diff options
Diffstat (limited to 'arch/um/sys-i386/bugs.c')
| -rw-r--r-- | arch/um/sys-i386/bugs.c | 40 |
1 files changed, 31 insertions, 9 deletions
diff --git a/arch/um/sys-i386/bugs.c b/arch/um/sys-i386/bugs.c index 5ee4c366074..797945cd3df 100644 --- a/arch/um/sys-i386/bugs.c +++ b/arch/um/sys-i386/bugs.c @@ -10,11 +10,41 @@ #include "os.h" #include "task.h" #include "user.h" +#include "sysdep/archsetjmp.h" #define MAXTOKEN 64 /* Set during early boot */ int host_has_cmov = 1; +static jmp_buf cmov_test_return; + +static void cmov_sigill_test_handler(int sig) +{ + host_has_cmov = 0; + longjmp(cmov_test_return, 1); +} + +static void test_for_host_cmov(void) +{ + struct sigaction old, new; + + printk(UM_KERN_INFO "Checking for host processor cmov support..."); + new.sa_handler = cmov_sigill_test_handler; + + /* Make sure that SIGILL is enabled after the handler longjmps back */ + new.sa_flags = SA_NODEFER; + sigemptyset(&new.sa_mask); + sigaction(SIGILL, &new, &old); + + if (setjmp(cmov_test_return) == 0) { + unsigned long foo = 0; + __asm__ __volatile__("cmovz %0, %1" : "=r" (foo) : "0" (foo)); + printk(UM_KERN_CONT "Yes\n"); + } else + printk(UM_KERN_CONT "No\n"); + + sigaction(SIGILL, &old, &new); +} static char token(int fd, char *buf, int len, char stop) { @@ -153,15 +183,7 @@ void arch_init_thread(void) void arch_check_bugs(void) { - int have_it; - - if (os_access("/proc/cpuinfo", OS_ACC_R_OK) < 0) { - printk(UM_KERN_ERR "/proc/cpuinfo not available - skipping CPU " - "capability checks\n"); - return; - } - if (check_cpu_flag("cmov", &have_it)) - host_has_cmov = have_it; + test_for_host_cmov(); } int arch_handle_signal(int sig, struct uml_pt_regs *regs) |