Commit 866ba633 authored by Keith Owens's avatar Keith Owens Committed by Tony Luck
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[IA64] Module gp must point to valid memory 



Some bits of the kernel assume that gp always points to valid memory,
in particular PHYSICAL_MODE_ENTER() assumes that both gp and sp are
valid virtual addresses with associated physical pages.  The IA64
module loader puts gp well past the end of the module, with no physical
backing.  Offsets on gp are still valid, but physical mode addressing
breaks for modules.  Ensure that gp always falls within the module
body.  Also ensure that gp is 8 byte aligned.

Signed-off-by: default avatarKeith Owens <kaos@sgi.com>
Signed-off-by: default avatarTony Luck <tony.luck@intel.com>
parent ad597bd5

arch/ia64/kernel/module.c

+6 −4
Original line number Diff line number Diff line
@@ -825,14 +825,16 @@ apply_relocate_add (Elf64_Shdr *sechdrs, const char *strtab, unsigned int symind 
		 * XXX Should have an arch-hook for running this after final section

		 *     addresses have been selected...

		 */

		/* See if gp can cover the entire core module:  */

		uint64_t gp = (uint64_t) mod->module_core + MAX_LTOFF / 2;

		if (mod->core_size >= MAX_LTOFF)

		uint64_t gp;

		if (mod->core_size > MAX_LTOFF)

			/*

			 * This takes advantage of fact that SHF_ARCH_SMALL gets allocated

			 * at the end of the module.

			 */

			gp = (uint64_t) mod->module_core + mod->core_size - MAX_LTOFF / 2;

			gp = mod->core_size - MAX_LTOFF / 2;

		else

			gp = mod->core_size / 2;

		gp = (uint64_t) mod->module_core + ((gp + 7) & -8);

		mod->arch.gp = gp;

		DEBUGP("%s: placing gp at 0x%lx\n", __FUNCTION__, gp);

	}