335 lines
11 KiB
Diff
335 lines
11 KiB
Diff
From d86dc6901ce76a0fc29022ed448a4baa83a47dd7 Mon Sep 17 00:00:00 2001
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From: Song Shuai <songshuaishuai@tinylab.org>
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Date: Wed, 13 Dec 2023 17:45:06 +0800
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Subject: [PATCH 2/6] RISCV64: Add support for 'bt -e' option
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With this patch we can search the stack for possible kernel and user
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mode exception frames via 'bt -e' command.
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TEST: a lkdtm DIRECT EXCEPTION vmcore
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crash> bt -e
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PID: 1 TASK: ff600000000e0000 CPU: 1 COMMAND: "sh"
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KERNEL-MODE EXCEPTION FRAME AT: ff200000000138d8
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PC: ffffffff805303c0 [lkdtm_EXCEPTION+6]
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RA: ffffffff8052fe36 [lkdtm_do_action+16]
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SP: ff20000000013cf0 CAUSE: 000000000000000f
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epc : ffffffff805303c0 ra : ffffffff8052fe36 sp : ff20000000013cf0
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gp : ffffffff814ef848 tp : ff600000000e0000 t0 : 6500000000000000
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t1 : 000000000000006c t2 : 6550203a6d74646b s0 : ff20000000013d00
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s1 : 000000000000000a a0 : ffffffff814aef40 a1 : c0000000ffffefff
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a2 : 0000000000000010 a3 : 0000000000000001 a4 : 5d53ea10ca096e00
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a5 : ffffffff805303ba a6 : 0000000000000008 a7 : 0000000000000038
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s2 : ff60000001324000 s3 : ffffffff814aef40 s4 : ff20000000013e30
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s5 : 000000000000000a s6 : ff20000000013e30 s7 : ff600000000ce000
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s8 : 0000555560f0f8a8 s9 : 00007ffff497f6b4 s10: 00007ffff497f6b0
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s11: 0000555560fa30e0 t3 : ffffffff81502197 t4 : ffffffff81502197
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t5 : ffffffff81502198 t6 : ff20000000013b28
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status: 0000000200000120 badaddr: 0000000000000000
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cause: 000000000000000f orig_a0: 0000000000000000
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USER-MODE EXCEPTION FRAME AT: ff20000000013ee0
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PC: 007fff8780431aff RA: 007fff877b168400 SP: 007ffff497f5b000
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ORIG_A0: 0000000000000100 SYSCALLNO: 0000000000004000
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epc : 007fff8780431aff ra : 007fff877b168400 sp : 007ffff497f5b000
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gp : 00555560f5134800 tp : 007fff8774378000 t0 : 0000000000100000
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t1 : 00555560e427bc00 t2 : 0000000000271000 s0 : 007ffff497f5e000
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s1 : 0000000000000a00 a0 : 0000000000000100 a1 : 00555560faa68000
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a2 : 0000000000000a00 a3 : 4000000000000000 a4 : 20000000000000a8
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a5 : 0000000000000054 a6 : 0000000000000400 a7 : 0000000000004000
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s2 : 00555560faa68000 s3 : 007fff878b33f800 s4 : 0000000000000a00
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s5 : 00555560faa68000 s6 : 0000000000000a00 s7 : 00555560f5131400
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s8 : 00555560f0f8a800 s9 : 007ffff497f6b400 s10: 007ffff497f6b000
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s11: 00555560fa30e000 t3 : 007fff877af1fe00 t4 : 00555560fa6f2000
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t5 : 0000000000000100 t6 : 9e1fea5bf8683300
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status: 00000200004020b9 badaddr: 0000000000000000
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cause: 0000000000000800 orig_a0: 0000000000000100
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crash>
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Signed-off-by: Song Shuai <songshuaishuai@tinylab.org>
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Signed-off-by: Lianbo Jiang <lijiang@redhat.com>
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---
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defs.h | 15 +++--
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riscv64.c | 191 +++++++++++++++++++++++++++++++++++++++++++++++++-----
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2 files changed, 181 insertions(+), 25 deletions(-)
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diff --git a/defs.h b/defs.h
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index aa8eba83b7f4..9cf9501348ed 100644
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--- a/defs.h
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+++ b/defs.h
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@@ -7011,17 +7011,16 @@ int riscv64_IS_VMALLOC_ADDR(ulong);
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#define display_idt_table() \
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error(FATAL, "-d option is not applicable to RISCV64 architecture\n")
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-/* from arch/riscv/include/asm/ptrace.h */
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+/*
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+ * regs[0,31] : struct user_regs_struct
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+ * from arch/riscv/include/uapi/asm/ptrace.h
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+ * regs[0,35] : struct pt_regs
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+ * from arch/riscv/include/asm/ptrace.h
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+ */
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struct riscv64_register {
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ulong regs[36];
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};
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-struct riscv64_pt_regs {
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- ulong badvaddr;
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- ulong cause;
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- ulong epc;
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-};
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-
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struct riscv64_unwind_frame {
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ulong fp;
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ulong sp;
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@@ -7085,6 +7084,8 @@ struct machine_specific {
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#define RISCV64_REGS_RA 1
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#define RISCV64_REGS_SP 2
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#define RISCV64_REGS_FP 8
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+#define RISCV64_REGS_STATUS 32
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+#define RISCV64_REGS_CAUSE 34
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#endif /* RISCV64 */
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diff --git a/riscv64.c b/riscv64.c
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index 872be594d72b..6097c0029ccc 100644
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--- a/riscv64.c
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+++ b/riscv64.c
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@@ -35,6 +35,7 @@ static int riscv64_kvtop(struct task_context *tc, ulong kvaddr,
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static void riscv64_cmd_mach(void);
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static void riscv64_stackframe_init(void);
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static void riscv64_back_trace_cmd(struct bt_info *bt);
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+static int riscv64_eframe_search(struct bt_info *bt);
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static int riscv64_get_dumpfile_stack_frame(struct bt_info *bt,
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ulong *nip, ulong *ksp);
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static void riscv64_get_stack_frame(struct bt_info *bt, ulong *pcp,
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@@ -51,6 +52,8 @@ static int riscv64_get_elf_notes(void);
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static void riscv64_get_va_range(struct machine_specific *ms);
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static void riscv64_get_va_bits(struct machine_specific *ms);
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static void riscv64_get_struct_page_size(struct machine_specific *ms);
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+static void riscv64_print_exception_frame(struct bt_info *, ulong , int );
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+static int riscv64_is_kernel_exception_frame(struct bt_info *, ulong );
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#define REG_FMT "%016lx"
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#define SZ_2G 0x80000000
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@@ -210,6 +213,7 @@ riscv64_dump_machdep_table(ulong arg)
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machdep->memsize, machdep->memsize);
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fprintf(fp, " bits: %d\n", machdep->bits);
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fprintf(fp, " back_trace: riscv64_back_trace_cmd()\n");
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+ fprintf(fp, " eframe_search: riscv64_eframe_search()\n");
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fprintf(fp, " processor_speed: riscv64_processor_speed()\n");
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fprintf(fp, " uvtop: riscv64_uvtop()\n");
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fprintf(fp, " kvtop: riscv64_kvtop()\n");
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@@ -1398,6 +1402,7 @@ riscv64_init(int when)
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machdep->cmd_mach = riscv64_cmd_mach;
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machdep->get_stack_frame = riscv64_get_stack_frame;
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machdep->back_trace = riscv64_back_trace_cmd;
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+ machdep->eframe_search = riscv64_eframe_search;
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machdep->vmalloc_start = riscv64_vmalloc_start;
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machdep->processor_speed = riscv64_processor_speed;
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@@ -1452,25 +1457,10 @@ riscv64_init(int when)
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}
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}
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-/*
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- * 'help -r' command output
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- */
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-void
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-riscv64_display_regs_from_elf_notes(int cpu, FILE *ofp)
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+/* bool pt_regs : pass 1 to dump pt_regs , pass 0 to dump user_regs_struct */
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+static void
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+riscv64_dump_pt_regs(struct riscv64_register *regs, FILE *ofp, bool pt_regs)
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{
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- const struct machine_specific *ms = machdep->machspec;
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- struct riscv64_register *regs;
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-
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- if (!ms->crash_task_regs) {
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- error(INFO, "registers not collected for cpu %d\n", cpu);
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- return;
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- }
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-
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- regs = &ms->crash_task_regs[cpu];
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- if (!regs->regs[RISCV64_REGS_SP] && !regs->regs[RISCV64_REGS_EPC]) {
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- error(INFO, "registers not collected for cpu %d\n", cpu);
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- return;
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- }
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/* Print riscv64 32 regs */
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fprintf(ofp,
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@@ -1496,6 +1486,171 @@ riscv64_display_regs_from_elf_notes(int cpu, FILE *ofp)
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regs->regs[24], regs->regs[25], regs->regs[26],
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regs->regs[27], regs->regs[28], regs->regs[29],
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regs->regs[30], regs->regs[31]);
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+
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+ if (pt_regs)
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+ fprintf(ofp,
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+ " status: " REG_FMT " badaddr: " REG_FMT "\n"
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+ " cause: " REG_FMT " orig_a0: " REG_FMT "\n",
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+ regs->regs[32], regs->regs[33], regs->regs[34],
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+ regs->regs[35]);
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+}
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+
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+/*
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+ * 'help -r' command output
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+ */
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+void
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+riscv64_display_regs_from_elf_notes(int cpu, FILE *ofp)
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+{
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+ const struct machine_specific *ms = machdep->machspec;
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+ struct riscv64_register *regs;
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+
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+ if (!ms->crash_task_regs) {
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+ error(INFO, "registers not collected for cpu %d\n", cpu);
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+ return;
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+ }
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+
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+ regs = &ms->crash_task_regs[cpu];
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+ if (!regs->regs[RISCV64_REGS_SP] && !regs->regs[RISCV64_REGS_EPC]) {
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+ error(INFO, "registers not collected for cpu %d\n", cpu);
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+ return;
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+ }
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+
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+ riscv64_dump_pt_regs(regs, ofp, 0);
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+}
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+
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+#define USER_MODE (0)
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+#define KERNEL_MODE (1)
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+
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+static void
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+riscv64_print_exception_frame(struct bt_info *bt, ulong ptr, int mode)
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+{
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+
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+ struct syment *sp;
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+ ulong PC, RA, SP, offset;
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+ struct riscv64_register *regs;
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+
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+ regs = (struct riscv64_register *)&bt->stackbuf[(ulong)(STACK_OFFSET_TYPE(ptr))];
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+
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+ PC = regs->regs[RISCV64_REGS_EPC];
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+ RA = regs->regs[RISCV64_REGS_RA];
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+ SP = regs->regs[RISCV64_REGS_SP];
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+
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+ switch (mode) {
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+ case USER_MODE:
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+ fprintf(fp,
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+ " PC: %016lx RA: %016lx SP: %016lx\n"
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+ " ORIG_A0: %016lx SYSCALLNO: %016lx\n",
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+ PC, RA, SP, regs->regs[35], regs->regs[17]);
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+
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+ break;
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+
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+ case KERNEL_MODE:
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+ fprintf(fp, " PC: %016lx ", PC);
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+ if (is_kernel_text(PC) && (sp = value_search(PC, &offset))) {
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+ fprintf(fp, "[%s", sp->name);
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+ if (offset)
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+ fprintf(fp, (*gdb_output_radix == 16) ?
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+ "+0x%lx" : "+%ld", offset);
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+ fprintf(fp, "]\n");
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+ } else
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+ fprintf(fp, "[unknown or invalid address]\n");
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+
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+ fprintf(fp, " RA: %016lx ", RA);
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+ if (is_kernel_text(RA) && (sp = value_search(RA, &offset))) {
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+ fprintf(fp, "[%s", sp->name);
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+ if (offset)
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+ fprintf(fp, (*gdb_output_radix == 16) ?
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+ "+0x%lx" : "+%ld", offset);
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+ fprintf(fp, "]\n");
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+ } else
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+ fprintf(fp, "[unknown or invalid address]\n");
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+
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+ fprintf(fp, " SP: %016lx CAUSE: %016lx\n",
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+ SP, regs->regs[RISCV64_REGS_CAUSE]);
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+
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+ break;
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+ }
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+
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+ riscv64_dump_pt_regs(regs, fp, 1);
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+
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+}
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+
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+static int
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+riscv64_is_kernel_exception_frame(struct bt_info *bt, ulong stkptr)
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+{
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+ struct riscv64_register *regs;
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+
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+ if (stkptr > STACKSIZE() && !INSTACK(stkptr, bt)) {
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+ if (CRASHDEBUG(1))
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+ error(WARNING, "stkptr: %lx is outside the kernel stack range\n", stkptr);
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+ return FALSE;
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+ }
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+
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+ regs = (struct riscv64_register *)&bt->stackbuf[(ulong)(STACK_OFFSET_TYPE(stkptr))];
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+
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+ if (INSTACK(regs->regs[RISCV64_REGS_SP], bt) &&
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+ INSTACK(regs->regs[RISCV64_REGS_FP], bt) &&
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+ is_kernel_text(regs->regs[RISCV64_REGS_RA]) &&
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+ is_kernel_text(regs->regs[RISCV64_REGS_EPC]) &&
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+ ((regs->regs[RISCV64_REGS_STATUS] >> 8) & 0x1) && // sstatus.SPP != 0
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+ !((regs->regs[RISCV64_REGS_CAUSE] >> 63) & 0x1 ) && // scause.Interrupt != 1
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+ !(regs->regs[RISCV64_REGS_CAUSE] == 0x00000008UL)) { // scause != ecall from U-mode
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+
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+ return TRUE;
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+ }
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+
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+ return FALSE;
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+}
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+
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+static int
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+riscv64_dump_kernel_eframes(struct bt_info *bt)
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+{
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+ ulong ptr;
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+ int count;
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+
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+ /*
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+ * use old_regs to avoid the identical contiguous kernel exception frames
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+ * created by Linux handle_exception() path ending at riscv_crash_save_regs()
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+ */
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+ struct riscv64_register *regs, *old_regs;
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+
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+ count = 0;
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+ old_regs = NULL;
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+
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+ for (ptr = bt->stackbase; ptr < bt->stacktop - SIZE(pt_regs); ptr++) {
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+
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+ regs = (struct riscv64_register *)&bt->stackbuf[(ulong)(STACK_OFFSET_TYPE(ptr))];
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+
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+ if (riscv64_is_kernel_exception_frame(bt, ptr)){
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+ if (!old_regs || (old_regs &&
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+ memcmp(old_regs, regs, sizeof(struct riscv64_register))) != 0){
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+ old_regs = regs;
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+ fprintf(fp, "\nKERNEL-MODE EXCEPTION FRAME AT: %lx\n", ptr);
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+ riscv64_print_exception_frame(bt, ptr, KERNEL_MODE);
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+ count++;
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+ }
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+ }
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+ }
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+
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+ return count;
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+}
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+
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+static int
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+riscv64_eframe_search(struct bt_info *bt)
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+{
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+ ulong ptr;
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+ int count;
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+
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+ count = riscv64_dump_kernel_eframes(bt);
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+
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+ if (is_kernel_thread(bt->tc->task))
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+ return count;
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+
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+ ptr = bt->stacktop - SIZE(pt_regs);
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+ fprintf(fp, "%sUSER-MODE EXCEPTION FRAME AT: %lx\n", count++ ? "\n" : "", ptr);
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+ riscv64_print_exception_frame(bt, ptr, USER_MODE);
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+
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+ return count;
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}
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#else /* !RISCV64 */
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--
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2.41.0
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