Merge remote-tracking branch 'arm64/for-next/scs' into for-next/core

* arm64/for-next/scs:
  arm64: sdei: Push IS_ENABLED() checks down to callee functions
  arm64: scs: use vmapped IRQ and SDEI shadow stacks
  scs: switch to vmapped shadow stacks

5 files changed, 105 insertions, 25 deletions

diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
index bbaf0bc4ad60..86364ab6f13f 100644
--- a/arch/arm64/kernel/Makefile
+++ b/arch/arm64/kernel/Makefile
@@ -58,7 +58,6 @@ obj-$(CONFIG_CRASH_DUMP)		+= crash_dump.o
 obj-$(CONFIG_CRASH_CORE)		+= crash_core.o
 obj-$(CONFIG_ARM_SDE_INTERFACE)		+= sdei.o
 obj-$(CONFIG_ARM64_PTR_AUTH)		+= pointer_auth.o
-obj-$(CONFIG_SHADOW_CALL_STACK)		+= scs.o
 obj-$(CONFIG_ARM64_MTE)			+= mte.o
 
 obj-y					+= vdso/ probes/
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index 4742a0f3d11a..d61043a00679 100644
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -429,7 +429,7 @@ SYM_CODE_END(__swpan_exit_el0)
 
 #ifdef CONFIG_SHADOW_CALL_STACK
 	/* also switch to the irq shadow stack */
-	adr_this_cpu scs_sp, irq_shadow_call_stack, x26
+	ldr_this_cpu scs_sp, irq_shadow_call_stack_ptr, x26
 #endif
 
 9998:
@@ -1086,9 +1086,9 @@ SYM_CODE_START(__sdei_asm_handler)
 #ifdef CONFIG_SHADOW_CALL_STACK
 	/* Use a separate shadow call stack for normal and critical events */
 	cbnz	w4, 3f
-	adr_this_cpu dst=scs_sp, sym=sdei_shadow_call_stack_normal, tmp=x6
+	ldr_this_cpu dst=scs_sp, sym=sdei_shadow_call_stack_normal_ptr, tmp=x6
 	b	4f
-3:	adr_this_cpu dst=scs_sp, sym=sdei_shadow_call_stack_critical, tmp=x6
+3:	ldr_this_cpu dst=scs_sp, sym=sdei_shadow_call_stack_critical_ptr, tmp=x6
 4:
 #endif
 
diff --git a/arch/arm64/kernel/irq.c b/arch/arm64/kernel/irq.c
index 9cf2fb87584a..ac54c21140d4 100644
--- a/arch/arm64/kernel/irq.c
+++ b/arch/arm64/kernel/irq.c
@@ -17,6 +17,7 @@
 #include <linux/init.h>
 #include <linux/irqchip.h>
 #include <linux/kprobes.h>
+#include <linux/scs.h>
 #include <linux/seq_file.h>
 #include <linux/vmalloc.h>
 #include <asm/daifflags.h>
@@ -27,6 +28,25 @@ DEFINE_PER_CPU(struct nmi_ctx, nmi_contexts);
 
 DEFINE_PER_CPU(unsigned long *, irq_stack_ptr);
 
+
+DECLARE_PER_CPU(unsigned long *, irq_shadow_call_stack_ptr);
+
+#ifdef CONFIG_SHADOW_CALL_STACK
+DEFINE_PER_CPU(unsigned long *, irq_shadow_call_stack_ptr);
+#endif
+
+static void init_irq_scs(void)
+{
+	int cpu;
+
+	if (!IS_ENABLED(CONFIG_SHADOW_CALL_STACK))
+		return;
+
+	for_each_possible_cpu(cpu)
+		per_cpu(irq_shadow_call_stack_ptr, cpu) =
+			scs_alloc(cpu_to_node(cpu));
+}
+
 #ifdef CONFIG_VMAP_STACK
 static void init_irq_stacks(void)
 {
@@ -54,6 +74,7 @@ static void init_irq_stacks(void)
 void __init init_IRQ(void)
 {
 	init_irq_stacks();
+	init_irq_scs();
 	irqchip_init();
 	if (!handle_arch_irq)
 		panic("No interrupt controller found.");
diff --git a/arch/arm64/kernel/scs.c b/arch/arm64/kernel/scs.c
deleted file mode 100644
index e8f7ff45dd8f..000000000000
--- a/arch/arm64/kernel/scs.c
+++ /dev/null
@@ -1,16 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-/*
- * Shadow Call Stack support.
- *
- * Copyright (C) 2019 Google LLC
- */
-
-#include <linux/percpu.h>
-#include <linux/scs.h>
-
-DEFINE_SCS(irq_shadow_call_stack);
-
-#ifdef CONFIG_ARM_SDE_INTERFACE
-DEFINE_SCS(sdei_shadow_call_stack_normal);
-DEFINE_SCS(sdei_shadow_call_stack_critical);
-#endif
diff --git a/arch/arm64/kernel/sdei.c b/arch/arm64/kernel/sdei.c
index e04b3e90c003..35298f4e3faf 100644
--- a/arch/arm64/kernel/sdei.c
+++ b/arch/arm64/kernel/sdei.c
@@ -7,6 +7,7 @@
 #include <linux/hardirq.h>
 #include <linux/irqflags.h>
 #include <linux/sched/task_stack.h>
+#include <linux/scs.h>
 #include <linux/uaccess.h>
 
 #include <asm/alternative.h>
@@ -37,6 +38,14 @@ DEFINE_PER_CPU(unsigned long *, sdei_stack_normal_ptr);
 DEFINE_PER_CPU(unsigned long *, sdei_stack_critical_ptr);
 #endif
 
+DECLARE_PER_CPU(unsigned long *, sdei_shadow_call_stack_normal_ptr);
+DECLARE_PER_CPU(unsigned long *, sdei_shadow_call_stack_critical_ptr);
+
+#ifdef CONFIG_SHADOW_CALL_STACK
+DEFINE_PER_CPU(unsigned long *, sdei_shadow_call_stack_normal_ptr);
+DEFINE_PER_CPU(unsigned long *, sdei_shadow_call_stack_critical_ptr);
+#endif
+
 static void _free_sdei_stack(unsigned long * __percpu *ptr, int cpu)
 {
 	unsigned long *p;
@@ -52,6 +61,9 @@ static void free_sdei_stacks(void)
 {
 	int cpu;
 
+	if (!IS_ENABLED(CONFIG_VMAP_STACK))
+		return;
+
 	for_each_possible_cpu(cpu) {
 		_free_sdei_stack(&sdei_stack_normal_ptr, cpu);
 		_free_sdei_stack(&sdei_stack_critical_ptr, cpu);
@@ -75,6 +87,9 @@ static int init_sdei_stacks(void)
 	int cpu;
 	int err = 0;
 
+	if (!IS_ENABLED(CONFIG_VMAP_STACK))
+		return 0;
+
 	for_each_possible_cpu(cpu) {
 		err = _init_sdei_stack(&sdei_stack_normal_ptr, cpu);
 		if (err)
@@ -90,6 +105,62 @@ static int init_sdei_stacks(void)
 	return err;
 }
 
+static void _free_sdei_scs(unsigned long * __percpu *ptr, int cpu)
+{
+	void *s;
+
+	s = per_cpu(*ptr, cpu);
+	if (s) {
+		per_cpu(*ptr, cpu) = NULL;
+		scs_free(s);
+	}
+}
+
+static void free_sdei_scs(void)
+{
+	int cpu;
+
+	for_each_possible_cpu(cpu) {
+		_free_sdei_scs(&sdei_shadow_call_stack_normal_ptr, cpu);
+		_free_sdei_scs(&sdei_shadow_call_stack_critical_ptr, cpu);
+	}
+}
+
+static int _init_sdei_scs(unsigned long * __percpu *ptr, int cpu)
+{
+	void *s;
+
+	s = scs_alloc(cpu_to_node(cpu));
+	if (!s)
+		return -ENOMEM;
+	per_cpu(*ptr, cpu) = s;
+
+	return 0;
+}
+
+static int init_sdei_scs(void)
+{
+	int cpu;
+	int err = 0;
+
+	if (!IS_ENABLED(CONFIG_SHADOW_CALL_STACK))
+		return 0;
+
+	for_each_possible_cpu(cpu) {
+		err = _init_sdei_scs(&sdei_shadow_call_stack_normal_ptr, cpu);
+		if (err)
+			break;
+		err = _init_sdei_scs(&sdei_shadow_call_stack_critical_ptr, cpu);
+		if (err)
+			break;
+	}
+
+	if (err)
+		free_sdei_scs();
+
+	return err;
+}
+
 static bool on_sdei_normal_stack(unsigned long sp, struct stack_info *info)
 {
 	unsigned long low = (unsigned long)raw_cpu_read(sdei_stack_normal_ptr);
@@ -130,13 +201,14 @@ unsigned long sdei_arch_get_entry_point(int conduit)
 	 */
 	if (is_hyp_mode_available() && !is_kernel_in_hyp_mode()) {
 		pr_err("Not supported on this hardware/boot configuration\n");
-		return 0;
+		goto out_err;
 	}
 
-	if (IS_ENABLED(CONFIG_VMAP_STACK)) {
-		if (init_sdei_stacks())
-			return 0;
-	}
+	if (init_sdei_stacks())
+		goto out_err;
+
+	if (init_sdei_scs())
+		goto out_err_free_stacks;
 
 	sdei_exit_mode = (conduit == SMCCC_CONDUIT_HVC) ? SDEI_EXIT_HVC : SDEI_EXIT_SMC;
 
@@ -151,6 +223,10 @@ unsigned long sdei_arch_get_entry_point(int conduit)
 #endif /* CONFIG_UNMAP_KERNEL_AT_EL0 */
 		return (unsigned long)__sdei_asm_handler;
 
+out_err_free_stacks:
+	free_sdei_stacks();
+out_err:
+	return 0;
 }
 
 /*