[PATCH 08/24] RISC-V sim: Add brk syscall.

[Jim Wilson <jimw@sifive.com>]

From: Kuan-Lin Chen <rufus@andestech.com>

Add endbrk field to cpu struct.  Set it to highest section end address.
Use it for the brk syscall support.

	sim/riscv/
	* interp.c: Include libiberty.h, bfd.h, and elf-bfd.h.
	(sim_create_inferior): New locals phdr, i, phnum.  Use to
	calculate cpu->endbrk.
	* sim-main.c (execute_i): In case MATCH_ECALL, handle
	TARGET_SYS_brk.
	* sim-main.h (struct _sim_cpu): Add endbrk field.
---
 sim/riscv/interp.c   | 15 +++++++++++++++
 sim/riscv/sim-main.c |  9 +++++++++
 sim/riscv/sim-main.h |  1 +
 3 files changed, 25 insertions(+)

diff --git a/sim/riscv/interp.c b/sim/riscv/interp.c
index 1bf60a4..c98f6ab 100644
--- a/sim/riscv/interp.c
+++ b/sim/riscv/interp.c
@@ -20,6 +20,10 @@
 
 #include "config.h"
 
+#include "libiberty.h"
+#include "bfd.h"
+#include "elf-bfd.h"
+
 #include "sim-main.h"
 #include "sim-options.h"
 \f
@@ -129,6 +133,8 @@ sim_create_inferior (SIM_DESC sd, struct bfd *abfd,
 {
   SIM_CPU *cpu = STATE_CPU (sd, 0);
   SIM_ADDR addr;
+  Elf_Internal_Phdr *phdr;
+  int i, phnum;
 
   /* Set the PC.  */
   if (abfd != NULL)
@@ -137,6 +143,15 @@ sim_create_inferior (SIM_DESC sd, struct bfd *abfd,
     addr = 0;
   sim_pc_set (cpu, addr);
 
+  /* Set endbrk to highest section end address.  */
+  phdr = elf_tdata (abfd)->phdr;
+  phnum = elf_elfheader (abfd)->e_phnum;
+  for (i = 0; i < phnum; i++)
+    {
+      if (phdr[i].p_paddr + phdr[i].p_memsz > cpu->endbrk)
+	cpu->endbrk = phdr[i].p_paddr + phdr[i].p_memsz;
+    }
+
   /* Standalone mode (i.e. `run`) will take care of the argv for us in
      sim_open() -> sim_parse_args().  But in debug mode (i.e. 'target sim'
      with `gdb`), we need to handle it because the user can change the
diff --git a/sim/riscv/sim-main.c b/sim/riscv/sim-main.c
index 03ba79b..597e9c3 100644
--- a/sim/riscv/sim-main.c
+++ b/sim/riscv/sim-main.c
@@ -1274,6 +1274,15 @@ execute_i (SIM_CPU *cpu, unsigned_word iw, const struct riscv_opcode *op)
 		cpu->a0 = link (oldpath, newpath);
 		break;
 	      }
+	    case TARGET_SYS_brk:
+	      {
+		/* FIXME: Check the invalid access.  */
+		if (cpu->a0 == 0)
+		  cpu->a0 = cpu->endbrk;
+		else
+		  cpu->endbrk = cpu->a0;
+		break;
+	      }
 	    default:
 	      cpu->a0 = -1;
 	      break;
diff --git a/sim/riscv/sim-main.h b/sim/riscv/sim-main.h
index e53794f..9206b94 100644
--- a/sim/riscv/sim-main.h
+++ b/sim/riscv/sim-main.h
@@ -63,6 +63,7 @@ struct _sim_cpu {
     };
   };
   sim_cia pc;
+  sim_cia endbrk;
 
   struct {
 #define DECLARE_CSR(name, ...) unsigned_word name;
-- 
2.7.4