arm7/8-m:support all nuttx iamge build with pic

Need to start up a new to setup special registers use
`arm_pic_setupxcp`.

Note that CONFIG_BUILD_PIC compiles the entire NuttX image
as position-independent(PIC), enable CONFIG_PIC to load PIC
application code.

Signed-off-by: anjiahao <anjiahao@xiaomi.com>

Kconfig

@@ -329,6 +329,13 @@ config BUILD_KERNEL
 
 endchoice # Build configuration
 
+config BUILD_PIC
+	bool "NuttX PIC build"
+	default n
+	---help---
+		Builds NuttX with position-independent code (PIC).  This will allow
+		load NuttX into memory at any address and run it.
+
 config BUILD_2PASS
 	bool "Two pass build"
 	default n

arch/arm/include/arch.h

@@ -62,7 +62,7 @@ do { \
     "\tmov %0, " PIC_REG_STRING "\n\t" \
     : "=r"(picbase) \
   ); \
-  *ppicbase = (void *)picbase; \
+  *(uint32_t *)ppicbase = picbase; \
 } while (0)
 
 #define up_setpicbase(picbase) \

arch/arm/src/armv6-m/arm_initialstate.c

@@ -104,6 +104,12 @@ void up_initial_state(struct tcb_s *tcb)
 
   xcp->regs[REG_XPSR]    = ARMV6M_XPSR_T;
 
+  /* All tasks need set to pic address to special register */
+
+#ifdef CONFIG_BUILD_PIC
+  __asm__ ("mov %0, r9" : "=r"(xcp->regs[REG_R9]));
+#endif
+
   /* If this task is running PIC, then set the PIC base register to the
    * address of the allocated D-Space region.
    */

arch/arm/src/armv7-m/arm_initialstate.c

@@ -111,6 +111,12 @@ void up_initial_state(struct tcb_s *tcb)
 
   xcp->regs[REG_XPSR]    = ARMV7M_XPSR_T;
 
+  /* All tasks need set to pic address to special register */
+
+#ifdef CONFIG_BUILD_PIC
+  __asm__ ("mov %0, r9" : "=r"(xcp->regs[REG_R9]));
+#endif
+
   /* If this task is running PIC, then set the PIC base register to the
    * address of the allocated D-Space region.
    */

arch/arm/src/armv8-m/arm_initialstate.c

@@ -117,6 +117,12 @@ void up_initial_state(struct tcb_s *tcb)
 
   xcp->regs[REG_XPSR]    = ARMV8M_XPSR_T;
 
+  /* All tasks need to set pic address to special register */
+
+#ifdef CONFIG_BUILD_PIC
+  __asm__ ("mov %0, r9" : "=r"(xcp->regs[REG_R9]));
+#endif
+
   /* If this task is running PIC, then set the PIC base register to the
    * address of the allocated D-Space region.
    */

arch/arm/src/common/Toolchain.defs

@@ -495,6 +495,14 @@ ifeq ($(CONFIG_LIBCXXTOOLCHAIN),y)
   EXTRA_LIBS += $(wildcard $(shell $(CC) $(ARCHCPUFLAGS) --print-file-name=libstdc++.a))
 endif
 
+PICFLAGS = -fpic -fPIE -mno-pic-data-is-text-relative -msingle-pic-base
+
+ifneq ($(CONFIG_BUILD_PIC),)
+  ARCHCFLAGS += $(PICFLAGS) -mpic-register=r9
+  ARCHCXXFLAGS += $(PICFLAGS) -mpic-register=r9
+  LDFLAGS += --emit-relocs
+endif
+
 # Loadable module definitions
 
 CMODULEFLAGS = $(CFLAGS) -fvisibility=hidden -mlong-calls # --target1-abs
@@ -502,10 +510,13 @@ LDMODULEFLAGS = -r -T $(call CONVERT_PATH,$(TOPDIR)/libs/libc/modlib/gnu-elf.ld)
 
 # ELF module definitions
 
+CELFFLAGS = $(CFLAGS) -fvisibility=hidden -mlong-calls # --target1-abs
+CXXELFFLAGS = $(CXXFLAGS)-fvisibility=hidden
+
 ifeq ($(CONFIG_PIC),y)
   CFLAGS += --fixed-r10
-  PICFLAGS = -fpic -fPIE -mno-pic-data-is-text-relative \
-             -msingle-pic-base -mpic-register=r10
+  CELFFLAGS += $(PICFLAGS) -mpic-register=r10
+  CXXELFFLAGS += $(PICFLAGS) -mpic-register=r10
 
   # Generate an executable elf, need to ignore undefined symbols
   LDELFFLAGS += --unresolved-symbols=ignore-in-object-files --emit-relocs
@@ -513,9 +524,6 @@ else
   LDELFFLAGS += -r
 endif
 
-CELFFLAGS = $(CFLAGS) $(PICFLAGS) -fvisibility=hidden -mlong-calls # --target1-abs
-CXXELFFLAGS = $(CXXFLAGS) $(PICFLAGS) -fvisibility=hidden
-
 LDELFFLAGS +=  -e main -T $(call CONVERT_PATH,$(TOPDIR)$(DELIM)libs$(DELIM)libc$(DELIM)modlib$(DELIM)gnu-elf.ld)
 
 # Zig toolchain