riscv: allow to enable SHOW_REGS in main U-Boot only

To minimize SPL size it is reasonable to disable SHOW_REGS. For main U-Boot
the size restrictions are much more relaxed.

* Provide separate Kconfig symbols for SPL and main U-Boot.
* Add a help text.

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Reviewed-by: Leo Yu-Chi Liang <ycliang@andestech.com>
diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 4e228a6..fd1f5f8 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -439,6 +439,18 @@
 
 config SHOW_REGS
 	bool "Show registers on unhandled exception"
+	help
+	  By default only the program counter and the return address register
+	  are shown in crash dumps. Enable this symbol to show all registers in
+	  main U-Boot.
+
+config SPL_SHOW_REGS
+	bool "In SPL show registers on unhandled exception"
+	depends on SPL
+	help
+	  By default only the program counter and the return address register
+	  are shown in crash dumps. Enable this symbol to show all registers in
+	  SPL.
 
 config RISCV_PRIV_1_9
 	bool "Use version 1.9 of the RISC-V priviledged specification"
diff --git a/arch/riscv/lib/interrupts.c b/arch/riscv/lib/interrupts.c
index f9a1428..714cc92 100644
--- a/arch/riscv/lib/interrupts.c
+++ b/arch/riscv/lib/interrupts.c
@@ -34,9 +34,8 @@
 	efi_print_image_infos((void *)epc);
 }
 
-static void show_regs(struct pt_regs *regs)
+static void __maybe_unused show_regs(struct pt_regs *regs)
 {
-#ifdef CONFIG_SHOW_REGS
 	printf("\nSP:  " REG_FMT " GP:  " REG_FMT " TP:  " REG_FMT "\n",
 	       regs->sp, regs->gp, regs->tp);
 	printf("T0:  " REG_FMT " T1:  " REG_FMT " T2:  " REG_FMT "\n",
@@ -57,7 +56,6 @@
 	       regs->s10, regs->s11, regs->t3);
 	printf("T4:  " REG_FMT " T5:  " REG_FMT " T6:  " REG_FMT "\n",
 	       regs->t4, regs->t5, regs->t6);
-#endif
 }
 
 static void __maybe_unused show_backtrace(struct pt_regs *regs)
@@ -157,7 +155,8 @@
 		printf("EPC: " REG_FMT " RA: " REG_FMT " reloc adjusted\n",
 		       epc - gd->reloc_off, regs->ra - gd->reloc_off);
 
-	show_regs(regs);
+	if (CONFIG_IS_ENABLED(SHOW_REGS))
+		show_regs(regs);
 	if (CONFIG_IS_ENABLED(FRAMEPOINTER))
 		show_backtrace(regs);
 	show_code(epc);