UbiquitousOS
/
OpenCloudOS-Kernel
mirror of https://gitee.com/OpenCloudOS/OpenCloudOS-Kernel.git
11
0
Fork 0
Code Issues Projects Releases Wiki Activity

uml: improve detection of host cmov 

This patch introduces a new way of checking for the cmov instruction.  I use
signal handling instead of reading /proc/cpuinfo.

[ jdike - Fiddled the asm to make it obvious that it didn't mess with
any in-use registers and made test_for_host_cmov void ]

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Karol Swietlicki <magotari@gmail.com>
Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Karol Swietlicki 2008-02-04 22:30:38 -08:00 committed by Linus Torvalds
parent 0ba9d3f91d
commit 235a6f06eb
2 changed files with 32 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
arch/um/include/common-offsets.h
View File

@ -18,6 +18,7 @@ DEFINE_STR(UM_KERN_WARNING, KERN_WARNING);
DEFINE_STR(UM_KERN_NOTICE, KERN_NOTICE);
DEFINE_STR(UM_KERN_INFO, KERN_INFO);
DEFINE_STR(UM_KERN_DEBUG, KERN_DEBUG);
DEFINE_STR(UM_KERN_CONT, KERN_CONT);
DEFINE(UM_ELF_CLASS, ELF_CLASS);
DEFINE(UM_ELFCLASS32, ELFCLASS32);

40
arch/um/sys-i386/bugs.c
View File

@ -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)