v4.19.13 snapshot.
diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c
new file mode 100644
index 0000000..5dcc942
--- /dev/null
+++ b/arch/arm64/kernel/signal.c
@@ -0,0 +1,981 @@
+/*
+ * Based on arch/arm/kernel/signal.c
+ *
+ * Copyright (C) 1995-2009 Russell King
+ * Copyright (C) 2012 ARM Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * 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 <linux/cache.h>
+#include <linux/compat.h>
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/signal.h>
+#include <linux/personality.h>
+#include <linux/freezer.h>
+#include <linux/stddef.h>
+#include <linux/uaccess.h>
+#include <linux/sizes.h>
+#include <linux/string.h>
+#include <linux/tracehook.h>
+#include <linux/ratelimit.h>
+#include <linux/syscalls.h>
+
+#include <asm/daifflags.h>
+#include <asm/debug-monitors.h>
+#include <asm/elf.h>
+#include <asm/cacheflush.h>
+#include <asm/ucontext.h>
+#include <asm/unistd.h>
+#include <asm/fpsimd.h>
+#include <asm/ptrace.h>
+#include <asm/signal32.h>
+#include <asm/traps.h>
+#include <asm/vdso.h>
+
+/*
+ * Do a signal return; undo the signal stack. These are aligned to 128-bit.
+ */
+struct rt_sigframe {
+ struct siginfo info;
+ struct ucontext uc;
+};
+
+struct frame_record {
+ u64 fp;
+ u64 lr;
+};
+
+struct rt_sigframe_user_layout {
+ struct rt_sigframe __user *sigframe;
+ struct frame_record __user *next_frame;
+
+ unsigned long size; /* size of allocated sigframe data */
+ unsigned long limit; /* largest allowed size */
+
+ unsigned long fpsimd_offset;
+ unsigned long esr_offset;
+ unsigned long sve_offset;
+ unsigned long extra_offset;
+ unsigned long end_offset;
+};
+
+#define BASE_SIGFRAME_SIZE round_up(sizeof(struct rt_sigframe), 16)
+#define TERMINATOR_SIZE round_up(sizeof(struct _aarch64_ctx), 16)
+#define EXTRA_CONTEXT_SIZE round_up(sizeof(struct extra_context), 16)
+
+static void init_user_layout(struct rt_sigframe_user_layout *user)
+{
+ const size_t reserved_size =
+ sizeof(user->sigframe->uc.uc_mcontext.__reserved);
+
+ memset(user, 0, sizeof(*user));
+ user->size = offsetof(struct rt_sigframe, uc.uc_mcontext.__reserved);
+
+ user->limit = user->size + reserved_size;
+
+ user->limit -= TERMINATOR_SIZE;
+ user->limit -= EXTRA_CONTEXT_SIZE;
+ /* Reserve space for extension and terminator ^ */
+}
+
+static size_t sigframe_size(struct rt_sigframe_user_layout const *user)
+{
+ return round_up(max(user->size, sizeof(struct rt_sigframe)), 16);
+}
+
+/*
+ * Sanity limit on the approximate maximum size of signal frame we'll
+ * try to generate. Stack alignment padding and the frame record are
+ * not taken into account. This limit is not a guarantee and is
+ * NOT ABI.
+ */
+#define SIGFRAME_MAXSZ SZ_64K
+
+static int __sigframe_alloc(struct rt_sigframe_user_layout *user,
+ unsigned long *offset, size_t size, bool extend)
+{
+ size_t padded_size = round_up(size, 16);
+
+ if (padded_size > user->limit - user->size &&
+ !user->extra_offset &&
+ extend) {
+ int ret;
+
+ user->limit += EXTRA_CONTEXT_SIZE;
+ ret = __sigframe_alloc(user, &user->extra_offset,
+ sizeof(struct extra_context), false);
+ if (ret) {
+ user->limit -= EXTRA_CONTEXT_SIZE;
+ return ret;
+ }
+
+ /* Reserve space for the __reserved[] terminator */
+ user->size += TERMINATOR_SIZE;
+
+ /*
+ * Allow expansion up to SIGFRAME_MAXSZ, ensuring space for
+ * the terminator:
+ */
+ user->limit = SIGFRAME_MAXSZ - TERMINATOR_SIZE;
+ }
+
+ /* Still not enough space? Bad luck! */
+ if (padded_size > user->limit - user->size)
+ return -ENOMEM;
+
+ *offset = user->size;
+ user->size += padded_size;
+
+ return 0;
+}
+
+/*
+ * Allocate space for an optional record of <size> bytes in the user
+ * signal frame. The offset from the signal frame base address to the
+ * allocated block is assigned to *offset.
+ */
+static int sigframe_alloc(struct rt_sigframe_user_layout *user,
+ unsigned long *offset, size_t size)
+{
+ return __sigframe_alloc(user, offset, size, true);
+}
+
+/* Allocate the null terminator record and prevent further allocations */
+static int sigframe_alloc_end(struct rt_sigframe_user_layout *user)
+{
+ int ret;
+
+ /* Un-reserve the space reserved for the terminator: */
+ user->limit += TERMINATOR_SIZE;
+
+ ret = sigframe_alloc(user, &user->end_offset,
+ sizeof(struct _aarch64_ctx));
+ if (ret)
+ return ret;
+
+ /* Prevent further allocation: */
+ user->limit = user->size;
+ return 0;
+}
+
+static void __user *apply_user_offset(
+ struct rt_sigframe_user_layout const *user, unsigned long offset)
+{
+ char __user *base = (char __user *)user->sigframe;
+
+ return base + offset;
+}
+
+static int preserve_fpsimd_context(struct fpsimd_context __user *ctx)
+{
+ struct user_fpsimd_state const *fpsimd =
+ ¤t->thread.uw.fpsimd_state;
+ int err;
+
+ /* copy the FP and status/control registers */
+ err = __copy_to_user(ctx->vregs, fpsimd->vregs, sizeof(fpsimd->vregs));
+ __put_user_error(fpsimd->fpsr, &ctx->fpsr, err);
+ __put_user_error(fpsimd->fpcr, &ctx->fpcr, err);
+
+ /* copy the magic/size information */
+ __put_user_error(FPSIMD_MAGIC, &ctx->head.magic, err);
+ __put_user_error(sizeof(struct fpsimd_context), &ctx->head.size, err);
+
+ return err ? -EFAULT : 0;
+}
+
+static int restore_fpsimd_context(struct fpsimd_context __user *ctx)
+{
+ struct user_fpsimd_state fpsimd;
+ __u32 magic, size;
+ int err = 0;
+
+ /* check the magic/size information */
+ __get_user_error(magic, &ctx->head.magic, err);
+ __get_user_error(size, &ctx->head.size, err);
+ if (err)
+ return -EFAULT;
+ if (magic != FPSIMD_MAGIC || size != sizeof(struct fpsimd_context))
+ return -EINVAL;
+
+ /* copy the FP and status/control registers */
+ err = __copy_from_user(fpsimd.vregs, ctx->vregs,
+ sizeof(fpsimd.vregs));
+ __get_user_error(fpsimd.fpsr, &ctx->fpsr, err);
+ __get_user_error(fpsimd.fpcr, &ctx->fpcr, err);
+
+ clear_thread_flag(TIF_SVE);
+
+ /* load the hardware registers from the fpsimd_state structure */
+ if (!err)
+ fpsimd_update_current_state(&fpsimd);
+
+ return err ? -EFAULT : 0;
+}
+
+
+struct user_ctxs {
+ struct fpsimd_context __user *fpsimd;
+ struct sve_context __user *sve;
+};
+
+#ifdef CONFIG_ARM64_SVE
+
+static int preserve_sve_context(struct sve_context __user *ctx)
+{
+ int err = 0;
+ u16 reserved[ARRAY_SIZE(ctx->__reserved)];
+ unsigned int vl = current->thread.sve_vl;
+ unsigned int vq = 0;
+
+ if (test_thread_flag(TIF_SVE))
+ vq = sve_vq_from_vl(vl);
+
+ memset(reserved, 0, sizeof(reserved));
+
+ __put_user_error(SVE_MAGIC, &ctx->head.magic, err);
+ __put_user_error(round_up(SVE_SIG_CONTEXT_SIZE(vq), 16),
+ &ctx->head.size, err);
+ __put_user_error(vl, &ctx->vl, err);
+ BUILD_BUG_ON(sizeof(ctx->__reserved) != sizeof(reserved));
+ err |= __copy_to_user(&ctx->__reserved, reserved, sizeof(reserved));
+
+ if (vq) {
+ /*
+ * This assumes that the SVE state has already been saved to
+ * the task struct by calling preserve_fpsimd_context().
+ */
+ err |= __copy_to_user((char __user *)ctx + SVE_SIG_REGS_OFFSET,
+ current->thread.sve_state,
+ SVE_SIG_REGS_SIZE(vq));
+ }
+
+ return err ? -EFAULT : 0;
+}
+
+static int restore_sve_fpsimd_context(struct user_ctxs *user)
+{
+ int err;
+ unsigned int vq;
+ struct user_fpsimd_state fpsimd;
+ struct sve_context sve;
+
+ if (__copy_from_user(&sve, user->sve, sizeof(sve)))
+ return -EFAULT;
+
+ if (sve.vl != current->thread.sve_vl)
+ return -EINVAL;
+
+ if (sve.head.size <= sizeof(*user->sve)) {
+ clear_thread_flag(TIF_SVE);
+ goto fpsimd_only;
+ }
+
+ vq = sve_vq_from_vl(sve.vl);
+
+ if (sve.head.size < SVE_SIG_CONTEXT_SIZE(vq))
+ return -EINVAL;
+
+ /*
+ * Careful: we are about __copy_from_user() directly into
+ * thread.sve_state with preemption enabled, so protection is
+ * needed to prevent a racing context switch from writing stale
+ * registers back over the new data.
+ */
+
+ fpsimd_flush_task_state(current);
+ barrier();
+ /* From now, fpsimd_thread_switch() won't clear TIF_FOREIGN_FPSTATE */
+
+ set_thread_flag(TIF_FOREIGN_FPSTATE);
+ barrier();
+ /* From now, fpsimd_thread_switch() won't touch thread.sve_state */
+
+ sve_alloc(current);
+ err = __copy_from_user(current->thread.sve_state,
+ (char __user const *)user->sve +
+ SVE_SIG_REGS_OFFSET,
+ SVE_SIG_REGS_SIZE(vq));
+ if (err)
+ return -EFAULT;
+
+ set_thread_flag(TIF_SVE);
+
+fpsimd_only:
+ /* copy the FP and status/control registers */
+ /* restore_sigframe() already checked that user->fpsimd != NULL. */
+ err = __copy_from_user(fpsimd.vregs, user->fpsimd->vregs,
+ sizeof(fpsimd.vregs));
+ __get_user_error(fpsimd.fpsr, &user->fpsimd->fpsr, err);
+ __get_user_error(fpsimd.fpcr, &user->fpsimd->fpcr, err);
+
+ /* load the hardware registers from the fpsimd_state structure */
+ if (!err)
+ fpsimd_update_current_state(&fpsimd);
+
+ return err ? -EFAULT : 0;
+}
+
+#else /* ! CONFIG_ARM64_SVE */
+
+/* Turn any non-optimised out attempts to use these into a link error: */
+extern int preserve_sve_context(void __user *ctx);
+extern int restore_sve_fpsimd_context(struct user_ctxs *user);
+
+#endif /* ! CONFIG_ARM64_SVE */
+
+
+static int parse_user_sigframe(struct user_ctxs *user,
+ struct rt_sigframe __user *sf)
+{
+ struct sigcontext __user *const sc = &sf->uc.uc_mcontext;
+ struct _aarch64_ctx __user *head;
+ char __user *base = (char __user *)&sc->__reserved;
+ size_t offset = 0;
+ size_t limit = sizeof(sc->__reserved);
+ bool have_extra_context = false;
+ char const __user *const sfp = (char const __user *)sf;
+
+ user->fpsimd = NULL;
+ user->sve = NULL;
+
+ if (!IS_ALIGNED((unsigned long)base, 16))
+ goto invalid;
+
+ while (1) {
+ int err = 0;
+ u32 magic, size;
+ char const __user *userp;
+ struct extra_context const __user *extra;
+ u64 extra_datap;
+ u32 extra_size;
+ struct _aarch64_ctx const __user *end;
+ u32 end_magic, end_size;
+
+ if (limit - offset < sizeof(*head))
+ goto invalid;
+
+ if (!IS_ALIGNED(offset, 16))
+ goto invalid;
+
+ head = (struct _aarch64_ctx __user *)(base + offset);
+ __get_user_error(magic, &head->magic, err);
+ __get_user_error(size, &head->size, err);
+ if (err)
+ return err;
+
+ if (limit - offset < size)
+ goto invalid;
+
+ switch (magic) {
+ case 0:
+ if (size)
+ goto invalid;
+
+ goto done;
+
+ case FPSIMD_MAGIC:
+ if (user->fpsimd)
+ goto invalid;
+
+ if (size < sizeof(*user->fpsimd))
+ goto invalid;
+
+ user->fpsimd = (struct fpsimd_context __user *)head;
+ break;
+
+ case ESR_MAGIC:
+ /* ignore */
+ break;
+
+ case SVE_MAGIC:
+ if (!system_supports_sve())
+ goto invalid;
+
+ if (user->sve)
+ goto invalid;
+
+ if (size < sizeof(*user->sve))
+ goto invalid;
+
+ user->sve = (struct sve_context __user *)head;
+ break;
+
+ case EXTRA_MAGIC:
+ if (have_extra_context)
+ goto invalid;
+
+ if (size < sizeof(*extra))
+ goto invalid;
+
+ userp = (char const __user *)head;
+
+ extra = (struct extra_context const __user *)userp;
+ userp += size;
+
+ __get_user_error(extra_datap, &extra->datap, err);
+ __get_user_error(extra_size, &extra->size, err);
+ if (err)
+ return err;
+
+ /* Check for the dummy terminator in __reserved[]: */
+
+ if (limit - offset - size < TERMINATOR_SIZE)
+ goto invalid;
+
+ end = (struct _aarch64_ctx const __user *)userp;
+ userp += TERMINATOR_SIZE;
+
+ __get_user_error(end_magic, &end->magic, err);
+ __get_user_error(end_size, &end->size, err);
+ if (err)
+ return err;
+
+ if (end_magic || end_size)
+ goto invalid;
+
+ /* Prevent looping/repeated parsing of extra_context */
+ have_extra_context = true;
+
+ base = (__force void __user *)extra_datap;
+ if (!IS_ALIGNED((unsigned long)base, 16))
+ goto invalid;
+
+ if (!IS_ALIGNED(extra_size, 16))
+ goto invalid;
+
+ if (base != userp)
+ goto invalid;
+
+ /* Reject "unreasonably large" frames: */
+ if (extra_size > sfp + SIGFRAME_MAXSZ - userp)
+ goto invalid;
+
+ /*
+ * Ignore trailing terminator in __reserved[]
+ * and start parsing extra data:
+ */
+ offset = 0;
+ limit = extra_size;
+
+ if (!access_ok(VERIFY_READ, base, limit))
+ goto invalid;
+
+ continue;
+
+ default:
+ goto invalid;
+ }
+
+ if (size < sizeof(*head))
+ goto invalid;
+
+ if (limit - offset < size)
+ goto invalid;
+
+ offset += size;
+ }
+
+done:
+ return 0;
+
+invalid:
+ return -EINVAL;
+}
+
+static int restore_sigframe(struct pt_regs *regs,
+ struct rt_sigframe __user *sf)
+{
+ sigset_t set;
+ int i, err;
+ struct user_ctxs user;
+
+ err = __copy_from_user(&set, &sf->uc.uc_sigmask, sizeof(set));
+ if (err == 0)
+ set_current_blocked(&set);
+
+ for (i = 0; i < 31; i++)
+ __get_user_error(regs->regs[i], &sf->uc.uc_mcontext.regs[i],
+ err);
+ __get_user_error(regs->sp, &sf->uc.uc_mcontext.sp, err);
+ __get_user_error(regs->pc, &sf->uc.uc_mcontext.pc, err);
+ __get_user_error(regs->pstate, &sf->uc.uc_mcontext.pstate, err);
+
+ /*
+ * Avoid sys_rt_sigreturn() restarting.
+ */
+ forget_syscall(regs);
+
+ err |= !valid_user_regs(®s->user_regs, current);
+ if (err == 0)
+ err = parse_user_sigframe(&user, sf);
+
+ if (err == 0) {
+ if (!user.fpsimd)
+ return -EINVAL;
+
+ if (user.sve) {
+ if (!system_supports_sve())
+ return -EINVAL;
+
+ err = restore_sve_fpsimd_context(&user);
+ } else {
+ err = restore_fpsimd_context(user.fpsimd);
+ }
+ }
+
+ return err;
+}
+
+SYSCALL_DEFINE0(rt_sigreturn)
+{
+ struct pt_regs *regs = current_pt_regs();
+ struct rt_sigframe __user *frame;
+
+ /* Always make any pending restarted system calls return -EINTR */
+ current->restart_block.fn = do_no_restart_syscall;
+
+ /*
+ * Since we stacked the signal on a 128-bit boundary, then 'sp' should
+ * be word aligned here.
+ */
+ if (regs->sp & 15)
+ goto badframe;
+
+ frame = (struct rt_sigframe __user *)regs->sp;
+
+ if (!access_ok(VERIFY_READ, frame, sizeof (*frame)))
+ goto badframe;
+
+ if (restore_sigframe(regs, frame))
+ goto badframe;
+
+ if (restore_altstack(&frame->uc.uc_stack))
+ goto badframe;
+
+ return regs->regs[0];
+
+badframe:
+ arm64_notify_segfault(regs->sp);
+ return 0;
+}
+
+/*
+ * Determine the layout of optional records in the signal frame
+ *
+ * add_all: if true, lays out the biggest possible signal frame for
+ * this task; otherwise, generates a layout for the current state
+ * of the task.
+ */
+static int setup_sigframe_layout(struct rt_sigframe_user_layout *user,
+ bool add_all)
+{
+ int err;
+
+ err = sigframe_alloc(user, &user->fpsimd_offset,
+ sizeof(struct fpsimd_context));
+ if (err)
+ return err;
+
+ /* fault information, if valid */
+ if (add_all || current->thread.fault_code) {
+ err = sigframe_alloc(user, &user->esr_offset,
+ sizeof(struct esr_context));
+ if (err)
+ return err;
+ }
+
+ if (system_supports_sve()) {
+ unsigned int vq = 0;
+
+ if (add_all || test_thread_flag(TIF_SVE)) {
+ int vl = sve_max_vl;
+
+ if (!add_all)
+ vl = current->thread.sve_vl;
+
+ vq = sve_vq_from_vl(vl);
+ }
+
+ err = sigframe_alloc(user, &user->sve_offset,
+ SVE_SIG_CONTEXT_SIZE(vq));
+ if (err)
+ return err;
+ }
+
+ return sigframe_alloc_end(user);
+}
+
+static int setup_sigframe(struct rt_sigframe_user_layout *user,
+ struct pt_regs *regs, sigset_t *set)
+{
+ int i, err = 0;
+ struct rt_sigframe __user *sf = user->sigframe;
+
+ /* set up the stack frame for unwinding */
+ __put_user_error(regs->regs[29], &user->next_frame->fp, err);
+ __put_user_error(regs->regs[30], &user->next_frame->lr, err);
+
+ for (i = 0; i < 31; i++)
+ __put_user_error(regs->regs[i], &sf->uc.uc_mcontext.regs[i],
+ err);
+ __put_user_error(regs->sp, &sf->uc.uc_mcontext.sp, err);
+ __put_user_error(regs->pc, &sf->uc.uc_mcontext.pc, err);
+ __put_user_error(regs->pstate, &sf->uc.uc_mcontext.pstate, err);
+
+ __put_user_error(current->thread.fault_address, &sf->uc.uc_mcontext.fault_address, err);
+
+ err |= __copy_to_user(&sf->uc.uc_sigmask, set, sizeof(*set));
+
+ if (err == 0) {
+ struct fpsimd_context __user *fpsimd_ctx =
+ apply_user_offset(user, user->fpsimd_offset);
+ err |= preserve_fpsimd_context(fpsimd_ctx);
+ }
+
+ /* fault information, if valid */
+ if (err == 0 && user->esr_offset) {
+ struct esr_context __user *esr_ctx =
+ apply_user_offset(user, user->esr_offset);
+
+ __put_user_error(ESR_MAGIC, &esr_ctx->head.magic, err);
+ __put_user_error(sizeof(*esr_ctx), &esr_ctx->head.size, err);
+ __put_user_error(current->thread.fault_code, &esr_ctx->esr, err);
+ }
+
+ /* Scalable Vector Extension state, if present */
+ if (system_supports_sve() && err == 0 && user->sve_offset) {
+ struct sve_context __user *sve_ctx =
+ apply_user_offset(user, user->sve_offset);
+ err |= preserve_sve_context(sve_ctx);
+ }
+
+ if (err == 0 && user->extra_offset) {
+ char __user *sfp = (char __user *)user->sigframe;
+ char __user *userp =
+ apply_user_offset(user, user->extra_offset);
+
+ struct extra_context __user *extra;
+ struct _aarch64_ctx __user *end;
+ u64 extra_datap;
+ u32 extra_size;
+
+ extra = (struct extra_context __user *)userp;
+ userp += EXTRA_CONTEXT_SIZE;
+
+ end = (struct _aarch64_ctx __user *)userp;
+ userp += TERMINATOR_SIZE;
+
+ /*
+ * extra_datap is just written to the signal frame.
+ * The value gets cast back to a void __user *
+ * during sigreturn.
+ */
+ extra_datap = (__force u64)userp;
+ extra_size = sfp + round_up(user->size, 16) - userp;
+
+ __put_user_error(EXTRA_MAGIC, &extra->head.magic, err);
+ __put_user_error(EXTRA_CONTEXT_SIZE, &extra->head.size, err);
+ __put_user_error(extra_datap, &extra->datap, err);
+ __put_user_error(extra_size, &extra->size, err);
+
+ /* Add the terminator */
+ __put_user_error(0, &end->magic, err);
+ __put_user_error(0, &end->size, err);
+ }
+
+ /* set the "end" magic */
+ if (err == 0) {
+ struct _aarch64_ctx __user *end =
+ apply_user_offset(user, user->end_offset);
+
+ __put_user_error(0, &end->magic, err);
+ __put_user_error(0, &end->size, err);
+ }
+
+ return err;
+}
+
+static int get_sigframe(struct rt_sigframe_user_layout *user,
+ struct ksignal *ksig, struct pt_regs *regs)
+{
+ unsigned long sp, sp_top;
+ int err;
+
+ init_user_layout(user);
+ err = setup_sigframe_layout(user, false);
+ if (err)
+ return err;
+
+ sp = sp_top = sigsp(regs->sp, ksig);
+
+ sp = round_down(sp - sizeof(struct frame_record), 16);
+ user->next_frame = (struct frame_record __user *)sp;
+
+ sp = round_down(sp, 16) - sigframe_size(user);
+ user->sigframe = (struct rt_sigframe __user *)sp;
+
+ /*
+ * Check that we can actually write to the signal frame.
+ */
+ if (!access_ok(VERIFY_WRITE, user->sigframe, sp_top - sp))
+ return -EFAULT;
+
+ return 0;
+}
+
+static void setup_return(struct pt_regs *regs, struct k_sigaction *ka,
+ struct rt_sigframe_user_layout *user, int usig)
+{
+ __sigrestore_t sigtramp;
+
+ regs->regs[0] = usig;
+ regs->sp = (unsigned long)user->sigframe;
+ regs->regs[29] = (unsigned long)&user->next_frame->fp;
+ regs->pc = (unsigned long)ka->sa.sa_handler;
+
+ if (ka->sa.sa_flags & SA_RESTORER)
+ sigtramp = ka->sa.sa_restorer;
+ else
+ sigtramp = VDSO_SYMBOL(current->mm->context.vdso, sigtramp);
+
+ regs->regs[30] = (unsigned long)sigtramp;
+}
+
+static int setup_rt_frame(int usig, struct ksignal *ksig, sigset_t *set,
+ struct pt_regs *regs)
+{
+ struct rt_sigframe_user_layout user;
+ struct rt_sigframe __user *frame;
+ int err = 0;
+
+ fpsimd_signal_preserve_current_state();
+
+ if (get_sigframe(&user, ksig, regs))
+ return 1;
+
+ frame = user.sigframe;
+
+ __put_user_error(0, &frame->uc.uc_flags, err);
+ __put_user_error(NULL, &frame->uc.uc_link, err);
+
+ err |= __save_altstack(&frame->uc.uc_stack, regs->sp);
+ err |= setup_sigframe(&user, regs, set);
+ if (err == 0) {
+ setup_return(regs, &ksig->ka, &user, usig);
+ if (ksig->ka.sa.sa_flags & SA_SIGINFO) {
+ err |= copy_siginfo_to_user(&frame->info, &ksig->info);
+ regs->regs[1] = (unsigned long)&frame->info;
+ regs->regs[2] = (unsigned long)&frame->uc;
+ }
+ }
+
+ return err;
+}
+
+static void setup_restart_syscall(struct pt_regs *regs)
+{
+ if (is_compat_task())
+ compat_setup_restart_syscall(regs);
+ else
+ regs->regs[8] = __NR_restart_syscall;
+}
+
+/*
+ * OK, we're invoking a handler
+ */
+static void handle_signal(struct ksignal *ksig, struct pt_regs *regs)
+{
+ struct task_struct *tsk = current;
+ sigset_t *oldset = sigmask_to_save();
+ int usig = ksig->sig;
+ int ret;
+
+ rseq_signal_deliver(ksig, regs);
+
+ /*
+ * Set up the stack frame
+ */
+ if (is_compat_task()) {
+ if (ksig->ka.sa.sa_flags & SA_SIGINFO)
+ ret = compat_setup_rt_frame(usig, ksig, oldset, regs);
+ else
+ ret = compat_setup_frame(usig, ksig, oldset, regs);
+ } else {
+ ret = setup_rt_frame(usig, ksig, oldset, regs);
+ }
+
+ /*
+ * Check that the resulting registers are actually sane.
+ */
+ ret |= !valid_user_regs(®s->user_regs, current);
+
+ /*
+ * Fast forward the stepping logic so we step into the signal
+ * handler.
+ */
+ if (!ret)
+ user_fastforward_single_step(tsk);
+
+ signal_setup_done(ret, ksig, 0);
+}
+
+/*
+ * Note that 'init' is a special process: it doesn't get signals it doesn't
+ * want to handle. Thus you cannot kill init even with a SIGKILL even by
+ * mistake.
+ *
+ * Note that we go through the signals twice: once to check the signals that
+ * the kernel can handle, and then we build all the user-level signal handling
+ * stack-frames in one go after that.
+ */
+static void do_signal(struct pt_regs *regs)
+{
+ unsigned long continue_addr = 0, restart_addr = 0;
+ int retval = 0;
+ struct ksignal ksig;
+ bool syscall = in_syscall(regs);
+
+ /*
+ * If we were from a system call, check for system call restarting...
+ */
+ if (syscall) {
+ continue_addr = regs->pc;
+ restart_addr = continue_addr - (compat_thumb_mode(regs) ? 2 : 4);
+ retval = regs->regs[0];
+
+ /*
+ * Avoid additional syscall restarting via ret_to_user.
+ */
+ forget_syscall(regs);
+
+ /*
+ * Prepare for system call restart. We do this here so that a
+ * debugger will see the already changed PC.
+ */
+ switch (retval) {
+ case -ERESTARTNOHAND:
+ case -ERESTARTSYS:
+ case -ERESTARTNOINTR:
+ case -ERESTART_RESTARTBLOCK:
+ regs->regs[0] = regs->orig_x0;
+ regs->pc = restart_addr;
+ break;
+ }
+ }
+
+ /*
+ * Get the signal to deliver. When running under ptrace, at this point
+ * the debugger may change all of our registers.
+ */
+ if (get_signal(&ksig)) {
+ /*
+ * Depending on the signal settings, we may need to revert the
+ * decision to restart the system call, but skip this if a
+ * debugger has chosen to restart at a different PC.
+ */
+ if (regs->pc == restart_addr &&
+ (retval == -ERESTARTNOHAND ||
+ retval == -ERESTART_RESTARTBLOCK ||
+ (retval == -ERESTARTSYS &&
+ !(ksig.ka.sa.sa_flags & SA_RESTART)))) {
+ regs->regs[0] = -EINTR;
+ regs->pc = continue_addr;
+ }
+
+ handle_signal(&ksig, regs);
+ return;
+ }
+
+ /*
+ * Handle restarting a different system call. As above, if a debugger
+ * has chosen to restart at a different PC, ignore the restart.
+ */
+ if (syscall && regs->pc == restart_addr) {
+ if (retval == -ERESTART_RESTARTBLOCK)
+ setup_restart_syscall(regs);
+ user_rewind_single_step(current);
+ }
+
+ restore_saved_sigmask();
+}
+
+asmlinkage void do_notify_resume(struct pt_regs *regs,
+ unsigned long thread_flags)
+{
+ /*
+ * The assembly code enters us with IRQs off, but it hasn't
+ * informed the tracing code of that for efficiency reasons.
+ * Update the trace code with the current status.
+ */
+ trace_hardirqs_off();
+
+ do {
+ /* Check valid user FS if needed */
+ addr_limit_user_check();
+
+ if (thread_flags & _TIF_NEED_RESCHED) {
+ /* Unmask Debug and SError for the next task */
+ local_daif_restore(DAIF_PROCCTX_NOIRQ);
+
+ schedule();
+ } else {
+ local_daif_restore(DAIF_PROCCTX);
+
+ if (thread_flags & _TIF_UPROBE)
+ uprobe_notify_resume(regs);
+
+ if (thread_flags & _TIF_SIGPENDING)
+ do_signal(regs);
+
+ if (thread_flags & _TIF_NOTIFY_RESUME) {
+ clear_thread_flag(TIF_NOTIFY_RESUME);
+ tracehook_notify_resume(regs);
+ rseq_handle_notify_resume(NULL, regs);
+ }
+
+ if (thread_flags & _TIF_FOREIGN_FPSTATE)
+ fpsimd_restore_current_state();
+ }
+
+ local_daif_mask();
+ thread_flags = READ_ONCE(current_thread_info()->flags);
+ } while (thread_flags & _TIF_WORK_MASK);
+}
+
+unsigned long __ro_after_init signal_minsigstksz;
+
+/*
+ * Determine the stack space required for guaranteed signal devliery.
+ * This function is used to populate AT_MINSIGSTKSZ at process startup.
+ * cpufeatures setup is assumed to be complete.
+ */
+void __init minsigstksz_setup(void)
+{
+ struct rt_sigframe_user_layout user;
+
+ init_user_layout(&user);
+
+ /*
+ * If this fails, SIGFRAME_MAXSZ needs to be enlarged. It won't
+ * be big enough, but it's our best guess:
+ */
+ if (WARN_ON(setup_sigframe_layout(&user, true)))
+ return;
+
+ signal_minsigstksz = sigframe_size(&user) +
+ round_up(sizeof(struct frame_record), 16) +
+ 16; /* max alignment padding */
+}