[Qemu-devel] [PATCH 2/2] ppc: Add dump-stack implementation

[Suraj Jitindar Singh <sjitindarsingh@gmail.com>]

The monitor function dump-stack is used to dump the stack for a cpu.
This can be useful for debugging purposes when the stack cannot be
dumped by another means.

Add a ppc implementation ppc_cpu_dump_stack().
The stack pointer is stored in R1 with the back pointer at offset 0 and
the link register at offset 2.
Also dump the registers from the stack frame if the marker "regshere" is
found.
This only dumps the kernel stack, stopping if a non-kernel address is
found in the stack.

Sample output:
(qemu) dump-stack
sp: 0xc00000007bfc5690 lr: 0xc0000000000974b8
sp: 0xc00000007bfc56f0 lr: 0xc00000000065aab4
sp: 0xc00000007bfc5720 lr: 0xc00000000065ab04
sp: 0xc00000007bfc5740 lr: 0xc0000000000c29b8
sp: 0xc00000007bfc57b0 lr: 0xc0000000000bc9e8
sp: 0xc00000007bfc57e0 lr: 0xc0000000000bd584
sp: 0xc00000007bfc5800 lr: 0xc0000000000bee14
sp: 0xc00000007bfc5ac0 lr: 0xc0000000000c2100
sp: 0xc00000007bfc5c60 lr: 0xc000000000029460
sp: 0xc00000007bfc5ca0 lr: 0xc00000000010b5e8
sp: 0xc00000007bfc5d00 lr: 0xc000000000105f34
	trap : 0x0000000000000700
	pc   : 0xc000000000104490
	msr  : 0x9000000002843003
	lr   : 0xc000000000103ffc
	gpr 0: 0x0000000000000001
	gpr 1: 0xc00000005051f530
	gpr 2: 0xc000000001088200
	gpr 3: 0x0000000000000001
	gpr 4: 0xc000000032d60000
	gpr 5: 0xc0000000014b8f00
	gpr 6: 0x0000000000c835e0
	gpr 7: 0x0000000000000000
	gpr 8: 0x0000000000000000
	gpr 9: 0xc000000032f00000
	gpr10: 0x9000000002803033
	gpr11: 0xc000000000b60f00
	gpr12: 0x0000000000002000
	gpr13: 0xc000000001250000
	gpr14: 0x0000000000000000
	gpr15: 0x0000000000000008
	gpr16: 0x0000000000000000
	gpr17: 0xc00000000114f790
	gpr18: 0x00000000ffffffff
	gpr19: 0xc00000005051f8e8
	gpr20: 0x0000000000000001
	gpr21: 0x0000000000000000
	gpr22: 0x0000000000000001
	gpr23: 0x0000000000000001
	gpr24: 0x0000000000000001
	gpr25: 0xc0000000014b8f70
	gpr26: 0x0000000000000000
	gpr27: 0x0000000000000001
	gpr28: 0x0000000000000001
	gpr29: 0x0000000000000000
	gpr30: 0xc0000000014b8f00
	gpr31: 0xc0000000014b8f00
sp: 0xc00000005051f530 lr: 0x0000000000000000
sp: 0xc00000005051f600 lr: 0xc000000000103ffc
sp: 0xc00000005051f670 lr: 0xc0000000000f60a8
sp: 0xc00000005051f850 lr: 0xc0000000000f18c0
sp: 0xc00000005051fa10 lr: 0xc0000000000f5184
sp: 0xc00000005051fae0 lr: 0xc0000000000ddf54
sp: 0xc00000005051fb00 lr: 0xc0000000000dab9c
sp: 0xc00000005051fb90 lr: 0xc0000000000cbf88
sp: 0xc00000005051fd00 lr: 0xc0000000003e7480
sp: 0xc00000005051fdb0 lr: 0xc0000000003e7ce4
sp: 0xc00000005051fe00 lr: 0xc0000000003e7d88
sp: 0xc00000005051fe20 lr: 0xc00000000000b3a4
	trap : 0x0000000000000c01
	pc   : 0x00007fffa6c9d8d0
	msr  : 0x900000000280f033
	lr   : 0x0000000010090f40
	gpr 0: 0x0000000000000036
	gpr 1: 0x00007fffa62fdd70
	gpr 2: 0x00007fffa6d57300
	gpr 3: 0x000000000000000d
	gpr 4: 0x000000002000ae80
	gpr 5: 0x0000000000000000
	gpr 6: 0x0000000000000537
	gpr 7: 0x0000000000000000
	gpr 8: 0x000000000000000d
	gpr 9: 0x0000000000000000
	gpr10: 0x0000000000000000
	gpr11: 0x0000000000000000
	gpr12: 0x0000000000000000
	gpr13: 0x00007fffa6306380
	gpr14: 0x0000000000000000
	gpr15: 0x0000000000000001
	gpr16: 0x0000000039ba6928
	gpr17: 0x0000000000000000
	gpr18: 0x0000000000000000
	gpr19: 0x00007fffa6d702f0
	gpr20: 0x00007fffa62fddf0
	gpr21: 0x0000000000000080
	gpr22: 0x0000000000000004
	gpr23: 0x0000000000000000
	gpr24: 0x0000000010ac85c0
	gpr25: 0x0000000000000008
	gpr26: 0x00007fffa62fde10
	gpr27: 0x0000000000000000
	gpr28: 0x0000000000000002
	gpr29: 0x0000000000000000
	gpr30: 0x0000000039ba6900
	gpr31: 0x0000000010ac85c0
sp: 0x00007fffa62fdd70

Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com>
---
 target/ppc/cpu.h                |  1 +
 target/ppc/translate.c          | 60 +++++++++++++++++++++++++++++++++++++++++
 target/ppc/translate_init.inc.c |  1 +
 3 files changed, 62 insertions(+)

diff --git a/target/ppc/cpu.h b/target/ppc/cpu.h
index 5e7cf54b2f..28c4dffca1 100644
--- a/target/ppc/cpu.h
+++ b/target/ppc/cpu.h
@@ -1284,6 +1284,7 @@ struct PPCVirtualHypervisorClass {
 void ppc_cpu_do_interrupt(CPUState *cpu);
 bool ppc_cpu_exec_interrupt(CPUState *cpu, int int_req);
 void ppc_cpu_dump_state(CPUState *cpu, FILE *f, int flags);
+void ppc_cpu_dump_stack(CPUState *cpu, FILE *f);
 void ppc_cpu_dump_statistics(CPUState *cpu, int flags);
 hwaddr ppc_cpu_get_phys_page_debug(CPUState *cpu, vaddr addr);
 int ppc_cpu_gdb_read_register(CPUState *cpu, uint8_t *buf, int reg);
diff --git a/target/ppc/translate.c b/target/ppc/translate.c
index 8d08625c33..b162998ce7 100644
--- a/target/ppc/translate.c
+++ b/target/ppc/translate.c
@@ -7705,6 +7705,66 @@ void ppc_cpu_dump_state(CPUState *cs, FILE *f, int flags)
 #undef RFPL
 }
 
+struct ppc_pt_regs {
+        unsigned long gpr[32];
+        unsigned long nip;
+        unsigned long msr;
+        unsigned long orig_gpr3;
+        unsigned long ctr;
+        unsigned long link;
+        unsigned long xer;
+        unsigned long ccr;
+        unsigned long softe;
+        unsigned long trap;
+        unsigned long dar;
+        unsigned long dsisr;
+        unsigned long result;
+};
+
+void ppc_cpu_dump_stack(CPUState *cs, FILE *f)
+{
+#if defined(TARGET_PPC64)
+    PowerPCCPU *cpu = POWERPC_CPU(cs);
+    CPUPPCState *env = &cpu->env;
+    uint64_t sp, next_sp, lr, buf[4];
+
+    /* stack pointer stored in r1 */
+    sp = env->gpr[1];
+
+    while (sp && (sp & (0xCUL << 60))) {
+        uint64_t marker = 0UL;
+
+        /* read and print LR */
+        cpu_physical_memory_read(sp & ~(0xCUL << 60), buf, sizeof(*buf) * 4);
+        next_sp = buf[0];
+        lr = buf[2];
+        qemu_fprintf(f, "sp: 0x%.16lx lr: 0x%.16lx\n", sp, lr);
+        sp &= ~(0xCUL << 60);
+
+        /* Does the stackframe contain regs? */
+        cpu_physical_memory_read(sp + 96, &marker, sizeof(marker));
+        if (marker == 0x7265677368657265) { /* regshere */
+            struct ppc_pt_regs regs;
+            int i;
+
+            cpu_physical_memory_read(sp + 112, &regs, sizeof(regs));
+
+            qemu_fprintf(f, "\ttrap : 0x%.16lx\n", regs.trap);
+            qemu_fprintf(f, "\tpc   : 0x%.16lx\n", regs.nip);
+            qemu_fprintf(f, "\tmsr  : 0x%.16lx\n", regs.msr);
+            qemu_fprintf(f, "\tlr   : 0x%.16lx\n", regs.link);
+            for (i = 0; i < 32; i++)
+                qemu_fprintf(f, "\tgpr%2d: 0x%.16lx\n", i,
+                            regs.gpr[i]);
+        }
+
+        sp = next_sp;
+    }
+
+    qemu_fprintf(f, "sp: 0x%.16lx\n", sp);
+#endif
+}
+
 void ppc_cpu_dump_statistics(CPUState *cs, int flags)
 {
 #if defined(DO_PPC_STATISTICS)
diff --git a/target/ppc/translate_init.inc.c b/target/ppc/translate_init.inc.c
index 0394a9ddad..3fd24f85cc 100644
--- a/target/ppc/translate_init.inc.c
+++ b/target/ppc/translate_init.inc.c
@@ -10587,6 +10587,7 @@ static void ppc_cpu_class_init(ObjectClass *oc, void *data)
     cc->do_interrupt = ppc_cpu_do_interrupt;
     cc->cpu_exec_interrupt = ppc_cpu_exec_interrupt;
     cc->dump_state = ppc_cpu_dump_state;
+    cc->dump_stack = ppc_cpu_dump_stack;
     cc->dump_statistics = ppc_cpu_dump_statistics;
     cc->set_pc = ppc_cpu_set_pc;
     cc->gdb_read_register = ppc_cpu_gdb_read_register;
-- 
2.13.6