powerpc/64s: Add dt_cpu_ftrs boot time setup option (a2b05b7a) · Commits · 戴 / test

Documentation/admin-guide/kernel-parameters.txt

+9 −0

Original line number	Diff line number	Diff line
		@@ -866,6 +866,15 @@

		dscc4.setup= [NET]

		dt_cpu_ftrs= [PPC]
		Format: {"off" \| "known"}
		Control how the dt_cpu_ftrs device-tree binding is
		used for CPU feature discovery and setup (if it
		exists).
		off: Do not use it, fall back to legacy cpu table.
		known: Do not pass through unknown features to guests
		or userspace, only those that the kernel is aware of.

		dump_apple_properties [X86]
		Dump name and content of EFI device properties on
		x86 Macs. Useful for driver authors to determine

arch/powerpc/Kconfig

+0 −5

Original line number	Diff line number	Diff line
		@@ -391,11 +391,6 @@ config PPC_DT_CPU_FTRS
		firmware provides this binding.
		If you're not sure say Y.

		config PPC_CPUFEATURES_ENABLE_UNKNOWN
		bool "cpufeatures pass through unknown features to guest/userspace"
		depends on PPC_DT_CPU_FTRS
		default y

		config HIGHMEM
		bool "High memory support"
		depends on PPC32

arch/powerpc/kernel/dt_cpu_ftrs.c

+48 −9

Original line number	Diff line number	Diff line
		@@ -8,6 +8,7 @@
		#include <linux/export.h>
		#include <linux/init.h>
		#include <linux/jump_label.h>
		#include <linux/libfdt.h>
		#include <linux/memblock.h>
		#include <linux/printk.h>
		#include <linux/sched.h>
		@@ -671,12 +672,24 @@ static struct dt_cpu_feature_match __initdata
		{"wait-v3", feat_enable, 0},
		};

		/* XXX: how to configure this? Default + boot time? */
		#ifdef CONFIG_PPC_CPUFEATURES_ENABLE_UNKNOWN
		#define CPU_FEATURE_ENABLE_UNKNOWN 1
		#else
		#define CPU_FEATURE_ENABLE_UNKNOWN 0
		#endif
		static bool __initdata using_dt_cpu_ftrs;
		static bool __initdata enable_unknown = true;

		static int __init dt_cpu_ftrs_parse(char *str)
		{
		if (!str)
		return 0;

		if (!strcmp(str, "off"))
		using_dt_cpu_ftrs = false;
		else if (!strcmp(str, "known"))
		enable_unknown = false;
		else
		return 1;

		return 0;
		}
		early_param("dt_cpu_ftrs", dt_cpu_ftrs_parse);

		static void __init cpufeatures_setup_start(u32 isa)
		{
		@@ -707,7 +720,7 @@ static bool __init cpufeatures_process_feature(struct dt_cpu_feature *f)
		}
		}

		if (!known && CPU_FEATURE_ENABLE_UNKNOWN) {
		if (!known && enable_unknown) {
		if (!feat_try_enable_unknown(f)) {
		pr_info("not enabling: %s (unknown and unsupported by kernel)\n",
		f->name);
		@@ -756,6 +769,26 @@ static void __init cpufeatures_setup_finished(void)
		cur_cpu_spec->cpu_features, cur_cpu_spec->mmu_features);
		}

		static int __init disabled_on_cmdline(void)
		{
		unsigned long root, chosen;
		const char *p;

		root = of_get_flat_dt_root();
		chosen = of_get_flat_dt_subnode_by_name(root, "chosen");
		if (chosen == -FDT_ERR_NOTFOUND)
		return false;

		p = of_get_flat_dt_prop(chosen, "bootargs", NULL);
		if (!p)
		return false;

		if (strstr(p, "dt_cpu_ftrs=off"))
		return true;

		return false;
		}

		static int __init fdt_find_cpu_features(unsigned long node, const char *uname,
		int depth, void *data)
		{
		@@ -766,8 +799,6 @@ static int __init fdt_find_cpu_features(unsigned long node, const char *uname,
		return 0;
		}

		static bool __initdata using_dt_cpu_ftrs = false;

		bool __init dt_cpu_ftrs_in_use(void)
		{
		return using_dt_cpu_ftrs;
		@@ -775,6 +806,8 @@ bool __init dt_cpu_ftrs_in_use(void)

		bool __init dt_cpu_ftrs_init(void *fdt)
		{
		using_dt_cpu_ftrs = false;

		/* Setup and verify the FDT, if it fails we just bail */
		if (!early_init_dt_verify(fdt))
		return false;
		@@ -782,6 +815,9 @@ bool __init dt_cpu_ftrs_init(void *fdt)
		if (!of_scan_flat_dt(fdt_find_cpu_features, NULL))
		return false;

		if (disabled_on_cmdline())
		return false;

		cpufeatures_setup_cpu();

		using_dt_cpu_ftrs = true;
		@@ -1027,5 +1063,8 @@ static int __init dt_cpu_ftrs_scan_callback(unsigned long node, const char

		void __init dt_cpu_ftrs_scan(void)
		{
		if (!using_dt_cpu_ftrs)
		return;

		of_scan_flat_dt(dt_cpu_ftrs_scan_callback, NULL);
		}

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