From 1c1ed4731cc81942a5b25f284a85257573829b9e Mon Sep 17 00:00:00 2001 From: Borislav Petkov Date: Mon, 10 Dec 2018 12:21:48 +0100 Subject: [PATCH] x86/alternatives: Add macro comments ... so that when one stares at the .s output, one can find her way around the resulting asm magic. With it, ALTERNATIVE looks like this now: # ALT: oldnstr 661: ... 662: # ALT: padding .skip ... 663: .pushsection .altinstructions,"a" ... .popsection .pushsection .altinstr_replacement, "ax" # ALT: replacement 1 6641: ... 6651: .popsection Merge __OLDINSTR() into OLDINSTR(), while at it. No functional changes. Signed-off-by: Borislav Petkov Cc: Andy Lutomirski Cc: "H. Peter Anvin" Cc: Josh Poimboeuf Cc: Peter Zijlstra Cc: Tom Lendacky Cc: X86 ML Link: https://lkml.kernel.org/r/20181211222326.14581-2-bp@alien8.de --- arch/x86/include/asm/alternative.h | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-) diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h index 0660e14690c8..373e2baca6ce 100644 --- a/arch/x86/include/asm/alternative.h +++ b/arch/x86/include/asm/alternative.h @@ -94,13 +94,12 @@ static inline int alternatives_text_reserved(void *start, void *end) #define alt_total_slen alt_end_marker"b-661b" #define alt_rlen(num) e_replacement(num)"f-"b_replacement(num)"f" -#define __OLDINSTR(oldinstr, num) \ +#define OLDINSTR(oldinstr, num) \ + "# ALT: oldnstr\n" \ "661:\n\t" oldinstr "\n662:\n" \ + "# ALT: padding\n" \ ".skip -(((" alt_rlen(num) ")-(" alt_slen ")) > 0) * " \ - "((" alt_rlen(num) ")-(" alt_slen ")),0x90\n" - -#define OLDINSTR(oldinstr, num) \ - __OLDINSTR(oldinstr, num) \ + "((" alt_rlen(num) ")-(" alt_slen ")),0x90\n" \ alt_end_marker ":\n" /* @@ -116,7 +115,9 @@ static inline int alternatives_text_reserved(void *start, void *end) * additionally longer than the first replacement alternative. */ #define OLDINSTR_2(oldinstr, num1, num2) \ + "# ALT: oldinstr2\n" \ "661:\n\t" oldinstr "\n662:\n" \ + "# ALT: padding2\n" \ ".skip -((" alt_max_short(alt_rlen(num1), alt_rlen(num2)) " - (" alt_slen ")) > 0) * " \ "(" alt_max_short(alt_rlen(num1), alt_rlen(num2)) " - (" alt_slen ")), 0x90\n" \ alt_end_marker ":\n" @@ -129,8 +130,9 @@ static inline int alternatives_text_reserved(void *start, void *end) " .byte " alt_rlen(num) "\n" /* replacement len */ \ " .byte " alt_pad_len "\n" /* pad len */ -#define ALTINSTR_REPLACEMENT(newinstr, feature, num) /* replacement */ \ - b_replacement(num)":\n\t" newinstr "\n" e_replacement(num) ":\n\t" +#define ALTINSTR_REPLACEMENT(newinstr, feature, num) /* replacement */ \ + "# ALT: replacement " #num "\n" \ + b_replacement(num)":\n\t" newinstr "\n" e_replacement(num) ":\n" /* alternative assembly primitive: */ #define ALTERNATIVE(oldinstr, newinstr, feature) \ -- 2.45.2