Author: Armin Rigo <[email protected]>
Branch: continulet-jit-2
Changeset: r53126:7c389cf9b418
Date: 2012-03-02 20:44 +0100
http://bitbucket.org/pypy/pypy/changeset/7c389cf9b418/
Log: Found and fix an issue with shadowstack. Hard to test :-(
diff --git a/pypy/jit/backend/x86/assembler.py
b/pypy/jit/backend/x86/assembler.py
--- a/pypy/jit/backend/x86/assembler.py
+++ b/pypy/jit/backend/x86/assembler.py
@@ -758,6 +758,10 @@
#
self.mc.LEA_rm(ebp.value, (eax.value, WORD * (FRAME_FIXED_SIZE-1)))
#
+ gcrootmap = self.cpu.gc_ll_descr.gcrootmap
+ if gcrootmap is not None and gcrootmap.is_shadow_stack:
+ self._fixup_shadowstack_location(gcrootmap)
+ #
if IS_X86_32:
self.mc.ADD_ri(esp.value, 2*WORD)
self.mc.POP_r(save_regs[2].value)
@@ -898,6 +902,15 @@
else:
self.mc.MOV_mr((r13.value, 0), ebx.value) # MOV [r13], ebx
+ def _fixup_shadowstack_location(self, gcrootmap):
+ rst = gcrootmap.get_root_stack_top_addr()
+ if rx86.fits_in_32bits(rst):
+ self.mc.MOV_rj(eax.value, rst) # MOV eax, [rootstacktop]
+ else:
+ self.mc.MOV_ri(eax.value, rst) # MOV eax, rootstacktop
+ self.mc.MOV_rm(eax.value, (eax.value, 0)) # MOV eax, [eax]
+ self.mc.MOV_mr((eax.value, -2*WORD), ebp.value)# MOV [eax-2*WORD], ebp
+
def _call_footer_shadowstack(self, gcrootmap):
rst = gcrootmap.get_root_stack_top_addr()
if rx86.fits_in_32bits(rst):
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