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x86/idle: Remove CONFIG_AS_TPAUSE

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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: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Ingo 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
This commit is contained in:
Uros Bizjak 2025-04-02 20:08:08 +02:00 committed by Ingo Molnar
parent 19c3dcd953
commit a72d55dc3b
2 changed files with 2 additions and 13 deletions
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4
arch/x86/Kconfig.assembler
View File

@ -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)

11
arch/x86/include/asm/mwait.h
View File

@ -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 */