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authorBorislav Petkov <bp@suse.de>2018-12-10 12:21:48 +0100
committerBorislav Petkov <bp@suse.de>2019-01-16 12:40:07 +0100
commit1c1ed4731cc81942a5b25f284a85257573829b9e (patch)
treece2db38caffa432f63294de9b28581596fd7f4d2 /arch/x86/include/asm
parent1c7fc5cbc33980acd13d668f1c8f0313d6ae9fd8 (diff)
downloadlinux-0-day-1c1ed4731cc81942a5b25f284a85257573829b9e.tar.gz
linux-0-day-1c1ed4731cc81942a5b25f284a85257573829b9e.tar.xz
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 <bp@suse.de> Cc: Andy Lutomirski <luto@amacapital.net> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Tom Lendacky <thomas.lendacky@amd.com> Cc: X86 ML <x86@kernel.org> Link: https://lkml.kernel.org/r/20181211222326.14581-2-bp@alien8.de
Diffstat (limited to 'arch/x86/include/asm')
-rw-r--r--arch/x86/include/asm/alternative.h16
1 files 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) \