Merge branch 'x86-alternatives-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip (6ea98b4b) · Commits · 戴 / test

arch/x86/include/asm/alternative.h

+32 −7

Original line number	Diff line number	Diff line
		@@ -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"

		/*
		@@ -116,11 +115,23 @@ 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"

		#define OLDINSTR_3(oldinsn, n1, n2, n3) \
		"# ALT: oldinstr3\n" \
		"661:\n\t" oldinsn "\n662:\n" \
		"# ALT: padding3\n" \
		".skip -((" alt_max_short(alt_max_short(alt_rlen(n1), alt_rlen(n2)), alt_rlen(n3)) \
		" - (" alt_slen ")) > 0) * " \
		"(" alt_max_short(alt_max_short(alt_rlen(n1), alt_rlen(n2)), alt_rlen(n3)) \
		" - (" alt_slen ")), 0x90\n" \
		alt_end_marker ":\n"

		#define ALTINSTR_ENTRY(feature, num) \
		" .long 661b - .\n" /* label */ \
		" .long " b_replacement(num)"f - .\n" /* new instruction */ \
		@@ -130,7 +141,8 @@ static inline int alternatives_text_reserved(void start, void end)
		" .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"
		"# ALT: replacement " #num "\n" \
		b_replacement(num)":\n\t" newinstr "\n" e_replacement(num) ":\n"

		/* alternative assembly primitive: */
		#define ALTERNATIVE(oldinstr, newinstr, feature) \
		@@ -153,6 +165,19 @@ static inline int alternatives_text_reserved(void start, void end)
		ALTINSTR_REPLACEMENT(newinstr2, feature2, 2) \
		".popsection\n"

		#define ALTERNATIVE_3(oldinsn, newinsn1, feat1, newinsn2, feat2, newinsn3, feat3) \
		OLDINSTR_3(oldinsn, 1, 2, 3) \
		".pushsection .altinstructions,\"a\"\n" \
		ALTINSTR_ENTRY(feat1, 1) \
		ALTINSTR_ENTRY(feat2, 2) \
		ALTINSTR_ENTRY(feat3, 3) \
		".popsection\n" \
		".pushsection .altinstr_replacement, \"ax\"\n" \
		ALTINSTR_REPLACEMENT(newinsn1, feat1, 1) \
		ALTINSTR_REPLACEMENT(newinsn2, feat2, 2) \
		ALTINSTR_REPLACEMENT(newinsn3, feat3, 3) \
		".popsection\n"

		/*
		* Alternative instructions for different CPU types or capabilities.
		*

arch/x86/include/asm/msr.h

+14 −2

Original line number	Diff line number	Diff line
		@@ -217,6 +217,8 @@ static __always_inline unsigned long long rdtsc(void)
		*/
		static __always_inline unsigned long long rdtsc_ordered(void)
		{
		DECLARE_ARGS(val, low, high);

		/*
		* The RDTSC instruction is not ordered relative to memory
		* access. The Intel SDM and the AMD APM are both vague on this
		@@ -227,9 +229,19 @@ static __always_inline unsigned long long rdtsc_ordered(void)
		* ordering guarantees as reading from a global memory location
		* that some other imaginary CPU is updating continuously with a
		* time stamp.
		*
		* Thus, use the preferred barrier on the respective CPU, aiming for
		* RDTSCP as the default.
		*/
		barrier_nospec();
		return rdtsc();
		asm volatile(ALTERNATIVE_3("rdtsc",
		"mfence; rdtsc", X86_FEATURE_MFENCE_RDTSC,
		"lfence; rdtsc", X86_FEATURE_LFENCE_RDTSC,
		"rdtscp", X86_FEATURE_RDTSCP)
		: EAX_EDX_RET(val, low, high)
		/* RDTSCP clobbers ECX with MSR_TSC_AUX. */
		:: "ecx");

		return EAX_EDX_VAL(val, low, high);
		}

		static inline unsigned long long native_read_pmc(int counter)

arch/x86/kernel/alternative.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -394,10 +394,10 @@ void __init_or_module noinline apply_alternatives(struct alt_instr *start,
		continue;
		}

		DPRINTK("feat: %d*32+%d, old: (%px len: %d), repl: (%px, len: %d), pad: %d",
		DPRINTK("feat: %d*32+%d, old: (%pS (%px) len: %d), repl: (%px, len: %d), pad: %d",
		a->cpuid >> 5,
		a->cpuid & 0x1f,
		instr, a->instrlen,
		instr, instr, a->instrlen,
		replacement, a->replacementlen, a->padlen);

		DUMP_BYTES(instr, a->instrlen, "%px: old_insn: ", instr);

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