target/mips: Remove tswap() calls in semihosting uhi_fstat_cb()

Commit Message

Philippe Mathieu-Daudé Dec. 5, 2024, 11:13 p.m. UTC

In preparation of heterogeneous emulation where cores with
different endianness can run concurrently, we need to remove
the tswap() calls -- which use a fixed per-binary endianness.

Get the endianness of the UHI CPU accessed using
mips_env_is_bigendian() and replace the tswap() calls
by bswap() ones when necessary.

Signed-off-by: Philippe Mathieu-Daudé <[e-mail]>
---
 target/mips/tcg/sysemu/mips-semi.c | 43 +++++++++++++++++++++---------
 1 file changed, 30 insertions(+), 13 deletions(-)

Comments

Richard Henderson Dec. 6, 2024, 1:09 a.m. UTC | #1

On 12/5/24 17:13, Philippe Mathieu-Daudé wrote:
> In preparation of heterogeneous emulation where cores with
> different endianness can run concurrently, we need to remove
> the tswap() calls -- which use a fixed per-binary endianness.
> 
> Get the endianness of the UHI CPU accessed using
> mips_env_is_bigendian() and replace the tswap() calls
> by bswap() ones when necessary.
> 
> Signed-off-by: Philippe Mathieu-Daudé <[e-mail]>
> ---
>   target/mips/tcg/sysemu/mips-semi.c | 43 +++++++++++++++++++++---------
>   1 file changed, 30 insertions(+), 13 deletions(-)

Reviewed-by: Richard Henderson <[e-mail]>

> +            bswap16s((uint16_t *)&dst->uhi_st_dev);

Rather than cast, maybe better to

     dst->uhi_st_dev = bswap16(dst->uhi_st_dev);


r~

Patch

diff --git a/target/mips/tcg/sysemu/mips-semi.c b/target/mips/tcg/sysemu/mips-semi.c
index 5ba06e95734..66a0de6b700 100644
--- a/target/mips/tcg/sysemu/mips-semi.c
+++ b/target/mips/tcg/sysemu/mips-semi.c
@@ -168,6 +168,7 @@  static void uhi_fstat_cb(CPUState *cs, uint64_t ret, int err)
 
     if (!err) {
         CPUMIPSState *env = cpu_env(cs);
+        bool swap_needed = HOST_BIG_ENDIAN != mips_env_is_bigendian(env);
         target_ulong addr = env->active_tc.gpr[5];
         UHIStat *dst = lock_user(VERIFY_WRITE, addr, sizeof(UHIStat), 1);
         struct gdb_stat s;
@@ -179,19 +180,35 @@  static void uhi_fstat_cb(CPUState *cs, uint64_t ret, int err)
         memcpy(&s, dst, sizeof(struct gdb_stat));
         memset(dst, 0, sizeof(UHIStat));
 
-        dst->uhi_st_dev = tswap16(be32_to_cpu(s.gdb_st_dev));
-        dst->uhi_st_ino = tswap16(be32_to_cpu(s.gdb_st_ino));
-        dst->uhi_st_mode = tswap32(be32_to_cpu(s.gdb_st_mode));
-        dst->uhi_st_nlink = tswap16(be32_to_cpu(s.gdb_st_nlink));
-        dst->uhi_st_uid = tswap16(be32_to_cpu(s.gdb_st_uid));
-        dst->uhi_st_gid = tswap16(be32_to_cpu(s.gdb_st_gid));
-        dst->uhi_st_rdev = tswap16(be32_to_cpu(s.gdb_st_rdev));
-        dst->uhi_st_size = tswap64(be64_to_cpu(s.gdb_st_size));
-        dst->uhi_st_atime = tswap64(be32_to_cpu(s.gdb_st_atime));
-        dst->uhi_st_mtime = tswap64(be32_to_cpu(s.gdb_st_mtime));
-        dst->uhi_st_ctime = tswap64(be32_to_cpu(s.gdb_st_ctime));
-        dst->uhi_st_blksize = tswap64(be64_to_cpu(s.gdb_st_blksize));
-        dst->uhi_st_blocks = tswap64(be64_to_cpu(s.gdb_st_blocks));
+        dst->uhi_st_dev = be32_to_cpu(s.gdb_st_dev);
+        dst->uhi_st_ino = be32_to_cpu(s.gdb_st_ino);
+        dst->uhi_st_mode = be32_to_cpu(s.gdb_st_mode);
+        dst->uhi_st_nlink = be32_to_cpu(s.gdb_st_nlink);
+        dst->uhi_st_uid = be32_to_cpu(s.gdb_st_uid);
+        dst->uhi_st_gid = be32_to_cpu(s.gdb_st_gid);
+        dst->uhi_st_rdev = be32_to_cpu(s.gdb_st_rdev);
+        dst->uhi_st_size = be64_to_cpu(s.gdb_st_size);
+        dst->uhi_st_atime = be32_to_cpu(s.gdb_st_atime);
+        dst->uhi_st_mtime = be32_to_cpu(s.gdb_st_mtime);
+        dst->uhi_st_ctime = be32_to_cpu(s.gdb_st_ctime);
+        dst->uhi_st_blksize = be64_to_cpu(s.gdb_st_blksize);
+        dst->uhi_st_blocks = be64_to_cpu(s.gdb_st_blocks);
+
+        if (swap_needed) {
+            bswap16s((uint16_t *)&dst->uhi_st_dev);
+            bswap16s(&dst->uhi_st_ino);
+            bswap32s(&dst->uhi_st_mode);
+            bswap16s(&dst->uhi_st_nlink);
+            bswap16s(&dst->uhi_st_uid);
+            bswap16s(&dst->uhi_st_gid);
+            bswap16s((uint16_t *)&dst->uhi_st_rdev);
+            bswap64s(&dst->uhi_st_size);
+            bswap64s(&dst->uhi_st_atime);
+            bswap64s(&dst->uhi_st_mtime);
+            bswap64s(&dst->uhi_st_ctime);
+            bswap64s(&dst->uhi_st_blksize);
+            bswap64s(&dst->uhi_st_blocks);
+        }
 
         unlock_user(dst, addr, sizeof(UHIStat));
     }