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Commit 94af3abf authored by Rusty Russell's avatar Rusty Russell Committed by Benjamin Herrenschmidt
Browse files

powerpc: ELF2 binaries launched directly. 



No function descriptor, but we set r12 up and set TIF_RESTOREALL as it
normally isn't restored on return from syscall.

Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
Signed-off-by: default avatarAnton Blanchard <anton@samba.org>
Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent 918d0355

arch/powerpc/kernel/process.c

+35 −15
Original line number Diff line number Diff line
@@ -1086,12 +1086,31 @@ void start_thread(struct pt_regs *regs, unsigned long start, unsigned long sp) 
	regs->msr = MSR_USER;

#else

	if (!is_32bit_task()) {

		unsigned long entry, toc;

		unsigned long entry;



		/* start is a relocated pointer to the function descriptor for

		 * the elf _start routine.  The first entry in the function

		 * descriptor is the entry address of _start and the second

		 * entry is the TOC value we need to use.

		if (is_elf2_task()) {

			/* Look ma, no function descriptors! */

			entry = start;



			/*

			 * Ulrich says:

			 *   The latest iteration of the ABI requires that when

			 *   calling a function (at its global entry point),

			 *   the caller must ensure r12 holds the entry point

			 *   address (so that the function can quickly

			 *   establish addressability).

			 */

			regs->gpr[12] = start;

			/* Make sure that's restored on entry to userspace. */

			set_thread_flag(TIF_RESTOREALL);

		} else {

			unsigned long toc;



			/* start is a relocated pointer to the function

			 * descriptor for the elf _start routine.  The first

			 * entry in the function descriptor is the entry

			 * address of _start and the second entry is the TOC

			 * value we need to use.

			 */

			__get_user(entry, (unsigned long __user *)start);

			__get_user(toc, (unsigned long __user *)start+1);
@@ -1103,8 +1122,9 @@ void start_thread(struct pt_regs *regs, unsigned long start, unsigned long sp) 
				entry += load_addr;

				toc   += load_addr;

			}

		regs->nip = entry;

			regs->gpr[2] = toc;

		}

		regs->nip = entry;

		regs->msr = MSR_USER64;

	} else {

		regs->nip = start;