Use scs_alloc() to allocate also IRQ and SDEI shadow stacks instead of
using statically allocated stacks.

Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
---
 arch/arm64/include/asm/scs.h | 21 ++++++++++-
 arch/arm64/kernel/entry.S    |  6 ++--
 arch/arm64/kernel/irq.c      |  2 ++
 arch/arm64/kernel/scs.c      | 67 +++++++++++++++++++++++++++++++++---
 arch/arm64/kernel/sdei.c     |  7 ++++
 include/linux/scs.h          |  8 ++---
 kernel/scs.c                 |  4 +--
 7 files changed, 101 insertions(+), 14 deletions(-)

diff --git a/arch/arm64/include/asm/scs.h b/arch/arm64/include/asm/scs.h
index eaa2cd92e4c1..e9d2c3e67ff9 100644
--- a/arch/arm64/include/asm/scs.h
+++ b/arch/arm64/include/asm/scs.h

@@ -24,6 +24,25 @@
 	.endm
 #endif /* CONFIG_SHADOW_CALL_STACK */
 
-#endif /* __ASSEMBLY __ */
+#else /* __ASSEMBLY__ */
+
+#include <linux/scs.h>
+
+#ifdef CONFIG_SHADOW_CALL_STACK
+
+extern void scs_init_irq(void);
+
+extern void scs_free_sdei(void);

diff --git a/arch/arm64/kernel/irq.c b/arch/arm64/kernel/irq.c
index 9cf2fb87584a..54ba3725bc0e 100644
--- a/arch/arm64/kernel/irq.c
+++ b/arch/arm64/kernel/irq.c

@@ -20,6 +20,7 @@
 #include <linux/seq_file.h>
 #include <linux/vmalloc.h>
 #include <asm/daifflags.h>
+#include <asm/scs.h>
 #include <asm/vmap_stack.h>
 
 /* Only access this in an NMI enter/exit */

@@ -54,6 +55,7 @@ static void init_irq_stacks(void)
 void __init init_IRQ(void)
 {
 	init_irq_stacks();
+	scs_init_irq();

diff --git a/arch/arm64/kernel/sdei.c b/arch/arm64/kernel/sdei.c
index 7689f2031c0c..04519a7cb51d 100644
--- a/arch/arm64/kernel/sdei.c
+++ b/arch/arm64/kernel/sdei.c

@@ -13,6 +13,7 @@
 #include <asm/kprobes.h>
 #include <asm/mmu.h>
 #include <asm/ptrace.h>
+#include <asm/scs.h>
 #include <asm/sections.h>
 #include <asm/stacktrace.h>
 #include <asm/sysreg.h>

@@ -138,6 +139,12 @@ unsigned long sdei_arch_get_entry_point(int conduit)
 			return 0;
 	}
 
+	if (scs_init_sdei()) {

diff --git a/include/linux/scs.h b/include/linux/scs.h
index 86e3c4b7b714..6b35a83576d4 100644
--- a/include/linux/scs.h
+++ b/include/linux/scs.h

@@ -21,13 +21,11 @@
 /* An illegal pointer value to mark the end of the shadow stack. */
 #define SCS_END_MAGIC		(0x5f6UL + POISON_POINTER_DELTA)
 
-/* Allocate a static per-CPU shadow stack */
-#define DEFINE_SCS(name)						\
-	DEFINE_PER_CPU(unsigned long [SCS_SIZE/sizeof(long)], name)	\
-
 #define task_scs(tsk)		(task_thread_info(tsk)->scs_base)
 #define task_scs_sp(tsk)	(task_thread_info(tsk)->scs_sp)
 
+void *scs_alloc(int node);
+void scs_free(void *s);
 void scs_init(void);
 int scs_prepare(struct task_struct *tsk, int node);
 void scs_release(struct task_struct *tsk);

@@ -56,6 +54,8 @@ static inline bool task_scs_end_corrupted(struct task_struct *tsk)
 
 #else /* CONFIG_SHADOW_CALL_STACK */
 
+static inline void *scs_alloc(int node) { return NULL; }
+static inline void scs_free(void *s) {}
 static inline void scs_init(void) {}
 static inline void scs_task_reset(struct task_struct *tsk) {}
 static inline int scs_prepare(struct task_struct *tsk, int node) { return 0; }

diff --git a/kernel/scs.c b/kernel/scs.c
index 2136edba548d..8df4a92cd939 100644
--- a/kernel/scs.c
+++ b/kernel/scs.c

@@ -24,7 +24,7 @@ static void __scs_account(void *s, int account)
 #define NR_CACHED_SCS 2
 static DEFINE_PER_CPU(void *, scs_cache[NR_CACHED_SCS]);
 
-static void *scs_alloc(int node)
+void *scs_alloc(int node)
 {
 	int i;
 	void *s;

@@ -63,7 +63,7 @@ static void *scs_alloc(int node)
 	return s;
 }
 
-static void scs_free(void *s)
+void scs_free(void *s)