x86/KASLR: Handle the memory limit specified by the 'memmap=' and 'mem=' boot options (4cdba14f) · Commits · 戴 / test

arch/x86/boot/compressed/kaslr.c

+50 −18

Original line number	Diff line number	Diff line
		@@ -88,6 +88,10 @@ struct mem_vector {
		static bool memmap_too_large;


		/* Store memory limit specified by "mem=nn[KMG]" or "memmap=nn[KMG]" */
		unsigned long long mem_limit = ULLONG_MAX;


		enum mem_avoid_index {
		MEM_AVOID_ZO_RANGE = 0,
		MEM_AVOID_INITRD,
		@@ -138,16 +142,23 @@ parse_memmap(char p, unsigned long long start, unsigned long long *size)
		return -EINVAL;

		switch (*p) {
		case '@':
		/* Skip this region, usable */
		*start = 0;
		*size = 0;
		return 0;
		case '#':
		case '$':
		case '!':
		*start = memparse(p + 1, &p);
		return 0;
		case '@':
		/* memmap=nn@ss specifies usable region, should be skipped */
		*size = 0;
		/* Fall through */
		default:
		/*
		* If w/o offset, only size specified, memmap=nn[KMG] has the
		* same behaviour as mem=nn[KMG]. It limits the max address
		* system can use. Region above the limit should be avoided.
		*/
		*start = 0;
		return 0;
		}

		return -EINVAL;
		@@ -173,9 +184,14 @@ static void mem_avoid_memmap(char *str)
		if (rc < 0)
		break;
		str = k;
		/* A usable region that should not be skipped */
		if (size == 0)

		if (start == 0) {
		/* Store the specified memory limit if size > 0 */
		if (size > 0)
		mem_limit = size;

		continue;
		}

		mem_avoid[MEM_AVOID_MEMMAP_BEGIN + i].start = start;
		mem_avoid[MEM_AVOID_MEMMAP_BEGIN + i].size = size;
		@@ -187,19 +203,15 @@ static void mem_avoid_memmap(char *str)
		memmap_too_large = true;
		}


		/*
		* handle_mem_memmap will also cover 'mem=' issue in next patch. Will remove
		* this note later.
		*/
		static int handle_mem_memmap(void)
		{
		char args = (char )get_cmd_line_ptr();
		size_t len = strlen((char *)args);
		char *tmp_cmdline;
		char param, val;
		u64 mem_size;

		if (!strstr(args, "memmap="))
		if (!strstr(args, "memmap=") && !strstr(args, "mem="))
		return 0;

		tmp_cmdline = malloc(len + 1);
		@@ -222,8 +234,20 @@ static int handle_mem_memmap(void)
		return -1;
		}

		if (!strcmp(param, "memmap"))
		if (!strcmp(param, "memmap")) {
		mem_avoid_memmap(val);
		} else if (!strcmp(param, "mem")) {
		char *p = val;

		if (!strcmp(p, "nopentium"))
		continue;
		mem_size = memparse(p, &p);
		if (mem_size == 0) {
		free(tmp_cmdline);
		return -EINVAL;
		}
		mem_limit = mem_size;
		}
		}

		free(tmp_cmdline);
		@@ -460,7 +484,8 @@ static void process_e820_entry(struct boot_e820_entry *entry,
		{
		struct mem_vector region, overlap;
		struct slot_area slot_area;
		unsigned long start_orig;
		unsigned long start_orig, end;
		struct boot_e820_entry cur_entry;

		/* Skip non-RAM entries. */
		if (entry->type != E820_TYPE_RAM)
		@@ -474,8 +499,15 @@ static void process_e820_entry(struct boot_e820_entry *entry,
		if (entry->addr + entry->size < minimum)
		return;

		region.start = entry->addr;
		region.size = entry->size;
		/* Ignore entries above memory limit */
		end = min(entry->size + entry->addr, mem_limit);
		if (entry->addr >= end)
		return;
		cur_entry.addr = entry->addr;
		cur_entry.size = end - entry->addr;

		region.start = cur_entry.addr;
		region.size = cur_entry.size;

		/* Give up if slot area array is full. */
		while (slot_area_index < MAX_SLOT_AREA) {
		@@ -489,7 +521,7 @@ static void process_e820_entry(struct boot_e820_entry *entry,
		region.start = ALIGN(region.start, CONFIG_PHYSICAL_ALIGN);

		/* Did we raise the address above this e820 region? */
		if (region.start > entry->addr + entry->size)
		if (region.start > cur_entry.addr + cur_entry.size)
		return;

		/* Reduce size by any delta from the original address. */

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