On 10 September 2013 23:07, Richard Henderson <r...@twiddle.net> wrote:
> Abstract away dependence on a system implementation of getauxval.
>
> Signed-off-by: Richard Henderson <r...@twiddle.net>
There are unfortunately some trivial conflicts now so
this series needs a respin :-(
> ---
> include/qemu/osdep.h | 20 ++++++++++++
> linux-user/main.c | 1 +
> util/Makefile.objs | 1 +
> util/getauxval.c | 91
> ++++++++++++++++++++++++++++++++++++++++++++++++++++
> vl.c | 1 +
> 5 files changed, 114 insertions(+)
> create mode 100644 util/getauxval.c
>
> diff --git a/include/qemu/osdep.h b/include/qemu/osdep.h
> index 26136f1..8d1948b 100644
> --- a/include/qemu/osdep.h
> +++ b/include/qemu/osdep.h
> @@ -215,4 +215,24 @@ bool fips_get_state(void);
> */
> char *qemu_get_local_state_pathname(const char *relative_pathname);
>
> +/* Return a value for an AT_* type in the auxiliary vector. Return 0 if the
> + * key is not present. We attempt to emulate AT_HWCAP and AT_PLATFORM as
> + * best we can when real host support is not present.
> + */
Would be nice for these to be in the proper doc-comment format.
> +#ifdef _WIN32
> +static inline unsigned long qemu_getauxval(unsigned long type) { return 0; }
> +#else
> +unsigned long qemu_getauxval(unsigned long type);
> +#endif
> +
> +/* If supported and required, locate the auxiliary vector at program startup.
> + *
> + * @envp must be the third argument to main.
> + */
> +#if defined(CONFIG_GETAUXVAL) || defined(_WIN32)
> +static inline void qemu_init_auxval(char **envp) { }
> +#else
> +void qemu_init_auxval(char **envp);
> +#endif
> +
> #endif
> diff --git a/linux-user/main.c b/linux-user/main.c
> index 5c2f7b2..ebd9cf4 100644
> --- a/linux-user/main.c
> +++ b/linux-user/main.c
> @@ -3553,6 +3553,7 @@ int main(int argc, char **argv, char **envp)
>
> module_call_init(MODULE_INIT_QOM);
>
> + qemu_init_auxval(envp);
> qemu_cache_utils_init(envp);
>
> if ((envlist = envlist_create()) == NULL) {
> diff --git a/util/Makefile.objs b/util/Makefile.objs
> index dc72ab0..8e0c929 100644
> --- a/util/Makefile.objs
> +++ b/util/Makefile.objs
> @@ -11,3 +11,4 @@ util-obj-y += iov.o aes.o qemu-config.o qemu-sockets.o
> uri.o notify.o
> util-obj-y += qemu-option.o qemu-progress.o
> util-obj-y += hexdump.o
> util-obj-y += crc32c.o
> +util-obj-y += getauxval.o
> diff --git a/util/getauxval.c b/util/getauxval.c
> new file mode 100644
> index 0000000..59f53ff
> --- /dev/null
> +++ b/util/getauxval.c
> @@ -0,0 +1,91 @@
> +/*
> + * QEMU access to the auxiliary vector
> + *
> + * Copyright (C) 2013 Red Hat, Inc
> + *
> + * Permission is hereby granted, free of charge, to any person obtaining a
> copy
> + * of this software and associated documentation files (the "Software"), to
> deal
> + * in the Software without restriction, including without limitation the
> rights
> + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
> + * copies of the Software, and to permit persons to whom the Software is
> + * furnished to do so, subject to the following conditions:
> + *
> + * The above copyright notice and this permission notice shall be included in
> + * all copies or substantial portions of the Software.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
> + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
> FROM,
> + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
> + * THE SOFTWARE.
> + */
> +
> +#include "qemu-common.h"
> +#include "qemu/osdep.h"
> +
> +#ifdef CONFIG_GETAUXVAL
> +/* Don't inline this in qemu/osdep.h, because pulling in <sys/auxv.h> for
> + the system declaration of getauxval pulls in the system <elf.h>, which
> + conflicts with qemu's version. */
Ugh, but that's a cleanup for another day I guess.
> +
> +#include <sys/auxv.h>
> +
> +unsigned long qemu_getauxval(unsigned long key)
> +{
> + return getauxval(key);
> +}
> +#elif !defined(_WIN32)
> +#include "elf.h"
> +
> +/* Our elf.h doesn't contain Elf32_auxv_t and Elf64_auxv_t, which is ok
> because
> + that just makes it easier to define it properly for the host here. */
> +typedef struct {
> + unsigned long a_type;
> + unsigned long a_val;
> +} ElfW_auxv_t;
> +
> +static const ElfW_auxv_t *auxv;
> +
> +void qemu_init_auxval(char **envp)
> +{
> +#ifdef __linux__
> + /* The auxiliary vector is located just beyond the initial environment.
> */
> + while (*envp++ != NULL)
> + continue;
Braces.
> + auxv = (const ElfW_auxv_t *)envp;
> +#endif
> +}
> +
> +static const char *default_platform(void)
> +{
> + return NULL;
> +}
> +
> +static unsigned long default_hwcap(void)
> +{
> + return 0;
> +}
> +
> +unsigned long qemu_getauxval(unsigned long type)
> +{
> + /* If we were able to find the auxiliary vector, use it. */
> + if (auxv) {
> + const ElfW_auxv_t *a;
> + for (a = auxv; a->a_type != 0; a++) {
> + if (a->a_type == type) {
> + return a->a_val;
> + }
> + }
> + }
> +
> + /* Otherwise, guess defaults for the host based on compiler flags. */
> + if (type == AT_HWCAP) {
> + return default_hwcap();
> + } else if (type == AT_PLATFORM) {
> + return (unsigned long)default_platform();
> + }
Why is the default for Windows a hardcoded "always zero" but
the default for posix-not-Linux this set of guessed defaults
(which seem to be zero anyway but via a different level of
indirection)?
> + return 0;
> +}
> +#endif
> diff --git a/vl.c b/vl.c
> index b4b119a..35eff6a 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -2967,6 +2967,7 @@ int main(int argc, char **argv, char **envp)
> init_clocks();
> rtc_clock = QEMU_CLOCK_HOST;
>
> + qemu_init_auxval(envp);
> qemu_cache_utils_init(envp);
>
> QLIST_INIT (&vm_change_state_head);
> --
> 1.8.1.4
>
>
-- PMM
