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authorDavid S. Miller <davem@davemloft.net>2010-02-20 02:19:52 +0300
committerDavid S. Miller <davem@davemloft.net>2010-02-20 02:19:52 +0300
commit1f474646fdc36b457606bbcd6a3592e6cbd31ac4 (patch)
tree706149d39c9de0bc0ceacfb2ab44e909caba5b3c
parentd7ecfb3c2aa155c9f6152ebe91de92067d16ba6e (diff)
downloadlinux-1f474646fdc36b457606bbcd6a3592e6cbd31ac4.tar.xz
sparc64: Fix sun4u execute bit check in TSB I-TLB load.
Thanks to testcase and report from Brad Spengler: -------------------- #include <stdio.h> typedef int (* _wee)(void); int main(void) { char buf[8] = { '\x81', '\xc7', '\xe0', '\x08', '\x81', '\xe8', '\x00', '\x00' }; _wee wee; printf("%p\n", &buf); wee = (_wee)&buf; wee(); return 0; } -------------------- TSB I-tlb load code tries to use andcc to check the _PAGE_EXEC_4U bit, but that's bit 12 so it gets sign extended all the way up to bit 63 and the test nearly always passes as a result. Use sethi to fix the bug. Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--arch/sparc/kernel/tsb.S6
1 files changed, 4 insertions, 2 deletions
diff --git a/arch/sparc/kernel/tsb.S b/arch/sparc/kernel/tsb.S
index 8c91d9b29a2f..db15d123f054 100644
--- a/arch/sparc/kernel/tsb.S
+++ b/arch/sparc/kernel/tsb.S
@@ -191,10 +191,12 @@ tsb_dtlb_load:
tsb_itlb_load:
/* Executable bit must be set. */
-661: andcc %g5, _PAGE_EXEC_4U, %g0
- .section .sun4v_1insn_patch, "ax"
+661: sethi %hi(_PAGE_EXEC_4U), %g4
+ andcc %g5, %g4, %g0
+ .section .sun4v_2insn_patch, "ax"
.word 661b
andcc %g5, _PAGE_EXEC_4V, %g0
+ nop
.previous
be,pn %xcc, tsb_do_fault