parisc: Move thread_info into task struct

This implements the CONFIG_THREAD_INFO_IN_TASK option.

With this change:
- before thread_info was part of the stack and located at the beginning of the stack
- now the thread_info struct is moved and located inside the task_struct structure
- the stack is allocated and handled like the major other platforms
- drop the cpu field of thread_info and use instead the one in task_struct

Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sven Schnelle <svens@stackframe.org>

4 files changed, 36 insertions, 11 deletions

diff --git a/arch/parisc/include/asm/current.h b/arch/parisc/include/asm/current.h
new file mode 100644
index 000000000000..568b739e42af
--- /dev/null
+++ b/arch/parisc/include/asm/current.h
@@ -0,0 +1,19 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_PARISC_CURRENT_H
+#define _ASM_PARISC_CURRENT_H
+
+#include <asm/special_insns.h>
+
+#ifndef __ASSEMBLY__
+struct task_struct;
+
+static __always_inline struct task_struct *get_current(void)
+{
+	return (struct task_struct *) mfctl(30);
+}
+
+#define current get_current()
+
+#endif /* __ASSEMBLY__ */
+
+#endif /* _ASM_PARISC_CURRENT_H */
diff --git a/arch/parisc/include/asm/processor.h b/arch/parisc/include/asm/processor.h
index f57944d3284b..0d567774f506 100644
--- a/arch/parisc/include/asm/processor.h
+++ b/arch/parisc/include/asm/processor.h
@@ -102,8 +102,6 @@ DECLARE_PER_CPU(struct cpuinfo_parisc, cpu_data);
 
 #define CPU_HVERSION ((boot_cpu_data.hversion >> 4) & 0x0FFF)
 
-#define ARCH_MIN_TASKALIGN	FRAME_ALIGN
-
 struct thread_struct {
 	struct pt_regs regs;
 	unsigned long  task_size;
diff --git a/arch/parisc/include/asm/smp.h b/arch/parisc/include/asm/smp.h
index b9a18db4b05a..16d41127500e 100644
--- a/arch/parisc/include/asm/smp.h
+++ b/arch/parisc/include/asm/smp.h
@@ -34,8 +34,23 @@ extern void arch_send_call_function_ipi_mask(const struct cpumask *mask);
 
 #endif /* !ASSEMBLY */
 
-#define raw_smp_processor_id()	(current_thread_info()->cpu)
-
+/*
+ * This is particularly ugly: it appears we can't actually get the definition
+ * of task_struct here, but we need access to the CPU this task is running on.
+ * Instead of using task_struct we're using TASK_CPU which is extracted from
+ * asm-offsets.h by kbuild to get the current processor ID.
+ *
+ * This also needs to be safeguarded when building asm-offsets.s because at
+ * that time TASK_CPU is not defined yet. It could have been guarded by
+ * TASK_CPU itself, but we want the build to fail if TASK_CPU is missing
+ * when building something else than asm-offsets.s
+ */
+#ifdef GENERATING_ASM_OFFSETS
+#define raw_smp_processor_id()		(0)
+#else
+#include <asm/asm-offsets.h>
+#define raw_smp_processor_id()		(*(unsigned int *)((void *)current + TASK_CPU))
+#endif
 #else /* CONFIG_SMP */
 
 static inline void smp_send_all_nop(void) { return; }
diff --git a/arch/parisc/include/asm/thread_info.h b/arch/parisc/include/asm/thread_info.h
index 00ad50fef769..4617303e0620 100644
--- a/arch/parisc/include/asm/thread_info.h
+++ b/arch/parisc/include/asm/thread_info.h
@@ -9,23 +9,16 @@
 #include <asm/special_insns.h>
 
 struct thread_info {
-	struct task_struct *task;	/* main task structure */
 	unsigned long flags;		/* thread_info flags (see TIF_*) */
-	__u32 cpu;			/* current CPU */
 	int preempt_count;		/* 0=premptable, <0=BUG; will also serve as bh-counter */
 };
 
 #define INIT_THREAD_INFO(tsk)			\
 {						\
-	.task		= &tsk,			\
 	.flags		= 0,			\
-	.cpu		= 0,			\
 	.preempt_count	= INIT_PREEMPT_COUNT,	\
 }
 
-/* how to get the thread information struct from C */
-#define current_thread_info()	((struct thread_info *)mfctl(30))
-
 #endif /* !__ASSEMBLY */
 
 /* thread information allocation */