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-rw-r--r--arch/arm64/include/asm/sdei.h47
-rw-r--r--arch/arm64/include/asm/stacktrace.h3
-rw-r--r--arch/arm64/kernel/Makefile1
-rw-r--r--arch/arm64/kernel/asm-offsets.c5
-rw-r--r--arch/arm64/kernel/entry.S101
-rw-r--r--arch/arm64/kernel/sdei.c219
-rw-r--r--arch/arm64/kernel/smp.c11
7 files changed, 384 insertions, 3 deletions
diff --git a/arch/arm64/include/asm/sdei.h b/arch/arm64/include/asm/sdei.h
index 59f26b6e673d..d58a31ab525a 100644
--- a/arch/arm64/include/asm/sdei.h
+++ b/arch/arm64/include/asm/sdei.h
@@ -3,6 +3,49 @@
#ifndef __ASM_SDEI_H
#define __ASM_SDEI_H
-/* Later patches add the arch specific bits */
+/* Values for sdei_exit_mode */
+#define SDEI_EXIT_HVC 0
+#define SDEI_EXIT_SMC 1
-#endif /* __ASM_SDEI_H */
+#define SDEI_STACK_SIZE IRQ_STACK_SIZE
+
+#ifndef __ASSEMBLY__
+
+#include <linux/linkage.h>
+#include <linux/preempt.h>
+#include <linux/types.h>
+
+#include <asm/virt.h>
+
+extern unsigned long sdei_exit_mode;
+
+/* Software Delegated Exception entry point from firmware*/
+asmlinkage void __sdei_asm_handler(unsigned long event_num, unsigned long arg,
+ unsigned long pc, unsigned long pstate);
+
+/*
+ * The above entry point does the minimum to call C code. This function does
+ * anything else, before calling the driver.
+ */
+struct sdei_registered_event;
+asmlinkage unsigned long __sdei_handler(struct pt_regs *regs,
+ struct sdei_registered_event *arg);
+
+unsigned long sdei_arch_get_entry_point(int conduit);
+#define sdei_arch_get_entry_point(x) sdei_arch_get_entry_point(x)
+
+bool _on_sdei_stack(unsigned long sp);
+static inline bool on_sdei_stack(unsigned long sp)
+{
+ if (!IS_ENABLED(CONFIG_VMAP_STACK))
+ return false;
+ if (!IS_ENABLED(CONFIG_ARM_SDE_INTERFACE))
+ return false;
+ if (in_nmi())
+ return _on_sdei_stack(sp);
+
+ return false;
+}
+
+#endif /* __ASSEMBLY__ */
+#endif /* __ASM_SDEI_H */
diff --git a/arch/arm64/include/asm/stacktrace.h b/arch/arm64/include/asm/stacktrace.h
index 6ad30776e984..472ef944e932 100644
--- a/arch/arm64/include/asm/stacktrace.h
+++ b/arch/arm64/include/asm/stacktrace.h
@@ -22,6 +22,7 @@
#include <asm/memory.h>
#include <asm/ptrace.h>
+#include <asm/sdei.h>
struct stackframe {
unsigned long fp;
@@ -85,6 +86,8 @@ static inline bool on_accessible_stack(struct task_struct *tsk, unsigned long sp
return true;
if (on_overflow_stack(sp))
return true;
+ if (on_sdei_stack(sp))
+ return true;
return false;
}
diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
index 0c760db04858..b87541360f43 100644
--- a/arch/arm64/kernel/Makefile
+++ b/arch/arm64/kernel/Makefile
@@ -52,6 +52,7 @@ arm64-obj-$(CONFIG_KEXEC) += machine_kexec.o relocate_kernel.o \
arm64-obj-$(CONFIG_ARM64_RELOC_TEST) += arm64-reloc-test.o
arm64-reloc-test-y := reloc_test_core.o reloc_test_syms.o
arm64-obj-$(CONFIG_CRASH_DUMP) += crash_dump.o
+arm64-obj-$(CONFIG_ARM_SDE_INTERFACE) += sdei.o
ifeq ($(CONFIG_KVM),y)
arm64-obj-$(CONFIG_HARDEN_BRANCH_PREDICTOR) += bpi.o
diff --git a/arch/arm64/kernel/asm-offsets.c b/arch/arm64/kernel/asm-offsets.c
index af247d10252f..1dcc493f5765 100644
--- a/arch/arm64/kernel/asm-offsets.c
+++ b/arch/arm64/kernel/asm-offsets.c
@@ -18,6 +18,7 @@
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
+#include <linux/arm_sdei.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/dma-mapping.h>
@@ -158,5 +159,9 @@ int main(void)
#ifdef CONFIG_UNMAP_KERNEL_AT_EL0
DEFINE(TRAMP_VALIAS, TRAMP_VALIAS);
#endif
+#ifdef CONFIG_ARM_SDE_INTERFACE
+ DEFINE(SDEI_EVENT_INTREGS, offsetof(struct sdei_registered_event, interrupted_regs));
+ DEFINE(SDEI_EVENT_PRIORITY, offsetof(struct sdei_registered_event, priority));
+#endif
return 0;
}
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index 07a7d4db8ec4..40bf5083d182 100644
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -1153,3 +1153,104 @@ ENTRY(ret_from_fork)
b ret_to_user
ENDPROC(ret_from_fork)
NOKPROBE(ret_from_fork)
+
+#ifdef CONFIG_ARM_SDE_INTERFACE
+
+#include <asm/sdei.h>
+#include <uapi/linux/arm_sdei.h>
+
+/*
+ * Software Delegated Exception entry point.
+ *
+ * x0: Event number
+ * x1: struct sdei_registered_event argument from registration time.
+ * x2: interrupted PC
+ * x3: interrupted PSTATE
+ *
+ * Firmware has preserved x0->x17 for us, we must save/restore the rest to
+ * follow SMC-CC. We save (or retrieve) all the registers as the handler may
+ * want them.
+ */
+ENTRY(__sdei_asm_handler)
+ stp x2, x3, [x1, #SDEI_EVENT_INTREGS + S_PC]
+ stp x4, x5, [x1, #SDEI_EVENT_INTREGS + 16 * 2]
+ stp x6, x7, [x1, #SDEI_EVENT_INTREGS + 16 * 3]
+ stp x8, x9, [x1, #SDEI_EVENT_INTREGS + 16 * 4]
+ stp x10, x11, [x1, #SDEI_EVENT_INTREGS + 16 * 5]
+ stp x12, x13, [x1, #SDEI_EVENT_INTREGS + 16 * 6]
+ stp x14, x15, [x1, #SDEI_EVENT_INTREGS + 16 * 7]
+ stp x16, x17, [x1, #SDEI_EVENT_INTREGS + 16 * 8]
+ stp x18, x19, [x1, #SDEI_EVENT_INTREGS + 16 * 9]
+ stp x20, x21, [x1, #SDEI_EVENT_INTREGS + 16 * 10]
+ stp x22, x23, [x1, #SDEI_EVENT_INTREGS + 16 * 11]
+ stp x24, x25, [x1, #SDEI_EVENT_INTREGS + 16 * 12]
+ stp x26, x27, [x1, #SDEI_EVENT_INTREGS + 16 * 13]
+ stp x28, x29, [x1, #SDEI_EVENT_INTREGS + 16 * 14]
+ mov x4, sp
+ stp lr, x4, [x1, #SDEI_EVENT_INTREGS + S_LR]
+
+ mov x19, x1
+
+#ifdef CONFIG_VMAP_STACK
+ /*
+ * entry.S may have been using sp as a scratch register, find whether
+ * this is a normal or critical event and switch to the appropriate
+ * stack for this CPU.
+ */
+ ldrb w4, [x19, #SDEI_EVENT_PRIORITY]
+ cbnz w4, 1f
+ ldr_this_cpu dst=x5, sym=sdei_stack_normal_ptr, tmp=x6
+ b 2f
+1: ldr_this_cpu dst=x5, sym=sdei_stack_critical_ptr, tmp=x6
+2: mov x6, #SDEI_STACK_SIZE
+ add x5, x5, x6
+ mov sp, x5
+#endif
+
+ /*
+ * We may have interrupted userspace, or a guest, or exit-from or
+ * return-to either of these. We can't trust sp_el0, restore it.
+ */
+ mrs x28, sp_el0
+ ldr_this_cpu dst=x0, sym=__entry_task, tmp=x1
+ msr sp_el0, x0
+
+ /* If we interrupted the kernel point to the previous stack/frame. */
+ and x0, x3, #0xc
+ mrs x1, CurrentEL
+ cmp x0, x1
+ csel x29, x29, xzr, eq // fp, or zero
+ csel x4, x2, xzr, eq // elr, or zero
+
+ stp x29, x4, [sp, #-16]!
+ mov x29, sp
+
+ add x0, x19, #SDEI_EVENT_INTREGS
+ mov x1, x19
+ bl __sdei_handler
+
+ msr sp_el0, x28
+ /* restore regs >x17 that we clobbered */
+ ldp x28, x29, [x19, #SDEI_EVENT_INTREGS + 16 * 14]
+ ldp lr, x4, [x19, #SDEI_EVENT_INTREGS + S_LR]
+ mov sp, x4
+ ldp x18, x19, [x19, #SDEI_EVENT_INTREGS + 16 * 9]
+
+ mov x1, x0 // address to complete_and_resume
+ /* x0 = (x0 <= 1) ? EVENT_COMPLETE:EVENT_COMPLETE_AND_RESUME */
+ cmp x0, #1
+ mov_q x2, SDEI_1_0_FN_SDEI_EVENT_COMPLETE
+ mov_q x3, SDEI_1_0_FN_SDEI_EVENT_COMPLETE_AND_RESUME
+ csel x0, x2, x3, ls
+
+ /* On success, this call never returns... */
+ ldr_l x2, sdei_exit_mode
+ cmp x2, #SDEI_EXIT_SMC
+ b.ne 1f
+ smc #0
+ b .
+1: hvc #0
+ b .
+ENDPROC(__sdei_asm_handler)
+NOKPROBE(__sdei_asm_handler)
+#endif /* CONFIG_ARM_SDE_INTERFACE */
diff --git a/arch/arm64/kernel/sdei.c b/arch/arm64/kernel/sdei.c
new file mode 100644
index 000000000000..f9dffacaa5d6
--- /dev/null
+++ b/arch/arm64/kernel/sdei.c
@@ -0,0 +1,219 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2017 Arm Ltd.
+#define pr_fmt(fmt) "sdei: " fmt
+
+#include <linux/arm_sdei.h>
+#include <linux/hardirq.h>
+#include <linux/irqflags.h>
+#include <linux/sched/task_stack.h>
+#include <linux/uaccess.h>
+
+#include <asm/alternative.h>
+#include <asm/kprobes.h>
+#include <asm/ptrace.h>
+#include <asm/sysreg.h>
+#include <asm/vmap_stack.h>
+
+unsigned long sdei_exit_mode;
+
+/*
+ * VMAP'd stacks checking for stack overflow on exception using sp as a scratch
+ * register, meaning SDEI has to switch to its own stack. We need two stacks as
+ * a critical event may interrupt a normal event that has just taken a
+ * synchronous exception, and is using sp as scratch register. For a critical
+ * event interrupting a normal event, we can't reliably tell if we were on the
+ * sdei stack.
+ * For now, we allocate stacks when the driver is probed.
+ */
+DECLARE_PER_CPU(unsigned long *, sdei_stack_normal_ptr);
+DECLARE_PER_CPU(unsigned long *, sdei_stack_critical_ptr);
+
+#ifdef CONFIG_VMAP_STACK
+DEFINE_PER_CPU(unsigned long *, sdei_stack_normal_ptr);
+DEFINE_PER_CPU(unsigned long *, sdei_stack_critical_ptr);
+#endif
+
+static void _free_sdei_stack(unsigned long * __percpu *ptr, int cpu)
+{
+ unsigned long *p;
+
+ p = per_cpu(*ptr, cpu);
+ if (p) {
+ per_cpu(*ptr, cpu) = NULL;
+ vfree(p);
+ }
+}
+
+static void free_sdei_stacks(void)
+{
+ int cpu;
+
+ for_each_possible_cpu(cpu) {
+ _free_sdei_stack(&sdei_stack_normal_ptr, cpu);
+ _free_sdei_stack(&sdei_stack_critical_ptr, cpu);
+ }
+}
+
+static int _init_sdei_stack(unsigned long * __percpu *ptr, int cpu)
+{
+ unsigned long *p;
+
+ p = arch_alloc_vmap_stack(SDEI_STACK_SIZE, cpu_to_node(cpu));
+ if (!p)
+ return -ENOMEM;
+ per_cpu(*ptr, cpu) = p;
+
+ return 0;
+}
+
+static int init_sdei_stacks(void)
+{
+ int cpu;
+ int err = 0;
+
+ for_each_possible_cpu(cpu) {
+ err = _init_sdei_stack(&sdei_stack_normal_ptr, cpu);
+ if (err)
+ break;
+ err = _init_sdei_stack(&sdei_stack_critical_ptr, cpu);
+ if (err)
+ break;
+ }
+
+ if (err)
+ free_sdei_stacks();
+
+ return err;
+}
+
+bool _on_sdei_stack(unsigned long sp)
+{
+ unsigned long low, high;
+
+ if (!IS_ENABLED(CONFIG_VMAP_STACK))
+ return false;
+
+ low = (unsigned long)raw_cpu_read(sdei_stack_critical_ptr);
+ high = low + SDEI_STACK_SIZE;
+
+ if (low <= sp && sp < high)
+ return true;
+
+ low = (unsigned long)raw_cpu_read(sdei_stack_normal_ptr);
+ high = low + SDEI_STACK_SIZE;
+
+ return (low <= sp && sp < high);
+}
+
+unsigned long sdei_arch_get_entry_point(int conduit)
+{
+ /*
+ * SDEI works between adjacent exception levels. If we booted at EL1 we
+ * assume a hypervisor is marshalling events. If we booted at EL2 and
+ * dropped to EL1 because we don't support VHE, then we can't support
+ * SDEI.
+ */
+ if (is_hyp_mode_available() && !is_kernel_in_hyp_mode()) {
+ pr_err("Not supported on this hardware/boot configuration\n");
+ return 0;
+ }
+
+ if (IS_ENABLED(CONFIG_VMAP_STACK)) {
+ if (init_sdei_stacks())
+ return 0;
+ }
+
+ sdei_exit_mode = (conduit == CONDUIT_HVC) ? SDEI_EXIT_HVC : SDEI_EXIT_SMC;
+ return (unsigned long)__sdei_asm_handler;
+}
+
+/*
+ * __sdei_handler() returns one of:
+ * SDEI_EV_HANDLED - success, return to the interrupted context.
+ * SDEI_EV_FAILED - failure, return this error code to firmare.
+ * virtual-address - success, return to this address.
+ */
+static __kprobes unsigned long _sdei_handler(struct pt_regs *regs,
+ struct sdei_registered_event *arg)
+{
+ u32 mode;
+ int i, err = 0;
+ const int clobbered_registers = 4;
+ u64 elr = read_sysreg(elr_el1);
+ u32 kernel_mode = read_sysreg(CurrentEL) | 1; /* +SPSel */
+ unsigned long vbar = read_sysreg(vbar_el1);
+
+ /* Retrieve the missing registers values */
+ for (i = 0; i < clobbered_registers; i++) {
+ /* from within the handler, this call always succeeds */
+ sdei_api_event_context(i, &regs->regs[i]);
+ }
+
+ /*
+ * We didn't take an exception to get here, set PAN. UAO will be cleared
+ * by sdei_event_handler()s set_fs(USER_DS) call.
+ */
+ __uaccess_enable_hw_pan();
+
+ err = sdei_event_handler(regs, arg);
+ if (err)
+ return SDEI_EV_FAILED;
+
+ if (elr != read_sysreg(elr_el1)) {
+ /*
+ * We took a synchronous exception from the SDEI handler.
+ * This could deadlock, and if you interrupt KVM it will
+ * hyp-panic instead.
+ */
+ pr_warn("unsafe: exception during handler\n");
+ }
+
+ mode = regs->pstate & (PSR_MODE32_BIT | PSR_MODE_MASK);
+
+ /*
+ * If we interrupted the kernel with interrupts masked, we always go
+ * back to wherever we came from.
+ */
+ if (mode == kernel_mode && !interrupts_enabled(regs))
+ return SDEI_EV_HANDLED;
+
+ /*
+ * Otherwise, we pretend this was an IRQ. This lets user space tasks
+ * receive signals before we return to them, and KVM to invoke it's
+ * world switch to do the same.
+ *
+ * See DDI0487B.a Table D1-7 'Vector offsets from vector table base
+ * address'.
+ */
+ if (mode == kernel_mode)
+ return vbar + 0x280;
+ else if (mode & PSR_MODE32_BIT)
+ return vbar + 0x680;
+
+ return vbar + 0x480;
+}
+
+
+asmlinkage __kprobes notrace unsigned long
+__sdei_handler(struct pt_regs *regs, struct sdei_registered_event *arg)
+{
+ unsigned long ret;
+ bool do_nmi_exit = false;
+
+ /*
+ * nmi_enter() deals with printk() re-entrance and use of RCU when
+ * RCU believed this CPU was idle. Because critical events can
+ * interrupt normal events, we may already be in_nmi().
+ */
+ if (!in_nmi()) {
+ nmi_enter();
+ do_nmi_exit = true;
+ }
+
+ ret = _sdei_handler(regs, arg);
+
+ if (do_nmi_exit)
+ nmi_exit();
+
+ return ret;
+}
diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
index 551eb07c53b6..3b8ad7be9c33 100644
--- a/arch/arm64/kernel/smp.c
+++ b/arch/arm64/kernel/smp.c
@@ -18,6 +18,7 @@
*/
#include <linux/acpi.h>
+#include <linux/arm_sdei.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/spinlock.h>
@@ -836,6 +837,7 @@ static void ipi_cpu_stop(unsigned int cpu)
set_cpu_online(cpu, false);
local_daif_mask();
+ sdei_mask_local_cpu();
while (1)
cpu_relax();
@@ -853,6 +855,7 @@ static void ipi_cpu_crash_stop(unsigned int cpu, struct pt_regs *regs)
atomic_dec(&waiting_for_crash_ipi);
local_irq_disable();
+ sdei_mask_local_cpu();
#ifdef CONFIG_HOTPLUG_CPU
if (cpu_ops[cpu]->cpu_die)
@@ -972,6 +975,8 @@ void smp_send_stop(void)
if (num_online_cpus() > 1)
pr_warning("SMP: failed to stop secondary CPUs %*pbl\n",
cpumask_pr_args(cpu_online_mask));
+
+ sdei_mask_local_cpu();
}
#ifdef CONFIG_KEXEC_CORE
@@ -990,8 +995,10 @@ void crash_smp_send_stop(void)
cpus_stopped = 1;
- if (num_online_cpus() == 1)
+ if (num_online_cpus() == 1) {
+ sdei_mask_local_cpu();
return;
+ }
cpumask_copy(&mask, cpu_online_mask);
cpumask_clear_cpu(smp_processor_id(), &mask);
@@ -1009,6 +1016,8 @@ void crash_smp_send_stop(void)
if (atomic_read(&waiting_for_crash_ipi) > 0)
pr_warning("SMP: failed to stop secondary CPUs %*pbl\n",
cpumask_pr_args(&mask));
+
+ sdei_mask_local_cpu();
}
bool smp_crash_stop_failed(void)
generated by cgit v1.2.3 (git 2.39.0) at 2024-07-12 16:11:56 +0300