4.15-stable review patch. If anyone has any objections, please let me know.
------------------ From: Josh Poimboeuf [email protected] commit 12c69f1e94c89d40696e83804dd2f0965b5250cd The 'noreplace-paravirt' option disables paravirt patching, leaving the original pv indirect calls in place. That's highly incompatible with retpolines, unless we want to uglify paravirt even further and convert the paravirt calls to retpolines. As far as I can tell, the option doesn't seem to be useful for much other than introducing surprising corner cases and making the kernel vulnerable to Spectre v2. It was probably a debug option from the early paravirt days. So just remove it. Signed-off-by: Josh Poimboeuf <[email protected]> Signed-off-by: Thomas Gleixner <[email protected]> Reviewed-by: Juergen Gross <[email protected]> Cc: Andrea Arcangeli <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Andi Kleen <[email protected]> Cc: Ashok Raj <[email protected]> Cc: Greg KH <[email protected]> Cc: Jun Nakajima <[email protected]> Cc: Tim Chen <[email protected]> Cc: Rusty Russell <[email protected]> Cc: Dave Hansen <[email protected]> Cc: Asit Mallick <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Jason Baron <[email protected]> Cc: Paolo Bonzini <[email protected]> Cc: Alok Kataria <[email protected]> Cc: Arjan Van De Ven <[email protected]> Cc: David Woodhouse <[email protected]> Cc: Dan Williams <[email protected]> Link: https://lkml.kernel.org/r/20180131041333.2x6blhxirc2kclrq@treble Signed-off-by: Greg Kroah-Hartman <[email protected]> --- Documentation/admin-guide/kernel-parameters.txt | 2 -- arch/x86/kernel/alternative.c | 14 -------------- 2 files changed, 16 deletions(-) --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -2742,8 +2742,6 @@ norandmaps Don't use address space randomization. Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space - noreplace-paravirt [X86,IA-64,PV_OPS] Don't patch paravirt_ops - noreplace-smp [X86-32,SMP] Don't replace SMP instructions with UP alternatives --- a/arch/x86/kernel/alternative.c +++ b/arch/x86/kernel/alternative.c @@ -46,17 +46,6 @@ static int __init setup_noreplace_smp(ch } __setup("noreplace-smp", setup_noreplace_smp); -#ifdef CONFIG_PARAVIRT -static int __initdata_or_module noreplace_paravirt = 0; - -static int __init setup_noreplace_paravirt(char *str) -{ - noreplace_paravirt = 1; - return 1; -} -__setup("noreplace-paravirt", setup_noreplace_paravirt); -#endif - #define DPRINTK(fmt, args...) \ do { \ if (debug_alternative) \ @@ -599,9 +588,6 @@ void __init_or_module apply_paravirt(str struct paravirt_patch_site *p; char insnbuf[MAX_PATCH_LEN]; - if (noreplace_paravirt) - return; - for (p = start; p < end; p++) { unsigned int used;
