Commit a72d55dc authored by Uros Bizjak's avatar Uros Bizjak Committed by Ingo Molnar
Browse files

x86/idle: Remove CONFIG_AS_TPAUSE 



There is not much point in CONFIG_AS_TPAUSE at all when the emitted
assembly is always the same - it only obfuscates the __tpause() code
in essence.

Remove the TPAUSE insn mnemonic from __tpause() and leave only
the equivalent byte-wise definition. This can then be changed
back to insn mnemonic once binutils 2.31.1 is the minimum version
to build the kernel. (Right now it's 2.25.)

Signed-off-by: default avatarUros Bizjak <ubizjak@gmail.com>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20250402180827.3762-4-ubizjak@gmail.com
parent 19c3dcd9

arch/x86/Kconfig.assembler

+0 −4
Original line number Diff line number Diff line
@@ -15,10 +15,6 @@ config AS_SHA256_NI 
	def_bool $(as-instr,sha256msg1 %xmm0$(comma)%xmm1)

	help

	  Supported by binutils >= 2.24 and LLVM integrated assembler

config AS_TPAUSE

	def_bool $(as-instr,tpause %ecx)

	help

	  Supported by binutils >= 2.31.1 and LLVM integrated assembler >= V7



config AS_GFNI

	def_bool $(as-instr,vgf2p8mulb %xmm0$(comma)%xmm1$(comma)%xmm2)

arch/x86/include/asm/mwait.h

+2 −9
Original line number Diff line number Diff line
@@ -138,16 +138,9 @@ static __always_inline void mwait_idle_with_hints(unsigned long eax, unsigned lo 
 */

static inline void __tpause(u32 ecx, u32 edx, u32 eax)

{

	/* "tpause %ecx, %edx, %eax" */

	#ifdef CONFIG_AS_TPAUSE

	asm volatile("tpause %%ecx"

		     :

		     : "c"(ecx), "d"(edx), "a"(eax));

	#else

	/* "tpause %ecx" */

	asm volatile(".byte 0x66, 0x0f, 0xae, 0xf1"

		     :

		     : "c"(ecx), "d"(edx), "a"(eax));

	#endif

		     :: "c" (ecx), "d" (edx), "a" (eax));

}



#endif /* _ASM_X86_MWAIT_H */