@@ -30,6 +30,9 @@ config DMA_ADDR_T_64BIT
bool
default y if 64BIT
+config SHOW_REGS
+ bool "Show registers on unhandled exception"
+
config STACK_SIZE_SHIFT
int
default 14
@@ -6,4 +6,4 @@
extra-y = start.o
obj-y += cpu.o
-obj-y += smp_secondary.o
+obj-y += smp_secondary.o genex.o
new file mode 100644
@@ -0,0 +1,21 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Exception entry for LoongArch CPU
+ *
+ * Copyright (C) 2024 Jiaxun Yang <jiaxun.yang@flygoat.com>
+ */
+
+#include <linux/linkage.h>
+#include <asm/asm.h>
+#include <asm/loongarch.h>
+#include <asm/stackframe.h>
+
+.align 12
+ENTRY(exception_entry)
+ BACKUP_T0T1
+ SAVE_ALL
+ move a0, sp
+ la.pcrel t0, do_exceptions
+ jirl ra, t0, 0
+ RESTORE_ALL_AND_RET
+END(exception_entry)
new file mode 100644
@@ -0,0 +1,175 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
+ * Copyright (C) 2024 Jiaxun Yang <jiaxun.yang@flygoat.com>
+ */
+#ifndef _ASM_STACKFRAME_H
+#define _ASM_STACKFRAME_H
+
+#include <asm/addrspace.h>
+#include <asm/asm.h>
+#include <generated/asm-offsets.h>
+#include <asm/loongarch.h>
+
+/* Make the addition of cfi info a little easier. */
+ .macro cfi_rel_offset reg offset=0 docfi=0
+ .if \docfi
+ .cfi_rel_offset \reg, \offset
+ .endif
+ .endm
+
+ .macro cfi_st reg offset=0 docfi=0
+ cfi_rel_offset \reg, \offset, \docfi
+ LONG_S \reg, sp, \offset
+ .endm
+
+ .macro cfi_restore reg offset=0 docfi=0
+ .if \docfi
+ .cfi_restore \reg
+ .endif
+ .endm
+
+ .macro cfi_ld reg offset=0 docfi=0
+ LONG_L \reg, sp, \offset
+ cfi_restore \reg \offset \docfi
+ .endm
+
+ .macro BACKUP_T0T1
+ csrwr t0, EXCEPTION_KS0
+ csrwr t1, EXCEPTION_KS1
+ .endm
+
+ .macro RELOAD_T0T1
+ csrrd t0, EXCEPTION_KS0
+ csrrd t1, EXCEPTION_KS1
+ .endm
+
+ .macro SAVE_TEMP docfi=0
+ RELOAD_T0T1
+ cfi_st t0, PT_R12, \docfi
+ cfi_st t1, PT_R13, \docfi
+ cfi_st t2, PT_R14, \docfi
+ cfi_st t3, PT_R15, \docfi
+ cfi_st t4, PT_R16, \docfi
+ cfi_st t5, PT_R17, \docfi
+ cfi_st t6, PT_R18, \docfi
+ cfi_st t7, PT_R19, \docfi
+ cfi_st t8, PT_R20, \docfi
+ .endm
+
+ .macro SAVE_STATIC docfi=0
+ cfi_st s0, PT_R23, \docfi
+ cfi_st s1, PT_R24, \docfi
+ cfi_st s2, PT_R25, \docfi
+ cfi_st s3, PT_R26, \docfi
+ cfi_st s4, PT_R27, \docfi
+ cfi_st s5, PT_R28, \docfi
+ cfi_st s6, PT_R29, \docfi
+ cfi_st s7, PT_R30, \docfi
+ cfi_st s8, PT_R31, \docfi
+ .endm
+
+ .macro SAVE_SOME docfi=0
+ PTR_ADDI sp, sp, -PT_SIZE
+ .if \docfi
+ .cfi_def_cfa sp, 0
+ .endif
+ cfi_st t0, PT_R3, \docfi
+ cfi_rel_offset sp, PT_R3, \docfi
+ LONG_S zero, sp, PT_R0
+ csrrd t0, LOONGARCH_CSR_PRMD
+ LONG_S t0, sp, PT_PRMD
+ csrrd t0, LOONGARCH_CSR_CRMD
+ LONG_S t0, sp, PT_CRMD
+ csrrd t0, LOONGARCH_CSR_EUEN
+ LONG_S t0, sp, PT_EUEN
+ csrrd t0, LOONGARCH_CSR_ECFG
+ LONG_S t0, sp, PT_ECFG
+ csrrd t0, LOONGARCH_CSR_ESTAT
+ PTR_S t0, sp, PT_ESTAT
+ cfi_st ra, PT_R1, \docfi
+ cfi_st a0, PT_R4, \docfi
+ cfi_st a1, PT_R5, \docfi
+ cfi_st a2, PT_R6, \docfi
+ cfi_st a3, PT_R7, \docfi
+ cfi_st a4, PT_R8, \docfi
+ cfi_st a5, PT_R9, \docfi
+ cfi_st a6, PT_R10, \docfi
+ cfi_st a7, PT_R11, \docfi
+ csrrd ra, LOONGARCH_CSR_ERA
+ LONG_S ra, sp, PT_ERA
+ .if \docfi
+ .cfi_rel_offset ra, PT_ERA
+ .endif
+ cfi_st tp, PT_R2, \docfi
+ cfi_st fp, PT_R22, \docfi
+ /* Save U0 for sanity */
+ cfi_st u0, PT_R21, \docfi
+ .endm
+
+ .macro SAVE_ALL docfi=0
+ SAVE_SOME \docfi
+ SAVE_TEMP \docfi
+ SAVE_STATIC \docfi
+ .endm
+
+ .macro RESTORE_TEMP docfi=0
+ cfi_ld t0, PT_R12, \docfi
+ cfi_ld t1, PT_R13, \docfi
+ cfi_ld t2, PT_R14, \docfi
+ cfi_ld t3, PT_R15, \docfi
+ cfi_ld t4, PT_R16, \docfi
+ cfi_ld t5, PT_R17, \docfi
+ cfi_ld t6, PT_R18, \docfi
+ cfi_ld t7, PT_R19, \docfi
+ cfi_ld t8, PT_R20, \docfi
+ .endm
+
+ .macro RESTORE_STATIC docfi=0
+ cfi_ld s0, PT_R23, \docfi
+ cfi_ld s1, PT_R24, \docfi
+ cfi_ld s2, PT_R25, \docfi
+ cfi_ld s3, PT_R26, \docfi
+ cfi_ld s4, PT_R27, \docfi
+ cfi_ld s5, PT_R28, \docfi
+ cfi_ld s6, PT_R29, \docfi
+ cfi_ld s7, PT_R30, \docfi
+ cfi_ld s8, PT_R31, \docfi
+ .endm
+
+ .macro RESTORE_SOME docfi=0
+ LONG_L a0, sp, PT_PRMD
+ andi a0, a0, 0x3 /* extract pplv bit */
+ beqz a0, 8f
+ cfi_ld u0, PT_R21, \docfi
+8:
+ LONG_L a0, sp, PT_ERA
+ csrwr a0, LOONGARCH_CSR_ERA
+ LONG_L a0, sp, PT_PRMD
+ csrwr a0, LOONGARCH_CSR_PRMD
+ cfi_ld ra, PT_R1, \docfi
+ cfi_ld a0, PT_R4, \docfi
+ cfi_ld a1, PT_R5, \docfi
+ cfi_ld a2, PT_R6, \docfi
+ cfi_ld a3, PT_R7, \docfi
+ cfi_ld a4, PT_R8, \docfi
+ cfi_ld a5, PT_R9, \docfi
+ cfi_ld a6, PT_R10, \docfi
+ cfi_ld a7, PT_R11, \docfi
+ cfi_ld tp, PT_R2, \docfi
+ cfi_ld fp, PT_R22, \docfi
+ .endm
+
+ .macro RESTORE_SP_AND_RET docfi=0
+ cfi_ld sp, PT_R3, \docfi
+ ertn
+ .endm
+
+ .macro RESTORE_ALL_AND_RET docfi=0
+ RESTORE_STATIC \docfi
+ RESTORE_TEMP \docfi
+ RESTORE_SOME \docfi
+ RESTORE_SP_AND_RET \docfi
+ .endm
+
+#endif /* _ASM_STACKFRAME_H */
new file mode 100644
@@ -0,0 +1,189 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2024 Jiaxun Yang <jiaxun.yang@flygoat.com>
+ */
+
+#include <linux/compat.h>
+#include <linux/bitfield.h>
+#include <linux/linkage.h>
+#include <hang.h>
+#include <interrupt.h>
+#include <irq_func.h>
+#include <asm/global_data.h>
+#include <asm/ptrace.h>
+#include <asm/system.h>
+#include <asm/regdef.h>
+#include <asm/loongarch.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+static struct resume_data *resume;
+
+void set_resume(struct resume_data *data)
+{
+ resume = data;
+}
+
+static void show_regs(struct pt_regs *regs)
+{
+#if IS_ENABLED(CONFIG_SHOW_REGS)
+ const int field = 2 * sizeof(unsigned long);
+
+#define GPR_FIELD(x) field, regs->regs[x]
+ printf("pc %0*lx ra %0*lx tp %0*lx sp %0*lx\n",
+ field, regs->csr_era, GPR_FIELD(1), GPR_FIELD(2), GPR_FIELD(3));
+ printf("a0 %0*lx a1 %0*lx a2 %0*lx a3 %0*lx\n",
+ GPR_FIELD(4), GPR_FIELD(5), GPR_FIELD(6), GPR_FIELD(7));
+ printf("a4 %0*lx a5 %0*lx a6 %0*lx a7 %0*lx\n",
+ GPR_FIELD(8), GPR_FIELD(9), GPR_FIELD(10), GPR_FIELD(11));
+ printf("t0 %0*lx t1 %0*lx t2 %0*lx t3 %0*lx\n",
+ GPR_FIELD(12), GPR_FIELD(13), GPR_FIELD(14), GPR_FIELD(15));
+ printf("t4 %0*lx t5 %0*lx t6 %0*lx t7 %0*lx\n",
+ GPR_FIELD(16), GPR_FIELD(17), GPR_FIELD(18), GPR_FIELD(19));
+ printf("t8 %0*lx u0 %0*lx s9 %0*lx s0 %0*lx\n",
+ GPR_FIELD(20), GPR_FIELD(21), GPR_FIELD(22), GPR_FIELD(23));
+ printf("s1 %0*lx s2 %0*lx s3 %0*lx s4 %0*lx\n",
+ GPR_FIELD(24), GPR_FIELD(25), GPR_FIELD(26), GPR_FIELD(27));
+ printf("s5 %0*lx s6 %0*lx s7 %0*lx s8 %0*lx\n",
+ GPR_FIELD(28), GPR_FIELD(29), GPR_FIELD(30), GPR_FIELD(31));
+#endif
+}
+
+static void __maybe_unused show_backtrace(struct pt_regs *regs)
+{
+ uintptr_t *fp = (uintptr_t *)regs->regs[0x16];
+ unsigned int count = 0;
+ ulong ra;
+
+ printf("\nbacktrace:\n");
+
+ /*
+ * there are a few entry points where the s0 register is
+ * set to gd, so to avoid changing those, just abort if
+ * the value is the same.
+ */
+ while (fp != NULL && fp != (uintptr_t *)gd) {
+ ra = fp[-1];
+ printf("%3d: fp: " REG_FMT " ra: " REG_FMT,
+ count, (ulong)fp, ra);
+
+ if (gd && gd->flags & GD_FLG_RELOC)
+ printf(" - ra: " REG_FMT " reloc adjusted\n",
+ ra - gd->reloc_off);
+ else
+ printf("\n");
+
+ fp = (uintptr_t *)fp[-2];
+ count++;
+ }
+}
+
+static const char *humanize_exc_name(unsigned int ecode, unsigned int esubcode)
+{
+ /*
+ * LoongArch users and developers are probably more familiar with
+ * those names found in the ISA manual, so we are going to print out
+ * the latter. This will require some mapping.
+ */
+ switch (ecode) {
+ case EXCCODE_RSV: return "INT";
+ case EXCCODE_TLBL: return "PIL";
+ case EXCCODE_TLBS: return "PIS";
+ case EXCCODE_TLBI: return "PIF";
+ case EXCCODE_TLBM: return "PME";
+ case EXCCODE_TLBNR: return "PNR";
+ case EXCCODE_TLBNX: return "PNX";
+ case EXCCODE_TLBPE: return "PPI";
+ case EXCCODE_ADE:
+ switch (esubcode) {
+ case EXSUBCODE_ADEF: return "ADEF";
+ case EXSUBCODE_ADEM: return "ADEM";
+ }
+ break;
+ case EXCCODE_ALE: return "ALE";
+ case EXCCODE_BCE: return "BCE";
+ case EXCCODE_SYS: return "SYS";
+ case EXCCODE_BP: return "BRK";
+ case EXCCODE_INE: return "INE";
+ case EXCCODE_IPE: return "IPE";
+ case EXCCODE_FPDIS: return "FPD";
+ case EXCCODE_LSXDIS: return "SXD";
+ case EXCCODE_LASXDIS: return "ASXD";
+ case EXCCODE_FPE:
+ switch (esubcode) {
+ case EXCSUBCODE_FPE: return "FPE";
+ case EXCSUBCODE_VFPE: return "VFPE";
+ }
+ break;
+ case EXCCODE_WATCH:
+ switch (esubcode) {
+ case EXCSUBCODE_WPEF: return "WPEF";
+ case EXCSUBCODE_WPEM: return "WPEM";
+ }
+ break;
+ case EXCCODE_BTDIS: return "BTD";
+ case EXCCODE_BTE: return "BTE";
+ case EXCCODE_GSPR: return "GSPR";
+ case EXCCODE_HVC: return "HVC";
+ case EXCCODE_GCM:
+ switch (esubcode) {
+ case EXCSUBCODE_GCSC: return "GCSC";
+ case EXCSUBCODE_GCHC: return "GCHC";
+ }
+ break;
+ /*
+ * The manual did not mention the EXCCODE_SE case, but print out it
+ * nevertheless.
+ */
+ case EXCCODE_SE: return "SE";
+ }
+
+ return "???";
+}
+
+asmlinkage void do_exceptions(struct pt_regs *regs)
+{
+ unsigned int ecode = FIELD_GET(CSR_ESTAT_EXC, regs->csr_estat);
+ unsigned int esubcode = FIELD_GET(CSR_ESTAT_ESUBCODE, regs->csr_estat);
+
+ printf("Unhandled exception: %s\n", humanize_exc_name(ecode, esubcode));
+
+ printf("ERA: " REG_FMT " ra: " REG_FMT "\n",
+ regs->csr_era, regs->regs[1]);
+ /* Print relocation adjustments, but only if gd is initialized */
+ if (gd && gd->flags & GD_FLG_RELOC)
+ printf("ERA: " REG_FMT " ra: " REG_FMT " reloc adjusted\n",
+ regs->csr_era - gd->reloc_off, regs->regs[1] - gd->reloc_off);
+
+ printf("CRMD: " REG_FMT "\n", regs->csr_crmd);
+ if (ecode >= EXCCODE_TLBL && ecode <= EXCCODE_ALE)
+ printf("BADV: " REG_FMT "\n", regs->csr_badvaddr);
+
+ printf("\n");
+ show_regs(regs);
+
+ if (CONFIG_IS_ENABLED(FRAMEPOINTER))
+ show_backtrace(regs);
+
+ panic("\n");
+}
+
+int interrupt_init(void)
+{
+ return 0;
+}
+
+/*
+ * enable interrupts
+ */
+void enable_interrupts(void)
+{
+}
+
+/*
+ * disable interrupts
+ */
+int disable_interrupts(void)
+{
+ return 0;
+}
Add exception entry assembly code, import stackframe.h from Linux, provide debug prints when exception happens. Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com> --- arch/loongarch/Kconfig | 3 + arch/loongarch/cpu/Makefile | 2 +- arch/loongarch/cpu/genex.S | 21 ++++ arch/loongarch/include/asm/stackframe.h | 175 +++++++++++++++++++++++++++++ arch/loongarch/lib/interrupts.c | 189 ++++++++++++++++++++++++++++++++ 5 files changed, 389 insertions(+), 1 deletion(-)