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powerpc: ELF2 binaries launched directly.

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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: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This commit is contained in:
Rusty Russell 2013-11-20 22:15:02 +11:00 committed by Benjamin Herrenschmidt
parent 918d03552e
commit 94af3abf99
1 changed files with 35 additions and 15 deletions
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50
arch/powerpc/kernel/process.c
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@ -1086,25 +1086,45 @@ 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.
*/
__get_user(entry, (unsigned long __user *)start);
__get_user(toc, (unsigned long __user *)start+1);
if (is_elf2_task()) {
/* Look ma, no function descriptors! */
entry = start;
/* Check whether the e_entry function descriptor entries
* need to be relocated before we can use them.
*/
if (load_addr != 0) {
entry += load_addr;
toc += load_addr;
/*
* 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);
/* Check whether the e_entry function descriptor entries
* need to be relocated before we can use them.
*/
if (load_addr != 0) {
entry += load_addr;
toc += load_addr;
}
regs->gpr[2] = toc;
}
regs->nip = entry;
regs->gpr[2] = toc;
regs->msr = MSR_USER64;
} else {
regs->nip = start;