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| author | Borislav Petkov <bp@suse.de> | 2017-03-30 10:44:05 +0300 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2017-03-31 09:08:31 +0300 |
| commit | 952a6c2c094f4eda295f20c42e6e2d73735950fa (patch) | |
| tree | ca6dc9a94f06011cb24660d7aa3de44a4e869a36 /arch/x86/mm | |
| parent | 4af171105144a6475704c1e6024132883d50499e (diff) | |
| download | linux-952a6c2c094f4eda295f20c42e6e2d73735950fa.tar.xz | |
x86/boot/32: Flip the logic in test_wp_bit()
... to have a natural "likely()" in the code flow and thus have the
success case with a branch 99.999% of the times non-taken and function
return code following it instead of jumping to it each time.
This puts the panic() call at the end of the function - it is going to
be practically unreachable anyway.
The C code is a bit more readable too.
No functionality change.
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: boris.ostrovsky@oracle.com
Cc: jgross@suse.com
Cc: thgarnie@google.com
Link: http://lkml.kernel.org/r/20170330080101.ywsf5rg6ilzu4itk@pd.tnic
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/mm')
| -rw-r--r-- | arch/x86/mm/init_32.c | 15 |
1 files changed, 7 insertions, 8 deletions
diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c index 097089a5e4d5..601b8e04e5c6 100644 --- a/arch/x86/mm/init_32.c +++ b/arch/x86/mm/init_32.c @@ -726,19 +726,18 @@ static void __init test_wp_bit(void) { char z = 0; - printk(KERN_INFO - "Checking if this processor honours the WP bit even in supervisor mode..."); + printk(KERN_INFO "Checking if this processor honours the WP bit even in supervisor mode..."); __set_fixmap(FIX_WP_TEST, __pa_symbol(empty_zero_page), PAGE_KERNEL_RO); - if (probe_kernel_write((char *)fix_to_virt(FIX_WP_TEST), &z, 1) == 0) { - printk(KERN_CONT "No.\n"); - panic("Linux doesn't support CPUs with broken WP."); + if (probe_kernel_write((char *)fix_to_virt(FIX_WP_TEST), &z, 1)) { + clear_fixmap(FIX_WP_TEST); + printk(KERN_CONT "Ok.\n"); + return; } - clear_fixmap(FIX_WP_TEST); - - printk(KERN_CONT "Ok.\n"); + printk(KERN_CONT "No.\n"); + panic("Linux doesn't support CPUs with broken WP."); } void __init mem_init(void) |