x86: fix page_is_ram() thinko (156fbc3f) · Commits · 戴 / test

page_is_ram() has a special case for the 640k-1M bios area, however due to a thinko the special case checks the e820 table entry and not the memory the user has asked for. This patch fixes the bug. [ mingo@elte.hu: this too is better solved in the e820 space, but those fixes are too intrusive for v2.6.25. ] Signed-off-by:

Arjan van de Ven <arjan@linux.intel.com> Signed-off-by:

Ingo Molnar <mingo@elte.hu> Signed-off-by:

Thomas Gleixner <tglx@linutronix.de>

arch/x86/mm/ioremap.c

+7 −8

Original line number	Diff line number	Diff line
		@@ -50,6 +50,13 @@ int page_is_ram(unsigned long pagenr)
		if (pagenr == 0)
		return 0;

		/*
		* Second special case: Some BIOSen report the PC BIOS
		* area (640->1Mb) as ram even though it is not.
		*/
		if (pagenr >= (BIOS_BEGIN >> PAGE_SHIFT) &&
		pagenr < (BIOS_END >> PAGE_SHIFT))
		return 0;

		for (i = 0; i < e820.nr_map; i++) {
		/*
		@@ -60,14 +67,6 @@ int page_is_ram(unsigned long pagenr)
		addr = (e820.map[i].addr + PAGE_SIZE-1) >> PAGE_SHIFT;
		end = (e820.map[i].addr + e820.map[i].size) >> PAGE_SHIFT;

		/*
		* Sanity check: Some BIOSen report areas as RAM that
		* are not. Notably the 640->1Mb area, which is the
		* PCI BIOS area.
		*/
		if (addr >= (BIOS_BEGIN >> PAGE_SHIFT) &&
		end < (BIOS_END >> PAGE_SHIFT))
		continue;

		if ((pagenr >= addr) && (pagenr < end))
		return 1;

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