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uml: redo host capability detection and disabling 

Redo how host capabilities are recorded at startup and disabled on the
command line.

There are now explicit variables saying what's been disabled by the
command line rather than the implicitness of the have_* variable being
zero.  The capability variables now start at zero and are set to one
as their capabilities are found to be present on the host.

Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Cc: WANG Cong <xiyou.wangcong@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Jeff Dike 2008-05-12 14:01:47 -07:00 committed by Linus Torvalds
parent c714a534d8
commit 53c2587874
1 changed files with 42 additions and 41 deletions
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83
arch/um/os-Linux/start_up.c
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@ -23,6 +23,7 @@
#include "mem_user.h"
#include "ptrace_user.h"
#include "registers.h"
#include "skas.h"
#include "skas_ptrace.h"
static void ptrace_child(void)
@ -140,14 +141,27 @@ static int stop_ptraced_child(int pid, int exitcode, int mustexit)
}
/* Changed only during early boot */
int ptrace_faultinfo = 1;
int ptrace_ldt = 1;
int proc_mm = 1;
int skas_needs_stub = 0;
int ptrace_faultinfo;
static int disable_ptrace_faultinfo;
int ptrace_ldt;
static int disable_ptrace_ldt;
int proc_mm;
static int disable_proc_mm;
int have_switch_mm;
static int disable_switch_mm;
int skas_needs_stub;
static int __init skas0_cmd_param(char *str, int* add)
{
ptrace_faultinfo = proc_mm = 0;
disable_ptrace_faultinfo = 1;
disable_ptrace_ldt = 1;
disable_proc_mm = 1;
disable_switch_mm = 1;
return 0;
}
@ -157,15 +171,12 @@ static int __init mode_skas0_cmd_param(char *str, int* add)
__attribute__((alias("skas0_cmd_param")));
__uml_setup("skas0", skas0_cmd_param,
"skas0\n"
" Disables SKAS3 usage, so that SKAS0 is used, unless \n"
" you specify mode=tt.\n\n");
"skas0\n"
" Disables SKAS3 and SKAS4 usage, so that SKAS0 is used\n\n");
__uml_setup("mode=skas0", mode_skas0_cmd_param,
"mode=skas0\n"
" Disables SKAS3 usage, so that SKAS0 is used, unless you \n"
" specify mode=tt. Note that this was recently added - on \n"
" older kernels you must use simply \"skas0\".\n\n");
"mode=skas0\n"
" Disables SKAS3 and SKAS4 usage, so that SKAS0 is used.\n\n");
/* Changed only during early boot */
static int force_sysemu_disabled = 0;
@ -360,7 +371,7 @@ void __init os_early_checks(void)
static int __init noprocmm_cmd_param(char *str, int* add)
{
proc_mm = 0;
disable_proc_mm = 1;
return 0;
}
@ -372,7 +383,7 @@ __uml_setup("noprocmm", noprocmm_cmd_param,
static int __init noptracefaultinfo_cmd_param(char *str, int* add)
{
ptrace_faultinfo = 0;
disable_ptrace_faultinfo = 1;
return 0;
}
@ -384,7 +395,7 @@ __uml_setup("noptracefaultinfo", noptracefaultinfo_cmd_param,
static int __init noptraceldt_cmd_param(char *str, int* add)
{
ptrace_ldt = 0;
disable_ptrace_ldt = 1;
return 0;
}
@ -404,17 +415,15 @@ static inline void check_skas3_ptrace_faultinfo(void)
n = ptrace(PTRACE_FAULTINFO, pid, 0, &fi);
if (n < 0) {
ptrace_faultinfo = 0;
if (errno == EIO)
non_fatal("not found\n");
else
perror("not found");
}
} else if (disable_ptrace_faultinfo)
non_fatal("found but disabled on command line\n");
else {
if (!ptrace_faultinfo)
non_fatal("found but disabled on command line\n");
else
non_fatal("found\n");
ptrace_faultinfo = 1;
non_fatal("found\n");
}
stop_ptraced_child(pid, 1, 1);
@ -437,38 +446,30 @@ static inline void check_skas3_ptrace_ldt(void)
if (n < 0) {
if (errno == EIO)
non_fatal("not found\n");
else {
perror("not found");
}
ptrace_ldt = 0;
}
else {
if (ptrace_ldt)
non_fatal("found\n");
else
non_fatal("found, but use is disabled\n");
perror("not found");
} else if (disable_ptrace_ldt)
non_fatal("found, but use is disabled\n");
else {
ptrace_ldt = 1;
non_fatal("found\n");
}
stop_ptraced_child(pid, 1, 1);
#else
/* PTRACE_LDT might be disabled via cmdline option.
* We want to override this, else we might use the stub
* without real need
*/
ptrace_ldt = 1;
#endif
}
static inline void check_skas3_proc_mm(void)
{
non_fatal(" - /proc/mm...");
if (access("/proc/mm", W_OK) < 0) {
proc_mm = 0;
if (access("/proc/mm", W_OK) < 0)
perror("not found");
}
else if (!proc_mm)
else if (disable_proc_mm)
non_fatal("found but disabled on command line\n");
else non_fatal("found\n");
else {
proc_mm = 1;
non_fatal("found\n");
}
}
void can_do_skas(void)