ARM: 8647/2: nommu: dynamic exception base address setting (f8300a0b) · Commits · 戴 / test

arch/arm/mm/nommu.c

+50 −2

Original line number	Diff line number	Diff line
		@@ -11,6 +11,7 @@
		#include <linux/kernel.h>

		#include <asm/cacheflush.h>
		#include <asm/cp15.h>
		#include <asm/sections.h>
		#include <asm/page.h>
		#include <asm/setup.h>
		@@ -22,6 +23,8 @@

		#include "mm.h"

		unsigned long vectors_base;

		#ifdef CONFIG_ARM_MPU
		struct mpu_rgn_info mpu_rgn_info;

		@@ -278,15 +281,60 @@ static void adjust_lowmem_bounds_mpu(void) {}
		static void __init mpu_setup(void) {}
		#endif /* CONFIG_ARM_MPU */

		#ifdef CONFIG_CPU_CP15
		#ifdef CONFIG_CPU_HIGH_VECTOR
		static unsigned long __init setup_vectors_base(void)
		{
		unsigned long reg = get_cr();

		set_cr(reg \| CR_V);
		return 0xffff0000;
		}
		#else /* CONFIG_CPU_HIGH_VECTOR */
		/* Write exception base address to VBAR */
		static inline void set_vbar(unsigned long val)
		{
		asm("mcr p15, 0, %0, c12, c0, 0" : : "r" (val) : "cc");
		}

		/*
		* Security extensions, bits[7:4], permitted values,
		* 0b0000 - not implemented, 0b0001/0b0010 - implemented
		*/
		static inline bool security_extensions_enabled(void)
		{
		return !!cpuid_feature_extract(CPUID_EXT_PFR1, 4);
		}

		static unsigned long __init setup_vectors_base(void)
		{
		unsigned long base = 0, reg = get_cr();

		set_cr(reg & ~CR_V);
		if (security_extensions_enabled()) {
		if (IS_ENABLED(CONFIG_REMAP_VECTORS_TO_RAM))
		base = CONFIG_DRAM_BASE;
		set_vbar(base);
		} else if (IS_ENABLED(CONFIG_REMAP_VECTORS_TO_RAM)) {
		if (CONFIG_DRAM_BASE != 0)
		pr_err("Security extensions not enabled, vectors cannot be remapped to RAM, vectors base will be 0x00000000\n");
		}

		return base;
		}
		#endif /* CONFIG_CPU_HIGH_VECTOR */
		#endif /* CONFIG_CPU_CP15 */

		void __init arm_mm_memblock_reserve(void)
		{
		#ifndef CONFIG_CPU_V7M
		vectors_base = IS_ENABLED(CONFIG_CPU_CP15) ? setup_vectors_base() : 0;
		/*
		* Register the exception vector page.
		* some architectures which the DRAM is the exception vector to trap,
		* alloc_page breaks with error, although it is not NULL, but "0."
		*/
		memblock_reserve(CONFIG_VECTORS_BASE, 2 * PAGE_SIZE);
		memblock_reserve(vectors_base, 2 * PAGE_SIZE);
		#else /* ifndef CONFIG_CPU_V7M */
		/*
		* There is no dedicated vector page on V7-M. So nothing needs to be
		@@ -310,7 +358,7 @@ void __init adjust_lowmem_bounds(void)
		*/
		void __init paging_init(const struct machine_desc *mdesc)
		{
		early_trap_init((void *)CONFIG_VECTORS_BASE);
		early_trap_init((void *)vectors_base);
		mpu_setup();
		bootmem_init();
		}

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