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[PATCH v2 47/74] semihosting: Create semihost_sys_poll_one
From: |
Richard Henderson |
Subject: |
[PATCH v2 47/74] semihosting: Create semihost_sys_poll_one |
Date: |
Tue, 3 May 2022 12:48:16 -0700 |
This will be used for implementing the xtensa select_one
system call. Choose "poll" over "select" so that we can
reuse Glib's g_poll constants and to avoid struct timeval.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
include/semihosting/console.h | 16 ++++++++
include/semihosting/syscalls.h | 3 ++
semihosting/console.c | 19 ++++++++-
semihosting/syscalls.c | 70 ++++++++++++++++++++++++++++++++++
4 files changed, 106 insertions(+), 2 deletions(-)
diff --git a/include/semihosting/console.h b/include/semihosting/console.h
index 20c31d89d4..61b0cb3a94 100644
--- a/include/semihosting/console.h
+++ b/include/semihosting/console.h
@@ -53,4 +53,20 @@ int qemu_semihosting_console_write(void *buf, int len);
*/
int qemu_semihosting_log_out(const char *s, int len);
+/*
+ * qemu_semihosting_console_block_until_ready:
+ * @cs: CPUState
+ *
+ * If no data is available we suspend the CPU and will re-execute the
+ * instruction when data is available.
+ */
+void qemu_semihosting_console_block_until_ready(CPUState *cs);
+
+/**
+ * qemu_semihosting_console_ready:
+ *
+ * Return true if characters are available for read; does not block.
+ */
+bool qemu_semihosting_console_ready(void);
+
#endif /* SEMIHOST_CONSOLE_H */
diff --git a/include/semihosting/syscalls.h b/include/semihosting/syscalls.h
index 347200cb9f..3a5ec229eb 100644
--- a/include/semihosting/syscalls.h
+++ b/include/semihosting/syscalls.h
@@ -69,4 +69,7 @@ void semihost_sys_system(CPUState *cs,
gdb_syscall_complete_cb complete,
void semihost_sys_gettimeofday(CPUState *cs, gdb_syscall_complete_cb complete,
target_ulong tv_addr, target_ulong tz_addr);
+void semihost_sys_poll_one(CPUState *cs, gdb_syscall_complete_cb complete,
+ int fd, GIOCondition cond, int timeout);
+
#endif /* SEMIHOSTING_SYSCALLS_H */
diff --git a/semihosting/console.c b/semihosting/console.c
index c84ab97ab6..cda7cf1905 100644
--- a/semihosting/console.c
+++ b/semihosting/console.c
@@ -77,10 +77,17 @@ static void console_read(void *opaque, const uint8_t *buf,
int size)
c->sleeping_cpus = NULL;
}
-int qemu_semihosting_console_read(CPUState *cs, void *buf, int len)
+bool qemu_semihosting_console_ready(void)
+{
+ SemihostingConsole *c = &console;
+
+ g_assert(qemu_mutex_iothread_locked());
+ return !fifo8_is_empty(&c->fifo);
+}
+
+void qemu_semihosting_console_block_until_ready(CPUState *cs)
{
SemihostingConsole *c = &console;
- int ret = 0;
g_assert(qemu_mutex_iothread_locked());
@@ -92,6 +99,14 @@ int qemu_semihosting_console_read(CPUState *cs, void *buf,
int len)
cpu_loop_exit(cs);
/* never returns */
}
+}
+
+int qemu_semihosting_console_read(CPUState *cs, void *buf, int len)
+{
+ SemihostingConsole *c = &console;
+ int ret = 0;
+
+ qemu_semihosting_console_block_until_ready(cs);
/* Read until buffer full or fifo exhausted. */
do {
diff --git a/semihosting/syscalls.c b/semihosting/syscalls.c
index aa4ee47649..1b87c37437 100644
--- a/semihosting/syscalls.c
+++ b/semihosting/syscalls.c
@@ -550,6 +550,21 @@ static void host_gettimeofday(CPUState *cs,
gdb_syscall_complete_cb complete,
unlock_user(p, tv_addr, sizeof(struct gdb_timeval));
}
+#ifndef CONFIG_USER_ONLY
+static void host_poll_one(CPUState *cs, gdb_syscall_complete_cb complete,
+ GuestFD *gf, GIOCondition cond, int timeout)
+{
+ /*
+ * Since this is only used by xtensa in system mode, and stdio is
+ * handled through GuestFDConsole, and there are no semihosting
+ * system calls for sockets and the like, that means this descriptor
+ * must be a normal file. Normal files never block and are thus
+ * always ready.
+ */
+ complete(cs, cond & (G_IO_IN | G_IO_OUT), 0);
+}
+#endif
+
/*
* Static file semihosting syscall implementations.
*/
@@ -658,6 +673,34 @@ static void console_fstat(CPUState *cs,
gdb_syscall_complete_cb complete,
complete(cs, ret ? -1 : 0, ret ? -ret : 0);
}
+#ifndef CONFIG_USER_ONLY
+static void console_poll_one(CPUState *cs, gdb_syscall_complete_cb complete,
+ GuestFD *gf, GIOCondition cond, int timeout)
+{
+ /* The semihosting console does not support urgent data or errors. */
+ cond &= G_IO_IN | G_IO_OUT;
+
+ /*
+ * Since qemu_semihosting_console_write never blocks, we can
+ * consider output always ready -- leave G_IO_OUT alone.
+ * All that remains is to conditionally signal input ready.
+ * Since output ready causes an immediate return, only block
+ * for G_IO_IN alone.
+ *
+ * TODO: Implement proper timeout. For now, only support
+ * indefinite wait or immediate poll.
+ */
+ if (cond == G_IO_IN && timeout < 0) {
+ qemu_semihosting_console_block_until_ready(cs);
+ /* We returned -- input must be ready. */
+ } else if ((cond & G_IO_IN) && !qemu_semihosting_console_ready()) {
+ cond &= ~G_IO_IN;
+ }
+
+ complete(cs, cond, 0);
+}
+#endif
+
/*
* Syscall entry points.
*/
@@ -936,3 +979,30 @@ void semihost_sys_gettimeofday(CPUState *cs,
gdb_syscall_complete_cb complete,
host_gettimeofday(cs, complete, tv_addr, tz_addr);
}
}
+
+#ifndef CONFIG_USER_ONLY
+void semihost_sys_poll_one(CPUState *cs, gdb_syscall_complete_cb complete,
+ int fd, GIOCondition cond, int timeout)
+{
+ GuestFD *gf = get_guestfd(fd);
+
+ if (!gf) {
+ complete(cs, G_IO_NVAL, 1);
+ return;
+ }
+ switch (gf->type) {
+ case GuestFDGDB:
+ complete(cs, G_IO_NVAL, 1);
+ break;
+ case GuestFDHost:
+ host_poll_one(cs, complete, gf, cond, timeout);
+ break;
+ case GuestFDConsole:
+ console_poll_one(cs, complete, gf, cond, timeout);
+ break;
+ case GuestFDStatic:
+ default:
+ g_assert_not_reached();
+ }
+}
+#endif
--
2.34.1
- [PATCH v2 38/74] semihosting: Cleanup chardev init, (continued)
- [PATCH v2 38/74] semihosting: Cleanup chardev init, Richard Henderson, 2022/05/03
- [PATCH v2 37/74] semihosting: Expand qemu_semihosting_console_inc to read, Richard Henderson, 2022/05/03
- [PATCH v2 36/74] semihosting: Pass CPUState to qemu_semihosting_console_inc, Richard Henderson, 2022/05/03
- [PATCH v2 39/74] semihosting: Create qemu_semihosting_console_write, Richard Henderson, 2022/05/03
- [PATCH v2 40/74] semihosting: Add GuestFDConsole, Richard Henderson, 2022/05/03
- [PATCH v2 41/74] semihosting: Create qemu_semihosting_guestfd_init, Richard Henderson, 2022/05/03
- [PATCH v2 42/74] semihosting: Use console_in_gf for SYS_READC, Richard Henderson, 2022/05/03
- [PATCH v2 46/74] semihosting: Remove qemu_semihosting_console_outs, Richard Henderson, 2022/05/03
- [PATCH v2 43/74] semihosting: Use console_out_gf for SYS_WRITEC, Richard Henderson, 2022/05/03
- [PATCH v2 44/74] semihosting: Remove qemu_semihosting_console_outc, Richard Henderson, 2022/05/03
- [PATCH v2 47/74] semihosting: Create semihost_sys_poll_one,
Richard Henderson <=
- [PATCH v2 45/74] semihosting: Use console_out_gf for SYS_WRITE0, Richard Henderson, 2022/05/03
- [PATCH v2 48/74] target/m68k: Eliminate m68k_semi_is_fseek, Richard Henderson, 2022/05/03
- [PATCH v2 55/74] target/mips: Add UHI errno values, Richard Henderson, 2022/05/03
- [PATCH v2 49/74] target/m68k: Make semihosting system only, Richard Henderson, 2022/05/03
- [PATCH v2 52/74] target/nios2: Move nios2-semi.c to nios2_softmmu_ss, Richard Henderson, 2022/05/03
- [PATCH v2 50/74] target/m68k: Use semihosting/syscalls.h, Richard Henderson, 2022/05/03
- [PATCH v2 51/74] target/nios2: Eliminate nios2_semi_is_lseek, Richard Henderson, 2022/05/03
- [PATCH v2 57/74] target/mips: Drop link syscall from semihosting, Richard Henderson, 2022/05/03
- [PATCH v2 53/74] target/nios2: Use semihosting/syscalls.h, Richard Henderson, 2022/05/03
- [PATCH v2 54/74] target/mips: Use an exception for semihosting, Richard Henderson, 2022/05/03