Tidy arch/um/os-Linux/start_up.c in preparation for host SKAS4 testing.
There are now explicit variables for disabling any particular host
capability.
init_registers is moved out of the skas3 testing because it needs to
happen every time, and the skas3 checks will become optional.
diff --git a/arch/um/include/os.h b/arch/um/include/os.h
index 6f0d1c7..f1c26f5 100644
--- a/arch/um/include/os.h
+++ b/arch/um/include/os.h
@@ -168,7 +168,7 @@ extern int os_fchange_dir(int fd);
/* start_up.c */
extern void os_early_checks(void);
-extern int can_do_skas(void);
+extern void can_do_skas(void);
extern void os_check_bugs(void);
extern void check_host_supports_tls(int *supports_tls, int *tls_min);
diff --git a/arch/um/os-Linux/start_up.c b/arch/um/os-Linux/start_up.c
index 7b81f6c..2576d70 100644
--- a/arch/um/os-Linux/start_up.c
+++ b/arch/um/os-Linux/start_up.c
@@ -23,6 +23,7 @@
#include "mem_user.h"
#include "ptrace_user.h"
#include "registers.h"
+#include "skas.h"
#include "skas_ptrace.h"
static int ptrace_child(void)
@@ -141,14 +142,27 @@ 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;
}
@@ -158,15 +172,12 @@ 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;
@@ -341,6 +352,8 @@ static void __init check_coredump_limit(void)
void __init os_early_checks(void)
{
+ int pid;
+
/* Print out the core dump limits early */
check_coredump_limit();
@@ -350,11 +363,15 @@ void __init os_early_checks(void)
* kernel is running.
*/
check_tmpexec();
+
+ pid = start_ptraced_child();
+ init_registers(pid);
+ stop_ptraced_child(pid, 1, 1);
}
static int __init noprocmm_cmd_param(char *str, int* add)
{
- proc_mm = 0;
+ disable_proc_mm = 1;
return 0;
}
@@ -366,7 +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;
}
@@ -378,7 +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;
}
@@ -398,20 +415,18 @@ 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");
}
- init_registers(pid);
stop_ptraced_child(pid, 1, 1);
}
@@ -435,38 +450,32 @@ static inline void check_skas3_ptrace_ldt(void)
else {
perror("not found");
}
- ptrace_ldt = 0;
}
+ else if (disable_ptrace_ldt)
+ non_fatal("found, but use is disabled\n");
else {
- if (ptrace_ldt)
- non_fatal("found\n");
- else
- non_fatal("found, but use is disabled\n");
+ 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");
+ }
}
-int can_do_skas(void)
+void can_do_skas(void)
{
non_fatal("Checking for the skas3 patch in the host:\n");
@@ -476,8 +485,6 @@ int can_do_skas(void)
if (!proc_mm || !ptrace_faultinfo || !ptrace_ldt)
skas_needs_stub = 1;
-
- return 1;
}
int __init parse_iomem(char *str, int *add)
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