linux-kernel - [PATCH 5.10 014/130] x86/alternative: Use ALTERNATIVE_TERNARY() in _static_cpu

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Message-Id: <20220712183247.060887637@linuxfoundation.org>
Date:   Tue, 12 Jul 2022 20:37:40 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Juergen Gross <jgross@...e.com>,
        Borislav Petkov <bp@...e.de>,
        Ben Hutchings <ben@...adent.org.uk>
Subject: [PATCH 5.10 014/130] x86/alternative: Use ALTERNATIVE_TERNARY() in _static_cpu_has()

From: Juergen Gross <jgross@...e.com>

commit 2fe2a2c7a97c9bc32acc79154b75e754280f7867 upstream.

_static_cpu_has() contains a completely open coded version of
ALTERNATIVE_TERNARY(). Replace that with the macro instead.

Signed-off-by: Juergen Gross <jgross@...e.com>
Signed-off-by: Borislav Petkov <bp@...e.de>
Link: https://lkml.kernel.org/r/20210311142319.4723-8-jgross@suse.com
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 arch/x86/include/asm/cpufeature.h |   41 ++++++++------------------------------
 1 file changed, 9 insertions(+), 32 deletions(-)

--- a/arch/x86/include/asm/cpufeature.h
+++ b/arch/x86/include/asm/cpufeature.h
@@ -8,6 +8,7 @@
 
 #include <asm/asm.h>
 #include <linux/bitops.h>
+#include <asm/alternative.h>
 
 enum cpuid_leafs
 {
@@ -172,39 +173,15 @@ extern void clear_cpu_cap(struct cpuinfo
  */
 static __always_inline bool _static_cpu_has(u16 bit)
 {
-	asm_volatile_goto("1: jmp 6f\n"
-		 "2:\n"
-		 ".skip -(((5f-4f) - (2b-1b)) > 0) * "
-			 "((5f-4f) - (2b-1b)),0x90\n"
-		 "3:\n"
-		 ".section .altinstructions,\"a\"\n"
-		 " .long 1b - .\n"		/* src offset */
-		 " .long 4f - .\n"		/* repl offset */
-		 " .word %P[always]\n"		/* always replace */
-		 " .byte 3b - 1b\n"		/* src len */
-		 " .byte 5f - 4f\n"		/* repl len */
-		 " .byte 3b - 2b\n"		/* pad len */
-		 ".previous\n"
-		 ".section .altinstr_replacement,\"ax\"\n"
-		 "4: jmp %l[t_no]\n"
-		 "5:\n"
-		 ".previous\n"
-		 ".section .altinstructions,\"a\"\n"
-		 " .long 1b - .\n"		/* src offset */
-		 " .long 0\n"			/* no replacement */
-		 " .word %P[feature]\n"		/* feature bit */
-		 " .byte 3b - 1b\n"		/* src len */
-		 " .byte 0\n"			/* repl len */
-		 " .byte 0\n"			/* pad len */
-		 ".previous\n"
-		 ".section .altinstr_aux,\"ax\"\n"
-		 "6:\n"
-		 " testb %[bitnum],%[cap_byte]\n"
-		 " jnz %l[t_yes]\n"
-		 " jmp %l[t_no]\n"
-		 ".previous\n"
+	asm_volatile_goto(
+		ALTERNATIVE_TERNARY("jmp 6f", %P[feature], "", "jmp %l[t_no]")
+		".section .altinstr_aux,\"ax\"\n"
+		"6:\n"
+		" testb %[bitnum],%[cap_byte]\n"
+		" jnz %l[t_yes]\n"
+		" jmp %l[t_no]\n"
+		".previous\n"
 		 : : [feature]  "i" (bit),
-		     [always]   "i" (X86_FEATURE_ALWAYS),
 		     [bitnum]   "i" (1 << (bit & 7)),
 		     [cap_byte] "m" (((const char *)boot_cpu_data.x86_capability)[bit >> 3])
 		 : : t_yes, t_no);