| Date | Fri, 12 Mar 2010 16:26:11 -0800 | From | Greg KH <> | Subject | [038/145] sparc64: Fix sun4u execute bit check in TSB I-TLB load. |
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2.6.32-stable review patch. If anyone has any objections, please let me know.
---------------- From: David S. Miller <davem@davemloft.net>
[ Upstream commit 1f474646fdc36b457606bbcd6a3592e6cbd31ac4 ]
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> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- arch/sparc/kernel/tsb.S | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
--- 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
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