From 6620ef28c812b4782b10adb676580c2847d2bec8 Mon Sep 17 00:00:00 2001 From: Borislav Petkov Date: Sun, 18 Jan 2015 12:57:41 +0100 Subject: [PATCH] x86/lib/clear_page_64.S: Convert to ALTERNATIVE_2 macro Move clear_page() up so that we can get 2-byte forward JMPs when patching: apply_alternatives: feat: 3*32+16, old: (ffffffff8130adb0, len: 5), repl: (ffffffff81d0b859, len: 5) ffffffff8130adb0: alt_insn: 90 90 90 90 90 recompute_jump: new_displ: 0x0000003e ffffffff81d0b859: rpl_insn: eb 3e 66 66 90 even though the compiler generated 5-byte JMPs which we padded with 5 NOPs. Also, make the REP_GOOD version be the default as the majority of machines set REP_GOOD. This way we get to save ourselves the JMP: old insn VA: 0xffffffff813038b0, CPU feat: X86_FEATURE_REP_GOOD, size: 5, padlen: 0 clear_page: ffffffff813038b0 : ffffffff813038b0: e9 0b 00 00 00 jmpq ffffffff813038c0 repl insn: 0xffffffff81cf0e92, size: 0 old insn VA: 0xffffffff813038b0, CPU feat: X86_FEATURE_ERMS, size: 5, padlen: 0 clear_page: ffffffff813038b0 : ffffffff813038b0: e9 0b 00 00 00 jmpq ffffffff813038c0 repl insn: 0xffffffff81cf0e92, size: 5 ffffffff81cf0e92: e9 69 2a 61 ff jmpq ffffffff81303900 ffffffff813038b0 : ffffffff813038b0: e9 69 2a 61 ff jmpq ffffffff8091631e Signed-off-by: Borislav Petkov --- Reading git-format-patch failed