Update Linux to v5.10.109
Sourced from [1]
[1] https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.10.109.tar.xz
Change-Id: I19bca9fc6762d4e63bcf3e4cba88bbe560d9c76c
Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
diff --git a/arch/x86/entry/common.c b/arch/x86/entry/common.c
index 3f8e226..93a3122 100644
--- a/arch/x86/entry/common.c
+++ b/arch/x86/entry/common.c
@@ -10,281 +10,37 @@
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/sched/task_stack.h>
+#include <linux/entry-common.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/errno.h>
#include <linux/ptrace.h>
-#include <linux/tracehook.h>
-#include <linux/audit.h>
-#include <linux/seccomp.h>
-#include <linux/signal.h>
#include <linux/export.h>
-#include <linux/context_tracking.h>
-#include <linux/user-return-notifier.h>
#include <linux/nospec.h>
-#include <linux/uprobes.h>
-#include <linux/livepatch.h>
#include <linux/syscalls.h>
#include <linux/uaccess.h>
+#ifdef CONFIG_XEN_PV
+#include <xen/xen-ops.h>
+#include <xen/events.h>
+#endif
+
#include <asm/desc.h>
#include <asm/traps.h>
#include <asm/vdso.h>
#include <asm/cpufeature.h>
#include <asm/fpu/api.h>
#include <asm/nospec-branch.h>
-
-#define CREATE_TRACE_POINTS
-#include <trace/events/syscalls.h>
-
-#ifdef CONFIG_CONTEXT_TRACKING
-/* Called on entry from user mode with IRQs off. */
-__visible inline void enter_from_user_mode(void)
-{
- CT_WARN_ON(ct_state() != CONTEXT_USER);
- user_exit_irqoff();
-}
-#else
-static inline void enter_from_user_mode(void) {}
-#endif
-
-static void do_audit_syscall_entry(struct pt_regs *regs, u32 arch)
-{
-#ifdef CONFIG_X86_64
- if (arch == AUDIT_ARCH_X86_64) {
- audit_syscall_entry(regs->orig_ax, regs->di,
- regs->si, regs->dx, regs->r10);
- } else
-#endif
- {
- audit_syscall_entry(regs->orig_ax, regs->bx,
- regs->cx, regs->dx, regs->si);
- }
-}
-
-/*
- * Returns the syscall nr to run (which should match regs->orig_ax) or -1
- * to skip the syscall.
- */
-static long syscall_trace_enter(struct pt_regs *regs)
-{
- u32 arch = in_ia32_syscall() ? AUDIT_ARCH_I386 : AUDIT_ARCH_X86_64;
-
- struct thread_info *ti = current_thread_info();
- unsigned long ret = 0;
- u32 work;
-
- if (IS_ENABLED(CONFIG_DEBUG_ENTRY))
- BUG_ON(regs != task_pt_regs(current));
-
- work = READ_ONCE(ti->flags);
-
- if (work & (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_EMU)) {
- ret = tracehook_report_syscall_entry(regs);
- if (ret || (work & _TIF_SYSCALL_EMU))
- return -1L;
- }
-
-#ifdef CONFIG_SECCOMP
- /*
- * Do seccomp after ptrace, to catch any tracer changes.
- */
- if (work & _TIF_SECCOMP) {
- struct seccomp_data sd;
-
- sd.arch = arch;
- sd.nr = regs->orig_ax;
- sd.instruction_pointer = regs->ip;
-#ifdef CONFIG_X86_64
- if (arch == AUDIT_ARCH_X86_64) {
- sd.args[0] = regs->di;
- sd.args[1] = regs->si;
- sd.args[2] = regs->dx;
- sd.args[3] = regs->r10;
- sd.args[4] = regs->r8;
- sd.args[5] = regs->r9;
- } else
-#endif
- {
- sd.args[0] = regs->bx;
- sd.args[1] = regs->cx;
- sd.args[2] = regs->dx;
- sd.args[3] = regs->si;
- sd.args[4] = regs->di;
- sd.args[5] = regs->bp;
- }
-
- ret = __secure_computing(&sd);
- if (ret == -1)
- return ret;
- }
-#endif
-
- if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
- trace_sys_enter(regs, regs->orig_ax);
-
- do_audit_syscall_entry(regs, arch);
-
- return ret ?: regs->orig_ax;
-}
-
-#define EXIT_TO_USERMODE_LOOP_FLAGS \
- (_TIF_SIGPENDING | _TIF_NOTIFY_RESUME | _TIF_UPROBE | \
- _TIF_NEED_RESCHED | _TIF_USER_RETURN_NOTIFY | _TIF_PATCH_PENDING)
-
-static void exit_to_usermode_loop(struct pt_regs *regs, u32 cached_flags)
-{
- /*
- * In order to return to user mode, we need to have IRQs off with
- * none of EXIT_TO_USERMODE_LOOP_FLAGS set. Several of these flags
- * can be set at any time on preemptible kernels if we have IRQs on,
- * so we need to loop. Disabling preemption wouldn't help: doing the
- * work to clear some of the flags can sleep.
- */
- while (true) {
- /* We have work to do. */
- local_irq_enable();
-
- if (cached_flags & _TIF_NEED_RESCHED)
- schedule();
-
- if (cached_flags & _TIF_UPROBE)
- uprobe_notify_resume(regs);
-
- if (cached_flags & _TIF_PATCH_PENDING)
- klp_update_patch_state(current);
-
- /* deal with pending signal delivery */
- if (cached_flags & _TIF_SIGPENDING)
- do_signal(regs);
-
- if (cached_flags & _TIF_NOTIFY_RESUME) {
- clear_thread_flag(TIF_NOTIFY_RESUME);
- tracehook_notify_resume(regs);
- rseq_handle_notify_resume(NULL, regs);
- }
-
- if (cached_flags & _TIF_USER_RETURN_NOTIFY)
- fire_user_return_notifiers();
-
- /* Disable IRQs and retry */
- local_irq_disable();
-
- cached_flags = READ_ONCE(current_thread_info()->flags);
-
- if (!(cached_flags & EXIT_TO_USERMODE_LOOP_FLAGS))
- break;
- }
-}
-
-/* Called with IRQs disabled. */
-__visible inline void prepare_exit_to_usermode(struct pt_regs *regs)
-{
- struct thread_info *ti = current_thread_info();
- u32 cached_flags;
-
- addr_limit_user_check();
-
- lockdep_assert_irqs_disabled();
- lockdep_sys_exit();
-
- cached_flags = READ_ONCE(ti->flags);
-
- if (unlikely(cached_flags & EXIT_TO_USERMODE_LOOP_FLAGS))
- exit_to_usermode_loop(regs, cached_flags);
-
- /* Reload ti->flags; we may have rescheduled above. */
- cached_flags = READ_ONCE(ti->flags);
-
- fpregs_assert_state_consistent();
- if (unlikely(cached_flags & _TIF_NEED_FPU_LOAD))
- switch_fpu_return();
-
-#ifdef CONFIG_COMPAT
- /*
- * Compat syscalls set TS_COMPAT. Make sure we clear it before
- * returning to user mode. We need to clear it *after* signal
- * handling, because syscall restart has a fixup for compat
- * syscalls. The fixup is exercised by the ptrace_syscall_32
- * selftest.
- *
- * We also need to clear TS_REGS_POKED_I386: the 32-bit tracer
- * special case only applies after poking regs and before the
- * very next return to user mode.
- */
- ti->status &= ~(TS_COMPAT|TS_I386_REGS_POKED);
-#endif
-
- user_enter_irqoff();
-
- mds_user_clear_cpu_buffers();
-}
-
-#define SYSCALL_EXIT_WORK_FLAGS \
- (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | \
- _TIF_SINGLESTEP | _TIF_SYSCALL_TRACEPOINT)
-
-static void syscall_slow_exit_work(struct pt_regs *regs, u32 cached_flags)
-{
- bool step;
-
- audit_syscall_exit(regs);
-
- if (cached_flags & _TIF_SYSCALL_TRACEPOINT)
- trace_sys_exit(regs, regs->ax);
-
- /*
- * If TIF_SYSCALL_EMU is set, we only get here because of
- * TIF_SINGLESTEP (i.e. this is PTRACE_SYSEMU_SINGLESTEP).
- * We already reported this syscall instruction in
- * syscall_trace_enter().
- */
- step = unlikely(
- (cached_flags & (_TIF_SINGLESTEP | _TIF_SYSCALL_EMU))
- == _TIF_SINGLESTEP);
- if (step || cached_flags & _TIF_SYSCALL_TRACE)
- tracehook_report_syscall_exit(regs, step);
-}
-
-/*
- * Called with IRQs on and fully valid regs. Returns with IRQs off in a
- * state such that we can immediately switch to user mode.
- */
-__visible inline void syscall_return_slowpath(struct pt_regs *regs)
-{
- struct thread_info *ti = current_thread_info();
- u32 cached_flags = READ_ONCE(ti->flags);
-
- CT_WARN_ON(ct_state() != CONTEXT_KERNEL);
-
- if (IS_ENABLED(CONFIG_PROVE_LOCKING) &&
- WARN(irqs_disabled(), "syscall %ld left IRQs disabled", regs->orig_ax))
- local_irq_enable();
-
- rseq_syscall(regs);
-
- /*
- * First do one-time work. If these work items are enabled, we
- * want to run them exactly once per syscall exit with IRQs on.
- */
- if (unlikely(cached_flags & SYSCALL_EXIT_WORK_FLAGS))
- syscall_slow_exit_work(regs, cached_flags);
-
- local_irq_disable();
- prepare_exit_to_usermode(regs);
-}
+#include <asm/io_bitmap.h>
+#include <asm/syscall.h>
+#include <asm/irq_stack.h>
#ifdef CONFIG_X86_64
-__visible void do_syscall_64(unsigned long nr, struct pt_regs *regs)
+__visible noinstr void do_syscall_64(unsigned long nr, struct pt_regs *regs)
{
- struct thread_info *ti;
+ nr = syscall_enter_from_user_mode(regs, nr);
- enter_from_user_mode();
- local_irq_enable();
- ti = current_thread_info();
- if (READ_ONCE(ti->flags) & _TIF_WORK_SYSCALL_ENTRY)
- nr = syscall_trace_enter(regs);
-
+ instrumentation_begin();
if (likely(nr < NR_syscalls)) {
nr = array_index_nospec(nr, NR_syscalls);
regs->ax = sys_call_table[nr](regs);
@@ -296,76 +52,107 @@
regs->ax = x32_sys_call_table[nr](regs);
#endif
}
-
- syscall_return_slowpath(regs);
+ instrumentation_end();
+ syscall_exit_to_user_mode(regs);
}
#endif
#if defined(CONFIG_X86_32) || defined(CONFIG_IA32_EMULATION)
-/*
- * Does a 32-bit syscall. Called with IRQs on in CONTEXT_KERNEL. Does
- * all entry and exit work and returns with IRQs off. This function is
- * extremely hot in workloads that use it, and it's usually called from
- * do_fast_syscall_32, so forcibly inline it to improve performance.
- */
-static __always_inline void do_syscall_32_irqs_on(struct pt_regs *regs)
+static __always_inline unsigned int syscall_32_enter(struct pt_regs *regs)
{
- struct thread_info *ti = current_thread_info();
- unsigned int nr = (unsigned int)regs->orig_ax;
+ if (IS_ENABLED(CONFIG_IA32_EMULATION))
+ current_thread_info()->status |= TS_COMPAT;
-#ifdef CONFIG_IA32_EMULATION
- ti->status |= TS_COMPAT;
-#endif
+ return (unsigned int)regs->orig_ax;
+}
- if (READ_ONCE(ti->flags) & _TIF_WORK_SYSCALL_ENTRY) {
- /*
- * Subtlety here: if ptrace pokes something larger than
- * 2^32-1 into orig_ax, this truncates it. This may or
- * may not be necessary, but it matches the old asm
- * behavior.
- */
- nr = syscall_trace_enter(regs);
- }
-
+/*
+ * Invoke a 32-bit syscall. Called with IRQs on in CONTEXT_KERNEL.
+ */
+static __always_inline void do_syscall_32_irqs_on(struct pt_regs *regs,
+ unsigned int nr)
+{
if (likely(nr < IA32_NR_syscalls)) {
nr = array_index_nospec(nr, IA32_NR_syscalls);
-#ifdef CONFIG_IA32_EMULATION
regs->ax = ia32_sys_call_table[nr](regs);
-#else
- /*
- * It's possible that a 32-bit syscall implementation
- * takes a 64-bit parameter but nonetheless assumes that
- * the high bits are zero. Make sure we zero-extend all
- * of the args.
- */
- regs->ax = ia32_sys_call_table[nr](
- (unsigned int)regs->bx, (unsigned int)regs->cx,
- (unsigned int)regs->dx, (unsigned int)regs->si,
- (unsigned int)regs->di, (unsigned int)regs->bp);
-#endif /* CONFIG_IA32_EMULATION */
}
-
- syscall_return_slowpath(regs);
}
/* Handles int $0x80 */
-__visible void do_int80_syscall_32(struct pt_regs *regs)
+__visible noinstr void do_int80_syscall_32(struct pt_regs *regs)
{
- enter_from_user_mode();
- local_irq_enable();
- do_syscall_32_irqs_on(regs);
+ unsigned int nr = syscall_32_enter(regs);
+
+ /*
+ * Subtlety here: if ptrace pokes something larger than 2^32-1 into
+ * orig_ax, the unsigned int return value truncates it. This may
+ * or may not be necessary, but it matches the old asm behavior.
+ */
+ nr = (unsigned int)syscall_enter_from_user_mode(regs, nr);
+ instrumentation_begin();
+
+ do_syscall_32_irqs_on(regs, nr);
+
+ instrumentation_end();
+ syscall_exit_to_user_mode(regs);
+}
+
+static noinstr bool __do_fast_syscall_32(struct pt_regs *regs)
+{
+ unsigned int nr = syscall_32_enter(regs);
+ int res;
+
+ /*
+ * This cannot use syscall_enter_from_user_mode() as it has to
+ * fetch EBP before invoking any of the syscall entry work
+ * functions.
+ */
+ syscall_enter_from_user_mode_prepare(regs);
+
+ instrumentation_begin();
+ /* Fetch EBP from where the vDSO stashed it. */
+ if (IS_ENABLED(CONFIG_X86_64)) {
+ /*
+ * Micro-optimization: the pointer we're following is
+ * explicitly 32 bits, so it can't be out of range.
+ */
+ res = __get_user(*(u32 *)®s->bp,
+ (u32 __user __force *)(unsigned long)(u32)regs->sp);
+ } else {
+ res = get_user(*(u32 *)®s->bp,
+ (u32 __user __force *)(unsigned long)(u32)regs->sp);
+ }
+
+ if (res) {
+ /* User code screwed up. */
+ regs->ax = -EFAULT;
+
+ local_irq_disable();
+ instrumentation_end();
+ irqentry_exit_to_user_mode(regs);
+ return false;
+ }
+
+ /* The case truncates any ptrace induced syscall nr > 2^32 -1 */
+ nr = (unsigned int)syscall_enter_from_user_mode_work(regs, nr);
+
+ /* Now this is just like a normal syscall. */
+ do_syscall_32_irqs_on(regs, nr);
+
+ instrumentation_end();
+ syscall_exit_to_user_mode(regs);
+ return true;
}
/* Returns 0 to return using IRET or 1 to return using SYSEXIT/SYSRETL. */
-__visible long do_fast_syscall_32(struct pt_regs *regs)
+__visible noinstr long do_fast_syscall_32(struct pt_regs *regs)
{
/*
* Called using the internal vDSO SYSENTER/SYSCALL32 calling
* convention. Adjust regs so it looks like we entered using int80.
*/
-
unsigned long landing_pad = (unsigned long)current->mm->context.vdso +
- vdso_image_32.sym_int80_landing_pad;
+ vdso_image_32.sym_int80_landing_pad;
/*
* SYSENTER loses EIP, and even SYSCALL32 needs us to skip forward
@@ -374,34 +161,9 @@
*/
regs->ip = landing_pad;
- enter_from_user_mode();
-
- local_irq_enable();
-
- /* Fetch EBP from where the vDSO stashed it. */
- if (
-#ifdef CONFIG_X86_64
- /*
- * Micro-optimization: the pointer we're following is explicitly
- * 32 bits, so it can't be out of range.
- */
- __get_user(*(u32 *)®s->bp,
- (u32 __user __force *)(unsigned long)(u32)regs->sp)
-#else
- get_user(*(u32 *)®s->bp,
- (u32 __user __force *)(unsigned long)(u32)regs->sp)
-#endif
- ) {
-
- /* User code screwed up. */
- local_irq_disable();
- regs->ax = -EFAULT;
- prepare_exit_to_usermode(regs);
- return 0; /* Keep it simple: use IRET. */
- }
-
- /* Now this is just like a normal syscall. */
- do_syscall_32_irqs_on(regs);
+ /* Invoke the syscall. If it failed, keep it simple: use IRET. */
+ if (!__do_fast_syscall_32(regs))
+ return 0;
#ifdef CONFIG_X86_64
/*
@@ -433,4 +195,94 @@
(regs->flags & (X86_EFLAGS_RF | X86_EFLAGS_TF | X86_EFLAGS_VM)) == 0;
#endif
}
+
+/* Returns 0 to return using IRET or 1 to return using SYSEXIT/SYSRETL. */
+__visible noinstr long do_SYSENTER_32(struct pt_regs *regs)
+{
+ /* SYSENTER loses RSP, but the vDSO saved it in RBP. */
+ regs->sp = regs->bp;
+
+ /* SYSENTER clobbers EFLAGS.IF. Assume it was set in usermode. */
+ regs->flags |= X86_EFLAGS_IF;
+
+ return do_fast_syscall_32(regs);
+}
#endif
+
+SYSCALL_DEFINE0(ni_syscall)
+{
+ return -ENOSYS;
+}
+
+#ifdef CONFIG_XEN_PV
+#ifndef CONFIG_PREEMPTION
+/*
+ * Some hypercalls issued by the toolstack can take many 10s of
+ * seconds. Allow tasks running hypercalls via the privcmd driver to
+ * be voluntarily preempted even if full kernel preemption is
+ * disabled.
+ *
+ * Such preemptible hypercalls are bracketed by
+ * xen_preemptible_hcall_begin() and xen_preemptible_hcall_end()
+ * calls.
+ */
+DEFINE_PER_CPU(bool, xen_in_preemptible_hcall);
+EXPORT_SYMBOL_GPL(xen_in_preemptible_hcall);
+
+/*
+ * In case of scheduling the flag must be cleared and restored after
+ * returning from schedule as the task might move to a different CPU.
+ */
+static __always_inline bool get_and_clear_inhcall(void)
+{
+ bool inhcall = __this_cpu_read(xen_in_preemptible_hcall);
+
+ __this_cpu_write(xen_in_preemptible_hcall, false);
+ return inhcall;
+}
+
+static __always_inline void restore_inhcall(bool inhcall)
+{
+ __this_cpu_write(xen_in_preemptible_hcall, inhcall);
+}
+#else
+static __always_inline bool get_and_clear_inhcall(void) { return false; }
+static __always_inline void restore_inhcall(bool inhcall) { }
+#endif
+
+static void __xen_pv_evtchn_do_upcall(void)
+{
+ irq_enter_rcu();
+ inc_irq_stat(irq_hv_callback_count);
+
+ xen_hvm_evtchn_do_upcall();
+
+ irq_exit_rcu();
+}
+
+__visible noinstr void xen_pv_evtchn_do_upcall(struct pt_regs *regs)
+{
+ struct pt_regs *old_regs;
+ bool inhcall;
+ irqentry_state_t state;
+
+ state = irqentry_enter(regs);
+ old_regs = set_irq_regs(regs);
+
+ instrumentation_begin();
+ run_on_irqstack_cond(__xen_pv_evtchn_do_upcall, regs);
+ instrumentation_end();
+
+ set_irq_regs(old_regs);
+
+ inhcall = get_and_clear_inhcall();
+ if (inhcall && !WARN_ON_ONCE(state.exit_rcu)) {
+ instrumentation_begin();
+ irqentry_exit_cond_resched();
+ instrumentation_end();
+ restore_inhcall(inhcall);
+ } else {
+ irqentry_exit(regs, state);
+ }
+}
+#endif /* CONFIG_XEN_PV */