[PATCH v5 0/2] target/m68k: semihosting cleanup

[PATCH v5 0/2] target/m68k: semihosting cleanup

[Richard Henderson]

Changes for v5:
  * Rebase on master, which includes all prereq and patch 1.
  * Split out errno remapping to a separate patch.

r~

Richard Henderson (2):
  target/m68k: Use semihosting/syscalls.h
  target/m68k: Convert semihosting errno to gdb remote errno

 target/m68k/m68k-semi.c | 306 ++++++++++------------------------------
 1 file changed, 76 insertions(+), 230 deletions(-)

-- 
2.34.1

[PATCH v5 1/2] target/m68k: Use semihosting/syscalls.h

[Richard Henderson]

This separates guest file descriptors from host file descriptors,
and utilizes shared infrastructure for integration with gdbstub.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/m68k/m68k-semi.c | 281 +++++++---------------------------------
 1 file changed, 49 insertions(+), 232 deletions(-)

diff --git a/target/m68k/m68k-semi.c b/target/m68k/m68k-semi.c
index d0697ddbd1..586a801034 100644
--- a/target/m68k/m68k-semi.c
+++ b/target/m68k/m68k-semi.c
@@ -21,6 +21,7 @@
 
 #include "cpu.h"
 #include "exec/gdbstub.h"
+#include "semihosting/syscalls.h"
 #include "semihosting/softmmu-uaccess.h"
 #include "hw/boards.h"
 #include "qemu/log.h"
@@ -40,56 +41,6 @@
 #define HOSTED_ISATTY 12
 #define HOSTED_SYSTEM 13
 
-static int translate_openflags(int flags)
-{
-    int hf;
-
-    if (flags & GDB_O_WRONLY)
-        hf = O_WRONLY;
-    else if (flags & GDB_O_RDWR)
-        hf = O_RDWR;
-    else
-        hf = O_RDONLY;
-
-    if (flags & GDB_O_APPEND) hf |= O_APPEND;
-    if (flags & GDB_O_CREAT) hf |= O_CREAT;
-    if (flags & GDB_O_TRUNC) hf |= O_TRUNC;
-    if (flags & GDB_O_EXCL) hf |= O_EXCL;
-
-    return hf;
-}
-
-static void translate_stat(CPUM68KState *env, target_ulong addr, struct stat *s)
-{
-    struct gdb_stat *p;
-
-    p = lock_user(VERIFY_WRITE, addr, sizeof(struct gdb_stat), 0);
-    if (!p) {
-        /* FIXME - should this return an error code? */
-        return;
-    }
-    p->gdb_st_dev = cpu_to_be32(s->st_dev);
-    p->gdb_st_ino = cpu_to_be32(s->st_ino);
-    p->gdb_st_mode = cpu_to_be32(s->st_mode);
-    p->gdb_st_nlink = cpu_to_be32(s->st_nlink);
-    p->gdb_st_uid = cpu_to_be32(s->st_uid);
-    p->gdb_st_gid = cpu_to_be32(s->st_gid);
-    p->gdb_st_rdev = cpu_to_be32(s->st_rdev);
-    p->gdb_st_size = cpu_to_be64(s->st_size);
-#ifdef _WIN32
-    /* Windows stat is missing some fields.  */
-    p->gdb_st_blksize = 0;
-    p->gdb_st_blocks = 0;
-#else
-    p->gdb_st_blksize = cpu_to_be64(s->st_blksize);
-    p->gdb_st_blocks = cpu_to_be64(s->st_blocks);
-#endif
-    p->gdb_st_atime = cpu_to_be32(s->st_atime);
-    p->gdb_st_mtime = cpu_to_be32(s->st_mtime);
-    p->gdb_st_ctime = cpu_to_be32(s->st_ctime);
-    unlock_user(p, addr, sizeof(struct gdb_stat));
-}
-
 static void m68k_semi_u32_cb(CPUState *cs, uint64_t ret, int err)
 {
     M68kCPU *cpu = M68K_CPU(cs);
@@ -129,248 +80,109 @@ static void m68k_semi_u64_cb(CPUState *cs, uint64_t ret, int err)
  */
 #define GET_ARG(n) do {                                 \
     if (get_user_ual(arg ## n, args + (n) * 4)) {       \
-        result = -1;                                    \
-        errno = EFAULT;                                 \
         goto failed;                                    \
     }                                                   \
 } while (0)
 
+#define GET_ARG64(n) do {                               \
+    if (get_user_ual(arg ## n, args + (n) * 4)) {       \
+        goto failed64;                                  \
+    }                                                   \
+} while (0)
+
+
 void do_m68k_semihosting(CPUM68KState *env, int nr)
 {
     CPUState *cs = env_cpu(env);
     uint32_t args;
     target_ulong arg0, arg1, arg2, arg3;
-    void *p;
-    void *q;
-    uint32_t len;
-    uint32_t result;
 
     args = env->dregs[1];
     switch (nr) {
     case HOSTED_EXIT:
         gdb_exit(env->dregs[0]);
         exit(env->dregs[0]);
+
     case HOSTED_OPEN:
         GET_ARG(0);
         GET_ARG(1);
         GET_ARG(2);
         GET_ARG(3);
-        if (use_gdb_syscalls()) {
-            gdb_do_syscall(m68k_semi_u32_cb, "open,%s,%x,%x", arg0, (int)arg1,
-                           arg2, arg3);
-            return;
-        } else {
-            p = lock_user_string(arg0);
-            if (!p) {
-                /* FIXME - check error code? */
-                result = -1;
-            } else {
-                result = open(p, translate_openflags(arg2), arg3);
-                unlock_user(p, arg0, 0);
-            }
-        }
+        semihost_sys_open(cs, m68k_semi_u32_cb, arg0, arg1, arg2, arg3);
         break;
+
     case HOSTED_CLOSE:
-        {
-            /* Ignore attempts to close stdin/out/err.  */
-            GET_ARG(0);
-            int fd = arg0;
-            if (fd > 2) {
-                if (use_gdb_syscalls()) {
-                    gdb_do_syscall(m68k_semi_u32_cb, "close,%x", arg0);
-                    return;
-                } else {
-                    result = close(fd);
-                }
-            } else {
-                result = 0;
-            }
-            break;
-        }
+        GET_ARG(0);
+        semihost_sys_close(cs, m68k_semi_u32_cb, arg0);
+        break;
+
     case HOSTED_READ:
         GET_ARG(0);
         GET_ARG(1);
         GET_ARG(2);
-        len = arg2;
-        if (use_gdb_syscalls()) {
-            gdb_do_syscall(m68k_semi_u32_cb, "read,%x,%x,%x",
-                           arg0, arg1, len);
-            return;
-        } else {
-            p = lock_user(VERIFY_WRITE, arg1, len, 0);
-            if (!p) {
-                /* FIXME - check error code? */
-                result = -1;
-            } else {
-                result = read(arg0, p, len);
-                unlock_user(p, arg1, len);
-            }
-        }
+        semihost_sys_read(cs, m68k_semi_u32_cb, arg0, arg1, arg2);
         break;
+
     case HOSTED_WRITE:
         GET_ARG(0);
         GET_ARG(1);
         GET_ARG(2);
-        len = arg2;
-        if (use_gdb_syscalls()) {
-            gdb_do_syscall(m68k_semi_u32_cb, "write,%x,%x,%x",
-                           arg0, arg1, len);
-            return;
-        } else {
-            p = lock_user(VERIFY_READ, arg1, len, 1);
-            if (!p) {
-                /* FIXME - check error code? */
-                result = -1;
-            } else {
-                result = write(arg0, p, len);
-                unlock_user(p, arg0, 0);
-            }
-        }
+        semihost_sys_write(cs, m68k_semi_u32_cb, arg0, arg1, arg2);
         break;
+
     case HOSTED_LSEEK:
-        {
-            uint64_t off;
-            GET_ARG(0);
-            GET_ARG(1);
-            GET_ARG(2);
-            GET_ARG(3);
-            off = (uint32_t)arg2 | ((uint64_t)arg1 << 32);
-            if (use_gdb_syscalls()) {
-                gdb_do_syscall(m68k_semi_u64_cb, "fseek,%x,%lx,%x",
-                               arg0, off, arg3);
-            } else {
-                off = lseek(arg0, off, arg3);
-                m68k_semi_u64_cb(cs, off, errno);
-            }
-            return;
-        }
+        GET_ARG64(0);
+        GET_ARG64(1);
+        GET_ARG64(2);
+        GET_ARG64(3);
+        semihost_sys_lseek(cs, m68k_semi_u64_cb, arg0,
+                           deposit64(arg2, arg1, 32, 32), arg3);
+        break;
+
     case HOSTED_RENAME:
         GET_ARG(0);
         GET_ARG(1);
         GET_ARG(2);
         GET_ARG(3);
-        if (use_gdb_syscalls()) {
-            gdb_do_syscall(m68k_semi_u32_cb, "rename,%s,%s",
-                           arg0, (int)arg1, arg2, (int)arg3);
-            return;
-        } else {
-            p = lock_user_string(arg0);
-            q = lock_user_string(arg2);
-            if (!p || !q) {
-                /* FIXME - check error code? */
-                result = -1;
-            } else {
-                result = rename(p, q);
-            }
-            unlock_user(p, arg0, 0);
-            unlock_user(q, arg2, 0);
-        }
+        semihost_sys_rename(cs, m68k_semi_u32_cb, arg0, arg1, arg2, arg3);
         break;
+
     case HOSTED_UNLINK:
         GET_ARG(0);
         GET_ARG(1);
-        if (use_gdb_syscalls()) {
-            gdb_do_syscall(m68k_semi_u32_cb, "unlink,%s",
-                           arg0, (int)arg1);
-            return;
-        } else {
-            p = lock_user_string(arg0);
-            if (!p) {
-                /* FIXME - check error code? */
-                result = -1;
-            } else {
-                result = unlink(p);
-                unlock_user(p, arg0, 0);
-            }
-        }
+        semihost_sys_remove(cs, m68k_semi_u32_cb, arg0, arg1);
         break;
+
     case HOSTED_STAT:
         GET_ARG(0);
         GET_ARG(1);
         GET_ARG(2);
-        if (use_gdb_syscalls()) {
-            gdb_do_syscall(m68k_semi_u32_cb, "stat,%s,%x",
-                           arg0, (int)arg1, arg2);
-            return;
-        } else {
-            struct stat s;
-            p = lock_user_string(arg0);
-            if (!p) {
-                /* FIXME - check error code? */
-                result = -1;
-            } else {
-                result = stat(p, &s);
-                unlock_user(p, arg0, 0);
-            }
-            if (result == 0) {
-                translate_stat(env, arg2, &s);
-            }
-        }
+        semihost_sys_stat(cs, m68k_semi_u32_cb, arg0, arg1, arg2);
         break;
+
     case HOSTED_FSTAT:
         GET_ARG(0);
         GET_ARG(1);
-        if (use_gdb_syscalls()) {
-            gdb_do_syscall(m68k_semi_u32_cb, "fstat,%x,%x",
-                           arg0, arg1);
-            return;
-        } else {
-            struct stat s;
-            result = fstat(arg0, &s);
-            if (result == 0) {
-                translate_stat(env, arg1, &s);
-            }
-        }
+        semihost_sys_fstat(cs, m68k_semi_u32_cb, arg0, arg1);
         break;
+
     case HOSTED_GETTIMEOFDAY:
         GET_ARG(0);
         GET_ARG(1);
-        if (use_gdb_syscalls()) {
-            gdb_do_syscall(m68k_semi_u32_cb, "gettimeofday,%x,%x",
-                           arg0, arg1);
-            return;
-        } else {
-            struct gdb_timeval *p;
-            int64_t rt = g_get_real_time();
-            p = lock_user(VERIFY_WRITE, arg0, sizeof(struct gdb_timeval), 0);
-            if (!p) {
-                /* FIXME - check error code? */
-                result = -1;
-            } else {
-                result = 0;
-                p->tv_sec = cpu_to_be32(rt / G_USEC_PER_SEC);
-                p->tv_usec = cpu_to_be64(rt % G_USEC_PER_SEC);
-                unlock_user(p, arg0, sizeof(struct gdb_timeval));
-            }
-        }
+        semihost_sys_gettimeofday(cs, m68k_semi_u32_cb, arg0, arg1);
         break;
+
     case HOSTED_ISATTY:
         GET_ARG(0);
-        if (use_gdb_syscalls()) {
-            gdb_do_syscall(m68k_semi_u32_cb, "isatty,%x", arg0);
-            return;
-        } else {
-            result = isatty(arg0);
-        }
+        semihost_sys_isatty(cs, m68k_semi_u32_cb, arg0);
         break;
+
     case HOSTED_SYSTEM:
         GET_ARG(0);
         GET_ARG(1);
-        if (use_gdb_syscalls()) {
-            gdb_do_syscall(m68k_semi_u32_cb, "system,%s",
-                           arg0, (int)arg1);
-            return;
-        } else {
-            p = lock_user_string(arg0);
-            if (!p) {
-                /* FIXME - check error code? */
-                result = -1;
-            } else {
-                result = system(p);
-                unlock_user(p, arg0, 0);
-            }
-        }
+        semihost_sys_system(cs, m68k_semi_u32_cb, arg0, arg1);
         break;
+
     case HOSTED_INIT_SIM:
         /*
          * FIXME: This is wrong for boards where RAM does not start at
@@ -379,10 +191,15 @@ void do_m68k_semihosting(CPUM68KState *env, int nr)
         env->dregs[1] = current_machine->ram_size;
         env->aregs[7] = current_machine->ram_size;
         return;
+
     default:
         cpu_abort(env_cpu(env), "Unsupported semihosting syscall %d\n", nr);
-        result = 0;
+
+    failed:
+        m68k_semi_u32_cb(cs, -1, EFAULT);
+        break;
+    failed64:
+        m68k_semi_u64_cb(cs, -1, EFAULT);
+        break;
     }
-failed:
-    m68k_semi_u32_cb(cs, result, errno);
 }
-- 
2.34.1

Re: [PATCH v5 1/2] target/m68k: Use semihosting/syscalls.h

[Laurent Vivier]

Le 28/06/2022 à 13:00, Richard Henderson a écrit :
> This separates guest file descriptors from host file descriptors,
> and utilizes shared infrastructure for integration with gdbstub.
> 
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>   target/m68k/m68k-semi.c | 281 +++++++---------------------------------
>   1 file changed, 49 insertions(+), 232 deletions(-)

Acked-by: Laurent Vivier <laurent@vivier.eu>

[PATCH v5 2/2] target/m68k: Convert semihosting errno to gdb remote errno

[Richard Henderson]

The semihosting abi used by m68k uses the gdb remote
protocol filesys errnos.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/m68k/m68k-semi.c | 33 +++++++++++++++++++++++++++++++--
 1 file changed, 31 insertions(+), 2 deletions(-)

diff --git a/target/m68k/m68k-semi.c b/target/m68k/m68k-semi.c
index 586a801034..87b1314925 100644
--- a/target/m68k/m68k-semi.c
+++ b/target/m68k/m68k-semi.c
@@ -41,6 +41,35 @@
 #define HOSTED_ISATTY 12
 #define HOSTED_SYSTEM 13
 
+static int host_to_gdb_errno(int err)
+{
+#define E(X)  case E##X: return GDB_E##X
+    switch (err) {
+    E(PERM);
+    E(NOENT);
+    E(INTR);
+    E(BADF);
+    E(ACCES);
+    E(FAULT);
+    E(BUSY);
+    E(EXIST);
+    E(NODEV);
+    E(NOTDIR);
+    E(ISDIR);
+    E(INVAL);
+    E(NFILE);
+    E(MFILE);
+    E(FBIG);
+    E(NOSPC);
+    E(SPIPE);
+    E(ROFS);
+    E(NAMETOOLONG);
+    default:
+        return GDB_EUNKNOWN;
+    }
+#undef E
+}
+
 static void m68k_semi_u32_cb(CPUState *cs, uint64_t ret, int err)
 {
     M68kCPU *cpu = M68K_CPU(cs);
@@ -48,7 +77,7 @@ static void m68k_semi_u32_cb(CPUState *cs, uint64_t ret, int err)
 
     target_ulong args = env->dregs[1];
     if (put_user_u32(ret, args) ||
-        put_user_u32(err, args + 4)) {
+        put_user_u32(host_to_gdb_errno(err), args + 4)) {
         /*
          * The m68k semihosting ABI does not provide any way to report this
          * error to the guest, so the best we can do is log it in qemu.
@@ -67,7 +96,7 @@ static void m68k_semi_u64_cb(CPUState *cs, uint64_t ret, int err)
     target_ulong args = env->dregs[1];
     if (put_user_u32(ret >> 32, args) ||
         put_user_u32(ret, args + 4) ||
-        put_user_u32(err, args + 8)) {
+        put_user_u32(host_to_gdb_errno(err), args + 8)) {
         /* No way to report this via m68k semihosting ABI; just log it */
         qemu_log_mask(LOG_GUEST_ERROR, "m68k-semihosting: return value "
                       "discarded because argument block not writable\n");
-- 
2.34.1

Re: [PATCH v5 2/2] target/m68k: Convert semihosting errno to gdb remote errno

[Laurent Vivier]

Le 28/06/2022 à 13:00, Richard Henderson a écrit :
> The semihosting abi used by m68k uses the gdb remote
> protocol filesys errnos.
> 
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>   target/m68k/m68k-semi.c | 33 +++++++++++++++++++++++++++++++--
>   1 file changed, 31 insertions(+), 2 deletions(-)

Acked-by: Laurent Vivier <laurent@vivier.eu>