diff options
Diffstat (limited to 'common/recipes-kernel/linux/linux-yocto-4.9.21/0059-x86-alternatives-Fix-optimize_nops-checking.patch')
| -rw-r--r-- | common/recipes-kernel/linux/linux-yocto-4.9.21/0059-x86-alternatives-Fix-optimize_nops-checking.patch | 56 |
1 files changed, 56 insertions, 0 deletions
diff --git a/common/recipes-kernel/linux/linux-yocto-4.9.21/0059-x86-alternatives-Fix-optimize_nops-checking.patch b/common/recipes-kernel/linux/linux-yocto-4.9.21/0059-x86-alternatives-Fix-optimize_nops-checking.patch new file mode 100644 index 00000000..b954c23c --- /dev/null +++ b/common/recipes-kernel/linux/linux-yocto-4.9.21/0059-x86-alternatives-Fix-optimize_nops-checking.patch @@ -0,0 +1,56 @@ +From 1ac5fc23c160f82956aa23fd595206a15d80d742 Mon Sep 17 00:00:00 2001 +From: Borislav Petkov <bp@suse.de> +Date: Wed, 10 Jan 2018 12:28:16 +0100 +Subject: [PATCH 059/103] x86/alternatives: Fix optimize_nops() checking + +commit 612e8e9350fd19cae6900cf36ea0c6892d1a0dca upstream. + +The alternatives code checks only the first byte whether it is a NOP, but +with NOPs in front of the payload and having actual instructions after it +breaks the "optimized' test. + +Make sure to scan all bytes before deciding to optimize the NOPs in there. + +Reported-by: David Woodhouse <dwmw2@infradead.org> +Signed-off-by: Borislav Petkov <bp@suse.de> +Signed-off-by: Thomas Gleixner <tglx@linutronix.de> +Cc: Tom Lendacky <thomas.lendacky@amd.com> +Cc: Andi Kleen <ak@linux.intel.com> +Cc: Tim Chen <tim.c.chen@linux.intel.com> +Cc: Peter Zijlstra <peterz@infradead.org> +Cc: Jiri Kosina <jikos@kernel.org> +Cc: Dave Hansen <dave.hansen@intel.com> +Cc: Andi Kleen <andi@firstfloor.org> +Cc: Andrew Lutomirski <luto@kernel.org> +Cc: Linus Torvalds <torvalds@linux-foundation.org> +Cc: Greg Kroah-Hartman <gregkh@linux-foundation.org> +Cc: Paul Turner <pjt@google.com> +Link: https://lkml.kernel.org/r/20180110112815.mgciyf5acwacphkq@pd.tnic +Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> +Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> +--- + arch/x86/kernel/alternative.c | 7 +++++-- + 1 file changed, 5 insertions(+), 2 deletions(-) + +diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c +index 5cb272a..10d5a3d 100644 +--- a/arch/x86/kernel/alternative.c ++++ b/arch/x86/kernel/alternative.c +@@ -340,9 +340,12 @@ recompute_jump(struct alt_instr *a, u8 *orig_insn, u8 *repl_insn, u8 *insnbuf) + static void __init_or_module optimize_nops(struct alt_instr *a, u8 *instr) + { + unsigned long flags; ++ int i; + +- if (instr[0] != 0x90) +- return; ++ for (i = 0; i < a->padlen; i++) { ++ if (instr[i] != 0x90) ++ return; ++ } + + local_irq_save(flags); + add_nops(instr + (a->instrlen - a->padlen), a->padlen); +-- +2.7.4 + |