Commit 075f48c9 authored by Mark Rutland's avatar Mark Rutland Committed by Catalin Marinas
Browse files

arm64: Rework setup_cpu_features() 



Currently setup_cpu_features() handles a mixture of one-time kernel
feature setup (e.g. cpucaps) and one-time user feature setup (e.g. ELF
hwcaps). Subsequent patches will rework other one-time setup and expand
the logic currently in setup_cpu_features(), and in preparation for this
it would be helpful to split the kernel and user setup into separate
functions.

This patch splits setup_user_features() out of setup_cpu_features(),
with a few additional cleanups of note:

* setup_cpu_features() is renamed to setup_system_features() to make it
  clear that it handles system-wide feature setup rather than cpu-local
  feature setup.

* setup_system_capabilities() is folded into setup_system_features().

* Presence of TTBR0 pan is logged immediately after
  update_cpu_capabilities(), so that this is guaranteed to appear
  alongside all the other detected system cpucaps.

* The 'cwg' variable is removed as its value is only consumed once and
  it's simpler to use cache_type_cwg() directly without assigning its
  return value to a variable.

* The call to setup_user_features() is moved after alternatives are
  patched, which will allow user feature setup code to depend on
  alternative branches and allow for simplifications in subsequent
  patches.

Signed-off-by: default avatarMark Rutland <mark.rutland@arm.com>
Reviewed-by: default avatarSuzuki K Poulose <suzuki.poulose@arm.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent 7bf46aa1

arch/arm64/include/asm/cpufeature.h

+3 −1
Original line number Diff line number Diff line
@@ -649,7 +649,9 @@ static inline bool id_aa64pfr1_mte(u64 pfr1) 
	return val >= ID_AA64PFR1_EL1_MTE_MTE2;

}



void __init setup_cpu_features(void);

void __init setup_system_features(void);

void __init setup_user_features(void);



void check_local_cpu_capabilities(void);



u64 read_sanitised_ftr_reg(u32 id);

arch/arm64/kernel/cpufeature.c

+21 −22
Original line number Diff line number Diff line
@@ -3328,23 +3328,35 @@ unsigned long cpu_get_elf_hwcap2(void) 
	return elf_hwcap[1];

}



static void __init setup_system_capabilities(void)

void __init setup_system_features(void)

{

	/*

	 * We have finalised the system-wide safe feature

	 * registers, finalise the capabilities that depend

	 * on it. Also enable all the available capabilities,

	 * that are not enabled already.

	 * The system-wide safe feature feature register values have been

	 * finalized. Finalize and log the available system capabilities.

	 */

	update_cpu_capabilities(SCOPE_SYSTEM);

	if (system_uses_ttbr0_pan())

		pr_info("emulated: Privileged Access Never (PAN) using TTBR0_EL1 switching\n");



	/*

	 * Enable all the available capabilities which have not been enabled

	 * already.

	 */

	enable_cpu_capabilities(SCOPE_ALL & ~SCOPE_BOOT_CPU);



	sve_setup();

	sme_setup();



	/*

	 * Check for sane CTR_EL0.CWG value.

	 */

	if (!cache_type_cwg())

		pr_warn("No Cache Writeback Granule information, assuming %d\n",

			ARCH_DMA_MINALIGN);

}



void __init setup_cpu_features(void)

void __init setup_user_features(void)

{

	u32 cwg;



	setup_system_capabilities();

	setup_elf_hwcaps(arm64_elf_hwcaps);



	if (system_supports_32bit_el0()) {
@@ -3352,20 +3364,7 @@ void __init setup_cpu_features(void) 
		elf_hwcap_fixup();

	}



	if (system_uses_ttbr0_pan())

		pr_info("emulated: Privileged Access Never (PAN) using TTBR0_EL1 switching\n");



	sve_setup();

	sme_setup();

	minsigstksz_setup();



	/*

	 * Check for sane CTR_EL0.CWG value.

	 */

	cwg = cache_type_cwg();

	if (!cwg)

		pr_warn("No Cache Writeback Granule information, assuming %d\n",

			ARCH_DMA_MINALIGN);

}



static int enable_mismatched_32bit_el0(unsigned int cpu)

arch/arm64/kernel/smp.c

+2 −1
Original line number Diff line number Diff line
@@ -431,9 +431,10 @@ static void __init hyp_mode_check(void) 
void __init smp_cpus_done(unsigned int max_cpus)

{

	pr_info("SMP: Total of %d processors activated.\n", num_online_cpus());

	setup_cpu_features();

	setup_system_features();

	hyp_mode_check();

	apply_alternatives_all();

	setup_user_features();

	mark_linear_text_alias_ro();

}