metag: add boot time LNKGET/LNKSET check (883a6355) · Commits · 戴 / test

arch/metag/mm/cache.c

+79 −0

Original line number	Diff line number	Diff line
		@@ -14,6 +14,7 @@
		#include <linux/io.h>
		#include <asm/cacheflush.h>
		#include <asm/core_reg.h>
		#include <asm/global_lock.h>
		#include <asm/metag_isa.h>
		#include <asm/metag_mem.h>
		#include <asm/metag_regs.h>
		@@ -36,6 +37,82 @@ static int icache_set_shift = METAG_TBI_CACHE_SIZE_BASE_LOG2
		static unsigned char dcache_sets_log2 = DEFAULT_CACHE_WAYS_LOG2;
		static unsigned char icache_sets_log2 = DEFAULT_CACHE_WAYS_LOG2;

		#ifndef CONFIG_METAG_META12
		/**
		* metag_lnkget_probe() - Probe whether lnkget/lnkset go around the cache
		*/
		static volatile u32 lnkget_testdata[16] __initdata __aligned(64);

		#define LNKGET_CONSTANT 0xdeadbeef

		void __init metag_lnkget_probe(void)
		{
		int temp;
		long flags;

		/*
		* It's conceivable the user has configured a globally coherent cache
		* shared with non-Linux hardware threads, so use LOCK2 to prevent them
		* from executing and causing cache eviction during the test.
		*/
		__global_lock2(flags);

		/* read a value to bring it into the cache */
		(void)lnkget_testdata[0];
		lnkget_testdata[0] = 0;

		/* lnkget/lnkset it to modify it */
		asm volatile(
		"1: LNKGETD %0, [%1]\n"
		" LNKSETD [%1], %2\n"
		" DEFR %0, TXSTAT\n"
		" ANDT %0, %0, #HI(0x3f000000)\n"
		" CMPT %0, #HI(0x02000000)\n"
		" BNZ 1b\n"
		: "=&d" (temp)
		: "da" (&lnkget_testdata[0]), "bd" (LNKGET_CONSTANT)
		: "cc");

		/* re-read it to see if the cached value changed */
		temp = lnkget_testdata[0];

		__global_unlock2(flags);

		/* flush the cache line to fix any incoherency */
		__builtin_dcache_flush((void *)&lnkget_testdata[0]);

		#if defined(CONFIG_METAG_LNKGET_AROUND_CACHE)
		/* if the cache is right, LNKGET_AROUND_CACHE is unnecessary */
		if (temp == LNKGET_CONSTANT)
		pr_info("LNKGET/SET go through cache but CONFIG_METAG_LNKGET_AROUND_CACHE=y\n");
		#elif defined(CONFIG_METAG_ATOMICITY_LNKGET)
		/*
		* if the cache is wrong, LNKGET_AROUND_CACHE is really necessary
		* because the kernel is configured to use LNKGET/SET for atomicity
		*/
		WARN(temp != LNKGET_CONSTANT,
		"LNKGET/SET go around cache but CONFIG_METAG_LNKGET_AROUND_CACHE=n\n"
		"Expect kernel failure as it's used for atomicity primitives\n");
		#elif defined(CONFIG_SMP)
		/*
		* if the cache is wrong, LNKGET_AROUND_CACHE should be used or the
		* gateway page won't flush and userland could break.
		*/
		WARN(temp != LNKGET_CONSTANT,
		"LNKGET/SET go around cache but CONFIG_METAG_LNKGET_AROUND_CACHE=n\n"
		"Expect userland failure as it's used for user gateway page\n");
		#else
		/*
		* if the cache is wrong, LNKGET_AROUND_CACHE is set wrong, but it
		* doesn't actually matter as it doesn't have any effect on !SMP &&
		* !ATOMICITY_LNKGET.
		*/
		if (temp != LNKGET_CONSTANT)
		pr_warn("LNKGET/SET go around cache but CONFIG_METAG_LNKGET_AROUND_CACHE=n\n");
		#endif
		}
		#endif /* !CONFIG_METAG_META12 */

		/**
		* metag_cache_probe() - Probe L1 cache configuration.
		*
		@@ -68,6 +145,8 @@ void __init metag_cache_probe(void)
		dcache_set_shift += (config & METAC_CORECFG2_DCSZ_BITS)
		>> METAC_CORECFG2_DCSZ_S;
		dcache_set_shift -= dcache_sets_log2;

		metag_lnkget_probe();
		#else
		/* Extract cache sizes from global heap segment */
		unsigned long val, u;

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