bsd-user: various helper routines for sysctl

cap_memory - Caps the memory to just below MAXINT
scale_to_guest_pages - Account for difference in host / guest page size
h2g_long_sat - converts a int64_t to a int32_t, saturating at max / min values
h2g_ulong_sat - converts a uint64_t to a uint32_t, saturating at max value

Signed-off-by: Warner Losh <imp@bsdimp.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
This commit is contained in:
Warner Losh 2023-02-13 16:02:03 -07:00
parent fb96f5dfed
commit 0867507857
1 changed files with 86 additions and 0 deletions

View File

@ -21,6 +21,92 @@
#include "qemu.h"
#include "target_arch_sysarch.h"
#include <sys/sysctl.h>
/*
* Length for the fixed length types.
* 0 means variable length for strings and structures
* Compare with sys/kern_sysctl.c ctl_size
* Note: Not all types appear to be used in-tree.
*/
static const int G_GNUC_UNUSED guest_ctl_size[CTLTYPE + 1] = {
[CTLTYPE_INT] = sizeof(abi_int),
[CTLTYPE_UINT] = sizeof(abi_uint),
[CTLTYPE_LONG] = sizeof(abi_long),
[CTLTYPE_ULONG] = sizeof(abi_ulong),
[CTLTYPE_S8] = sizeof(int8_t),
[CTLTYPE_S16] = sizeof(int16_t),
[CTLTYPE_S32] = sizeof(int32_t),
[CTLTYPE_S64] = sizeof(int64_t),
[CTLTYPE_U8] = sizeof(uint8_t),
[CTLTYPE_U16] = sizeof(uint16_t),
[CTLTYPE_U32] = sizeof(uint32_t),
[CTLTYPE_U64] = sizeof(uint64_t),
};
static const int G_GNUC_UNUSED host_ctl_size[CTLTYPE + 1] = {
[CTLTYPE_INT] = sizeof(int),
[CTLTYPE_UINT] = sizeof(u_int),
[CTLTYPE_LONG] = sizeof(long),
[CTLTYPE_ULONG] = sizeof(u_long),
[CTLTYPE_S8] = sizeof(int8_t),
[CTLTYPE_S16] = sizeof(int16_t),
[CTLTYPE_S32] = sizeof(int32_t),
[CTLTYPE_S64] = sizeof(int64_t),
[CTLTYPE_U8] = sizeof(uint8_t),
[CTLTYPE_U16] = sizeof(uint16_t),
[CTLTYPE_U32] = sizeof(uint32_t),
[CTLTYPE_U64] = sizeof(uint64_t),
};
#ifdef TARGET_ABI32
/*
* Limit the amount of available memory to be most of the 32-bit address
* space. 0x100c000 was arrived at through trial and error as a good
* definition of 'most'.
*/
static const abi_ulong guest_max_mem = UINT32_MAX - 0x100c000 + 1;
static abi_ulong G_GNUC_UNUSED cap_memory(uint64_t mem)
{
return MIN(guest_max_mem, mem);
}
#endif
static abi_ulong G_GNUC_UNUSED scale_to_guest_pages(uint64_t pages)
{
/* Scale pages from host to guest */
pages = muldiv64(pages, qemu_real_host_page_size(), TARGET_PAGE_SIZE);
#ifdef TARGET_ABI32
/* cap pages if need be */
pages = MIN(pages, guest_max_mem / (abi_ulong)TARGET_PAGE_SIZE);
#endif
return pages;
}
#ifdef TARGET_ABI32
/* Used only for TARGET_ABI32 */
static abi_long G_GNUC_UNUSED h2g_long_sat(long l)
{
if (l > INT32_MAX) {
l = INT32_MAX;
} else if (l < INT32_MIN) {
l = INT32_MIN;
}
return l;
}
static abi_ulong G_GNUC_UNUSED h2g_ulong_sat(u_long ul)
{
return MIN(ul, UINT32_MAX);
}
#endif
/*
* placeholder until bsd-user downstream upstreams this with its thread support
*/
#define bsd_get_ncpu() 1
/* sysarch() is architecture dependent. */
abi_long do_freebsd_sysarch(void *cpu_env, abi_long arg1, abi_long arg2)
{