ARM: hwcap: disable HWCAP_SWP if the CPU advertises it has exclusives (58171bf2) · Commits · 戴 / test

arch/arm/kernel/setup.c

+22 −7

Original line number	Diff line number	Diff line
		@@ -393,19 +393,34 @@ static void __init cpuid_init_hwcaps(void)
		elf_hwcap \|= HWCAP_LPAE;
		}

		static void __init feat_v6_fixup(void)
		static void __init elf_hwcap_fixup(void)
		{
		int id = read_cpuid_id();

		if ((id & 0xff0f0000) != 0x41070000)
		return;
		unsigned id = read_cpuid_id();
		unsigned sync_prim;

		/*
		* HWCAP_TLS is available only on 1136 r1p0 and later,
		* see also kuser_get_tls_init.
		*/
		if ((((id >> 4) & 0xfff) == 0xb36) && (((id >> 20) & 3) == 0))
		if (read_cpuid_part() == ARM_CPU_PART_ARM1136 &&
		((id >> 20) & 3) == 0) {
		elf_hwcap &= ~HWCAP_TLS;
		return;
		}

		/* Verify if CPUID scheme is implemented */
		if ((id & 0x000f0000) != 0x000f0000)
		return;

		/*
		* If the CPU supports LDREX/STREX and LDREXB/STREXB,
		* avoid advertising SWP; it may not be atomic with
		* multiprocessing cores.
		*/
		sync_prim = ((read_cpuid_ext(CPUID_EXT_ISAR3) >> 8) & 0xf0) \|
		((read_cpuid_ext(CPUID_EXT_ISAR4) >> 20) & 0x0f);
		if (sync_prim >= 0x13)
		elf_hwcap &= ~HWCAP_SWP;
		}

		/*
		@@ -609,7 +624,7 @@ static void __init setup_processor(void)
		#endif
		erratum_a15_798181_init();

		feat_v6_fixup();
		elf_hwcap_fixup();

		cacheid_init();
		cpu_init();