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authorDave Airlie <airlied@redhat.com>2015-04-20 11:32:26 +1000
committerDave Airlie <airlied@redhat.com>2015-04-20 13:05:20 +1000
commit2c33ce009ca2389dbf0535d0672214d09738e35e (patch)
tree6186a6458c3c160385d794a23eaf07c786a9e61b /arch/x86/include/asm/alternative.h
parentmedia-bus: Fixup RGB444_1X12, RGB565_1X16, and YUV8_1X24 media bus format (diff)
parentMerge branch 'turbostat' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux (diff)
downloadlinux-dev-2c33ce009ca2389dbf0535d0672214d09738e35e.tar.xz
linux-dev-2c33ce009ca2389dbf0535d0672214d09738e35e.zip
Merge Linus master into drm-next
The merge is clean, but the arm build fails afterwards, due to API changes in the regulator tree. I've included the patch into the merge to fix the build. Signed-off-by: Dave Airlie <airlied@redhat.com>
Diffstat (limited to 'arch/x86/include/asm/alternative.h')
-rw-r--r--arch/x86/include/asm/alternative.h73
1 files changed, 48 insertions, 25 deletions
diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index 473bdbee378a..ba32af062f61 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -48,8 +48,9 @@ struct alt_instr {
s32 repl_offset; /* offset to replacement instruction */
u16 cpuid; /* cpuid bit set for replacement */
u8 instrlen; /* length of original instruction */
- u8 replacementlen; /* length of new instruction, <= instrlen */
-};
+ u8 replacementlen; /* length of new instruction */
+ u8 padlen; /* length of build-time padding */
+} __packed;
extern void alternative_instructions(void);
extern void apply_alternatives(struct alt_instr *start, struct alt_instr *end);
@@ -76,50 +77,69 @@ static inline int alternatives_text_reserved(void *start, void *end)
}
#endif /* CONFIG_SMP */
-#define OLDINSTR(oldinstr) "661:\n\t" oldinstr "\n662:\n"
+#define b_replacement(num) "664"#num
+#define e_replacement(num) "665"#num
-#define b_replacement(number) "663"#number
-#define e_replacement(number) "664"#number
+#define alt_end_marker "663"
+#define alt_slen "662b-661b"
+#define alt_pad_len alt_end_marker"b-662b"
+#define alt_total_slen alt_end_marker"b-661b"
+#define alt_rlen(num) e_replacement(num)"f-"b_replacement(num)"f"
-#define alt_slen "662b-661b"
-#define alt_rlen(number) e_replacement(number)"f-"b_replacement(number)"f"
+#define __OLDINSTR(oldinstr, num) \
+ "661:\n\t" oldinstr "\n662:\n" \
+ ".skip -(((" alt_rlen(num) ")-(" alt_slen ")) > 0) * " \
+ "((" alt_rlen(num) ")-(" alt_slen ")),0x90\n"
-#define ALTINSTR_ENTRY(feature, number) \
+#define OLDINSTR(oldinstr, num) \
+ __OLDINSTR(oldinstr, num) \
+ alt_end_marker ":\n"
+
+/*
+ * max without conditionals. Idea adapted from:
+ * http://graphics.stanford.edu/~seander/bithacks.html#IntegerMinOrMax
+ *
+ * The additional "-" is needed because gas works with s32s.
+ */
+#define alt_max_short(a, b) "((" a ") ^ (((" a ") ^ (" b ")) & -(-((" a ") - (" b ")))))"
+
+/*
+ * Pad the second replacement alternative with additional NOPs if it is
+ * additionally longer than the first replacement alternative.
+ */
+#define OLDINSTR_2(oldinstr, num1, num2) \
+ "661:\n\t" oldinstr "\n662:\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"
+
+#define ALTINSTR_ENTRY(feature, num) \
" .long 661b - .\n" /* label */ \
- " .long " b_replacement(number)"f - .\n" /* new instruction */ \
+ " .long " b_replacement(num)"f - .\n" /* new instruction */ \
" .word " __stringify(feature) "\n" /* feature bit */ \
- " .byte " alt_slen "\n" /* source len */ \
- " .byte " alt_rlen(number) "\n" /* replacement len */
-
-#define DISCARD_ENTRY(number) /* rlen <= slen */ \
- " .byte 0xff + (" alt_rlen(number) ") - (" alt_slen ")\n"
+ " .byte " alt_total_slen "\n" /* source len */ \
+ " .byte " alt_rlen(num) "\n" /* replacement len */ \
+ " .byte " alt_pad_len "\n" /* pad len */
-#define ALTINSTR_REPLACEMENT(newinstr, feature, number) /* replacement */ \
- b_replacement(number)":\n\t" newinstr "\n" e_replacement(number) ":\n\t"
+#define ALTINSTR_REPLACEMENT(newinstr, feature, num) /* replacement */ \
+ b_replacement(num)":\n\t" newinstr "\n" e_replacement(num) ":\n\t"
/* alternative assembly primitive: */
#define ALTERNATIVE(oldinstr, newinstr, feature) \
- OLDINSTR(oldinstr) \
+ OLDINSTR(oldinstr, 1) \
".pushsection .altinstructions,\"a\"\n" \
ALTINSTR_ENTRY(feature, 1) \
".popsection\n" \
- ".pushsection .discard,\"aw\",@progbits\n" \
- DISCARD_ENTRY(1) \
- ".popsection\n" \
".pushsection .altinstr_replacement, \"ax\"\n" \
ALTINSTR_REPLACEMENT(newinstr, feature, 1) \
".popsection"
#define ALTERNATIVE_2(oldinstr, newinstr1, feature1, newinstr2, feature2)\
- OLDINSTR(oldinstr) \
+ OLDINSTR_2(oldinstr, 1, 2) \
".pushsection .altinstructions,\"a\"\n" \
ALTINSTR_ENTRY(feature1, 1) \
ALTINSTR_ENTRY(feature2, 2) \
".popsection\n" \
- ".pushsection .discard,\"aw\",@progbits\n" \
- DISCARD_ENTRY(1) \
- DISCARD_ENTRY(2) \
- ".popsection\n" \
".pushsection .altinstr_replacement, \"ax\"\n" \
ALTINSTR_REPLACEMENT(newinstr1, feature1, 1) \
ALTINSTR_REPLACEMENT(newinstr2, feature2, 2) \
@@ -146,6 +166,9 @@ static inline int alternatives_text_reserved(void *start, void *end)
#define alternative(oldinstr, newinstr, feature) \
asm volatile (ALTERNATIVE(oldinstr, newinstr, feature) : : : "memory")
+#define alternative_2(oldinstr, newinstr1, feature1, newinstr2, feature2) \
+ asm volatile(ALTERNATIVE_2(oldinstr, newinstr1, feature1, newinstr2, feature2) ::: "memory")
+
/*
* Alternative inline assembly with input.
*