[PATCH v4 0/3] target/nios2: semihosting cleanup

[PATCH v4 0/3] target/nios2: semihosting cleanup

[Richard Henderson]

Based-on: <20220607204557.658541-1-richard.henderson@linaro.org>
("[PATCH v4 00/53] semihosting cleanup")

Changes for v4:
  * Split out of v2.
  * Convert host errno to gdb errno, which for nios2 is guest errno.


r~


Richard Henderson (3):
  target/nios2: Eliminate nios2_semi_is_lseek
  target/nios2: Move nios2-semi.c to nios2_softmmu_ss
  target/nios2: Use semihosting/syscalls.h

 target/nios2/nios2-semi.c | 363 ++++++++++----------------------------
 target/nios2/meson.build  |   4 +-
 2 files changed, 91 insertions(+), 276 deletions(-)

-- 
2.34.1

[PATCH v4 1/3] target/nios2: Eliminate nios2_semi_is_lseek

[Richard Henderson]

Reorg nios2_semi_return_* to gdb_syscall_complete_cb.
Use the 32-bit version normally, and the 64-bit version
for HOSTED_LSEEK.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/nios2/nios2-semi.c | 59 +++++++++++++++------------------------
 1 file changed, 23 insertions(+), 36 deletions(-)

diff --git a/target/nios2/nios2-semi.c b/target/nios2/nios2-semi.c
index 4d02789d26..bdf8849689 100644
--- a/target/nios2/nios2-semi.c
+++ b/target/nios2/nios2-semi.c
@@ -108,9 +108,12 @@ static bool translate_stat(CPUNios2State *env, target_ulong addr,
     return true;
 }
 
-static void nios2_semi_return_u32(CPUNios2State *env, uint32_t ret, int err)
+static void nios2_semi_u32_cb(CPUState *cs, uint64_t ret, int err)
 {
+    Nios2CPU *cpu = NIOS2_CPU(cs);
+    CPUNios2State *env = &cpu->env;
     target_ulong args = env->regs[R_ARG1];
+
     if (put_user_u32(ret, args) ||
         put_user_u32(err, args + 4)) {
         /*
@@ -123,9 +126,12 @@ static void nios2_semi_return_u32(CPUNios2State *env, uint32_t ret, int err)
     }
 }
 
-static void nios2_semi_return_u64(CPUNios2State *env, uint64_t ret, int err)
+static void nios2_semi_u64_cb(CPUState *cs, uint64_t ret, int err)
 {
+    Nios2CPU *cpu = NIOS2_CPU(cs);
+    CPUNios2State *env = &cpu->env;
     target_ulong args = env->regs[R_ARG1];
+
     if (put_user_u32(ret >> 32, args) ||
         put_user_u32(ret, args + 4) ||
         put_user_u32(err, args + 8)) {
@@ -135,25 +141,6 @@ static void nios2_semi_return_u64(CPUNios2State *env, uint64_t ret, int err)
     }
 }
 
-static int nios2_semi_is_lseek;
-
-static void nios2_semi_cb(CPUState *cs, uint64_t ret, int err)
-{
-    Nios2CPU *cpu = NIOS2_CPU(cs);
-    CPUNios2State *env = &cpu->env;
-
-    if (nios2_semi_is_lseek) {
-        /*
-         * FIXME: We've already lost the high bits of the lseek
-         * return value.
-         */
-        nios2_semi_return_u64(env, ret, err);
-        nios2_semi_is_lseek = 0;
-    } else {
-        nios2_semi_return_u32(env, ret, err);
-    }
-}
-
 /*
  * Read the input value from the argument block; fail the semihosting
  * call if the memory read fails.
@@ -168,6 +155,7 @@ static void nios2_semi_cb(CPUState *cs, uint64_t ret, int err)
 
 void do_nios2_semihosting(CPUNios2State *env)
 {
+    CPUState *cs = env_cpu(env);
     int nr;
     uint32_t args;
     target_ulong arg0, arg1, arg2, arg3;
@@ -188,7 +176,7 @@ void do_nios2_semihosting(CPUNios2State *env)
         GET_ARG(2);
         GET_ARG(3);
         if (use_gdb_syscalls()) {
-            gdb_do_syscall(nios2_semi_cb, "open,%s,%x,%x", arg0, (int)arg1,
+            gdb_do_syscall(nios2_semi_u32_cb, "open,%s,%x,%x", arg0, (int)arg1,
                            arg2, arg3);
             return;
         } else {
@@ -209,7 +197,7 @@ void do_nios2_semihosting(CPUNios2State *env)
             int fd = arg0;
             if (fd > 2) {
                 if (use_gdb_syscalls()) {
-                    gdb_do_syscall(nios2_semi_cb, "close,%x", arg0);
+                    gdb_do_syscall(nios2_semi_u32_cb, "close,%x", arg0);
                     return;
                 } else {
                     result = close(fd);
@@ -225,7 +213,7 @@ void do_nios2_semihosting(CPUNios2State *env)
         GET_ARG(2);
         len = arg2;
         if (use_gdb_syscalls()) {
-            gdb_do_syscall(nios2_semi_cb, "read,%x,%x,%x",
+            gdb_do_syscall(nios2_semi_u32_cb, "read,%x,%x,%x",
                            arg0, arg1, len);
             return;
         } else {
@@ -245,7 +233,7 @@ void do_nios2_semihosting(CPUNios2State *env)
         GET_ARG(2);
         len = arg2;
         if (use_gdb_syscalls()) {
-            gdb_do_syscall(nios2_semi_cb, "write,%x,%x,%x",
+            gdb_do_syscall(nios2_semi_u32_cb, "write,%x,%x,%x",
                            arg0, arg1, len);
             return;
         } else {
@@ -268,12 +256,11 @@ void do_nios2_semihosting(CPUNios2State *env)
             GET_ARG(3);
             off = (uint32_t)arg2 | ((uint64_t)arg1 << 32);
             if (use_gdb_syscalls()) {
-                nios2_semi_is_lseek = 1;
-                gdb_do_syscall(nios2_semi_cb, "lseek,%x,%lx,%x",
+                gdb_do_syscall(nios2_semi_u64_cb, "lseek,%x,%lx,%x",
                                arg0, off, arg3);
             } else {
                 off = lseek(arg0, off, arg3);
-                nios2_semi_return_u64(env, off, errno);
+                nios2_semi_u64_cb(cs, off, errno);
             }
             return;
         }
@@ -283,7 +270,7 @@ void do_nios2_semihosting(CPUNios2State *env)
         GET_ARG(2);
         GET_ARG(3);
         if (use_gdb_syscalls()) {
-            gdb_do_syscall(nios2_semi_cb, "rename,%s,%s",
+            gdb_do_syscall(nios2_semi_u32_cb, "rename,%s,%s",
                            arg0, (int)arg1, arg2, (int)arg3);
             return;
         } else {
@@ -303,7 +290,7 @@ void do_nios2_semihosting(CPUNios2State *env)
         GET_ARG(0);
         GET_ARG(1);
         if (use_gdb_syscalls()) {
-            gdb_do_syscall(nios2_semi_cb, "unlink,%s",
+            gdb_do_syscall(nios2_semi_u32_cb, "unlink,%s",
                            arg0, (int)arg1);
             return;
         } else {
@@ -322,7 +309,7 @@ void do_nios2_semihosting(CPUNios2State *env)
         GET_ARG(1);
         GET_ARG(2);
         if (use_gdb_syscalls()) {
-            gdb_do_syscall(nios2_semi_cb, "stat,%s,%x",
+            gdb_do_syscall(nios2_semi_u32_cb, "stat,%s,%x",
                            arg0, (int)arg1, arg2);
             return;
         } else {
@@ -345,7 +332,7 @@ void do_nios2_semihosting(CPUNios2State *env)
         GET_ARG(0);
         GET_ARG(1);
         if (use_gdb_syscalls()) {
-            gdb_do_syscall(nios2_semi_cb, "fstat,%x,%x",
+            gdb_do_syscall(nios2_semi_u32_cb, "fstat,%x,%x",
                            arg0, arg1);
             return;
         } else {
@@ -361,7 +348,7 @@ void do_nios2_semihosting(CPUNios2State *env)
         /* Only the tv parameter is used.  tz is assumed NULL.  */
         GET_ARG(0);
         if (use_gdb_syscalls()) {
-            gdb_do_syscall(nios2_semi_cb, "gettimeofday,%x,%x",
+            gdb_do_syscall(nios2_semi_u32_cb, "gettimeofday,%x,%x",
                            arg0, 0);
             return;
         } else {
@@ -382,7 +369,7 @@ void do_nios2_semihosting(CPUNios2State *env)
     case HOSTED_ISATTY:
         GET_ARG(0);
         if (use_gdb_syscalls()) {
-            gdb_do_syscall(nios2_semi_cb, "isatty,%x", arg0);
+            gdb_do_syscall(nios2_semi_u32_cb, "isatty,%x", arg0);
             return;
         } else {
             result = isatty(arg0);
@@ -392,7 +379,7 @@ void do_nios2_semihosting(CPUNios2State *env)
         GET_ARG(0);
         GET_ARG(1);
         if (use_gdb_syscalls()) {
-            gdb_do_syscall(nios2_semi_cb, "system,%s",
+            gdb_do_syscall(nios2_semi_u32_cb, "system,%s",
                            arg0, (int)arg1);
             return;
         } else {
@@ -412,5 +399,5 @@ void do_nios2_semihosting(CPUNios2State *env)
         result = 0;
     }
 failed:
-    nios2_semi_return_u32(env, result, errno);
+    nios2_semi_u32_cb(cs, result, errno);
 }
-- 
2.34.1

Re: [PATCH v4 1/3] target/nios2: Eliminate nios2_semi_is_lseek

[Peter Maydell]

On Wed, 8 Jun 2022 at 03:40, Richard Henderson
<richard.henderson@linaro.org> wrote:
>
> Reorg nios2_semi_return_* to gdb_syscall_complete_cb.
> Use the 32-bit version normally, and the 64-bit version
> for HOSTED_LSEEK.
>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>

thanks
-- PMM

Re: [PATCH v4 1/3] target/nios2: Eliminate nios2_semi_is_lseek

[Philippe Mathieu-Daudé via]

On 8/6/22 04:38, Richard Henderson wrote:
> Reorg nios2_semi_return_* to gdb_syscall_complete_cb.
> Use the 32-bit version normally, and the 64-bit version
> for HOSTED_LSEEK.
> 
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>   target/nios2/nios2-semi.c | 59 +++++++++++++++------------------------
>   1 file changed, 23 insertions(+), 36 deletions(-)

Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>

[PATCH v4 2/3] target/nios2: Move nios2-semi.c to nios2_softmmu_ss

[Richard Henderson]

Semihosting is not enabled for nios2-linux-user.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/nios2/nios2-semi.c | 5 -----
 target/nios2/meson.build  | 4 ++--
 2 files changed, 2 insertions(+), 7 deletions(-)

diff --git a/target/nios2/nios2-semi.c b/target/nios2/nios2-semi.c
index bdf8849689..55061bb2dc 100644
--- a/target/nios2/nios2-semi.c
+++ b/target/nios2/nios2-semi.c
@@ -22,14 +22,9 @@
  */
 
 #include "qemu/osdep.h"
-
 #include "cpu.h"
 #include "exec/gdbstub.h"
-#if defined(CONFIG_USER_ONLY)
-#include "qemu.h"
-#else
 #include "semihosting/softmmu-uaccess.h"
-#endif
 #include "qemu/log.h"
 
 #define HOSTED_EXIT  0
diff --git a/target/nios2/meson.build b/target/nios2/meson.build
index 2bd60ba306..c6e2243cc3 100644
--- a/target/nios2/meson.build
+++ b/target/nios2/meson.build
@@ -1,7 +1,6 @@
 nios2_ss = ss.source_set()
 nios2_ss.add(files(
   'cpu.c',
-  'nios2-semi.c',
   'op_helper.c',
   'translate.c',
 ))
@@ -10,7 +9,8 @@ nios2_softmmu_ss = ss.source_set()
 nios2_softmmu_ss.add(files(
   'helper.c',
   'monitor.c',
-  'mmu.c'
+  'mmu.c',
+  'nios2-semi.c',
 ))
 
 target_arch += {'nios2': nios2_ss}
-- 
2.34.1

Re: [PATCH v4 2/3] target/nios2: Move nios2-semi.c to nios2_softmmu_ss

[Peter Maydell]

On Wed, 8 Jun 2022 at 03:43, Richard Henderson
<richard.henderson@linaro.org> wrote:
>
> Semihosting is not enabled for nios2-linux-user.

True, but maybe it ought to be (in an ideal world)?

Anyway, as far as this patch goes
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>

If we ever add semihosting support to linux-user nios2 it's
easy enough to undo this.

thanks
-- PMM

Re: [PATCH v4 2/3] target/nios2: Move nios2-semi.c to nios2_softmmu_ss

[Richard Henderson]

On 6/9/22 03:36, Peter Maydell wrote:
> On Wed, 8 Jun 2022 at 03:43, Richard Henderson
> <richard.henderson@linaro.org> wrote:
>>
>> Semihosting is not enabled for nios2-linux-user.
> 
> True, but maybe it ought to be (in an ideal world)?

No, I think ideally there'd be no semihosting for user-only.
If you can write to semihosting, you can write to regular syscalls.

Semihosting is good for when we want to do testing of system-mode stuff, and we don't want 
the complication of a full os getting in the way.


r~

Re: [PATCH v4 2/3] target/nios2: Move nios2-semi.c to nios2_softmmu_ss

[Peter Maydell]

On Mon, 20 Jun 2022 at 23:04, Richard Henderson
<richard.henderson@linaro.org> wrote:
>
> On 6/9/22 03:36, Peter Maydell wrote:
> > On Wed, 8 Jun 2022 at 03:43, Richard Henderson
> > <richard.henderson@linaro.org> wrote:
> >>
> >> Semihosting is not enabled for nios2-linux-user.
> >
> > True, but maybe it ought to be (in an ideal world)?
>
> No, I think ideally there'd be no semihosting for user-only.
> If you can write to semihosting, you can write to regular syscalls.

You can, but there are also use cases (notably the gcc test suite)
where people want to run semihosting binaries under usermode.
We can't take away usermode semihosting for those targets where
people are actively using it, so I think it would be more consistent
to support it for usermode for all architectures rather than just
some.

-- PMM

Re: [PATCH v4 2/3] target/nios2: Move nios2-semi.c to nios2_softmmu_ss

[Philippe Mathieu-Daudé via]

On 8/6/22 04:38, Richard Henderson wrote:
> Semihosting is not enabled for nios2-linux-user.
> 
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>   target/nios2/nios2-semi.c | 5 -----
>   target/nios2/meson.build  | 4 ++--
>   2 files changed, 2 insertions(+), 7 deletions(-)

Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>

[PATCH v4 3/3] target/nios2: 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/nios2/nios2-semi.c | 321 +++++++++-----------------------------
 1 file changed, 77 insertions(+), 244 deletions(-)

diff --git a/target/nios2/nios2-semi.c b/target/nios2/nios2-semi.c
index 55061bb2dc..f76e8588c5 100644
--- a/target/nios2/nios2-semi.c
+++ b/target/nios2/nios2-semi.c
@@ -24,6 +24,7 @@
 #include "qemu/osdep.h"
 #include "cpu.h"
 #include "exec/gdbstub.h"
+#include "semihosting/syscalls.h"
 #include "semihosting/softmmu-uaccess.h"
 #include "qemu/log.h"
 
@@ -42,65 +43,33 @@
 #define HOSTED_ISATTY 12
 #define HOSTED_SYSTEM 13
 
-static int translate_openflags(int flags)
+static int host_to_gdb_errno(int err)
 {
-    int hf;
-
-    if (flags & GDB_O_WRONLY) {
-        hf = O_WRONLY;
-    } else if (flags & GDB_O_RDWR) {
-        hf = O_RDWR;
-    } else {
-        hf = O_RDONLY;
+#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;
     }
-
-    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 bool translate_stat(CPUNios2State *env, target_ulong addr,
-                           struct stat *s)
-{
-    struct gdb_stat *p;
-
-    p = lock_user(VERIFY_WRITE, addr, sizeof(struct gdb_stat), 0);
-
-    if (!p) {
-        return false;
-    }
-    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));
-    return true;
+#undef E
 }
 
 static void nios2_semi_u32_cb(CPUState *cs, uint64_t ret, int err)
@@ -110,7 +79,7 @@ static void nios2_semi_u32_cb(CPUState *cs, uint64_t ret, int err)
     target_ulong args = env->regs[R_ARG1];
 
     if (put_user_u32(ret, args) ||
-        put_user_u32(err, args + 4)) {
+        put_user_u32(host_to_gdb_errno(err), args + 4)) {
         /*
          * The nios2 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.
@@ -129,7 +98,7 @@ static void nios2_semi_u64_cb(CPUState *cs, uint64_t ret, int err)
 
     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 nios2 semihosting ABI; just log it */
         qemu_log_mask(LOG_GUEST_ERROR, "nios2-semihosting: return value "
                       "discarded because argument block not writable\n");
@@ -142,22 +111,22 @@ static void nios2_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_nios2_semihosting(CPUNios2State *env)
 {
     CPUState *cs = env_cpu(env);
     int nr;
     uint32_t args;
     target_ulong arg0, arg1, arg2, arg3;
-    void *p;
-    void *q;
-    uint32_t len;
-    uint32_t result;
 
     nr = env->regs[R_ARG0];
     args = env->regs[R_ARG1];
@@ -165,234 +134,98 @@ void do_nios2_semihosting(CPUNios2State *env)
     case HOSTED_EXIT:
         gdb_exit(env->regs[R_ARG0]);
         exit(env->regs[R_ARG0]);
+
     case HOSTED_OPEN:
         GET_ARG(0);
         GET_ARG(1);
         GET_ARG(2);
         GET_ARG(3);
-        if (use_gdb_syscalls()) {
-            gdb_do_syscall(nios2_semi_u32_cb, "open,%s,%x,%x", arg0, (int)arg1,
-                           arg2, arg3);
-            return;
-        } else {
-            p = lock_user_string(arg0);
-            if (!p) {
-                result = -1;
-                errno = EFAULT;
-            } else {
-                result = open(p, translate_openflags(arg2), arg3);
-                unlock_user(p, arg0, 0);
-            }
-        }
+        semihost_sys_open(cs, nios2_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(nios2_semi_u32_cb, "close,%x", arg0);
-                    return;
-                } else {
-                    result = close(fd);
-                }
-            } else {
-                result = 0;
-            }
-            break;
-        }
+        GET_ARG(0);
+        semihost_sys_close(cs, nios2_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(nios2_semi_u32_cb, "read,%x,%x,%x",
-                           arg0, arg1, len);
-            return;
-        } else {
-            p = lock_user(VERIFY_WRITE, arg1, len, 0);
-            if (!p) {
-                result = -1;
-                errno = EFAULT;
-            } else {
-                result = read(arg0, p, len);
-                unlock_user(p, arg1, len);
-            }
-        }
+        semihost_sys_read(cs, nios2_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(nios2_semi_u32_cb, "write,%x,%x,%x",
-                           arg0, arg1, len);
-            return;
-        } else {
-            p = lock_user(VERIFY_READ, arg1, len, 1);
-            if (!p) {
-                result = -1;
-                errno = EFAULT;
-            } else {
-                result = write(arg0, p, len);
-                unlock_user(p, arg0, 0);
-            }
-        }
+        semihost_sys_write(cs, nios2_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(nios2_semi_u64_cb, "lseek,%x,%lx,%x",
-                               arg0, off, arg3);
-            } else {
-                off = lseek(arg0, off, arg3);
-                nios2_semi_u64_cb(cs, off, errno);
-            }
-            return;
-        }
+        GET_ARG64(0);
+        GET_ARG64(1);
+        GET_ARG64(2);
+        GET_ARG64(3);
+        semihost_sys_lseek(cs, nios2_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(nios2_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) {
-                result = -1;
-                errno = EFAULT;
-            } else {
-                result = rename(p, q);
-            }
-            unlock_user(p, arg0, 0);
-            unlock_user(q, arg2, 0);
-        }
+        semihost_sys_rename(cs, nios2_semi_u32_cb, arg0, arg1, arg2, arg3);
         break;
+
     case HOSTED_UNLINK:
         GET_ARG(0);
         GET_ARG(1);
-        if (use_gdb_syscalls()) {
-            gdb_do_syscall(nios2_semi_u32_cb, "unlink,%s",
-                           arg0, (int)arg1);
-            return;
-        } else {
-            p = lock_user_string(arg0);
-            if (!p) {
-                result = -1;
-                errno = EFAULT;
-            } else {
-                result = unlink(p);
-                unlock_user(p, arg0, 0);
-            }
-        }
+        semihost_sys_remove(cs, nios2_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(nios2_semi_u32_cb, "stat,%s,%x",
-                           arg0, (int)arg1, arg2);
-            return;
-        } else {
-            struct stat s;
-            p = lock_user_string(arg0);
-            if (!p) {
-                result = -1;
-                errno = EFAULT;
-            } else {
-                result = stat(p, &s);
-                unlock_user(p, arg0, 0);
-            }
-            if (result == 0 && !translate_stat(env, arg2, &s)) {
-                result = -1;
-                errno = EFAULT;
-            }
-        }
+        semihost_sys_stat(cs, nios2_semi_u32_cb, arg0, arg1, arg2);
         break;
+
     case HOSTED_FSTAT:
         GET_ARG(0);
         GET_ARG(1);
-        if (use_gdb_syscalls()) {
-            gdb_do_syscall(nios2_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)) {
-                result = -1;
-                errno = EFAULT;
-            }
-        }
+        semihost_sys_fstat(cs, nios2_semi_u32_cb, arg0, arg1);
         break;
+
     case HOSTED_GETTIMEOFDAY:
-        /* Only the tv parameter is used.  tz is assumed NULL.  */
         GET_ARG(0);
-        if (use_gdb_syscalls()) {
-            gdb_do_syscall(nios2_semi_u32_cb, "gettimeofday,%x,%x",
-                           arg0, 0);
-            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) {
-                result = -1;
-                errno = EFAULT;
-            } 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));
-            }
-        }
+        GET_ARG(1);
+        semihost_sys_gettimeofday(cs, nios2_semi_u32_cb, arg0, arg1);
         break;
+
     case HOSTED_ISATTY:
         GET_ARG(0);
-        if (use_gdb_syscalls()) {
-            gdb_do_syscall(nios2_semi_u32_cb, "isatty,%x", arg0);
-            return;
-        } else {
-            result = isatty(arg0);
-        }
+        semihost_sys_isatty(cs, nios2_semi_u32_cb, arg0);
         break;
+
     case HOSTED_SYSTEM:
         GET_ARG(0);
         GET_ARG(1);
-        if (use_gdb_syscalls()) {
-            gdb_do_syscall(nios2_semi_u32_cb, "system,%s",
-                           arg0, (int)arg1);
-            return;
-        } else {
-            p = lock_user_string(arg0);
-            if (!p) {
-                result = -1;
-                errno = EFAULT;
-            } else {
-                result = system(p);
-                unlock_user(p, arg0, 0);
-            }
-        }
+        semihost_sys_system(cs, nios2_semi_u32_cb, arg0, arg1);
         break;
+
     default:
         qemu_log_mask(LOG_GUEST_ERROR, "nios2-semihosting: unsupported "
                       "semihosting syscall %d\n", nr);
-        result = 0;
+        nios2_semi_u32_cb(cs, -1, ENOSYS);
+        break;
+
+    failed:
+        nios2_semi_u32_cb(cs, -1, EFAULT);
+        break;
+    failed64:
+        nios2_semi_u64_cb(cs, -1, EFAULT);
+        break;
     }
-failed:
-    nios2_semi_u32_cb(cs, result, errno);
 }
-- 
2.34.1

Re: [PATCH v4 3/3] target/nios2: Use semihosting/syscalls.h

[Peter Maydell]

On Wed, 8 Jun 2022 at 03:41, Richard Henderson
<richard.henderson@linaro.org> wrote:
>
> 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>

The commit message presents this as just a no-behaviour-change
refactoring but it looks like the patch includes changes to
the errno semantics ?

thanks
-- PMM