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authorKeith Packard <keithp@keithp.com>2019-11-04 12:42:30 -0800
committerAlex Bennée <alex.bennee@linaro.org>2020-01-09 11:41:29 +0000
commit8de702cb677c8381fb702cae252d6b69aa4c653b (patch)
treeccfa04a054ffba8c063c4c67da4fb8f6760f1531 /linux-user
parent4ff5ef9e911c670ca10cdd36dd27c5395ec2c753 (diff)
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semihosting: add qemu_semihosting_console_inc for SYS_READC
Provides a blocking call to read a character from the console using semihosting.chardev, if specified. This takes some careful command line options to use stdio successfully as the serial ports, monitor and semihost all want to use stdio. Here's a sample set of command line options which share stdio between semihost, monitor and serial ports: qemu \ -chardev stdio,mux=on,id=stdio0 \ -serial chardev:stdio0 \ -semihosting-config enable=on,chardev=stdio0 \ -mon chardev=stdio0,mode=readline This creates a chardev hooked to stdio and then connects all of the subsystems to it. A shorter mechanism would be good to hear about. Signed-off-by: Keith Packard <keithp@keithp.com> Message-Id: <20191104204230.12249-1-keithp@keithp.com> [AJB: fixed up deadlock, minor commit title reword] Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Keith Packard <keithp@keithp.com> Tested-by: Keith Packard <keithp@keithp.com> Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Diffstat (limited to 'linux-user')
-rw-r--r--linux-user/arm/semihost.c27
1 files changed, 27 insertions, 0 deletions
diff --git a/linux-user/arm/semihost.c b/linux-user/arm/semihost.c
index a16b525..a1f0f60 100644
--- a/linux-user/arm/semihost.c
+++ b/linux-user/arm/semihost.c
@@ -14,6 +14,7 @@
#include "cpu.h"
#include "hw/semihosting/console.h"
#include "qemu.h"
+#include <termios.h>
int qemu_semihosting_console_outs(CPUArchState *env, target_ulong addr)
{
@@ -47,3 +48,29 @@ void qemu_semihosting_console_outc(CPUArchState *env, target_ulong addr)
}
}
}
+
+/*
+ * For linux-user we can safely block. However as we want to return as
+ * soon as a character is read we need to tweak the termio to disable
+ * line buffering. We restore the old mode afterwards in case the
+ * program is expecting more normal behaviour. This is slow but
+ * nothing using semihosting console reading is expecting to be fast.
+ */
+target_ulong qemu_semihosting_console_inc(CPUArchState *env)
+{
+ uint8_t c;
+ struct termios old_tio, new_tio;
+
+ /* Disable line-buffering and echo */
+ tcgetattr(STDIN_FILENO, &old_tio);
+ new_tio = old_tio;
+ new_tio.c_lflag &= (~ICANON & ~ECHO);
+ tcsetattr(STDIN_FILENO, TCSANOW, &new_tio);
+
+ c = getchar();
+
+ /* restore config */
+ tcsetattr(STDIN_FILENO, TCSANOW, &old_tio);
+
+ return (target_ulong) c;
+}