bwlp/qemu.git/semihosting, branch master

semihosting/arm-compat-semi: Avoid using hardcoded /tmp

2022-10-31T20:37:58+00:00

Use g_get_tmp_dir() to get the directory to use for temporary files. Signed-off-by: Bin Meng Reviewed-by: Alex Bennée Signed-off-by: Alex Bennée Reviewed-by: Philippe Mathieu-Daudé Reviewed-by: Richard Henderson Message-Id: <20221006151927.2079583-2-bmeng.cn@gmail.com> Message-Id: <20221027183637.2772968-11-alex.bennee@linaro.org>

semihosting: update link to spec

2022-10-06T10:53:41+00:00

The old link has moved but it seems the document is now hosted on Arm's github along with a license update to CC-BY-SA-4.0. Signed-off-by: Alex Bennée Reviewed-by: Richard Henderson Message-Id: <20220929114231.583801-42-alex.bennee@linaro.org>

semihosting: Allow optional use of semihosting from userspace

2022-09-13T16:18:21+00:00

Currently our semihosting implementations generally prohibit use of semihosting calls in system emulation from the guest userspace. This is a very long standing behaviour justified originally "to provide some semblance of security" (since code with access to the semihosting ABI can do things like read and write arbitrary files on the host system). However, it is sometimes useful to be able to run trusted guest code which performs semihosting calls from guest userspace, notably for test code. Add a command line suboption to the existing semihosting-config option group so that you can explicitly opt in to semihosting from guest userspace with -semihosting-config userspace=on (There is no equivalent option for the user-mode emulator, because there by definition all code runs in userspace and has access to semihosting already.) This commit adds the infrastructure for the command line option and adds a bool 'is_user' parameter to the function semihosting_userspace_enabled() that target code can use to check whether it should be permitting the semihosting call for userspace. It mechanically makes all the callsites pass 'false', so they continue checking "is semihosting enabled in general". Subsequent commits will make each target that implements semihosting honour the userspace=on option by passing the correct value and removing whatever "don't do this for userspace" checking they were doing by hand. Signed-off-by: Peter Maydell Acked-by: Alex Bennée Reviewed-by: Alistair Francis Reviewed-by: Philippe Mathieu-Daudé Reviewed-by: Richard Henderson Message-Id: <20220822141230.3658237-2-peter.maydell@linaro.org> Signed-off-by: Richard Henderson

semihosting: Fix handling of buffer in TARGET_SYS_TMPNAM

2022-07-29T08:48:01+00:00

The TARGET_SYS_TMPNAM implementation has two bugs spotted by Coverity: * confusion about whether 'len' has the length of the string including or excluding the terminating NUL means we lock_user() len bytes of memory but memcpy() len + 1 bytes * In the error-exit cases we forget to free() the buffer that asprintf() returned to us Resolves: Coverity CID 1490285, 1490289 Signed-off-by: Peter Maydell Reviewed-by: Richard Henderson Message-Id: <20220719121110.225657-5-peter.maydell@linaro.org> Signed-off-by: Alex Bennée Message-Id: <20220725140520.515340-10-alex.bennee@linaro.org>

semihosting: Check for errors on SET_ARG()

2022-07-29T08:48:01+00:00

The SET_ARG() macro returns an error indication; we check this in the TARGET_SYS_GET_CMDLINE case but not when we use it in implementing TARGET_SYS_ELAPSED. Check for and handle the errors via the do_fault codepath, and update the comment documenting the SET_ARG() and GET_ARG() macros to note how they handle memory access errors. Resolves: Coverity CID 1490287 Signed-off-by: Peter Maydell Reviewed-by: Richard Henderson Message-Id: <20220719121110.225657-4-peter.maydell@linaro.org> Signed-off-by: Alex Bennée Message-Id: <20220725140520.515340-9-alex.bennee@linaro.org>

semihosting: Don't copy buffer after console_write()

2022-07-29T08:48:01+00:00

The console_write() semihosting function outputs guest data from a buffer; it doesn't update that buffer. It therefore doesn't need to pass a length value to unlock_user(), but can pass 0, meaning "do not copy any data back to the guest memory". Signed-off-by: Peter Maydell Reviewed-by: Richard Henderson Message-Id: <20220719121110.225657-3-peter.maydell@linaro.org> Signed-off-by: Alex Bennée Message-Id: <20220725140520.515340-8-alex.bennee@linaro.org>

semihosting: Don't return negative values on qemu_semihosting_console_write() failure

2022-07-29T08:48:01+00:00

The documentation comment for qemu_semihosting_console_write() says * Returns: number of bytes written -- this should only ever be short * on some sort of i/o error. and the callsites rely on this. However, the implementation code path which sends console output to a chardev doesn't honour this, and will return negative values on error. Bring it into line with the other implementation codepaths and the documentation, so that it returns 0 on error. Spotted by Coverity, because console_write() passes the return value to unlock_user(), which doesn't accept a negative length. Resolves: Coverity CID 1490288 Signed-off-by: Peter Maydell Reviewed-by: Richard Henderson Message-Id: <20220719121110.225657-2-peter.maydell@linaro.org> Signed-off-by: Alex Bennée Reviewed-by: Philippe Mathieu-Daudé Message-Id: <20220725140520.515340-7-alex.bennee@linaro.org>

semihosting: Remove qemu_semihosting_log_out

2022-07-12T20:32:12+00:00

The function is no longer used. Reviewed-by: Philippe Mathieu-Daudé Signed-off-by: Richard Henderson Message-Id: <20220628111701.677216-7-richard.henderson@linaro.org> Signed-off-by: Philippe Mathieu-Daudé

semihosting: Create semihost_sys_poll_one

2022-06-27T23:11:37+00:00

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. Reviewed-by: Luc Michel Signed-off-by: Richard Henderson

semihosting: Remove qemu_semihosting_console_outs

2022-06-27T23:11:20+00:00

This function has been replaced by *_write. Reviewed-by: Luc Michel Reviewed-by: Alex Bennée Signed-off-by: Richard Henderson