Re: [PATCH v3] sim: mips: Add handlers to simulator monitor for unlink, lseek and stat

[Mike Frysinger via Gdb-patches <gdb-patches@sourceware.org>]

lgtm!  not sure if Maciej wants to take a pass.
-mike

On 31 Mar 2021 12:40, Faraz Shahbazker wrote:
> sim/mips/ChangeLog
> 	* interp.c (sim_monitor): Add switch entries for unlink (13),
> 	lseek (14), and stat (15).
> 
> Derived from patch authored by Steve Ellcey <sellcey@mips.com>
> ---
> 
> Notes:
>     Changes from v2:
>     - remove call to abort() on cb_syscall failure
>     - capture return value of call in V0
> 
>  sim/mips/ChangeLog |  6 ++++
>  sim/mips/interp.c  | 70 +++++++++++++++++++++++++++++++++++++++++++++-
>  2 files changed, 75 insertions(+), 1 deletion(-)
> 
> diff --git a/sim/mips/ChangeLog b/sim/mips/ChangeLog
> index 12347a7e3e2..56464eb6727 100644
> --- a/sim/mips/ChangeLog
> +++ b/sim/mips/ChangeLog
> @@ -1,3 +1,9 @@
> +2021-03-31  Steve Ellcey  <sellcey@mips.com>
> +	    Faraz Shahbazker  <fshahbazker@wavecomp.com>
> +
> +	* interp.c (sim_monitor): Add switch entries for unlink (13),
> +	lseek (14), and stat (15).
> +
>  2021-02-28  Mike Frysinger  <vapier@gentoo.org>
>  
>  	* configure: Regenerate.
> diff --git a/sim/mips/interp.c b/sim/mips/interp.c
> index fd93a12f69a..55b089dbee9 100644
> --- a/sim/mips/interp.c
> +++ b/sim/mips/interp.c
> @@ -50,6 +50,7 @@ code on the hardware.
>  #include "elf-bfd.h"
>  #include "gdb/callback.h"   /* GDB simulator callback interface */
>  #include "gdb/remote-sim.h" /* GDB simulator interface */
> +#include "sim-syscall.h"   /* Simulator system call support */
>  
>  char* pr_addr (SIM_ADDR addr);
>  char* pr_uword64 (uword64 addr);
> @@ -1147,6 +1148,23 @@ Recognized firmware names are: `idt', `pmon', `lsipmon', and `none'.\n",
>    return SIM_RC_OK;
>  }
>  
> +/* stat structures from MIPS32/64.  */
> +static const char stat32_map[] =
> +"st_dev,2:st_ino,2:st_mode,4:st_nlink,2:st_uid,2:st_gid,2"
> +":st_rdev,2:st_size,4:st_atime,4:st_spare1,4:st_mtime,4:st_spare2,4"
> +":st_ctime,4:st_spare3,4:st_blksize,4:st_blocks,4:st_spare4,8";
> +
> +static const char stat64_map[] =
> +"st_dev,2:st_ino,2:st_mode,4:st_nlink,2:st_uid,2:st_gid,2"
> +":st_rdev,2:st_size,8:st_atime,8:st_spare1,8:st_mtime,8:st_spare2,8"
> +":st_ctime,8:st_spare3,8:st_blksize,8:st_blocks,8:st_spare4,16";
> +
> +/* Map for calls using the host struct stat.  */
> +static const CB_TARGET_DEFS_MAP CB_stat_map[] =
> +{
> +  { "stat", CB_SYS_stat, 15 },
> +  { 0, -1, -1 }
> +};
>  
>  
>  /* Simple monitor interface (currently setup for the IDT and PMON monitors) */
> @@ -1167,7 +1185,7 @@ sim_monitor (SIM_DESC sd,
>  
>    /* The following callback functions are available, however the
>       monitor we are simulating does not make use of them: get_errno,
> -     isatty, lseek, rename, system, time and unlink */
> +     isatty, rename, system and time.  */
>    switch (reason)
>      {
>  
> @@ -1241,6 +1259,56 @@ sim_monitor (SIM_DESC sd,
>  	break;
>        }
>  
> +    case 13: /* int unlink(const char *path) */
> +      {
> +	char *path = fetch_str (sd, A0);
> +	V0 = sim_io_unlink (sd, path);
> +	free (path);
> +	break;
> +      }
> +
> +    case 14: /* int lseek(int fd, int offset, int whence) */
> +      {
> +	V0 = sim_io_lseek (sd, A0, A1, A2);
> +	break;
> +      }
> +
> +    case 15: /* int stat(const char *path, struct stat *buf); */
> +      {
> +	/* As long as the infrastructure doesn't cache anything
> +	   related to the stat mapping, this trick gets us a dual
> +	   "struct stat"-type mapping in the least error-prone way.  */
> +	host_callback *cb = STATE_CALLBACK (sd);
> +	const char *saved_map = cb->stat_map;
> +	CB_TARGET_DEFS_MAP *saved_syscall_map = cb->syscall_map;
> +	bfd *prog_bfd = STATE_PROG_BFD (sd);
> +	int is_elf32bit = (elf_elfheader(prog_bfd)->e_ident[EI_CLASS] ==
> +			   ELFCLASS32);
> +	static CB_SYSCALL s;
> +	CB_SYSCALL_INIT (&s);
> +	s.func = 15;
> +	/* Mask out the sign extension part for 64-bit targets because the
> +	   MIPS simulator's memory model is still 32-bit.  */
> +	s.arg1 = A0 & 0xFFFFFFFF;
> +	s.arg2 = A1 & 0xFFFFFFFF;
> +	s.p1 = (PTR) sd;
> +	s.p2 = (PTR) cpu;
> +	s.read_mem = sim_syscall_read_mem;
> +	s.write_mem = sim_syscall_write_mem;
> +
> +	cb->syscall_map = (CB_TARGET_DEFS_MAP *) CB_stat_map;
> +	cb->stat_map = is_elf32bit ? stat32_map : stat64_map;
> +
> +	if (cb_syscall (cb, &s) != CB_RC_OK)
> +	  sim_engine_halt (sd, cpu, NULL, mips_pc_get (cpu),
> +			   sim_stopped, SIM_SIGILL);
> +
> +	V0 = s.result;
> +	cb->stat_map = saved_map;
> +	cb->syscall_map = saved_syscall_map;
> +	break;
> +      }
> +
>      case 17: /* void _exit() */
>        {
>  	sim_io_eprintf (sd, "sim_monitor(17): _exit(int reason) to be coded\n");
> -- 
> 2.25.1
>