = 1; /* no restarts for sigreturn */
+
+#ifdef CONFIG_64BIT
+ compat_frame = (struct compat_rt_sigframe __user *)frame;
+
+ if (is_compat_task()) {
+ if (get_compat_sigset(&set, &compat_frame->uc.uc_sigmask))
+ goto give_sigsegv;
+ } else
+#endif
+ {
+ if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
+ goto give_sigsegv;
+ }
+
+ set_current_blocked(&set);
+
+ /* Good thing we saved the old gr[30], eh? */
+#ifdef CONFIG_64BIT
+ if (is_compat_task()) {
+ DBG(1, "%s: compat_frame->uc.uc_mcontext 0x%p\n",
+ __func__, &compat_frame->uc.uc_mcontext);
+// FIXME: Load upper half from register file
+ if (restore_sigcontext32(&compat_frame->uc.uc_mcontext,
+ &compat_frame->regs, regs))
+ goto give_sigsegv;
+ DBG(1, "%s: usp %#08lx stack 0x%p\n",
+ __func__, usp, &compat_frame->uc.uc_stack);
+ if (compat_restore_altstack(&compat_frame->uc.uc_stack))
+ goto give_sigsegv;
+ } else
+#endif
+ {
+ DBG(1, "%s: frame->uc.uc_mcontext 0x%p\n",
+ __func__, &frame->uc.uc_mcontext);
+ if (restore_sigcontext(&frame->uc.uc_mcontext, regs))
+ goto give_sigsegv;
+ DBG(1, "%s: usp %#08lx stack 0x%p\n",
+ __func__, usp, &frame->uc.uc_stack);
+ if (restore_altstack(&frame->uc.uc_stack))
+ goto give_sigsegv;
+ }
+
+
+
+ /* If we are on the syscall path IAOQ will not be restored, and
+ * if we are on the interrupt path we must not corrupt gr31.
+ */
+ if (in_syscall)
+ regs->gr[31] = regs->iaoq[0];
+
+ return;
+
+give_sigsegv:
+ DBG(1, "%s: Sending SIGSEGV\n", __func__);
+ force_sig(SIGSEGV);
+ return;
+}
+
+/*
+ * Set up a signal frame.
+ */
+
+static inline void __user *
+get_sigframe(struct k_sigaction *ka, unsigned long sp, size_t frame_size)
+{
+ /*FIXME: ELF32 vs. ELF64 has different frame_size, but since we
+ don't use the parameter it doesn't matter */
+
+ DBG(1, "%s: ka = %#lx, sp = %#lx, frame_size = %zu\n",
+ __func__, (unsigned long)ka, sp, frame_size);
+
+ /* Align alternate stack and reserve 64 bytes for the signal
+ handler's frame marker. */
+ if ((ka->sa.sa_flags & SA_ONSTACK) != 0 && ! sas_ss_flags(sp))
+ sp = (current->sas_ss_sp + 0x7f) & ~0x3f; /* Stacks grow up! */
+
+ DBG(1, "%s: Returning sp = %#lx\n", __func__, (unsigned long)sp);
+ return (void __user *) sp; /* Stacks grow up. Fun. */
+}
+
+static long
+setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs, int in_syscall)
+
+{
+ unsigned long flags = 0;
+ long err = 0;
+
+ if (on_sig_stack((unsigned long) sc))
+ flags |= PARISC_SC_FLAG_ONSTACK;
+ if (in_syscall) {
+ flags |= PARISC_SC_FLAG_IN_SYSCALL;
+ /* regs->iaoq is undefined in the syscall return path */
+ err |= __put_user(regs->gr[31], &sc->sc_iaoq[0]);
+ err |= __put_user(regs->gr[31]+4, &sc->sc_iaoq[1]);
+ err |= __put_user(regs->sr[3], &sc->sc_iasq[0]);
+ err |= __put_user(regs->sr[3], &sc->sc_iasq[1]);
+ DBG(1, "%s: iaoq %#lx / %#lx (in syscall)\n",
+ __func__, regs->gr[31], regs->gr[31]+4);
+ } else {
+ err |= __copy_to_user(sc->sc_iaoq, regs->iaoq, sizeof(regs->iaoq));
+ err |= __copy_to_user(sc->sc_iasq, regs->iasq, sizeof(regs->iasq));
+ DBG(1, "%s: iaoq %#lx / %#lx (not in syscall)\n",
+ __func__, regs->iaoq[0], regs->iaoq[1]);
+ }
+
+ err |= __put_user(flags, &sc->sc_flags);
+ err |= __copy_to_user(sc->sc_gr, regs->gr, sizeof(regs->gr));
+ err |= __copy_to_user(sc->sc_fr, regs->fr, sizeof(regs->fr));
+ err |= __put_user(regs->sar, &sc->sc_sar);
+ DBG(1, "%s: r28 is %ld\n", __func__, regs->gr[28]);
+
+ return err;
+}
+
+static long
+setup_rt_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs,
+ int in_syscall)
+{
+ struct rt_sigframe __user *frame;
+ unsigned long rp, usp;
+ unsigned long haddr, sigframe_size;
+ unsigned long start;
+ int err = 0;
+#ifdef CONFIG_64BIT
+ struct compat_rt_sigframe __user * compat_frame;
+#endif
+
+ usp = (regs->gr[30] & ~(0x01UL));
+ sigframe_size = PARISC_RT_SIGFRAME_SIZE;
+#ifdef CONFIG_64BIT
+ if (is_compat_task()) {
+ /* The gcc alloca implementation leaves garbage in the upper 32 bits of sp */
+ usp = (compat_uint_t)usp;
+ sigframe_size = PARISC_RT_SIGFRAME_SIZE32;
+ }
+#endif
+ frame = get_sigframe(&ksig->ka, usp, sigframe_size);
+
+ DBG(1, "%s: frame %p info %p\n", __func__, frame, &ksig->info);
+
+ start = (unsigned long) frame;
+ if (start >= TASK_SIZE_MAX - sigframe_size)
+ return -EFAULT;
+
+#ifdef CONFIG_64BIT
+
+ compat_frame = (struct compat_rt_sigframe __user *)frame;
+
+ if (is_compat_task()) {
+ DBG(1, "%s: frame->info = 0x%p\n", __func__, &compat_frame->info);
+ err |= copy_siginfo_to_user32(&compat_frame->info, &ksig->info);
+ err |= __compat_save_altstack( &compat_frame->uc.uc_stack, regs->gr[30]);
+ DBG(1, "%s: frame->uc = 0x%p\n", __func__, &compat_frame->uc);
+ DBG(1, "%s: frame->uc.uc_mcontext = 0x%p\n",
+ __func__, &compat_frame->uc.uc_mcontext);
+ err |= setup_sigcontext32(&compat_frame->uc.uc_mcontext,
+ &compat_frame->regs, regs, in_syscall);
+ err |= put_compat_sigset(&compat_frame->uc.uc_sigmask, set,
+ sizeof(compat_sigset_t));
+ } else
+#endif
+ {
+ DBG(1, "%s: frame->info = 0x%p\n", __func__, &frame->info);
+ err |= copy_siginfo_to_user(&frame->info, &ksig->info);
+ err |= __save_altstack(&frame->uc.uc_stack, regs->gr[30]);
+ DBG(1, "%s: frame->uc = 0x%p\n", __func__, &frame->uc);
+ DBG(1, "%s: frame->uc.uc_mcontext = 0x%p\n",
+ __func__, &frame->uc.uc_mcontext);
+ err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, in_syscall);
+ /* FIXME: Should probably be converted as well for the compat case */
+ err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
+ }
+
+ if (err)
+ return -EFAULT;
+
+#ifdef CONFIG_64BIT
+ if (!is_compat_task())
+ rp = VDSO64_SYMBOL(current, sigtramp_rt);
+ else
+#endif
+ rp = VDSO32_SYMBOL(current, sigtramp_rt);
+
+ if (in_syscall)
+ rp += 4*4; /* skip 4 instructions and start at ldi 1,%r25 */
+
+ haddr = A(ksig->ka.sa.sa_handler);
+ /* The sa_handler may be a pointer to a function descriptor */
+#ifdef CONFIG_64BIT
+ if (is_compat_task()) {
+#endif
+ if (haddr & PA_PLABEL_FDESC) {
+ Elf32_Fdesc fdesc;
+ Elf32_Fdesc __user *ufdesc = (Elf32_Fdesc __user *)A(haddr & ~3);
+
+ err = __copy_from_user(&fdesc, ufdesc, sizeof(fdesc));
+
+ if (err)
+ return -EFAULT;
+
+ haddr = fdesc.addr;
+ regs->gr[19] = fdesc.gp;
+ }
+#ifdef CONFIG_64BIT
+ } else {
+ Elf64_Fdesc fdesc;
+ Elf64_Fdesc __user *ufdesc = (Elf64_Fdesc __user *)A(haddr & ~3);
+
+ err = __copy_from_user(&fdesc, ufdesc, sizeof(fdesc));
+
+ if (err)
+ return -EFAULT;
+
+ haddr = fdesc.addr;
+ regs->gr[19] = fdesc.gp;
+ DBG(1, "%s: 64 bit signal, exe=%#lx, r19=%#lx, in_syscall=%d\n",
+ __func__, haddr, regs->gr[19], in_syscall);
+ }
+#endif
+
+ /* The syscall return path will create IAOQ values from r31.
+ */
+ if (in_syscall) {
+ regs->gr[31] = haddr;
+#ifdef CONFIG_64BIT
+ if (!test_thread_flag(TIF_32BIT))
+ sigframe_size |= 1; /* XXX ???? */
+#endif
+ } else {
+ unsigned long psw = USER_PSW;
+#ifdef CONFIG_64BIT
+ if (!test_thread_flag(TIF_32BIT))
+ psw |= PSW_W;
+#endif
+
+ /* If we are singlestepping, arrange a trap to be delivered
+ when we return to userspace. Note the semantics -- we
+ should trap before the first insn in the handler is
+ executed. Ref:
+ http://sources.redhat.com/ml/gdb/2004-11/msg00245.html
+ */
+ if (pa_psw(current)->r) {
+ pa_psw(current)->r = 0;
+ psw |= PSW_R;
+ mtctl(-1, 0);
+ }
+
+ regs->gr[0] = psw;
+ regs->iaoq[0] = haddr | PRIV_USER;
+ regs->iaoq[1] = regs->iaoq[0] + 4;
+ }
+
+ regs->gr[2] = rp; /* userland return pointer */
+ regs->gr[26] = ksig->sig; /* signal number */
+
+#ifdef CONFIG_64BIT
+ if (is_compat_task()) {
+ regs->gr[25] = A(&compat_frame->info); /* siginfo pointer */
+ regs->gr[24] = A(&compat_frame->uc); /* ucontext pointer */
+ } else
+#endif
+ {
+ regs->gr[25] = A(&frame->info); /* siginfo pointer */
+ regs->gr[24] = A(&frame->uc); /* ucontext pointer */
+ }
+
+ DBG(1, "%s: making sigreturn frame: %#lx + %#lx = %#lx\n", __func__,
+ regs->gr[30], sigframe_size,
+ regs->gr[30] + sigframe_size);
+ /* Raise the user stack pointer to make a proper call frame. */
+ regs->gr[30] = (A(frame) + sigframe_size);
+
+
+ DBG(1, "%s: sig deliver (%s,%d) frame=0x%p sp=%#lx iaoq=%#lx/%#lx rp=%#lx\n",
+ __func__, current->comm, current->pid, frame, regs->gr[30],
+ regs->iaoq[0], regs->iaoq[1], rp);
+
+ return 0;
+}
+
+/*
+ * OK, we're invoking a handler.
+ */
+
+static void
+handle_signal(struct ksignal *ksig, struct pt_regs *regs, int in_syscall)
+{
+ int ret;
+ sigset_t *oldset = sigmask_to_save();
+
+ DBG(1, "%s: sig=%d, ka=%p, info=%p, oldset=%p, regs=%p\n",
+ __func__, ksig->sig, &ksig->ka, &ksig->info, oldset, regs);
+
+ /* Set up the stack frame */
+ ret = setup_rt_frame(ksig, oldset, regs, in_syscall);
+
+ signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP) ||
+ test_thread_flag(TIF_BLOCKSTEP));
+
+ DBG(1, "%s: Exit (success), regs->gr[28] = %ld\n",
+ __func__, regs->gr[28]);
+}
+
+/*
+ * Check how the syscall number gets loaded into %r20 within
+ * the delay branch in userspace and adjust as needed.
+ */
+
+static void check_syscallno_in_delay_branch(struct pt_regs *regs)
+{
+ u32 opcode, source_reg;
+ u32 __user *uaddr;
+ int err;
+
+ /* Usually we don't have to restore %r20 (the system call number)
+ * because it gets loaded in the delay slot of the branch external
+ * instruction via the ldi instruction.
+ * In some cases a register-to-register copy instruction might have
+ * been used instead, in which case we need to copy the syscall
+ * number into the source register before returning to userspace.
+ */
+
+ /* A syscall is just a branch, so all we have to do is fiddle the
+ * return pointer so that the ble instruction gets executed again.
+ */
+ regs->gr[31] -= 8; /* delayed branching */
+
+ /* Get assembler opcode of code in delay branch */
+ uaddr = (unsigned int *) ((regs->gr[31] & ~3) + 4);
+ err = get_user(opcode, uaddr);
+ if (err)
+ return;
+
+ /* Check if delay branch uses "ldi int,%r20" */
+ if ((opcode & 0xffff0000) == 0x34140000)
+ return; /* everything ok, just return */
+
+ /* Check if delay branch uses "nop" */
+ if (opcode == INSN_NOP)
+ return;
+
+ /* Check if delay branch uses "copy %rX,%r20" */
+ if ((opcode & 0xffe0ffff) == 0x08000254) {
+ source_reg = (opcode >> 16) & 31;
+ regs->gr[source_reg] = regs->gr[20];
+ return;
+ }
+
+ pr_warn("syscall restart: %s (pid %d): unexpected opcode 0x%08x\n",
+ current->comm, task_pid_nr(current), opcode);
+}
+
+static inline void
+syscall_restart(struct pt_regs *regs, struct k_sigaction *ka)
+{
+ if (regs->orig_r28)
+ return;
+ regs->orig_r28 = 1; /* no more restarts */
+
+ DBG(1, "%s: orig_r28 = %ld pid %d r20 %ld\n",
+ __func__, regs->orig_r28, task_pid_nr(current), regs->gr[20]);
+
+ /* Check the return code */
+ switch (regs->gr[28]) {
+ case -ERESTART_RESTARTBLOCK:
+ case -ERESTARTNOHAND:
+ DBG(1, "%s: ERESTARTNOHAND: returning -EINTR\n", __func__);
+ regs->gr[28] = -EINTR;
+ break;
+ case -ERESTARTSYS:
+ if (!(ka->sa.sa_flags & SA_RESTART)) {
+ DBG(1, "%s: ERESTARTSYS: putting -EINTR pid %d\n",
+ __func__, task_pid_nr(current));
+ regs->gr[28] = -EINTR;
+ break;
+ }
+ fallthrough;
+ case -ERESTARTNOINTR:
+ DBG(1, "%s: %ld\n", __func__, regs->gr[28]);
+ check_syscallno_in_delay_branch(regs);
+ break;
+ }
+}
+
+static inline void
+insert_restart_trampoline(struct pt_regs *regs)
+{
+ if (regs->orig_r28)
+ return;
+ regs->orig_r28 = 1; /* no more restarts */
+
+ DBG(2, "%s: gr28 = %ld pid %d\n",
+ __func__, regs->gr[28], task_pid_nr(current));
+
+ switch (regs->gr[28]) {
+ case -ERESTART_RESTARTBLOCK: {
+ /* Restart the system call - no handlers present */
+ unsigned int *usp = (unsigned int *)regs->gr[30];
+ unsigned long rp;
+ long err = 0;
+
+ /* check that we don't exceed the stack */
+ if (A(&usp[0]) >= TASK_SIZE_MAX - 5 * sizeof(int))
+ return;
+
+ /* Call trampoline in vdso to restart the syscall
+ * with __NR_restart_syscall.
+ * Original return addresses are on stack like this:
+ *
+ * 0: <return address (orig r31)>
+ * 4: <2nd half for 64-bit>
+ */
+#ifdef CONFIG_64BIT
+ if (!is_compat_task()) {
+ err |= put_user(regs->gr[31] >> 32, &usp[0]);
+ err |= put_user(regs->gr[31] & 0xffffffff, &usp[1]);
+ rp = VDSO64_SYMBOL(current, restart_syscall);
+ } else
+#endif
+ {
+ err |= put_user(regs->gr[31], &usp[0]);
+ rp = VDSO32_SYMBOL(current, restart_syscall);
+ }
+ WARN_ON(err);
+
+ regs->gr[31] = rp;
+ DBG(1, "%s: ERESTART_RESTARTBLOCK\n", __func__);
+ return;
+ }
+ case -EINTR:
+ /* ok, was handled before and should be returned. */
+ break;
+ case -ERESTARTNOHAND:
+ case -ERESTARTSYS:
+ case -ERESTARTNOINTR:
+ DBG(1, "%s: Type %ld\n", __func__, regs->gr[28]);
+ check_syscallno_in_delay_branch(regs);
+ return;
+ default:
+ break;
+ }
+}
+
+/*
+ * We need to be able to restore the syscall arguments (r21-r26) to
+ * restart syscalls. Thus, the syscall path should save them in the
+ * pt_regs structure (it's okay to do so since they are caller-save
+ * registers). As noted below, the syscall number gets restored for
+ * us due to the magic of delayed branching.
+ */
+static void do_signal(struct pt_regs *regs, long in_syscall)
+{
+ struct ksignal ksig;
+ int restart_syscall;
+ bool has_handler;
+
+ has_handler = get_signal(&ksig);
+
+ restart_syscall = 0;
+ if (in_syscall)
+ restart_syscall = 1;
+
+ if (has_handler) {
+ /* Restart a system call if necessary. */
+ if (restart_syscall)
+ syscall_restart(regs, &ksig.ka);
+
+ handle_signal(&ksig, regs, in_syscall);
+ DBG(1, "%s: Handled signal pid %d\n",
+ __func__, task_pid_nr(current));
+ return;
+ }
+
+ /* Do we need to restart the system call? */
+ if (restart_syscall)
+ insert_restart_trampoline(regs);
+
+ DBG(1, "%s: Exit (not delivered), regs->gr[28] = %ld orig_r28 = %ld pid %d\n",
+ __func__, regs->gr[28], regs->orig_r28, task_pid_nr(current));
+
+ restore_saved_sigmask();
+}
+
+void do_notify_resume(struct pt_regs *regs, long in_syscall)
+{
+ if (test_thread_flag(TIF_SIGPENDING) ||
+ test_thread_flag(TIF_NOTIFY_SIGNAL))
+ do_signal(regs, in_syscall);
+
+ if (test_thread_flag(TIF_NOTIFY_RESUME))
+ resume_user_mode_work(regs);
+}
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