semihosting: add --semihosting-config arg sub-argument

Add new "arg" sub-argument to the --semihosting-config allowing the user
to pass multiple input arguments separately. It is required for example
by UHI semihosting to construct argc and argv.

Also, update ARM semihosting to support new option (at the moment it is
the only target which cares about arguments).

If the semihosting is enabled and no semihosting args have been specified,
then fall back to -kernel/-append. The -append string is split on whitespace
before initializing semihosting.argv[1..n]; this is different from what
QEMU MIPS machines' pseudo-bootloaders do (i.e. argv[1] contains the whole
-append), but is more intuitive from UHI user's point of view and Linux
kernel just does not care as it concatenates argv[1..n] into single cmdline
string anyway.

Signed-off-by: Leon Alrae <leon.alrae@imgtec.com>
Message-id: 1434643256-16858-3-git-send-email-leon.alrae@imgtec.com
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 16 insertions, 5 deletions

diff --git a/qemu-options.hx b/qemu-options.hx
index 5438f9862c..7959dd0b02 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -3351,14 +3351,25 @@ STEXI
 Enable semihosting mode (ARM, M68K, Xtensa only).
 ETEXI
 DEF("semihosting-config", HAS_ARG, QEMU_OPTION_semihosting_config,
-    "-semihosting-config [enable=on|off,]target=native|gdb|auto   semihosting configuration\n",
+    "-semihosting-config [enable=on|off][,target=native|gdb|auto][,arg=str[,...]]\n" \
+    "                semihosting configuration\n",
 QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | QEMU_ARCH_LM32)
 STEXI
-@item -semihosting-config [enable=on|off,]target=native|gdb|auto
+@item -semihosting-config [enable=on|off][,target=native|gdb|auto][,arg=str[,...]]
 @findex -semihosting-config
-Enable semihosting and define where the semihosting calls will be addressed,
-to QEMU (@code{native}) or to GDB (@code{gdb}). The default is @code{auto}, which means
-@code{gdb} during debug sessions and @code{native} otherwise (ARM, M68K, Xtensa only).
+Enable and configure semihosting (ARM, M68K, Xtensa only).
+@table @option
+@item target=@code{native|gdb|auto}
+Defines where the semihosting calls will be addressed, to QEMU (@code{native})
+or to GDB (@code{gdb}). The default is @code{auto}, which means @code{gdb}
+during debug sessions and @code{native} otherwise.
+@item arg=@var{str1},arg=@var{str2},...
+Allows the user to pass input arguments, and can be used multiple times to build
+up a list. The old-style @code{-kernel}/@code{-append} method of passing a
+command line is still supported for backward compatibility. If both the
+@code{--semihosting-config arg} and the @code{-kernel}/@code{-append} are
+specified, the former is passed to semihosting as it always takes precedence.
+@end table
 ETEXI
 DEF("old-param", 0, QEMU_OPTION_old_param,
     "-old-param      old param mode\n", QEMU_ARCH_ARM)