[PATCH v2 1/1] riscv: additional crash information

[Heinrich Schuchardt]

If an exception occurs, the relocated program counter and return address
are required for an analysis.

With this patch you get:

    => exception undefined

    Unhandled exception: Illegal instruction
    EPC: 0000000080595908 RA: 000000008059c0c6 TVAL: 000000008030c01e
    EPC: 0000000080007908 RA: 000000008000e0c6 reloc adjusted

We can use the relocated addresses to find the involved functions in
u.boot.map:

    .text.do_undefined
                0x0000000080007908        0x8 cmd/built-in.o
    .text.cmd_process
                0x000000008000dfcc      0x11a common/built-in.o
                0x000000008000dfcc                cmd_process

If an exception occurs in an UEFI binary additionally the load addresses of
the UEFI binaries are needed. With this patch:

    => setenv efi_selftest exception
    => bootefi selftest

    Unhandled exception: Illegal instruction
    EPC: 000000008042e18a RA: 000000008042e18a TVAL: 000000008030c01e
    EPC: 000000007fea018a RA: 000000007fea018a reloc adjusted

    UEFI image [0x0000000000000000:0xffffffffffffffff] '/\selftest'
    UEFI image [0x000000008042e000:0x000000008042e43f] pc=0x18a '/bug.efi'

The value pc=0x18a matches the position of the illegal instruction in
efi_selftest_miniapp_exception.efi (loaded as /bug.efi);

    asm volatile (".word 0xffffffff\n");

    00000180   93 85 C5 11  1C 64 22 85  82 97 FF FF  FF FF 1C 64

Signed-off-by: Heinrich Schuchardt <xypron.glpk at gmx.de>
Reviewed-by: Sean Anderson <seanga2 at gmail.com>
Tested-by: Sean Anderson <seanga2 at gmail.com>
---
v2:
	description of relocated addresses: %s/reloc/reloc adjusted/
---
 arch/riscv/lib/interrupts.c | 57 +++++++++++++++++++++++--------------
 1 file changed, 35 insertions(+), 22 deletions(-)

diff --git a/arch/riscv/lib/interrupts.c b/arch/riscv/lib/interrupts.c
index 074c70ee77..cd47e64487 100644
--- a/arch/riscv/lib/interrupts.c
+++ b/arch/riscv/lib/interrupts.c
@@ -10,36 +10,43 @@
  */

 #include <common.h>
+#include <efi_loader.h>
 #include <hang.h>
 #include <irq_func.h>
 #include <asm/ptrace.h>
 #include <asm/system.h>
 #include <asm/encoding.h>

+DECLARE_GLOBAL_DATA_PTR;
+
+static void show_efi_loaded_images(uintptr_t epc)
+{
+	efi_print_image_infos((void *)epc);
+}
+
 static void show_regs(struct pt_regs *regs)
 {
 #ifdef CONFIG_SHOW_REGS
-	printf("RA: " REG_FMT " SP:  " REG_FMT " GP:  " REG_FMT "\n",
-	       regs->ra, regs->sp, regs->gp);
-	printf("TP: " REG_FMT " T0:  " REG_FMT " T1:  " REG_FMT "\n",
-	       regs->tp, regs->t0, regs->t1);
-	printf("T2: " REG_FMT " S0:  " REG_FMT " S1:  " REG_FMT "\n",
-	       regs->t2, regs->s0, regs->s1);
-	printf("A0: " REG_FMT " A1:  " REG_FMT " A2:  " REG_FMT "\n",
-	       regs->a0, regs->a1, regs->a2);
-	printf("A3: " REG_FMT " A4:  " REG_FMT " A5:  " REG_FMT "\n",
-	       regs->a3, regs->a4, regs->a5);
-	printf("A6: " REG_FMT " A7:  " REG_FMT " S2:  " REG_FMT "\n",
-	       regs->a6, regs->a7, regs->s2);
-	printf("S3: " REG_FMT " S4:  " REG_FMT " S5:  " REG_FMT "\n",
-	       regs->s3, regs->s4, regs->s5);
-	printf("S6: " REG_FMT " S7:  " REG_FMT " S8:  " REG_FMT "\n",
-	       regs->s6, regs->s7, regs->s8);
-	printf("S9: " REG_FMT " S10: " REG_FMT " S11: " REG_FMT "\n",
-	       regs->s9, regs->s10, regs->s11);
-	printf("T3: " REG_FMT " T4:  " REG_FMT " T5:  " REG_FMT "\n",
-	       regs->t3, regs->t4, regs->t5);
-	printf("T6: " REG_FMT "\n", regs->t6);
+	printf("SP:  " 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",
+	       regs->t0, regs->t1, regs->t2);
+	printf("S0:  " REG_FMT " S1:  " REG_FMT " A0:  " REG_FMT "\n",
+	       regs->s0, regs->s1, regs->a0);
+	printf("A1:  " REG_FMT " A2:  " REG_FMT " A3:  " REG_FMT "\n",
+	       regs->a1, regs->a2, regs->a3);
+	printf("A4:  " REG_FMT " A5:  " REG_FMT " A6:  " REG_FMT "\n",
+	       regs->a4, regs->a5, regs->a6);
+	printf("A7:  " REG_FMT " S2:  " REG_FMT " S3:  " REG_FMT "\n",
+	       regs->a7, regs->s2, regs->s3);
+	printf("S4:  " REG_FMT " S5:  " REG_FMT " S6:  " REG_FMT "\n",
+	       regs->s4, regs->s5, regs->s6);
+	printf("S7:  " REG_FMT " S8:  " REG_FMT " S9:  " REG_FMT "\n",
+	       regs->s7, regs->s8, regs->s9);
+	printf("S10: " REG_FMT " S11: " REG_FMT " T3:  " REG_FMT "\n",
+	       regs->s10, regs->s11, regs->t3);
+	printf("T4:  " REG_FMT " T5:  " REG_FMT " T6:  " REG_FMT "\n\n",
+	       regs->t4, regs->t5, regs->t6);
 #endif
 }

@@ -69,8 +76,14 @@ static void _exit_trap(ulong code, ulong epc, ulong tval, struct pt_regs *regs)
 	else
 		printf("Unhandled exception code: %ld\n", code);

-	printf("EPC: " REG_FMT " TVAL: " REG_FMT "\n", epc, tval);
+	printf("EPC: " REG_FMT " RA: " REG_FMT " TVAL: " REG_FMT "\n",
+	       epc, regs->ra, tval);
+	if (gd->flags & GD_FLG_RELOC)
+		printf("EPC: " REG_FMT " RA: " REG_FMT " reloc adjusted\n\n",
+		       epc - gd->reloc_off, regs->ra - gd->reloc_off);
+
 	show_regs(regs);
+	show_efi_loaded_images(epc);
 	hang();
 }

--
2.27.0