linux-stable/arch/tile/kernel
Chris Metcalf 81711cee93 arch/tile: handle rt_sigreturn() more cleanly
The current tile rt_sigreturn() syscall pattern uses the common idiom
of loading up pt_regs with all the saved registers from the time of
the signal, then anticipating the fact that we will clobber the ABI
"return value" register (r0) as we return from the syscall by setting
the rt_sigreturn return value to whatever random value was in the pt_regs
for r0.

However, this breaks in our 64-bit kernel when running "compat" tasks,
since we always sign-extend the "return value" register to properly
handle returned pointers that are in the upper 2GB of the 32-bit compat
address space.  Doing this to the sigreturn path then causes occasional
random corruption of the 64-bit r0 register.

Instead, we stop doing the crazy "load the return-value register"
hack in sigreturn.  We already have some sigreturn-specific assembly
code that we use to pass the pt_regs pointer to C code.  We extend that
code to also set the link register to point to a spot a few instructions
after the usual syscall return address so we don't clobber the saved r0.
Now it no longer matters what the rt_sigreturn syscall returns, and the
pt_regs structure can be cleanly and completely reloaded.

Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2010-12-17 16:59:29 -05:00
..
asm-offsets.c arch/tile: core support for Tilera 32-bit chips. 2010-06-04 17:11:18 -04:00
backtrace.c arch/tile: support new info op generated by compiler 2010-10-15 15:39:25 -04:00
compat.c BKL: remove extraneous #include <smp_lock.h> 2010-11-17 08:59:32 -08:00
compat_signal.c arch/tile: handle rt_sigreturn() more cleanly 2010-12-17 16:59:29 -05:00
early_printk.c arch/tile: bomb raw_local_irq_ to arch_local_irq_ 2010-11-01 15:30:42 -04:00
entry.S arch/tile: parameterize system PLs to support KVM port 2010-10-15 15:38:09 -04:00
hardwall.c arch/tile: mark "hardwall" device as non-seekable 2010-11-01 15:31:42 -04:00
head_32.S arch/tile: parameterize system PLs to support KVM port 2010-10-15 15:38:09 -04:00
hvglue.lds arch/tile: Enable more sophisticated IRQ model for 32-bit chips. 2010-07-06 13:34:01 -04:00
init_task.c arch/tile: core support for Tilera 32-bit chips. 2010-06-04 17:11:18 -04:00
intvec_32.S arch/tile: handle rt_sigreturn() more cleanly 2010-12-17 16:59:29 -05:00
irq.c arch/tile: bomb raw_local_irq_ to arch_local_irq_ 2010-11-01 15:30:42 -04:00
machine_kexec.c arch/tile: complete migration to new kmap_atomic scheme 2010-11-01 15:30:36 -04:00
Makefile pci root complex: support for tile architecture 2010-11-24 13:13:49 -05:00
messaging.c arch/tile: bomb raw_local_irq_ to arch_local_irq_ 2010-11-01 15:30:42 -04:00
module.c arch/tile: Miscellaneous cleanup changes. 2010-07-06 13:41:51 -04:00
pci-dma.c arch/tile: Do not use GFP_KERNEL for dma_alloc_coherent(). 2010-06-05 10:26:55 -04:00
pci.c pci root complex: support for tile architecture 2010-11-24 13:13:49 -05:00
proc.c arch: tile: kernel/proc.c Removed duplicated #include 2010-08-13 08:10:16 -04:00
process.c arch/tile: handle CLONE_SETTLS in copy_thread(), not user space 2010-12-17 16:56:50 -05:00
ptrace.c arch/tile: don't allow user code to set the PL via ptrace or signal return 2010-11-01 15:31:17 -04:00
reboot.c arch/tile: bomb raw_local_irq_ to arch_local_irq_ 2010-11-01 15:30:42 -04:00
regs_32.S arch/tile: parameterize system PLs to support KVM port 2010-10-15 15:38:09 -04:00
relocate_kernel.S arch/tile: core support for Tilera 32-bit chips. 2010-06-04 17:11:18 -04:00
setup.c arch/tile: make glibc's sysconf(_SC_NPROCESSORS_CONF) work correctly 2010-11-24 13:42:15 -05:00
signal.c arch/tile: handle rt_sigreturn() more cleanly 2010-12-17 16:59:29 -05:00
single_step.c arch/tile: enable single-step support for TILE-Gx 2010-10-15 15:38:26 -04:00
smp.c arch/tile: bomb raw_local_irq_ to arch_local_irq_ 2010-11-01 15:30:42 -04:00
smpboot.c BKL: remove extraneous #include <smp_lock.h> 2010-11-17 08:59:32 -08:00
stack.c arch/tile: prevent corrupt top frame from causing backtracer runaway 2010-10-14 15:19:04 -04:00
sys.c BKL: remove extraneous #include <smp_lock.h> 2010-11-17 08:59:32 -08:00
tile-desc_32.c arch/tile: Shrink the tile-opcode files considerably. 2010-07-06 13:40:56 -04:00
time.c arch/tile: bomb raw_local_irq_ to arch_local_irq_ 2010-11-01 15:30:42 -04:00
tlb.c arch/tile: core support for Tilera 32-bit chips. 2010-06-04 17:11:18 -04:00
traps.c arch/tile: enable single-step support for TILE-Gx 2010-10-15 15:38:26 -04:00
vmlinux.lds.S arch/tile: Miscellaneous cleanup changes. 2010-07-06 13:41:51 -04:00